Fig. 4.

Growth curve of wild type and genetically engineered V. cholerae strains in rich (LB) and nutritionally defined culture medium (M9). The El Tor strain N16961 and its derivatives were grown individually in monocultures in LB (A) and M9 (B), and the growth of the bacterial cells was monitored by measuring the optical density of the culture at 600 nm (OD₆₀₀) in a spectrophotometer at different time points. Growth competition between ΔVSP-1ΔVSP-2 N16961 and O395 was also done in rich (C) and minimal medium (D) in a cocultured medium by inoculating similar number of cells together (1:1). CFU count of each strain was determined by plating the culture in rich medium (LA) supplemented with specific antibiotic. TCR = TLCΦ-CTXΦ-RS1Φ.