Snake Venomic of Crotalus durissus terrificus-Correlation with Pharmacological Activities

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Snake venomics of the Siamese Russell's viper (Daboia russelli siamensis) - Relation to pharmacological activities

The venom proteome of Daboia russelli siamensis, a snake of medical importance in several Asian countries, was analysed by 2-D electrophoresis, subsequent MS/MS and enzymatic assays. The proteome comprises toxins from six protein families: serine proteinases, metalloproteinases, phospholipases A(2), L-amino acid oxidases, vascular endothelial growth factors and C-type lectin-like proteins. The venom toxin composition correlates with the clinical manifestation of the Russell's viper bite and explains pathological effects of the venom such as coagulopathy, oedema, hypotensive, necrotic and tissue damaging effects. The vast majority of toxins are potentially involved in coagulopathy and neurotoxic effects. The predominant venom components are proteinases capable of activating blood coagulation factors and promoting a rapid clotting of the blood, and neurotoxic phospholipase A(2)s. The analysis of the venom protein composition provides a catalogue of secreted toxins. The proteome of D. r. siamensis exhibits a lower level of toxin diversity than the proteomes of other viperid snakes. In comparison to the venoms of Vipera ammodytes ammodytes and Vipera ammodytes meridionalis, the venom from D. r. siamensis showed quantitative differences in the proteolytic, phospholipase A2, L-amino acid oxidase and alkaline phosphatase activities. (c) 2009 Published by Elsevier B.V.

Purification, crystallization and preliminary X-ray diffraction analysis of crotamine, a myotoxic polypeptide from the Brazilian snake Crotalus durissus terrificus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Suitability of DNA extracted from archival specimens of fruit-eating bats of the genus Artibeus (Chiroptera, Phyllostomidae) for polymerase chain reaction and sequencing analysis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of eating disorders on oral fungal diversity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural and functional characterization of neuwiedase, a nonhemorrhagic fibrin(ogen)olytic metalloprotease from Bothrops neuwiedi snake venom

A fibrino(geno)lytic nonhemorrhagic metalloprotease (neuwiedase) was purified from Bothrops neuwiedi snake venom by a single chromatographic step procedure on a CM-Sepharose column, Neuwiedase represented 4.5% (w/w) of the crude desiccated venom, with an approximate Mr of 20,000 and pI 5.9, As regards the amino acid composition, neuwiedase showed similarities with other metalloproteases, with high proportions of Asx, Glx, Leu, and Ser, Atomic absorption spectroscopy showed that one mole of Zn2+ and one mole of Ca2+ were present per mole olf protein. The cDNA encoding neuwiedase was isolated by RT-PCR from venom gland RNA, using oligonucleotides based on the partially determined amino-acid sequences of this metalloprotease. The fall sequence contained approximately 594 bp, which codified the 198 amino acid residues with an estimated molecular weight of 22,375. Comparison of the nucleotide and amino acid sequences of neuwiedase with those of other snake venom metalloproteases showed a high level of sequential similarity, Neuwiedase has two highly conserved characteristics sequences H(142)E(143)XXH(146)XXG(140)XXH(152) and C164I165M166. The three-dimensional structure of neuwiedase was modeled based on the crystal structure of Crotalus adamanteus Adamalysin II. This model revealed that the zinc binding site region showed a I high structural similarity with other metalloproteases,, the proteolyitc specificity, using the B beta-chain of oxidized insulin as substrate, was shown to be directed to the Ala(14)-Leu(15) and Tyr(16)-Leu(17) peptide bonds which were preferentially hydrolyzed. Neuwiedase is a A alpha,B beta fibrinogenase, Its activity upon the A alpha chain of fibrinogen was detected within 15 min of incubation. The optimal temperature and pH for the degradation of both A alpha and B beta chains were 37 degrees C and 7.4-8.0, respectively. This activity was inhibited by EDTA and 1,10-phenantroline, Neuwiedase also showed proteolytic activity upon fibrin and some components of the extracellular matrix. However, it did not show TAME esterase activity and was not able to inhibit platelet aggregation. (C) 2000 Academic Press.

