Appearance and properties of L-sorbose-utilizing mutants of Candida albicans obtained on a selective plate.
This is the first report that adaptive mutagenesis can arise by chromosomal nondisjunction, a phenomenon previously associated exclusively with DNA alterations. We previously uncovered a novel regulatory mechanism in Candida albicans in which the assimilation of an alternative sugar, l-sorbose, was determined by copy number of chromosome 5, such that monosomic strains utilized l-sorbose, whereas disomic strains did not. We present evidence that this formation of monosomy of chromosome 5, which is apparently a result of nondisjunction, appeared with increased frequencies after a selective condition was applied, i.e., by adaptive mutagenesis. The rate of formation of l-sorbose-utilizing mutants per viable cell per day ranged from 10(-6) at the initial time of detection to 10(-2) after 4 days of incubation on the selective plate.
Janbon
G
G
Department of Biochemistry, University of Rochester Medical School, Rochester, New York 14642, USA.
Sherman
F
F
Rustchenko
E
E
D002176:Candida albicans / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal / Q000235:genetics*; D003470:Culture Media; D016521:Electrophoresis, Gel, Pulsed-Field; D007700:Kinetics; D016296:Mutagenesis; D010641:Phenotype; D013013:Sorbose / Q000378:metabolism*; D013997:Time Factors
D003470:Culture Media; D013013:Sorbose