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PubMed1989

A Golgi study on the main olfactory bulb in the snake Elaphe quadrivirgata.

The intrinsic organization of the main olfactory bulb in the snake was studied using the rapid Golgi method. A distinct laminar structure was recognized. From the periphery inward, the following layers were distinguished: the layer of the olfactory fibers, the olfactory glomeruli, the mitral cells, the deep fiber plexus, the granule cells and the ependymal cells. Olfactory fibers derived from the nasal cavity reached the entire surface of the bulb, forming a dense fiber plexus, then swung deeply and terminated in the olfactory glomeruli which were arranged in 2-4 rows. The mitral cell layer occupied a wide zone and was composed of scattered mitral cells. The mitral cells had 2-9 primary dendrites proceeding externally to terminate in the olfactory glomeruli and 2-4 secondary dendrites extending tangentially in the mitral cell layer to be distributed therein. The axons of the mitral cells travelled deeply and entered the layer of the deep fiber plexus. The deep fiber plexus was the path for the bulbar efferent and afferent fibers and could be traced caudally as the main olfactory tract, up to the anterior olfactory nucleus and vicinity. The granule cell layer was composed of small cells, the granule cells, packed closely with no special arrangement. The granule cells had long processes which extended superficially to be distributed mainly in the mitral cell layer. The ependymal cells were located at the deepest layer forming the wall of the olfactory ventricle and generated a long process which extended towards the surface to terminate in the peripheral portion of the bulb. In the snake bulb, the well-documented external and internal plexiform layers were considered to be included in the wide mitral cell layer. Thus, while several specific structures were observed, the fundamental organization of the main olfactory bulb in the snake seemed to be identical to that of the main olfactory bulb in various other vertebrate species.

Animals↗
PubMed1987

Pyrogens fail to produce fever in the snakes Psammophis phillipsii and Lamprophis fuliginosus.

1. Preferred body temperature of five diurnal, Psammophis philipsii and three nocturnal, Lamprophis fuliginosus, snakes was measured in a thermal gradient chamber by indwelling colonic thermocouples, before and after injection of a variety of pyrogens. 2. The snakes achieved their preferred body temperature by moving up and down in the gradient chamber; it was about 33 degrees C for P. phillipsii and 25 degrees C for L. fuliginosus. 3. The snakes did not develop fever in response to any of the pyrogens, whether gram-negative or gram-positive in origin, either on the day of injection or on the subsequent day. 4. We believe that fever is rare amongst reptiles.

Animals↗
PubMed1987

Hibernation in garter snakes (Thamnophis sirtalis parietalis): seasonal cycles of cold tolerance.

1. The red-sided garter snake hibernates for about six months each year in Manitoba, Canada, where winter temperatures are often as low as -40 degrees C. Mammalian hibernators typically undergo profound changes in preparation for hibernation, but little is known about corresponding changes in reptiles. 2. We tested the importance of seasonal changes in the ability of red-sided garter snakes to hibernate successfully by exposing them to winter conditions at different times of year. 3. Animals that began hibernation in the fall were more likely to survive hibernation than animals that began hibernation in either early or late summer, despite the fact that the animals were kept on seasonally constant conditions prior to hibernation. 4. We suggest that these changes are derived from endogenous components of the yearly hibernation cycle of red-sided garter snakes but that only part of the cycle proceeds endogenously, i.e. it is not a completely endogenous circannual cycle.

Acclimatization↗
PubMed1985

Physical properties of some snake plasma albumins.

The albumin-like proteins were purified from the plasma of three terrestrial elapids and two sea snakes. The albumin-like fraction averaged 25% (range: 21-30%) in concentration of the total plasma proteins as determined by densitometer. The physical properties of the albumin-like proteins purified from these snakes were compared. These properties, e.g. electrophoretic mobility, isoelectric point, extinction coefficient, and molecular weight, were shown to be strikingly similar to those of human plasma albumin. The physical properties of the plasma albumins of the snakes studied are similar to one another. This similarity does not explain our previous observation that Naja albumin is considerably remote immunologically from those of other elapids (Mao et al., 1983).

Animals↗
PubMed1992

Immunological analysis of chemoattractive proteins from earthworm to garter snakes.

