Fig. 5.

Pandemic V. cholerae strains are transformation variable.

A, B. Different V. cholerae O1 El Tor pandemic isolates were tested for their natural transformability (A) or their HapR production (B). Strain N16961‐hapR ^Rep is a genetically engineered N16961 variant with a repaired hapR gene.

C, D. The O139 serogroup strain MO10 and its hapR‐repaired variant (MO10‐hapR ^Rep) were tested for their natural transformability on chitin (C; together with the indicated knock‐out mutants of these two strain backgrounds) or under TfoX‐inducible conditions (D). Details as described in Fig. 2. Statistical analyses were performed to compare diverse strains to the reference strain of this study, A1552, using a one‐way ANOVA on log‐transformed data with Sidak's multiple comparisons test. <, below detection limit. The detection limit was used for statistical analysis for conditions in which no transformants were recovered. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; ns, not significant.