Crystal structure of a phospholipase A(2) homolog complexed with p-bromophenacyl bromide reveals important structural changes associated with the inhibition of myotoxic activity

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

The Intriguing Phospholipases A(2) Homologues: Relevant Structural Features on Myotoxicity and Catalytic Inactivity

Phospholipases A(2) homologues are found in the venom of Crotalinae snakes, being their main action related to myonecrosis induction. Although many studies on these toxins had already been performed, their mechanism of action remains unclear. Here, important aspects about these toxins are reviewed, including their correct biological assembly and how essential is the natural substitution D49K for their catalytic inactivity.

Crystallization and preliminary X-ray diffraction studies of BmooPLA(2)-I, a platelet-aggregation inhibitor and hypotensive phospholipase A(2) from Bothrops moojeni venom

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

Crystallization and preliminary X-ray diffraction analysis of three myotoxic phospholipases A2 from Bothrops brazili venom

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

Early social environment and the fighting behaviour of young Oreochromis niloticus (Pisces, Cichlidae)

This study examines the influence of early experience with different forms of aggressive behaviour on the fighting behaviour of young fish. Fry of the cichlid fish, Oreochromis niloticus, were raised from hatching in small groups consisting of a normal individual (the test fish) and either mutant conspecifics lacking the dorsal fin and thereby the ability to perform fin displays, or normal ones. Following a 63-day period of development in groups the test fish were confronted in their home tanks with an unfamiliar normal fish for 10 min. The fighting behaviour of the test fish was analyzed considering their previous group type (mutant or normal) and rank (alpha or beta). There was no difference between test fish in the rate and sequence of behaviour patterns used in fighting. However, test fish that had developed in mutant groups were rarely the first to bite in contests and had a longer latency to biting following the first bite of the stimulus fish than rest fish with normal experience. This finding is attributable to the form of aggressive behaviour experienced by the test fish during development but not to existing differences in the amount of aggression previously experienced, nor to previous rank, sex, or size relative to the stimulus fish. The results suggest that early experience influenced decision making by the test fish during the fight. The involvement of the fin displays and the possible mechanism of this influence are discussed.

Morphological, morphometric, and molecular characterization of Hepatozoon spp. (Apicomplexa, Hepatozoidae) from naturally infected Caudisona durissa terrifica (Serpentes, Viperidae)

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

Megaselia scalaris (Diptera : Phoridae) causing myiasis in Crotalus durissus terrificus (Serpentes : Viperidae) in Brazil

We describe a case of myiasis in Crotalus durissus terrificus (Laurenti) caused by Megaselia scalaris (Loew). The snake was Found in Anhembi, São Paulo, Brazil, with a lesion measuring 25 mm in diameter where the larvae of M. scalaris had penetrated the ribs. The opportunistic behavior of the larvae of M. scalaris is discussed.

In vitro effects of Crotalus durissus terrificus and Bothrops jararaca venoms on Giardia duodenalis trophozoites

Considering the snake venoms' pharmacological properties and chemotherapeutic potential as well as the need for new alternatives for Giardia infection treatment, the present study was carried out aiming to evaluate the in vitro effects of crude Crotalus durissus terrificus and Bothrops jararaca venoms on the growth and adherence of Giardia duodenalis trophozoites. Trophozoites (10(6)) were exposed to serial twofold dilutions of C. durissus terrificus and B. jararaca venoms that ranged from 3.125 to 200 mu g/ml and from 5 to 320 mu g/ml, respectively. The two venoms inhibited the growth of trophozoites, and the level of inhibition varied according to the assayed concentrations and incubation times. The highest reduction of parasite growth was observed with increasing concentrations of the venoms. No effect on parasite adherence was observed. Light microscope observations revealed changes of the pear-shape aspect of the cell and reduction of flagellar beating frequency in the great part of the trophozoites. This is the first attempt to evaluate the in vitro effects of snake venoms on Giardia trophozoites. The findings stress the need for more investigations and prompt us to perform further studies to identify active principles with antigiardial effect.

Prevalence of Hepatozoon spp. (Apicomplexa, Hepatozoidae) among recently captured Brazilian snakes

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

Helminths From an Introduced Species (Tupinambis merianae), and Two Endemic Species (Trachylepis atlantica and Amphisbaena ridleyi) From Fernando de Noronha Archipelago, Brazil

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

Reptilia, Squamata, Dipsadidae, Xenodontinae, Taeniophallus brevirostris (Peters, 1863): distribution extension and new state record.

