With the exception of cysK and sbp , mutants in all other CysB-regulated genes showed little or no activity on swim plates .
Wild-type S. typhimu-rium containing CysB-regulated promoter reporters for sbp , cysP , and cysJ were grown in M9-minimal-medium with sulfate as the sole sulfur source with and without 50 mM methyl viologen to cause mild oxidative-stress .