Análise fitoquímica e avaliação das atividades anti-inflamatória, antipeçonhenta e citotóxica de extratos aquosos de Aspidosperma pyrifolium e Ipomoea asarifolia

Envenomation caused by venomous animals, mainly scorpions and snakes, are a serious matter of public health. Tityus serrulatus is considered the most venomous scorpion in South America because of the high level of toxicity of its venom. It is responsible for causing serious accidents, mainly with kids. The species Bothrops jararaca is a serpent that has in its venom a complex mixture of enzyme, peptides and other molecules. The toxins of the venom of B. jararaca induce local and systemic inflammatory responses. The treatment chosen to serious cases of envenomation is the intravenous administration of the specific antivenom. However, the treatment is not always accessible to those residents in rural areas, so that they use medicinal plant extracts as the treatment. In this context, aqueous extracts, fractions and isolated compounds of Aspidosperma pyrifolium (pereiro) and Ipomoea asarifolia (salsa, salsa-brava), used in popular medicine, were studied in this research to evaluate the anti-inflammatory activity in the peritonitis models induced by carrageenan and peritonitis induced by the venom of the T. serrulatus (VTs), and in the local oedema model and inflammatory infiltrate induced by the venom of the B. jararaca, administrated intravenously. The results of the assays of cytotoxicity, using the MTT, showed that the aqueous extracts from the plant species presented low toxicity to the cells that came from the fibroblast of the mouse embryo (3T3).The chemical analysis of the extracts by High Performance Liquid Chromatography revealed the presence of the rutin flavonoid, in A. pyrifoliu, and rutin, clorogenic acid and caffeic acid, in I. asarifolia. Concerning the pharmacological evaluation, the results showed that the pre-treatment using aqueous extracts and fractions reduced the total leukocyte migration to the abdominal cavity in the peritonitis model caused by the carrageenan and in the peritonitis model induced by the T. serulatus venom. Yet, these groups presented anti-oedematous activity, in the local oedema model caused by the venom of the B. jararaca, and reduced the inflammatory infiltrate to the muscle. The serum (anti-arachnid and anti-bothropic) specific to each venom acted inhibiting the inflammatory action of the venoms and were used as control. The compounds identified in the extracts were also tested and, similar to the plant extracts, showed meaningful anti-inflammatory effects, in the tested doses. Thus, these results are indicating the potential anti-inflammatory activity of the plants studied. This is the first research that evaluated the possible biological effects of the A. pyrifolium and I. asarifolia, showing the biological potential that these species have.

Influência dos odores de gato e de cobra no comportamento defensivo e expressão de fos do sistema hipotalâmico de defesa de camundongo

Studies using neuronal tract-tracer in rat have shown that the anterior hypothalamic nucleus, dorsomedial division of the ventromedial nucleus of the hypothalamus and dorsal premammillary nucleus are highly connected. When the rat is exposed to predator or its odor these nuclei have shown a expression of Fos and their lesion reduces defensive behavior against predator. This set of nuclei was named the Hypothalamic Defense System. However, little is known about the response of this system to the odor of different predators or its role in mice. In this work, we exposed Swiss mice to two different predators odor (cat and snake) to verify the Fos expression in the Hypothalamic Defense System, as well as the defensive behaviors displayed. The analysis showed that the mice exposure to cat odor had an increased expression of Fos protein compared to control, while those exposed to snake odor showed no rise in Fos expression, which was corroborated by the behavioral data. Our results indicate that this distinct circuit in mice seems to act differentially to odorous stimuli of different predators, causing distinct behavioral responses of mice and that the odor of snake seems not to be perceived by Swiss mice as a threatening stimulus.

Représentations analytiques des objets géométriques et contours actifs en imagerie

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Représentations analytiques des objets géométriques et contours actifs en imagerie

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Símbolos axiales en la poesía de José Ángel Valente

La poesía de José Ángel Valente posee una inusual densidad simbólica favorecida por la doble aspiración de abarcar tanto el extremo más grávido y material de la creación del autor, como aquel otro más etéreo y espiritual. Como componentes esenciales de esta búsqueda, podemos observar diversas imágenes (árbol, mandorla, hombre, cruz, etc.) que actuarán a modo de ejes simbólicos de su obra, ejes en torno a los cuales gira su universo poético. El estudio de los diferentes símbolos axiales, así como de otra serie de imágenes entendidas como proyecciones de aquéllos (laberinto, sierpe o nube), constituye el propósito del presente trabajo, tarea en la que relacionaremos cuanto vayamos descifrando con el sentido último de la poesía de José Ángel Valente.

