The effects of threshold levels of phenylmercuric acetate (PMA) on the paint mildew Aureobasidium pullulans

Abstract

Pure cultures of the paint mildew Aureobasidium pullulans were grown on solid and liquid media, both defined and undefined. Various concentrations of phenylmercuric acetate (PMA) were incorporated in the media, and threshold inhibitory levels were determined. Electron microscopy observations were performed on A. pullulans grown on a defined media which promoted hyphal growth.In the presence of threshold levels of PMA at 200 parts per billion, the cells of A. pullulans were swollen but did not germinate into hyphal filaments. Blastospore production was reduced when compared with non-mercury-containing cultures. The membrane systems of the cells were markedly affected in that the plasma membrane and nuclear envelope were ill defined or wavy in sectional view and the mitochondrial cristae were swollen. Endoplasmic reticulum and microfilament bundles were restricted or lacking in treated cultures.