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André Ménez - One of the best experts on this subject based on the ideXlab platform.
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Production of recombinant Notechis 11′2L, an enzymatically active mutant of a phospholipase A2 from Notechis scutatus scutatus venom, as directly generated by cleavage of a fusion protein produced in Escherichia coli
European journal of biochemistry, 1993Co-Authors: Darren Hodgson, Sylvaine Gasparini, Pascal Drevet, Frédéric Ducancel, Françoise Bouet, Jean-claude Boulain, John B. Harris, André MénezAbstract:We have constructed an expression vector to produce, in Escherichia coli, a fusion protein containing successively two IgG binding domains from staphyloccocal protein A, a nine-amino-acid linker peptide terminating in a methionine residue and the phospholipase A2 Notechis 11'2L, an isoform of notexin of Notechis scutatus scutatus venom. Notechis 11'2L is a mutant of the naturally occurring Notechis 11'2 [Bouchier, C., Boyot, P., Tesson, F., Tremeau, O., Bouet, F., Hodgson, D., Boulain, J. C. & Menez, A. (1991) Eur. J. Biochem. 202, 493-500] in which Met8 has been replaced by Leu. The fusion protein was recovered in the periplasmic extract with a yield of 0.25 mg/l culture. It was hydrolyzed with cyanogen bromide, yielding a protein having the molecular mass, amino acid composition and N-terminal sequence of Notechis 11'2L. Notechis 11'2L and the wild Notechis 11'2 displayed identical circular dichroic spectra and shared similar enzymatic, myotoxic and antigenic properties, suggesting that the recombinant Notechis 11'2L was directly generated in a correctly folded form.
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production of recombinant Notechis 11 2l an enzymatically active mutant of a phospholipase a2 from Notechis scutatus scutatus venom as directly generated by cleavage of a fusion protein produced in escherichia coli
FEBS Journal, 1993Co-Authors: Darren Hodgson, Sylvaine Gasparini, Pascal Drevet, Frédéric Ducancel, Françoise Bouet, Jean-claude Boulain, John B. Harris, André MénezAbstract:We have constructed an expression vector to produce, in Escherichia coli, a fusion protein containing successively two IgG binding domains from staphyloccocal protein A, a nine-amino-acid linker peptide terminating in a methionine residue and the phospholipase A2 Notechis 11'2L, an isoform of notexin of Notechis scutatus scutatus venom. Notechis 11'2L is a mutant of the naturally occurring Notechis 11'2 [Bouchier, C., Boyot, P., Tesson, F., Tremeau, O., Bouet, F., Hodgson, D., Boulain, J. C. & Menez, A. (1991) Eur. J. Biochem. 202, 493-500] in which Met8 has been replaced by Leu. The fusion protein was recovered in the periplasmic extract with a yield of 0.25 mg/l culture. It was hydrolyzed with cyanogen bromide, yielding a protein having the molecular mass, amino acid composition and N-terminal sequence of Notechis 11'2L. Notechis 11'2L and the wild Notechis 11'2 displayed identical circular dichroic spectra and shared similar enzymatic, myotoxic and antigenic properties, suggesting that the recombinant Notechis 11'2L was directly generated in a correctly folded form.
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Notechis 11′2, a non-toxic phospholipase A2 from the venom of Notechis scutatus scutatus
European journal of biochemistry, 1991Co-Authors: Christiane Bouchier, Darren Hodgson, Françoise Bouet, Jean-claude Boulain, Philippe Boyot, Frédérique Tesson, Odile Trémeau, André MénezAbstract:Previously, we deduced the amino acid sequence of a novel phospholipase-A2-like protein (PLA2) from the nucleotide sequence of a cDNA isolated from a library prepared from the venom gland of the Australian elapid Notechis scutatus scutatus. The corresponding protein has now been identified, purified from the venom and named Notechis 11′2. Its complete amino acid sequence has been determined by automated Edman degradation of both the whole protein and peptides generated by Staphylococcus aureus protease digestion and chemical cleavage at a tryptophan residue. As predicted from its sequence which contains all the residues putatively required for PLA2 activity, Notechis 11′2 exhibits an esterase activity, preferentially against neutral phospholipids. However, despite its sequence homology with other highly toxic PLA2 present in the venom of Notechis scutatus scutatus, Notechis 11′2 has no lethal activity. This observation further supports the view that the lethal activity of PLA2 from Notechis scutatus scutatus is not due to the esterasic activity only.
