Maria de Fátima Costa Pires

EXPERIMENTAL MODEL OF CANDIDA ALBICANS (SEROTYPES A AND B) ADHERENCE IN VITRO

The adherence of Candida albicans is considered an important virulence factor since it determines the colonization of the yeast in various regions of the host, being the initial cause of the infection. In this work we studied the adherence of C. albicans (serotypes A and B) to HeLa and Vero cells after culture for 18 h and 30 h in chemically defined medium (YNB) plus carbohydrate sources such as glucose, sucrose, maltose, galactose and mannose (500 mM). Each assay was performed in triplicate. The best results were obtained with the medium containing glucose. The adherence was greatest in 18 h cultures at 37oC and at 1 h contact time. The interaction of yeast cells with the host cells was studied by scanning microscopy.

Time course of virus-like particles (VLPs) double-stranded rna accumulation in toxigenic and non-toxigenic strains of Aspergillus flavus

Two strains of Aspergillus flavus, non-toxigenic NRRL 6550 and toxigenic NRRL 5940, were studied over a period of 44 days, in order to detect the presence of virus-like particles (VLPs) by means of electron microscopy (EM) and nucleic acids electrophoresis. Only the toxigenic strain contained VLPs, presenting three-segmented dsRNA. An increase in VLPs number was observed during the exponential phase of fungal growth, up to day 12 of culture; after this, higher levels of aflatoxin production in toxigenic NRRL 5940 mycelia occurred in parallel with decreased VLPs replication.