De Irlanda a Iberia: notas para a tradución de Eiléan Ní Chuilleanáin do inglés ao galego

La cuestión del género fue trabajada dentro de los estudios de traducción de diversas formas, incluyendo la asignación de género en la lengua meta, la traducción de lenguaje marcado de género y la traducción feminista. En este trabajo se estudia el uso o ausencia de marcas de género y de la praeterio a la hora de afrontar una traducción al gallego de la autora irlandesa Eiléan Ní Chuillanáin, feminista y nacionalista. Ambas situaciones se reflejan conscientemente en sus poemas de manera significativa. A través de ejemplos prácticos seleccionados, se reflexiona sobre la necesidad de tener en cuenta que la traslación de sus textos a una lengua que obligatoriamente establece elecciones lingüísticas entre el femenino y el masculino, debe hacerse respetando el sentido de la autora. Esto supone, para quien traduzca, compartir la perspectiva feminista y nacional de la autora familiarizándose con el marco y condicionantes de su obra poética.

Biologia reprodutiva e ecologia trófica de Thamnodynastes hypoconia (Serpentes: Dipsadidae) em ambientes úmidos subtemperados do extremo sul brasileiro

O estudo teve como objetivo descrever a biologia reprodutiva e a dieta de populações de Thamnodynastes hypoconia em ambientes úmidos subtemperados do extremo sul brasileiro. Para avaliação da reprodução foram feitas análises macroscópicas das gônadas. Para avaliação da ecologia alimentar foram empregadas análises de conteúdo estomacal e de isótopos estáveis (δ13C e δ15N). Os machos apresentaram maior comprimento rostro-cloacal que as fêmeas e atingiram a maturidade sexual com menor tamanho corporal. O ciclo reprodutivo das fêmeas foi sazonal, com vitelogênese secundária ocorrendo entre o inverno e a primavera. Os machos apresentaram ciclo contínuo. Aparentemente a cópula ocorre entre o final da primavera e o início do verão, quando foram detectados embriões nas fêmeas e a parturição ocorreu no verão. Não houve relação entre o tamanho da ninhada e o tamanho da fêmea, e a frequência reprodutiva de 40% foi considerada relativamente baixa. Todavia, por ser uma espécie dominante em banhados subtemperados do extremo sul do Brasil sua estratégia reprodutiva parece ser eficiente. Dessa forma, o ciclo contínuo dos machos, bem como a viviparidade possam potencializar o deslocamento do pico reprodutivo da população de modo a ajustar-se de acordo com os picos de temperatura do ambiente. A análise de conteúdo estomacal mostrou uma dieta predominantemente anurófaga, exceto por um único lagarto. Hylidae foi a família mais representativa, com predomínio de Hypsiboas pulchellus, seguida de Leptodactylidae, onde Leptodactylus latrans teve maior importância. As análises de isótopos estáveis corroboraram a importância dessas espécies na alimentação da serpente. Apesar de ser uma serpente terrestre, T. hypoconia apresentou assinatura isotópica mais próxima das fontes primárias oriundas do ambiente aquático, o que indica a importância das áreas alagáveis para a subsistência de organismos terrestres de habitats adjacentes.