1. Two sets of polyclonal antibodies to two highly purified prey-derived snake-attractive proteins, a low molecular weight (3000) protein and a 20,000 mol. wt protein, were generated in rabbits. 2. They are immunospecific for their respective purified immunogens and do not cross-react with each other. 3. Eight prey-derived proteins that elicit attack by garter snakes (Thamnophis sirtalis) from earthworms (Lumbricus terrestris) were analyzed with these antibodies, and can be assigned to three distinct groups on the basis of their antigenic properties. 4. Unfolding or denaturation of the low molecular weight protein did not alter its antigenic activity to its polyclonal antibodies, suggesting the antigenic epitopes contain contiguous amino acid sequences. 5. In contrast, unfolding of the 20,000 mol. wt protein resulted in a loss of its binding with antibodies, suggesting that the epitope of this protein contains noncontiguous amino acid sequences. 6. The snake-attractivity of the 20,000 mol. wt protein could not be neutralized by reacting it with its antiserum, suggesting that the antigenic determinant (the epitope) of the antigen is not an integral part of the attractive domain of the ES20 protein. 7. In contrast, the attractivity of the purified low molecular weight protein could be neutralized by the polyclonal antibodies.

Animals↗
PubMed1992

Electrophoretic analysis of snake venoms.

Electrophoretic analyses were conducted on snake venoms from 21 species representing Elapidae, Crotalidae and Viperidae. Denatured and native venoms were analyzed by polyacrylamide gel electrophoretic (PAGE) methods with sodium dodecyl sulfate (SDS) and without SDS. Both SDS-PAGE and PAGE profiles of venoms from different snake species indicate that some proteins and polypeptide components of these venoms have common electrophoretic characteristics suggesting a genetic relationship. Conversely, the electropherograms also showed the characteristic protein and polypeptide profiles that could differentiate one snake species from another. Therefore, both SDS-PAGE and PAGE profiles suggest that proteins and polypeptides with similar characteristics abound among subspecies or related species, although each venom has a unique profile that differentiates one species from the other.

Animals↗
PubMed1989

Apparent coral snake envenomation in a patient without visible fang marks.

Envenomation by the North American coral snake is an uncommon entity in the United States. In most cases fang marks will be present, although they may be quite small and difficult to see. The case of a young man who demonstrated evidence of envenomation following the bite of a Texas coral snake (Micrurus fulvius tenere), despite the absence of any apparent fang marks on close examination, is reported. The problems associated with coral snake envenomation in terms of diagnosis and management are reviewed.

Adult↗
PubMed2004

Optical immunoassay for snake venom detection.

A sensitive and specific optical immunoassay (OIA) has been developed for snake venom detection. The assay is based on the principle of detection of physical changes in thickness of molecular thin film resulting from specific binding events on an optical silicon chip (SILAS-I, ThermoBioStar, Colorado, USA). The reflection of white light through the thin film results in destructive interference of a particular wavelength of the light from gold to purple-blue depending on the thickness of the thin film formed or the amount of venom in the test sample. A prototype test kit for the simultaneous identification of species and semi-quantitative detection of venoms from four medically important snakes of South Vietnam (Trimeresurus albolabris, Calloselasma rhodostoma, Naja kaouthia and Ophiophagus hannah) has been developed. The kit can detect venom analytes in blood, plasma, urine, wound exudates, blister fluid or tissue homogenates. The efficacy of the test kit in snakebite diagnosis has been demonstrated in experimental envenomations and sample analytes taken from snakebite victims in South Vietnam. This rapid snake venom detection kit based on OIA technique is potentially applicable in the clinics as well as in the field.

Animals↗
PubMed2005

A case of fatal progressive neuropathy. Delayed consequence of multiple bites of a non-venomous snake?

Neurotoxicity is a common feature of the acute syndrome of systemic snake envenomation. In this report a patient with delayed onset of neurological manifestations after multiple bites of a non-venomous snake is described. The neurological cascade consisted of segmental painful muscle spasms presented several days after the snake bites, which gradually subsided and within a month was followed by muscle weakness in the legs. The latter progressed to flaccid quadriplegia with additional respiratory and autonomic failure leading to death after total disease duration of 5.5 months. The possibility that this unique neurological syndrome of fatal progressive neuropathy could be caused by either tetanus or an immune reaction initiated by snakebites is discussed.

Aged↗
PubMed2005

Anticoagulant and antifibrinogenolytic properties of the aqueous extract from Bauhinia forficata against snake venoms.

