Typing and patterns of cellular morphological alterations in Cryptococcus neoformans and Cryptococcus gattii isolates exposed to a panel of killer yeasts.
Cryptococcus neoformans and Cryptococcus gattii are encapsulated basidiomycetous yeasts that cause meningoencephalitis. The action of killer yeasts on the growth of one hundred genotypically characterized C. neoformans var. neoformans, C. neoformans var. grubii, and C. gattii clinical and environmental isolates was evaluated. Killer studies were performed on yeast malt-methylene blue (YM-MB) agar Petri dishes, and a dendrogram was obtained based on a quantitative data matrix using the diameter of the inhibition halo. The cellular morphological characteristics of dead cells within the halo were observed by means of optical and scanning electron microscopy. There was no formation of pores on the cell surface of the sensitive cells in contact with the toxins, at least for C. neoformans. The sensitivity patterns of clinical and environmental isolates to the killer toxins demonstrated that there is correlation between killer sensitivity of Cryptococcus species or varieties and some of the killer strains. In this case, the isolates were discriminated using the killer sensitivity patterns, and this could be used as a complementary tool to PCR-fingerprinting in epidemiological studies.
Fuentefria
Alexandre M
AM
Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul, RS, Brazil.
Faganello
Josiane
J
Pazzini
Fabiano
F
Schrank
Augusto
A
Valente
Patrícia
P
Vainstein
Marilene
M
D000898:Antibiosis; D003454:Cryptococcus / Q000145:classification* / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure*; D003455:Cryptococcus neoformans / Q000145:classification* / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure*; D006801:Humans; D055646:Killer Factors, Yeast; D008855:Microscopy, Electron, Scanning; D016533:Mycological Typing Techniques; D009183:Mycotoxins / Q000378:metabolism / Q000494:pharmacology*; D004718:Saccharomycetales / Q000254:growth & development* / Q000378:metabolism; D014250:Trichosporon / Q000254:growth & development* / Q000378:metabolism
D055646:Killer Factors, Yeast; D009183:Mycotoxins