Local morbidity from red-bellied black snake (Pseudechis porphyriacus, Elapidae) envenoming: Two cases and a brief review of management.

The red-bellied black snake (Pseudechis porphyriacus, Elapidae) is one of several species of venomous snakes most commonly implicated in human and domestic animal envenoming in Australia. Human systemic envenoming can present with myotoxicity that may include myoglobinuria; hemoglobinuria and intravascular hemolysis; thrombocytopenia, anticoagulant coagulopathy, and, rarely, mild cranial nerve palsies. Pseudechis porphyriacus envenoming can also feature significant local morbidity such as ecchymoses, bleeding, pain and necrosis. Some envenomed patients may develop progressive thickness necrosis independent of secondary infection, and occasionally require surgical debridement. Uncommonly, some digital envenoming may cause more severe deeper tissue pathology that justifies dermotomy and/or distal phalangeal amputation. Presented are two patients with significant local morbidity from P. porphyriacus envenoming. An 18-month old girl received a protracted envenoming on her right foot, while a 38-year old male professional zoologist was envenomed on the third digit of his right hand. Each patient experienced myotoxicity, one had anticoagulant coagulopathy, and both developed clinically significant local morbidity including persistent bleeding, ecchymoses, local necrosis and pain; each required extensive treatment and variably prolonged admission. Noted also were transiently elevated D-dimer with low-normal or normal fibrinogen levels. The progressive necrosis and subsequent chronic pathologic changes with ischemia of the latter patient's digit eventually required a dermotomy and amputation of the distal phalanx. The pediatric patient did not require extensive wound debridement, but experienced prolonged difficulty in ambulation because of slowly resolving wound discomfort. Factors that may contribute to the severity of local morbidity of P. porphyriacus envenoming are considered, and management of envenoming by this taxon is briefly reviewed.

Cross neutralization of coral snake venoms by commercial Australian snake antivenoms.

CONTEXT: Although rare, coral snake envenomation is a serious health threat in Brazil, because of the highly neurotoxic venom and the scarcely available antivenom. The major bottleneck for antivenom production is the low availability of venom. Furthermore, the available serum is not effective against all coral snake species found in Brazil. An alternative to circumvent the lack of venom for serum production and the restricted protection of the actually available antivenom would be of great value. We compared the Brazilian coral snake and mono and polyvalent Australian antivenoms in terms of reactivity and protection. METHODS: The immunoreactivity of venoms from 9 coral snakes species were assayed by ELISA and western blot using the Brazilian Micrurus and the Australian pentavalent as well as monovalent anti-Notechis, Oxyuranus and Pseudechis antivenoms. Neutralization assays were performed in mice, using 3 LD50 of the venoms, incubated for 30 minutes with 100 µL of antivenom/animal. DISCUSSION: All the venoms reacted against the autologous and heterologous antivenoms. Nevertheless, the neutralization assays showed that the coral snake antivenom was only effective against M. corallinus, M. frontalis, M. fulvius, M. nigrocinctus and M. pyrrhocryptus venoms. On the other hand, the Australian pentavalent antivenom neutralized all venoms except the one from M. spixii. A combination of anti-Oxyuranus and Pseudechis monovalent sera, extended the protection to M. altirostris and, partially, to M. ibiboboca. By adding Notechis antivenom to this mixture, we obtained full protection against M. ibiboboca and partial neutralization against M. lemniscatus venoms. CONCLUSIONS: Our findings confirm the limited effectiveness of the Brazilian coral snake antivenom and indicate that antivenoms made from Australian snakes venoms are an effective alternative for coral snake bites in South America and also in the United States were coral snake antivenom production has been discontinued.

Cross neutralization of coral snake venoms by commercial Australian snake antivenoms

