Snake Venom Research

Snake bite is a result of an unfortunate accidental interaction between a snake and a human victim. It is the single most important toxin-related injury, causing substantial mortality in many parts of the Africa, Asia, and the Americas. A World Health Organization-funded study estimated about 8,000 cases of snakebite with over 20% mortality in Bangladesh annually. A medically important land snake in Bangladesh includes the krait, cobras, and vipers. Medically important snake species are the ones that fall into one of the three categories: bite usually causes death or disability. Snake venom is highly modified saliva (Reptile Venom Research) that is produced by special glands) of certain species of snakes. The glands which secrete the zootoxin are a modification of the parotid salivary gland of other vertebrates, and are usually situated on each side of the head below and behind the eye, encapsulated in a muscular sheath. The glands have large alveoli in which venom is stored before ...

A B S T R A C T A paradigm of venom research is adaptive evolution of toxins as part of a predator-prey chemical arms race. This study examined differential co-factor dependence, variations relative to dietary preference, and the impact upon relative neutralisation by antivenom of the procoagulant toxins in the venoms of a clade of Australian snakes. All genera were characterised by venoms rich in factor Xa which act upon endogenous prothrombin. Examination of toxin sequences revealed an extraordinary level of conservation, which indicates that adaptive evolution is not a feature of this toxin type. Consistent with this, the venoms did not display differences on the plasma of different taxa. Examination of the prothrombin target revealed endogenous blood proteins are under extreme negative selection pressure for diversification, this in turn puts a strong negative selection pressure upon the toxins as sequence diversification could result in a drift away from the target. Thus this study reveals that adaptive evolution is not a consistent feature in toxin evolution in cases where the target is under negative selection pressure for diversification. Consistent with this high level of toxin conservation, the antivenom showed extremely high-levels of cross-reactivity. There was however a strong statistical correlation between relative degree of phospholipid-dependence and clotting time, with the least dependent venoms producing faster clotting times than the other venoms even in the presence of phospholipid. The results of this study are not only of interest to evolutionary and ecological disciplines, but also have implications for clinical toxinology.

The molecular origin of waglerin peptides has remained enigmatic despite their industrial application in skin cream products to paralyse facial muscles and thus reduce the incidence of wrinkles. Here we show that these neurotoxic peptides are the result of de novo evolution within the prepro region of the C-type natriuretic peptide gene in Tropidolaemus venoms, at a site distinct from the domain encoding for the natriuretic peptide. It is the same region that yielded the azemiopsin peptides from Azemiops feae, indicative of a close relationship of this toxin gene between these two genera. The precursor region for the molecular evolution is a biodiversity hotspot that has yielded other novel bioactive peptides with novel activities. We detail the diversity of components in this and other species in order to explore what characteristics enable it to be such a biodiscovery treasure trove. The unusual function of Tropidolaemus venoms may have been selected for due to evolutionary pressures brought about by a high likelihood of prey escape.

The Baja California Peninsula has over 250 islands and islets with many endemic species. Among them, rattlesnakes are the most numerous but also one of the least studied groups. The study of island rattlesnake venom could guide us to a better understanding of evolutionary processes and the description of novel toxins. Crotalus helleri caliginis venom samples were analyzed to determine possible ontogenetic variation with SDS-PAGE in one and two dimensions and with RP-HPLC. Western Blot, ELISA, and amino-terminal sequencing were used to determine the main components of the venom. The biological and biochemical activities demonstrate the similarity of C. helleri caliginis venom to the continental species C. helleri helleri, with both having low proteolytic and phospholipase A2 (PLA2) activity but differing due to the absence of neurotoxin (crotoxin-like) in the insular species. The main components of the snake venom were metalloproteases, serine proteases, and crotamine, which was the most abundant toxin group (30–35% of full venom). The crotamine was isolated using size-exclusion chromatography where its functional effects were tested on mouse phrenic nerve–hemidiaphragm preparations in which a significant reduction in muscle twitch contractions were observed. The two Mexican antivenoms could neutralize the lethality of C. helleri caliginis venom but not the crotamine effects.

This chapter reveals the vital role of Fannie Eleanor Williams in the field of medical science in Australia. It argues that Williams, as a bacteriologist and serologist from the early days in Adelaide to her long career at the Walter and  Eliza  Hall  Institute,  Melbourne,  should  be  more  highly  recognised  as  a leader in  her  research,  laboratory  management  and  mentoring.  Although  her contribution to medical science has been undervalued, she was the first female to  undertake  some  of  her  activities and in doing so led the way for other women. This  leadership  role  has  been made invisible as a result of historians’ patriarchal  presumptions  about  women’s  roles  and  work.  The  chapter  rectifies some of the misconceptions within the historiography of Australian science that have obscured Williams’  leadership.

