What's New in 2001

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31 December 2000

    Happy and safe festive season to you all - good health and good coning in 2002 :

29 December 2001

    Ziconotide and cancer pain:
    The Program Abstracts for the 2001 Annual Meeting of the American Society of Clinical Oncology lists two presentations presenting results on the use of Ziconotide (based on omega-conotoxin MVIIA from Conus magus) for the treatment of intractable neuropathic pain.

    Lynn Webster, Raymond R Gaeta, Michael S. Leong and David Ellis (2001) "Ziconotide Efficacy in Patients with Chronic Intractable Pain of Malignant Origin: Efficacy as a Function of Patient Characteristics." ASCO Abstract #1550-2001 ,
    Alpine Medical, Salt Lake City, UT; Stanford University School of Medicine, Stanford, CA; and Elan Pharmaceuticals, Inc., South San Francisco, CA.
    Abstract: Pain is a common and devastating symptom of cancer, occurring in 33% of patients during treatment and in 75-90% of advanced cases. Nearly 75% of cancer patients report moderate/severe pain, yet less than half receive adequate analgesic therapy. Ziconotide, a synthetic peptide derived from the venom of predatory marine snails, is a specific blocker of neuronal N-type calcium channels. Efficacy and safety was evaluated in a double blind, placebo-controlled trial. Eligible patients (n=112) had pain secondary to cancer (88%) or AIDs (12%). Common cancer diagnoses included breast (25%), lung (16%) and colon (12%); 43.5% of cancer patients had metastatic disease while the remainder had pain secondary to localized disease. Baseline pain intensity was moderate to severe (mean VASPI 7.8); VASPI scores improved 53% for ziconotide vs. 18% for placebo, with 73% of ziconotide patients satisfying responder criteria (30% improvement in VASPI) compared to 30% placebo. The degree of improvement with ziconotide was unaffected by age or sex, and was slightly higher for cancer (55% ziconotide, 18% placebo) vs. AIDs (44% ziconotide, 22%placebo). Mean % VASPI improvement was also unaffected by metastatic status; patients with or without metastatic disease had equivalent responses. Patients with or without prior IT morphine (ITM) experience also responded equally well to ziconotide; placebo patients with ITM experience showed slightly better responses. Ziconotide is effective in a large proportion of patients with intractable pain of malignant origin. Efficacy is robust and not affected by patient demographics or disease status; patients with AIDS may respond less than patients with cancer, but patients unresponsive to IT morphine may benefit from ziconotide therapy. These data support ziconotide as a novel, and effective non-opioid alternative to intrathecal or systemic morphine in patients with chronic pain secondary to a wide range of malignancies. This research was sponsored by Elan Pharmaceuticals, Inc.

    Michael S. Leong, Lynn R Webster, David Ellis and Raymond R Gaeta (2001) "Identification of an Effective and Well-Tolerated Dose Range for Ziconotide, a Novel Non-Opioid Anlgesic for Chronic Pain". ASCO Abstract #1550-2001 ,
    Stanford University-School of Medicine, Stanford, CA; Pain and Stress Medicine Institute, Salt Lake City, UT; Elan Pharmaceuticals, Inc., South San Francisco, CA.
    Abstract: Serious pain is a common symptom of cancer, occurring in 20-50% of newly diagnosed and 75-90% of advanced cases. Opioid therapy for pain is often associated with serious side effects. Ziconotide, a synthetic peptide derived from the venom of predatory marine snails, specifically blocks neuronal N-type calcium channels. It represents an alternative to opioids for the treatment of chronic pain. Evaluated in a double-blind, placebo-controlled trial in patients (N=112) with chronic pain secondary to cancer or AIDS, ziconotide was given intrathecally (IT) to patients with moderate-severe pain intensity (measured on the VASPI scale, pain was scored 73.6/100mm for ziconotide vs. 77.9/100mm for placebo, where 100 mm = worst possible pain and 0 mm = least possible pain). Dose-related efficacy observed a pilot trial was used to develop an initial dosing schedule for the controlled trial: initial infusion rate (0.4 mcg/hr) was titrated q12 hrs over 5-6 days to 21.0 mcg/hr. This dosing regimen was subsequently reduced in response to adverse events, to yield an effective and well-tolerated regimen: dose of 0.1 mcg/hr titrated as needed for efficacy q24 hr over 5-6 days, to a maximum of 2.4 mcg/hr. The endpoint %VASPI improvement was slightly higher for the high-rate group (64.1%) than the low-rate group (44.1%). Regardless of initial starting dose, patients tended to show efficacy at doses [greater than or equal to] 0.3 mcg/hr. Common (10%) adverse events were reduced and generally reversible with the low rate regimen, indicating improved tolerability with maintenance of effectiveness. The final regimen was: initiate IT infusion at 0.1 mcg/hr, increasing to 0.2, 0.3, 0.6, 1.2 and 2.4 mcg/hr over 6 days. This dose range and regimen is safe and effective, producing significant analgesia in over 75% of patients treated, confirming ziconotide as an alternative to systemic or IT opioids. This research was sponsored by Elan Pharmaceuticals, Inc

    Confusion observed with Ziconotide:
    Lyn Webster, Robert Henderson, Nat Katz and David Ellis (2001) "Characterization of Confusion, An Adverse Event Associated with Intrathecal Ziconotide Infusion in Chronic Pain Patients" Pain Medicine 2001; 2 (3), 253-254.
    Ziconotide is a novel analgesic currently being developed for intrathecal (IT) infusion to patients with chronic, intractable pain. A long-term safety study has enrolled 586 patients who were titrated to efficacy and treated for up to 180 days. Confusion (COSTART term) is not infrequently observed with ziconotide IT infusion, and is frequently observed with opiates, so it was further characterized. Overall, confusion was observed in 34.3% of patients. Verbatim terms used to describe the observation were fogginess, spaciness, decreased mental alertness, disorientation to time, or mixed up feeling. Confusion occurred with an (mean ± SD) IT infusion rate of 0.30 ± 0.25 (median 0.225) mg/hr (recommended initial IT infusion rate is 0.10 mg/hr). An integrated summary of safety analysis, including trials that forced titration to rates of up to 7.0 mg/hr, revealed that higher IT infusion rates were associated with an increased incidence of all adverse events (AEs), including confusion. In the long-term safety study, the average time to onset of confusion was 49 ± 52 (median 31) days; it was intermittent in 66% and continuous in 31%. Confusion was judged to be severe in 17% of cases; the decision was made to reduce the dose in 49% and discontinue the infusion in 19% of cases. Confusion represented 3.9% of all serious AEs, defined as life-threatening or requiring hospitalization. It occurred with increased frequency when CNS depressants were administered concomitantly. The median confusion duration was 6 days, but resolved within 1 day in 1/3 of patients. It is believed to result from supraspinal distribution of ziconotide, occurs at therapeutic IT doses, is reversible, apparently dose-dependent, mild or moderate in most cases, and does not require cessation of therapy. [This long-term safety study is ongoing and presently enrolling patients; these results will be updated based on a larger dataset at the time of presentation.]

    History of Ziconotide:

  • Prous Science featured Ziconotide as its "Molecule of the Month" for July 2001.
  • The Stanford Magazine, Sept/Oct 2001 gave a brief report on Ziconotide entitled "Now, Snails Aren't Such a Pain"
  • TIME PACIFICJanuary 15, 2001 | NO. 2 feature article on "Potions from Poisons" - Looking for new drugs in unusual places" by ANDREA DORFMAN provided a vignette on cone shell toxins and their pharmaceutical applications.
  • The history of the development of Ziconotide is annotated at the BioSpace web site.
  • The following summary history of Ziconotide appears on the Cognetix Inc. web site : "In December 1999, Elan Corporation plc filed a new drug application (NDA) for ziconotide to receive FDA marketing approval. An approvable letter from the FDA was received by Elan in June 2000. Ziconotide is an w-conopeptide discovered in the University of Utah laboratory of Dr. Olivera. Ziconotide has been developed for the treatment of malignant and neuropathic pain, again employing the Medtronic SynchroMed® infusion system to facilitate intrathecal delivery. In 1998 Elan purchased Neurex Corporation for $740 million in order to acquire the rights to ziconotide".

24 December 2001

19 December 2001

    Cone Shell Images:
    ATLANTIC worldwide specimen shells, P.O.Box 4136, 4461-901 Sª Hora, PORTUGAL, have some nice images of cone shells from Nicobar Is., Taiwain, the Canary Islands and Columbia. Included are:
    Conus betulinus Linné, 1758 +65mm F++/F+++ Very special population, few, very fresh, Nicobar Is. Conus oishii Shikama, 1977, 33.2mm GEM Very rare, few in private collections, this one exceptional, Taiwan Conus siamensis Hwass, 1792, 93mm GEM(-) Beautiful, hard to get this quality, Canary Is. Conus siamensis Hwass, 1792, 120mm F+++ Very fresh and nice, hard to get this size, Canary Is. Conus ( velaensis) complex +31mm F+/F++ Few more just arrived, top color, can't identify precisely, Colombia

17 December 2001

16 December 2001

15 December 2001

14 December 2001

12 December 2001

    Novel recognition site for gamma carboxylation of propeptides:
    Nirmala Pudota, Eric Hommema, Kevin Hallgren, Beth McNally, Susan Lee and Kathleen Berkner from the Department of Molecular Cardiology, Lerner Research Institute and the Jacobs Center for Thrombosis and Vascular Biology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, have identified a second tethering site for carboxylase and vitamin K-dependent proteins (such as the conantokins) that is required for carboxylase activity.
    Pudota,B.N., Hommema,E.L., Hallgren,K.W., McNally,B.A., Lee,S. and Berkner, K.L. (2001) Identification of Sequences within the gama-Carboxylase That Represent a Novel Contact Site with Vitamin K-dependent Proteins and That Are Required for Activity. J. Biol. Chem., 276: 46878-46886
    Abstract: The vitamin K-dependent (VKD) carboxylase converts clusters of Glu residues to gamma-carboxylated Glu residues (Glas) in VKD proteins, which is required for their activity. VKD precursors are targeted to the carboxylase by their carboxylase recognition site, which in most cases is a propeptide. We have identified a second tethering site for carboxylase and VKD proteins that is required for carboxylase activity, called the vitamin K-dependent protein site of interaction (VKS). Several VKD proteins specifically bound an immobilized peptide comprising amino acids 343-355 of the human carboxylase (CVYKRSRGKSGQK) but not a scrambled peptide containing the same residues in a different order. Association with the 343-355 peptide was independent of propeptide binding, because the VKD proteins lacked the propeptide and because the 343-355 peptide did not disrupt association of a propeptide factor IX-carboxylase complex. Analysis with peptides that overlapped amino acids 343-355 indicated that the 343-345 CVY residues were necessary but not sufficient for prothrombin binding. Ionic interactions were also suggested because peptide-VKD protein binding could be disrupted by changes in ionic strength or pH. Mutagenesis of Cys343 to Ser and Tyr345 to Phe resulted in 7-11-fold decreases in vitamin K epoxidation and peptide (EEL) substrate and carboxylase carboxylation, and kinetic analysis showed 5-6-fold increases in Km values for the Glu substrate. These results suggest that Cys343 and Tyr345 are near the catalytic center and affect the active site conformation required for correct positioning of the Glu substrate. The 343-355 VKS peptide had a higher affinity for carboxylated prothrombin (Kd = 5 µM) than uncarboxylated prothrombin (Kd = 60 µM), and the basic VKS region may also facilitate exiting of the Gla product from the catalytic center by ionic attraction. Tethering of VKD proteins to the carboxylase via the propeptide-binding site and the VKS region has important implications for the mechanism of VKD protein carboxylation, and a model is proposed for how the carboxylase VKS region may be required for efficient and processive VKD protein carboxylation.

4 December 2001

    Novel omega-conotoxin from Conus consors:
    Dr. Favreau and colleages from France, report on a novel omega-conotoxin (omega-Ctx CNVIIA) from Conus consors collected in New Caledonia. This conopeptide consists of 27 amino acid residues folded by 3 disulfide bridges and has an unusual sequence (SSSKGR) in loop 4. It exhibits selectivity for N-type voltage sensitive calcium channels (VSCCs) versus P/Q-type VSCCs and provides a new tool for blocking these channels.
    Favreau, P., Gilles, N., Lamthanh, H., Bournaud, R., Shimahara, T., Bouet, F., Laboute, P., Letourneux, Y., Menez, A., Molgo, J. and Le Gall, F. (2001)" A New omega-Conotoxin That Targets N-Type Voltage-Sensitive Calcium Channels with Unusual Specificity".Biochemistry 40: 14567-14575.
    Abstract: A new specific voltage-sensitive calcium channel (VSCC) blocker has been isolated from the venom of the fish-hunting cone snail Conus consors. This peptide, named omega-Ctx CNVIIA, consists of 27 amino acid residues folded by 3 disulfide bridges. Interestingly, loop 4, which is supposed to be crucial for selectivity, shows an unusual sequence (SSSKGR). The synthesis of the linear peptide was performed using the Fmoc strategy, and the correct folding was achieved in the presence of guanidinium chloride, potassium buffer, and reduced/oxidized glutathione at 4 degrees C for 3 days. Both synthetic and native toxin caused an intense shaking activity, characteristic of omega-conotoxins targeting N-type VSCC when injected intracerebroventricularly to mice. Binding studies on rat brain synaptosomes revealed that the radioiodinated omega-Ctx CNVIIA specifically and reversibly binds to high-affinity sites with a K(d) of 36.3 pM. Its binding is competitive with omega-Ctx MVIIA at low concentration (K(i) = 2 pM). Moreover, omega-Ctx CNVIIA exhibits a clear selectivity for N-type VSCCs versus P/Q-type VSCCs targeted respectively by radioiodinated omega-Ctx GVIA and omega-Ctx MVIIC. Although omega-Ctx CNVIIA clearly blocked N-type Ca(2+) current in chromaffin cells, this toxin did not inhibit acetylcholine release evoked by nerve stimuli at the frog neuromuscular junction, in marked contrast to omega-Ctx GVIA. omega-Ctx CNVIIA thus represents a new selective tool for blocking N-type VSCC that displays a unique pharmacological profile and highlights the diversity of voltage-sensitive Ca(2+) channels in the animal kingdom.

3 December 2001

    Chilean Sea Shells:
    Conchas y Carcoles de Chile / Chilean Sea Shells provides help for identification and knowledge of Chilean shells for amateurs of this great hobby. Included is an image of the following cone shell - Conus miliaris, Rehder, 1980 , 2.5 cms, Easter Island.

27 November 2001

26 November 2001

24 November 2001

23 November 2001

    Novel Contryphan-Vn from Conus ventricosus :
    Drs Massilia, Schinina, Ascenzi and Polticelli from the Department of Biology, University "Roma Tre,", Rome, Italy, have extracted a novel contryphan from the venom of the Mediterranean cone shell, Conus ventricosus, (also known as Conus mediterraneus).
    Massilia GR, Schinina ME, Ascenzi P, Polticelli F. (2001) Biochem Biophys Res Commun 288: 908-913
    Abstract: The isolation, purification, and biochemical characterization of the novel peptide Contryphan-Vn, extracted from the venom of the Mediterranean marine snail Conus ventricosus, is reported. Contryphan-Vn is the first Conus peptide described from a vermivorous species and the first purified from the venom of the single Mediterranean Conus species. The amino acid sequence of Contryphan-Vn is As with other contryphans, Contryphan-Vn contains a d-tryptophan residue, is amidated at the C-terminus, and maintains the five-residue intercystine loop size. However, Contryphan-Vn differs from the known contryphans by the insertion of the Asp residue at position 2, by the lack of hydroxylation of Pro(4), and, remarkably, by the presence of the basic residue Lys(6) within the intercystine loop. Although the biological function(s) of contryphans is still unknown, these characteristics suggest distinct molecular target(s) and/or function(s) for Contryphan-Vn.

18 November 2001

15 November 2001

    "Seas of Promise" - Update on COGNETIX Inc.
    Rob Jones, of COGNETIX INC.has brought to my attention an article by Bob Mims in the Salt Lake City Tribune of 11 November, 2001, providing an update on COGNETIX Inc. and describing progress they are making with the development of medicines from cone snail venom components. "One, CGX-1007 (conantokin-G) could reduce or eliminate heretofore untreatable epileptic seizures; another compound, CGX-1160 (contulakin-G), shows promise in relieving post-operative pain...and CGX-1002 (a selective sodium channel blocker) is a long-acting local anesthetic thought especially effective against corneal and burn pain.. (and).. another snail venom product CGX-1204, (in preclinical trials)... has shown promise as a muscle relaxer with potential use in easing emergency room insertion of tracheal airway devices". Click here to see how a conus snail eats its prey.
    [Source: "Seas of Promise" - by Bob Mims published in Salt Lake City Tribune, 11 November, 2001].

14 November 2001

    Conantokins antagonise the NMDA receptor
    Klein, R.C., Warder, S.E., Galdzicki, Z., Castellino, F.J. and Prorok, M. (2001) Kinetic and mechanistic characterization of NMDA receptor antagonism by replacement and truncation variants of the conantokin peptides. Neuropharmacology. 41: 801-810.
    Abstract: The characterization of conantokin-T (con-T), conantokin-R (con-R), and variants thereof, using the whole-cell patch clamp technique, was undertaken to evaluate the contribution of various residues towards the onset and recovery of N-methyl-D-aspartate (NMDA) receptor inhibition in cultured embryonic murine hippocampal neurons. The results obtained indicate that the two most C-terminal gamma-carboxyglutamic acid (Gla) residues of the conantokins, while not essential for activity, provided for more tenacious binding to the receptor. Specifically, con-T[gamma10K/gamma14K] and con-R[gamma11A/gamma15A] displayed 5.6- and 8.4-fold decreases in tau(off), respectively, compared to the parent peptides. For the truncated con-T variants, con-T[1-9/Q6G], and a sarcosine (Src)-containing species, con-T[1-9/G1Src/Q6G], the tau(off) was over 80- and 40-fold faster, respectively, compared to con-T. For the latter peptide, the coapplication of 300&mgr;M spermine enhanced the onset rate constant from 3.1x10(3)M(-1)s(-1) to 12.6x10(3)M(-1)s(-1). From analysis of equilibrium dose-inhibition curves using the Cheng-Prusoff equation, a K(i) value of 1.1&mgr;M for the peptide was obtained. Con-T[1-9/G1Src/Q6G] demonstrated an apparent competitive mode of inhibition relative to NMDA. Schild analysis of the data yielded an equilibrium dissociation constant of 2.4&mgr;M for the interaction of con-T[1-9/G1Src/Q6G] with the receptor.

13 November 2001

    Update on "Conus hayesi"
    Werner Korn announced a name change for Conus hayesi Korn 2000 mentioned below (9 November entry). Writing in La Conchiglia 299: page 18, he commented that there is already a fossil cone named hayesi (C. hayesi Arnold 1909) from California. As the intended new species from South Africa was named after Brian Hayes, it was appropriate to use the replacement name Conus brianhayesi Korn 2001 for this new species. Thanks are due to Arnold Zandbergen, The Netherlands, for bringing this to my notice.

12 November 2001

    Exceptional Shells
    Guido Poppe has announced a web site featuring Exceptional Shells. According to Guido, "They are exceptional for at least one reason, or a combination of these reasons. Criteria can be extreme rarity. More beautiful than usual. Unusual locality. Giant sizes or World Record Sizes. A very particular family. Unusual colors. a/o. Prices have nothing in common with normal shells, and you can inquire for their price by e-mail if interested to acquire one or more of the EXCEPTIONAL SHELLS. All specimens come with a certificate in color, on which you will find a print in color of the image that you view now, the text, particular for each species, and your name." Click here for a fast-link to Exceptional CONIDAE.

    Philippines Shells:
    Emanuel GUILLOT DE SUDUIRAUT has updated his Shells of Philippines site with 12 new Cone Shells.
    Conus consors Sowerby I, in Sowerby II, 1833 color form, Panglao isl.; Conus pergrandis (Iredale, 1937) 161.5 mm. Balut isl. 250 m.; Conus distans Hwass in Bruguière, 1792, 97 mm. Calituban isl. Conus eburneus Hwass, in Bruguière, 1792, 73 mm. Zamboanga Sulu sea ; Conus floridulus Adams & Reeve, 1848, Balicasag isl. 140 m.; Conus glaucus Linnaeus, 1758, Aliguay isl. ; Conus mitratus Hwass, in Bruguière, 1792 34 mm. Laminusa isl. Sulu sea; Conus mustelinus Hwass, in Bruguière, 1792 Mactan isl.; Conus omaria Hwass, in Bruguière, 1792, 91 mm. Palawan isl.; Conus pulicarius Hwass, in Bruguière, 1792 62 mm. Calituban isl. ; Conus stupella (Kuroda, 1956), 64 mm. Balut isl., and Conus thalassiarchus Sowerbi I in Sowerby II, 1834, 90 mm. Zamboanga Sulu sea.

9 November 2001

    Xenome Ltd. to develop chi-conopeptides for treatment of pain
    In a media release, Xenome Limited, a Queensland-based biopharmaceutical R&D company announced (Friday 9 November, 2001) the discovery of a novel family of molecules with significant potential for the treatment of pain conditions. The chi-conopeptides (see entry for 9 September, below to article by Sharpe, I.A. et al in Nature Neuroscience 4: 902-907, 2001) were discovered by the Venom Research Group at the Institute for Molecular Bioscience at The University of Queensland, in a project led by Dr Richard Lewis and Professor Paul Alewood. "The chi molecules, and related derivatives, have shown analgesic properties in animal model trials that measure efficacy against neuropathic and inflammatory pain," said Dr Drinkwater, Head of Research and a co-founder of Xenome Ltd. In a second media release, the company announced that it had successfully raised AUD$4.5m from a new share issue. "This investment will enable the company to forge ahead with its established drug discovery program and further develop its drug candidates." said Dr Tony Evans, CEO of Xenome.