Biogeographical distribution of Rimicaris exoculata resident gut epibiont communities along the Mid-Atlantic Ridge hydrothermal vent sites

Rimicaris exoculata is a deep-sea hydrothermal vent shrimp which enlarged gill chamber houses a complex trophic epibiotic community. Its gut harbours an autochthonous and distinct microbial community. This species dominates hydrothermal ecosystems megafauna along the Mid-Atlantic Ridge, regardless of contrasted geochemical conditions prevailing in them. Here, the resident gut epibiont community at four contrasted hydrothermal vent sites (Rainbow/TAG/Logatchev/Ashadze) was analysed and compiled with previous data to evaluate the possible influence of site location, using 16S rRNA surveys and microscopic observations (TEM, SEM and FISH analyses). Filamentous epibionts inserted between the epithelial cells microvilli were observed on all examined samples. Results confirmed resident gut community affiliation to Deferribacteres, Mollicutes, Epsilonproteobacteria and to a lesser extent Gammaproteobacteria lineages. Still a single Deferribacteres phylotype was retrieved at all sites. Four Mollicutes-related OTUs were distinguished, one being only identified on Rainbow specimens. The topology of ribotypes median-joining networks illustrated a community diversification possibly following demographic expansions, suggesting a more ancient evolutionary history and/or a larger effective population size at Rainbow. Finally, the gill chamber community distribution was also analysed through ribotypes networks based on sequences from R. exoculata collected at Rainbow/Snake Pit/TAG/Logatchev/Ashadze sites. Results allow refining hypotheses on the epibiont role and transmission pathways.

Molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon Thermococcus barophilus

The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response. Introduction

Characterization of a new platelet aggregating factor from crotoxin Crotalus durissus cascavella venom

In this article we investigated the platelet aggregating activity of whole crotoxin and its subunits isolated from Crotalus durissus cascavella venom. During the purification protocols of the venom, using HPLC molecular exclusion, we detected the presence of two different serine protease activities in the gyroxin fraction, and another in the crotoxin fraction, which induced strong and irreversible platelet aggregation, in addition to blood coagulation. From crotoxin, we isolated PLA(2), crotapotin (both fractions corresponding approximately 85% of whole crotoxin) and another minor fraction (F20) that exhibited serine protease activity. After a new fractionation on reverse phase HPLC chromatography, we obtained three other fractions named as F201, F202 and F203. F202 was obtained with high degree of molecular homogeneity with molecular mass of approximately 28 kDa and a high content of acidic amino residues, such as aspartic acid and glutamic acid. Other important amino acids were histidine, cysteine and lysine. This protein exhibited a high specificity for BApNA, a Michaelis-Menten behavior with Vmax estimated in 5.64 mu M/min and a Km value of 0.58 mM for this substrate. In this work, we investigated the ability of F202 to degrade fibrinogen and observed alpha and beta chain cleavage. Enzymatic as well as the platelet aggregation activities were strongly inhibited when incubated with TLCK and PMSF, specific inhibitors of serine protease. Also, F202 induced platelet aggregation in washed and platelet-rich plasma, and in both cases, TLCK inhibited its activity. The N-terminal amino acid sequence of F202 presented a high amino acid sequence homology with other thrombin-like proteins, but it was significantly different from gyroxin. These results showed that crotoxin is a highly heterogeneous protein composed of PLA(2), thrombin-like and other fractions that might explain the diversity of physiological and pharmacological activities of this protein.

Biological and structural characterization of a new PLA(2) from the Crotalus durissus collilineatus venom

In the present article we report on the biological characterization and amino acid sequence of a new basic Phospholipases A(2) (PLA(2)) isolated from the Crotalus durissus collilineatus venom (Cdcolli F6), which showed the presence of 122 amino acid residues with a pI value of 8.3, molecular mass of 14 kDa and revealed an amino acid sequence identity of 80% with crotalic PLA(2)s such as Mojave B, Cdt F15, and CROATOX. This homology, however, dropped to 50% if compared to other sources of PLA(2)s such as from the Bothrops snake venom. Also, this PLA(2) induced myonecrosis, although this effect was lower than that of BthTx-I or whole crotoxin and it was able to induce a strong blockage effect on the chick biventer neuromuscular preparation, independently of the presence of the acid subunid (crotapotin). The neurotoxic effect was strongly reduced by pre-incubation with heparin or with anhydrous acetic acid and rho-BPB showed a similar reduction. The rho-BPB did not reduce significantly the myotoxic activity induced by the PLA(2), but the anhydrous acetic acid treatment and the pre-incu-bation of PLA(2) with heparin reduced significantly its effects. This protein showed a strong antimicrobial activity against Xanthomonas axonopodis passiflorae (Gram-negative), which was drastically reduced by incubation of this PLA(2) with rho-BPB, but this effect was marginally reduced after treatment with anhydrous acetic acid. Our findings here allow to speculate that basic amino acid residues on the C-terminal and molecular regions near catalytic site regions such as Calcium binding loop or rho-wing region may be involved in the binding of this PLA(2) to the molecular receptor to induce the neurotoxic effect. The bactericidal effect, however, was completely dependent on the enzymatic activity of this protein.

