Positive selection of mutants defective in transcriptional repression of riboflavin synthesis by iron in the flavinogenic yeast Pichia guilliermondii. - Boretsky YR; Kapustyak KY; Fayura LR; Stasyk OV; Stenchuk MM; Bobak YP; Drobot LB; Sibirny AA (FEMS yeast research, 2005)