Mating Types and Optimum Culture Conditions for Sexual State Formation of Fusarium fujikuroi Isolates

Twenty-five isolates of Fusarium fujikuroi acquired from rice seeds and rice plants evidencing symptoms of Bakanae disease were evaluated to determine their mating types and characterize the formation of their sexual state. The mating types of the isolates were evaluated via multiplex PCR with the diagnostic primers of the mating-type (MAT) region: GFmat1a, GFmat1b, GFmat2c, and GFmat2d. Among the 25 isolates, 11 were identified as MAT-1 (male), and 14 as MAT-2 (female). Four MAT-1 isolates and three MAT-2 isolates were mated and cultured to evaluate the optimal culture conditions for the production of their sexual states. Among four tested media, 10% V8 juice agar proved optimal for the perithecial production of the isolates. The isolates also generated the largest numbers of perithecia when incubated at 23degrees C in alternating cycles of 12 hr fluorescent light and NUV fluorescent light and 12 hr darkness.

Molecular characterization of environmental Cryptococcus neoformans isolated in Vitoria, ES, Brazil / Caracterização molecular de cepas ambientais de Cryptococcus neoformans isoladas em Vitória, ES, Brasil

Cryptococcus neoformans is the major cause of fungal meningitis, a potentially lethal mycosis. Bird excreta can be considered a significant environmental reservoir of this species in urban areas, thirty-three samples of pigeon excreta were collected within the city of Vitoria, Brazil. Cryptococcus neoformans was isolated and identified using standard biochemical assays in ten samples. PCR amplification with primer M13 and orotidine monophosphate pyrophosphorylase (URA5) gene-restriction fragment length polymorphism (RFLP) analysis discerned serotypes and genotypes within this species. All isolates were serotype A (C. neoformans var. grubii) and genotype VNI. The two alternative alleles a and α at the mating type locus were determined by PCR amplification and mating assays performed on V8 medium. All isolates were MAT α mating type but only 50 percent were able to mate in vitro with the opposite mating type MAT a tester strains (JEC20, KN99a and Bt63). This study adds information on the ecology and molecular characterization of C. neoformans in the Southeast region of Brazil.

O "complexo Cryptococcus neoformans" é constituído por C. neoformans var. neoformans, C. neoformans var. grubii, e C. gattii. Trinta por cento de amostras de excrementos de pombos coletados dentro da cidade de Vitória, Brasil, foram positivas para Cryptococcus neoformans, espécie identificada por testes bioquímicos convencionais. Amplificação por PCR com primer M13 e análise por orotidine monophosphate pyrophosphorylase (URA5) gene-"restriction fragment length polymorphism" (RFLP) distinguiram sorotipos e genotipos dentro desta espécie. Todos os isolados ambientais foram sorotipo A (C. neoformans var. grubii) e genotipo VNI. Os dois alelos alternativos a e α do locus "mating type" foram determinados por PCR e por testes de "mating" em meio V8. Todos os isolados foram "mating type" tipo MAT α mas somente 50 por cento foram capazes de conjugar in vitro com cepas MAT a, de "mating type" oposto (JEC20, KN99a e Bt63). Este estudo adiciona informações sobre a ecologia e caracterização molecular de cepas ambientais de C. neoformans, isoladas na região sudeste do Brasil.