The aqueous extract from aerial parts of Bauhinia forficata was able to neutralize the clotting activity induced by Bothrops and Crotalus crude venoms. The clotting time, upon human plasma, induced by B. moojeni venom was significantly prolonged. Clotting and fibrinogenolytic activities induced by isolated thrombin-like enzyme from Bothrops jararacussu were totally inhibited after incubation at different ratios. The extract was not able to neutralize the hemorrhagic activity induced by an Bothrops venoms, but it efficiently inhibited the edema induced by Crotalus durissus terrificus venom and isolated PLA2s. In addition, it did not inhibited the phospholipase A2 activity of Bothrops snake venoms. Interaction studies between Bauhinia forficata extract and snake venoms, when analyzed by SDS-PAGE, did not reveal any apparent degradation of the venom proteins. This extract is a promising source of natural inhibitors of serine-proteases involved in blood clotting disturbances induced by snake venoms.

Animals↗
PubMed2006

Isolation and pharmacological characterisation of hostoxin-1, a postsynaptic neurotoxin from the venom of the Stephen's banded snake (Hoplocephalus stephensi).

Envenoming by the Stephen's banded snake (Hoplocephalus stephensi) is not usually characterised by neurotoxicity. The present study describes the pharmacological characterisation of hostoxin-1 (MW 6660 Da), the first neurotoxin to be isolated from the venom of the Stephen's banded snake. Hostoxin-1 (0.3-1.0 microM) caused concentration-dependent inhibition of indirect twitches of the chick biventer cervicis nerve-muscle preparation. The neurotoxic activity of hostoxin-1 (0.3 microM) was irreversible by washing, but significantly reversed by the addition of CSL tiger snake antivenom (5 units/ml) added at t90 (i.e. time at which twitches were inhibited by 90%). In addition, hostoxin-1 (0.3 microM) inhibited responses to exogenous acetylcholine and carbachol, but not KCl, indicating a postsynaptic mode of action. Hostoxin-1 (5-30 nM) displayed pseudo-irreversible antagonism at the skeletal muscle nicotinic receptor with a pA2 value of 8.45+/-0.32 (i.e. approximately 100-fold more potent than tubocurarine). H. stephensi venom displayed a high level of PLA2 activity (specific activity 100.1+/-4.4 micromol/min/mg). However, the activity of hostoxin-1 was negligible. Partial N-terminal sequencing of hostoxin-1 indicates that it has high sequence homology with other elapid short-chain neurotoxins.

Analysis of Variance↗
PubMed2004

Identification and cloning of snake venom vascular endothelial growth factor (svVEGF) from Bothrops erythromelas pitviper.

Vascular endothelial growth factors (VEGFs) are among the most important angiogenic proteins found on vertebrates. In the last years, some reports of the occurrence of such proteins in snake venoms are rising the importance of this family of proteins as toxins, since they appear to be involved in many features of Viperidae envenoming, such as hypotension and venom spread through increase in vascular permeability. Here we describe the occurrence of snake venom VEGF in Bothrops erythromelas, a clinical important snake from Northeast of Brazil, through immunodetection and cloning of its cDNA and briefly provide an overview comparison of all recent described svVEGF sequences.

Animals↗
PubMed2005

Functional, cellular and molecular aspects of skeletal muscle recovery after injury induced by snake venom from Notechis scutatus scutatus.

We have analysed the rate and ultimate extent of muscle functional recovery after snake venom-induced myotoxicity, as well as the relationships between functional, biochemical and structural indices of recovery. We also compared the effects of various injuries leading to muscle necrosis, loss of innervation/vasculature and/or precursors of muscle cells (pmc). We found that several parameters of rat soleus muscle such as maximal isometric force, slow myosin heavy chain, and citrate synthase, were fully and rapidly restored within 6 weeks after treatment with snake Notechis scutatus venom (im, 2 microg/muscle). In contrast, some muscle contractile properties (degree of tetanic fusion, fatigue resistance...) were not fully recovered even by 12 weeks after venom treatment. However, when compared to other injuries, recovery 3 weeks after venom treatment, was better than that observed after severing the terminal nerve and accompanying vessels and after cryodamage known to kill pmc. In conclusion, our studies demonstrate that-contrary to what is commonly believed -- muscle treated by myotoxic agent does not recover rapidly and fully. However, the degree or rate of muscle recovery after snake venom treatment was much better when compared to other types of injury. In addition, histological and biochemical parameters cannot be used as such to easily predict functional recovery following injury.

Animals↗
PubMed2005

Antibodies to a fragment of the Bothrops moojenil-amino acid oxidase cross-react with snake venom components unrelated to the parent protein.