Taeniophallus brevirostris is a dipsadid snake widely distributed in Amazon. Here we report a new Brazilian state record for the species, improving our knowledge of its geographic distribution. 0n 15 May of 2008, one female specimen was collected do Serra do Santo Expediot, Aripuana municipality, state of Mato Grosso, Brazil. This is the first record of this species for the state of Mato Grosso and extends its distribution ca. 300 kilometers from the nearest localities presented in literature.

Squamata, Elapidae, Micrurus surinamensis (Cuvier, 1817): new records and distribution map in the state of Mato Grosso, Brazil, with notes on diet and activity period.

We report six new records of M. surinamensis and present the map of distribution with known records for this species of semiaquatic coral snake in the state of Mato Grosso, Brazil.

Rabies transmitted by vampire bats to humans: An emerging zoonotic disease in Latin America?

Human rabies transmitted by vampire bats reached new heights in Latin America in 2005. A total of 55 human cases were reported in several outbreaks, 41 of them in the Amazon region of Brazil. Peru and Brazil had the highest number of reported cases from 1975 to 2006. In Peru, outbreaks involving more than 20 cases of bat-transmitted human rabies were reported during the 1980s and 1990s. During this period, a smaller number of cases were reported from outbreaks in Brazil. A comparison of data from field studies conducted in Brazil in 2005 with those from the previous decade suggests similar bat-bite situations at the local level. The objective of this study was to review the epidemiological situation and, on the basis of this information, discuss possible factors associated with the outbreaks. Prevention and control measures already recommended for dealing with this problem are also reviewed, and some further suggestions are provided.

Expression and processing of recombinant sarafotoxins precursor in Pichia pastoris

Sarafotoxins are peptides isolated from the Atractaspisw snake venom. with strong constrictor effect on cardiac and smooth muscle. They are structurally and functionally related to endothelins. The sarafotoxins precursor cDNA predicts an unusual structure 'rosary-type', with 12 successive similar stretches of sarafotoxin (SRTX) and spacer, in the present work, the recombinant precursor of SRTXs was sub-cloned and expressed in the yeast Pichia pastoris. and secreted to the culture medium, Characterization by SDS-PAGE, immunoblot, mass spectrometry and biological activity, suggests that intact precursor was expressed but processing into mature toxins also occurred. Furthermore, our results indicate that the correct proportion of sarafotoxin types as contained in the precursor, is obtained in the yeast culture medium. Contractile effects of the expressed toxins, on rat and Bothrops jararaca isolated aorta, were equivalent to 5 X 10(-10) M and 5 x 10(-11) M of sarafotoxin b, respectively. The enzymes responsible for the complete maturation of sarafotoxins precursor are still unknown. Our results strongly suggest that the yeast Pichia pastoris is able to perform such a maturation process. Thus, the yeast Pichia pastoris may offer an alternative to snake venom gland to tentatively identify the molecular process responsible for SRTXs release. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

EVIDENCE of A FAILED PREDATION ATTEMPT on A GUIANA DOLPHIN, Sotalia guianensis, BY A BULL SHARK, Carcharhinus leucas, IN BRAZILIAN WATERS.

Even though shark-cetacean interactions have been the subject of numerous studies worldwide, several ecological aspects such as competition, predation risk and co-evolution remain unclear. on February 16th, 2008, during a photo-identification survey to investigate population parameters of Guiana dolphins, Sotalia guianensis, in estuarine waters of Parana State (25[degree]S; 48[degree]W), Brazil, an adult dolphin was photographed without its dorsal fin. A detailed analysis of the healed area on the injured dolphin showed that the circular, crescent-shaped outlined wound was provoked by the bite of a bull shark, Carcharhinus leucas. Wound shape, prey-predator distributional patterns (sympatry) and feeding habits of the shark species here considered were indicative of the species' identity. The wound is likely to be the result of a failed predation attempt. Interactions between C. leucas and S. guianensis should be expected, since they are sympatric along almost all of their distribution range in the tropical and subtropical western South Atlantic. The presented observation adds S. guianensis to the list of cetacean species involved in interactions with large coastal predatory sharks.