Context: Although rare, coral snake envenomation is a serious health threat in Brazil, because of the highly neurotoxic venom and the scarcely available antivenom. The major bottleneck for antivenom production is the low availability of venom. Furthermore, the available serum is not effective against all coral snake species found in Brazil. An alternative to circumvent the lack of venom for serum production and the restricted protection of the actually available antivenom would be of great value. We compared the Brazilian coral snake and mono and polyvalent Australian antivenoms in terms of reactivity and protection. Methods: The immunoreactivity of venoms from 9 coral snakes species were assayed by ELISA and western blot using the Brazilian Micrurus and the Australian pentavalent as well as monovalent antiNotechis, Oxyuranus and Pseudechis antivenoms. Neutralization assays were performed in mice, using 3 LD50 of the venoms, incubated for 30 minutes with 100 mu L of antivenom/animal. Discussion: All the venoms reacted against the autologous and heterologous antivenoms. Nevertheless, the neutralization assays showed that the coral snake antivenom was only effective against M. corallinus, M. frontalis, M. fulvius, M. nigrocinctus and M. pyrrhocryptus venoms. On the other hand, the Australian pentavalent antivenom neutralized all venoms except the one from M. spixii. A combination of anti-Oxyuranus and Pseudechis monovalent sera, extended the protection to M. altirostris and, partially, to M. ibiboboca. By adding Notechis antivenom to this mixture, we obtained full protection against M. ibiboboca and partial neutralization against M. lemniscatus venoms. Conclusions: Our findings confirm the limited effectiveness of the Brazilian coral snake antivenom and indicate that antivenoms made from Australian snakes venoms are an effective alternative for coral snake bites in South America and also in the United States were coral snake antivenom production has been discontinued.

Proteomic comparisons of venoms of long-term captive and recently wild-caught Eastern brown snakes (Pseudonaja textilis) indicate venom does not change due to captivity.

UNLABELLED: Snake venom is a highly variable phenotypic character, and its variation and rapid evolution are important because of human health implications. Because much snake antivenom is produced from captive animals, understanding the effects of captivity on venom composition is important. Here, we have evaluated toxin profiles from six long-term (LT) captive and six recently wild-caught (RC) eastern brown snakes, Pseudonaja textilis, utilizing gel electrophoresis, HPLC-MS, and shotgun proteomics. We identified proteins belonging to the three-finger toxins, group C prothrombin activators, Kunitz-type serine protease inhibitors, and phospholipases A2, among others. Although crude venom HPLC analysis showed LT snakes to be higher in some small molecular weight toxins, presence/absence patterns showed no correlation with time in captivity. Shotgun proteomics indicated the presence of similar toxin families among individuals but with variation in protein species. Although no venom sample contained all the phospholipase A2 subunits that form the textilotoxin, all did contain both prothrombin activator subunits. This study indicates that captivity has limited effects on venom composition, that venom variation is high, and that venom composition may be correlated to geographic distribution. BIOLOGICAL SIGNIFICANCE: Through proteomic comparisons, we show that protein variation within LT and RC groups of snakes (Pseudonaja textilis) is high, thereby resulting in no discernible differences in venom composition between groups. We utilize complementary techniques to characterize the venom proteomes of 12 individual snakes from our study area, and indicate that individuals captured close to one another have more similar venom gel electrophoresis patterns than those captured at more distant locations. These data are important for understanding natural variation in and potential effects of captivity on venom composition.

Characterization and structural analysis of a potent anticoagulant phospholipase A2 from Pseudechis australis snake venom.

Pseudechis australis is one of the most venomous and lethal snakes in Australia. Numerous phospholipase A2 (PLA2) isoforms constitute a major portion of its venom, some of which have previously been shown to exhibit not only enzymatic, but also haemolytic, neurotoxic and anticoagulant activities. Here, we have purified a potent anticoagulant PLA2 (identified as PA11) from P. australis venom to investigate its phospholipase, anticoagulant, haemolytic and cytotoxic activities and shown that addition of 11 nM PA11 resulted in a doubling of the clotting time of recalcified whole blood. We have also demonstrated that PA11 has high PLA2 enzymatic activity (10.9 × 10(4) Units/mg), but low haemolytic activity (0.6% of red blood cells hydrolysed in the presence of 1 nM PA11). PA11 at a concentration lower than 600 nM is not cytotoxic towards human cultured cells. Chemical modification experiments using p-bromophenacyl bromide have provided evidence that the catalytic histidine of PA11 is critical for the anticoagulant activity of this PLA2. PA11 that was subjected to trypsin digestion without previous reduction and alkylation of the disulfide bonds maintained enzymatic and anticoagulant activity, suggesting that proteolysis alone cannot abolish these properties. Consistent with these results, administration of PA11 by gavage in a rabbit stasis thrombosis model increased the clotting time of recalcified citrated whole blood by a factor of four. These data suggest that PA11 has potential to be developed as an anticoagulant in a clinical setting.

Venomics of the Australian eastern brown snake (Pseudonaja textilis): Detection of new venom proteins and splicing variants.

The eastern brown snake is the predominant cause of snakebites in mainland Australia. Its venom induces defibrination coagulopathy, renal failure and microangiopathic hemolytic anemia. Cardiovascular collapse has been described as an early cause of death in patients, but, so far, the mechanisms involved have not been fully identified. In the present work, we analysed the venome of Pseudonaja textilis by combining high throughput proteomics and transcriptomics, aiming to further characterize the components of this venom. The combination of these techniques in the analysis and identification of toxins, venom proteins and putative toxins allowed the sequence description and the identification of the following: prothrombinase coagulation factors, neurotoxic textilotoxin phospholipase A2 (PLA2) subunits and "acidic PLA2", three-finger toxins (3FTx) and the Kunitz-type protease inhibitor textilinin, venom metalloproteinase, C-type lectins, cysteine rich secretory proteins, calreticulin, dipeptidase 2, as well as evidences of Heloderma lizard peptides. Deep data-mining analysis revealed the secretion of a new transcript variant of venom coagulation factor 5a and the existence of a splicing variant of PLA2 modifying the UTR and signal peptide from a same mature protein. The transcriptome revealed the diversity of transcripts and mutations, and also indicates that splicing variants can be an important source of toxin variation.

Comparative studies of the venom of a new Taipan species, Oxyuranus temporalis, with other members of its genus.

Taipans are highly venomous Australo-Papuan elapids. A new species of taipan, the Western Desert Taipan (Oxyuranus temporalis), has been discovered with two specimens housed in captivity at the Adelaide Zoo. This study is the first investigation of O. temporalis venom and seeks to characterise and compare the neurotoxicity, lethality and biochemical properties of O. temporalis venom with other taipan venoms. Analysis of O. temporalis venom using size-exclusion and reverse-phase HPLC indicated a markedly simplified "profile" compared to other taipan venoms. SDS-PAGE and agarose gel electrophoresis analysis also indicated a relatively simple composition. Murine LD50 studies showed that O. temporalis venom is less lethal than O. microlepidotus venom. Venoms were tested in vitro, using the chick biventer cervicis nerve-muscle preparation. Based on t90 values, O. temporalis venom is highly neurotoxic abolishing indirect twitches far more rapidly than other taipan venoms. O. temporalis venom also abolished responses to exogenous acetylcholine and carbachol, indicating the presence of postsynaptic neurotoxins. Prior administration of CSL Taipan antivenom (CSL Limited) neutralised the inhibitory effects of all taipan venoms. The results of this study suggest that the venom of the O. temporalis is highly neurotoxic in vitro and may contain procoagulant toxins, making this snake potentially dangerous to humans.

The effects of selected Australian snake venoms on tumour-associated microvascular endothelial cells (TAMECs) in vitro.

The effects of various viperid and elapid venoms on the cellular biology of tumour-associated microvascular endothelial cells (TAMECs) were determined in the current study using cells isolated from a rat mammary adenocarcinoma. Previous studies to determine the effects of snake venoms on endothelial cells in vitro have in the main been performed on either human umbilical vein endothelial cells (HUVECs), bovine aortic endothelial cells (BAECs) or endothelial cell lines. These cell populations are accessible and easy to maintain in culture, however, it is well established that endothelial cells display vast heterogeneity depending upon the local microenvironment of the tissue from which they are isolated. Vascular targeting agents have been isolated from a variety of snake venoms, particularly from snakes of the Viperidae family, but it is yet to be established to what extent the venoms from Australian elapids possess similar vascular targeting properties. The present study used endothelial cells (ECs) isolated from the microvasculature of a rat mammary adenocarcinoma to determine the effects of a panel of snake venoms, including viperid venoms with known apoptotic activity and elapid venoms (both exotic and indigenous to Australia), on endothelial morphology and viability, paying specific attention to apoptotic responses. Three of the five Australian snake venoms investigated in this study elicited significant apoptotic responses in ECs which were in many ways similar to responses elicited by the selected viperid venoms. This suggests that these Australian elapids may possess vascular targeting components similar to those found within viperid venoms.

Cross-neutralisation of the neurotoxic effects of Egyptian cobra venom with commercial tiger snake antivenom.

