Coral Snake Research Articles

Pressure-Immobilization Bandages Delay Toxicity in a Porcine Model of Eastern Coral Snake ( Micrurus fulvius fulvius) Envenomation

Pressure-immobilization bandages are used in countries where neurotoxic snake envenomations are common. They impede lymphatic egress from the bite site and delay systemic venom toxicity. The effectiveness of these devices has not been evaluated in coral snake envenomations. We investigated the efficacy of pressure-immobilization bandages in delaying the onset of systemic toxicity in a porcine model of coral snake envenomation. A randomized controlled trial of pressure-immobilization bandages was conducted in a university animal care center. Subjects were 12 anesthetized, spontaneously breathing pigs, ranging from 9.1 to 11.4 kg. After injection with 10 mg of Micrurus fulvius fulvius venom in the subcutaneous tissue of the distal foreleg, subjects were randomized to receive no treatment or application of a pressure-immobilization bandage at 1 minute after injection. Treated animals had elastic bandages applied to the extremity and splinting for immobilization. Vital signs and quality of respirations were recorded. Outcome was the onset of respiratory failure or survival to 8 hours. Necropsies and histologic analysis of the envenomation site was performed. One animal from each group was removed because of the discovery of pre-existing respiratory pathology. Four of 5 pigs in the treatment group survived to 8 hours, but none in the control group survived. Mean time to onset of respiratory compromise was 170.4 +/- 33.3 minutes in the control group. None of the pigs had histologic changes at the envenomation site consistent with ischemia or pressure-related injury. Pressure-immobilization bandages delayed the onset of systemic toxicity in our porcine model of M fulvius envenomation.

A fish prey found in the coral snake Micrurus alleni (Serpentes: Elapidae) in Costa Rica

A fish prey found in the coral snake Micrurus alleni (Serpentes: Elapidae) in Costa Rica. The presence of a small specimen of the swamp eel Synbranchus marmoratus (84 mm total length) in the stomach contents of an adult coral snake Micrurus alleni with 692 mm total length from the Caribbean versant of Costa Rica is reported. This eel was swallowed headfirst.

Biological and enzymatic activities of Micrurus sp. (Coral) snake venoms

The venoms of Micrurus lemniscatus carvalhoi, Micrurus frontalis frontalis, Micrurus surinamensis surinamensis and Micrurus nigrocinctus nigrocinctus were assayed for biological activities. Although showing similar liposome disrupting and myotoxic activities, M. frontalis frontalis and M. nigrocinctus nigrocinctus displayed higher anticoagulant and phospholipase A 2 (PLA 2) activities. The latter induced a higher edema response within 30 min. Both venoms were the most toxic as well. In the isolated chick biventer cervicis preparation, M. lemniscatus carvalhoi venom blocked the indirectly elicited twitch-tension response (85±0.6% inhibition after a 15 min incubation at 5 μg of venom/mL) and the response to acetylcholine (ACh; 55 or 110 μM), without affecting the response to KCl (13.4 mM). In mouse phrenic nerve-diaphragm preparation, the venom (5 μg/mL) produced a complete inhibition of the indirectly elicited contractile response after 50 min incubation and did not affect the contractions elicited by direct stimulation. M. lemniscatus carvalhoi inhibited 3H- l-glutamate uptake in brain synaptosomes in a Ca 2+-, but not time, dependent manner. The replacement of Ca 2+ by Sr 2+ and ethylene glycol-bis(β-aminoethyl ether) (EGTA), or alkylation of the venom with p-bromophenacyl bromide (BPB), inhibited 3H- l-glutamate uptake. M. lemniscatus carvalhoi venom cross-reacted with postsynaptic α-neurotoxins short-chain (antineurotoxin-II) and long-chain (antibungarotoxin) antibodies. It also cross-reacted with antimyotoxic PLA 2 antibodies from M. nigrocinctus nigrocinctus (antinigroxin). Our results point to the need of catalytic activity for these venoms to exert their neurotoxic activity efficiently and to their components as attractive tools for the study of molecular targets on cell membranes.