    New species of Conus confirmed
    *[Conus hayesi Korn, 2001]- (La Conchiglia 297: 15) - Shell up to 25 mm in length; protoconch of about 1.75 whorls, maximum diameter 1.5-1.6 mm. Ground color white to cream, base stained with brown or violet brown; basic color pattern of last whorl composed of brown spiral elements: spiral lines and/or spiral rows of dashes extending from base to shoulder. Very similar to C. bairstowi Sowerby III. However, the latter grows to 44 mm. Moreover, subadult shells of C. bairstowi differ from similarly sized C. hayesi in their usually narrower last whorl and in their generally higher spire; the spire outline of C. bairstowi tends to be concave or straight, whereas it is rather straight to convex in C. hayesi; the surface sculpture of last whorl is more pronounced, but finer, in C. bairstowi . Type locality: off Transkei, South Africa, in 80-100 m.. [Source: http://coa.acnatsci.org/conchnet/n-cone.html]
    Click here for Images of Conus hayesi.
    See entry for 14 May 2000.
    *NOTE: see announcement of name change above (entry 13 November, 2001). This species now to be known as Conus brianhayesi Korn 2001 (La Conchiglia 299: 18)

6 November 2001

4 November 2001

    Columbian, Mozambique and Indonesian Cones:
    ATLANTIC worldwide specimen shells, P.O.Box 4136, 4461-901 Sª Hora, PORTUGAL, have some nice images of cone shells from Columbia, Mozambique , Indonesia and the Philippines. Included are:
    Conus rosalindensis, Petuch, 1995 [+15mm F++/GEM Rare, only two, for specialist]; Conus rosalindensis, Petuch, 1995 [20,1mm GEM(-) Another with exceptional size]; Conus sanctaemarthae, Vink, 1977 [70,1mm F+++ Outstanding shell, monster size, high quality]; Conus vikingorum, Petuch, 1992 [+35mm F++/GEM Rare and outstanding, top color, only two]; Conus guajira Petuch, 41,5mm F++ Very rare, another beautiful shell, only one, Colombia 85; Conus julieandreae Cargille, 1995 +19mm F++/F+++ Rare, big size for the species, very seldom seen, E. Honduras 70; Conus sanctaemarthae Vink, 1977 60,5mm Outstanding, giant size, beautiful shell, Colombia 85; Conus sp. +27mm F++/F+++ Can't identify, deep water, for specialist, Colombia 45; Conus sp. 30,5mm GEM Rare, very unusual shell, for specialist, Colombia 60; Conus phlogopus Tomlin, 1937 +65mm F++/GEM, spectacular shells, Colombia; Conus sp. +20mm F++/GEM Rare, probably C. velaensis, for specialist, Colombia; Conus spurius Gmelin, 1791 +48mm F++/GEM Very special "orange" form, natural, live taken, Colombia; Conus baeri Röckel & Korn, 1992 39.8mm GEM Very rare, exceptional shell, deep water, Mozambique; Conus victor Broderip, 1842, 34mm GEM Rare, "golden" form, now very hard to get, beautiful shell, Indonesia; Conus ebraeus Linné, 1758 +41mm F+/F++ Outstanding size and color, only two, Philippines; Conus euetrios Sowerby, 1882 +60mm F++/GEM Outstanding quality and deep blue color, Mozambique; Conus paulae Petuch, 1988 +22mm F++/F+++ Rare, trawled specimen, seldom seen, Colombia; and Conus spirofilis Habe & Kosuge, 1970 +22mm F++/GEM Rare, superb little shells, few only, Philippines.

3 November 2001

    Delta-Conotoxin family :
    Dr. Greg Bulaj and colleagues from the Departments of Biology and Pathology, University of Utah, Salt Lake City, Utah 84112, and Department of Pediatrics, Oregon Health Sciences University, Portland, Oregon 97201, have applied a cladistic analysis to identify amino acids critical for the activity of conotoxins.
    Bulaj, G., De La Cruz, R., Azimi-Zonooz, A., West, P., Watkins, M., Yoshikami, D. and Olivera, B.M.(2001)"delta-Conotoxin Structure/Function through a Cladistic Analysis".Biochemistry 40 :13201-13208.
    Abstract: delta-Conotoxins are Conus peptides that inhibit inactivation of voltage-gated sodium channels. The suggestion that delta-conotoxins might be an essential component of the venoms of fish-hunting cone snails which rapidly immobilize their prey [Terlau, H., Shon, K., Grilley, M., Stocker, M., Stuhmer, W., and Olivera, B. M. (1996) Nature 381, 148-151] has not been tested. On the basis of cDNA cloning, all of the fish-hunting Conus analyzed yielded at least one delta-conotoxin sequence. In addition, one delta-conotoxin isolated from the venom of Conus striatus had an amino acid sequence identical to that predicted from cDNA cloning. This new peptide exhibited properties of delta-conotoxins: it targeted sodium channels and potentiated action potentials by slowing channel inactivation. Homologous sequences of delta-conotoxins from two groups (clades) of related fish-hunting Conus species share consensus features but differ significantly from the two known delta-conotoxins from mollusc-hunting Conus venoms. Three large hydrophobic amino acids were conserved; analogues of the previously described delta-conotoxin PVIA with alanine substituted for the conserved amino acids F9 and I12 lost substantial biological activity. In contrast, both the T8A and K13A delta-conotoxin PVIA analogues, where substitutions were at nonconserved loci, proved to be biologically active. Taken together, our results indicate that a cladistic approach can identify amino acids critical for the activity of conotoxins and provide extensive information as to which amino acid substitutions can be made without significant functional consequences.

2 November 2001

    Searchable Invertebrate Reproduction Database :
    The Kewalo Marine Laboratory at the Pacific Biomedical Research Centre, University of Hawaii, has established a searchable Invertebrate Reproducton Database (supported by the National Science Foundation), containing phylogenetic and reproductive information about the reproduction and development of a number of Hawaiian marine species. The tabular HTML output of the search engine can be saved and imported directly into a spreadsheet or database program(e.g. Microsoft Excel or Access). Included in this searchable database is information on the following 21 species of the genus Conus - (Enter [Searchfield = genus] [Keyword = Conus], then Submit) : C. abbreviatus, C. catus, C. ebraeus, C. flavidus, C. hebraeus, C. imperialis, C. leopardus, C. lividus, C. nanus, C. obscurus, C. obscurus, C. pennaceus, C. perthusus, C. pertusus, C. pulicarius, C. quercinus, C. rattus, C. sponsalis, C. striatus, C. textile, C. vexillum and C. vitulinus. Fields included in the database are Phylum, Class, Order, Family, Genus, Species, Reproduction Method, Egg Diameter, Reproductive Season, Development, Occurrence and References.
    Two key references in this area of research are : Frank E. Perron in "The Reproductive Ecology of Conus in Hawaii, 1981"; and 2) J.B. Taylor in "Planktonic Prosobranch Veligers of Kaneohe Bay"
    - Also see two articles by Frank E. Perron in the Internet Hawaiian Shell News (IHSN), March 1998 "Laboratory Culture of Conus Textile" and "Larval Growth and Metamorphosis of Conus", and two articles by Wes Thorsson about Frank's work, one in IHSN, March 1998 "Veliger and Larval Conus Shells of Hawaii - A summary of a paper by Frank E. Perron, Summarized by Wesley Thorsson with additional observations."; and the other by Wes Thorrson in June 1999 IHSN, "Juvenile Molluscs", from which the following is taken:
    "In prior issues of IHSN (9803 and 9804), we have presented research results of Frank Perron in raising Conus species from eggs and his thorough details about the growth of Conus pennaceus .... This type of research is extremely time consuming, but can produce extremely valuable basic information. Perron kept records on C. pennaceus specimens in one area over a number of years, and produced an amazing amount of data. By plotting the frequency of occurrence of a discrete shell lengths at a number of times, he could display a group of the specimens growing with time, due to the fact that this species tends to lay eggs at one season in that area. All in a range of lengths would be one year group. Perron also raised a batch of eggs from a specimen that had been called C. ellisae Kiener, 1845 due to its very different color pattern.. Since we had seen some specimens that had changed from a typical pattern to the “C. ellisae pattern” in a single whorl, we were sure these were actually C. pennaceus. Perron proved this when both patterns were found on the shells that hatched from a single egg case".

    Another article of interest by Frank Perron is in the April 1998 issue of IHSN and is on the growth of Conus pennaceus. Entitled GROWTH, FECUNDITY, AND MORTALITY OF CONUS PENNACEUS IN HAWAII this article describes the early development of Conus pennaceus.
    Back Issues of IHSN above are not available
    on line, but can be obtained on CD by emailing Wes Thorsson with your mail address. CDs are priced at $12.00 for U.S. addresses or $15.00 for non-U.S. addresses payable to Wesley Thorsson, 122 Waialeale St., Honolulu, Hawaii 95825-2020 No credit cards available. [$8.00 goes to the HMS Scholarship fund, the rest to expenses]. Prices are reduced for multiple CDs on the same order.

30 October 2001

    South African Cone Shells:
    Alwyn Marais, from South Africa, has posted 12 images of cone shells on a new shell site, SA Shells that concentrates on the South African region primarily. Included are Conus mozambicus, Conus natalis gilchristi, Conus orbignyi elokismenos, Conus pictus, Conus simplex, Conus tinianus and Conus zulu. There are also some shell books by Prof. Doug Steyn and other shelling items will come on line in the near future.

    Conantokin interaction with NMDA receptor:
    Drs Wittekindt and colleagues from the Department of Neurochemistry, Max-Planck-Institute for Brain Research, Deutschordenstrasse 46, 60528, Frankfurt/Main, Germany, have used homology-based molecular modeling to suggest how Conantokin-G (from Conus geographus) interacts with the NMDA receptor.
    Wittekindt, B., Malany, S., Schemm, R., Otvos, L., Maccecchini, M.L., Laube, B. and Betz, H. (2001) Point mutations identify the glutamate binding pocket of the N-methyl-D-aspartate receptor as major site of Conantokin-G inhibition. Neuropharmacology 41: 753-761.

    Abstract: Conantokin-G (Con-G), a gamma-carboxylglutamate (Gla) containing peptide derived from the venom of the marine cone snail Conus geographus, acts as a selective and potent inhibitor of N-methyl-D-aspartate (NMDA) receptors. Here, the effect of Con-G on recombinant NMDA receptors carrying point mutations within the glycine and glutamate binding pockets of the NR1 and NR2B subunits was studied using whole-cell voltage-clamp recording from cRNA injected Xenopus oocytes. At wild-type receptors, glutamate-induced currents were inhibited by Con-G in a dose-dependent manner at concentrations of 0.1-100 &mgr;M. Substitution of selected residues within the NR2B subunit reduced the inhibitory potency of Con-G, whereas similar mutations in the NR1 subunit had little effect. These results indicate a selective interaction of Con-G with the glutamate binding pocket of the NMDA receptor. Homology-based molecular modeling of the glutamate binding region based on the known structure of the glutamate binding site of the AMPA receptor protein GluR2 suggests how selected amino acid side chains of NR2B might interact with specific residues of Con-G.

    Conantokin selectivity at NMDA receptor:
    Drs Klein and colleagues from the Department of Chemistry and Biochemistry and the W. M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana 46556, USA. have examined the subunit selective antagonism of conantokins for the NMDA receptor.
    Klein, R.C., Prorok, M., Galdzicki, Z. and Castellino, F.J. (2001) The amino acid residue at sequence position 5 in the conantokin peptides partially governs subunit-selective antagonism of recombinant N-methyl-D-aspartate receptors. J Biol Chem. 276:26860-26867.
    Abstract: Whole cell voltage clamp recordings were performed to assess the ability of conantokin-G (con-G), conantokin-T (con-T), and a 17-residue truncated form of conantokin-R (con-R[1-17]) to inhibit N-methyl-d-aspartate (NMDA)-evoked currents in human embryonic kidney 293 cells transiently expressing various combinations of NR1a, NR1b, NR2A, and NR2B receptor subunits. Con-T and con-R[1-17] attenuated ion currents in cells expressing NR1a/NR2A or NR1a/NR2B. Con-G did not affect NMDA-evoked ionic currents in cells expressing NR1a/NR2A, but it showed inhibitory activity in cells expressing NR1a/NR2B receptors and the triheteromeric combination of NR1a/NR2A/NR2B. An Ala-rich con-G analog, con-G[Q6G/gamma7K/N8A/gamma10A/gamma14A/K15A/S16A/N17A] (Ala/con-G, where gamma is Gla), in which all nonessential amino acids were altered to Ala residues, manifested subunit specificity similar to that of con-G, suggesting that the replaced residues are not responsible for selectivity in the con-G framework. A sarcosine-containing con-T truncation analog, con-T[1-9/G1Src/Q6G], inhibited currents in NR1a/NR2A and NR1a/NR2B receptors, eliminating residues 10-21 as mediators of the broad subunit selectivity of con-T. In contrast to the null effects of con-G and Ala/con-G at a NR1a/NR2A-containing receptor, some inhibition ( approximately 40%) of NMDA-evoked currents was effected by these peptides in cells expressing NR1b/NR2A. This finding suggests that the presence of exon 5 in NR1b plays a role in the activity of the conantokins. Analysis of various conantokin analogs demonstrated that Leu(5) of con-G is an important determinant of conantokin selectivity. Taken as a whole, these results suggest that the important molecular determinants on conantokins responsible for NMDA receptor activity and specificity are discretely housed in specific residues of these peptides, thus allowing molecular manipulation of the NMDA receptor inhibitory properties of the conantokins.

25 October 2001

    Solution conformation of alpha-conotoxin EI:
    Park, K.H., Suk, J.E., Jacobsen, R., Gray, W.W., McIntosh, J.M. and Han, K.H. (2001) "Solution conformation of alpha-conotoxin EI, a neuromuscular toxin specific for the alpha{sub1}/{delta} subunit interface of torpedo nicotinic acetylcholine receptor". J Biol Chem. Oct 18 [epub ahead of print]

    Abstract: A high-resolution structure of alpha-conotoxin EI has been determined by (1)H NMR spectroscopy and molecular modeling. alpha-Conotoxin EI has the same disulfide framework as alpha4/7 conotoxins targeting neuronal nicotinic acetylcholine receptor, but antagonizes neuromuscular receptor as alpha3/5 and alphaA conotoxins. The unique binding preference of alpha-conotoxin EI to the alpha(1)/delta subunit interface of Torpedo neuromuscular receptor makes it a valuable structural template for superposition of various alpha-conotoxins possessing distinct receptor subtype specificities. Structural comparison of alpha-conotoxin EI with the gamma-subunit favoring alpha-conotoxin GI suggests that the Torpedo delta-subunit preference of the former originates from its second loop. Superposition of three-dimensonal structures of seven alpha-conotoxins reveals that the estimated size of the toxin-binding pocket in nicotinic acetylcholine receptor is ~ 20 (height) x 20 (width) x 15 (thickness).

    This study complements another, lower resolution, three-dimensional structure of a-conotoxin EI determined earlier by Aldo Franco and Frank Mari from Florida Atlantic University, Florida.
    See: Franco, A. and Mari, F. (1999) "Three-dimensional structure of a-conotoxin EI determined by 1H NMR spectroscopy". Letters in Peptide Science 6: 199-207.
    Abstract: a-Conotoxin EI is an 18-residue peptide (RDOCCYHPTCNMSNPQIC;4–10, 5–18) isolated from the venom of Conus ermineus, the only fish-hunting cone snail of the Atlantic Ocean. This peptide targets specifically the nicotinic acetylcholine receptor (nAChR) found in mammalian skeletal muscle and the electric organ Torpedo, showing a novel selectivity profile when compared to other a-conotoxins. The 3D structure of EI has been determined by 2D-NMR methods in combination with dynamical simulated annealing protocols. A total of 133 NOE-derived distances were used to produce 13 structures with minimum energy that complied with the NOE restraints. The structure of EI is characterized by a helical loop between Thr^9 and Met^12 that is stabilized by the Cys^4-Cys^10 disulfide bond and turns involving Cys^4-Cys^5 and Asn^14-Pro^15. Other regions of the peptide appear to be flexible. The overall fold of EI is similar to that of other a4/7-conotoxins (PnIA/B, MII, EpI). However, unlike these other a4/7-conotoxins, EI targets the muscular type nAChR. The differences in selectivity can be attributed to differences in the surface charge distribution among these a4/7-conotoxins. The implications for binding of EI to the muscular nAChR are discussed with respect to the current NMR structure of EI.

24 October 2001

    Drugs from the Sea - Book Review:
    David Craik from the Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia. (e-mail: d.craik@imb.uq.edu.au) has provided the following book review for Trends in Pharmacological Sciences, Volume 22, Issue 5, 1 May 2001, Page 261 under the by-line "Fishing for new drug leads". The book contains a chapter by Toto Olivera entitled "w-Conotoxin MVIIA: From MarineSnail Venom to Analgesic Drug".
    Drugs from the Sea
    edited by Nobuhiro Fusetani, Karger, Basel, 2000. US$ 121.00 (hardback) (vi +158 pages), ISBN 3 8055 7098 8
    "The hope that the sea would provide a rich new source of drugs or drug leads has been held for more than 30 years, since various symposia began to address this possibility in the 1960s. However, few such agents have progressed to the clinic. This book presents several chapters on the discovery, development and production of drugs from the sea. In the main, the contributing authors were participants at the Naito Conference on Chemical and Biological Basis for the Diversity of Marine Life, held in October 1997.
    A recurring theme of several chapters, and one that explains the so far relatively low success rate for marine drug candidates, is the ‘supply’ issue. Marine bioactive molecules are often only present in tiny amounts. The difficulty of obtaining sufficient materials for study, combined with their often complex structures, has undoubtedly contributed to marine natural products being under-represented in the world’s pharmacopoeia, relative to molecules from terrestrial sources. However, this book points to some promising signs for the future.
    The opening chapter identifies ten marine-derived molecules in clinical trial, including one, conotoxin MVIIA, that is soon expected to reach the market in the USA as a treatment for pain. Indeed, the chapter by Baldomera Olivera describing the discovery and development of this molecule, to be marketed as Ziconotide, was a pleasure to read. The story of how Michael McIntosh, who started as a research student with Olivera at the University of Utah before he even graduated from high school, became involved in the discovery of conotoxin MVIIA should provide inspiration to many young scientists. This molecule is, in fact, just one of dozens of peptide components typically found in the venoms of cone snails. Multiply this by the hundreds of known snail species and it becomes clear that there are potentially many more therapeutically useful molecules awaiting discovery. Snails use their venoms for the capture of prey but the potent ion-channel blocking ability of the conotoxins can also be harnessed for blocking the neurotransmission of pain responses. The adage that one man’s poison is another’s medicine certainly holds true in this case. Overall, this book provides a timely summary of current progress in the field of drugs from the sea".

23 October 2001

    Conantokins - structure function Review:
    Prorok, M. and Castellino, F.J. (2001) Structure-function relationships of the NMDA receptor antagonist conantokin peptides. Curr Drug Targets. 2: 313-322.
    Abstract: The three members of the conantokin peptide family identified to date are conantokin(con)-G, -T and -R. Their defining attributes include a high relative content of gamma-carboxyglutamic acid (Gla), N-terminal sequence identity, as well as considerable overall sequence homology, and antagonism of the N-methyl-D-aspartate receptor (NMDAR). As promising templates for the design of neuroprotective agents, a thorough evaluation of structure-function relationships in these peptides will be invaluable in aiding rational drug modeling. To this end, a comprehensive assessment of the contributions of individual residues to conantokin structure and function is required. The current review summarizes recent efforts in this area, and also includes the effects of peptide length, as well as structural-stabilization and -destabilization on the structural and inhibitory profiles of an extensive panel of conantokin derivatives.

22 October 2001

    Silver cone shells !!:
    For the cone shell collector who has the lot, here are two cone shells - from the collection of Cambodian Silver Shells available from the Amazing Grace Elephant Company, Limited in Hong Kong.

    Cone shells of Martinique:
    David Touitou has made a short iconography (unfinished yet) of conidiae he has collected at la Martinique island. Some pictures are of dead specimens because of their rarity. Take a look here at the article by Mr. Roger Le Beon. Included are Conus ambiguus, cacao, cloveri, equinophilus, erminius, genuanus, guinaicus, hybridus, mercator, pinaui, pulcher, unifasciatus and tabidus. Also at the seashell-collector site is a collection of images of Cone Shells from Martinique, (including rare and deepwater species) last updated 19 October, 2001. Included are Conus attenuatus, burryae, daucus, erminius, granulatus, mazei, mindanus, mus, punticulatus, pusillus, regius, riosi and spurius. (These are in addition to the finds of C. regius listed below on 20 August and 27 July, 2001).

    Conotoxin MII used to characterize nicotinic acetylcholine receptors in bovine chromaffin cells:
    Dr. Tachikawa and colleagues from the Department of Pharmacology, School of Medicine, Iwate Medical University, Uchimaru 19-1, 020-8505, Morioka, Japan, have used conotoxin MII (from Conus magus) in a pharmacological study to characterize the major nicotinic acetylcholine receptor subtypes responsible for catecholamine release from bovine chromaffin cells as most probably, a3b4 or a3b4a5.
    Tachikawa, E., Mizuma, K., Kudo, K., Kashimoto. T,, Yamato. S. and Ohta, S.(2001) "Characterization of the functional subunit combination of nicotinic acetylcholine receptors in bovine adrenal chromaffin cells." Neurosci Lett 312: 161-164
    Abstract: The combination of nicotinic acetylcholine receptors (nAChRs) subunits connecting with the secretion of catecholamines in bovine adrenal chromaffin cells was pharmacologically investigated using selective agonists and antagonists for their nAChRs. The EC(50) values (uM) for the agonists that stimulate the catecholamine secretion and the rank order were as follows: nicotine (3.3) >= 1,1-dimethyl-4-phenylpiperazinium (3.5) >(E)-N-methyl-4-(3-pyridinyl)-3-butene-1-amine (14) > cytisine (23) >= acetylcholine (25). However, because both the rank order and the EC(50) values differed considerably from those in the various subunits' combinations expressed in Xenopus oocytes or mammalian cells (e.g. alpha2beta2, alpha3beta4, alpha4beta4, etc.), we could not compare them. On the other hand, the IC(50) values (uM) for the antagonists that inhibit the secretion and the rank order were mecamylamine (0.08) > alpha-conotoxin-MII (alpha-CTX-MII) (0.71) > dihydro-beta-erythroidine (DHbetaE) (48) > alpha-bungarotoxin (alpha-BTX) (no effect). Mecamylamine is a highly selective antagonist for alpha3beta4 nAChRs, and alpha-CTX-MII and alpha-BTX are specific antagonists for alpha3beta2 and alpha7 nAChRs, respectively. DHbetaE is a selective antagonist for the alpha4beta2. It has already been shown that the mRNAs for alpha3, alpha5, alpha7 and beta4 subunits are expressed in the chromaffin cells. Therefore, the subunit combination of nAChRs associated with the catecholamine secretion from bovine adrenal chromaffin cells is suggested to be at least alpha3beta4 or alpha3beta4alpha5. Further, the results indicate that the utilization of the nicotinic agonists as selective ligands for the subunit combination of nAChRs may be not suitable for the characterization of nAChRs.

    From the archives: Cone shell envenomation video:
    TREATING PAIN: Synthetic snail venom may lead to new drugs produced by Heather Ross, reported by Lucky Severson, story by Shawn O’Leary, video edited by Katie Elfsten (source INN Health Surfing Report, Tuesday March 14, 2000; INNX / InterNetwork News. Copyright © 1999-2001)
    Cone snail envenomation - video REAL PLAYER Auto; Medium ; Large ; QUICK TIME Small ; Medium ; Large ; WINDOWS MEDIA PLAYER Small ; Medium ; Large .

    From the archives: Bob Endean (1925-1997):
    Dr. Bob Endean was one of the first to study the pharmacological effects of cone shell venom. A tribute to Bob Endean was presented on Radio Australia in February 1998. Bob Endean was a marine biologist and one of the pioneers of coral reef research. This obituary was published in Reef Encounter, the newsletter of International Society for Reef Studies, in Number 23, pp 9 – 11 in July 1998. An edited version, entitled ‘Eco-warrior of the Great Barrier Reef’, appeared in The Australian newspaper on 29 October 1997. A number of his publications on venomous cone shells are listed below:
    Endean R, Gyr P, Surridge J.(1979)The effects of crude venoms of Conus magus and Conus striatus on the contractile response and electrical activity of guinea-pig cardiac musculature. Toxicon. 17(4):381-95.
    Endean R, Gyr P, Surridge J. (1977) The pharmacological actions on guinea-pig ileum of crude venoms from the marine gastropods Conus striatus and Conus magus. Toxicon. 15(4):327-37.
    Endean R, Surridge J, Gyr P. (1977) Some effects of crude venom from the cones Conus striatus and Conus magus on isolated guinea-pig atria. Toxicon. 15(5):369-74.
    Endean R, Williams H, Gyr P, Surridge J. (1976) Some effects on muscle and nerve of crude venom from the gastropod Conus striatus. Toxicon. 14(4):267-74.
    Endean R, Parish G, Gyr P. (1974) Pharmacology of the venom of Conus geographus. Toxicon. 12(2):131-8.
    Endean R, Gyr P, Parish G. (1974) Pharmacology of the venom of the gastropod Conus magus. Toxicon. 12(2):117-29.
    Endean R, Duchemin C. (1967) The venom apparatus of Conus magus. Toxicon. 4(4):275-84.

16 October 2001

    Origins of cone shell toxin diversity:
    More on this intriguing topic in a recent paper by Olivera, Cruz and colleagues from the National Institute of Molecular Biology and Biotechnology, College of Science, University of the Philippines, Diliman, 1101, Quezon City, Philippines

    Espiritu DJ, Watkins M, Dia-Monje V, Cartier GE, Cruz LJ, Olivera BM. (2001) Venomous cone snails: molecular phylogeny and the generation of toxin diversity. Toxicon, 39: 1899-1916.
    Abstract: In order to investigate the generation of conotoxin diversity, delta-conotoxin sequences from nine Conus species were analyzed in the context of their phylogeny. Using a standard molecular marker, mitochondrial 16S RNA, we determined that the delta-conotoxins were derived from three distinct species clades based on the phylogenetic reconstruction of a large set (>80) of Conus species and other toxoglossate molluscs. Four different mechanisms appear to have contributed to the diversity of the delta-conotoxins analyzed: (1) Speciation: delta-Conotoxins in different species diverge from each other (the prepro regions of orthologous genes somewhat more slowly than the reference rRNA rate, the mature toxin regions significantly faster). (2) Duplication: Intraspecific delta-conotoxin divergence is initiated by gene duplication events, some of which may have predated the species itself. (3) Recombination: A novel delta-conotoxin may arise through recombination of two parental delta-contoxin genes. (4) 'Focal hypermutation': This sudden, almost saltatory change in sequence is always restricted to the mature toxin region.The first three have been recognized previously as mechanisms important for the evolution of gene families in other phylogenetic systems; the last is a remarkable, mechanistically unexplained and specialized feature of Conus peptide diversification.

    Interaction of mu-conotoxin GIIIA with Na channels:
    Dr. Nakamura and colleagues from the Graduate School of Bioagricultural Sciences, Nagoya University, Japan, have studied the role of Arg-13 in mu-conotoxin GIIIA in interactions with skeletal muscle sodium channels.
    Nakamura M, Niwa Y, Ishida Y, Kohno T, Sato K, Oba Y, Nakamura H. (2001) Modification of Arg-13 of mu-conotoxin GIIIA with piperidinyl-Arg analogs and their relation to the inhibition of sodium channels. FEBS Lett 10:503:107-110
    Abstract: mu-Conotoxin GIIIA, a peptide toxin isolated from the marine snail Conus geographus, preferentially blocks skeletal muscle sodium channels in vertebrates. In this study, analogs of mu-conotoxin GIIIA in which essential Arg-13 was replaced with arginine analogs consisting of a piperidyl framework to regulate length and direction of the side chain were synthesized. Synthesized analogs exhibited similar CD and NMR spectra to that of GIIIA, suggesting a three-dimensional structure identical to that of the native toxin. The biological activities of piperidyl analogs were decreased or lost despite the small change in the side chain of Arg-13. The investigated structure-activity relationships in inhibiting electrically stimulated muscle contraction suggest that the guanidinium group at amino acid position 13 interacts best when spaced with three to four carbons and placed in a vertical direction from the peptide loop. Thus, the position of the guanidinium group at Arg-13 of GIIIA must be located in a certain range for its strong interaction with the channel protein.

    Crucial role for N-type Calcium channels in pain perception:
    Hatakeyama S, Wakamori M, Ino M, Miyamoto N, Takahashi E, Yoshinaga T, Sawada K, Imoto K, Tanaka I, Yoshizawa T, Nishizawa Y, Mori Y, Niidome T, Shoji S. (2001) Differential nociceptive responses in mice lacking the alpha(1B) subunit of N-type Ca(2+) channels. Neuroreport 12:2423-2427
    Abstract: The role of N-type Ca(2+) channels in nociceptive transmission was examined in genetically engineered mice lacking the alpha(1B) subunit of N-type channels and in their heterozygote and wild-type littermates. In alpha(1B)-deficient mice, N-type channel activities in dorsal root ganglion neurons and spinal synaptoneurosomes were eliminated without compensation by other types of voltage-dependent Ca(2+) channels. The alpha(1B)-deficient mice showed a diminution in the phase 2 nociceptive responses more extensively than in the phase 1 nociceptive responses of the formalin test. The alpha(1B)-deficient mice exhibited significantly increased thermal nociceptive thresholds in the hot plate test, but failed to increase mechanical nociceptive thresholds in the tail pinch test. These results suggest a crucial role of N-type channels in nociceptive transmission, especially for persistent pain like phase 2 of the formalin test and for nociception induced by thermal stimuli.

    Conantokin Review:
    Castellino, F.J. and Prorok, M. (2000) Conantokins: inhibitors of ion flow through the N-methyl-D-aspartate receptor channels. Curr Drug Targets. 1: 219-235. Review.
    Abstract: Calcium flow through the ion channel of the N-methyl-D-aspartate receptor (NMDAR) has been implicated as contributing to a variety of neuropathologies. This receptor is a complex heteromeric oligomer consisting of different types of subunits, the nature of which governs its properties, as well as its response to a variety of agonists, antagonists, and other types of inhibitors. A new natural series of NMDAR inhibitors, the conantokins, have been shown to be present in the venoms of snails within the genus, Conus. These agents appear to function by inhibition of the spermine/spermidine stimulation of ion flow through the NMDAR channel. These small peptides (17-27 amino acid residues) are highly processed post-translationally. One such processing event is the vitamin K-dependent gamma-carboxylation of glutamate, resulting in placement of gamma-carboxyglutamic acid residues in these peptides. As a result, these peptides then possess the ability to interact with divalent metal ions and concomitantly undergo a conformational alteration. Rational drug design based on the characteristics of these promising peptides requires knowledge of their properties and the manner in which they target the NMDAR. This review summarizes current knowledge in this area.

12 October 2001

3 October 2001

29 September 2001

    VENOM: Striking beauties collection

    The Tennessee Aquarium has mounted a display entitled VENOM: Striking beauties collection. A summary of the creatures and the application of their venom components for beneficial uses is available on the web at Medical Marvel : Venom's Human Side. Included are the Bee, Cameroon red tarantula, Cone shell, Eastern and *Western diamondback rattlesnakes, Giant yellow Israelean scorpion, *Gila monster, Malayan pit viper, Russell's pit viper, Taipan, and the Thailand cobra.

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28 September 2001

    FROM THE ARCHIVE : Two articles about Ziconotide that are still of current interest

    Ziconotide Source on DocMD.com:
    Ziconotide Source - now hosted by DocMD.com - "is an interactive Internet site intended for US audiences. This web site is designed to provide information to physicians and healthcare personnel on important and new aspects of ziconotide, a novel therapeutic modality to treat pain, currently under regulatory review at the US Food and Drug Administration (FDA)". Ziconotide is a synthetic version of conotoxin MVIIA from Conus magus. It has received an "approvable letter" from the FDA for treatment of morphine-resistant neuropathic pain but is yet to receive full approval. This site contains Pain Links, Article Summaries and Clinical Reports about Ziconotide.

    Conquering Pain - new discoveries and treatments offer hope:
    BUSINESS WEEK March 1, 1999: Emily Dickinson tells of the experiences of Laura A. McManus, a 27-year-old from Mount Sinai, N.Y. who is one of the 50 million Americans partly or totally disabled by chronic pain. ''I've been on everything: Darvoset, Percocet, Vicodin, morphine in the pump, Dilaudid in the pump,'' she says. All of these narcotics eventually stopped working, and by 24 she had upped the dosage to the point where she was so drugged she could barely function. ''I was borderline suicidal,'' she says. However, ''One month after being on Ziconotide, it was 'Wow, I was happy,''' she says. In the following months, she started physical therapy, began walking, lost the 70 pounds she gained while the pain was at its worst, returned to college, and danced at a wedding. ''Now,'' she says, ''I can think. I can express my feelings. I can have children, finish school. I can have a life.'' Ziconotide (Neurex / Elan Pharmaceuticals) is but one of a number of new treatments being developed for treatment of chronic pain. Others include the drugs ABT-594 (Abbott Laboratories) ; Actic (Anesta), Celebrex, Vioxx (Monsanto,Merck), Morphidex (Algos Pharmaceutical), Neurontin (Warner-Lambert Co), Prosaptide TX14(a) (Myelos Neurosciences Corp), and opioid-delivering transplants of encapsulated bovine adrenal chromaffin cells (CytoTherapeutics). These are nicely reviewed by Emily Dickinson and Catherine Arnst, with input from Ellen Licking, in New York and Amy Barrett in Philadelphia in this special feature on Conquering Pain in BusinessWeek from 1999 that includes two informative pages : Defining Pain, and Pain Snipers and a downloadable poster in Adobe .pdf format at Pain's pathway and the drugs that block it.

27 September 2001

    Pain Relieving Agents from Cone Shell Toxin":
    Medical pain specialist Hans Georg Kress was interviewed by the Vienna newspaper "Der Standard" about the new pain relieving agent he developed from cone shell toxin. Read an English translation of this interview describing the work he presented at the Vienna pain symposium in 2000.
    Source: Der Standard, Vienna, Austria, September, 27th, 2000.

25 September 2001

17 September 2001

    Cone Shell feature:
    Robert Nordsieck from Austria has constructed a most comprehensive and informative site entitled The Living World of Molluscs intended for "interested users, laymen as well as specialists, with information on the world of molluscs. The text is, as far as possible, written in simple language and thus can be used in school as well as in university, using the pages as complete research media or using single pages". Includes site search engine, images, movie clips, and a forum. The site is available in German and English. It includes a section on Cone Shells.

11 September 2001

9 September 2001

    Novel cone shell venom components target adrenoceptors and noradrenaline transporters:
    The venom of cone snails contains peptides that target mammalian receptors, often quite selectively. Now, researchers from the University of Queensland and Xenome Ltd. have discovered two new classes of conopeptides, one that targets alpha-1-adrenoceptors, and another that targets the neuronal noradrenaline transporter. Both types of inhibitor are selective to the receptors, acting as reversible noncompetitive inhibitors. Both could provide alternative avenues for the identification of inhibitor drugs.

    Sharpe, I.A., Gehrmann, J., Loughnan, M.L., Thomas, L., Adams, D.A., Atkins, A., Palant, E., Craik, D.J., Adams, D.J., Alewood, P.F. and Lewis, R.J. (2001) "Two new classes of conopeptides inhibit the alpha-1-adrenoceptor and noradrenaline transporter". Nature Neurosci. 4: 902-907.
    Abstract:Cone snails use venom containing a cocktail of peptides ('conopeptides') to capture their prey. Many of these peptides also target mammalian receptors, often with exquisite selectivity. Here we report the discovery of two new classes of conopeptides. One class targets alpha 1-adrenoceptors (rho-TIA from the fish-hunting Conus tulipa), and the second class targets the neuronal noradrenaline transporter (chi-MrIA and chi-MrIB from the mollusk-hunting C. marmoreus). rho-TIA and chi-MrIA selectively modulate these important membrane-bound proteins. Both peptides act as reversible non-competitive inhibitors and provide alternative avenues for the identification of inhibitor drugs.

8 September 2001

4 September 2001

    Listing in AnimalFocus:
    AnimalFocus is a multilingual extensive free listing of quality links to information about animals. Animals are main grouped by usage as pet, as food (farming), for show (zoo), as professional, and finally, in the wild.
    The present "Cone Shells and Conotoxins" homepage is listed under the Category : In the Wild: Water : Animals : Molluscs. Enter Cone shells in the Search box below.
    Animal Focus, all about animals as pets, in farming, in zoos and aquariums, working, and in the wild AnimalFocus.com

3 September 2001

    More Cone Shells in Art:
    Thanks to Marco Bettocchi and Giancarlo Paginelli who responded on CONCH-L mailing list confirming my identification of the cones in the Balthasar's paintings at the Rijksmuseum web site (see entry below for 29 August), and for pointing out that visible in the larger image of the painting with the Conus striatus there is another cone that appears to be a Conus capitaneus (the orange one). Note also that the logo of Giancarlo Paginelli's "Cone Shells" web site is drawn from the darker Rembrandt's engraving, but reversed. Alfonso Pina also responded informing me that he has a malacological art section right on his own web site, and which includes many Dutch masters. Look at http://www.eumed.net/malakos/arte2 . For example, he has there a painting in private collection in New York by Balthasar van der AST entitled Ramo de Flores (1630) that includes a Conus chaldeus and Conus textile; another Flores en jarrón con conchas e insectos,1628-30, entrusted to the National Gallery, London depicting a Conus striatus and a Conus marmoreus, another Bodegón, (1620) with a Conus pennaceus ? and Bodegón (1628), with Conus striatus and marmoreus and a third unidentified cone.

31 August 2001

    Glory-of-the-Atlantic Cone:
    Karen VanderVen, Contributing Editor of Jacksonville Shell Club, recently accompanied Peggy Williams on a trip to Belize. Not only did Karen get common species, including Conus jaspideus Gmelin, 1791 [Jasper Cone], which might be expected, but came back with a Conus granulatus Linnaeus, 1758 [Glory-of-the-Atlantic Cone] (a generous gift from the Dive Shop). You can read Karen's well written, illustrated account of the trip "From The Lamanai Ruins To The San Pedro Lagoon - Ooh, La, La! Shelling In The Belize Experience (September-October, 2001) "at: www.jaxshells.org/belize.htm & jaxshells.org/belize1.htm. While at the Jacksonville Shell Club site, you may be interested to view a collection of other Selected Western Atlantic Conidae and read Selected Past Newsletter Articles including one by Norma Carlson "Now there are two" (July-August 2001) describing the find of a second sinistral Conus floridanus Gabb, 1868 [Florida Cone] (now known as Conus anabathrum Crosse, 1865).

29 August 2001

    Conus at Rijksmuseum, Amsterdam:
    Rembrant owned an extensive collection of art and curiosities which he employed in his compositions. But only once did he make an etching based on an object in his collection. The two prints of the etching of a cone shell shown here are his only still-life prints. The subject of the picture is a marbled cone shell - 'conus marmoreus', also [darker print]- which is found in the Indian Ocean. Rembrandt selected the most interesting angle for the depiction: showing both the spiral at the top and the opening at the side. But he paid little heed to the laws of nature. Because of the print process, the impression in the picture is back to front: the whorl of the shell is anti-clockwise (sinistral instead of dextral). This rarely occurs in real life and has not been reported for Conus marmoreus. On the other hand, Rembrandt remembered to sign and date the work in mirror-image on the plate. (Click on zoom for a larger image that you can move around with your mouse; or look at the Enlarged Image of Conus marmoreus.

    Exotic shells were a favourite item in still life paintings, often in combination with large bouquets of flowers, as in the two floral still life paintings depicting a Conus striatus and Conus capitaneus and a Conus pennaceus by Balthasar van der Ast. [Look at base of vase for the shells, one of which appears to be a Conus striatus with a Conus capitaneus behind ; and in the other a Conus pennaceus. Zoom and scroll image up or look at the Enlarged image containing Conus striatus & capitaneus and Conus pennaceus]

28 August 2001

    w-Conotoxin MVIIA and neuroprotection after ischemia:
    In this study, 'Toto' Olivera and colleagues (Aryan Azimi-Zonooz, Chad B. Kawa and Cheryl D. Dowell) used radiolabeled omega-conotoxin MVIIA (w-MVIIA)on thin sections of gerbil hippocampus, to provide a more detailed localization of N-type Voltage Gated Calcium Channels (VGCCs) than previously reported. In contrast to findings in the rat, the investigators did not observe any demonstrable neuroprotection by w-MVIIA in the gerbil model of cerebral ischemia. This raises the possibility that efficacy of w-MVIIA in rat may be secondary to a decrease in post-ischemic brain temperature. Of value, [125I]w-GVIA can be used as another synaptic marker to assess post-ischemic synaptic changes and organization.
    Azimi-Zonooz, A., Kawa, C.B., Dowell, C.D. & Olivera, B.M. (2001) "Autoradiographic localization of N-type VGCCs in gerbil hippocampus and failure of w-conotoxin MVIIA to attenuate neuronal injury after transient cerebral ischemia". Brain Research, 907:61-70
    Abstract:In the mammalian central nervous system, transient global ischemia of specific duration causes selective degeneration of CA1 pyramidal neurons in hippocampus. Many of the ischemia-induced pathophysiologic cascades that destroy the neurons are triggered by pre- and postsynaptic calcium entry. Consistent with this, many calcium channel blockers have been shown to be neuroprotective in global models of ischemia. w-Conotoxin MVIIA, a selective N-type VGCC blocker isolated from the venom of Conus magus, protects CA1 neurons in the rat model of global ischemia, albeit transiently. The mechanism by which this peptide renders neuroprotection is unknown. We performed high-resolution receptor autoradiography with the radiolabeled peptide and observed highest binding in stratum lucidum of CA3 subfield, known to contain inhibitory neurons potentially important in the pathogenesis of delayed neuronal death. This finding suggested that the survival of stratum lucidum inhibitory neurons might be the primary event, leading to CA1 neuroprotection after ischemia. Testing of this hypothesis required the reproduction of its neuroprotective effects in the gerbil model of global ischemia. Surprisingly, we found that w-MVIIA did not attenuate CA1 hippocampal injury after 5 min of cerebral ischemia in gerbil. Possible reasons are discussed. Lastly, we show that the peptide can be used as a synaptic marker in assessing short and long-term changes that occur in hippocampus after ischemic injury.

