- Envenomation by an opisthoglyphous snake, Erythrolamprus aesculapii (Dipsadidae), in southeastern Brazil. [Case Reports]
- RSRev Soc Bras Med Trop 2019 May 30; 52:e20190055
- Snakebites by aglyphous or opisthoglyphous snakes are common in Brazil. We report a case of snakebite by the opisthoglyphous Erythrolamprus aesculapii. The victim presented with pain, edema, and blee…
Snakebites by aglyphous or opisthoglyphous snakes are common in Brazil. We report a case of snakebite by the opisthoglyphous Erythrolamprus aesculapii. The victim presented with pain, edema, and bleeding at the bite site, along with erythema, similar to a Bothrops envenomation. In this type of snakebite, if the snake is not brought to the hospital, the victim may receive unnecessary serum therapy, with the risk of adverse reactions to the antivenom. The possibility of reducing after-effects with anti-inflammatory drugs and early antibiotic therapy for secondary infection need to be further investigated, preferably in multicenter studies, while observing good clinical practice.
- A case of envenomation by neotropical Opisthoglyphous snake Thamnodynastes pallidus (Linnaeus, 1758) (Colubridae: Dipsadinae: Tachymenini) in Brazil. [Case Reports]
- RIRev Inst Med Trop Sao Paulo 2018 Jul 30; 60:e38
- This is a case report of a bite by an Opisthoglyphous snake Thamnodynastes pallidus (Linnaeus, 1758) in an undergraduate herpetologist observed at the Universidade Federal da Paraiba (Rio Tinto, PB, …
This is a case report of a bite by an Opisthoglyphous snake Thamnodynastes pallidus (Linnaeus, 1758) in an undergraduate herpetologist observed at the Universidade Federal da Paraiba (Rio Tinto, PB, Brazil). The female victim was bitten in her left hand between the index finger and the middle finger and presented symptoms of local envenomation such as bleeding, itching, pain in the wound and swelling. The patient was first seen at the University and afterwards at home during the 36 hours following the incident, when the symptoms disappeared. This is the first case report of an accident by T. pallidus in a human being in Brazil.
- Biochemical characterization of venom from Pseudoboa neuwiedii (Neuwied's false boa; Xenodontinae; Pseudoboini). [Journal Article]
- CBComp Biochem Physiol C Toxicol Pharmacol 2018; 213:27-38
- In this work, we examined the proteolytic and phospholipase A2 (PLA2) activities of venom from the opisthoglyphous colubrid Pseudoboa neuwiedii. Proteolytic activity (3 and 10 μg of venom) was compar…
In this work, we examined the proteolytic and phospholipase A2 (PLA2) activities of venom from the opisthoglyphous colubrid Pseudoboa neuwiedii. Proteolytic activity (3 and 10 μg of venom) was comparable to that of Bothrops neuwiedii venom but less than Bothrops atrox. This activity was inhibited by EDTA and 1,10-phenanthroline but only slightly affected (≤30% inhibition) by PMSF and AEBSF, indicating it was mediated by snake venom metalloproteinases (SVMPs). The pH and temperature optima for proteolytic activity were 8.0 and 37 °C, respectively. The venom had no esterase activity, whereas PLA2 activity was similar to B. atrox, greater than B. neuwiedii but less than B. jararacussu. SDS-PAGE revealed venom proteins >100 kDa, 45-70 kDa, 21-24 kDa and ~15 kDa, and mass spectrometry of protein bands revealed SVMPs, cysteine-rich secretory proteins (CRISPs) and PLA2, but no serine proteinases. In gelatin zymography, the most active bands occurred at 65-68 kDa (seen with 0.05-0.25 μg of venom). Caseinolytic activity occurred at 50-66 kDa and was generally weaker than gelatinolytic activity. RP-HPLC of venom yielded 15 peaks, five of which showed gelatinolytic activity; peak 7 was the most active and apparently contained a P-III class SVMP. The venom showed α-fibrinogenase activity, without affecting the β and γ chains; this activity was inhibited by EDTA and 1,10-phenanthroline. The venom did not clot rat citrated plasma but reduced the rate and extent of coagulation after plasma recalcification. In conclusion, P. neuwiedii venom is highly proteolytic and could potentially affect coagulation in vivo by degrading fibrinogen via SVMPs.
