Effect of chloramphenicol on the electron systems in Ustilago cynodontis

The mycelial cells of Ustilago cynodontis possess at least two electron transport systems: a cyanide-sensitive cytochrome pathway, which represents the major route for electron transport, and an alternative cyanide-insensitive pathway, inhibited by salicylhydroxamic acid. In the presence of chloramphenicol in the culture medium, mycelial cells respire only by the alternatuve chain. The stable induced yeast-like cells, obtained by prolonged chloramphenicol treatment of the mycelial cells, respire as the untreated mycelial cells; this result indicates that the phenotypic change induced by chloramphenicol is not related to a modification of the respiratory system.