Bitis Gabonica Research Articles

Snake species assemblages across habitat types in four departments of the Republic of Congo, with emphasis on medically-relevant venomous species

Snakebite is a neglected public health crisis in sub-Saharan Africa. There is a particular lack of data (on snakes and snakebite) from the central African region. This study was conducted in the departments of Likouala, Sangha, Cuvette-Ouest and Kouilou, in the Republic of Congo. The objective was to inventory snakes in the four localities with particular emphasis on medically relevant venomous snakes in order to improve knowledge of snakes in order to minimize the risks of snakebite envenomation to humans. Two methods (active and passive) were used to collect specimens from different habitats. Fifty-one (51)snake specimens including 14 medically relevant snake specimens representing 3 families, 3 subfamilies, 5 genera, and 6 species, in addition to 22 harmless species, were collected. We found a high number of medically important venomous species in Okoyo, Mokéko and Mvouti districts with 3 species each. The highest number of medically important venomous species was recorded in natural forests and human habitations, five and four species respectively. The species obtained (Atheris squamigera, Bitis arietans, Bitis gabonica, Dendroaspis jamesoni, Naja melanoleuca and Toxicodryas blandingii) are medically relevant toxic species according to the WHO classification. Further studies would be necessary to assess the epidemiology of bite risks snakes and educate the public to minimize accidental human-snake contact.

ANALYSIS OF HUNTERS' RETURN IN THREE MAJOR BUSHMEAT DEPOTS, IN SOUTH-WEST NIGERIA

Submissions of game harvested by hunters per expedition to bushmeat landing depots in Southwestern Nigeria were studied for one year. Three established bushmeat landing depots were purposively selected for the study. Olomore and Kila in Ogun State and Odo Ona in Oyo State. The three were so selected because of their distribution along almost the same line of geographical placement on a line with Kila falling in between the other two on a line. Hunters’ return of harvested game after overnight hunting to the three locations on weekly basis was identified and counted for a year. Twenty-one (21) species of Vertebrates in the class Mammalia, reptiles and birds were returned to the three bushmeat depots by hunters during the study. Location-wise, Olomore had the highest return (1,457) and the least was returned to Kila (987) both in Ogun State. Species-wise, Thryonomys swinderianus (Grasscutter) had the highest population of 2,383 animals with a mean value of 794.3 ± 180.58, followed by Cephalophus maxwelli (duiker) with a mean value of 184.0 ± 32.51. The least hunters’ returns were Bitis gabonica (Black cobra) and Perodicticus potto (Bosmans potto) with a mean value of 0.33 ± 0.58 and 0.67 ± 1.15 respectively.

Intrageneric cross-reactivity of monospecific rabbit antisera against venoms of the medically most important Bitis spp. and Echis spp. African snakes.

BackgroundSnakebite envenomation exerts a heavy toll in sub-Saharan Africa. The design and production of effective polyspecific antivenoms for this region demand a better understanding of the immunological characteristics of the different venoms from the most medically important snakes, to select the most appropriate venom combinations for generating antivenoms of wide neutralizing scope. Bitis spp. and Echis spp. represent the most important viperid snake genera in Africa.Methodology/Principal findingsEight rabbit-derived monospecific antisera were raised against the venoms of four species of Bitis spp. and four species of Echis spp. The effects of immunization in the rabbits were assessed, as well as the development of antibody titers, as judged by immunochemical assays and neutralization of lethal, hemorrhagic, and in vitro coagulant effects. At the end of immunizations, local and pulmonary hemorrhage, together with slight increments in the plasma activity of creatine kinase (CK), were observed owing to the action of hemorrhagic and myotoxic venom components. Immunologic analyses revealed a considerable extent of cross-reactivity of monospecific antisera against heterologous venoms within each genus, although some antisera provided a more extensive cross-reactivity than others. The venoms that generated antisera with the broadest coverage were those of Bitis gabonica and B. rhinoceros within Bitis spp. and Echis leucogaster within Echis spp.Conclusions/SignificanceThe methodology followed in this study provides a rational basis for the selection of the best combination of venoms for generating antivenoms of high cross-reactivity against viperid venoms in sub-Saharan Africa. Results suggest that the venoms of B. gabonica, B. rhinoceros, and E. leucogaster generate antisera with the broadest cross-reactivity within their genera. These experimental results in rabbits need to be translated to large animals used in antivenom production to assess whether these predictions are reproduced in horses or sheep.