Micrurus ibiboboca (Serpentes, Elapidae) is not a Guiana Shield Species

( ) Coral snakes (Micrurus) are a diverse group of Neotropical squamates. Similarities in morphology and coloration can make identification difficult, especially in areas of species sympatry. Species with triad-type coloration, approximately 30% of all Micrurus species, are among the most difficult to identify. Micrurus ibiboboca Merrem, 1820 is an east Brazilian species with triad-type coloration. There are also reports of M. ibiboboca from the Guiana region, in Guyana, French Guiana and Surinam. In a recent revision of the genus Micrurus, Roze (1996) stated that “isolated populations [of M. ibiboboca] are probably also found in Suriname and French Guiana”, although the accompanying map of the species’ distribution shows no records from north of the Amazon. Roze’s distribution list by countries includes M. ibiboboca in the Surinam list, but not in the French Guiana list. In publications prior to 1996, Roze did not mention M. ibiboboca as occurring in French Guiana or Surinam (Roze 1967, 1983). Furthermore Roze (1996) suggested that the Guianan specimens of M. ibiboboca may really be M. isozonus. Other authors have reported the occurrence of M. ibiboboca in the Guiana region. Abuys

Efficacy of a Pressure-Immobilization bandage in delaying the onset of systemic toxicity in a porcine model of eastern coral snake (Micrurus fulvius) envenomation

Study objectives: Pressure-immobilization bandages (PIBs) are first-aid devices that are used in foreign regions where neurotoxic elapid envenomations are common. These devices are theorized to impede lymphatic return to the central circulation, thereby sequestering venom at the bite site and delaying systemic toxicity, which allows additional time to provide the victim with definitive care in the form of antivenom and advanced airway management. Coral snakes are New World elapids with primarily neurotoxic venoms. PIB use has never been formally examined in coral snake envenomations. We evaluate the efficacy of these devices in delaying the onset of systemic toxicity in a porcine model of Micrurus fulvius envenomation. Methods: The study design was a randomized, controlled trial of PIBs in a porcine model of M fulvius envenomation. The setting was a university animal laboratory. Subjects were 12 pigs, ranging from 9.1 to 11.4 kg. The animals were sedated, intubated, and anesthetized. Volatile anesthesia was maintained by animal care technicians at a level to ensure animal comfort and that all pigs were breathing spontaneously. Lyophilized venom was obtained from Natural Toxins Research Center (Kingsville, TX) and resuspended in pure water at a concentration of 10 mg/mL. The lethal dose of M fulvius venom in a human has been estimated at 5 mg, and the venom yield of a large snake can be 20 mg. We chose a 10-mg dose to ensure that all animals would develop severe toxicity during the study. The subjects were injected with 10 mg of M fulvius venom in the subcutaneous tissue of the left distal foreleg. Immediately after injection, the subjects were randomized to either receive a PIB 1 minute after envenomation or to have no treatment. The PIB consisted of an elastic bandage applied to the entire extremity at a pressure such that a finger could be easily passed under. The same operator applied all bandages. Aluminum and foam splints were then loosely taped on either side to immobilize the extremity. Pulse rate, respiratory rate, pulse oximetry, and quality of respirations were recorded at 10-minute intervals. The primary endpoint was survival to 8 hours, and groups were compared using χ 2 analysis. Groups were also compared with respect to time to onset of systemic toxicity in the form of respiratory compromise, and total time of survival. A veterinary pathologist performed necropsies on all animals, and the histology of the envenomation site was examined. One animal from each group was removed because of the discovery of preexisting respiratory pathology. Results: Four of 5 pigs in the treatment group survived to 8 hours, but none in the control group did ( P =.0036). Time to onset of signs of respiratory compromise was 170±33.3 minutes in the control group. Two pigs in the treatment group showed signs of respiratory compromise before 8 hours, 1 at 310 minutes and 1 at 460 minutes. One of these subjects did survive to 8 hours. None of the pigs had histologic changes at the envenomation site consistent with ischemic or pressure-related injury. Conclusion: Pressure immobilization bandages were effective in delaying the onset of systemic venom toxicity in this model of M fulvius envenomation. According to this study, the use of PIBs can be recommended as initial treatment in human envenomations by coral snakes.

