Y. Sawai, M. Honma, Y. Kawamura, A. Saki, M. Hatsuse
The yamakagashi (Rhabdophis tigrinus), a colubrid snake, is common in Japan. However, largely because the snake is rear-fanged, severe bites occur rarely, and only 29 cases of yamakagashi bites have been reported since 1917. The epidemiological analysis of the severe bites indicates that most of the bites occurred in warmer months, from April to October. Most of the bites occurred in males trying to catch snakes while in residence, in the field and on the road during daylight hours. Systemic symptoms including continuous bleeding from the bite wound, gums, hematuria, ecchymosis of the body, and coagulation abnormalities of the blood are induced by a hemorrhagic factor and prothrombin activator found in the venom; fatalities occur rarely. An antivenom was produced by immunizing rabbits and goats with yamakagashi venom. The γ-globulin separated from the blood of immunized animals (antivenom) was effective at preventing hemorrhage and coagulation abnormalities of the blood of envenomated patients.
{"title":"Rhabdophis tigrinus IN JAPAN: PATHOGENESIS OF ENVENOMATION AND PRODUCTION OF ANTIVENOM","authors":"Y. Sawai, M. Honma, Y. Kawamura, A. Saki, M. Hatsuse","doi":"10.1081/TXR-120004746","DOIUrl":"https://doi.org/10.1081/TXR-120004746","url":null,"abstract":"The yamakagashi (Rhabdophis tigrinus), a colubrid snake, is common in Japan. However, largely because the snake is rear-fanged, severe bites occur rarely, and only 29 cases of yamakagashi bites have been reported since 1917. The epidemiological analysis of the severe bites indicates that most of the bites occurred in warmer months, from April to October. Most of the bites occurred in males trying to catch snakes while in residence, in the field and on the road during daylight hours. Systemic symptoms including continuous bleeding from the bite wound, gums, hematuria, ecchymosis of the body, and coagulation abnormalities of the blood are induced by a hemorrhagic factor and prothrombin activator found in the venom; fatalities occur rarely. An antivenom was produced by immunizing rabbits and goats with yamakagashi venom. The γ-globulin separated from the blood of immunized animals (antivenom) was effective at preventing hemorrhage and coagulation abnormalities of the blood of envenomated patients.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75189632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the largest groups of snakes is the family Colubridae. This is a paraphyletic assemblage that includes a few venomous species, but most pose no special health risk to humans. Thirty to forty percent of colubrids possess a Duvernoy's gland, a specialized oral gland located in the temporal region. Although it is a homologue to the venom glands of viperid and elapid snakes, the Duvernoy's gland is anatomically and functionally distinct. Generally it lacks a large internal reservoir of secretion, emptying is under low-pressure flow, and the secretion is not delivered via hollow fangs. In contrast, true venom glands hold a large store of ready venom, expel the venom under direct action of striated muscles, and inject it as a high-pressure pulse via hollow fangs. Both the Duvernoy's gland and the venom gland are part of a snake's trophic system, involved primarily in predatory behavior. True venoms are composed of potent toxins whose main biological role is to bring about rapid prey death. Although the secretion from the Duvernoy's gland may include toxins, surprisingly only a few colubrids deploy it similarly to kill prey quickly. In fact, the biological role(s) of Duvernoy's secretion remain today largely unknown. Therefore, it is misleading, in a functional and evolutionary context, automatically to call Duvernoy's secretion a venom (biological role) when only its pharmacology (property) is known. Although Duvernoy's secretion has some components in common with true venoms, some may be fundamentally different in chemical composition, likely because it is involved in different biological roles than a true venom. This means it likely includes novel chemical components with a promise of interest to human medicine.