Preclinical Immuno-recognition and Neutralization of Lethality Assessment of a New Polyvalent Antivenom, VINS Snake Venom Antiserum – African IHS®, against Envenomation of Ten African Viperid and Elapid Snakes

Snakebite envenomation is a major health concern in developing countries causing significant mortality and morbidity. With over 1.2 million cases annually caused by medically important snake species belonging to the two families Viperidae (Echis spp. and Bitis spp.) and Elapidae (Naja spp. and Dendroaspis spp.). Several antivenoms are being produced and distributed to western sub-Saharan Africa for treatment of envenomation with the absence of preclinical efficacy studies. The present study evaluated the preclinical efficacy of venoms from Echis leucogaster, Echis ocellatus, Bitis arietans, Bitis gabonica, Naja haje, Naja melanoleuca, Naja nigricollis, Dendroaspis jamesoni, Dendroaspis polylepis and Dendroaspis viridis against a polyvalent Snake Venom Antiserum - African IHS (lyophilised), manufactured by VINS Bioproducts Limited (Telangana, India). Our in vitro results showed that, the SVA- AIHS contains antibodies that are capable of recognizing and binding majority of protein components representative of all eight major protein families of venoms of the snake species tested by double immunodiffusion assay and confirmed by western blot. The venom antiserum exhibited high neutralization efficacy against all the viperid and elapid snake species venoms in in vivo studies and confirmed the manufacturer’s recommended neutralization capacity. This is clear evidence that the VINS polyvalent SVA-AIHS batch tested has strong neutralizing capacity and will be useful in treating envenoming by most African viperid and some elapid snake species.

A looming exotic reptile pet trade in India: patterns and knowledge gaps

Commercial trade of exotic reptiles through CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) in India is relatively recent (<2 decades). Social media platforms and web portals are known to be used for pet trade. Exotic pet trade is not legally regulated within India. Therefore, little is known on the scale at which this trade is carried out in India. We conducted a two-year study between 2018 and 2020 gathering information of exotic reptile pet trade online and summarized CITES documentation of the yearly import export records from 1976 to 2018 by CITES secretariat. This manuscript provides a baseline for the extent of the trade, invasive species and the species traded in mainland India. We found that there is an extensive trade of exotic reptiles in the country, comprising 84 species including the highly venomous species such as Bitis gabonica. According to CITES records of 1976–2018, 98.6% of the reptile imports into India have not been reported to the CITES management authorities in India. We also found some evidence of trade in protected native species through the exotic pet trade network. Furthermore, some highly threatened reptile species including many listed in Appendix I of CITES are traded in India.

Biomimetic Ultra‐Black Sponge Derived from Loofah and Co‐MOF for Long‐Term Solar‐Powered Vapor Generation and Desalination