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Notechis 11 2 a non toxic phospholipase a2 from the venom of Notechis scutatus scutatus
FEBS Journal, 1991Co-Authors: Christiane Bouchier, Darren Hodgson, Françoise Bouet, Jean-claude Boulain, Philippe Boyot, Frédérique Tesson, Odile Trémeau, André MénezAbstract:Previously, we deduced the amino acid sequence of a novel phospholipase-A2-like protein (PLA2) from the nucleotide sequence of a cDNA isolated from a library prepared from the venom gland of the Australian elapid Notechis scutatus scutatus. The corresponding protein has now been identified, purified from the venom and named Notechis 11′2. Its complete amino acid sequence has been determined by automated Edman degradation of both the whole protein and peptides generated by Staphylococcus aureus protease digestion and chemical cleavage at a tryptophan residue. As predicted from its sequence which contains all the residues putatively required for PLA2 activity, Notechis 11′2 exhibits an esterase activity, preferentially against neutral phospholipids. However, despite its sequence homology with other highly toxic PLA2 present in the venom of Notechis scutatus scutatus, Notechis 11′2 has no lethal activity. This observation further supports the view that the lethal activity of PLA2 from Notechis scutatus scutatus is not due to the esterasic activity only.
R. Manjunatha Kini - One of the best experts on this subject based on the ideXlab platform.
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Group D prothrombin activators from snake venom are structural homologues of mammalian blood coagulation factor Xa.
The Biochemical journal, 2003Co-Authors: Veena S Rao, Jeremiah S. Joseph, R. Manjunatha KiniAbstract:Procoagulant venoms of several Australian elapids contain proteinases that specifically activate prothrombin; among these, Group D activators are functionally similar to coagulation factor Xa (FXa). Structural information on this class of prothrombin activators will contribute significantly towards understanding the mechanism of FXa-mediated prothrombin activation. Here we present the purification of Group D prothrombin activators from three Australian snake venoms (Hoplocephalus stephensi, Notechis scutatus scutatus and Notechis ater niger) using a single-step method, and their N-terminal sequences. The N-terminal sequence of the heavy chain of hopsarin D (H. stephensi) revealed that a fully conserved Cys-7 was substituted with a Ser residue. We therefore determined the complete amino acid sequence of hopsarin D. Hopsarin D shows approximately 70% similarity with FXa and approximately 98% similarity with trocarin D, a Group D prothrombin activator from Tropidechis carinatus. It possesses the characteristic Gla domain, two epidermal growth factor-like domains and a serine proteinase domain. All residues important for catalysis are conserved, as are most regions involved in interactions with factor Va and prothrombin. However, there are some structural differences. Unlike FXa, hopsarin D is glycosylated in both its chains: in light-chain residue 52 and heavy-chain residue 45. The glycosylation on the heavy chain is a large carbohydrate moiety adjacent to the active-site pocket. Overall, hopsarin D is structurally and functionally similar to mammalian coagulation FXa.
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Effect of snake venom procoagulants on snake plasma: implications for the coagulation cascade of snakes.
Toxicon, 2002Co-Authors: Jeremiah S. Joseph, Maxey C. M. Chung, Peter Mirtschin, R. Manjunatha KiniAbstract:Several snake venoms contain proteinases that activate zymogens in the coagulation cascade and thus exhibit their procoagulant effects. While most procoagulant proteinases from snake venoms are dissimilar to coagulation factors, Group D (trocarin, notecarin) and C (pseutarin) prothrombin activators are structural and functional homologues of factor Xa and the prothrombinase complex, respectively. We examined the effect of these and other procoagulants from snake venoms as well as mammalian and snake thromboplastins on the coagulation of plasmas of Notechis scutatus, Pseudonaja textilis (both procoagulant venoms), Python reticulatus (non-venomous) and Crotalus atrox (non-procoagulant venom) snakes. The results indicate that the intrinsic pathway seems to be weak or absent only in venomous snakes, while the extrinsic pathway is fully functional in all snakes. Python and Crotalus plasmas have extrinsic pathways similar to that in mammals. In contrast, although Notechis and Pseudonaja plasmas were clotted by a Group C activator, they failed to clot upon the addition of factor Xa and Group D activators. The mechanism of this resistance is still elusive.