{"title":"COLUBRID SNAKES AND DUVERNOY'S “VENOM” GLANDS","authors":"K. Kardong","doi":"10.1081/TXR-120004739","DOIUrl":"https://doi.org/10.1081/TXR-120004739","url":null,"abstract":"One of the largest groups of snakes is the family Colubridae. This is a paraphyletic assemblage that includes a few venomous species, but most pose no special health risk to humans. Thirty to forty percent of colubrids possess a Duvernoy's gland, a specialized oral gland located in the temporal region. Although it is a homologue to the venom glands of viperid and elapid snakes, the Duvernoy's gland is anatomically and functionally distinct. Generally it lacks a large internal reservoir of secretion, emptying is under low-pressure flow, and the secretion is not delivered via hollow fangs. In contrast, true venom glands hold a large store of ready venom, expel the venom under direct action of striated muscles, and inject it as a high-pressure pulse via hollow fangs. Both the Duvernoy's gland and the venom gland are part of a snake's trophic system, involved primarily in predatory behavior. True venoms are composed of potent toxins whose main biological role is to bring about rapid prey death. Although the secretion from the Duvernoy's gland may include toxins, surprisingly only a few colubrids deploy it similarly to kill prey quickly. In fact, the biological role(s) of Duvernoy's secretion remain today largely unknown. Therefore, it is misleading, in a functional and evolutionary context, automatically to call Duvernoy's secretion a venom (biological role) when only its pharmacology (property) is known. Although Duvernoy's secretion has some components in common with true venoms, some may be fundamentally different in chemical composition, likely because it is involved in different biological roles than a true venom. This means it likely includes novel chemical components with a promise of interest to human medicine.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80721544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Colubroids or advanced snakes form a monophyletic group comprising four families: Atractaspididae (11 genera, 70 species), “Colubridae” (300 genera, 1850 species), Elapidae (65 genera, 270 species) and Viperidae (33 genera, 240 species). A preliminary classification of colubroids based both on morphological and molecular data is presented and all extant genera of “Colubridae” are listed accordingly. The front-fanged venom system (displayed by some Atractaspididae, all Elapidae and all Viperidae) evolved several times independently and appeared early within colubroids. The rear-fanged venom system (displayed by some Atractaspididae and many “Colubridae”) has been studied less than the front-fanged system, although it is clear that opisthoglyph “Colubridae” constitute a polyphyletic group. The other components of the venom apparatus, the glands and the secretions, also show great variability, rendering the reconstruction of the evolutionary history of the venom apparatus difficult. Nevertheless, the presence of serous secretory cells in the supralabial region and of a differentiated maxillary dentition within the most basal extant lineages of advanced snakes strongly suggest that the venom apparatus is a synapomorphy of the Colubroidea and that its absence in a few “Colubridae” results from secondary losses.
{"title":"COLUBROID SYSTEMATICS: EVIDENCE FOR AN EARLY APPEARANCE OF THE VENOM APPARATUS FOLLOWED BY EXTENSIVE EVOLUTIONARY TINKERING","authors":"N. Vidal","doi":"10.1081/TXR-120004740","DOIUrl":"https://doi.org/10.1081/TXR-120004740","url":null,"abstract":"Colubroids or advanced snakes form a monophyletic group comprising four families: Atractaspididae (11 genera, 70 species), “Colubridae” (300 genera, 1850 species), Elapidae (65 genera, 270 species) and Viperidae (33 genera, 240 species). A preliminary classification of colubroids based both on morphological and molecular data is presented and all extant genera of “Colubridae” are listed accordingly. The front-fanged venom system (displayed by some Atractaspididae, all Elapidae and all Viperidae) evolved several times independently and appeared early within colubroids. The rear-fanged venom system (displayed by some Atractaspididae and many “Colubridae”) has been studied less than the front-fanged system, although it is clear that opisthoglyph “Colubridae” constitute a polyphyletic group. The other components of the venom apparatus, the glands and the secretions, also show great variability, rendering the reconstruction of the evolutionary history of the venom apparatus difficult. Nevertheless, the presence of serous secretory cells in the supralabial region and of a differentiated maxillary dentition within the most basal extant lineages of advanced snakes strongly suggest that the venom apparatus is a synapomorphy of the Colubroidea and that its absence in a few “Colubridae” results from secondary losses.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78401276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Insect pests decimate a significant proportion of the world's food supply and transmit a number of deadly human diseases. These arthropods are generally controlled by spraying broad-spectrum chemical insecticides. However, the emergence of insecticide-resistant insect populations, as well as increasing disquiet about the environmental and human health risks associated with certain agrochemicals, has stimulated the search for new arthropod-control strategies. Since the primary role of spider venoms is to kill or immobilize arthropod prey, it is not surprising that spider venoms have proved to be rich sources of insecticidal compounds. In this review we examine the function and three-dimensional structure of four families of novel insecticidal neurotoxins that have been isolated from the venom of Australian funnel-web spiders. Although all of these toxins are members of the inhibitor cystine-knot family, they have proved to be structural chameleons, with the three-dimensional fold often providing few clues about toxin function. However, significant progress is being made in identifying the targets and mapping the bioactive surfaces of these peptides. In addition to being useful lead compounds for insecticide design, these neurotoxins should provide valuable tools for the pharmacological and structural characterization of insecticide targets.