Designing ultra‐black materials with strong and broadband light absorption and efficient photothermal conversion properties is of great importance in many fields, including camouflage, catalysis, thermal therapy, and solar energy conversion. The West African Gaboon viper (Bitis rhinoceros), a master of camouflage, features black spots on its dorsal scales. The crest‐ridge structure in its black scales has been proven to be a typical antireflection structure. Herein, an artificial biomimetic ultra‐black sponge (BUBS) that imitates the crest‐ridge structure in the black scales of B. rhinoceros is successfully fabricated through growth of vertically aligned carbon nanosheet arrays derived from cobalt‐based metal–organic framework (Co‐MOF) on a loofah sponge. The vertically aligned carbon nanosheet arrays result in enhanced broadband light absorption (up to 97.08% on average) and photothermal conversion (equilibrium temperature of 80.7 °C under 1 sun illumination) of BUBS. Benefiting from its efficient light absorption and photothermal conversion, the BUBS is incorporated into solar‐powered vapor generation and desalination devices. The BUBS shows a higher water evaporation rate and efficiency of 1.93 kg m−2 h−1 and 98.5%, respectively, compared with other state‐of‐the‐art devices under 1 sun illumination. Furthermore, the BUBS also shows continuous and high water evaporation rates and excellent salt‐rejection in various brines, ensuring its potential application in solar‐powered desalination.

Information transfer efficiency differs in wild chimpanzees and bonobos, but not social cognition.

Several theories have been generated to understand the socio-cognitive mechanisms underlying the unique cooperative abilities of humans. The ‘interdependence hypothesis' posits first, that the cognitive dimension of human cooperation evolved in contexts when several individuals needed to act together to achieve a common goal, like when hunting large prey. Second, the more interdependent individuals are, the more likely they are to provide services to conspecifics in other contexts. Alternatively, the ‘social tolerance hypothesis' proposes that higher social tolerance allows conspecifics to cooperate more efficiently and with a wider range of partners. We conducted the first field experimental evaluation of both hypotheses in our closest living relatives by contrasting chimpanzees to the less interdependent but more tolerant bonobos. We compared each species' performance during a cooperative task: informing conspecifics about a danger. We presented Gaboon viper models to 82 individuals from five wild communities. Chimpanzees arriving late at the snake were significantly more likely to have heard a call and less likely to startle, indicating that chimpanzees were better informed about the presence of the threat than bonobos. This stems from clear species differences in how individuals adjusted their calling decisions to the level of information already available. Chimpanzees were more likely to call and produced more alarm calls when they had not yet heard a call, whereas bonobos did so when they already heard a call. Our results confirm the link between interdependence and cooperation performance. These species differences were most likely driven by differences in motivation rather than in cognitive capacities because both species tended to consider audience knowledge in their decision to call. Our results inform theories on the evolution of human cooperation by linking inter-group competition pressure and in-group cooperative motivation and/or capability.

Effect of Bitis gabonica and Dendroaspis angusticeps snake venoms on apoptosis-related genes in human thymic epithelial cells.

Background: Certain environmental toxins permanently damage the thymic epithelium, accelerate immune senescence and trigger secondary immune pathologies. However, the exact underlying cellular mechanisms and pathways of permanent immune intoxication remain unknown. The aim of the present study was to demonstrate gene expressional changes of apoptosis-related cellular pathways in human thymic epithelial cells following exposure to snake venom from Bitis gabonica and Dendroaspis angusticeps. Methods: Snake venoms were characterized by analytical methods including reversed phase high-performance liquid chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, then applied on human thymic epithelial cells (1889c) for 24 h at 10 μg/mL (as used in previous TaqMan Array study). Gene expressional changes restricted to apoptosis were assayed by TaqMan Array (Human Apoptosis Plate).Results: The most prominent gene expressional changes were shown by CASP5 (≈ 2.5 million-fold, confirmed by dedicated quantitative polymerase chain reaction) and CARD9 (0.016-fold) for B. gabonica, and BIRC7 (6.46-fold) and CASP1 (0.30-fold) for D. angusticeps. Conclusion: The observed apoptotic environment suggests that pyroptosis may be the dominant pathway through which B. gabonica and D. angusticeps snake venoms trigger thymic epithelial apoptosis following envenomation.

