The fluorescein diacetate-ethidium bromide (FDA-EB) fluorescence method, primarily used to determine viability of mammalian cells, was applied to several fungi species. Living fungi cells produced fluorochromasia, i.e., an intracellular accumulation of fluorescein which could be easily visualized as a green color under the U.V. microscope. Dead cells showed a red bright color due to ethidium bromide penetration. The FDA-EB test can be successfully employed to assay yeast and yeast like cells viability since a good correlation was observed between this assay and the colony count technique. The main advantages of FDA-EB test are its speed, high sensitivity and simplicity.

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One hundred samples of commercially available cows milk, collected in the state of São Paulo, from July 1979 to September 1981, were analysed to determine the levels of aflatoxins M1 and M2 by the method of the AOAC. This investigation was also undertaken in 50 samples of cows milk from two farms located in the Médio Vale do Paraiba, from animals which had ingested stored feed. Aflatoxin M1 was detected in only one sample of commercially available cows milk, while those from the farms were found to contain a minimum of 0.1 microgram/l and a maximum of 1.68 microgram/l.

The effectiveness of the fluorescent viability test (fluorescein diacetate-FDA and ethidium bromide-EB-solution) compared to the plaque counting test (Miles & Misra M & M) was performed on 10 samples of Cryptococcus neoformans cultivated in Sabouraud dextrose agar at 25 degrees C. The optimum incubation period of 50 minutes was determined. Growth curves of the fungal strains studied based on the mean cell number were drawn for both the FDA & EB and M & M methods. The statistical evaluation (Student's T test) of the average sum of the viable cell counts showed that the FDA-EB method is more sensitive than the M & M test for the studied species. The growth curves of the samples usually followed a homogeneous pattern comparable to other non-dimorphic fungi.

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Liver and kidney tissues and urine from calves chronically or acutely intoxicated by aflatoxin were surveyed to detect the presence of aflatoxins B1, M1 (AFB1, AFM1) and aflatoxicol (AFL). Aflatoxins B1, M1, and aflatoxicol were not found in the liver, kidney or urine from animals intoxicated by chronic forms. However in a calf that received a single dose of 0.8 mg of AFB1/kg of live weight and one submitted to a single dose of 1.8 mg of AFB1/kg of live weight detectable levels of aflatoxins occurred in tissues and urine.

Padronizou-se método de fluorescência (solução de diacetato de fluoresceína DF e brometo de etídio BE) para análise de viabilidade de células fúngicas, em 40 amostras de liquor, provenientes de casos comprovados de neurocriptococose. A utilização de solução aquosa de saponina a 0,3% eliminou fluorescências interferentes emitidas por hemácias e leucócitos. Após o processamento dos materiais biológicos, foram retiradas alíquotas de 0,1 ml das supensões obtidas e misturadas a volumes iguais da solução DF-BE preparada pouco antes do uso. O tempo de coloração ideal foi de 30 minutos, resultando perfeita diferenciação entre microrganismos viáveis (fluorescência verde) e não viáveis (fluorescência vermelha).

No abstract