24 August 2001

    Conus magus envenomates a fish:
    Photo of Conus magus snail attacking a small fish. After spearing its victim, the snail releases the venom. Toxic components of the venom inhibit neural transmission. One of the venom components isolated by researchers, the peptide omega-conotoxin MVIIA, was found to be an N-type calcium channel antagonist that plays an important role in inhibition of nociception. It was first called SNX-111 (Neurex Corp) and has been developed into the drug Ziconotide (Elan) for the treatment of morphine-resistant neuropathic pain. Source: Article by Peter S. Staats, MD and Veronica Mitchell, MD on "Future Directions for Intrathecal Therapies". For an associated article regarding the pending advances in intrathecal drug therapy for chronic pain, see "Intrathecal Drug Therapy for Chronic Pain: From Basic Science to Clinical Practice" by Patrick M. Dougherty, Ph.D., and Peter S. Staats, M.D., as it appears in Anesthesiology 1999; 91(6):1891-1918

23 August 2001

    Omega-Conotoxin MVIIA binding to N-type calium channels:
    T. Luchian from the Faculty of Physics, Department of Biophysics and Medical Physics, 'Alexandru I. Cuza' University, Blvd. Carol I No. 11, R-6600, Iasi, Romania. [luchian@uaic.ro ] has examined the effect of the beta3 subunit on omega conotoxin MVIIA (also known as SNX-111, Ziconotide) binding to the neuronal N-type calcium channels expressed in Xenopus laevis oocytes.
    Luchian, T. (2001) The influence exerted by the beta(3) subunit on MVIIA omega-conotoxin binding to neuronal N-type calcium channels.Biochim Biophys Acta. 1512: 329-334.
    Abstract: In the present study, two-electrode voltage-clamp techniques have been used to assess the interaction between the MVIIA omega-conotoxin and an isoform of the N-type Ca(2+) channel alpha subunit (alpha(1B-d)). Cloned alpha(1B-d) Ca(2+) channels were expressed in Xenopus laevis oocytes in the presence and absence of the beta(3) subunit. Coexpression of the beta(3) subunit significantly shifted the IC(50) value for MVIIA inhibition of central N-type Ca(2+) channel current. Analysis of the peak conductance vs. depolarising voltage dependence suggested that the beta(3) subunit has no apparent effect on the gating charge which accompanies the closed-open transition of the channels. Instead, coexpression of the beta(3) subunit led to an approx. 10 mV shift to more hyperpolarised potentials in the voltage-dependent activation of N-type Ca(2+) channels. We conclude that MVIIA alters the surface charge on the N-type Ca(2+) channels and might induce allosteric changes on the structure of the channel, leading to an increase in the dissociation constant of MVIIA binding.

    Interstitial Cystitis and Pain:
    The Interstitial Cystitis Association has an excellent and informative web site that contains information about new medications including Ziconotide (SNX-111) from the cone snail Conus magus for the treatment of pain associated with Interstitial Cystitis (IC). Take a read of IC and Pain, by Lucrecia Perilli, Part 2 of a 4-part series. (see also Part I; Part III; and Part IV.

20 August 2001

17 August 2001

    Conantokin Research:
    The conantokins are naturally occurring, gamma-carboxyglutamate (Gla)-containing peptides from Conus venom with NMDA receptor (NMDAR) antagonist properties. Cognetix Inc. of Salt Lake City has one of the conantokins CGX-1007, in clinical trials for controling seizures in patients with intractable epilepsy.

    Klein, R.C., Prorok, M., Galdzicki, Z. and Castellino, F.J. (2001) The amino acid residue at sequence position 5 in the conantokin peptides partially governs subunit-selective antagonism of recombinant N-methyl-D-aspartate receptors. J. Biol. Chem.276: 26860-26867.
    Warder, S.E., Blandl, T., Klein, R.C., Castellino, F.J. and Prorok, M. (2001) Amino acid determinants for NMDA receptor inhibition by conantokin-T.J. Neurochem. 77: 812-822.
    Walker, C.S., Shetty, R.P., Clark, K., Kazuko, S.G., Letsou, A., Olivera, B.M. and Bandyopadhyay, P.K. (2001) On a potential global role for vitamin K-dependent gamma-carboxylation in animal systems. Evidence for a gamma-glutamyl carboxylase in Drosophila. J. Biol. Chem. 276: 7769-7774.
    Blandl, T., Zajicek, J., Prorok, M. and Castellino,F.J. (2001) Sequence requirements for the N-methyl-D-aspartate receptor antagonist activity of conantokin-R.J. Biol. Chem. 276:7391-7396.
    Adams, A.C., Layer, R.T., McCabe, R.T. and Keefe, K.A.(2000) Effects of conantokins on L-3,4-dihydroxyphenylalanine-induced behavior and immediate early gene expression. Eur J Pharmacol. 404:303-313 .

14 August 2001

    Conotoxin-sensitive ion channels - and wound repair in the aged:
    Dr. Zeinab Khalil and colleagues from the National Ageing Research Institute, and Dept. of Biochemistry and Molecular Biology, University of Melbourne, Australia, have shown that omega-conotoxin-sensitive N-type calcium channels are preserved in the aged and are involved in the vascular response to low-frequency electrical stimulation that improves wound healing. Khalil, Z., Merhi, M. and Livett, B.G. (2001) Differential involvement of conotoxin-sensitive mechanisms in neurogenic vasodilatation responses: effects of age. J. Gerontol. A Biol. Sci. Med. Sci. 56: B356-B363

    Abstract: During aging there is a decline in sensory nerve function that is associated with reduced neurogenic inflammation and poor wound repair. The cellular mechanism(s) responsible for this decline in function with age is not well understood. We previously reported that sensory nerves in aged rats release sensory neuropeptides preferentially in response to low-frequency (5 Hz) as compared with higher-frequency (15 Hz) antidromic electrical stimulation, and that low-frequency transcutaneous electrical nerve stimulation accelerates wound healing. The present study investigates possible mechanisms for this preferential response. Using laser Doppler techniques, we have measured changes in blood flow in the base of vacuum-induced blisters induced in the rat hind footpad of young and old animals in response to low-frequency (5 Hz) or high-frequency (15 Hz) electrical stimulation (20 V, 2 ms for 1 minute) of the sciatic nerve. The relative contributions of the sensory neuropeptides, substance P and calcitonin gene-related peptide (CGRP), and of N-type voltage-gated calcium channels to the vascular responses were assessed by using the specific receptor antagonists RP67580, which is 2-(1-imino-2-(2 methoxy phyenyl) ethyl)-7,7 diphenyl-4 perhydroisoindolone-(3aR, 7aR); CGRP(8-37); and omega-conotoxin GVIA (Conus geographus), respectively. The results showed a greater involvement of substance P at high-frequency electrical stimulation and of CGRP at low-frequency stimulation. Our finding that omega-conotoxin-sensitive N-type calcium channel function was preserved with age and was only involved in the vascular response to low-frequency electrical stimulation could explain our previous report demonstrating beneficial effects of low-frequency transcutaneous electrical nerve stimulation to wound repair in aged animals. The current results have important practical implications for improving tissue repair in the aged.

11 August 2001

3 August 2001

    Cone shell venom MINI-REVIEW:
    McIntosh, J.M. and Jones, R.M. (2001) Cone venom - from accidental stings to deliberate injection. Toxicon 39: 1447 - 1451.
    Abstract: Cone snails have long been of note due to their colorful shells and deadly venom. Over the years, a number of people who have encountered these molluscs have been injured or killed by their sting. Biochemical analysis of the venom components has revealed a plethora of peptides and proteins that target a variety of receptors and ion channels. Pharmaceutical companies are now utilizing the selectivity and potency of Conus-derived peptides to develop novel medications for pain, epilepsy and other disorders.

2 August 2001

    Conus catalogue:
    Filmer R.M., (2001) "A catalogue of nomenclature and taxonomy in the living Conidae 1758-1998", In 8vo, broch., pp. 387. Available from Naturama - LIT. 135000 (about USD 60.00).
    A new resource tool for cone collectors

    Cognetix Press Release:
    SALT LAKE CITY, UT - July 31, 2001 Cognetix, Inc., a biopharmaceutical company developing innovative therapies for central and peripheral nervous system disorders, today announced the completion of a Series B-1 financing of $17 million.
    Extract: "The Company will use the proceeds of the financing to advance its compunds in clinical trials and to accelerate its discovery efforts. Cognetix is developing CGX-1007, an NMDA receptor antagonist, for intractable epilepsy in collaboration with Medtronic, Inc., the Minneapolis-based medical device manufacturer. CGX-1002, is a selective sodium channel blocker in preclinical evaluation as a long acting local anesthetic for treating burn pain, ocular pain, and surgical pain. The Company is collaborating with Elan Corporation plc to develop CGX-1160 as a novel, non-opioid analgesic for management of post-operative pain...."

    See this Press Release and others on the Cognetix web page. Cognetix, founded in 1996, emerged from the cone shell venom research of Baldomero Olivera, PhD., at the University of Utah. Cognetix is a privately held company located in Salt Lake City, Utah.

27 July 2001

    Conus regius citrinus:
    David Touitou found an extraordinary large (60 mm) fully orange specimen of Conus regius citrinus at La Martinique Island (French Caribbean) and has written an article describing the find.

26 July 2001

    Conotoxin MI binding to muscle-type nicotinic receptor:
    Dr. Kasheverov and colleagues from Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia, have been studying the interaction of alpha-conotoxin MI (from Conus magus) and alpha-conotoxin GI (from Conus geographus) with the muscle-type nicotinic acetylcholine receptor from Torpedo californica, using photoactivatable ligands.
    Kasheverov I, Rozhkova A, Zhmak M, Utkin Y, Ivanov V, Tsetlin VI. (2001) "Photoactivatable alpha-conotoxins reveal contacts with all subunits as well as antagonist-induced rearrangements in the Torpedo californica acetylcholine receptor" Eur. J. Biochem. 268: 3664-3673
    Abstract: Azidobenzoyl (AzBz) and benzoylbenzoyl (BzBz) derivatives of alpha-conotoxin MI and L-benzoylphenylalanine (Bpa) analogs of alpha-conotoxin GI were synthesized. All these compounds, similarly to native alpha-conotoxins, completely displaced the radioiodinated MI or GI from the membrane-bound nicotinic acetylcholine receptor (AChR) of Torpedo californica. However, the GI(Bpa11) analog was considerably less potent than GI in competing with radioiodinated alpha-bungarotoxin (alphaBgt). Irradiation of iodinated AzBz derivatives bound to AChR resulted in labeling of all AChR subunits. The BzBz and Bpa derivatives gave lower levels of specific cross-linking but considerable labeling at additional sites that was enhanced, rather than suppressed, by an excess of native alpha-conotoxins or alphaBgt. Both equilibrium binding of benzophenone-derivatized alpha-conotoxins and their cross-linking could be totally abolished by physostigmine. The results obtained demonstrate that (a) specific binding sites for alpha-conotoxins and alphaBgt are overlapping but not identical, (b) each of the AChR subunits can be labeled with photoactivatable alpha-conotoxins and (c) enhancement of benzophenone-derivatized alpha-conotoxins cross-linking at additional (physostigmine-related) sites by alphaBgt or GI indicates that these antagonists induce structural alterations in the AChR outside their binding sites.

    Conotoxin MII binding to neuronal-type nicotinic receptor:
    Dr. Marika Quik and colleagues from The Parkinson's Institute, Sunnyvale, California 94089, and Department of Biology and Psychiatry, University of Utah, Salt Lake City, Utah 84112, have been studying the binding of alpha-conotoxin MII (from Conus magus) to the neuronal-type nicotinic acetylcholine receptor in monkey brain using (125)I-alpha-conotoxin MII, a relatively new ligand that identifies alpha3 and/or alpha6 subunits containing nAChR subtypes. They suggest that "development of ligands directed to nAChR subtypes containing alpha3 and/or alpha6 subunits may yield a novel treatment strategy for parkinsonian patients with nigrostriatal dopaminergic degeneration".
    Quik M, Polonskaya Y, Kulak JM, McIntosh JM. (2001) "Vulnerability of 125I-{alpha}-Conotoxin MII Binding Sites to Nigrostriatal Damage in Monkey" J Neurosci 21: 5494-5500

25 July 2001

    Healing Poisons:
    In this colorful 5-page article, Douglas Steel, Associate Editor of Digital IQ, describes in an interview with Brian Anderson, CEO, Cognetix, how this Salt-Lake City based pharmaceutical company sees opportunity in developing peptide toxins from venomous cone shells for healing some of humankind's diseases.
    Steel, D. (2001) "Healing Poisons: Cognetix uses toxin cocktails to combat diseases and ailments" Digital IQ 1: (2) April 2001, pp. 64-68.

    Conus Web - University of Utah:
    The University of Utah - Conus Web site provides an overview of projects on cone shell toxins being undertaken by Prof. Baldomero Olivera and colleagues at the University of Utah. Included is a list of the investigators, a useful listing of cone shells by genus and species (with prey preference) linked to species number designated in Rockel, D., et al. "Manual of the Living Conidae", and an updated list of scientific publications dating from 1981 to this year.

    Treating pain with snail venom:
    INNX Health Surfing with Lucky Severson presented the following TV broadcast TREATING PAIN: Synthetic snail venom may lead to new drugs" on: Tuesday, March 14, 2000. If you missed it, you can take the video playback by clicking on one of three links at this site (depending on your video browser add-on). The program, reported by Lucky Severson, was produced by Heather Ross, story by Shawn O'Leary, video edited by Katie Elfsten. It shows envenomation of a small fish by a cone shell, a visit to the labs in Utah (Cognetix) and a patient undergoing clinical trials of Ziconotide (w-conotoxin MVIIA).
    Would you like to participate in a clinical trial? Find out if you qualify .

24 July 2001

    Mozambique Cones:
    Carlos Humberto Duraes de Carvalho has been collecting shells in Mozambique and has posted images on his web page at http://www.expage.com/shellscarvalho. Take a look at his 31 cone shell images.

18 July 2001

17 July 2001

    Potions from Poisons:
    Adrea Dorfman authored the following article on 'prospecting for new drugs in nature' for Time Magazine, Inc., January 15, 2001 Issue. Medical applications of extracts from the Thailand (Monocled) Cobra, the Phatasmal Poison-Dart Frog, the Southern Copperhead, the Tercio pelo Snake (Fer-de-Lance), the Giant Israel Scorpion, and Cone Snails are featured.
    Click here for the version without illustrations, or here for Time web site version - complete with illustrations.
    Cone Snail: The tropical oceans harbor more than 500 species of cone snails, predatory creatures that stab their prey with harpoons loaded with a paralytic poison. Long prized by shell collectors, they are being scrutinized by drug hunters for potential treatments for neurological and neuromuscular disorders.
    Each species of cone snail produces a unique venom that contains between 50 and 200 pharmacologically active peptides known as conotoxins. The most advanced conotoxin-derived drug in development is Elan Corp.'s Ziconotide, a nonaddictive treatment for severe chronic pain that is awaiting FDA approval. Cognetix, based in Salt Lake City, Utah, recently started clinical trials on a possible epilepsy treatment. Also in the works: potential therapies for schizophrenia, stroke and Parkinson's and Alzheimer's diseases.

    Cone Shell Images:
    Giancarlo Paganelli has updated his Cone Shells collection (currently currently 518 images), with eight new cone images.
    Conus catus Hwass, in Bruguiere, 1792 Tuamotu - 38.6 mm; Conus imperialis f. fuscatus Born, 1778 Mayotte - 52.2 and 53.2 mm; Conus generalis f. krabiensis La Motta 1982, Thailand - 52.2 mm; Conus monile Reeve, 1848 Sri Lanka - 50.8 mm; Conus namocanus Hwass, in Bruguiere, 1792 Madagascar, Tulear - 67.1 mm; Conus princeps f. lineolatus Valenciennes, 1832 - Panama 47.8 mm; Conus rattus f. semivelatus Sowerby III, 1882, Red Sea, Aqaba bay - 40.6 mm; and Conus vexillum f. sumatrensis Hwass, in Bruguiere, 1792, Indonesia, - 81.7 mm.

16 July 2001

    Index of cones by common name:
    At last ! An index of cones (Conus) by common name of the shell. These are on an excellent (and getting better all the time !) photo site called Eddie Hardy's Internet Site to Marine Gastropods - high quality photos, and lots of them.

    "Seashells_Are_Us" has relocated:
    David Schroeder has relocated his Seashells-Are-Us site (now hosted by Concentric, but previously hosted by CalPoly San Luis Obispo). For an introduction to cone shells you wont find a prettier site than this one. The web address is http://www.concentric.net/~Cschroed/html/cones.html. The site includes images of Conus ammiralis, Conus bengalensis, Conus dominicanus, Conus muriculatus floridulus, Conus marmoreus, Conus tulipa, Conus excelsus, and three photos of a Conus textile attacking a Nassarius.
    According to David Schroeder, "in years past, Cone Shells were commonly known as cigarette shells. They got this name because the person who got accidentally stung by a cone shell would have about enough time to smoke a cigarette, before paralysis and death would set in".
    This page is worth a visit for the beautiful specimens of Conus selected. While you are there, take the mollusc quiz.

    Sinistral cone species: when did they vanish?? :
    Ross Mayhewasked on CONCH-L back in Jan '99 about "one of the mysteries of fossil vs recent cones. ie.many fossil cones are sinistral, while NONE of the modern species are (unless i have missed something?). Can anyone tell me when the left-handed cone species died out, and whether this was a sudden or a gradual process? Any speculations Why???"
    David Campbell of "Old Seashells" replied, "Conus adversarius Conrad, 1840, of which probably all of Petuch's "species" of Contraconus are variants, appears in the lower Pliocene, a little over 3.8 million years ago but less than 5 million, about the same time as sinistral Busycon, in the lower Goose Creek Limestone, Tamiami Limestone, and equivalents. It survived until the end of the Pliocene, about 1.6 million years ago (end of the James City Formation, upper Waccamaw Formation, upper Caloosahatchie Formation, and equivalents), a time of widespread extinction of warmer-water taxa in the northwest Atlantic. The extreme variability shown in the lower Pliocene Pinecrest Formation forms disappears earlier, by about 3.5 million years ago.

    Rare sinistral specimens of Conus ventricosus are known from the Recent, but the usually sinistral adversarius lineage is extinct".

    For more information about sinistral Conus species look at the entry in What's New for 4 July 2000.

15 July 2001

    Conantokin conopeptide for epilepsy:
    Cognetix completes Phase I clinical trial of intractable epilepsy treatment: Cognetix, Inc., SALT LAKE CITY, UT announced May 30, 2001 the completion of a Phase I clinical trial of CGX-1007, a compound derived from a venomous sea snail that shows early promise for the treatment of intractable epilepsy when delivered directly into the central nervous system. CGX-1007, a conantokin conopeptide, is a highly selective antagonist of the excitatory NMDA receptor complex and has demonstrated broad-spectrum efficacy in preclinical studies of seizure disorders.
    In January of 2000, Cognetix and Elan teamed up in a joint venture (JV) to develop and commercialize another Cognetix conopeptide, contulakin-G (CGX-1160), to be administered spinally via a modified Elan Medipad® system. This drug/device system is intended to be developed for the short-term management of post-operative pain.

14 July 2001

    Philippine Cones:
    Alain Prugne and Jean Pierre Barbier have updated their Philippines-Cebu Shell News web site with lots of new shells images, including Conus aulicus Linné, 1758. , 119 mm., orange form Palwan, Conus litteratus Linné, 1758, Sulu archipeligo, freak, 106.5 mm., Conus pseudokimioi, da Motta & Martin, 1982, Aliguay island, 28 mm. exceptional size; and two images of Conus omaria Hwaas, 1792, Palawan island, orange form, 37.5 mm; 37.3 mm. with periostracum. Check out their archive of images for previous postings.

    More cone shell images:
    George Sangiouloglou has updated his Web site with lots of new interesting, exceptional, high quality and beautiful seashells. Among them are following cone shells.

9 July 2001

    Review: alpha-conotoxins as drug leads:
    Drs Dutton and Craik from the Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, Australia, have written a review:
    Dutton, J.L. and Craik, D.J. (2001) "alpha-Conotoxins: nicotinic acetylcholine receptor antagonists as pharmacological tools and potential drug leads", Curr Med Chem 8: 327-344.
    Abstract: Conotoxins are small disulfide rich peptides from the venoms of marine cone snails. They target specific nicotinic acetylcholine receptor (nAChR) subtypes with high affinity and potency and are therefore valuable as neuropharmacological probes and potential drug leads. This article gives a general overview of the chemical and biological features of alpha-conotoxins, including their pharmacology, binding interactions and structure. A detailed analysis of recently reported three-dimensional structures from members of different subfamilies of the alpha-conotoxins, including those with 3/5, 4/3, 4/6 and 4/7 spacings of their two intracysteine loops is given. The structures are generally well defined and represent useful frameworks for the display of amino acid residues to target molecules.