Simon G A Brown - One of the best experts on this subject based on the ideXlab platform.
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tiger snake Notechis spp envenoming australian snakebite project asp 13
The Medical Journal of Australia, 2012Co-Authors: Geoffrey K. Isbister, Nicholas A Buckley, Simon G A BrownAbstract:OBJECTIVES: To describe the clinical syndrome associated with definite tiger snake (Notechis spp) envenoming and to examine the ability of tiger snake antivenom (TSAV) to bind free venom in vivo. DESIGN, SETTING AND PARTICIPANTS: We conducted a prospective cohort study within the Australian Snakebite Project, reviewing all definite tiger snake envenoming cases between October 2004 and June 2011. Definite cases were identified by venom-specific enzyme immunoassay or expert snake identification. MAIN OUTCOME MEASURES: Clinical effects of tiger snake envenoming; peak venom concentrations; number of vials of antivenom administered. RESULTS: Fifty-six definite tiger snake envenomings were identified. Clinical effects included venom-induced consumption coagulopathy (VICC) (n = 53), systemic symptoms (n = 45), myotoxicity (n = 11) and neurotoxicity (n = 17). Thrombotic microangiopathy occurred in three patients, all of whom developed acute renal failure. There were no deaths. A bite-site snake venom detection kit test was done in 44 patients, but was positive for tiger snake in only 33 cases. Fifty-three patients received TSAV and eight of these patients had immediate hypersensitivity reactions, severe enough in one case to satisfy diagnostic criteria for severe anaphylaxis. The median peak venom concentration in 50 patients with pretreatment blood samples available was 3.2 ng/mL (interquartile range [IQR], 1-12 ng/mL; range 0.17-152 ng/mL). In 49 patients with post-treatment blood samples available, no venom was detected in serum after the first antivenom dose. Ten patients were given 1 vial of TSAV; the median dose was 2 vials (range, 1-4 vials). Pretreatment serum venom concentrations did not vary significantly between patients given 1 vial of TSAV and those given 2 or more vials. CONCLUSION: Tiger snake envenoming causes VICC, systemic symptoms, neurotoxicity and myotoxicity. One vial of TSAV, the dose originally recommended when the antivenom was first made available, appears to be sufficient to bind all circulating venom. Language: en
Richard Shine - One of the best experts on this subject based on the ideXlab platform.
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Genetic Assimilation and the Postcolonization Erosion of Phenotypic Plasticity in Island Tiger Snakes
Current biology : CB, 2009Co-Authors: Fabien Aubret, Richard ShineAbstract:School of Biological Sciences A08, University of Sydney,Sydney NSW 2006, AustraliaSummaryIn 1942, C.H. Waddington [1] suggested that colonizing pop-ulations could initially succeed by flexibly altering theircharacteristics (phenotypic plasticity; [2–4]) in fitness-inducing traits, but selective forces would rapidly eliminatethat plasticity to result in a canalized trait [1, 5, 6]. Wadding-tontermedthisprocess‘‘geneticassimilation’’[1,7].Despitethe potential importance of genetic assimilation to evolu-tionary changes in founder populations [8–10], empiricalevidence on this topic is rare, possibly because it happensonshorttimescalesandisthereforedifficulttodetectexceptunderunusualcircumstances[11,12].Weexploitedamosaicofsnakepopulationsisolated(orintroduced)onislandsfromless than 30 years ago to more than 9000 years ago andexposed to selection for increased head size (i.e., ability toingest large prey [13–16]). Here we show that a larger headsize is achieved by plasticity in ‘‘young’’ populations andby genetic canalization in ‘‘older’’ populations. Island tigersnakes (Notechis scutatus) thus show clear empiricalevidence of genetic assimilation, with the elaboration of anadaptivetraitshiftingfromphenotypicallyplasticexpressionthrough to canalization within a few thousand years.ResultsPopulation Differences in Body and Head Sizes at BirthComparisons of neonates among seven populations of tigersnakes (Notechis scutatus) revealed significant differences inbody dimensions at birth (body mass; nested analysis ofvariance [ANOVA] with litter nested into population, andbody mass as dependent variable: population effect F
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Swimming and pregnancy in Tiger snakes, Notechis scutatus
Amphibia-Reptilia, 2005Co-Authors: Fabien Aubret, Richard Shine, Xavier Bonnet, Stéphanie MaumelatAbstract:Reduced locomotor ability may increase susceptibility to predation and hence may represent a proximate mechanism by which “costs” of reproduction are expressed (Shine, 1980). In squamate reptiles, many examples of such effects have been documented, where non-gravid females and/or males showed higher survival rates than gravid females (Shine, 1980; Andren, 1982, 1985; Madsen, 1987). For instance, pregnancy may entail a reduction in locomotor performances in lizards and snakes (Shine, 1980; Shine, 2003; Bauwens and Thoen, 1981; Garland and Else, 1987; Seigel et al., 1987), including decreased burst speed by 12 to 30%, and endurance by 52 to 55%. Because fleeing from predators or foraging ability depends on speed and/or stamina, reduced locomotor performance resulting from carrying offspring may result in increased risk of predation and/or decreased energy intake compared to non-gravid females.
