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. 2011 Nov;193(21):6057–6069. doi: 10.1128/JB.05671-11

Fig. 8.

Fig. 8.

Expression of the S. marcescens Db10 type VI secretion system is not dependent on the system being functional. (A and B) β-Galactosidase activity of chromosomal T6SS-lacZ reporter fusions in strains of S. marcescens Db10 grown in LB medium at 30°C. Strain SLM8 has a nondisruptive insertion of lacZ between SMA2274 and SMA2275. Strain SLM9 is a T6SS mutant, with lacZ replacing SMA2274 (ΔclpV::lacZ). In panel A, the β-galactosidase activity of SLM8 and SLM9 was measured throughout growth. In panel B, the β-galactosidase activity of SLM8 and SLM9 carrying either the control plasmid (pSUPROM, Vector) or a plasmid supplying ClpV in trans (pSC039) was measured at the 7-h and 9-h time points. β-Galactosidase activity is expressed per cell (see Materials and Methods), and bars show means ± SEM (n=3). (C) Anti-Hcp immunoblots of cellular and secreted proteins from the parental strain SLM1 (WT, Lac−), SLM8, and SLM9 (top) and from SLM8 and SLM9 carrying the control plasmid (pSUPROM, Vector) or a plasmid supplying ClpV in trans (pSC039) (bottom). Hcp is indicated by a black arrow. (D and E) Recovery of viable E. coli MC4100 cells after coculture with wild-type S. marcescens Db10 (WT) or strains SJC3 (ΔclpV), SLM8, and SLM9 (D) or after coculture with the wild type or SLM9 carrying pSUPROM or pSC039 (E). Points show means ± SEM (n ≥ 3).