Aerobic and anaerobic degradation of tannic acid on water samples from Monjolinho reservoir (Säo Paulo, SP, Brazil)

In order to describe the transformations of tannic acid during its degradation (under aerobic and anaerobic conditions) incubations were performed. To evaluate the oxygen consumption, the tannic acid was added to 1 L of water sample from Monjolinho's reservoir (22º00'S and 47º54'W); these solutions were aerated and the dissolved oxygen was monitored for 16 days, the anaerobic process was avoided. For the anaerobic and aerobic degradation, the dissolved organic carbon and the acid tannic concentrations were estimated on the samples days. The results were fitted to first-order kinetic model, being possible to verify that during the 16 days the oxygen uptake was 3.6 mg.L-1, the deoxygenation rate (kD)of this process was 0.39 day-1. The degradation coefficients were calculated through the decay of the tannic acid and organic carbon concentrations. In the aerobic process, the global decay coefficient (kG) was 0.36 day-1 and in the anaerobic 0.28 day-1. Overall, the obtained degradation coefficients suggest that the bacterioplankton of the Monjolinho's reservoir possess a high capacity of polyphenols degradation

Differential effect of culture epimastigotes and blood-form Trypamastigotes on normal mouse splenocyte responsiveness to mitogens

Tripomastigotas de sangue da cepa Y de T. cruzi mostraram uma forte inibiçäo da resposta de transformaçäo blástica a mitógenos de células T e B, nas estirpes C3H/He, C57BL/6 e BALB/cJ de camundongos, enquanto epimastigotas de cultura da cepa Y mantidos em meio que permite o crescimento dos parasitas a 26-, 30-, 34- e 37-C mostraram um forte efeito estimulante, que foi inclusive maior que o efeito dos mitógenos isolados. Os efeitos de inibiçäo e de estimulaçäo foram dependentes da dose. O efeito estimulante dos epimastigotas também foi dependente da temperatura, encontrando-se maiores índices de estimulaçäo à medida que a temperatura da cultura dos parasitas foi aumentada. Parasitas vivos, metabolicamente ativos, parecem ser necessários para a obtençäo de uma maior estimulaçäo dos linfócitos, o que sugere um papel potencial dos metabólitos segregados como ativadores policlonais dos linfócitos dos camundongos