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How can blind tiger snakes (Notechis scutatus) forage successfully
Australian Journal of Zoology, 2005Co-Authors: Fabien Aubret, Xavier Bonnet, David Pearson, Richard ShineAbstract:On a small island off south-western Australia, tiger snakes (Notechis scutatus, Elapidae) continue to survive, feed, grow and reproduce successfully after being blinded by seagulls defending their chicks. We propose two alternative hypotheses to explain this surprising result: either vision is of trivial importance in tiger snake foraging, or the blinded snakes survive on a diet of abundant immobile prey that cannot escape their approach. Laboratory studies in which we blindfolded snakes falsified the first hypothesis: snakes that were unable to see had great difficulty in capturing mobile prey. Field data support the second hypothesis: blind snakes feed almost entirely on seagull chicks, whereas normal-sighted animals also took fast-moving prey (lizards and mice). Thus, the ability of tiger snakes on Carnac Island to survive without vision is attributable to the availability of abundant helpless prey (seagull chicks) in this insular ecosystem.
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Battles for mates and food: Intraspecific combat in island tigersnakes (Notechis ater) from southern Australia
Amphibia-Reptilia, 1996Co-Authors: Richard Shine, M. FirmageAbstract:Male-male combat occurs in mainland populations of tigersnakes (Notechis scutatus), but authorities have disagreed as to whether or not this behaviour also occurs in island tigersnakes (Notechis ater). In this paper, we confirm that intraspecific combat frequently occurs between island tigersnakes maintained in captivity. Two different kinds of combat bouts were observed. We interpret the first type (ritualised "wrestling" matches between large adult males) as a reflection of sexual competition. This behaviour was seen in snakes from each of the island populations investigated, including Tasmania. Agonistic behaviour was exhibited by females and juveniles as well as by adult males: however, this second type of combat was always initiated by the introduction of food items to the enclosure, and incorporated vigorous biting as well as (or instead of) wrestling. Further observations, in the field as well as in captivity, are needed before we can interpret the functional significance of this behaviour. The food-induced combat may be an artifact of high densities of captive snakes, or alternatively may be exhibited in the wild also. We speculate that the high abundance of tigersnakes on some islands, and the highly clumped nature of prey resources (e.g. muttonbird chicks) in both space and time, may have favoured direct interference competition for prey items between island tigersnakes. If so, some elements of the social system of island tigersnakes may resemble the condition seen in many lizard species, rather than in other snakes.
Fabien Aubret - One of the best experts on this subject based on the ideXlab platform.
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Effect of sudden loss of vision on foraging behavior in captive born Tiger Snakes, Notechis scutatus (Serpentes: Elapidae)
Phyllomedusa: Journal of Herpetology, 2016Co-Authors: Fabien AubretAbstract:In animals, survival often is compromised when vision is partially or totally lost as a result of injury or disease (Martin 1981, Brown et al. 1984, Gauthier 1991). However, under particular circumstances, sudden loss of vision may have little impact on viability, as has been shown in wild populations of the Australian Tiger Snake, Notechis scutatus (Peters 1861, Bonnet et al. 1999, Aubret et al. 2005, Aubret and Thomas 2009). Carnac Island in Western Australia hosts a large population of Tiger Snakes in which many adult individuals have sustained severe ...
