Human plasma plasminogen internalization route in Plasmodium falciparum-infected erythrocytes.

BACKGROUND: The intra-erythrocytic development of the malaria parasite Plasmodium falciparum depends on the uptake of a number of essential nutrients from the host cell and blood plasma. It is widely recognized that the parasite imports low molecular weight solutes from the plasma and the consumption of these nutrients by P. falciparum has been extensively analysed. However, although it was already shown that the parasite also imports functional proteins from the vertebrate host, the internalization route through the different infected erythrocyte membranes has not yet been elucidated. In order to further understand the uptake mechanism, the study examined the trafficking of human plasminogen from the extracellular medium into P. falciparum-infected red blood cells. METHODS: Plasmodium falciparum clone 3D7 was cultured in standard HEPES-buffered RPMI 1640 medium supplemented with 0.5% AlbuMAX. Exogenous human plasminogen was added to the P. falciparum culture and the uptake of this protein by the parasites was analysed by electron microscopy and Western blotting. Immunoprecipitation and mass spectrometry were performed to investigate possible protein interactions that may assist plasminogen import into infected erythrocytes. The effect of pharmacological inhibitors of different cellular physiological processes in plasminogen uptake was also tested. RESULTS: It was observed that plasminogen was selectively internalized by P. falciparum-infected erythrocytes, with localization in plasma membrane erythrocyte and parasite's cytosol. The protein was not detected in parasitic food vacuole and haemoglobin-containing vesicles. Furthermore, in erythrocyte cytoplasm, plasminogen was associated with the parasite-derived membranous structures tubovesicular network (TVN) and Maurer's clefts. Several proteins were identified in immunoprecipitation assay and may be involved in the delivery of plasminogen across the P. falciparum multiple compartments. CONCLUSION: The findings here reported reveal new features regarding the acquisition of plasma proteins of the host by P. falciparum-infected erythrocytes, a mechanism that involves the exomembrane system, which is distinct from the haemoglobin uptake, clarifying a route that may be potentially targeted for inhibition studies.

Análise de contaminação por microorganismos em latas de cerveja comercializadas na cidade de Sorocaba-SP / Analysis of contamination by microorganisms in beer cans marketed in the city of Sorocaba -SP

Objetivo ­ Determinar a presença de microrganismos na lata de cerveja, coletando amostras de três diferentes grupos de comerciantes, divididos em: G1 ­ Vendedores ambulantes, G2 ­ Bares e G3 ­ Supermercados do município de Sorocaba/SP, totalizando 33 amostras com e sem selo de proteção. Métodos ­ Foram realizadas a inoculação de todas as amostras em meios de cultura apropriados, analisando o nível de crescimento de cada uma e utilizando das provas bioquímicas especificas para identificação do microrganismo. Resultados ­ Das 30 amostras, excluídas as 3 amostras controle, apenas 5 sem o selo de proteção foram positivas, sendo que em três delas houve crescimento de bactérias Gram negativas e em duas houve o crescimento de bactérias Gram positivas. Conclusão ­ Com os resultados obtidos, foi possível concluir que a utilização do selo de proteção e a higienização anterior ao consumo são eficazes para evitar a contaminação bacteriana, pois em nenhuma dessas amostras houve crescimento de microrganismos

Objective ­ To determine the presence of microorganisms in the beer can, collecting samples from three different groups of markets, divided into: G1 - Street vendors, G2 - Bars and G3 - Supermarkets in the city of Sorocaba / SP, totaling 33 samples with and without protective seal. Methods ­ All samples were inoculated in appropriate culture media, analyzing the growth level of each one and using the specific biochemical tests to identify the microorganism. Results ­ Of the 30 samples, excluding the 3 control samples, only 5 without the protective seal were positive, in three of them there was growth of Gram negative bacteria and in two there was growth of Gram positive bacteria. Conclusion ­ With the results obtained, it was possible to conclude that the use of the protective seal and the cleaning prior to consumption are effective to avoid bacterial contamination, since in none of these samples there was growth of microorganisms