Cross-neutralisation has been demonstrated for haemorrhagic venoms including Echis spp. and Cerastes spp. and for Australia elapid procoagulant toxins. A previous study showed that commercial tiger snake antivenom (TSAV) was able to neutralise the systemic effects of the Egyptian cobra, Naja haje, in vivo but it is unclear if this was true cross-neutralisation. The aim of the current study was to determine whether TSAV can neutralise the in vitro neurotoxic effects of N. haje venom. Both Notechis scutatus (10 µg/ml) and N. haje (10 µg/ml) venoms caused inhibition of indirect (supramaximal V, 0.1 Hz, 0.2 msec.) twitches of the chick biventer cervicis nerve-muscle preparation with t(90) values (i.e. the time to produce 90% inhibition of the original twitch height) of 26 ± 1 min. (n = 4) and 36 ± 4 min.; (n = 4). This effect at 10 µg/ml was significantly attenuated by the prior addition of TSAV (5 U/ml). A comparison of the reverse-phase HPLC profiles of both venoms showed some similarities with peak elution times, and SDS-PAGE analysis elucidated comparable bands across both venoms. Further analysis using Western immunoblotting indicated TSAV was able to detect N. haje venom, and enzyme immunoassay showed that in-house biotinylated polyclonal monovalent N. scutatus antibodies were able to detect N. haje venom. These findings demonstrate cross-neutralisation between different and geographically separated snakes supporting potential immunological similarities in snake toxin groups for a large range of snakes. This provides more evidence that antivenoms could be developed against specific toxin groups to cover a large range of snakes.

Cytoskeletal rearrangements in human red blood cells induced by snake venoms: light microscopy of shapes and NMR studies of membrane function.

RBCs (red blood cells) circulating through narrow blood capillaries withstand major deformation. The mechanical and chemical stresses commonly exerted on RBCs continue to attract interest for the study of membrane structure and function. Snake venoms are lethal biochemical 'cocktails' that often contain haemotoxins, metalloproteinases, myotoxins, neurotoxins, phosphodiesterases, phospholipases and proteases. We have monitored the effects of 4 snake venoms (Pseudechis guttatus, Oxyuranus scutellatus, Notechis scutatus and Naja kaouthia) on human RBCs using NMR spectroscopy, DIC (differential interference contrast) and confocal light microscopy. RBCs underwent reproducible stomatocytosis, with unusual geographical-like indentations, spherocytosis, followed by rapid lysis. Confocal micrographs using a fluorescent dye linked to phalloidin showed that the change in morphology was associated with the aggregation of actin in the cytoskeleton. (31)P NMR saturation transfer experiments recorded transport of the univalent anion HPA (hypophosphite) on a subsecond time scale, thereby reporting on the function of capnophorin or Band 3 linked to the cytoskeleton; anion-exchange activity was substantially reduced by venom treatment. We propose a molecular-cytological hypothesis for the shape and functional changes that is different from, or supplementary to, the more 'traditional' bilayer-couple hypothesis more often used to account for similar morphological changes invoked by other reagents.

Snake venom: From fieldwork to the clinic: Recent insights into snake biology, together with new technology allowing high-throughput screening of venom, bring new hope for drug discovery.

Snake venoms are recognized here as a grossly under-explored resource in pharmacological prospecting. Discoveries in snake systematics demonstrate that former taxonomic bias in research has led to the neglect of thousands of species of potential medical use. Recent discoveries reveal an unexpectedly vast degree of variation in venom composition among snakes, from different species down to litter mates. The molecular mechanisms underlying this diversity are only beginning to be understood. However, the enormous potential that this resource represents for pharmacological prospecting is clear. New high-throughput screening systems offer greatly increased speed and efficiency in identifying and extracting therapeutically useful molecules. At the same time a global biodiversity crisis is threatening the very snake populations on which hopes for new venom-derived medications depend. Biomedical researchers, pharmacologists, clinicians, herpetologists, and conservation biologists must combine their efforts if the full potential of snake venom-derived medications is to be realized.

Identification of novel proteins from the venom of a cryptic snake Drysdalia coronoides by a combined transcriptomics and proteomics approach.

We have investigated the transcriptome and proteome of the venom of a cryptic Australian elapid snake Drysdalia coronoides. To probe into the transcriptome, we constructed a partial cDNA library from the venom gland of D. coronoides. The proteome of the venom of D. coronoides was explored by tryptic digestion of the crude venom followed by HPLC separation of the resulting peptides and MALDI-TOF/TOF mass spectrometric analysis. Importantly, the tandem MS data of the tryptic peptides of the venom not only confirmed the predicted protein sequences deduced from the transcriptome, but also added to our knowledge about the venom composition through identification of two more toxin families. Using both the approaches, we were able to identify proteins belonging to eight different snake venom protein superfamilies, namely, three-finger toxins, serine protease inhibitors, cysteine rich secretory proteins, phospholipases A(2), venom nerve growth factors, snake venom metalloproteases, vespryns, and a new family phospholipase B. We also identified three novel proteins belonging to the three-finger toxin superfamily.