Feeding behavior and venom toxicity of coral snake Micrurus nigrocinctus (Serpentes: Elapidae) on its natural prey in captivity

The feeding behavior and venom toxicity of the coral snake Micrurus nigrocinctus (Serpentes: Elapidae) on its natural prey in captivity were investigated. Coral snakes searched for their prey (the colubrid snake Geophis godmani) in the cages. Once their preys were located, coral snakes stroke them with a rapid forward movement, biting predominantly in the anterior region of the body. In order to assess the role of venom in prey restraint and ingestion, a group of coral snakes was ‘milked’ in order to drastically reduce the venom content in their glands. Significant differences were observed between snakes with venom, i.e., ‘nonmilked’ snakes, and ‘milked’ snakes regarding their behavior after the bite. The former remained hold to the prey until paralysis was achieved, whereas the latter, in the absence of paralysis, moved their head towards the head of the prey and bit the skull to achieve prey immobilization by mechanical means. There were no significant differences in the time of ingestion between these two groups of coral snakes. Susceptibility to the lethal effect of coral snake venom greatly differed in four colubrid species; G. godmani showed the highest susceptibility, followed by Geophis brachycephalus, whereas Ninia psephota and Ninia maculata were highly resistant to this venom. In addition, the blood serum of N. maculata, but not that of G. brachycephalus, prolonged the time of death of mice injected with 2 LD 50s of M. nigrocinctus venom, when venom and blood serum were incubated before testing. Subcutaneous injection of coral snake venom in G. godmani induced neurotoxicity and myotoxicity, without causing hemorrhage and without affecting heart and lungs. It is concluded that (a) M. nigrocinctus venom plays a role in prey immobilization, (b) venom induces neurotoxic and myotoxic effects in colubrid snakes which comprise part of their natural prey, and (c) some colubrid snakes of the genus Ninia present a conspicuous resistance to the toxic action of M. nigrocinctus venom.

Cloning and characterization of a basic phospholipase A 2 homologue from Micrurus corallinus (coral snake) venom gland

During the cloning of abundant cDNAs expressed in the Micrurus corallinus coral snake venom gland, several putative toxins, including a phospholipase A 2 homologue cDNA (clone V2), were identified. The V2 cDNA clone codes for a potential coral snake toxin with a signal peptide of 27 amino acid residues plus a predicted mature protein with 119 amino acid residues. The deduced protein is highly similar to known phospholipases A 2, with seven deduced S–S bridges at the same conserved positions. This protein was expressed in Escherichia coli as a His-tagged protein that allowed the rapid purification of the recombinant protein. This protein was used to generate antibodies, which recognized the recombinant protein in Western blot. This antiserum was used to screen a large number of venoms, showing a ubiquitous distribution of immunorelated proteins in all elapidic venoms but not in the viperidic Bothrops jararaca venom. This is the first description of a complete primary structure of a phospholipase A 2 homologue deduced by cDNA cloning from a coral snake.

Interspecific patterns of species richness, geographic range size, and body size among New World venomous snakes

