A ction of cycloheximide on Zygosaccharomyces soja.

Tsukada, Yoji (Kyoto University, Kyoto, Japan), Tsunetake Sugimori, Kazutami Imai, and Hideo Katagiri. Action of cycloheximide on Zygosaccharomyces soja. J. Bacteriol. 83:70-75. 1962.-Cycloheximide is known to inhibit the growth of some species of Saccharomyces and other fungi. A new type of action of this antibiotic, with Zygosaccharomyces soja as the test organism, is described in this paper. Growth of Z. soja was completely inhibited under aerobic conditions by cycloheximide in concentrations of more than 5 mug per ml of culture solution. Continued shaking of the culture for more than 96 hr in the presence of an inhibitory amount of cycloheximide restored growth, accompanied by the excretion of riboflavin to the extent of 30 mug per ml of culture solution. In the cells recovering from cycloheximide inhibition, the type of glucose metabolism differed from that in the mother strain; a respiratory quotient of 4 with the mother strain fell to 1 in the progeny. Glucose metabolism (O(2) uptake and CO(2) evolution) by resting cells was investigated, and it was concluded that inhibition of glycolysis was not significant. This was verified by comparing various dehydrogenase activities in the cell-free extract. There were essentially no differences between riboflavin-forming and nonriboflavin-forming cells. The presence of the hexose monophosphate shunt was deduced from the fact that glucose-6-phosphate dehydrogenase activity was the strongest of the various dehydrogenase activities.