It is widely accepted that immunological cross-reactivity of snake venoms is mediated by antibodies that recognize venom components bearing either amino acid sequence homology or similar biological functions. However, here we demonstrate that polyspecific Bothrops antivenom is a source of cross-reactive antibodies that interact with venom proteins of distinctive primary structures and biological functions. The homoserine lactone derivative of the undecapeptide IQRWSLDKYAM (Ile1-Hse11), excised from the l-amino acid oxidase (LAAO) of the Bothrops moojeni venom, was the ligand of an affinity resin used to isolate specific anti-Ile1-Hse11 antibodies which were instrumental in revealing immunological cross-reactivity among unrelated venom proteins. We examined the extent of the cross-reactivity of these antibodies by probing electroblots of venoms from representative snakes of genera Bothrops, Lachesis, Crotalus and Micrurus, and by unambiguous structural characterization of the affinity-purified proteins of B. moojeni venom recovered from an agarose-anti-Ile1-Hse11 column. Our results indicate that all venoms tested had at least three reactive components toward anti-Ile1-Hse11 antibodies, among which we identified two serine proteases, one phospholipase A2 homologue, and LAAO. We hypothesize that the cross-reactivity of the anti-Ile1-Hse11 antibodies to unrelated venom proteins derives from their mechanism of antigen recognition, whereby complementarity is achieved through reciprocal conformational adaptation of the reacting molecules. Also, we believe these findings have implications both in the development of improved antivenoms and the preparation of immunochemical reagents for diagnostic and scientific investigation purposes in the field of snake venoms.

4-Butyrolactone↗
PubMed2005

Biological activities of a lectin from Bothrops jararacussu snake venom.

Snake venoms contain saccharide-binding lectins. In this work, we examined the biological activities of a lectin (BjcuL) purified from Bothrops jararacussu snake venom by chromatography on non-derivatized Sepharose 4B and Sephacryl S-200 HR. The protein, a homodimer with subunits of 14.5 kDa, gave a single immunoprecipitin line in immunoelectrophoresis and cross-reacted in ELISA with antivenoms raised against Bothrops spp. (lanceheads), Micrurus spp. (coral snakes), Crotalus durissus terrificus (South American rattlesnake), and arthropod (Loxosceles gaucho, Phoneutria nigriventer and Tityus serrulatus) venoms. BjcuL agglutinated human formaldehyde-fixed erythrocytes at > or = 100 ng/ml and was inhibited by lactose and EDTA (> or = 2 mM) and high concentrations (> 100 mM) of glucose and sucrose, but not by N-acetylglucosamine. BjcuL had no direct hemolytic activity and was devoid of esterase, PLA2 and proteolytic activities. The lectin (up to 200 microg/ml) did not aggregate human platelet-rich plasma (PRP) or washed platelets (WP), nor did it alter the aggregation induced by ADP in PRP or by thrombin in WP. When injected into mouse hind paws, BjcuL (10-100 microg/paw) caused edema and increased vascular permeability, with a maximum effect after 1h that persisted for up to 6 h (edema) or gradually decreased after the peak interval (vascular permeability). No hemorrhage was observed in BjcuL-injected paws. In anesthetized rats, B. jararacussu venom (200 microg/kg, i.v.) produced sustained hypotension (maximum decrease of approximately 60%) whereas a similar dose of BjcuL decreased the blood pressure by approximately 15%, with a rapid return to the resting level.

Animals↗
PubMed2006

The anti-snake venom activities of the methanolic extract of the bulb of Crinum jagus (Amaryllidaceae).