Many higher taxa exhibit latitudinal gradients in species richness, geographic range size, and body size. However, these variables are often interdependent, such that examinations of univariate or bivariate patterns alone may be misleading. Therefore, I examined latitudinal gradients in, and relationships between, species richness, geographic range size, and body size among 144 species of New World venomous snakes [families Elapidae (coral snakes) and Viperidae (pitvipers)]. Both lineages are monophyletic, collectively span 99° of latitude, and are extremely variable in body size and geographic range sizes. Coral snakes exhibit highest species richness near the equator, while pitviper species richness peaks in Central America. Species – range size distributions were strongly right‐skewed for both families. There was little support for Bergmann's rule or Rapoport's rule for snakes of either family, as neither body size nor range size increased significantly with latitude. However, range area and median range latitude were positively correlated above 15° N, indicating a possible “Rapoport effect” at high northern latitudes. Geographic range size was positively associated with body size. Available continental area strongly influenced range size. Comparative (phylogenetically‐based) analyses revealed that shared history is a poor predictor of range size variation within clades. Among vipers, trends in geographic range sizes may have been structured more by historical biogeography than by macroecological biotic factors.

Australian Tiger Snake (Notechis scutatus) and Mexican Coral Snake (Micruris species) Antivenoms Prevent Death from United States Coral Snake (Micrurus fulvius fulvius) Venom in a Mouse Model

Wyeth-Ayerst has discontinued production of Antivenin (Micrurus fulvius). Currently, there is no other approved coral snake antivenom available in the United States. This study was a randomized, placebo-controlled and blinded determination of the ability of a Mexican Micrurus (coral snake) antivenom and an Australian Notechis (tiger snake) antivenom to prevent lethality from a United States Micrurus fulvius fulvius venom in a mouse model. Venom dosing was based on an LD50 determined for this experiment. Our comparison groups included: (1) M. f. fulvius venom + Micrurus antivenom, (2) M. f. fulvius venom + Notechis antivenom, (3) M. f. fulvius venom + protein control, (4) 0.9% normal saline + protein control, (5) saline + Notechis antivenom, (6) saline + Micrurus antivenom. Venom dose was 5 times the determined LD50. The antivenom amounts were capable of neutralizing 10 times the venom injected (50 times the LD50). The LD50 of M. f. fulvius venom was determined to be 0.85 mg/kg. All mice in both antivenom test groups were protected from lethality for the entire 24-hour observation period. Six of the 7 mice in the venom test group died, with a survival time of 349 +/- 382 minutes (mean +/- s.d.) after the venom injection. All three groups of control mice survived the entire 24-hour observation period. Mexican Micrurus antivenom and Australian Notechis antivenom provide protection from lethality in mice envenomated with a United States M. f. filvius venom.

Small Animal Toxicology

SECTION I: TOXICOLOGIC CONCEPTS: General Toxicologic Principles, Toxicological Information Resources, Taking a Toxicologic History, Internal Management of the Acutely Poisoned Patient, Establishing a Minimum Data Base in Small Animal Poisonings, Supportive Care of the Poisoned Patient, Toxicological Decontamination, Approach to Diagnosis and Initial Treatment for the Toxicology Case, Considerations in the Pediatric/Geriatric Poisoned Patient. SECTION II: GENERAL EXPOSURES: Summary of Small Animal Poison Exposures, Adverse Drug Reactions, Common Indoor Toxins, Indoor Environmental Quality and Health, Drugs of Abuse, Hazards Associated with the Use of Herbal and Other Natural Products, Household and Garden Plants, Use of Human Poison Centers in the Veterinary Setting, Reproductive Toxicology of the Female, Companion Animal, Reproductive Toxicology of the Male Companion Animal, Antidotes for Specific Toxins. SECTION III: SPECIFIC TOXICANTS: Acetaminophen, Amphibian Toxins, Anticoagulant, Rodenticide, Arsenic, Blue-Green Algae, Bromethalin, Carbon Monoxide Poisoning, Cholecalciferol, Citrus Oils, Copper Poisoning, Cyanide, DEET, Ethylene Glycol, Miscellaneous Herbicide, Fungicide, and Nematocides, Ionophores, Iron, Antiparasitic Agents, Lead, Poisonous Lizards, Metaldehyde, Methylxanines, Mushroom Exposure, Mycotoxins, Nicotine, Non-Steriodal Anti-Inflammatories, Organochlorine Pesticides, Organophosphate and Carbamate Insecticides, Paraquat, Petroleum, Hydrocarbons, Automotive Solvents Excluding Ethylene Glycol, Pyrethrins and Pyrethroids, Venomous Snake Bites and North American Coral Snakes, Sodium Monofluoroacetate, Black Widow Spider Envenomation, Brown Spider Envenomation, Strychnine, Zinc Phosphide, Zinc Poisoning.