    Conotoxin-like peptides from assassin bugs:
    Corzo, G., Adachi-Akahane, S., Nagao, T., Kusui, Y. and Nakajima, T. (2001) Novel peptides from assassin bugs (Hemiptera: Reduviidae): isolation, chemical and biological characterization. FEBS Lett 499: 256-261.
    Abstract: Three novel peptides were isolated from the venomous saliva of predatory reduviids. They were identified by mass spectrometry and HPLC analysis and consist of 34-36 amino acid residues. They are relatively homologous to the calcium channel blockers omega-conotoxins from marine cone snails and belong to the four-loop Cys scaffold structural class. Ptu1, the shortest peptide, was chemically synthesized (sPtu1) and co-eluted with its native form. Circular dichroism spectra of the sPtu1 showed a high content of beta-turns similar to that of omega-conotoxins GVIA and MVIIA. Electrophysiological experiments demonstrated that sPtu1 reversibly blocks the N-type calcium channels expressed in BHK cells.

7 July 2001

    Characterization of Conus delessertii venom:
    Lutz Meyer and Dr. Edgar Heimer from the Centre for Neurobiology in Querétaro and the group of Dr.Lourival Possani of the Instituto de Biotecnología in Cuernavaca, both from the National University of Mexico (Mexico), have started to characterize the venom of the marine snail Conus delessertii using protein chemical analysis and functional tests. According to their web site, the venom contains conotoxins (small disulfide-rich peptides, generally 7-35 amino acids in length), but also larger protein components that are mostly poorly characterized.

30 June 2001

27 June 2001

24 June 2001

23 June 2001

    Conotoxins help define acetylcholine receptor interaction with voltage-gated calcium channels:
    From the Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah, USA comes this study by Drs. Kulak J.M., McIntosh, J.M., Yoshikami, D. and Olivera, B.M. (2001) "Nicotine-evoked transmitter release from synaptosomes: functional association of specific presynaptic acetylcholine receptors and voltage-gated calcium channels". J Neurochem. 77:1581-1589., indicating that different presynaptic termini can have distinctive functional associations of specific nAChRs and voltage-gated calcium channels.
    Abstract: It has previously been shown that nicotine-evoked dopamine release from rat striatal synaptosomes and nicotine-evoked norepinephrine release from hippocampal synaptosomes are mediated by distinct nicotinic acetylcholine receptor (nAChR) subtypes. In the present study, the functional association of these nicotinic receptors with specific subtypes of voltage-gated calcium channels was examined. Cd(2+) (200 uM), as well as omega-conotoxin MVIIC (5 uM), blocks approximately 85% of nicotine-evoked dopamine release from striatal synaptosomes, indicating a major involvement of calcium channels. Furthermore, the toxin-susceptibility suggests that these calcium channels contain alpha(1A) and/or alpha(1B) subunits. Inhibition of nicotine-evoked dopamine release by conotoxins alpha-MII and omega-GVIA is additive and indicates that presynaptic alpha3beta2 nAChRs are functionally coupled to alpha(1A), but not alpha(1B), calcium channel subtypes. Conversely, insensitivity to alpha-AuIB and sensitivity to omega-MVIIC indicate that non-alpha3beta2/alpha3beta4-containing nAChRs are functionally coupled to alpha(1B)-containing calcium channels. In contrast, Cd(2+) blocks only 65% of nicotine-evoked norepinephrine release from hippocampal synaptosomes, indicating that a substantial fraction of this release occurs through mechanisms not involving calcium channels. This Cd(2+)-insensitive component of release is blocked by alpha-AuIB and therefore appears to be triggered by Ca(2+) flowing directly through the channels of presynaptic alpha3beta4 nAChRs. Thus, these data indicate that different presynaptic termini can have distinctive functional associations of specific nAChRs and voltage-gated calcium channels.

    Conotoxin MI: interactions with nicotinic acetylcholine receptor:
    From the Departments of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and the Department of Anatomy and Cell Biology, Universidad Central del Caribe, Bayamon, Puerto Rico 00960-6032, comes a paper by :
    Rao V. L. Papineni, Jovanny Ulloa Sanchez, Krishna Baksi, Irmgard Ursula Willcockson, and Steen E. Pedersen (2001) Site-specific Charge Interactions of alpha-Conotoxin MI with the Nicotinic Acetylcholine Receptor.
    J. Biol. Chem 276: 23589 -
    Abstract: We have tested the importance of charge interactions for alpha-conotoxin MI binding to the nicotinic acetylcholine receptor (AChR). Ionic residues on alpha-conotoxin MI were altered by site-directed mutagenesis or by chemical modification. In physiological buffer, removal of charges at the N terminus, His-5, and Lys-10 had small (2-4-fold) effects on binding affinity to the mouse muscle AChR and the Torpedo AChR. It was also demonstrated that conotoxin had no effect on the conformational equilibrium of either receptor, as assessed by the effects of the noncompetitive antagonist proadifen on conotoxin binding and, conversely, the effect of conotoxin on the affinity of phencyclidine, proadifen, and ethidium. Conotoxin displayed higher binding affinity in low ionic strength buffer; neutralization of Lys-10 and the N terminus by acetylation blocked this affinity shift at the alpha-delta site but not at the alpha-gamma site. It is concluded that Ctx residues Lys-10 and the N terminal interact with oppositely charged receptor residues only at the alpha-delta site, and the two sites have distinct arrangements of charged residues. Ethidium fluorescence experiments demonstrated that conotoxin is formally competitive with a small cholinergic ligand, tetramethylammonium. Thus, alpha-conotoxin MI appears to interact with the portion of the binding site responsible for stabilizing agonist cations but does not do so with a cationic residue and is, consequently, incapable of inducing a conformational change.

19 June 2001

    Contryphans from Conus textile:
    Jimenez EC, Watkins M, Juszczak LJ, Cruz LJ, Olivera BM (2001) Contryphans from Conus textile venom ducts. Toxicon. 39:803-808.
    Abstract: Contryphans are unusual Conus peptides which contain a distinctive post-translational modification, D-tryptophan or D-leucine. cDNA clones encoding new contryphans from the mollusc-hunting cone snail Conus textile were identified and the inferred mature peptides were synthesized: contryphan-Tx (Gly-Cys-Hyp-D-Trp-Gln-Pro-Tyr-Cys-NH(2)), Leu-contryphan-Tx (Cys-Val-D-Leu-Tyr-Pro-Trp-Cys-NH(2)) and contryphan R/Tx which is identical to contryphan-R [Jimenez et al., 1996. Contryphan is a D-tryptophan containing Conus peptide. J. Biol. Chem. 281, 28002-28005]. Leu-contryphan-Tx exhibits a single peak, but contryphan-Tx shows two peaks under reverse-phase high-performance liquid chromatography conditions. Ultraviolet resonance Raman spectroscopy demonstrates a difference in the D-tryptophan dihedral angle for the two contryphan-Tx equilibrium conformers. Both the sequences and in vivo effects of all contryphans isolated suggest that there are two major branches of the contryphan family.

    gamma-Carboxylation present in vertebrates, molluscan systems (i.e. Conus), and Drosophila. :
    Walker CS, Shetty RP, Clark K, Kazuko SG, Letsou A, Olivera BM, Bandyopadhyay PK. (2001) On a Potential Global Role for Vitamin K-dependent gamma-Carboxylation in Animal Systems. Evidence for a gamma-glutamyl carboxylase in drosophila. J Biol Chem. 276: 7769-7774
    .
    Abstract: The vitamin K-dependent gamma-carboxylation of glutamate to gamma-carboxyglutamate was originally well characterized in the mammalian blood clotting cascade. gamma-Carboxyglutamate has also been found in a number of other mammalian proteins and in neuropeptides from the venoms of marine snails belonging to the genus Conus, suggesting wider prevalence of gamma-carboxylation. We demonstrate that an open reading frame from a Drosophila melanogaster cDNA clone encodes a protein with vitamin K-dependent gamma-carboxylase activity. The open reading frame, 670 amino acids in length, is truncated at the C-terminal end compared with mammalian gamma-carboxylase, which is 758 amino acids. The mammalian gene has 14 introns; in Drosophila there are two much shorter introns but in positions precisely homologous to two of the mammalian introns. In addition, a deletion of 6 nucleotides is observed when cDNA and genomic sequences are compared. In situ hybridization to fixed embryos indicated ubiquitous presence of carboxylase mRNA throughout embryogenesis. Northern blot analysis revealed increased mRNA levels in 12-24-h embryos. The continued presence of carboxylase mRNA suggests that it plays an important role during embryogenesis. Although the model substrate FLEEL is carboxylated by the enzyme, a substrate containing the propeptide of a Conus carboxylase substrate, conantokin G, is poorly carboxylated. Its occurrence in vertebrates, molluscan systems (i.e. Conus), and Drosophila and the apparently strong homology between the three systems suggest that this is a highly conserved and widely distributed post-translational modification in biological systems.

18 June 2001

    Cones of Senegal:
    If you are fond of cone shells have a look at Roger Le Béon's account of Cones of Senegal : This article written in June 2001 is informative and richly illustrated and describes cone shells that Roger Le Béon has found during a two year stay in Senegal (1990-1992).

16 June 2001

12 June 2001

    e-Medicine "Neurotoxin - Cone Shell" :
    This article "Neurotoxin - Cone Shell" by Don R Revis, Jr, MD appeared in eMedicine Journal, Volume 1, Number 12, December 6, 2000 and provides a brief review of cone shell toxins and envenomation, including advice about treatment of cone shell stings and after-treatment care. Included are the following topics: Introduction: Background to Cone Shells and envenomations, Pathophysiology, Frequency, Mortality / Morbidity. Clinical: History, Physical, Causes. Differentials: Workup, Lab Studies and Other Tests. Treatment: Medical Care, Surgical Care. Follow Up: Further Inpatient Care, Further Outpatient Care, Prognosis, Patient education. Miscellaneous: Medical-Legal Pitfalls. Bibliography.

    This article has been added to others detailing medical attention for cone shell envenomation, on our 1st aid page.

    Omega-Conotoxin GVIA modulates purinergic receptors :
    Lalo, U.V., Pankratov, Y.V., Arndts, D. and Krishtal, O.A. (2001) Omega-conotoxin GVIA potently inhibits the currents mediated by P2X receptors in rat DRG neurons. Brain Res Bull. 54: 507-512.
    Abstract: We examined effects of omega-conotoxin previously known as a selective blocker of N-type calcium channels, on the adenosine triphosphate (ATP)-induced currents in the rat dorsal root ganglion neurons. These neurons express at least two types of ionotropic purinoreceptors: P2X3 receptors that have very rapid desensitization kinetics and P2X2/X3 heterooligomeric receptor, which exhibits slow desensitization. We have found that omega-conotoxin GVIA potently inhibits the inward currents mediated by both receptor types. This effect was specific for the receptor subtypes: the IC(50) value for responses evoked by 10 &mgr;M ATP was 21.2 +/- 1.7 nM for the P2X3 receptor-mediated responses and 3.84 +/- 0.43 &mgr;M for slower responses mediated by P2X2/X3 heteropolymers. The efficacy of another type of omega-conotoxin, MVIIC, is much lower: at 10 &mgr;M the latter toxin inhibited the rapidly desensitizing response by 65% and the slowly desensitizing response by 18%. The effects of both toxins were reversible and independent on the membrane potential. Omega-Conotoxin GVIA shifted the dose dependence for the agonistic action of ATP on P2X3 receptors to higher concentrations without producing any effect on the kinetics of the response. It is suggested that omega-conotoxin allosterically modulates the receptor properties, rather than competes for the agonist binding site.
    Efficient synthesis of alpha-contoxins:
    Zhmak, M.N., Kasheverov, I.E., Utkin, I.N., Tsetlin, V.I., Vol'pina, O.M. and Ivanov VT.(2001) [Efficient synthesis of natural alpha-conotoxins and their analogs].Bioorg Khim. 27: 83-88. Russian.
    Abstract: An efficient scheme for the synthesis of alpha-conotoxins, containing 12-18 amino acid residues and two disulfide bridges, was proposed. Its advantages are: (1) the avoidance of orthogonal protections of Cys residues; (2) a lower number of stages in a cycle of the peptide chain elongation by the method of solid phase synthesis; (3) the linear product is sufficiently pure for being used at the next stage of the disulfide bond formation without additional purification; and (4) a substantially reduced time of oxidation to disulfides at pH 10, which led to the target product in a high yield. A number of natural alpha-conotoxins (GI, ImI, EI, MII, and SIA), affecting the muscle and neuronal nicotinic acetylcholine receptors of various types, and several new analogues of these conotoxins (in particular, [Tyr10]ImI, [Gln12]GI, and [Ser1]GI) were synthesized by this scheme. They were used for elucidating the spatial structure of alpha-conotoxins by 1H NMR spectroscopy and for studying the ligand-binding sites of their receptors.
    Omega-conotoxin SVIB is antinociceptive in mice:
    Murakami, M., Suzuki, T., Nakagawasai, O., Murakami, H., Murakami, S., Esashi, A., Taniguchi, R., Yanagisawa, T., Tan-No, K., Miyoshi, I., Sasano, H. and Tadano, T.(2001) Distribution of various calcium channel alpha(1) subunits in murine DRG neurons and antinociceptive effect of omega-conotoxin SVIB in mice.Brain Res. 903:231-236.
    Abstract: Immunohistological study revealed the differential localization of subtypes of voltage-dependent calcium channels in the dorsal root ganglion neurons. Intrathecal injection of omega-conotoxin SVIB, an analogue of omega-conotoxin GVIA, which acts on N-type voltage-dependent calcium channels, significantly shortened the licking time in the late phase of a formalin test.
    alpha6beta4-nicotinic receptors in chick retina have high affinity for alpha-conotoxin MII :
    Barabino, B., Vailati, S., Moretti, M., McIntosh, J.M., Longhi, R., Clementi, F. and Gotti, C.(2001) An alpha4beta4 nicotinic receptor subtype is present in chick retina: identification, characterization and pharmacological comparison with the transfected alpha4beta4 and alpha6beta4 subtypes.Mol Pharmacol. 59: 1410-1417
    Abstract: Retina from 1-day-old chicks is a valuable tissue model for studying neuronal nicotinic receptors because it expresses a large number of the developmentally regulated high affinity [(3)H]epibatidine labeled nicotinic receptors. Most of these receptors contain the beta4 subunit associated with different alpha subunits. Using a sequential immunodepletion procedure with anti-alpha6, anti-beta3, anti-beta2, and anti-beta4 antibodies, we purified an alpha4beta4 nicotinic receptor subtype that accounts for approximately 20 to 25% of the high affinity [(3)H]epibatidine labeled receptors present in retina at that developmental time. Immunoprecipitation and Western blotting experiments confirmed that the purified subtype contains only the alpha4 and beta4 subunits. This receptor binds a number of agonists and the antagonist dihydro-beta-erythroidine with nanomolar affinity, whereas it has micromolar affinity for the alpha-conotoxin MII and methyllycaconitine toxins and other nicotinic antagonists. Comparison of the pharmacological profile of this purified native subtype with that of the same subtype transiently expressed in human BOSC23 cells showed that they have very similar rank orders and absolute Ki values for several nicotinic drugs. Finally, because chick retina expresses an alpha6beta4-containing subtype with a high affinity for the alpha-conotoxin MII, we used native and transfected alpha4beta4 and alpha6beta4 subtypes to investigate the relative contributions of the alpha and beta subunits to this binding, and found that the alpha6 subunit determines the high affinity for this toxin.
    carboxy-terminal Gly favours folding of omega-conotoxin precursor :
    Goldenberg, D.P., Koehn, R.E., Gilbert, D.E. and Wagner, G. (2001) Solution structure and backbone dynamics of an omega-conotoxin precursor Protein Sci. 10: 538-550.
    Abstract: Nuclear magnetic resonance spectroscopy was used to characterize the solution structure and backbone dynamics of a putative precursor form of omega-conotoxin MVIIA, a 25-amino-acid residue peptide antagonist of voltage-gated Ca(2+) channels. The mature peptide is found in the venom of a fish-hunting marine snail Conus magus and contains an amidated carboxyl terminus that is generated by oxidative cleavage of a Gly residue. The form examined in this study is identical to the mature peptide except for the presence of the unmodified carboxy-terminal Gly. This form, referred to as omega-MVIIA-Gly, has previously been shown to refold and form its disulfides more efficiently than the mature form, suggesting that the presence of the terminal Gly may favor folding in vivo. The nuclear magnetic resonance (NMR) structure determination indicated that the fold of omega-MVIIA-Gly is very similar to that previously determined for the mature form, but revealed that the terminal Gly residue participates in a network of hydrogen bonds involving both backbone and side chain atoms, very likely accounting for the enhanced stability and folding efficiency. (15)N relaxation experiments indicated that the backbone is well ordered on the nanosecond time scale but that residues 9-15 undergo a conformational exchange processes with a time constant of approximately 35 microseconds. Other studies have implicated this segment in the binding of the peptide to its physiological target, and the observed motions may play a role in allowing the peptide to enter the binding site.
    Control of reversibility of omega-conotoxin binding:
    Feng, Z.P., Hamid, J., Doering, C., Bosey, G.M., Snutch, T.P. and Zamponi GW.(2001) Residue Gly1326 of the N-type calcium channel alpha 1B subunit controls reversibility of omega-conotoxin GVIA and MVIIA block.J Biol Chem. 276: 15728-15735
    Abstract: We recently reported that amino acid residues contained within a putative EF hand motif in the domain III S5-H5 region of the alpha(1B) subunit affected the relative barium:calcium permeability of N-type calcium channels (Feng, Z. P., Hamid, J., Doering, C., Jarvis, S. E., Bosey, G. M., Bourinet, E., Snutch, T. P., and Zamponi, G. W. (2001) J. Biol. Chem. 276, 5726-5730). Since this region partially overlaps with residues previously implicated in block of the channel by omega-conotoxin GVIA, we assessed the effects of mutations in the putative EF hand domain on channel block by omega-conotoxin GVIA and the structurally related omega-conotoxin MVIIA. Both of the toxins irreversibly block the activity of wild type alpha(1B) N-type channels. We find that in addition to previously identified amino acid residues, residues in positions 1326 and 1332 are important determinants of omega-conotoxin GVIA blockade. Substitution of residue Glu(1332) to arginine slows the time course of development of block. Point mutations in position Gly(1326) to either arginine, glutamic acid, or proline dramatically decrease the time constant for development of the block. Additionally, in the G1326P mutant channel activity was almost completely recovered following washout. A qualitatively similar result was obtained with omega-conotoxin MVIIA, suggesting that common molecular determinants underlie block by these two toxins. Taken together the data suggest that residue Gly(1326) may form a barrier, which controls the access of peptide toxins to their blocking site within the outer vestibule of the channel pore and also stabilizes the toxin-channel interaction.

26 May 2001

22 May 2001

15 May 2001

    ZICONOTIDE FOR POSTOPERATIVE PAIN:
    In UC Davis Pain Medicine Reviews, Gagan Mahajan, M.D. Fellow, UC Davis, reports on a study by Peter G. Atanassoff, Maximillian W.B. Harmannsgruber, James Thrasher, Dan Wermeling William Longton, Raymond Gaeta, Tej Singh, Martha Nayo, Dawn McGuire, and Robert Luther, "Ziconotide, A New N-Type Calcium Channel Blocker, Administered Intrathecally for Postoperative Pain", in Regional Anesthesia and Pain Medicine 25 (3) 274-278, 2000.
    Extract: This study was designed to assess the safety and analgesic efficacy of Ziconotide, a new N-type calcium channel blocker, when administered intrathecally before surgical incision for treatment of acute postoperative pain. The authors enrolled thirty patients (ages 39 years-old to 84 years-old) in a randomized, double-blind, placebo-controlled study.The patients either received a continuous infusion of placebo (n = 12), Ziconotide 0.7 micrograms/hr (n = 12) or Ziconotide 7.0 micrograms/hr (n = 6). Though the high-dose Ziconotide group required significantly less morphine equivalent medication(s) than placebo, it was at the expense of severe dizziness, blurred vision, nystagmus and sedation. The conclusion is that the optimal dose of Ziconotide probably lies somewhere between 0.7 ­ 7.0 micrograms/hr. Additional studies will need to be done to further elucidate this.

    CONIDAE - a summary:
    Check out this Web page at Worldwideconchology for a summary of the molluscan family CONIDAE (or cone shells) including on-line literature and printed literature - books, magazines and journals - telling about these fascinating marine snails.

    NAKED TEXTILE CONES !:
    Read about the Naked Textile Cones - quite amazing. Two pages with images describing observations of a C. textile kept in captivity that somehow squirmed and unwound itself out of its shell. Photos here sent to Allan Kohn who commented "I have never observed the phenomenon of a Conus leaving its shell, nor do I have an explanation. Some adverse conditions must have caused the junctions of columellar muscle and shell to weaken". On page 2 is included a diagram showing the visible organs of the Shell-less Conus textile.

14 May 2001

5 May 2001

    Philippine Cones:
    Alain Prugne and Jean Pierre Barbier have updated their Philippines-Cebu Shell News web site with lots of new shells images, including Conus marmoreus Linné, 1758. , 65.5 mm. Sulu archipelago, and two images of Conus pergrandis Iredale, 1937. 92 mm and 92.5 mm, Bohol island. Check out their archive of images for previous postings.

30th April 2001

    Underwater Drama Enacted: cones in trouble:
    Wes Thorsson, Editor of Internet Hawaiian Shell News, a monthly Internet Publication, has drawn my attention to a feature article on p. 22 of the May, 2001 issue of Hawaiian Shell News. The article, entitled "Underwater Drama Enacted" is reprinted from Hawaiian Shell News, June, 1962, page 1, and relates some observations about an underwater drama in which Cypraea maculifera manipulates a Conus lividus. This drama is illustrated by 4 photos taken by Robert Mizuno. We see first a C. maculifera attempting to dine on Conus lividus and a small shrimp standing by for any left-overs. But serious trouble is developing for C. maculifera in the form of a star fish (view photos 2and 3) which has been taking encircling action.

25 April 2001

    Philippines Cones: live images:
    Emmanuel Guillot de Suduiraut has updated and improved his Eurasia Shells website featuring shells of the Philippines, with addition of 9 new families (more than 400 species are illustrated including several Holotypes and Paratypes). The CONIDAE family page contains thumbnail images of 45 different species of cone shells including images of 3 live species (Conus gloriamaris Chemnitz, 1777 Balicasag isl.; Conus kintoki Coomans & Moolenbeek, 1982 Balicasag isl.; and Conus tessulatus Von Born, 1778, 33,6 mm. Calituban isl.)

24 April 2001

    Contryphans from Conus textile:
    Jimenez, E.C., Watkins, M., Juszczak, L.J., Cruz, L.J. and Olivera, B.M.(2001) Contryphans from Conus textile venom ducts. Toxicon. 39: 803-803.
    Abstract: Contryphans are unusual Conus peptides which contain a distinctive post-translational modification, D-tryptophan or D-leucine. cDNA clones encoding new contryphans from the mollusc-hunting cone snail Conus textile were identified and the inferred mature peptides were synthesized: contryphan-Tx (Gly-Cys-Hyp-D-Trp-Gln-Pro-Tyr-Cys-NH(2)), Leu-contryphan-Tx (Cys-Val-D-Leu-Tyr-Pro-Trp-Cys-NH(2)) and contryphan R/Tx which is identical to contryphan-R [Jimenez et al., 1996. Contryphan is a D-tryptophan containing Conus peptide. J. Biol. Chem. 281, 28002-28005]. Leu-contryphan-Tx exhibits a single peak, but contryphan-Tx shows two peaks under reverse-phase high-performance liquid chromatography conditions. Ultraviolet resonance Raman spectroscopy demonstrates a difference in the D-tryptophan dihedral angle for the two contryphan-Tx equilibrium conformers. Both the sequences and in vivo effects of all contryphans isolated suggest that there are two major branches of the contryphan family.

    Contryphan structures:
    Pallaghy PK, He W, Jimenez EC, Olivera BM, Norton RS. (2000) Structures of the contryphan family of cyclic peptides. Role of electrostatic interactions in cis-trans isomerism. Biochemistry 39:12845-12852
    Abstract: The contryphan family of cyclic peptides, isolated recently from various species of cone shell, has the conserved sequence motif NH(3)(+)-X(1)COD-WX(5)PWC-NH(2), where X(1) is either Gly or absent, O is 4-trans-hydroxyproline, and X(5) is Glu, Asp, or Gln. The solution structures described herein of two new naturally occurring contryphan sequences, contryphan-Sm and des[Gly1]-contryphan-R, are similar to those of contryphan-R, the structure of which has been determined recently [Pallaghy et al. (1999) Biochemistry 38, 11553-11559]. The (1)H NMR chemical shifts of another naturally occurring peptide, contryphan-P, indicate that it also adopts a similar structure. All of these contryphans exist in solution as a mixture of two conformers due to cis-trans isomerization about the Cys2-Hyp3 peptide bond. The lower cis-trans ratio for contryphan-Sm enabled elucidation of the 3D structure of both its major and its minor forms, for which the patterns of (3)J(H)(alpha)(HN) coupling constants are very different. As with contryphan-R, the structure of the major form of contryphan-Sm (cis Cys2-Hyp3 peptide bond) contains an N-terminal chain reversal and a C-terminal type I beta-turn. The minor conformer (trans peptide bond) forms a hairpin structure with sheetlike hydrogen bonds and a type II beta-turn, with the D-Trp4 at the 'Gly position' of the turn. The ratio of conformers arising from cis-trans isomerism around the peptide bond preceding Hyp3 is sensitive to both the amino acid sequence and the solution conditions, varying from 2.7:1 to 17:1 across the five sequences. The sequence and structural determinants of the cis-trans isomerism have been elucidated by comparison of the cis-trans ratios for these peptides with those for contryphan-R and an N-acetylated derivative thereof. The cis-trans ratio is reduced for peptides in which either the charged N-terminal ammonium or the X(5) side-chain carboxylate is neutralized, implying that an electrostatic interaction between these groups stabilizes the cis conformer relative to the trans. These results on the structures and cis-trans equilibrium of different conformers suggest a paradigm of 'locally determined but globally selected' folding for cyclic peptides and constrained protein loops, where the series of stereochemical centers in the loop dictates the favorable conformations and the equilibrium is determined by a small number of side-chain interactions.

    "lambda"-Conotoxins from Conus marmoreus:
    Balaji, R.A., Ohtake, A., Sato, K., Gopalakrishnakone, P., Kini, R.M., Seow, K.T. and Bay, B.H. (2000) lambda-conotoxins, a new family of conotoxins with unique disulfide pattern and protein folding. Isolation and characterization from the venom of Conus marmoreus. J Biol Chem 275: 39516-39522
    Abstract: Conotoxins are multiple disulfide-bonded peptides isolated from marine cone snail venom. These toxins have been classified into several families based on their disulfide pattern and biological properties. Here, we report a new family of Conus peptides, which have a novel cysteine motif. Three peptides of this family (CMrVIA, CMrVIB, and CMrX) have been purified from Conus marmoreus venom, and their structures have been determined. Their amino acid sequences are VCCGYK-LCHOC (CMrVIA), NGVCCGYKLCHOC (CMrVIB), and GICCGVSFCYOC (CMrX), where O represents 4-trans-hydroxyproline. Two of these peptides (CMrVIA and CMrX) have been chemically synthesized. Using a selective protection and deprotection strategy during disulfide bond formation, peptides with both feasible cysteine-pairing combinations were generated. The disulfide pattern (C(1)-C(4), C(2)-C(3)) in native toxins was identified by their co-elution with the synthetic disulfide-isomeric peptides on reverse-phase high pressure liquid chromatography. Although cysteine residues were found in comparable positions with those of alpha-conotoxins, these toxins exhibited a distinctly different disulfide bonding pattern; we have named this new family "lambda -conotoxins." CMrVIA and CMrX induced different biological effects when injected intra-cerebroventricularly in mice; CMrVIA induces seizures, whereas CMrX induces flaccid paralysis. The synthetic peptide with lambda-conotoxin folding is about 1150-fold more potent in inducing seizures than the mispaired isomer with alpha-conotoxin folding. Thus it appears that the unique disulfide pattern, and hence the "ribbon" conformation, in lambda-conotoxins is important for their biological activity.

23 April 2001

    w-Conotoxins: site of interaction with N-type calcium channel:
    Feng, Z.P., Hamid, J., Doering, C.J., Bosey, G.M., Snutch, T.P. and Zamponi, G.W. (2001) Residue G1326 of the N-type calcium channel alpha 1 subunit controls reversibility of w-conotoxin GVIA and MVIIA block. J Biol Chem. 2001 Feb 2 [epub ahead of print]
    Abstract: We recently reported that amino acid residues contained within a putative EF hand motif in the domain III S5-H5 region of the a1B subunit affected for the relative barium:calcium permeability of N-type calcium channels (Feng et al., 2001, J. Biol. Chem. Published online). Since this region partially overlaps with residues previously implicated in block of the channel by w-conotoxin GVIA, we assessed the effects of mutations in the putative EF hand domain on channel block by w-conotoxin GVIA and the structurally related w-conotoxin MVIIA. Both of the toxins irreversibly block the activity of wild type a1B N-type channels. We find that in addition to previously identified amino acid residues, residues in positions 1326 and 1332 are important determinants of w-conotoxin GVIA blockade. Substitution of residue E1332 to arginine slows the time course of development of block. Point mutations in position G1326 to either arginine, glutamic acid or proline dramatically decrease the time constant for development of the block. Additionally, in the G1326P mutant channel activity was almost completely recovered following washout. A qualitatively similar result was obtained with w-conotoxin MVIIA, suggesting that common molecular determinants underlie block by these two toxins. Taken together the data suggest that residue G1326 may form a barrier which controls the access of peptide toxins to their blocking site within the outer vestibule of the channel pore and also stabilizes the toxin-channel interaction.

    Xenome receives additional $0.5 million:
    Medica Holdings (the Australian listed biomedical venture equity pooled development fund) announced on 17 April 2001 that it had invested an additional $0.5 million in Xenome (taking its total investment in the company to $2 million). Xenome focuses on the discovery and development of new pharmaceuticals from the venom of Australian animals (including cone snails). Mention is also made of the appointment of Professor Tony Evans to the position of CEO of Xenome. "I am very impressed with Xenome's intellectual property portfolio and the potential of its venom-based molecules to become novel drugs for a range of neurological disorders", said Professor Evans.

    Cone Shells from The Americas:
    Giancarlo Paganelli has updated his Cone Shells collection (currently currently 487 images), with seven new cone images from The Americas:
    Conus abbotti Clench, 1942, Bahamas - 30.7 mm; Conus baccatus Sowerby III, 1876 Panama - 23.1 mm; Conus gradatus Wood, 1828 Mexico - 49.7 mm; Conus lemniscatus carcellesi Martins, 1945 Uruguay - 47.7 mm; Conus orion Broderip, 1833 Panama - 25.4 mm; Conus regius Gmelin, 1791 Martinique - 62.9 mm, and Conus xantocinctus Petuch, 1986 Brazil - 46.6 mm.

21 April 2001

    Conantokin-G analogues bind NMDA receptors in Alzheimer's:
    Lotten Ragnarsson, Peter R. Dodd and Richard J. Lewis* from the Department of Biochemistry and *Drug Design and Development Centre, University of Queensland, Brisbane 4072 Australia, reported that "CONANTOKINS INHIBIT SPERMINE ENHANCED [3 H ]MK-801 BINDING IN NORMAL AND ALZHEIMER DISEASE HUMAN CORTEX" Proceedings Australian Neuroscience Society Annual Meeting, Brisbane 28th-31st Jan 2001
    Abstract: Localized destruction of neurones in specific cortical regions is one of the hallmarks of Alzheimer disease (AD).Over-excitation mediated by the N -methyl-D-aspartate (NMDA)class of glutamate receptors may contribute to this damage.The activation of the NMDA receptor by glutamate and its co-agonist glycine is enhanced by polyamines such as spermine and spermidine,which reach markedly elevated concentrations in AD brain.Ala(7)-and Lys(7)-conantokin-G (con-G)are two synthetic peptide analogues of con-G,originally isolated from the venom of the cone snail Conus geographus ,which have been shown to be non-competitive antagonists at the NMDA polyamine site in studies in experimental animals.In this study we assessed spermine-enhanced [3 H ]MK-801 binding,and its inhibition by the conantokins,in tissue from six different brain areas taken from 6 AD cases and 12 matched controls.The tissue was obtained at autopsy and included areas which are both pathologically affected and relatively spared in AD.Both peptides showed 100%inhibition of spermine-enhanced [3 H ]MK-801 binding.Ala(7)-con-G was the more potent peptide,and was differentially active between pathologically affected and spared areas.Its potency was greater in the AD cases than in the controls in the four pathologically affected regions,but the reverse was true in the two spared regions.In addition,it showed relatively flat dose-response curves in all areas in controls (Hill slopes ~ ˜0.5),but much sharper dose-responses in AD cases (Hill slopes ~ ˜1.0).Lys(7)-con-G showed no selectivity in potency between areas, but its potency was greater in all brain areas in AD cases.These data show that the two con-G analogues vary in their activity at the range of NMDA receptors present in AD and control brain.Ala(7)-con-G is a potential lead for the development of a selective anti-excitotoxic agent.Supported by the Alzheimer 's Association (USA).

13 April 2001

10 April 2001

    Poisonous Plants and Animals - Educational Site:
    Maria Varbanova, Orlin Zhekov, Iliyan Iliev and Angel Mitev (coach), acting as Team C007974 in the ThinkQuest 2000 educational contest, reached final stages of the competition with this imaginative and informative web page on Poisonous Plants and Animals that includes information on the Cone Shell. As a result of their success they won a scholarship as a prize and were Gold Award winners for 2000. [Some of the text and images on Cone Shells and their toxins were resourced (with permission) from the present Cone Shell and Conotoxins HomePage]. You can view their excellent site at this URL- http://library.thinkquest.org/C007974. A picture of the team with the new president and CEO of ThinkQuest, Dr. Terence Rogers (the man with the glasses) is shown here. The information in this site will appear also in the AccessEd booklet entitled "Health and Physical Education Module 3", (Price AUD$25.00); Publisher: AccessEd, Education Queensland, Queensland, Australia.

4 April 2001

    Database of marine taxa from East-Africa & Indian Ocean:
    Jan Haspeslagh informs us (via CONCH-L mail list) that Dr Ward Vandenberghe has been busy compling a taxonomic database of marine taxa from East-Africa & Indian Ocean (called MASDEA). MASDEA is a biogeographic/taxonomic database of marine species in the Western Indian Ocean/East Africa. The Marine Species Database for Eastern Africa was conceived to fill the need for a comprehensive species register for the Western Indian Ocean. The database was originally developed by Edward Vanden Berghe while working as project manager of the RECOSCIX-WIO project in Mombasa, and now maintained as a collaborative venture between the Kenya Marine and Fisheries Research Institute and VLIZ. Jan Haspeslagh has been involved in delivering the literature references mentioned in MASDEA. If it sounds interesting to you, please visit : http://www.vliz.be/Vmdcdata/masdea/index.htm .

    The database can be consulted in three ways :

  • Browse: Navigate through the taxonomic tree by clicking on one of a list of taxon names. eg. Animalia / Mollusca / Gastropoda prosbranchia / Neogastropoda / Conidae --> lists 136 species of Conus
  • Search: go directly to the taxon of interest by entering the (partial) name of the taxon in a search form eg. enter textile under "Taxon name" and select Species under "Taxon rank" and press 'Search' to see the result = Species Conus textile: Family Conidae).
  • List: create checklist for a geographical area (use 'Browse' to see taxonomic lists). Try entering Genus "Conus", Country "Mozambique". Provides a check-list for Genus Conus in Mozambique, with links to relevant literature and other information sources.
    The way information from the database is presented is described on the 'About' screen, but should in most cases be self-explanatory.

3 April 2001

    Conotoxin Review:
    Robert M. Jones, G. Edward, Cartier, J.Michael McIntosh, Grzegorz Bulaj, Vicki E. Farrar and Baldomero M. Olivera (2001) Composition and Therapeutic Utility of Conotoxins from genus Conus. Patent Status 1996-2000. Expert Opinion in Therapeutic Patents 11(4), 603 - 623.
    Abstract: Forward - With an exponentially increasing body of scientific evidence pointing toward the potential of conotoxins for treatment of a wide variety of nervous system and associated neurological disorders, there has been an explosion of activity in this patent area with more than eighty new PCTpublications in the past five years. With the emergence of ziconotide (SNX-111, w-conotoxin MVIIA) as the first clinically used conotoxin for treatment of a neurological disorder, the first part of the new millenium is likely to see many more new filings in this field. The majority of the PCT publications from this period focus on those classes of conopeptides that interact with nicotinic acetylcholine receptors (nAChRs) together with those that block voltage-gated ion channels. This arena has to date been dominated by three research groups; Neurex (a wholly-owned subsidiary of Elan Corp, South San Francisco, CA, USA); Xenome Limited (Brisbane, Australia), together with the Institute for Molecular Bioscience (IMB) University of Queensland collaborating with Biochemistry and Molecular Biology at the University of Melbourne, (Australia); and Cognetix, Inc. (Salt Lake City, UT, USA) together with the University of Utah Research Foundation and the Salk Institute for Biological Studies (La Jolla, CA, USA).

31 March 2001

28 March 2001

    Dr. Stephen W. Doughty joins the list:
    Added Dr. Stephen W. Doughty from Nottingham, UK to the Contact List of folk interested in conotoxins. Stephen uses molecular modelling and computational techniques to model voltage-gated ion channels and then model the interactions of conotoxins with the channels. This research is carried out primarily for the rational design of novel neuroprotective agents, e.g. for stroke. By modelling how marine snail toxins such as conotoxins bind irreversibly to neuronal calcium channels we can use that information to design reversible inhibitors as drugs. Anyone working in this field is welcome to contact him to discuss collaborations, etc. Stephen can be contacted by E-mail: stephen.doughty@nottingham.ac.uk
    ,
.

22 March 2001

    alpha-Conotoxin MI structure:
    Gouda, H., Yamazaki, K., Hasegawa, J. and Hirono, S.(2001) Refinement of the NMR structures of alpha-conotoxin MI using molecular dynamics simulation with explicit solvent water and a full molecular force field. Chem Pharm Bull (Tokyo). 49: 249-252.
    Abstract: Three NMR structures of alpha-conotoxin MI, a potent antagonist of the nicotinic acetylcholine receptor, have been refined using molecular dynamics (MD) simulation with explicit water. Although the convergence of the NMR structures of alpha-conotoxin MI was not sufficient to provide detailed structural features, the average structures obtained from MD simulations converged to one conformation, providing structural characteristics. The resulting structure was also found to be consistent with the results of amide proton-exchange experiments. These results demonstrate that MD simulation with explicit solvent water is very useful in refining NMR structures

    Presynaptic nAChRs in the striatum:
    Nayak, S.V., Dougherty, J.J., McIntosh, J.M. and Nichols, R.A. (2001) Ca(2+) changes induced by different presynaptic nicotinic receptors in separate populations of individual striatal nerve terminals. J Neurochem.76: 1860-1870.
    Abstract: Presynaptic nicotinic acetylcholine receptors likely play a modulatory role in the nerve terminal. Using laser-scanning confocal microscopy, we have characterized physiological responses obtained on activation of presynaptic nicotinic receptors by measuring calcium changes in individual nerve terminals (synaptosomes) isolated from the rat corpus striatum. Nicotine (500 nM) induced Ca(2+) changes in a subset (10-25%) of synaptosomes. The Ca(2+) responses were dependent on extracellular Ca(2+) and desensitized very slowly (several minutes) on prolonged exposure to agonist. The nicotine-induced Ca(2+) responses were dose-dependent and were completely blocked by dihydro-beta-erythroidine (5 uM), differentially affected by mecamylamine (10 uM) and alpha-conotoxin MII (100 nM), and not affected by alpha-bungarotoxin (500 nM). Immunocytochemical studies using well-characterized monoclonal antibodies revealed the presence of the alpha4 and alpha3/alpha5 nicotinic subunits. The nicotine-induced responses were unaffected by prior depolarization or by a mixture of Ca(2+) channel toxins including omega-conotoxin MVIIC (500 nM), omega-conotoxin GVIA (500 nM) and agatoxin TK (200 nM). Our results indicate that nicotinic receptors present on striatal nerve terminals induce Ca(2+) entry largely without involving voltage-gated Ca(2+) channels, most likely by direct permeation via the receptor channel itself. In addition, at least two subpopulations of presynaptic nicotinic receptors reside on separate terminals in the striatum, suggesting distinct modulatory roles.

    kappa-Conotoxin PVIIA structure:
    Savarin P, Zinn-Justin S, Gilquin B. (2001) Variability in automated assignment of NOESY spectra and three-dimensional structure determination: a test case on three small disulfide-bonded proteins. J Biomol NMR. 19: 49-62.
    Abstract: Three independent runs of automatic assignment and structure calculations were performed on three small proteins, calcicludine from the venom of the green mamba Dendroaspis angusticeps, kappa-conotoxin PVIIA from the purple cone Conus purpurascens and HsTX1, a short scorpion toxin from the venom of Heterometrus spinnifer. At the end of all the runs, the number of cross peaks which remained unassigned (0.6%, 1.4% and 2% for calcicludine, kappa-conotoxin and HsTX1, respectively), as well as the number of constraints which were rejected as producing systematic violations (2.7%, 1.0%, and 1.4% for calcicludine, kappa-conotoxin and HsTX1, respectively) were low. The conformation of the initial model used in the procedure (linear model or constructed by homology) has no influence on the final structures. Mainly two parameters control the procedure: the chemical shift tolerance and the cut-off distance. Independent runs of structure calculations, using the same parameters, yield structures for which the rmsd between averaged structures and the rmsd around each averaged structure were of the same order of magnitude. A different cut-off distance and a different chemical shift tolerance yield rmsd values on final average structures which did not differ more than 0.5 A compared to the rmsd obtained around the averaged structure for each calculation. These results show that the procedure is robust when applied to such a small disulfide-bonded protein.

20 March 2001

    Conotoxin CVID (from Conus catus) in clinical trials:
    Shulkes, A., Baldwin, G. and Giraud, A. (2001) Meeting Report: "Regulatory peptides: what do they regulate?" Trends Endocrinol Metab 12 (2) :46-47.
    The 13th International Symposium on Regulatory Peptides was held on 22-26 October 2000 in Cairns, Australia.
    "Paul Alewood (Institute for Molecular Bioscience, Brisbane, Qld, Australia) described his search for new bioactive peptides from the venoms of Australian cone shells (Conidae). The conopeptide toxins are small peptides (10-30 amino acids) that selectively modulate various types and subtypes of the Ca 2+ , Na + , K + , Cl -, NMDA(N-methyl-D-aspartate), ATP and acetylcholine channels. Their relative ease of synthesis and the rigidity conferred by the arrangement of disulfide bonds makes the conopeptides ideal prototypes for the development of peptidomimetic drugs. Indeed, a highly selective conotoxin, Ctx-CVID, which blocks the N-type voltage gated Ca 2+ channel, is now in clinical trials for the treatment of neuropathic pain."
    Reference: Lewis, R.J., Nielsen, K.J., Craik, D.J., Loughnan, M.L., Adams, D.A., Sharpe, I.A., Luchian, T., Adams, D.J., Bond, T., Thomas, L., Jones, A., Matheson, J.L., Drinkwater, R., Andrews, P.R., and Alewood, P.F. (2000) Novel omega-conotoxins from Conus catus discriminate among neuronal calcium channel subtypes. J. Biol. Chem. 275: 35335-35344.

