332 resultados para Virulência


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The objective of this research was to evaluate de reaction of leaves and pods of five cultivars of bean (Phaseolus vulgaris L.) plants to twenty strains of Xanthomonas campestris pv. phaseoli. The strains were inoculated onto leaves in a greenhouse, and onto pods in a growth chamber. The results obtained were analyzed and the strains classified into three groups: low, medium, and high virulence. Most of the strains showed high virulence on leaves of Carioca and Rio Negro cultivars, as opposed to only low to medium virulence on leaves of IAPAR 14, IAPAR 16, and G. N. Nebraska # 1 sel. 27 cultivars. There were, however, individual strains powerful enough to overcome the leaf resistance of IAPAR 14, IAPAR 16, and G. N. Nebraska # 1 sel. 27. With regard to pods, most strains showed high virulence on all bean cultivars, with exception of IAPAR 14 where virulence was at medium level. A correlation between leaf and pod symptoms was found to exist in Carioca, Rio Negro, and IAPAR 14 cultivars. No such correlation was observed in IAPAR 16 and G. N. Nebraska # 1 sel. 27. Comparing strains producing melanine in vitro with those not producing this pigment, no difference was observed with regard to virulence.

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Brucellosis remains an economic problem in animals and public health. Worldwide ovine brucellosis caused by Brucella ovis is considered a major cause of infertility in sheep. The factors responsible for persistence of the agent are not known, as well as the mechanisms involved in immune defense and possibly the persistence of the agent. Brucella spp. induces moderate inflammatory response. The nature of the intracellular agent stimulates immune response of the type 1 helper T lymphocytes. Studies of the pathogenesis of ovine brucellosis are scarce. Recent developments have shown that the inflammatory response induced by moderate brucelas represent probably the result of an attempt to escape the immune response and suppression of host immune response. Were reviewed by the mechanisms described by brucelas and Brucella ovis for penetration into the host, escape of the immune response and the immune response generated by the infection.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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

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Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR