Brevianamides A and B Are Formed Only After Conidiation Has Begun in Solid Cultures of Penicillium brevicompactum.

In cultures of Penicillium brevicompactum grown on Czapek-Dox agar or on circles of dialysis membrane placed on Czapek-Dox agar, brevianamides A and B first appeared after conidiation had begun. The presence of these brevianamides imparted a yellow-green fluorescence to the penicilli and to the upper section of the conidiophores of actively conidiating cultures. Experiments with replacement cultures indicated that medium nutrient levels had little direct effect on brevianamide production. If P. brevicompactum was grown between two circles of dialysis membrane, no aerial hyphae were formed, and brevianamide production was not observed. Three brevianamide-minus mutants of P. brevicompactum were isolated.