Figure 6
Study of the redundancy between Acm2 and Lys2 for cell chaining and autolysis phenotypes. (A) Number of cells per chain in L. plantarum NZ7100 (WT), acm2 mutant (Acm2–), lys2 mutant (Lys2–), and double acm2 lys2 mutant (Acm2– + Lys2–) in different growth conditions (MRS, CDM and SCDM). (B) Number of cells per chain in L. plantarum NZ7100 (WT), acm2 mutant carrying the empty plasmid pNZ8048 (Acm2– + CTL), and acm2 mutant overexpressing acm2 (Acm2– + Acm2+) or lys2 (Acm2– + Lys2+) grown in presence of the nisin inducer in MRS. (C) Autolysis of L. plantarum and its mutant derivatives in presence of Triton X-100 (0.05%). Wild type is represented by a line (WT), acm2 mutant carrying the empty plasmid pNZ8048 (Acm2– + CTL) by black diamonds, and acm2 mutant overexpressing acm2 (Acm2– + Acm2+) and lys2 (Acm2– + Lys2+) by white triangles and crosses, respectively. For panels A and B, mean values ± standard deviations (n=3); significance based on Student’s t test; ***, P value of <0.001. NS, not significantly different. For panel C, mean values of three independent experiments ± standard deviations (with 3 repetitions for each). OD600 values of the wild type, acm2 mutant overexpressing acm2 (Acm2– + Acm2+), and acm2 mutant overexpressing lys2 (Acm2– + Lys2+) are all significantly different from the acm2 mutant carrying the empty plasmid pNZ8048 (Acm2– + CTL) between 2 and 10 h. Significance is based on Student’s t test with a P value of <0.001.