{"title":"STRUCTURE AND FUNCTION OF INSECTICIDAL NEUROTOXINS FROM AUSTRALIAN FUNNEL-WEB SPIDERS","authors":"G. King, H. Tedford, F. Maggio","doi":"10.1081/TXR-120014409","DOIUrl":"https://doi.org/10.1081/TXR-120014409","url":null,"abstract":"Insect pests decimate a significant proportion of the world's food supply and transmit a number of deadly human diseases. These arthropods are generally controlled by spraying broad-spectrum chemical insecticides. However, the emergence of insecticide-resistant insect populations, as well as increasing disquiet about the environmental and human health risks associated with certain agrochemicals, has stimulated the search for new arthropod-control strategies. Since the primary role of spider venoms is to kill or immobilize arthropod prey, it is not surprising that spider venoms have proved to be rich sources of insecticidal compounds. In this review we examine the function and three-dimensional structure of four families of novel insecticidal neurotoxins that have been isolated from the venom of Australian funnel-web spiders. Although all of these toxins are members of the inhibitor cystine-knot family, they have proved to be structural chameleons, with the three-dimensional fold often providing few clues about toxin function. However, significant progress is being made in identifying the targets and mapping the bioactive surfaces of these peptides. In addition to being useful lead compounds for insecticide design, these neurotoxins should provide valuable tools for the pharmacological and structural characterization of insecticide targets.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85838580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many species of colubrid snakes from Africa, Europe and the Middle East produce toxic oral secretions. However, only a small number has caused envenomation in humans, and very few are of medical concern. Envenomations are rare and almost exclusively result from handling these animals. Apart from the very small group of people who capture and keep venomous colubrids, the health risks from these snakes to the general population are negligible. Envenomations by the majority of venomous colubrids in Africa, Europe and the Middle East will cause local symptoms of pain and edema of variable extent. Systemic envenomation is rare. Severe consumption coagulopathy and hemorrhagic diathesis have followed bites by the African tree snakes Dispholidus typus and Thelothornis capensis, which have a highly developed venom apparatus and extremely toxic venoms, and are capable of inflicting fatal human envenomation with a quick bite. A similar clinical picture was observed in cases of severe envenomation by the Asian colubrid Rhabdophis subminiatus, which has been imported to Europe by the pet trade. The treatment of colubrid envenomations in Africa, Europe and the Middle East is supportive and symptomatic. Careful monitoring of the patient is imperative, and asymptomatic patients should be hospitalized for at least 48 hr when bites were caused by Dispholidus, Thelotornis or Rhabdophis. Intensive care, replacement of blood and infusion of fibrinogen may be required in cases of hemorrhagic diathesis. Antivenoms raised against the venoms of viperid or elapid snakes are ineffective.
{"title":"ENVENOMATIONS BY COLUBRID SNAKES IN AFRICA, EUROPE, AND THE MIDDLE EAST","authors":"U. Kuch, D. Mebs","doi":"10.1081/TXR-120004745","DOIUrl":"https://doi.org/10.1081/TXR-120004745","url":null,"abstract":"Many species of colubrid snakes from Africa, Europe and the Middle East produce toxic oral secretions. However, only a small number has caused envenomation in humans, and very few are of medical concern. Envenomations are rare and almost exclusively result from handling these animals. Apart from the very small group of people who capture and keep venomous colubrids, the health risks from these snakes to the general population are negligible. Envenomations by the majority of venomous colubrids in Africa, Europe and the Middle East will cause local symptoms of pain and edema of variable extent. Systemic envenomation is rare. Severe consumption coagulopathy and hemorrhagic diathesis have followed bites by the African tree snakes Dispholidus typus and Thelothornis capensis, which have a highly developed venom apparatus and extremely toxic venoms, and are capable of inflicting fatal human envenomation with a quick bite. A similar clinical picture was observed in cases of severe envenomation by the Asian colubrid Rhabdophis subminiatus, which has been imported to Europe by the pet trade. The treatment of colubrid envenomations in Africa, Europe and the Middle East is supportive and symptomatic. Careful monitoring of the patient is imperative, and asymptomatic patients should be hospitalized for at least 48 hr when bites were caused by Dispholidus, Thelotornis or Rhabdophis. Intensive care, replacement of blood and infusion of fibrinogen may be required in cases of hemorrhagic diathesis. Antivenoms raised against the venoms of viperid or elapid snakes are ineffective.