Influência da aplicação de irradiação por feixe de elétrons na qualidade microbiológica de filés de corvina (Micropogonias furnieri) refrigerados / Influence of irradiation application for electron beam on the microbiological quality of chilled croaker (Micropogonias furnieri) fillets

A adequada manipulação do pescado desde sua captura até seu processamento tecnológico, além da manutenção das condições higiênico-sanitárias, o que inclui a qualidade da água utilizada na cadeia, influencia na carga microbiana inicial apresentada. A fim de retardar o processo de deterioração, diminuir as perdas e os riscos iminentes à saúde coletiva, como a propagação de agentes etiológicos de doenças alimentares, são empregados diferentes métodos de conservação. Os feixes de elétrons são utilizados em vários países e levam à destruição dos microrganismos por alterações em suas estruturas, as quais ocorrem pela remoção de elétrons de seus átomos. Objetivou-se, no presente trabalho, contribuir para a avaliação da eficiência da irradiação por feixe de elétrons na qualidade microbiológica de filés de corvina (M. furnieri) refrigerados, desembarcados no município de Niterói - RJ, Brasil. Foram realizadas contagem de bactérias heterotróficas aeróbias mesófilas, de bactérias heterotróficas aeróbias psicrotróficas e enumeração de Enterococcus spp. e, posteriormente, comparadas as amostras do grupo controle com as dos grupos irradiados a doses de 0,7 e 1,0kGy. Os peixes inteiros foram adquiridos no cais de Itaipu, filetados no mercado, embalados a vácuo e mantidos a ±4°C. Embora não tenha sido encontrada diferença estatisticamente significativa entre os três grupos (P>0,05) em nenhuma das análises, concluiu-se que o processamento utilizado foi eficaz na redução do crescimento das três bactérias pesquisadas no dia zero de ambos os grupos irradiados.

The proper handling of fish from capture to technological processing, as well as maintenance of sanitary conditions and the quality of water, can influence the initial microbial load presented. In order to slow down the deterioration process, the reduction of losses and eminent risk to public health as the spread of etiological agents of foodborne illness are different methods used for storage. Electron beams are used in several countries and lead to the destruction of microorganisms by changes in their structures, which occur by removing electrons from their atoms. The objective in the present study contributes to the evaluation of electron beam irradiation efficiency in microbiological quality of chilled croaker fillets (M. furnieri), landed in Niterói - RJ, Brazil. Were performed Bacteria Count Heterotrophic aerobic mesophilic, psychrotrophic bacteria Heterotrophic Aerobic and enumeration of Enterococcus spp. and subsequently compared to the control group of samples with the groups irradiated at doses of 0.7 and 1.0kGy. Whole fish were purchased from the Itaipu pier, threaded on the market, vacuum packed and kept at ±4°C. Although there was no statistically significant difference among the three groups (P>0.05) in any of the analyzes, it was concluded that the application of this technology was effective in reducing the growth of the three bacteria surveyed on day zero of both irradiated groups.

An integrated model for cellular analysis

We present the MOlecular NETwork (MONET) ontology as a model to integrate data from different networks that govern cell function. To achieve this, different existing ontologies were analyzed and an integrated ontology was built in a way to make it possible to share and reuse knowledge, support interoperability between systems, and also allow the formulation of hypotheses through inferences. By studying the cell as an entity of a myriad of elements and networks of interactions, we aim to offer a means to understand the large-scale characteristics responsible for the behavior of the cell and to enable new biological insights.

Activity of synaptosomal ATP diphosphohydrolase from hippocampus of rats tolerant to forebrain ischemia

Cerebral ischemia causes cell death of vulnerable neurons in mammalian brain. Wistar adult rats (male and female, weighing 180-280 g) were submitted to 2 min, 10 min, or to 2 and 10 min (separated by a 24-h interval) of transient forebrain ischemia by the four-vessel occlusion method. Animals subjected to the longer ischemic episodes had massive necrosis of pyramidal CA1 cells of the hippocampus, while animals receiving double ischemia (2 + 10 min) showed neuronal tolerance to the ischemic insult. ATP-diphosphohydrolase activity from hippocampal synaptosomes was assayed in these three groups (N = 6 animals/group) under two conditions: no reperfusion and 5-min of reperfusion. The control values for ATPase and ADPase activities were 144.7 +/- 18.8 and 60.6 +/- 5.24 nmol Pi min-1 mg protein-1, respectively. The 10-min group without reperfusion showed an enhancement of approximately 20 for ATPase and ADPase activities. In reperfused rats, only the 2-min group had a 20 increase in both enzymatic activities. We suggest that modulation of ATP-diphosphohydrolase activity might be involved in molecular events that follow both ischemia and reperfusion.

Inhibitory effect of cadmium acetate on synaptosomal ATP diphosphohydrolase (EC 3.6.1.5; apyrase) from adult rat cerebral cortex

ATP diphosphohydrolase (EC 3.6.1.5; apyrase) is an enzyme that can promote ATP and ADP hydrolysis to AMP plus inorganic phosphate and depends on divalent cations such as Ca2+ or Mg2+. In previous papers we described this enzyme in the synaptosomal fraction from the central and peripheral nervous system. The present report examines whether cadmium acetate could affect the in vitro activity of the enzyme in the synaptosomal fraction from the cerebral cortex of adult male Wistar rats. Cadmium (Cd2+), a heavy metal with neurotoxic effects, inhibited the enzyme in a concentration-dependent manner. All concentrations tested (0.05-1.0 mM) significantly inhibited the hydrolysis of both substrates (ATP and ADP), with the exception of 0.05 mM on ATP hydrolysis. The kinetic data indicate a noncompetitive inhibition between the cations Cd2+ and Ca2+.