    Cone shell venoms/toxins - A Review:
    Le Gall, F., Favreau, P., Benoit, E., Richard, G., Molgo, J. (1999) [Conus venoms: a source of toxins which interact with membrane- potential-dependent sodium channels]. [Article in French] J. Soc. Biol. 193: 481-493
    Abstract: Marine snails of the genus Conus, as they are carnivorous predators, have a venom apparatus used to capture their prey. The toxins contained in the venoms of Conidae, called conotoxins, are of a particular high degree of diversity and represent powerful tools in the neuroscience field. Indeed, these toxins specifically bind with a high affinity to receptors and ionic channels. Therefore, they provide original pharmacological tools which receive increasing investigation both to identify and study some functions of the nervous systems and to characterize new types and closely related subtypes of receptors or ionic channels. The voltage-gated sodium channel, because of its fundamental role in cell membrane excitability, is the specific target of a large number of animal and vegetal toxins. Actually, at least seven toxin receptor sites have been identified on this channel-protein. These toxins, and in particular conotoxins, are used to precise the role of different types and/or closely related subtypes of sodium channels in the peripheral and central nervous systems. The focus of the present review is to summarize our current knowledge of the consequences of physiological interactions between different conotoxin families and sodium channels.

18 March 2001

    Reverse Coiled Cones:
    In some 31 years of specializing in "reverse coiled" or "abnormally sinistral or dextral" gastropods, Jacksonville Shell Club member Harry G. Lee has assembled a collection of 108 individual species which had coiled in a direction contrary to the norm. This collection includes 72 Recent marine species, two fossil marine and 34 non-marine species. Among the 72 Recent marine species are 6 species of Conus.
    In the list below, shell measurement is presented in cm. followed by collection location and the year collected. A year listed in parentheses is the year a specimen was acquired when the actual year of collection was not available. A "+" following the listed entry indicates that more than one specimen is present in the collection.
  • Conus anabathrum Crosse, 1865. 3.14cm Marco Is., FL. 1967
  • Conus baccatus G. B. Sowerby II, 1877. 2.01cm Coiba Is., (Pacific) Panama. (1991)
  • Conus furvus Reeve, 1843. 3.11cm Midanao, P.I. (1975)
  • Conus infrenatus Reeve, 1848. 3.26cm Jeffreys Bay, South Africa. 1997
  • Conus tinianus Hwass, 1792. 2.81cm Jeffreys Bay, South Africa. 1994 and
  • Conus ventricosus Gmelin, 1791. 1.33cm La Maddalena Is., Sardinia. 1972. +

    North East Florida Cones:
    Six of the following 12 cone shell species from North East Florida have images posted on the Jacksonville Shell Club site :
  • Conus amphiurgus Dall, 1889a Julia's Cone
  • Conus anabathrum Crosse, 1865 Florida Cone
  • Conus burryae Clench, 1942 Mrs. Burry's Cone
  • Conus daucus Hwass, 1792 Carrot Cone
  • Conus delessertii Récluz, 1843 Sozon's Cone
  • Conus ermineus Born 1778 Agate Cone
  • Conus flavescens G. B. Sowerby II, 1834 Flame Cone
  • Conus stearnsii Conrad, 1869 Dusky Cone
  • Conus mus Hwass, 1792 Mouse Cone
  • Conus largilliertii Kiener, 1845 Philippi's Cone
  • Conus spurius atlanticus Clench, 1942 Alphabet Cone and
  • Conus stimpsoni Dall, 1902 Yellow Cone

16 March 2001

    Australian Seashells:
    Patty Jansen has just updated her Australian Shells Homesite. This is an entirely non-commercial site dedicated to identifying Australian shells, especially the smaller and less glamorous ones. There are now 279 species in the site. Included are the following species of Conus :
    Conus anemone, Lamarck 1810
    Conus aplustre, Reeve 1849
    Conus pappiliferus, Sowerby 1834, and
    Conus rutilus, Menke 1843.

15 March 2001

13 March 2001

    Conus geographus:
    Atlantic have a nice site with information about Conus geographus - and some nice images.
    Also, see the warning about this dangerous species.

11 March 2001

    Cone shells feeding preference:
    At the following link I have organized the different species of Cone Snails according to Feeding Preference, namely, Piscivorous (fish eating), Molluscivorous (mollusc eating) and Vermivorous (preying on marine worms). This page is a re-organization of the data appearing on Olivera's site at http://conus.biology.utah.edu/conuslist.html and is far from complete. Please contribute additional information about Conus eating habits to this resource. Send additions / corrections to me at conus@pacific-ocean.com. Where available please provide a source or published reference for the entry.

8 March 2001

    New date for Venoms to Drugs meeting:
    Dr. Paul Alewood has announced that the Venoms to Drugs conference that was to be held at Heron Island, Queensland, Australia, this year has unfortunately, had to be postponed due to an unanticipated building construction on Heron Island. It will now be held next year from the 14th - 19th of July 2002. Although the organizers are disappointed by this late change, they are also very excited as this has allowed them to follow on from the next International Society of Toxinology conference that will be held in nearby Cairns from July 8-12, 2002. The program of the two meetings will be coordinated and complementary in nature - this will ensure that those who attend both meetings will gain immensely. This is a also wonderful opportunity for overseas visitors and their families to make the most of their trip to Australia. We will keep you informed on both meetings.

5 March 2001

1 March 2001

    Interesting Philippine Cones:
    J.P. Barbier has posted seven new cone images on his Phillipines Shell News site. Take a look at Conus crocatus Lamarck, 1810, 71mm, from North Bohol island; Conus leopardus Linné, 1758, 132 mm, Sulu archipelago, Conus tisii Lan, 1978, 89.5mm, Balut Island, Conus lani Crandall, 1979, 59mm, Balut Island, Conus stercusmuscarum. Linné, 1758, Exceptional size 69mm, Palawan Island, Conus hopwoodiTomlin,1936, 32-35mm, Bohol Island, and Conus lithoglyphus Röding, 1798, 52mm, Samar Island - all in the Philippines. These featured shells may change from month to month so go look now :)

27 February 2001

    Painkillers From the Sea:
    Christine Soares has written a concise account for Popular Science (January 2001) about cone shells and the "race to find the next wonder drug". Relating the story of Elan Pharmaceutical's development of Ziconotide from the venom of Conus magus, she illustrates the article with a photograph (by Kerry S. Matz) of an Indo-Pacific cone snail (Conus purpurascens ?) envenomating a small fish. Take a look at http://www.popsci.com/scitech/news/010215.s.html

21 February 2001

18 February 2001

    EU-funded network on conotoxins:
    Mike Fainzilber is coordinating an EU Cell Factory Grant: "From Conopeptide Scaffolds to Analgesic Leads", and has announced the availability of a number of postdoctoral fellowships or Ph.D. studentships to work on conotoxins. The primary objective of this consortium of nine laboratories is the discovery and validation of novel analgesic conopeptides. Experimental approaches will allow candidates to gain expertise in one or more of the following fields: molecular evolution, protein-protein interaction, selection methodologies, structural analyses, mass spectrometry, molecular pharmacology, in vivo drug delivery, and diverse electrophysiological paradigms. For further information please see the Project Overview and C-E-P Home Page at http://www.weizmann.ac.il/CEP/
    Inquiries may be addressed directly to the group leader of interest (according to the contact information on the home page) or to Dr. Michael Fainzilber, Coordinator. Group leaders and Partners are located in the following countries : Israel (Dr. Mike Fainzilber Weizman Institute; Dr. Ami Aronheim, Technion; and Dr. Dalia Gordon, Sigyn Pharmaceuticals, Jerusalem); France (Prof. Andres Menez, CEA, Saclay, Yif-sur-Yvette), UK (Profs. Alma Burlingame, John Wood and Martin Koltzenburg, UCL, London; and Dr. Peter Laing, SynGenix Ltd., Cambridge); and Sweden (Prof. Johan Stenflo, Lund University, Malmo).

16 February 2001

8 February 2001

    Large release of new conotoxin sequences:
    Mike Fainzilber, Rehovot, Israel has released the full data-set of sequences used for his just published evolutionary paper on conopeptides (see entry below for 31 January 2001). The data-set is now freely accessible in Genbank. Just search Entrez nucleotide or protein databases for "conotoxin AND Conticello" to get the complete list. For ready alignments of the eight conopeptide gene families he studied do the search on the PopSet page of Genbank at http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?CMD=search&DB=PopSet

7 February 2001

6 February 2001

31 January 2001

    Conopeptide Hypervariablity:
    Mike Fainzilber from Rehovot, Israel, has addressed the thorny issue of how hypervariability in conopeptide toxin sequences has evolved AND proposed a new basis for conotoxin nomenclature ("we propose that the nomenclature for conopeptide gene families be based on the first four residues of the signal peptide in combination with the Roman numeral defining their cysteine scaffolds"). Take a look and see what you think.
    Conticello, S.G., Gilad, Y., Avidan, N., Ben-Asher, E., Levy, Z. and Fainzilber, M. (2001) "Mechanisms for Evolving Hypervariability: The Case of Conopeptides" Mol. Biol. Evol. 18 (2) :120-131. 2001.
    Abstract: Hypervariability is a prominent feature of large gene families that mediate interactions between organisms, such as venom-derived toxins or immunoglobulins. In order to study mechanisms for evolution of hypervariability, we examined an EST-generated assemblage of 170 distinct conopeptide sequences from the venoms of five species of marine Conus snails. These sequences were assigned to eight gene families, defined by conserved elements in the signal domain and untranslated regions. Order-of-magnitude differences were observed in the expression levels of individual conopeptides, with five to seven transcripts typically comprising over 50% of the sequenced clones in a given species. The conopeptide precursor alignments revealed four striking features peculiar to the mature peptide domain: (1) an accelerated rate of nucleotide substitution, (2) a bias for transversions over transitions in nucleotide substitutions, (3) a position-specific conservation of cysteine codons within the hypervariable region, and (4) a preponderance of nonsynonymous substitutions over synonymous substitutions. We propose that the first three observations argue for a mutator mechanism targeted to mature domains in conopeptide genes, combining a protective activity specific for cysteine codons and a mutagenic polymerase that exhibits transversion bias, such as DNA polymerase V. The high Dn /Ds ratio is consistent with positive or diversifying selection, and further analyses by intraspecific/interspecific gene tree contingency tests weakly support recent diversifying selection in the evolution of conopeptides. Since only the most highly expressed transcripts segregate in gene trees according to the feeding specificity of the species, diversifying selection might be acting primarily on these sequences. The combination of a targeted mutator mechanism to generate high variability with the subsequent action of diversifying selection on highly expressed variants might explain both the hypervariability of conopeptides and the large number of unique sequences per species.
    [Mike says that the corresponding 170 "unitoxin" collection of conopeptide cDNA sequences should be available soon in Genbank]

29 January 2001

    The French Connection:
    Some nice images of cones together with a description of their structure and functions is given (in French) on this site "Les cones toxiques" - by Mr Michel Ghesquiere -Association Conchyliologique du Nord. Images include Conus geographus, Conus textile, Conus tulipa, Conus marmoreus, Conus aulicus, Conus magus, Conus bulatus and Conus gubernator. While you are at it, check out this site by scientific journalist, Stephane Deligorges.

26 January 2001

    Contryphans in Conus textile:
    Baldomero Olivera and colleagues have listed a paper on "Contryphans from Conus textile venom ducts". Jiminez, E.C. Watkins, M., Juszczac, L.J., Cruz, L.J. and Olivera, B.M. (2001)Toxicon 39: 803-808.
    Abstract: Contryphans are unusual Conus peptides which contain a distinctive post-translational modification, D-tryptophan or D-leucine. cDNA clones encoding new contryphans from the mollusc-hunting cone snail Conus textile were identified and the inferred mature peptides were synthesized: contryphan-Tx (Gly-Cys-Hyp-D-Trp-Gln-Pro-Tyr-Cys-NH(2)), Leu-contryphan-Tx (Cys-Val-D-Leu-Tyr-Pro-Trp-Cys-NH(2)) and contryphan R/Tx which is identical to contryphan-R [Jimenez et al., 1996. Contryphan is a D-tryptophan containing Conus peptide. J. Biol. Chem. 281, 28002-28005]. Leu-contryphan-Tx exhibits a single peak, but contryphan-Tx shows two peaks under reverse-phase high-performance liquid chromatography conditions. Ultraviolet resonance Raman spectroscopy demonstrates a difference in the D-tryptophan dihedral angle for the two contryphan-Tx equilibrium conformers. Both the sequences and in vivo effects of all contryphans isolated suggest that there are two major branches of the contryphan family. (PMID: 11137539)

25 January 2001

    Cone Shell Web Site:
    Marco Bettocchi has set up a web site "Conus marmoreus" featuring cone shells. The site has an extensive Bibliography of Cone Shell articles and books, What is this ? (Images), Collectors ABC, News and Tidings, and Links. The site is available in English and Italian. Pay a visit and contribute an image or two to the collection.
    Why "Conus marmoreus " is issued: "Conus marmoreus" is issued with the aim of putting Cones collectors in touch one with another and giving them the possibility to express their own opinions (through the FORUM). Perhaps this will increase the confusion more than ever, or perhaps not. On the other hand it might help to clear up doubts, to fill gaps, to increase own knowledge, to encourage exchanges. I hope, by this, to have offered to all Cones collectors a chance to start a dialogue. I await your answers and proposals, hoping to have aroused your interest.
    Best wishes to all.
    Marco Bettocchi

22 January 2001

18 January 2001

    What do Cone Snails Eat ?:
    This page groups cone snails according to their eating preferences. Listed here are 15 species of piscivorous cones, 11 of molluscivorous, and 6 species of vermivorous cones. All are linked back to the appropriate page(s) in Rochel, Korn and Kohn (1995) Manual of the Living Conidae. (Information extracted and adapted from "Conus overview", a developing web page from Olivera's Utah group).

14 January 2001

    Cone Shell Poisoning:
    The Emergency Medicine site authored by Suzanne Shepherd, MD, MS, DTMH, FACEP and colleagues from Department of Emergency Medicine, University of Pennsylvania Medical Center has been updated and contains 7 pages with information about cone shell stings and treatment, covering the following topics:
  • Introduction (Background, Pathophysiology, Frequency, Mortality/Morbidity)
  • Clinical (History, Physical, Causes)
  • Differentials (Anaphylaxis, Coelenterate and Jellyfish Envenomations, Echinoderm Envenomations, Lion and Stonefish, Stingray Envenomations
  • Workup (Lab Studies, Imaging Studies)
  • Treatment (Prehospital Care, Emergency Department Care, Consultations)
  • Follow-up (Further Inpatient Care, Patient Education)
  • Bibliography
  • New Species of Cone Shells:

    2000

  • Conus gabrielae; C. micropunctatus; C. franciscoi; C. trovaoi; C. flavusalbus. All: Rolan & Rockel, 2000. All: Angola. - Argonauta 13(2): 5-44.
  • Conus moylani A. Delsaerdt, 2000 in Gloria Maris 39(2), The Conidae of the Solomon Islands, part 7, pp24-54 (sept. 2000).
    Source: ATLANTIC - New Species, CONIDAE

    1999

  • Conus gordyi Röckel & Bondarev, 1999. W. Indian Ocean.
    La Conchiglia 31(293): 41-43.
    Abstract: - Shell up to 19.8 mm; postnuclear whorls, except for last whorl, strongly tuberculate; last whorl with about 25 spiral ribbons from base to shoulder, separated by narrow spiral grooves with close-set axial threads. Ground color white, last whorl with 3-4 bands of orange bars or rectangular dashes, spire variably spotted with the same color. Aperture matching the exterior coloration, at times slightly violet basally. Conus praecellens A. Adams, 1854, Conus acutangulus Lamarck, 1810, C. wakayamaensis (Kuroda, l956), C. eugrammatus Bartsch & Rehder, l943, and Conus helgae Blötcher, 1992 are similar species but, among other differences, they are larger, are differently sculptured, and have different color pattern. There are five specimens known of this species. It was collected at Saya de Malha Bank, Mascarenes, West Indian Ocean, in depths to 130 m.
    Source: COA - News of New Species, CONIDAE

9 January 2001

    Conotoxin Review:

    Baldomero M. Olivera and Lourdes J. Cruz (2001) Conotoxins, in retrospect. Toxicon 39: 7-14
    Abstract: 1. Introduction; 2. A brief history; 2.1. First phase: why picking up a cone snail can be fatal; 2.2. Second phase: giving creative undergraduates free rein; 2.3. Third phase: from learning to milk snails to the nirvana cabal; 2.4. Fourth phase: molecular conotoxinology; 3. Conus venoms 2000: a conceptual framework; Acknowledgements; Appendix A.1. Nomenclature of Conus peptides

    Contulakin-G glycosylation:

    Craig, A.G., Park, M., Fischer, W.H., Kang, J., Compain, P. and Piller, F. (2001) Enzymatic glycosylation of contulakin-G, a glycopeptide isolated from Conus venom, with a mammalian ppGalNAc-transferase Toxicon 39: 809-815.
    Abstract: We have determined that the mammalian uridine diphospho-N-acetyl-d-galactosamine:polypeptide N-acetylgalactosaminyl-transferase T1 (EC 2.4.1.41) has the appropriate acceptor substrate specifcity to recognize the non-glycosylated form of contulakin-G (ZSEEGGSNATKKPYIL-OH where Z=pyroglutamic acid) and to transfer GalNAc to the peptide. Both [Thr10] contulakin-G and a pre-contulakin-G30-66 (RGLVPDDITPQLILGSLISRRQSEEGGSNATKKPYIL-OH) were shown to be acceptors for the mammalian enzyme. The site of attachment of the GalNAc residue was determined using chemical and radioactive sequencing techniques. The mammalian enzyme was highly specifc for the Thr10 residue, in which the native peptide was found to be glycosylated, compared with either Ser2 or Ser 7. In the case of pre-contulakin-G, the enzyme was also highly specific for the equivalent threonine residue. These results suggest that the Cone snail uses an enzyme with similar acceptor specificity to that of the mammalian polypeptide N-acetylgalactosaminyltransferase for glycosylating contulakin-G.

    NMR of Conotoxin AuIB:

    Cho J.-H., Mok, K.H., Olivera, B.M., McIntosh, J.M., Park, K.-H. and Han K.-H. (2000) Nuclear magnetic resonance solution conformation of alpha-conotoxin AuIB, an alpha3 beta4 subtype-selective neuronal nicotinic acetylcholine receptor antagonist. Journal of Biological Chemistry, 275, 8680-8685.
    Abstract: The neuronal nicotinic acetylcholine receptors constitute a highly diverse group, with subtypes consisting of pentameric combinations of alpha and beta subunits, alpha-Conotoxins are a homologous series of small peptides that antagonize these receptors. We present the three-dimensional solution structure of alpha-conotoxin AuIB, the first 15-residue alpha-conotoxin known to selectively block the alpha3 beta4 nicotinic acetylcholine receptor subtype. The pair-wise backbone and heavy-atom root mean square deviation for an ensemble of 20 structures are 0.269 and 0.720 respectively. The overall fold of alpha-conotoxin AuIB closely resembles that of the alpha4/7 subfamily alpha-conotoxins. However, the absence of Tyr15, normally present in other alpha4/7 members, results in tight bending of the backbone at the C terminus and effectively renders Asp14 to assume the spatial location of Tyr15 present in other neuronal alpha4/7 alpha-conotoxins. Structural comparison of alpha-conotoxin AuIB with the 32 subtype-specific alpha-conotoxin MII shows different electrostatic surface charge distributions, which may be important in differential receptor subtype recognition.

    NMR of anti-toxic analogue of alpha-conotoxin GI:

    Mok, K.H. and Han K.-H. (1999) NMR solution conformation of an antitoxic analogue of alpha-conotoxin GI: Identification of a common nicotinic acetylcholine receptor alpha 1-subunit binding surface for small ligands and alpha-conotoxins. Biochemistry 38: 11895-11904
    Abstract: The three-dimensional solution conformation of an 11-residue antitoxic analogue of alpha-conotoxin GI, des-Glu1-Cys3Ala!-des-Cys13-conotoxin GI (CANPACGRHYS-NH(2), designated 'GI-15' henceforth), has been determined using two-dimensional (1)H NMR spectroscopy. The disulfide loop region (1C-6C) and the C-terminal tail (8R-11S) are connected by a flexible hinge formed near 7G, and the pairwise backbone rmsds for the former and the latter are 0.58 and 0.65 Å, respectively. Superpositioning GI-15 with the structure of alpha-conotoxin GI shows that the two share an essentially identical fold in the common first disulfide loop region (1C-6C). However, the absence of the second disulfide loop in GI-15 results in segmental motion of the C-terminal half, causing the key receptor subtype selectivity residue 8R (Arg9 in alpha-conotoxin GI) to lose its native spatial orientation. The combined features of structural equivalence in the disulfide loop and a mobile C-terminal tail appear to be responsible for the activity of GI-15 as a competitive antagonist against native toxin. Electrostatic surface potential comparisons of the first disulfide region of GI-15 with other alpha-conotoxins or receptor- bound states of acetylcholine and d-tubocurarine show a common protruding surface that may serve as the minimal binding determinant for the neuromuscular acetylcholine receptor alpha 1-subunit. On the basis of the original 'Conus toxin macrosite model [Olivera, B. M., Rivier, J., Scott, J. K., Hillyard, D. R., and Cruz, L. J. (1991) J. Biol. Chem. 266, 1923-1936], we propose a revised binding model which incorporates these results.

