FIG. 2.

Expression of a txeR-gusA fusion in stationary-phase cells of C. perfringens. A DNA fragment containing the promoter region of txeR gene was cloned in the reporter fusion vector pTUM177 and introduced into C. perfringens with or without the txeR gene in trans. β-Glucuronidase activity of late-stationary-phase cells grown in TY or TYG medium was determined as described previously (7). In control experiments, cells carrying the fusion vector alone were assayed. Solid bars, TY medium, no TxeR; open bars, TYG medium, no TxeR; striped bars, TY medium with TxeR; checkered bars, TYG medium with TxeR.