The snakes of Trinidad and Tobago

Scientific fact meets island folklore as Hans Boos presents more than sixty species of snakes found in the twin-island independent Caribbean nation of Trinidad and Tobago. culmination of thirty years of collecting and observing the snakes of these islands, The Snakes of Trinidad and engagingly informs readers about these often feared and misunderstood creatures. Tracing the contributions of scientists to the evolving taxonomy of the islands' reptiles, Boos describes each unique species of snake found on the two islands, including local names from two centuries back. Species accounts come complete with tales--both documented and apocryphal--of human encounters with the more dangerous island snakes. Forty-eight color photographs and fifty black-and-white photographs and pieces of line art, most by the author, illustrate the text and aid in identification. While tiny Tobago is mercifully devoid of poisonous snakes, Trinidad hosts four venomous species, including coral snakes and the notorious bushmaster. Boos refutes many of the myths about these deadly but usually nonaggressive snakes with information about their habits and behavior. He also writes about the giant anaconda and the boa constrictor, about which many half-truths and fictions abound. All snakes bite, but only a few species are venomous. Boos gives information about what to do--and what not to do--in the event of a bite and discusses intriguing folk medicine cures, such as the Belgian Black Stone, sure to work only if a bite was harmless to begin with. The Snakes of Trinidad and will find an enthusiastic audience among herpetologists, ecologists, and other scientists concerned about the snakes and wildlife of Trinidad and Tobago, the Caribbean, and South America. It will also appeal to general readers interested in snakes and in Caribbean folklore.

SOUTH AMERICAN COLUBRID ENVENOMATIONS

Most snakebites in South America are caused by pitvipers (Bothrops, Crotalus and Lachesis spp.) and coral snakes (Micrurus spp.), with less serious accidents caused by colubrids. Rear-fanged species are responsible for most colubrid envenomations, the principal genera involved being Clelia, Helicops, Liophis, Philodryas, Tachymenis, and Thamnodynastes. The hands, feet and upper and lower limbs are bitten most frequently. Most envenomations are mild, involving mainly local pain, edema and ecchymosis. Systemic envenomation (altered whole blood clotting time, systemic bleeding, shock, and renal failure) is rare and only one fatality suspected to have been caused by a colubrid (P. olfersii in Brazil) has been recorded. Treatment is symptomatic and supportive, and recovery is generally uneventful, with no sequelae. The similarity between the local effects of envenomations by colubrids and those produced by South American lanceheads (Bothrops spp.) has resulted in bothropic antivenom being administered in sever...

Reproductive biology of the false coral snake Oxyrhopus guibei (Colubridae) from southeastern Brazil

AbstractThe reproductive biology of the false coral snake, Oxyrhopus guibei, was studied through dissection of 496 specimens, combined with observations on captive individuals. Males mature with smaller body size than females, females attain much larger body size, and male-male combat is not expected. Clutch size ranged from 3 to 20, and was correlated with female length. Reproductive cycles in both males and females seem to be continuous, with vitellogenesis and spermatogenesis occurring throughout the year. Reproductive activity in both sexes decreased at the end of the rainy season possibly due to previous intense reproductive activity in more favorable climatic conditions. The smaller number of individuals collected at the end of the rainy season apparently occurs due to the decrease of reproductive activity of this snake.

