Asexual developmental markers in an aflatoxigenic strain of Aspergillus parasiticus.

The relationships between specific asexual development stages of Aspergillus parasiticus and potential enzyme markers of these stages were established. Competence was reached when culture age was 22.6 h for an initial inoculum level of 3.0 X 10(2) conidia X mL-1 and 8.09 h for an initial inoculum level of 2.0 X 10(4) conidia X mL-1. The appearance of laccase activity was correlated with the development of conidia. Laccase activity was detected only in conidiating cultures. Activity was inhibited in shaking cultures due to inhibition of conidiation. Laccase activity reached a maximum in cultures after 120 h. Inducible nitrate reductase activity was detected in A. parasiticus cultures after competence was established.