RT Journal Article SR Electronic(1) A1 Wiater, A. A1 Filutowicz, M. A1 Hulanicka, D.YR 1982 T1 A New Class of Mutants of the cysB Regulatory Gene for Cysteine Biosynthesis in Salmonella typhimurium JF Microbiology, VO 128 IS 8 SP 1785 OP 1790 DO https://doi.org/10.1099/00221287-128-8-1785 PB Microbiology Society, SN 1465-2080, AB A new class of regulatory mutants in the cysB locus has been isolated by plating cysM strains, under anaerobic conditions, on medium containing 1,2,4-triazole. The isolated cysB mutants are cysteine prototrophs and triazole-resistant, although the levels of cysteine and O-acetyl-l-serine sulphydrylase are not changed. In contrast to the constitutive cysB mutants identified previously, the expression of the cysteine biosynthetic enzymes in the newly isolated mutants is regulated by the same factors as in wild-type strains. In the double mutant cysE cysB2971, the cysteine biosynthetic enzymes are absent with the exception of O-acetyl-l-serine sulphydrylase., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-128-8-1785