8 January 2001

1 January 2001

    Cyberconchology Updated:
    Guido T. Poppe & Yoshihiro Goto's Conchology home page lists over 4600 images of shells, about 200 alive, and arranged by family. Go to Cyberconchology, Mollusca, CONIDAE. There is also a direct link to Animals4ever (on which you can find even more shells and input your own information). Here there is a specific SEARCH engine listing 1243 entries for CONIDAE. The entries are now also linked to literature references. The Picture Gallery provides a thumbnail view to facilitate an overview of the species you are interested in. eg. entering 'conus' as genus, into The Picture Gallery Search Screen displays 480 thumbnail images of Conus. As of Jan 2001, the total number of images on Conchology exceeded 4600, and on Animals4ever 6000.

    Conotoxin ImI analogues:
    In this paper, Drs Rogers and colleagues from the Department of Chemistry, University of California, Berkeley, CA, 94720, USA report on structure-function relationships for alpha contoxin ImI.
    Rogers, J.P., Luginbuhl, P., Pemberton, K., Harty, P., Wemmer, D.E. and Stevens, R.C. (2000) Structure-activity relationships in a peptidic alpha7 nicotinic acetylcholine receptor antagonist. J Mol Biol 304 : 911-926
    Abstract: alpha-Conotoxins are small disulfide-constrained peptide toxins which act as antagonists at specific subtypes of nicotinic acetylcholine receptors (nACh receptors). In this study, we analyzed the structures and activities of three mutants of alpha-conotoxin ImI, a 12 amino acid peptide active at alpha7 nACh receptors, in order to gain insight into the primary and tertiary structural requirements of neuronal alpha-conotoxin specificity. NMR solution structures were determined for mutants R11E, R7L, and D5N, resulting in representative ensembles of 20 conformers with average pairwise RMSD values of 0.46, 0.52, and 0.62 A from their mean structures, respectively, for the backbone atoms N, C(alpha), and C' of residues 2-11. The R11E mutant was found to have activity near that of wild-type ImI, while R7L and D5N demonstrated activities reduced by at least two orders of magnitude. Comparison of the structures reveals a common two-loop architecture, with variations observed in backbone and side-chain dihedral angles as well as surface electrostatic potentials upon mutation. Correlation of these structures and activities with those from previously published studies emphasizes that existing hypotheses regarding the molecular determinants of alpha-conotoxin specificity are not adequate for explaining peptide activity, and suggests that more subtle features, visualized here at the atomic level, are important for receptor binding. These data, in conjunction with reported characterizations of the acetylcholine binding site, support a model of toxin activity in which a single solvent-accessible toxin side-chain anchors the complex, with supporting weak interactions determining both the efficacy and the subtype specificity of the inhibitory activity. Copyright 2000 Academic Press. PMID: 11124036, UI: 20574023

    alpha-conotoxin SI analogues:
    A paper on alpha conotoxin SI by Dr. Hargittai et al from the Departments of Chemistry and Laboratory Medicine & Pathology, University of Minnesota, Minneapolis, Minnesota 55455, and Department of Pharmacology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, US.
    Hargittai B, Sole NA, Groebe DR, Abramson SN, Barany G (2000) Chemical syntheses and biological activities of lactam analogues of alpha-conotoxin SI. J Med Chem 2000 43 : 4787-4792
    Abstract: Bicyclization represents an effective method for the introduction of conformational constraints into small, biologically important peptides. Several strategies have been developed for the preparation of bicyclic lactam analogues of alpha-conotoxin SI, a 13-residue peptide neurotoxin found in cone snail venom. Four analogues of the natural regioisomer of alpha-conotoxin SI were designed and synthesized, each with one of the two paired cysteines of the parent peptide being replaced by a side-chain lactam bridged glutamic acid/lysine pair. Solid-phase lactamization was studied to determine rates of formation of the two possible loops and to document the extent of dimerization and higher oligomerization. Radioligand binding assays were carried out on all synthesized peptides, including the naturally occurring two-disulfide form, in order to determine their affinities for nicotinic acetylcholine receptors (nAChRs). Replacement of the Cys(2)-Cys(7) loop of alpha-conotoxin SI with a lactam bridge resulted in complete loss of activity, whereas replacement of the Cys(3)-Cys(13) disulfide loop resulted in a approximately 60-fold reduction in affinity for one orientation and a approximately 70-fold increase in affinity for the other. The two active lactam analogues retain the selectivity exhibited by the naturally occurring peptide for the alpha/delta subunit of nAChRs, as judged by competition experiments with the curariform antagonist metocurine. PMID: 11123987, UI: 20574378

    Review on alpha conotoxins:
    Dr Arias and Blanton from the Departments of Pharmacology and Anesthesiology, School of Medicine, Texas Tech University Health Sciences Center, 79430, Lubbock, TX, USA. have written a review on alpha conotoxins.
    Arias, H.R. and Blanton, M.P. (2000) alpha-conotoxins Int J Biochem Cell Biol 32 :1017-1028
    Abstract: alpha-Conotoxins (alpha-CgTxs) are a family of Cys-enriched peptides found in several marine snails from the genus Conus. These small peptides behave pharmacologically as competitive antagonists of the nicotinic acetylcholine receptor (AChR). The data indicate that (1) alpha-CgTxs are able to discriminate between muscle- and neuronal-type AChRs and even among distinct AChR subtypes; (2) the binding sites for alpha-CgTxs are located, like other cholinergic ligands, at the interface of alpha and non-alpha subunits (gamma, delta, and varepsilon for the muscle-type AChR, and beta for several neuronal-type AChRs); (3) some alpha-CgTxs differentiate the high- from the low-affinity binding site found on either alpha/non-alpha subunit interface; and that (4) specific residues in the cholinergic binding site are energetically coupled with their corresponding pairs in the toxin stabilizing the alpha-CgTx-AChR complex. The alpha-CgTxs have proven to be excellent probes for studying the structure and function of the AChR family. PMID: 11091135, UI: 20545926

31 December 2000

    Happy festive season to you all - and good coning in 2001 :

    Elan Submits NDA for Ziconotide:

    Elan Corporation, plc announced that the company has submitted the New Drug Application (NDA) for ziconotide, a potential innovative new therapy for the treatment of intractable pain.

30 December 2000

    COGNETIX Corporation: new web site:
    COGNETIX Corporation, Salt Lake City, Utah, have released their new web site. This excellent and informative resource provides details about this private company whose mission is "to discover new methods to treat human disease or injury in order to improve quality of life". The Company's most advanced product research and development efforts are based on 'conopeptides', peptides derived from the venom of Conus species of predatory sea snails (cone shells). The site provides information about the pharmacological properties of the conopeptides (summarized in a Table)and their potential disease targets (which include Epilepsy, Pain, Local Anesthesia, Neuromuscular Blockade, Neuromuscular Disorders, Demyelinating Disorders (MS, multiple sclerosis; and SCI, spinal cord injury), and Cardiovascular and Cerebrovascular Disorders (Myocardial Ischemia, Arrhythmia, and Stroke). Among the Company's products are CGX 1007 (conantokin-G) for the treatment of epilepsy (reduction of seizures, Stage I Clinical Trials began September 30, 2000); and CGX 1160 (contulakin-G), a neurotensin receptor antagonist, targeted for reduction of short-term post-operative pain. On 5 Feb, 2000 Cognetix, Inc. formed a pain management collaboration with Elan Corporation, plc. by completing a licensing and collaboration agreement to develop and commercialize Cognetix's contulakin-G (CGX-1160) for short-term management of post-operative pain using Elan's proprietary MEDIPAD Drug Delivery System. In addition, CGX-1007 (an NMDA receptor antagonist), has potential for the prevention of neuropathic pain as do a number of mu-conotoxins (sodium channel blockers) shown to be effective in pre-clinical models of pain. At the present time (Dec. 2000) Cognetix had over 20 issued or allowed patents covering the composition of conopeptide sequences from a number of Conus species and methods to treat or diagnose various central and peripheral nervous system disorders and cardiovascular conditions (see List of Conotoxin Patents).

29 December 2000

24 December 2000

22 December 2000

    Man and Mollusc Web Resource:
    Rated by Ross Mayhew as "the most complete Malacological and Conchological links assemblage on the web": - Avril's Malacological/Conchological and Internet Resources Page provides excellent links for the on-line Molluscophile community: In agreement with Ross, I heartily recommend everyone check it out and bookmark it for further use.

21 December 2000

    Xenome granted $AUD1.6 million:
    Medica Holdings Limited, Press Release, 18 December 2000 announced :Xenome granted $1.6 million to further research and development
    Extract: Medica is pleased to announce that its most recent investee company, Xenome, has been offered a $1.6 million grant by the Industry Research and Development (IR&D) Board under AusIndustry's R&D Start Program. The grant represents matching funds for a project to develop novel therapeutic compounds for pain and urological disorders. Funds are contingent on certain conditions, such as execution of an Agreement satisfactory to the IR&D Board.
    Xenome has licensed a large portfolio of novel venom-based molecules from the University of Queensland and is systematically identifying their pharmacological activity and potential as new therapeutics.
    One significant lead compound acts on a key protein in the central nervous system (CNS) which may lead to novel treatment for CNS disorders such as depression and peripheral conditions such as pain and urinary incontinence.
    Xenome intends to utilise the grant funds to optimise the pharmacological activity of the molecules and conduct preclinical testing.

13 December 2000

    Superior clinical utility suggested for AM336 relative to ziconotide:
    At the December meeting of the Australiasian Society of Clinical and Experimental Pharmacologists and Toxicologists (ASCEPT) [Abstract P 1.11, Monday 4 December, 2000], Newcastle, Australia, Dr. M.T. Smith and coworkers presented a poster entitled:
    "LACK OF CROSS-TOLERANCE BETWEEN INTRATHECAL AM336 AND INTRAVENOUS MORPHINE IN CONTRAST TO THE MARKED CROSS-TOLERANCE BETWEEN ZICONOTIDE AND MORPHINE".
    MT Smith (1), FB Ross (1), R Lewis (2), JB Kurek (3) & PJ Cabot (1), (1) School of Pharmacy, Univ of Qld, Qld, 4072, (2) Centre for Drug Design and Development, Univ of Qld, Qld 4072, (3) AMRAD Operations, Vic 3121
    Abstract: The w-conopeptides, AM336 and ziconotide are potent inhibitors of N-type calcium channels and are currently in clinical development as novel analgesic agents for the alleviation of severe pain in patients that have failed to respond adequately to strong opioids such as morphine. As many of these patients have been treated with morphine, it is important to evaluate whether cross-tolerance occurs between these conopeptides and morphine. Therefore, this study was designed to quantify the extent of cross-tolerance between intrathecal (it) AM336 and intravenous (iv) morphine relative to that for ziconotide (it) and morphine (iv) in adult male Sprague-Dawley rats with chronic inflammatory pain. Hindpaw inflammation was induced by intra-plantar injection of Freund's Complete Adjuvant (FCA, 0.15 mL) whilst rats were under brief 3% is oflurane: 97% oxygen inhalational anaesthesia. Peptides (or vehicle) were administered via a chronically implanted polyethylene cannula inserted intrathecally between L5 and L6 and exteriorized at the base of the neck. Antinociception was quantified using the paw pressure test (PPT). On day 5 post-FCA, morphine-naïve FCA-treated rats received acute bolus doses of AM336 (0.067 nmol, it) or ziconotide (0.022, 0.059 nmol, it) in a volume of 10 mL followed by a 15 mL saline flush; antinociception was quantified for 24 h post-dosing. Rats then received a chronic infusion of morphine (10 mg/24 h) via a jugular vein cannula until rats were tolerant to its antinociceptive effects (4 days). Following a 24 h washout infusion of iv saline, rats then received a 2 nd bolus intrathecal dose of the same peptide given initially, to quantify whether the induction of morphine tolerance had altered the antinociceptive potency of subsequently administered AM336 (it) or ziconotide (it). The extent of cross-tolerance between AM336 (it) and morphine (iv) was low and not significantly different from that observed for intrathecal vehicle (150 mM lactate buffer, pH 4.5) administered before and after a chronic 7-day intrathecal infusion of vehicle. In contrast, marked cross-tolerance was found between intrathecal ziconotide and morphine. This apparently differential effect of morphine tolerance on the antinociceptive effects of subsequently administered intrathecal AM336 and ziconotide, suggests that these two conopeptides interact with different subtypes of the N-type calcium channel in the spinal cord. Furthermore, our findings suggest that AM336 may have superior clinical utility relative to ziconotide. See also Smith et al 2000 Pain. 96:119-127.

12 December 2000

10 December 2000

    3-D Structure of w-Contoxin TxVII:
    Kobayashi K, Sasaki T, Sato K, Kohno T.(2000) Three-Dimensional Solution Structure of omega-Conotoxin TxVII, an L-Type Calcium Channel Blocker. Biochemistry 39:14761-14767.
    Abstract: We determined the three-dimensional structure of omega-conotoxin TxVII, a 26-residue peptide that is an L-type calcium channel blocker, by (1)H NMR in aqueous solution. Twenty converged structures of this peptide were obtained on the basis of 411 distance constraints obtained from nuclear Overhauser effect connectivities, 20 torsion angle constraints, and 21 constraints associated with hydrogen bonds and disulfide bonds. The root-mean-square deviations about the averaged coordinates of the backbone atoms (N, C(alpha), C, and O) and all heavy atoms were 0.50 +/- 0.09 A and 0.99 +/- 0.13 A, respectively. The structure of omega-conotoxin TxVII is composed of a triple-stranded antiparallel beta-sheet and four turns. The three disulfide bonds in omega-conotoxin TxVII form the classical cystine knot motif of toxic or inhibitory polypeptides. The overall folding of omega-conotoxin TxVII is similar to those of the N-type calcium channel blockers, omega-conotoxin GVIA and MVIIA, despite the low amino acid sequence homology among them. omega-Conotoxin TxVII exposes many hydrophobic residues to a certain surface area. In contrast, omega-conotoxin GVIA and MVIIA expose basic residues in the same way as omega-conotoxin TxVII. The channel binding site of omega-conotoxin TxVII is different from those of omega-conotoxin GVIA and MVIIA, although the overall folding of these three peptides is similar. The gathered hydrophobic residues of omega-conotoxin TxVII probably interact with the hydrophobic cluster of the alpha(1) subunit of the L-type calcium channel, which consists of 13 residues located in segments 5 and 6 in domain III and in segment 6 in domain IV.

    w-Contoxins MVIIA and CVID in conscious rabbits:
    Wright, C.E., Robertson, A.D., Whorlow, S.L. and Angus, J.A. (2000) Cardiovascular and autonomic effects of omega-conotoxins MVIIA and CVID in conscious rabbits and isolated tissue assays. Br J Pharmacol. 131: 1325-1336.
    Abstract: The effects of a novel N-type voltage-operated calcium channel antagonist, omega-conotoxin CVID, were compared with omega-conotoxin MVIIA on sympathetic-evoked activation of right atria (RA), small mesenteric arteries (MA) and vasa deferentia (VD) isolated from the rat. Their effects were also compared on blood pressure and cardiovascular reflexes in conscious rabbits. The pIC(50) values for MVIIA and CVID, respectively, for inhibiting sympathetic-evoked responses were equivalent in RA (8.7 and 8.7) and VD (9.0 and 8.7); however, in MA the values were 8.4 and 7.7. The cardiac to vascular (RA/MA) potency ratios, antilog (plog RA - plog MA), for MVIIA and CVID were 2 and 10. The offset rates for CVID and MVIIA were rapid, and peptide reapplication caused rapid onset of blockade, suggesting limited desensitization. In the conscious rabbit, CVID and MVIIA (100 mug kg(-1) i.v.) caused a similar fall in blood pressure and a tachycardia that rapidly reached maximum. Both peptides decreased the vagal- and sympathetic-mediated components of the baroreflex, but had no effect on the vagal nasopharyngeal reflex. The orthostatic reflex to 90 degrees tilt was blocked by MVIIA with sustained postural hypotension for >/=90 min after administration. In contrast, CVID caused postural hypotension at 30 min which recovered rapidly. Neither CVID nor MVIIA (3 mug kg(-1) i.t.) significantly altered cardiovascular variables or autonomic reflexes. In conclusion, CVID appears to be relatively weak at inhibiting the reflex response to tilt consistent with its weaker inhibition of rat mesenteric artery constriction to perivascular nerve stimulation. This may point to subtype N-type calcium channel selectivity.

    Peptide toxins and small-cell lung carcinoma :
    Sher, E., Giovannini, F., Boot, J. and Lang, B. (2000) Peptide neurotoxins, small-cell lung carcinoma and neurological paraneoplastic syndromes. Biochimie 82: 927-936.
    Abstract: Peptide neurotoxins isolated from the venom of snakes, spiders and snails have represented invaluable tools for the identification and characterisation of membrane ion channels and receptors in vertebrate cells, including human neurons. We here report on the use of these toxins for the characterisation of membrane ion channels and receptors expressed by one of the most aggressive human cancers, small-cell lung carcinoma. This tumour shares many properties with other neuro-endocrine cell types, including the ability of firing action potentials and release hormones in a calcium-dependent manner. Toxins such as alpha-bungarotoxin and omega-conotoxins, among others, have been successfully used to characterise neuronal nicotinic receptors and voltage-dependent calcium channels, respectively, in human small-cell lung carcinoma cells. These receptors and ion channels are not only crucial for the growth of this specific tumour, but also represent autoantigens against which cancer patients build an autoimmune response. Although the aim of this autoimmune response is eventually the destruction of the cancer cells, the circulating antibodies cross-react with similar ion channels and receptors present in normal neurons or other cells, causing a number of different paraneoplastic diseases, the best characterised of which is the Lambert-Eaton myasthenic syndrome. Conotoxin-based radioimmunoassays have become an invaluable tool for the diagnosis and follow up of these paraneoplastic disorders and could represent a step forward in the early diagnosis of small-cell lung carcinoma itself.

    Ziconotide - evaluation for chronic pain:
    Jain, K.K.(2000) An evaluation of intrathecal ziconotide for the treatment of chronic pain. Expert Opin Investig Drugs 9:2403-2410.
    Abstract: Ziconotide, the synthetic form of cone snail peptide varpi-conotoxin MVIIA, is a neurone-specific N-type calcium channel blocker with an analgesic and neuroprotective effect. Intrathecal ziconotide has been recommended for approval by the FDA for the management of chronic pain. Spinally administered ziconotide produces analgesia by blocking neurotransmitter release from primary nociceptive afferents and prevents the propagation of pain signals to the brain. It has an advantage over intrathecal morphine in that there is no development of tolerance after prolonged use. Systemic toxicity is considerably reduced by administration of smaller doses intrathecally and selective delivery to the site of action in the nervous system. Nevertheless, there are neurological adverse effects due to delay in clearance of ziconotide from the neural tissues. Overall, ziconotide has a favourable risk/benefit ratio with advantages over several currently available intrathecal therapies for pain.

    See also:

    Wang, Y.X., Gao, D., Pettus, M., Phillips, C. and Bowersox, S.S. (2000) Interactions of intrathecally administered ziconotide, a selective blocker of neuronal N-type voltage-sensitive calcium channels, with morphine on nociception in rats. Pain 84:271-281.

    Atanassoff, P.G., Hartmannsgruber, M.W., Thrasher, J., Wermeling, D., Longton, W., Gaeta, R., Singh, T., Mayo, M., McGuire, D. and Luther, R.R. (2000) Ziconotide, a new N-type calcium channel blocker, administered intrathecally for acute postoperative pain.Reg Anesth Pain Med. 25:274-278

    Wang, Y.X., Pettus, M., Gao, D., Phillips, C. and Scott Bowersox S. (2000) Effects of intrathecal administration of ziconotide, a selective neuronal N-type calcium channel blocker, on mechanical allodynia and heat hyperalgesia in a rat model of postoperative pain.Pain 84: 151-158.

    Gagan Mahajan, M.D. reporting on a paper by : Fellow, UC Davis Peter G. Atanassoff, Maximillian W.B. Harmannsgruber, James Thrasher, Dan Wermeling William Longton, Raymond Gaeta, Tej Singh, Martha Nayo, Dawn McGuire, and Robert Luther, Ziconotide, A New N-Type Calcium Channel Blocker, Administered Intrathecally for Postoperative Pain . Regional Anesthesia and Pain Medicine 25 (3); 2000

    Review: N-type calcium channel blockers as analgesic agents:
    Cox, B.(2000) Calcium channel blockers and pain therapy. Curr Rev Pain 4: 488-498.

    Abstract:This review focuses on the advances in the development of N-type calcium channel blockers as analgesic agents over the last 2 years. Firstly, it highlights the clinical progress with SNX-111 (Ziconotide; Elan Pharmaceuticals, Smithfield, RI) and then secondly, it outlines the various approaches being taken by researchers to design orally active, selective, small molecule modulators without the perceived disadvantages associated with SNX-111.

1 December 2000



Continued in What's new in 2000
See also : What's new in 1999

What's new in 1998
What's New in 1997 and What's New in 1996

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