Temperature and meal size effects on the postprandial metabolism and energetics in a boid snake

We investigated the combined effect of meal size and temperature on the aerobic metabolism and energetics of digestion in Boa constrictor amarali. Oxygen uptake rates ((V) over dot o(2)) and the. duration of the digestion were determined in snakes fed with meals equaling to 5%, 10%, 20%, and 40% of the snake's body mass at 25degrees and 30 degreesC. The maximum (V) over dot o(2) values attained during digestion were greater at 30 degreesC than at 25 degreesC. Both maximal (V) over dot (o2) values and the duration of the specific dynamic action. (SDA) were attained sooner at 30 degreesC than at 25 degreesC. Therefore, the temperature effect on digestion in Boa is characterized by the shortening of the SDA duration at the expense of increased. Energy allocated to SDA was not affected by meal size but. was greater at 25 degreesC compared to 30 degreesC. This indicates that a postprandial thermophilic response can be advantageous not only by decreasing the duration of digestion but also by improving digestive efficiency. Maximal (V) over dot o(2) and SDA duration. increased with meal size at both temperatures.

Water collection by the body in a viperid snake, Bothrops moojeni

We describe a previously unreported behavior for water collection in juveniles of a neotropical viperid snake. Bothrops moojeni. When sprayed over, this snake displays a stereotyped coiling, bringing its body loops in close contact with each other, so that water is retained between the loops and over the body surface. This water is continuously ingested during and after its collection. The functional significance of the water collecting behavior is suggested to be related with the acquisition of water from short rainfalls, and with the special climatic and geologic conditions of B. moojeni habitat. Rates of evaporative water loss did not differ between juvenile and adult snakes, but since juveniles have a greater surface-to-volume ratio, they were significantly more sensitive to desiccation than the adults.

Dissociation of enzymatic and pharmacological properties of piratoxins-I and -III, two myotoxic phospholipases A(2) from Bothrops pirajai snake venom

Piratoxins (PrTX) I and III are phospholipases A(2) (PLA(2)s) or PLA(2) homologue myotoxins isolated from Bothrops pirajai snake venom, which also induce myonecrosis, bactericidal activity against Escherichia coli, disruption of artificial membranes, and edema. PrTX-III is a catalytically active hemolytic and anticoagulant Asp49 PLA(2), while PrTX-I is a Lys49 PLA, homologue, which is catalytically inactive on artificial substrates, but promotes blockade of neuromuscular transmission. Chemical modifications of His, Lys, Tyr, and Trp residues of PrTX-I and PrTX-III were performed, together with cleavage of the N-terminal octapeptide by CNBr and inhibition by heparin and EDTA. The lethality, bactericidal activity, myotoxicity, neuromuscular effect, edema inducing effect, catalytic and anticoagulant activities, and the liposome-disruptive activity of the modified toxins were evaluated. A complex pattern of functional differences between the modified and native toxins was observed. However, in general, chemical modifications that significantly affected the diverse pharmacological effects of the toxins did not influence catalytic or membrane disrupting activities. Analysis of structural changes by circular dichroism spectroscopy demonstrated significant changes in the secondary structure only in the case of N-terminal octapeptide cleavage. These data indicate that PrTX-I and PrTX-III possess regions other than the catalytic site, which determine their toxic and pharmacological activities. (C) 2001 Academic Press.

Attraction of the fruit-eating bat Carollia perspicillata to Piper gaudichaudianum essential oil

We performed field tests using mimetic Piper fruits with and without essential oil extracted through hydrodistillation from Piper gaudichaudianum ripe fruits in order to evaluate the role of odor in Carollia perspicillata attraction and capture in mist-nets. During the field tests, 26 C. perspicillata were captured, 21 (80.7%) in nets with the essential oil of P. gaudichaudianum and five (19.3%) in nets without oil. Other bat species, Artibeus spp. ( 67), which is specialized on fruits of Moraceae, and Sturnira lilium ( 10), specialized on those of Solanaceae, were also captured, but they exhibited no significant preference for nets with or without oil. We conclude that odor is pre-eminent over visual cues in food location by C. perspicillata in a field situation. Based on the result, we propose the extraction and use of essential oils of chiropterochoric fruits as a useful approach to improve autoecological studies on fruit-eating bats and to promote tropical forest restoration through the attraction of frugivorous bats to degraded areas.