Fig. 1.

QS and cyclic di-GMP signaling and linked phenotypes in V. cholerae. V. cholerae exhibits an inverse relationship between cell density and intracellular c-di-GMP. Under HCD conditions where there is a high concentration of autoinducers, the intracellular concentration of c-di-GMP is low (11, 12). In HCD conditions, cells have increased curvature and a decreased propensity to adhere to surfaces and form biofilms. Conversely, cells in LCD conditions have low concentrations of autoinducers and high c-di-GMP (reviewed in ref. 13). Under LCD conditions, cells are more likely to form biofilms (14). Additionally, V. cholerae loses its canonical curved-rod shape and appears as straight rods (6).