Figure 2. Expression and production of virulence factors in V. cholerae is enhanced in the presence of glucose.

(A) Relative expression of virulence-associated genes in the V. cholerae wild-type strain A1552. The virulence inducer bicarbonate was present in all samples. Supplemented carbon sources were lactate and glucose as indicated by the white and black columns, respectively. Statistics were applied using Student's t-test (**, P≤0.01; ***, P≤0.001). (B) Quantification of cholera toxin that was produced upon growth on diverse carbon sources (as indicated). The data were normalized by the OD₆₀₀ values of the bacterial culture. For rice starch-grown cells the OD₆₀₀ value was deduced from the number of counted bacteria. All data represent averages from three independent biological experiments ± SD.