Morphological Observations on Possible Calcium-Protoanemonin Interactions in the Yeast Rhodotorula glutinis

Abstract

Protoanemonin, a lactone present in Ranunculaceae plants, at subinhibitory concentration (19 μg ml⁻¹) caused deep morphogenetic anomalies on the yeast Rhodotorula glutinis. The cell wall was strongly thickened, the nuclei were lobed and irregular in shape, and consistent deposits of calcium aggregates were scattered in the mitochondrial matrix as proved by the cation-precipitating K-pyroantimonate test. The ultrastructural results confirm that the antifungal activity of the protoanemonin is related to the interaction of the compound with cytoplasmic microtubules.