Validation of a cell-based assay to differentiate between the cytotoxic effects of elapid snake venoms.

INTRODUCTION: Acanthophis genus (i.e. death adders) and the Naja genus (i.e. cobras) belong to the family elapidae. The current study compared the in vitro cytotoxicity of venoms from four Acanthophis spp. and three Naja spp. on rat aortic smooth muscle cells, A7r5, and rat skeletal muscle cells, L6. The ability of CSL death adder antivenom and SAIMR antivenom, for Acanthophis spp. and Naja spp. venom respectively, to negate the cytotoxicity was also examined. METHODS: A cell proliferation assay was used to determine cell viability following treatment with venom in the presence or absence of antivenom. Sigmoidal growth curves were obtained, and IC(50) values were determined. RESULTS: Acanthophis spp. and Naja spp. venoms produced concentration-dependent inhibition of cell proliferation in both cell lines. Naja spp. venoms were significantly more cytotoxic than the most potent Acanthophis venom (i.e. A. antarcticus) in both cell lines. Naja spp. venoms also displayed higher sensitivity in L6 cells. SAIMR antivenom significantly inhibited the cytotoxic actions of all Naja spp. venoms in both A7r5 and L6 cells. However, death adder antivenom (CSL Ltd) was unable to negate the cytotoxic effects of Acanthophis spp. venoms. DISCUSSION: Concentrations of the predominantly cytotoxic Naja spp. venoms used were approximately three times less than the predominantly neurotoxic Acanthophis spp. venoms. SAIMR antivenom was partially effective in neutralising the effects of Naja spp. venoms. Death adder antivenom (CSL Ltd) was not effective in negating the cytotoxic effects of venom from Acanthophis spp. These results indicate that the cell-based assay is suited to the examination of cytotoxic snake venoms and may be used in conjunction with organ bath experiments to pharmacologically characterise snake venoms. Furthermore, the results suggest that the use of a skeletal muscle cell line is likely to be more clinically relevant for the examination of cytotoxic snake venoms.

Proteolytic activity of Elapid and Viperid Snake venoms and its implication to digestion.

Testing whether venoms may aid in digestion of the prey, eleven snake venoms were compared for the presence of proteases and endopeptidases that function in alkaline pH conditions. In vitro experiments examined the relative protease and endopeptidase activity of the venoms, which involved combining bovine muscle and snake venom in a buffered solution, encased within dialysis tubing. This mixture was then incubated at room temperature (∼20°C) for 24hr, with constant shaking. Bicinchoninic acid (BCA) assay and ninhydrin assay were used to determine peptide and amino acid concentrations. Histological and immunohistochemical investigations using N. kaouthia venom confirmed in vitro findings. Results show that B. arietans venom generated the highest amount of protein/peptides and amino acids in the dialysates, while O. scutellatus, N. ater niger and P. textilis venom did not show any significant protein degradation under alkaline conditions. Histological examination revealed varying degrees of muscle cell damage for each of the venom investigated, and the immunohistochemical study on N. kaouthia venom showed that the venom penetrated the muscle tissue to a significant degree. In vitro assays and histological results indicate that particular venoms may possess the ability to enhance digestion of bovine muscle tissue.

The recruitment of blood coagulation factor X into snake venom gland as a toxin: the role of promoter cis-elements in its expression.

Trocarin D is a prothrombin activator from the Tropidechis carinatus venom. It is a functional and structural homologue to mammalian blood coagulation factor Xa. Trocarin D is hypothesised to have evolved from its factor X counterpart (TrFX) through gene duplication and recruitment. The genes of trocarin D and TrFX have significant sequence identities, except for insertions/deletions in their intron 1 and promoter regions. In trocarin D intron 1 region, there are three insertions and two deletions. In trocarin D promoter region, there is a novel 264 bp insertion which has potential cis-elements. This insertion is termed as Venom Recruitment/Switch Element (VERSE) and is hypothesised to account for switching the low-level constitutive expression of factor X in the liver to the high-level inducible expression of trocarin D in the venom gland. To understand the role of VERSE in the trocarin D expression, its cis-elements were characterised by luciferase assays in mammalian cell lines as well as snake venom gland cells. The ability of VERSE to drive luciferase expression is comparable to that of the trocarin D promoter. The predicted cis-elements are important in promoting expression as their mutagenesis resulted in lower luciferase expression. VERSE minimal core promoter and three novel cis-elements (two up-regulatory and one suppressor elements) were identified using deletion/site-directed mutagenesis studies. VERSE is primarily responsible for the increase of trocarin D expression. The insertions/deletions within trocarin D intron 1 need to be characterised for their role in tissue-specific and inducible expression of trocarin D.

