Fig. 8.

Responsiveness of NspS mutants to norspermidine. Effect of addition of norspermidine on biofilm formation of mutant clones. Each mutant clone is listed only by the single-missense mutation present in that strain of V. cholerae ΔnspS pACYC184::nspS-V5. The positive control is V. cholerae ΔnspS pACYC184::nspS-V5 and the negative control is V. cholerae ΔnspS pACYC184. A t-test was used to compare biofilm formation between LB only (dark grey bars) and LB +100 µM norspermidine (light grey bars) for each individual mutant clone analysed. Clones that showed a statistical difference (P value of <0.05) in biofilm formation in the presence of norspermidine were deemed responsive. Experiments were performed in triplicate and the error bars show the standard deviation of three biological replicates. For five mutants indicated by stars, only two replicates were performed due to COVID-19-related limitations. (a) Responsive clones. (b) Non-responsive clones.