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72566402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The three-fingered α-neurotoxins isolated from the venoms of Elapidae family snakes have long been used as tools for the isolation and characterization of the nicotinic acetylcholine receptor (nAChR). These small proteins cause paralysis and death by binding to the nAChR at the neuromuscular junction and competitively antagonizing the action of acetylcholine. Snakes of the Viperidae family were not previously known to make toxins that target nAChR. A decade ago, four peptides of 22–24 amino acids were characterized from the venom of Wagler's Pit Viper, Tropidolaemus wagleri. These peptides are unique among the lethal components of Viperid venoms in that their lethal effects, like the three-fingered toxins, are mediated by competitive antagonism of muscle nAChR. One of these peptides, called Waglerin-1, also possesses a distinctive selectivity for the α–ε interface binding site of the mouse nAChR, binding with over 2000-fold higher affinity to the α–ε site compared to the α–δ or α–γ binding sites. Furthermore, it binds the α–ε interface site of cloned mouse nAChR with 100-fold higher affinity than both the rat or the human cloned receptors. The amino acid residues of the receptor mediating both the binding site and species selectivity have been determined. Additional work on the structure of the peptide itself has begun to elucidate the residues of the peptide most responsible for its high affinity and selectivity. The peptides produced by this unique snake provide researchers with a new structural template for studying nAChR and other receptors. Additional research into the low molecular weight venom components of T. wagleri and its cousins in the Viperidae family should yield new structural information on receptors and toxins.
{"title":"STRUCTURE AND FUNCTION OF THE WAGLERINS, PEPTIDE TOXINS FROM THE VENOM OF WAGLER'S PIT VIPER, TROPIDOLAEMUS WAGLERI","authors":"B. Molles, P. Taylor","doi":"10.1081/TXR-120014406","DOIUrl":"https://doi.org/10.1081/TXR-120014406","url":null,"abstract":"The three-fingered α-neurotoxins isolated from the venoms of Elapidae family snakes have long been used as tools for the isolation and characterization of the nicotinic acetylcholine receptor (nAChR). These small proteins cause paralysis and death by binding to the nAChR at the neuromuscular junction and competitively antagonizing the action of acetylcholine. Snakes of the Viperidae family were not previously known to make toxins that target nAChR. A decade ago, four peptides of 22–24 amino acids were characterized from the venom of Wagler's Pit Viper, Tropidolaemus wagleri. These peptides are unique among the lethal components of Viperid venoms in that their lethal effects, like the three-fingered toxins, are mediated by competitive antagonism of muscle nAChR. One of these peptides, called Waglerin-1, also possesses a distinctive selectivity for the α–ε interface binding site of the mouse nAChR, binding with over 2000-fold higher affinity to the α–ε site compared to the α–δ or α–γ binding sites. Furthermore, it binds the α–ε interface site of cloned mouse nAChR with 100-fold higher affinity than both the rat or the human cloned receptors. The amino acid residues of the receptor mediating both the binding site and species selectivity have been determined. Additional work on the structure of the peptide itself has begun to elucidate the residues of the peptide most responsible for its high affinity and selectivity. The peptides produced by this unique snake provide researchers with a new structural template for studying nAChR and other receptors. Additional research into the low molecular weight venom components of T. wagleri and its cousins in the Viperidae family should yield new structural information on receptors and toxins.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72593381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Craik, N. Daly, Manuel Plan, A. Salim, L. Sando
Plant toxins are substances produced and secreted by plants to defend themselves against predators. In a broad sense, this includes all substances that have a toxic effect on targeted organisms, whether they are microbes, other plants, insects, or higher animals. Plant toxins have a diverse range of structures, from small organic molecules through to proteins. This review gives an overview of the various classes of plant toxins but focuses on an interesting class of protein-based plant toxins containing a cystine knot motif. This structural motif confers exceptional stability on proteins containing it and is associated with a wide range of biological activities. The biological activities and structural stability offer many potential applications in the pharmaceutical and agricultural fields. One particularly exciting prospect is in the use of protein-based plant toxins as molecular scaffolds for displaying pharmaceutically important bioactivities. Future applications of plant toxins are likely to involve genetic engineering techniques and “molecular pharming” approaches.
