Electron spin resonance evaluation of pigment accumulation during asexual sporulation in Aspergillus flavus

Abstract

The association between pigment accumulation and a free radical electron spin resonance (ESR) signal produced during sporulation in Aspergillus flavus was investigated. In wild-type cultures, the onset of the ESR signal coincided with the onset of both pigmentation and sporulation. Mutant colonies, affected in their pigmentation and/or their ability to produce conidia, failed to give a free radical signal. However, pigmentation apparently was not essential for either sporulation or spore germination in A. flavus. Pigmentless conidia were obtained which germinated as well as wild-type conidia. There did appear, though, to be some form of association between pigment accumulation and sporulation, since all the asporogenous mutants which were isolated also were non-pigmented.