The anti-snake venom activities of the methanolic extract of the bulb of Crinum jagus plant (Amaryllidaceae) were investigated in vitro and in vivo against the venoms of three notable snake species: Echis ocellatus, Bitis arietans and Naja nigricollis. The extract was prepared by cold marceration in 50% methanol at 37 degrees C with intermittent shaking for 48 h. An yield of 12.8% w/w dry extract was obtained. Oral administration of C. jagus extract (1000 mg/kg) protected 50% of mice, while injection of a 30 min pre-incubated mixture of the same dose of extract and venom gave 100% protection against the lethal effects of E. ocellatus venom (10 mg/kg, i.m.). The intraperitoneal administration of the extract at 250 mg/kg, 30 min before the injection of E. ocellatus venom (10mg/kg, i.m.), significantly (p<0.05) prolonged the death time of poisoned mice. C. jagus extract (500 mg/kg, per os), gave 50% protection against B. arietans venom (9.5mg/kg, i.m.) in mice while the pre-incubation of a mixture of the same dose of venom and extract (500 mg/kg), prior to injection (i.p.) of the mixture, gave only 33.3% protection. The pre-incubation of 500 mg/kg of C. jagus extract with N. nigricollis venom (6 mg/kg) prior to i.p. injection of the mixture protected 50% of the treated mice. There were generally no significant differences in the death times of mice that were given the same dose of the extract orally 30 min before injection of the venoms and those administered with the pre-incubated mixtures of venom and extract. The pre-incubation of the extract and E. ocellatus venom (5mg/kg) for 30 min, before the i.m. injection of the mixture, significantly reduced infiltration of inflammatory cells to the site of injection 4h post treatment. The concentrations of plasma creatine kinase in poisoned mice were significantly (p<0.01 or p<0.05) reduced after the injection (i.p.) of C. jagus extract (1000 mg/kg) pre-incubated with E. ocellatus (5mg/kg) or B. arietans (7 mg/kg) venom, respectively. The bulb extract of C. jagus blocked the haemorrhagic activity of a standard haemorrhagic dose (2.8 mg/ml) of E. ocellatus venom at various concentrations (1.7, 3.3 and 6.7 mg/ml). The methanolic bulb extract of C. jagus was therefore able to significantly protect mice from death, myonecrosis and haemorrhage induced by the lethal effects of venoms of notable snake species in Nigeria.

Animals↗
PubMed2026

Intraspecific variation in Bothrops neuwiedi snake venom: Influence of age and sex.

Snake venom is a complex mixture of molecules and is subject to intraspecific variations due to the influence of abiotic and/or biotic factors, one of which is the animal's ontogeny. Some studies have already shown the influence of age on the composition and properties of snake venom, but these variations are not uniform, and each species may exhibit a specific pattern of variation. Therefore, this study aimed to analyze the influence of age on the venom of Bothrops neuwiedi, using 5 age groups, differentiating between males and females. To this end, we analyzed the protein profile of these venoms (using SDS-PAGE, HPLC, and proteomic analyses); enzymatic activities (PLA2, LAAO, and proteolytic activities); coagulant activity, in vivo assays (MDH; LD50 and ED50), and immunorecognition tests (Western blotting and ELISA). Protein profile analysis showed that males exhibited a gradual increase in SVMP and PLA2 concentrations. Both sexes showed a decrease in CTL concentration and a loss of PLA2 activity, which occurred more gradually in males. Proteolytic activity did not show clear ontogenetic differences, but both sexes showed activity peaks in the 2-year-old and senile groups, with females exhibiting higher proteolytic activity than males. Regarding LAAO activity, it increased in males and decreased in females. Although the LD50 did not show age-dependent differences, the venom from the 1-year-old group took longer to cause death in mice but showed a higher hemorrhagic activity than seniles. Furthermore, more antivenom was needed to neutralize the venom from the 1-year-old group than the venom from the senile group; despite this, immunorecognition tests did not show significant ontogenetic variations. In conclusion, the venom of the snake B. neuwiedi undergoes ontogenetic variations with certain sexual differences, showing some peculiarities that have not been found in ontogenetic analyses of other species of the same genus.

Animals↗
PubMed2004

Failure of chloramphenicol prophylaxis to reduce the frequency of abscess formation as a complication of envenoming by Bothrops snakes in Brazil: a double-blind randomized controlled trial.

Bites by many species of venomous snake may result in local necrosis at, or extending from, the site of the bite. The use of prophylactic antibiotics to prevent infection as a complication of local necrotic envenoming is controversial. A double-blind randomized controlled trial was carried out to assess whether antibiotic therapy is effective in this situation. Two hundred and fifty-one patients, with proven envenoming by snakes of the genus Bothrops, admitted to two hospitals in Brazil, between 1990 and 1996, were randomized to receive either oral chloramphenicol (500 mg every six hours for five days) or placebo. One hundred and twenty-two of these patients received chloramphenicol (group 1) and 129 were given placebo (group 2). There were no significant differences between the groups at the time of admission. Necrosis developed in seven (5.7%) patients in group 1 and in five (3.9%) patients in group 2 (P>0.05) while abscesses occurred in six patients (4.9%) in group 1 and in six (4.7%) patients in group 2 (P>0.05). In conclusion, the use of orally-administered chloramphenicol for victims of Bothrops snake bite with signs of local envenoming on admission, is not effective for the prevention of local infections.

Abscess↗