An in vivo examination of the differences between rapid cardiovascular collapse and prolonged hypotension induced by snake venom

We investigated the cardiovascular effects of venoms from seven medically important species of snakes: Australian Eastern Brown snake (Pseudonaja textilis), Sri Lankan Russell’s viper (Daboia russelii), Javanese Russell’s viper (D. siamensis), Gaboon viper (Bitis gabonica), Uracoan rattlesnake (Crotalus vegrandis), Carpet viper (Echis ocellatus) and Puff adder (Bitis arietans), and identified two distinct patterns of effects: i.e. rapid cardiovascular collapse and prolonged hypotension. P. textilis (5 µg/kg, i.v.) and E. ocellatus (50 µg/kg, i.v.) venoms induced rapid (i.e. within 2 min) cardiovascular collapse in anaesthetised rats. P. textilis (20 mg/kg, i.m.) caused collapse within 10 min. D. russelii (100 µg/kg, i.v.) and D. siamensis (100 µg/kg, i.v.) venoms caused ‘prolonged hypotension’, characterised by a persistent decrease in blood pressure with recovery. D. russelii venom (50 mg/kg and 100 mg/kg, i.m.) also caused prolonged hypotension. A priming dose of P. textilis venom (2 µg/kg, i.v.) prevented collapse by E. ocellatus venom (50 µg/kg, i.v.), but had no significant effect on subsequent addition of D. russelii venom (1 mg/kg, i.v). Two priming doses (1 µg/kg, i.v.) of E. ocellatus venom prevented collapse by E. ocellatus venom (50 µg/kg, i.v.). B. gabonica, C. vegrandis and B. arietans (all at 200 µg/kg, i.v.) induced mild transient hypotension. Artificial respiration prevented D. russelii venom induced prolonged hypotension but not rapid cardiovascular collapse from E. ocellatus venom. D. russelii venom (0.001–1 μg/ml) caused concentration-dependent relaxation (EC50 = 82.2 ± 15.3 ng/ml, Rmax = 91 ± 1%) in pre-contracted mesenteric arteries. In contrast, E. ocellatus venom (1 µg/ml) only produced a maximum relaxant effect of 27 ± 14%, suggesting that rapid cardiovascular collapse is unlikely to be due to peripheral vasodilation. The prevention of rapid cardiovascular collapse, by ‘priming’ doses of venom, supports a role for depletable endogenous mediators in this phenomenon.

A remarkable example of suspected Batesian mimicry of Gaboon Vipers (Reptilia: Viperidae: Bitis gabonica) by Congolese Giant Toads (Amphibia: Bufonidae: Sclerophrys channingi)

ABSTRACTBatesian mimicry is a phenomenon in nature whereby a non-toxic animal emulates a noxious one, seeking to deter predators by deception. This type of mimicry occurs in many animals, with numerous documented examples of invertebrates, harmless squamates, and even birds that mimic venomous snakes. However, no observations of anurans mimicking venomous snakes have been reported. Based on comparative data from colour pattern, morphology, geographic distribution and behaviour, we propose that the Congolese Giant Toad (Sclerophrys channingi), endemic to Democratic Republic of Congo, is a Batesian mimic of the geographically widespread Gaboon Viper (Bitis gabonica). Although the colour pattern similarity between these taxa is not an exact match, aposematism and precise imitation are not required for Batesian mimicry to be effective, especially when the model (B. gabonica) is dangerously venomous and carefully avoided by other vertebrates. Given the morphological similarity between S. channingi and two other African toad species (S. brauni and S. superciliaris) that are sympatric with B. gabonica and its sister taxon (B. rhinoceros), similar examples of Batesian mimicry are likely.