{"title":"STRUCTURE AND FUNCTION OF PLANT TOXINS (WITH EMPHASIS ON CYSTINE KNOT TOXINS)","authors":"D. Craik, N. Daly, Manuel Plan, A. Salim, L. Sando","doi":"10.1081/TXR-120014405","DOIUrl":"https://doi.org/10.1081/TXR-120014405","url":null,"abstract":"Plant toxins are substances produced and secreted by plants to defend themselves against predators. In a broad sense, this includes all substances that have a toxic effect on targeted organisms, whether they are microbes, other plants, insects, or higher animals. Plant toxins have a diverse range of structures, from small organic molecules through to proteins. This review gives an overview of the various classes of plant toxins but focuses on an interesting class of protein-based plant toxins containing a cystine knot motif. This structural motif confers exceptional stability on proteins containing it and is associated with a wide range of biological activities. The biological activities and structural stability offer many potential applications in the pharmaceutical and agricultural fields. One particularly exciting prospect is in the use of protein-based plant toxins as molecular scaffolds for displaying pharmaceutically important bioactivities. Future applications of plant toxins are likely to involve genetic engineering techniques and “molecular pharming” approaches.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87161733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Most snakebites in South America are caused by pitvipers (Bothrops, Crotalus and Lachesis spp.) and coral snakes (Micrurus spp.), with less serious accidents caused by colubrids. Rear-fanged species are responsible for most colubrid envenomations, the principal genera involved being Clelia, Helicops, Liophis, Philodryas, Tachymenis, and Thamnodynastes. The hands, feet and upper and lower limbs are bitten most frequently. Most envenomations are mild, involving mainly local pain, edema and ecchymosis. Systemic envenomation (altered whole blood clotting time, systemic bleeding, shock, and renal failure) is rare and only one fatality suspected to have been caused by a colubrid (P. olfersii in Brazil) has been recorded. Treatment is symptomatic and supportive, and recovery is generally uneventful, with no sequelae. The similarity between the local effects of envenomations by colubrids and those produced by South American lanceheads (Bothrops spp.) has resulted in bothropic antivenom being administered in several cases, but there is little conclusive evidence that antivenom enhanced the patients' condition. Together, these findings indicate that envenomations by South American colubrids are considerably less serious than those reported for certain African and Asian colubrids (Boiga, Dispholidus, Rhabdophis and Thelotornis spp.). However, the limited number of species involved in human envenomations to date compared to the large number of South American colubrids currently recognized suggests the need for caution in generalizing about the potential seriousness of bites by species not yet implicated in such accidents.
{"title":"SOUTH AMERICAN COLUBRID ENVENOMATIONS","authors":"J. Prado-Franceschi, S. Hyslop","doi":"10.1081/TXR-120004744","DOIUrl":"https://doi.org/10.1081/TXR-120004744","url":null,"abstract":"Most snakebites in South America are caused by pitvipers (Bothrops, Crotalus and Lachesis spp.) and coral snakes (Micrurus spp.), with less serious accidents caused by colubrids. Rear-fanged species are responsible for most colubrid envenomations, the principal genera involved being Clelia, Helicops, Liophis, Philodryas, Tachymenis, and Thamnodynastes. The hands, feet and upper and lower limbs are bitten most frequently. Most envenomations are mild, involving mainly local pain, edema and ecchymosis. Systemic envenomation (altered whole blood clotting time, systemic bleeding, shock, and renal failure) is rare and only one fatality suspected to have been caused by a colubrid (P. olfersii in Brazil) has been recorded. Treatment is symptomatic and supportive, and recovery is generally uneventful, with no sequelae. The similarity between the local effects of envenomations by colubrids and those produced by South American lanceheads (Bothrops spp.) has resulted in bothropic antivenom being administered in several cases, but there is little conclusive evidence that antivenom enhanced the patients' condition. Together, these findings indicate that envenomations by South American colubrids are considerably less serious than those reported for certain African and Asian colubrids (Boiga, Dispholidus, Rhabdophis and Thelotornis spp.). However, the limited number of species involved in human envenomations to date compared to the large number of South American colubrids currently recognized suggests the need for caution in generalizing about the potential seriousness of bites by species not yet implicated in such accidents.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89667497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Buthid scorpion Leiurus quinquestriatus is divided into two sub-species whose region of contact occurs at the Suez Isthmus. L.q. quinquestriatus, found in the North Africa is distinguished from L.q. hebraeus by minor differences in morphology. Despite the very high similarity in body plan, out of the 24 toxins isolated from this species none is common to both sub-species, suggesting a degree of molecular divergence not apparent at the morphological level. We show, by comparison with two sets of reference proteins from humans and Old-World monkeys, that divergence of toxins with common structures and functions in these two sub-species has occurred under conditions of strong negative selection. Potential selection pressures responsible for toxin divergence are discussed, including the role of conflicting interests during courtship.