Hyaluronidase is ubiquitous enzyme in snake venoms components, known originally as "spreading factor" because they cleave hyaluronan found in the extracellular matrix (E.C.M) of connective tissue, facilitating toxin diffusion into the tissue and blood circulation of the prey/victims. The purification procedure of a hyaluronidase from Naja melanoleuca venom is described. It involves basically size exclusion chromatography on Sephadex G-75 at PH 6.0, followed by re-chromatography of active fractions on ion exchange chromatography using DEAE-cellulose. The specific activity of purified enzyme was 0.25 TRU/mg against 0.03 TRU/mg for the crude venom, representing 8.62 purification fold. The purified hyaluronidase has molecular weight of approximately 54 KDa on SDS-PAGE. The enzyme had optimal pH 6 and temperature 38 0 C respectively. Its KM was found to be 0.381×10-3 mg/min at 38 0 C. This research showed that N. melanoleuca hyaluronidase exhibited high affinity for hyaluronic acid.

Venoms can deleteriously affect any physiological system reachable by the bloodstream, including directly interfering with the coagulation cascade. Such coagulopathic toxins may be anticoagulants or procoagulants. Snake venoms are unique in their use of procoagulant toxins for predatory purposes. The boomslang (Dispholidus typus) and the twig snakes (Thelotornis species) are iconic African snakes belonging to the family Colubridae. Both species produce strikingly similar lethal procoagulant pathologies. Despite these similarities, antivenom is only produced for treating bites by D. typus, and the mechanisms of action of both venoms have been understudied. In this study, we investigated the venom of D. typus and T. mossambicanus utilising a range of proteomic and bioactivity approaches, including determining the procoagulant properties of both venoms in relation to the human coagulation pathways. In doing so, we developed a novel procoagulant assay, utilising a Stago STA-R Max analys...

The genus Trimeresurus comprises a group of venomous pitvipers endemic to Southeast Asia and the Pacific Islands. Of these, Trimeresurus insularis, the White-lipped Island Pitviper, is a nocturnal, arboreal species that occurs on nearly every major island of the Lesser Sunda archipelago. In the current study, venom phenotypic characteristics of T. insularis sampled from eight Lesser Sunda Islands (Flores, Lembata, Lombok, Pantar, Sumba, Sumbawa, Timor, and Wetar) were evaluated via SDS-PAGE, enzymatic activity assays, fibrinogenolytic assays, gelatin zymography, and RP-HPLC, and the Sumbawa sample was characterized by venomic analysis. For additional comparative analyses, venoms were also examined from several species in the Trimeresurus complex, including T. borneensis, T. gramineus, T. puniceus, T. purpureomaculatus, T. stejnegeri, and Protobothrops flavoviridis. Despite the geographical isolation, T. insularis venoms from all eight islands demonstrated remarkable similarities in gel electrophoretic profiles and RP-HPLC patterns, and all populations had protein bands in the mass ranges of phosphodiesterases (PDE), l-amino acid oxidases (LAAO), P–III snake venom metalloproteinases (SVMP), serine proteases, cysteine-rich secretory proteins (CRISP), phospholipases A2 (PLA2), and C-type lectins. An exception was observed in the Lombok sample, which lacked protein bands in the mass range of serine protease and CRISP. Venomic analysis of the Sumbawa venom also identified these protein families, in addition to several proteins of lesser abundance (<1%), including glutaminyl cyclase, aminopeptidase, PLA2 inhibitor, phospholipase B, cobra venom factor, 5′-nucleotidase, vascular endothelial growth factor, and hyaluronidase. All T. insularis venoms exhibited similarities in thrombin-like and PDE activities, while significant differences were observed for LAAO, SVMP, and kallikrein-like activities, though these differences were only observed for a few islands. Slight but noticeable differences were also observed with fibrinogen and gelatin digestion activities. Trimeresurus insularis venoms exhibited overall similarity to the other Trimeresurus complex species examined, with the exception of P. flavoviridis venom, which showed the greatest overall differentiation. Western blot analysis revealed that all major T. insularis venom proteins were recognized by Green Pitviper (T. albolabris) antivenom, and reactivity was also seen with most venom proteins of the other Trimeresurus species, but incomplete antivenom–venom recognition was observed against P. flavoviridis venom proteins. These results demonstrate significant conservation in the venom composition of T. insularis across the Lesser Sunda archipelago relative to the other Trimeresurus species examined.

Snake bite is a result of an unfortunate accidental interaction between a snake and a human victim. It is the single most important toxin-related injury, causing substantial mortality in many parts of the Africa, Asia, and the Americas. A World Health Organization-funded study estimated about 8,000 cases of snakebite with over 20% mortality in Bangladesh annually. A medically important land snake in Bangladesh includes the krait, cobras, and vipers. Medically important snake species are the ones that fall into one of the three categories: bite usually causes death or disability. Snake venom is highly modified saliva (Reptile Venom Research) that is produced by special glands) of certain species of snakes. The glands which secrete the zootoxin are a modification of the parotid salivary gland of other vertebrates, and are usually situated on each side of the head below and behind the eye, encapsulated in a muscular sheath. The glands have large alveoli in which venom is stored before ...