Life history and age-dependent mortality processes in tropical reptiles

AbstractActuarial senescence appears to be a common process, and senescence patterns are highly variable across the tree of life. To date, studies on animal senescence have largely focused on model species, such as as fruit flies, humans and a few other endotherms. In contrast, our knowledge about ageing remains fragmentary in ectotherm vertebrates, such as reptiles. Here, we examined life history and age-dependent mortality patterns in three tropical tortoises (Kinixys erosa, Kinixys homeana and Kinixys nogueyi) and snakes (Bitis gabonica, Bitis nasicornis and Causus maculatus). Our study revealed that tortoises of the genus Kinixys had a higher survival and a lower recruitment than snakes of the genera Bitis and Causus, indicating a slower life history. Furthermore, we confirmed that survival decreased more slowly with age in tortoises than in snakes. In addition, we highlighted contrasting patterns of age-dependent mortality among the three genera. In Kinixys, the relationship between mortality rate and age was positive and linear, suggesting gradual senescence over tortoise lifetime. In contrast, the relationship between mortality rate and age was negative and sharp in Bitis and Causus, possibly owing to a ‘negative senescence’. Our study is one of the few to have examined and compared the demography and age-dependent mortality patterns of tropical reptiles. Among other things, our results suggest that although negative senescence has never been reported in endotherm vertebrates, it could be a common phenomenon in ectotherms.

The neutralization efficacy of expired polyvalent antivenoms: An alternative option

The expense of production and distribution of snakebite antivenom, as well as its relatively infrequent use, has caused antivenom to be increasingly difficult to obtain and ultimately producing an alarming global shortage. Unused, expired antivenom may represent a significant, untapped resource to ameliorate this crisis. This study examines the efficacy of expired antivenom over time using in vitro, whole blood clotting, and platelet function statistics. Representatives from three years for four different global brands of polyvalent antivenom were chosen and tested against their corresponding venoms as well as other venoms that could display cross-reactivity. These antivenoms include Wyeth Polyvalent (U.S.; exp. 1997, 2001, 2003), Antivipmyn® (Mexico; exp. 2005, 2013, 2017), Biotecfars Polyvalent (Venezuela; exp. 2010, 2014, 2016), and SAIMR (South Africa; exp. 1997, 2005, 2017). Venoms of species tested were Crotalus atrox against Wyeth; C. atrox and Crotalus vegrandis against Antivipmyn®; C. atrox, C. vegrandis and Bothrops colombiensis against Biotecfar; and Bitis gabonica and Echis carinatus against South African Institute for Medical Research (SAIMR). Parameters recorded were activated clotting time (ACT), clotting rate (CR), and platelet function (PF). Preliminary results are encouraging as the antivenoms maintained significant efficacy even 20 y after their expiration date. We anticipate these results will motivate further studies and provide hope in the cases of snakebite emergencies when preferable treatments are unavailable.

Taking a Stab at Quantifying the Energetics of Biological Puncture.

An organism's ability to control the timing and direction of energy flow both within its body and out to the surrounding environment is vital to maintaining proper function. When physically interacting with an external target, the mechanical energy applied by the organism can be transferred to the target as several types of output energy, such as target deformation, target fracture, or as a transfer of momentum. The particular function being performed will dictate which of these results is most adaptive to the organism. Chewing food favors fracture, whereas running favors the transfer of momentum from the appendages to the ground. Here, we explore the relationship between deformation, fracture, and momentum transfer in biological puncture systems. Puncture is a widespread behavior in biology requiring energy transfer into a target to allow fracture and subsequent insertion of the tool. Existing correlations between both tool shape and tool dynamics with puncture success do not account for what energy may be lost due to deformation and momentum transfer in biological systems. Using a combination of pendulum tests and particle tracking velocimetry (PTV), we explored the contributions of fracture, deformation and momentum to puncture events using a gaboon viper fang. Results on unrestrained targets illustrate that momentum transfer between tool and target, controlled by the relative masses of the two, can influence the extent of fracture achieved during high-speed puncture. PTV allowed us to quantify deformation throughout the target during puncture and tease apart how input energy is partitioned between deformation and fracture. The relationship between input energy, target deformation and target fracture is non-linear; increasing impact speed from 2.0 to 2.5 m/s created no further fracture, but did increase deformation while increasing speed to 3.0 m/s allowed an equivalent amount of fracture to be achieved for less overall deformation. These results point to a new framework for examining puncture systems, where the relative resistances to deformation, fracture and target movement dictate where energy flows during impact. Further developing these methods will allow researchers to quantify the energetics of puncture systems in a way that is comparable across a broad range of organisms and connect energy flow within an organism to how that energy is eventually transferred to the environment.

