FIG. 1.

cAMP levels in M. smegmatis during growth and stress conditions. (A) Intracellular cAMP levels during growth of wild-type M. smegmatis. (B) Total amount of extracellular cAMP (solid line) present in a culture (total volume, 10 ml). Extracellular cAMP (dotted line) of the same cultures is expressed per 10⁸ cells. C. M. smegmatis cells were cultured for 30 h, resuspended in the medium indicated, and cultured for 5 h, following which the intracellular cAMP level was measured. (D) M. smegmatis cells were cultured for 30 h, and cells were resuspended in fresh medium and cultured for another 1.5 h at 37°C or at 42°C. Alternatively, cells were resuspended in medium containing 0.05% SDS or in PBS and cultured for 1.5 h. The intracellular cAMP level was measured at the end of 1.5 h. All data shown represent the means ± standard errors of the means (SEM) of duplicate determinations, with each assay being performed three times.