Utilization of Adenine by a Mutant of Candida utilis

Abstract

PREVIOUS work has shown that Candida utilis (strain IMI 23311) efficiently utilizes exogenous adenine for the synthesis of RNA¹. During the course of subsequent investigations², fresh cultures obtained, from the Commonwealth Mycological Institute were found to have undergone mutation. The mutant had a longer generation time than the original strain when grown in rich medium, and failed to grow satisfactorily under conditions used in tracer experiments. Since no culture afterwards supplied by the Commonwealth Mycological Institute was found to have the characteristics of the original strain, experiments were continued with C. utilis strain NCYC 321. This strain had been maintained since 1951 from an original culture of strain IMI 23311 (ref. 3) and was found to have similar growth characteristics to those of the original culture of strain IMI 23311 used in these laboratories. The mutant has now been found to differ from strain NCYC 321 with respect to the utilization of exogenous adenine, and it is desirable to record that strain IMI 23311 no longer has the metabolic characteristics of the organism used in our previous work.