Purification and biological effects of a C-type lectin isolated from Bothrops moojeni

Snake venom proteins from the C-type lectin family have very distinct biological activities despite their highly conserved primary structure, which is homologous to the carbohydrate recognition region of true C-type lectins. We purified a lectin-like protein (BmLec) from Bothrops moojeni venom and investigated its effect on platelet aggregation, insulin secretion, antibacterial activity, and isolated kidney cells. The BmLec was purified using two chromatographic steps: affinity chromatography and reverse phase high performance liquid chromatography (HPLC). BmLec showed a dose-dependent platelet aggregation and significantly decreased the bacterial growth rate in approximately 15%. During scanning electron microscopy, the profile of Xanthomonas axonopodis pv. passiflorae treated with lectin disclosed a high vesiculation and membrane rupture. BmLec induced a strong and significant increase in insulin secretion at 2.8 and 16.7 mM glucose concentrations, and this effect was seen in the presence of EGTA in both experiments. BmLec (10 mu g/mL) increased the perfusion pressure, renal vascular resistance and urinary flow. The glomerular filtration rate and percentages of sodium, potassium and chloride tubular transport were reduced at 60 minutes of perfusion. Renal alterations caused by BmLec were completely inhibited by indomethacin in all evaluated parameters. In conclusion, the C-type lectin isolated from Bothrops moojeni affected platelet aggregation, insulin secretion, antibacterial activity and isolated kidney function.

Renal and vascular effects of the natriuretic peptide isolated from Crotalus durissus cascavella venom

Crotalus durissus cascavella is a snake that is usually found in the scrublands of northeast Brazil. The components of its venom may have effects on the vascular and renal systems. Recently, a new bradykinin inhibitory peptide has been identified in the venom of the Crotalinae family. The aim of the present study was to investigate the renal and vascular effects of the natriuretic peptide isolated from the venom of Crotalus durissus cascavella (NP2_Casca). The chromatographic profile showed the fractionation of substances identified as convulxin, gyroxin, crotoxin and crotamine, as well as fractions V and VI. The electrophoretic profile of fraction V consisted of several bands ranging from approximately 6 kDa to 13 kDa, while fraction VI showed only two main electrophoretic bands with molecular weights of approximately 6 and 14 kDa. Reverse-phase chromatography showed that NP2_Casca corresponds to about 18% of fraction VI and that this fraction is the main natriuretic peptide. NP2_Casca was compared to other natriuretic peptides from other sources of snake venom. All amino acid sequences that were compared showed a consensus region of XGCFGX, XLDRIX and XSGLGCX. The group treated with NP2-Casca showed an increase in perfusion pressure, renal vascular resistance, urinary flow and glomerular filtration rate. The percent of total and proximal tubular transport of sodium was reduced significantly after administration of the peptide. The mean arterial pressure showed a dose-dependent decrease after infusion of NP2_Casca, and an increase in nitrite production. In the aortic ring assay, NP2_Casca caused a relaxant effect in endothelium-intact thoracic aortic rings precontracted with phenylephrine in the presence and absence of isatin. NP2_Casca failed to relax the aortic rings precontracted with an isosmotic potassium Krebs-Henseleit solution. In conclusion, the natriuretic peptide isolated from Crotalus durissus cascavella venom produced renal and vascular effects. NP2_Casca reduced total and proximal sodium tubular transport, leading to an increase in sodium excretion, thereby demonstrating a diuretic action. A hypotensive effect was displayed in an arterial pressure assay, with an increase in nitrite production, suggesting a possible vasoactive action. (C) 2008 Elsevier Ltd. All rights reserved.