{"title":"TOXIN EVOLUTION IN SCORPION VENOM: EVIDENCE FOR TOXIN DIVERGENCE UNDER STRONG NEGATIVE SELECTION IN LEIURUS QUINQUESTRIATUS SUBSPECIES","authors":"A. Smertenko, M. Omran, P. Hussey, A. Mcvean","doi":"10.1081/TXR-100108558","DOIUrl":"https://doi.org/10.1081/TXR-100108558","url":null,"abstract":"The Buthid scorpion Leiurus quinquestriatus is divided into two sub-species whose region of contact occurs at the Suez Isthmus. L.q. quinquestriatus, found in the North Africa is distinguished from L.q. hebraeus by minor differences in morphology. Despite the very high similarity in body plan, out of the 24 toxins isolated from this species none is common to both sub-species, suggesting a degree of molecular divergence not apparent at the morphological level. We show, by comparison with two sets of reference proteins from humans and Old-World monkeys, that divergence of toxins with common structures and functions in these two sub-species has occurred under conditions of strong negative selection. Potential selection pressures responsible for toxin divergence are discussed, including the role of conflicting interests during courtship.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78803675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Malir, T. Roubal, M. Brndiar, J. Osterreicher, J. Severa, J. Knížek, J. Kačerovský, M. Tmĕjová, A. Betbeder, I. Baudrimont, E. Creppy
Ochratoxin A (OTA) was found in cereals in the former Czechoslovakia as early as 1978. It was even the cause of mycotoxic nephropathy in pigs in a farm in the second half of the 1970s. Since then OTA has been monitored by the health authorities of Czechoslovakia and now the Czech Republic. OTA was detected in samples of various foodstuffs e.g. composite samples of cereals, pastry, coffee and raisins. OTA was also found in the blood serum of blood donors. A recent study of the accumulation of OTA in patients with chronic renal insufficiency (CHRI) has demonstrated that unlike in the control group of blood donors, the retention of OTA is significant in outpatients with stabilized CHRI and patients in the terminal stage of CHRI (who are regularly treated by dialysis). Because of the nephrotoxicity of OTA, such a retention may accelerate their disease. The study has also shown that a standard dialysis did not result in the decrease of OTA serum levels. Findings of OTA in biological materials have proven that the Czech population is exposed to this toxin to a certain degree.
{"title":"OCHRATOXIN A IN THE CZECH REPUBLIC","authors":"F. Malir, T. Roubal, M. Brndiar, J. Osterreicher, J. Severa, J. Knížek, J. Kačerovský, M. Tmĕjová, A. Betbeder, I. Baudrimont, E. Creppy","doi":"10.1081/TXR-100108560","DOIUrl":"https://doi.org/10.1081/TXR-100108560","url":null,"abstract":"Ochratoxin A (OTA) was found in cereals in the former Czechoslovakia as early as 1978. It was even the cause of mycotoxic nephropathy in pigs in a farm in the second half of the 1970s. Since then OTA has been monitored by the health authorities of Czechoslovakia and now the Czech Republic. OTA was detected in samples of various foodstuffs e.g. composite samples of cereals, pastry, coffee and raisins. OTA was also found in the blood serum of blood donors. A recent study of the accumulation of OTA in patients with chronic renal insufficiency (CHRI) has demonstrated that unlike in the control group of blood donors, the retention of OTA is significant in outpatients with stabilized CHRI and patients in the terminal stage of CHRI (who are regularly treated by dialysis). Because of the nephrotoxicity of OTA, such a retention may accelerate their disease. The study has also shown that a standard dialysis did not result in the decrease of OTA serum levels. Findings of OTA in biological materials have proven that the Czech population is exposed to this toxin to a certain degree.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84156878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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