- Local and hematological alterations induced by Philodryas olfersii snake venom in mice. [Journal Article]
- TToxicon 2017 Jun 15; 132:9-17
- Envenomation by the South American opisthoglyphous snake Philodryas olfersii causes local pain, edema, erythema and ecchymosis; systemic envenomation is rare. In this work, we examined the inflammato…
Envenomation by the South American opisthoglyphous snake Philodryas olfersii causes local pain, edema, erythema and ecchymosis; systemic envenomation is rare. In this work, we examined the inflammatory activity of P. olfersii venom (10, 30 and 60 μg) in mouse gastrocnemius muscle 6 h after venom injection. Intramuscular injection of venom did not affect hematological parameters such as red cell count, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The venom caused thrombocytopenia (at all three doses), leukopenia and lymphopenia (both at the two highest doses), as well as neutrophilia (30 μg), monocytosis (30 μg) and basophilia (10 μg). Of the cytokines that were screened [IL-1β, IL-6, IL-10, IL-13, IL-17, TNF-α, IFN-γ, MIP-2 and KC] and IGF-1, only IGF-1 showed a significant increase in its circulating concentration, seen with 60 μg of venom; there were no significant changes in the cytokines compared to control mice. Histological analysis revealed the presence of edema, an inflammatory infiltrate and progressive myonecrosis. Edema and myonecrosis were greatest with 60 μg of venom, while the inflammatory infiltrate was greatest with 10 μg of venom. All venom doses caused the migration of polymorphonuclear and mononuclear leukocytes into muscle, but with no significant dose-dependence in the response. These findings show that, at the doses tested, P. olfersii venom does not cause hematological alterations and has limited effect on circulating cytokine concentrations. These data also confirm that the principal effects of the venom in mice are local edema, inflammatory cell infiltration and myonecrosis.
- Comparing species tree estimation with large anchored phylogenomic and small Sanger-sequenced molecular datasets: an empirical study on Malagasy pseudoxyrhophiine snakes. [Journal Article]
- BEBMC Evol Biol 2015 Oct 12; 15:221
- CONCLUSIONS: Our results suggest that ≥50 loci may be necessary to confidently infer phylogenies when using summaryspecies-tree methods, but that the coalescent-based method *BEAST consistently recovers the same topology using only 15 loci. These results reinforce that datasets with small numbers of markers may result in misleading topologies, and further, that the method of inference used to generate a phylogeny also has a major influence on the number of loci necessary to infer robust species trees.
- First reported case of systemic envenoming by the Sri Lankan keelback (Balanophis ceylonensis). [Case Reports]
- TToxicon 2015; 93:20-3
- Envenoming by colubrid snakes is rarely reported. However, some colubrid snakes (e.g. Rhabdophis tigrinus and Rhabdophis subminiatus) have caused severe systemic envenoming. We report here the first …
Envenoming by colubrid snakes is rarely reported. However, some colubrid snakes (e.g. Rhabdophis tigrinus and Rhabdophis subminiatus) have caused severe systemic envenoming. We report here the first case of a bite with systemic envenoming by Balanophis ceylonensis, an opisthoglyphous natricine colubrid, in Sri Lanka. A 33-year-old healthy male field biologist was bitten while handling the snake for photography. Within 5 min of the bite on the dorsum of the right hand, he reported severe occipital headache, photophobia, chills and transient loss of consciousness. He vomited blood-stained gastric contents and bled from venepuncture sites. He had a markedly elevated INR and positive D-dimer test suggestive of significant coagulopathy that was treated with infusions of fresh frozen plasma. He recovered and left hospital after 96 h and subsequent investigations, including electroencephalogram, were normal. We conclude that B. ceylonensis should be regarded as a medically significant venomous snake. This case highlights the need for further studies of the oral secretions (venoms) of colubrid snakes.
- Biochemical and biological analysis of Philodryas baroni (Baron's green racer; Dipsadidae) venom: relevance to the findings of human risk assessment. [Journal Article]
- HEHum Exp Toxicol 2014; 33(1):22-31
- Philodryas baroni--an attractively colored snake--has become readily available through the exotic pet trade. Most people consider this species harmless; however, it has already caused human envenomat…
Philodryas baroni--an attractively colored snake--has become readily available through the exotic pet trade. Most people consider this species harmless; however, it has already caused human envenomation. As little is known about the venom from this South American opisthoglyphous "colubrid" snake, herein, we studied its protein composition by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), as well as its effects on the hemostatic system. Both reducing and nonreducing SDS-PAGE analysis demonstrated that the venom exhibits greatest complexity in the range of 50-80 kDa. The venom displayed proteolytic activity toward azocollagen, with a specific activity of 75.5 U mg⁻¹, and rapidly hydrolyzed the Aα-chain of fibrinogen, exhibiting lower activity toward the Bβ- and γ-chains. The venom from P. baroni showed no platelet proaggregating activity per se, but it inhibited collagen- and thrombin-induced platelet aggregation. Prominent hemorrhage developed in mouse skin after intradermal injection of the crude venom, and its minimum hemorrhagic dose was 13.9 μg. When injected intramuscularly into the gastrocnemius of mice, the venom induced local effects such as hemorrhage, myonecrosis, edema, and leucocyte infiltration. Due to its venom toxicity shown herein, P. baroni should be considered dangerous to humans and any medically significant bite should be promptly reviewed by a qualified health professional.
