Cyclic AMP-CRP Modulates the Cell Morphology of in High-Glucose Environment.

Bacteria can modify their morphology in response to environmental stimuli for survival or host defense evasion. The rich glucose or in the Luria-Bertani (LB) medium shortened the cell length of . The environmental glucose decreased the levels of cyclic AMP (cAMP) and the transcription of , which declined the cAMP-cAMP receptor protein (cAMP-CRP) activity. The cell length of deletion mutant was significantly shorter than that of the wild type (0.981 ± 0.057 μm vs. 2.415 ± 0.075 μm, < 0.001). These results indicated that the high environmental glucose alters the bacterial morphology to a round form through regulating the activity of cAMP-CRP complex. Comparative proteomics analysis showed increased expression of 10 proteins involved in cell division or cell wall biosynthesis in the deletion strain. Five of them (A, B, C, I, and F) were selected to verify their expression in the high-glucose environment, and overexpression of B or F shortened the bacterial length similar to that of the deletion strain. Electrophoretic mobility shift assay indicated that CRP directly negatively regulates the transcription of B and F by binding to the promoter regions. This study first proved the role and partial regulation mechanism of CRP in altering cell morphology during infection and provided a theoretical basis for elucidating the mechanism in diabetes mellitus susceptible to .