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Genetic Assimilation and the Postcolonization Erosion of Phenotypic Plasticity in Island Tiger Snakes
Current biology : CB, 2009Co-Authors: Fabien Aubret, Richard ShineAbstract:School of Biological Sciences A08, University of Sydney,Sydney NSW 2006, AustraliaSummaryIn 1942, C.H. Waddington [1] suggested that colonizing pop-ulations could initially succeed by flexibly altering theircharacteristics (phenotypic plasticity; [2–4]) in fitness-inducing traits, but selective forces would rapidly eliminatethat plasticity to result in a canalized trait [1, 5, 6]. Wadding-tontermedthisprocess‘‘geneticassimilation’’[1,7].Despitethe potential importance of genetic assimilation to evolu-tionary changes in founder populations [8–10], empiricalevidence on this topic is rare, possibly because it happensonshorttimescalesandisthereforedifficulttodetectexceptunderunusualcircumstances[11,12].Weexploitedamosaicofsnakepopulationsisolated(orintroduced)onislandsfromless than 30 years ago to more than 9000 years ago andexposed to selection for increased head size (i.e., ability toingest large prey [13–16]). Here we show that a larger headsize is achieved by plasticity in ‘‘young’’ populations andby genetic canalization in ‘‘older’’ populations. Island tigersnakes (Notechis scutatus) thus show clear empiricalevidence of genetic assimilation, with the elaboration of anadaptivetraitshiftingfromphenotypicallyplasticexpressionthrough to canalization within a few thousand years.ResultsPopulation Differences in Body and Head Sizes at BirthComparisons of neonates among seven populations of tigersnakes (Notechis scutatus) revealed significant differences inbody dimensions at birth (body mass; nested analysis ofvariance [ANOVA] with litter nested into population, andbody mass as dependent variable: population effect F
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food versus risk foraging decision in young tiger snakes Notechis scutatus
Amphibia-reptilia, 2007Co-Authors: Don Bradshaw, Xavier Bonnet, Fabien AubretAbstract:Foraging behaviour is influenced by an animal's level of hunger, and may reflect a trade-off between optimizing food acquisition and avoiding predation. Young tiger snakes were raised either on a high or low food diet and exposed to a predation threat while foraging. Under these circumstances, lower condition snakes (low food diet) were prone to take additional feeding/foraging risks: food was accepted at a much higher rate compared with the higher condition animals (high food diet) that were less inclined to risk feeding under a predation threat. This study provides the first direct example of predation risk-associated foraging decisions in snakes.
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Swimming and pregnancy in Tiger snakes, Notechis scutatus
Amphibia-Reptilia, 2005Co-Authors: Fabien Aubret, Richard Shine, Xavier Bonnet, Stéphanie MaumelatAbstract:Reduced locomotor ability may increase susceptibility to predation and hence may represent a proximate mechanism by which “costs” of reproduction are expressed (Shine, 1980). In squamate reptiles, many examples of such effects have been documented, where non-gravid females and/or males showed higher survival rates than gravid females (Shine, 1980; Andren, 1982, 1985; Madsen, 1987). For instance, pregnancy may entail a reduction in locomotor performances in lizards and snakes (Shine, 1980; Shine, 2003; Bauwens and Thoen, 1981; Garland and Else, 1987; Seigel et al., 1987), including decreased burst speed by 12 to 30%, and endurance by 52 to 55%. Because fleeing from predators or foraging ability depends on speed and/or stamina, reduced locomotor performance resulting from carrying offspring may result in increased risk of predation and/or decreased energy intake compared to non-gravid females.
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How can blind tiger snakes (Notechis scutatus) forage successfully
Australian Journal of Zoology, 2005Co-Authors: Fabien Aubret, Xavier Bonnet, David Pearson, Richard ShineAbstract:On a small island off south-western Australia, tiger snakes (Notechis scutatus, Elapidae) continue to survive, feed, grow and reproduce successfully after being blinded by seagulls defending their chicks. We propose two alternative hypotheses to explain this surprising result: either vision is of trivial importance in tiger snake foraging, or the blinded snakes survive on a diet of abundant immobile prey that cannot escape their approach. Laboratory studies in which we blindfolded snakes falsified the first hypothesis: snakes that were unable to see had great difficulty in capturing mobile prey. Field data support the second hypothesis: blind snakes feed almost entirely on seagull chicks, whereas normal-sighted animals also took fast-moving prey (lizards and mice). Thus, the ability of tiger snakes on Carnac Island to survive without vision is attributable to the availability of abundant helpless prey (seagull chicks) in this insular ecosystem.
