Summary. The survival and stability of morphological traits of 33 Sporothrix schenckii strains were evaluated. Strain subcultures were maintained under mineral oil for different periods of time lasting as long as 41 years, or in sterile distilled water for as long as 23 years. Of the 33 strains preserved under mineral oil, 28 (85%) maintained viability and unchanged macro‐ and microscopic characteristics. All of the 4 strains maintained in distilled water also remained viable, with no morphological changes. The results confirm the efficiency of the methods used to preserve strains of the pathogenous and anamorphous fungus Sp. schenckii, especially in laboratories of limited resources. Zusammenfassung. Es wurden Überlebens‐rate und Stabilität morphologischer Merkmale von 33 Sporothrix schenckiiStämmen geprüft. Sub‐kulturen wurden über unterschiedliche Zeiträume aufbewahrt: Bis zu 41 Jahren unter Mineralol und bis zu 23 Jahren in Aqua dest. Von den 33 unter Mineralöl aufbewahrten Stämmen blieben bi 28 (85%) Vermehrungsfähigkeit sowie makroskopisch‐ und mikroskopisch‐morphologische Merkmale unverändert erhalten. Alle vier in Aqua dest. aufbewahrten Stämme blieben ebenso morphologisch unverändert und vermehrungsfähig. Diese Ergebnisse bestätigen die Wirksamkeit beider Aufbewahrungsmethoden für die pathogene anamorphe Pilzart Sp. schenckii, insbesondere in Laboratorien mit beschränkten Ressourcen.

We evaluated the survival and the morphological alteration of 70 strains of Paracoccidioides brasiliensis maintained in the Fungal Culture Collection of Institute Oswaldo Cruz and initially preserved by successive subculturing and later under mineral oil at room temperature from 1923 to 1992. Of the 70 strains preserved under mineral oil, 18 (26%) continued to be viable. The mycelia of the 18 viable strains and the mycelia of four representatives of the non-viable strains presented transitional micromorphology under mineral oil. Macroscopy and microscopy of the first subcultures of five of the seven strains, taken as random samples from the 18 viable strains and plated onto peptone-yeast extract-glucose agar, glucose-glycine-yeast extract agar and brain-heart infusion agar media at room temperature, revealed that all samples appeared to be in a transition phase (Y<-->M). These five strains were unable to grow and complete thermal dimorphism at a temperature of 37 degrees C. Only two strains were able to complete the entire dimorphic process. The period of preservation of these strains under oil was relatively short, i.e. 9 and 10 years. The results demonstrate that less widely spaced subculturing and more appropriate culture and environmental conditions are needed to preserve P. brasiliensis strains under oil.

The growth and viability of two Paracoccidioides brasiliensis strains were evaluated in PYG and MMcM media containing no boric acid. The two P. brasiliensis strains exhibited a similar growth pattern in PYG medium, which was considered to be good compared with the growth curves in defined MMcM medium without boric acid. Calculation of cell generation time in the media studied demonstrated that the cells had greater difficulty in forming new generations in MMcM medium containing no boric acid. The present data confirm the literature view that PYG medium is the most complete in terms of nutritive substances for the growth and development of P. brasiliensis.

The presence and localization of storage polysaccharides and of polysaccharides as cell structure constituents of Paracoccidioides brasiliensis yeast-like cells and protoplasts were studied using the periodic acid-thiocarbohydrazide-silver proteinate (PATAg) technique. Yeast-like cells presented glycogen particles in the form of rosettes, which were mostly concentrated in regions of the cytoplasm. Cells in the budding process presented small amounts of glycogen in their matrix. The intracellular membranes and the attachment of the mother cell to the bud were clearly labelled by silver, demonstrating a large amount of glyco-conjugates. The protoplasts presented a small amount of glycogen in their cytoplasm, a reduction probably due to the enzymatic treatment to which the cells were submitted.