Action of Micrurus dumerilii carinicauda coral snake venom on the mammalian neuromuscular junction

The venoms of coral snakes (mainly Micrurus species) have pre- and/or postsynaptic actions, but only a few of these have been studied in detail. We have investigated the effects of Micrurus dumerilii carinicauda coral snake venom on neurotransmission in rat isolated phrenic nerve-diaphragm muscle and chick biventer cervicis preparations stimulated directly or indirectly. M. d. carinicauda venom (5 or 10 μg/ml) produced neuromuscular blockade in rat (85–90% in 291.8±7.3 min and 108.3±13.8, respectively; n=5) and avian (95.0±2.0 min; 5 μg/ml, n=5) preparations. Neostigmine (5.8 μM) and 3,4-diaminopyridine (230 μM) partially reversed the venom-induced neuromuscular blockade in rat nerve-muscle preparations. In neither preparation did the venom depress the twitch response elicited by direct muscle stimulation. The contractures induced by acetylcholine in chick preparations were inhibited by the venom (95–100%; n=4; p<0.05). In rat preparations, the venom produced a progressive decrease in the amplitude of miniature end-plate potentials (m.e.p.ps control frequency=69.3±5.0/min and control amplitude=0.4±0.2 mV) until these were abolished. Neostigmine (5.8 μM) and 3,4-diaminopyridine (230 μM) partially antagonized this blockade of m.e.p.ps. The resting membrane potential was not altered with the venom (10 μg/ml). M. d. carinicauda venom produced dose-dependent morphological changes in indirectly stimulated mammal preparations. Twenty-five per cent of muscle fibers were affected by a venom concentration of 5 μg/ml, whilst 60.7% were damaged by 10 μg of venom/ml. In biventer cervicis preparations, the morphological changes were slower in onset and were generally characterized by undulating fibers and, to a lesser extent, by zones of disintegrating myofibrils. A venom concentration of 5 μg/ml damaged 52.2% of the fibers. These findings indicate that M. d. carinicauda venom has neurotoxic and myotoxic effects and that the neuromuscular blockade involves mainly a postsynaptic action.

Prey specificity, comparative lethality and compositional differences of coral snake venoms

Toxicities of crude venoms from 49 coral snake ( Micrurus sp.) populations, representing 15 nominal taxa, were examined in both laboratory mice and in native prey animals and compared with data gathered from two non-micrurine elapids and a crotalid, which served as outgroups. These venoms were further compared on the basis of 23 enzymatic activities. Both toxicities and enzymatic activities were analyzed with respect to natural prey preferences, as determined from stomach content analyses and literature reports. Venoms of nearly all Micrurus for which prey preferences are known, are more toxic to natural prey than to non-prey species. Except for amphisbaenians, prey are more susceptible to venoms of Micrurus that feed upon them, than to venoms of those that eat other organisms. All venoms were more toxic i.v.>i.p.>i.m. Route-specific differences in toxicity are generally greatest for preferred prey species. Cluster analyses of venom enzymatic activities resulted in five clusters, with the fish-eating M. surinamensis more distant from other Micrurus than even the crotalid, Bothrops moojeni. Ophiophagous and amphisbaenian-eating Micrurus formed two close subclusters, one allied to the outgroup species Naja naja and the other to the fossorial, ophiophagous Bungarus multicinctus. Prey preference is shown to be the most important determinant of venom composition in Micrurus.

Cross reactivity of different specific Micrurus antivenom sera with homologous and heterologous snake venoms

Coral snakes are the only Elapids in America. They are represented by three genera: Leptomicrurus, Micruroides and Micrurus, of which the latter are the most abundant and diversified group. Little is known about the biochemistry of Micrurus venoms due to low availability. Here, we present a study on the cross reactivity of different specific Micrurus antivenom with homologous and heterologous snake venoms in order to contribute to the generation of more efficient antiserum for therapeutic purposes. The three specific antisera tested, anti-Micrurus corallinus, anti-Micrurus frontalis, and anti-Micrurus spixii, as well as the bivalent anti-elapid venom sera, raised against a mixture (50% each) of Micrurus frontalis and Micrurus corallinus venoms, were assayed by Western Blot against Micrurus and non-Micrurus elapid venoms. An antisera raised against a recombinant α-neurotoxin-like protein from Micrurus corallinus venom, only reacted in Western blot with its homologous venom, indicating that this protein is specific for Micrurus corallinus coral snake.

1999 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System

There are 5000–10,000 snake envenomations annually in the United States. Fortunately, few are fatal. In this study we review the epidemiology of fatal snakebites.Native snakebite cases from the American Association of Poison Control Centers (AAPCC) National Poison Data System from 1989 to 2018 were reviewed. Additional cases that were not reported to the AAPCC were identified by reviewing Wikipedia and by searching PubMed and online news outlets using various combinations of relevant keywords.We identified 101 fatal bites from native snakes. Rattlesnakes accounted for 74 (90.2%) of the 82 deaths for which the species was known or which occurred where rattlesnakes are the only native crotalids. There were five fatalities attributed to copperheads, two due to cottonmouths, and one caused by an eastern coral snake. Males were disproportionately affected. The median age for victims was 40 years old. In cases for which data were available, many of the snake interactions were intentional, e.g. religious services, animal husbandry, and attempting to kill the snake.Death following envenomation from a native U.S. snake is unlikely, particularly if medical attention is sought promptly. Rattlesnake envenomations are more likely to be fatal than bites from other species. Intentionally engaging with a venomous snake raises the risk of incurring a fatal bite, as does concurrent alcohol or drug use. Age less than 12 years old does not appear to be a risk factor for a fatal outcome, while elderly patients may have a slightly increased risk of death.

Phylogenetic Relationships of Elapid Snakes Based on Cytochrome b mtDNA Sequences

Published molecular phylogenetic studies of elapid snakes agree that the marine and Australo–Melanesian forms are collectively monophyletic. Recent studies, however, disagree on the relationships of the African, American, and Asian forms. To resolve the relationships of the African, American, and Asian species to each other and to the marine/Australo–Melanesian clade, we sequenced the entire cytochrome b gene for 28 elapids; 2 additional elapid sequences from GenBank were also included. This sample includes all African, American, and Asian genera (except for the rare African Pseudohaje), as well as a representative sample of marine/Australo–Melanesian genera. The data were analyzed by the methods of maximum-parsimony and maximum-likelihood. Both types of analyses yielded similar trees, from which the following conclusions can be drawn: (1) Homoroselaps falls outside a clade formed by the remaining elapids; (2) the remaining elapids are divisible into two broad sister clades, the marine/Australo–Melanesian species vs the African, American, and Asian species; (3) American coral snakes cluster with Asian coral snakes; and (4) the “true” cobra genus Naja is probably not monophyletic as the result of excluding such genera as Boulengerina and Paranaja.

Cloning and expression of a potential α-neurotoxin (clone V1) from the venom gland of the coral snake Micrurus corallinus in E. coli

Cloning and expression of a potential α-neurotoxin (clone V1) from the venom gland of the coral snake Micrurus corallinus in E. coli

Cloning and Characterization of an α-Neurotoxin-Type Protein Specific for the Coral Snake Micrurus corallinus

During the cloning of abundant cDNAs expressed in the Micrurus corallinus coral snake venom gland, we cloned an α-neurotoxin homologue cDNA (nxh1). Two others isoforms were also cloned (nxh3 and nxh7, respectively). The nxh1 cDNA codes for a potential coral snake toxin with a signal peptide of 21 amino acids plus a predicted mature peptide with 57 amino acids. The deduced protein is highly similar to known toxic three-finger α-neurotoxins, with four deduced S–S bridges at the same conserved positions. This is the first cDNA coding for a three-finger related protein described so far for coral snakes. However, the predicted protein does not possess some of the important amino acids for the nicotinic acetylcholine receptor interaction. This protein was expressed in Escherichia coli as a His-tagged protein that allowed the rapid purification of the recombinant protein. This protein was used to generate antibodies which recognized the recombinant protein in Western blot and also a single band present in the M. corallinus venom, but not in the venom of 10 other Micrurus species.