Evolutionary origin and development of snake fangs.

Many advanced snakes use fangs-specialized teeth associated with a venom gland-to introduce venom into prey or attacker. Various front- and rear-fanged groups are recognized, according to whether their fangs are positioned anterior (for example cobras and vipers) or posterior (for example grass snakes) in the upper jaw. A fundamental controversy in snake evolution is whether or not front and rear fangs share the same evolutionary and developmental origin. Resolving this controversy could identify a major evolutionary transition underlying the massive radiation of advanced snakes, and the associated developmental events. Here we examine this issue by visualizing the tooth-forming epithelium in the upper jaw of 96 snake embryos, covering eight species. We use the sonic hedgehog gene as a marker, and three-dimensionally reconstruct the development in 41 of the embryos. We show that front fangs develop from the posterior end of the upper jaw, and are strikingly similar in morphogenesis to rear fangs. This is consistent with their being homologous. In front-fanged snakes, the anterior part of the upper jaw lacks sonic hedgehog expression, and ontogenetic allometry displaces the fang from its posterior developmental origin to its adult front position-consistent with an ancestral posterior position of the front fang. In rear-fanged snakes, the fangs develop from an independent posterior dental lamina and retain their posterior position. In light of our findings, we put forward a new model for the evolution of snake fangs: a posterior subregion of the tooth-forming epithelium became developmentally uncoupled from the remaining dentition, which allowed the posterior teeth to evolve independently and in close association with the venom gland, becoming highly modified in different lineages. This developmental event could have facilitated the massive radiation of advanced snakes in the Cenozoic era, resulting in the spectacular diversity of snakes seen today.

Twentieth century toxinology and antivenom development in Australia.

It was not until the last decade of the 19th century that an experimental approach (led by Bancroft in Queensland and Martin in Sydney and Melbourne) brought a higher plane of scientific objectivity to usher in the modern era of Australian toxinology. This Australia era, 1895-1905, coincided with and in some respects was the result of the new knowledge emerging from Europe and the Americas of the therapeutic effects of antitoxins. The subsequent systematic study of Australian venoms and toxins through to the 1930s and beyond, by Tidswell, Fairley, Ross, Kellaway and Cleland, set the foundation for Australia's leading reputation in venom research. As elsewhere, this development was to revolutionise the medical management of those victims who in the past had died in Australia from our venomous and toxic fauna. Morgan, Graydon, Weiner, Lane and Baxter at the Commonwealth Serum Laboratories emphasised the importance of cooperation between those expert at catching and milking the venomous creatures and those developing the antivenoms. Commercial antivenom manufacture began in Australia in 1930 with the tiger snake antivenom. This was followed by other antivenoms for the other important species (1955: taipan; 1956: brown snake; 1958: death adder; 1959: Papuan black snake; 1961: sea snake; 1962: polyvalent) including the first marine antivenoms in the world (1956: stonefish antivenom; 1970: box jellyfish) culminating, in 1980, with the release of the funnel web spider antivenom. More recent activity has focused on veterinary antivenoms and production of new generation human antivenoms for export (CroFab and ViperaTAB). This paper reviews some of the milestones of Australian toxinology, and antivenom development in particular, during the 20th century.

Digestive properties of the venom of the Australian Coastal Taipan, Oxyuranus scutellatus (Peters, 1867).

The digestive properties of Australian elapid snake venoms have not been studied to any great extent. To address this, the in vitro digestive properties of Oxyuranus scutellatus (Australian Coastal Taipan) venom were investigated in a simulation of the in vivo conditions using the parameters reported for the stomach of snakes and representative prey for this species. The amount of soluble protein released was measured over time using a bicinchoninic acid (BCA) assay. Dismembered mouse hindlegs were injected intramuscularly with 0.1 ml O. scutellatus venom (concentration 10 mg/ml) and maintained in a micro-anaerobic, acidic environment (pH approximately 1.2-1.7) at 25 degrees C. The bathing liquid was sampled every 24 h for 7 days, and assayed for soluble protein. Statistical analysis revealed that O. scutellatus venom increased the rate at which proteins were released when compared to a negative control suggesting the potential importance of envenomation in the digestion of whole prey.