Evaluation of phenotypic and genotypic alterations induced by long periods of subculturing of Cryptococcus neoformans strains.
Cryptococcus neoformans is an encapsulated fungal organism that can cause disease in apparently immunocompetent, as well as immunocompromised, hosts. Since 1930, successive subculture has been used to preserve C. neoformans isolates in our Fungus Collection. In the 1970s, some of these Fungus Collection samples were selected to be subjected to a different methods of maintenance--that of lyophilized. Our objective was to analyze C. neoformans isolates in order to make a comparative evaluation between these two methods of preservation. The overall aim of this study was to qualify the preservation technique used in our mycology laboratory since the technique used might affect the survival, stability and purity of the primary isolates in culture. The samples were analyzed using classical mycology methods and using the randomly amplified polymorphic DNA technique In the analysis of phenotypes and genotypes, the typical characteristics of C. neoformans were found to differ in relation to the different methods of preservation employed. The aim of this study was to demonstrate the importance of selecting the appropriate method of preservation for fungus collections. This selection can affect the survival and purity of the cultures, and preserve the stability of their physiological, biochemical, and genetic characteristics.
Cavalcante
Sonia Cristina
SC
Laboratório de Micologia Médica, Instituto de Medicina Tropical de São Paulo, Brasil. soniamicologia@yahoo.com
Freitas
Roseli Santos
RS
Vidal
Mônica Scarpelli Martinelli
MS
Dantas
Kátia Cristina
KC
Levi
José Eduardo
JE
Martins
José Eduardo Costa
JE
D003455:Cryptococcus neoformans / Q000235:genetics* / Q000502:physiology; D004271:DNA, Fungal / Q000032:analysis*; D005612:Freeze Drying; D005838:Genotype; D006801:Humans; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011309:Preservation, Biological / Q000379:methods*; D019105:Random Amplified Polymorphic DNA Technique; D013997:Time Factors
D004271:DNA, Fungal