Protease Activity Profiling of Snake Venoms Using High-Throughput Peptide Screening.

Snake venom metalloproteinases (SVMPs) and snake venom serine proteinases (SVSPs) are among the most abundant enzymes in many snake venoms, particularly among viperids. These proteinases are responsible for some of the clinical manifestations classically seen in viperid envenomings, including hemorrhage, necrosis, and coagulopathies. The objective of this study was to investigate the enzymatic activities of these proteins using a high-throughput peptide library to screen for the proteinase targets of the venoms of five viperid (Echis carinatus, Bothrops asper, Daboia russelii, Bitis arietans, Bitis gabonica) and one elapid (Naja nigricollis) species of high medical importance. The proteinase activities of these venoms were each tested against 360 peptide substrates, yielding 2160 activity profiles. A nonlinear regression model that accurately described the observed enzymatic activities was fitted to the experimental data, allowing for the comparison of cleavage rates across species. In this study, previously unknown protein targets of snake venom proteinases were identified, potentially implicating novel human and animal proteins that may be involved in the pathophysiology of viper envenomings. The functional relevance of these targets was further evaluated and discussed. These new findings may contribute to our understanding of the clinical manifestations and underlying biochemical mechanisms of snakebite envenoming by viperid species.

Spondyloarthropathy in vertebrae of the aquatic Cretaceous snake Lunaophis aquaticus, and its first recognition in modern snakes.

Inflammatory arthritis is documented for the first time in snakes. Ossification of the intervertebral capsule and zygapophyseal joints resulting in segmental vertebral fusion was observed in the aquatic Cretaceous snake Lunaophis aquaticus. Such pathologic alterations are pathognomonic for the spondyloarthropathy form of inflammatory arthritis. A survey of 2144 snakes in recent collections, performed to identify Holocene prevalence, revealed only two occurrences in extant snakes. The findings in Bitis gabonica and Elaphe taeniura were indistinguishable from those noted in Lunaophis aquaticus and identical to those previously recognized in modern varanids. The pathology likely represents a form of reactive arthritis related to enteropathic infection. While the disease probably did not affect general locomotion, its vertebral column position may have compromised mating.

Don't pet your gaboon viper!

Don't pet your gaboon viper!

Snake venoms from Angola: Intra-specific variations and immunogenicity

Snakebite is a public health problem in many countries of world. These accidents are considered a Neglected Tropical Disease and are responsible for a high morbidity and mortality index in the South and Southeast Asia and Sub-Saharan Africa. Angolan snake venoms are poorly investigated and no specific antivenom against them is available in the country. Thus, the aim of this study was to evaluate biochemical and immunogenic properties of male and female venoms from Naja nigricollis, Bitis arietans and Bitis gabonica snakes. These animals were collected during an expedition covering 1350 km of Angola, including the Provinces of Cuanza Sul, Benguela, Huíla and Malanje. Results showed that Angolan snake venoms present distinctive immunogenic properties and large intra-specific variations, associated to the gender and the geographic origin of the animals. Thus, it is possible to suggest that for the preparation of a therapeutic antivenom, intra-species variability should be taken into account, in order to obtain an efficient serum to neutralize the toxic effects of the Angolan snake venoms.

Isolation and biochemical characterization of bradykinin-potentiating peptides from Bitis gabonica rhinoceros

BackgroundVenoms represent a still underexplored reservoir of bioactive components that might mitigate or cure diseases in conditions in which conventional therapy is ineffective. The bradykinin-potentiating peptides (BPPs) comprise a class of angiotensin-I converting enzyme (ACE) inhibitors. The BPPs usually consist of oligopeptides with 5 to 13 residues with a high number of proline residues and the tripeptide Ile-Pro-Pro (IPP-tripeptide) in the C-terminus region and have a conserved N-terminal pyroglutamate residue. As a whole, the action of the BPPs on prey and snakebite victims results in the decrease of the blood pressure. The aim of this work was to isolate and characterize novel BPPs from the venom of Bitis gabonica rhinoceros.MethodsThe crude venom of B. g. rhinoceros was fractionated by size exclusion chromatography and the peptide fraction (<7 kDa) was separated by reverse phase chromatography (RP-HPLC) and analyzed by ESI-IT-TOF-MS/MS. One new BPP was identified, synthetized and assayed for ACE inhibition and, in vivo, for edema potentiation.ResultsTypical BPP signatures were identified in three RP-HPLC fractions. CID fragmentation presented the usual y-ion of the terminal P-P fragment as a predominant signal at m/z 213.1. De novo peptide sequencing identified one Bothrops-like BPP and one new BPP sequence. The new BPP was synthesized and showed poor inhibition over ACE, but displayed significant bradykinin-induced edema potentiation.ConclusionsSo far, few BPPs are described in Viperinae, and based on the sequenced peptides, two non-canonical sequences were detected. The possible clinical role of this new peptides remains unclear.

Cuticular microstructures turn specular black into matt black in a stick insect

The stick insect Peruphasma schultei stands out from other insects by its deep matt black cuticle. We tested whether the appearance of P. schultei is due to microstructures of the cuticle, a phenomenon that has recently been described for the velvet black scales of the Gaboon viper. The shiny black stick insect Anisomorpha paromalus served as a control. We found that the P. schultei cuticle is characterised by two different types of microstructures, tall elevations with a maximum size of 18 μm and small structures with a height of 4 μm. Other than in the snake, P. schultei microstructures do not bear nanostructures. The microstructures scatter light independently of the viewing angle. This causes the matt appearance of the cuticle, whereas pigments are responsible for the black colouration, resulting in a maximum reflectance of 2.8% percent. The microstructures also cause the hydrophobic properties of the cuticle with contact angles near 130°. Resin replicas and bleaching of the cuticle strongly support these results. Moreover, the matt black cuticle has a higher heat absorption compared to the control. We discuss the selective benefit of the matt black appearance of P. schultei in the context of behaviour, ecology and phylogeny.

Decreased snake venom metalloproteinase effects via inhibition of enzyme and modification of fibrinogen.

Since the introduction of antivenom administration 120years ago to treat venomous snake bit, it has been the gold standard for saving life and limb. However, this therapeutic approach is not always effective and not without potential life-threatening side effects. We tested a new paradigm to abrogate the plasmatic anticoagulant effects of fibrinogenolytic snake venom metalloproteinases by modification of fibrinogen with iron and carbon monoxide and by inhibiting these Zn(2+) dependent metalloproteinases directly with carbon monoxide exposure. Assessment of the fibrinogenolytic effects of venoms collected from Puff adder, Gaboon viper and Indian cobra snakes on plasmatic coagulation kinetics was performed with thrombelastography. Pretreatment of plasma with iron and carbon monoxide exposure markedly attenuated the effects of all three venoms, and direct pretreatment of each venom with carbon monoxide also significantly decreased the ability to compromise coagulation. These results demonstrated that the introduction of a transition metal (e.g., modulation of the α-chain of fibrinogen with iron), modulation of transition metal in heme (e.g., carbon monoxide modulation of fibrinogen-bound heme iron), and direct inhibition of transition metal containing venom enzymes (e.g., CO binding to Zn(2+) or displacing Zn(2+) from the catalytic site) significantly decreased fibrinogenolytic activity. This biometal modulation strategy to attenuate the anticoagulant effects of snake venom metalloproteinases could potentially diminish hemostatic injury in envenomed patients until antivenom can be administered.