TABLE 5.

Effects of different carbon sources on citZ expression in L. monocytogenes

Strain	Fusion	β-Galactosidase activity (Miller units) with the following carbon sources:
		Glucose	Mannose	Glycerol	Citrate
LMM18	(lmo1568-citZ)-lacZ (C)	4.6	4.1 ± 0.2	5.2 ± 1.2	4.1 ± 0.2
LMM19	citZ-lacZ (D)	0.6 ± 0.02	0.7 ± 0.3	0.7 ± 0.3	0.8 ± 0.3
LMM23	(lmo1568-citZ)-lacZ (C) in ccpC null mutant	28 ± 1.9	31 ± 2.2	29 ± 2.2	26 ± 2.2
LMM24	citZ-lacZ (D) in ccpC null mutant	0.9 ± 0.3	0.9 ± 0.2	0.6 ± 0.3	0.9 ± 0.2

^a β-Galactosidase activity was determined for wild-type and ccpC null mutant strains of L. monocytogenes carrying various lacZ fusions (Fig. 2). The organisms were grown at 30°C in IMM medium. Samples were collected in mid-exponential phase (OD₆₀₀, 0.5) for all of the sugars tested except citrate. Samples were collected at an OD₆₀₀ of 0.1 or 0.2 when citrate was used as the sole carbon source. The results are the averages ± standard deviations of two independent experiments (except for the strain with fusion C in glucose medium). In all experiments, multiple samples were taken during the exponential growth phase.