- Resolving an enigma by integrative taxonomy: Madagascarophis fuchsi (Serpentes: Lamprophiidae), a new opisthoglyphous and microendemic snake from northern Madagascar. [Journal Article]
- ZZootaxa 2013; 3630:317-32
- Herpetological surveys in the dry forests of the limestone massif Montagne des Français in the far north of Madagascar have recently yielded a number of undescribed reptile species. Here we describe …
Herpetological surveys in the dry forests of the limestone massif Montagne des Français in the far north of Madagascar have recently yielded a number of undescribed reptile species. Here we describe an additional new and potentially microendemic species of the snake genus Madagascarophis (Squamata: Serpentes: Pseudoxyrhophiinae) which lives in this massif syntopically with M. colubrinus septentrionalis and differs distinctly from M. colubrinus and M. meridionalis in its mitochondrial and nuclear DNA sequences. Morphologically Madagascarophis fuchsi sp. nov. is characterized by a broad contact between the posterior inframaxillaries (genials), 25 dorsal scale rows at midbody, and a low number of ventrals (171-172). We redescribe the holotype of M. ocellatus and present new data on the morphological variation of the northern subspecies M. c. septentrionalis and M. c. citrinus. Although Montagne des Français has recently been included into the network of nature reserves in Madagascar, continuous deforestation is strongly threatening this important center of reptile endemism. In line with the assessment of other microendemic reptiles of this massif we suggest to consider the new species as Critically Endangered according to the IUCN criteria and encourage new efforts to protect this area more efficiently.
- Venom proteomes of South and North American opisthoglyphous (Colubridae and Dipsadidae) snake species: a preliminary approach to understanding their biological roles. [Journal Article]
- CBComp Biochem Physiol Part D Genomics Proteomics 2012; 7(4):361-9
- Opisthoglyphous snake venoms remain under-explored despite being promising sources for ecological, evolutionary and biomedical/biotechnological research. Herein, we compared the protein composition a…
Opisthoglyphous snake venoms remain under-explored despite being promising sources for ecological, evolutionary and biomedical/biotechnological research. Herein, we compared the protein composition and enzymatic properties of the venoms of Philodryas baroni (PbV), Philodryas olfersii olfersii (PooV) and Philodryas patagoniensis (PpV) from South America, and Hypsiglena torquata texana (HttV) and Trimorphodon biscutatus lambda (TblV) from North America. All venoms degraded azocasein, and this metalloproteinase activity was significantly inhibited by EDTA. PooV exhibited the highest level of catalytic activity towards synthetic substrates for serine proteinases. All venoms hydrolyzed acetylthiocholine at low levels, and only TblV showed phospholipase A(2) activity. 1D and 2D SDS-PAGE profile comparisons demonstrated species-specific components as well as several shared components. Size exclusion chromatograms from the three Philodryas venoms and HttV were similar, but TblV showed a notably different pattern. MALDI-TOF MS of crude venoms revealed as many as 49 distinct protein masses, assigned to six protein families. MALDI-TOF/TOF MS analysis of tryptic peptides confirmed the presence of cysteine-rich secretory proteins in all venoms, as well as a phospholipase A(2) and a three-finger toxin in TblV. Broad patterns of protein composition appear to follow phylogenetic lines, with finer scale variation likely influenced by ecological factors such as diet and habitat.
New Search Next
- Neuromuscular action of venom from the South American colubrid snake Philodryas patagoniensis. [Journal Article]
- CBComp Biochem Physiol C Toxicol Pharmacol 2008; 148(1):31-8
- Snakes of the opisthoglyphous genus Philodryas are widespread in South America and cause most bites by colubrids in this region. In this study, we examined the neurotoxic and myotoxic effects of veno…
Snakes of the opisthoglyphous genus Philodryas are widespread in South America and cause most bites by colubrids in this region. In this study, we examined the neurotoxic and myotoxic effects of venom from Philodryas patagoniensis in biventer cervicis and phrenic nerve-diaphragm preparations and we compared the biochemical activities of venoms from P. patagoniensis and Philodryas olfersii. Philodryas patagoniensis venom (40 microg/mL) had no effect on mouse phrenic nerve-diaphragm preparations but caused time-dependent neuromuscular blockade of chick biventer cervicis preparations. This blockade was not reversed by washing. The highest concentration of venom tested (40 microg/mL) significantly reduced (p<0.05) the contractures to exogenous acetylcholine (55 microM and 110 microM) and K(+) (13.4 mM) after 120 min; lower concentrations of venom had no consistent or significant effect on these responses. Venom caused a concentration- and time-dependent release of creatine kinase (CK) from biventer cervicis preparations. Histological analysis showed contracted muscle fibers at low venom concentrations and myonecrosis at high concentrations. Philodryas venoms had low esterase and phospholipase A(2) but high proteolytic activities compared to the pitviper Bothrops jararaca. SDS-PAGE showed that the Philodryas venoms had similar electrophoretic profiles, with most proteins having a molecular mass of 25-80 kDa. Both of the Philodryas venoms cross-reacted with bothropic antivenom in ELISA, indicating the presence of proteins immunologically related to Bothrops venoms. RP-HPLC of P. patagoniensis venom yielded four major peaks, each of which contained several proteins, as shown by SDS-PAGE. These results indicate that P. patagoniensis venom has neurotoxic and myotoxic components that may contribute to the effects of envenoming by this species.