The role of metabolic energy in the lethal action of basic proteins on Candida albicans

Comparative studies were made on the destructive effects of certain basic proteins on a strain of Candida albicans and two of its respiration-impaired mutants. Both by direct plate counts of survivors and by quantitative ultraviolet spectrophotometric analyses of released cellular constituents, the respiration-impaired mutants were less vulnerable to the destructive actions of the basic proteins than were ordinary wild-type cells. The lethal incidence and the ultraviolet absorbing cellular substances released from wild-type cells by the proteins were markedly decreased in the presence of the oxidative phosphorylation uncouplers sodium azide, 2,4-dinitrophenol, and salicylanide and approximately equal to the effects produced on an oxidative phosphorylation mutant not treated with the uncouplers. The heightened resistance of a culture through mutational or chemical impairment of its respiratory system suggests a role of metabolic energy in the destructive action of various basic proteins on yeast cells.