Abstract
Exogenous derivatives of cyclic [c]GMP, 8-bromo- and N2,O2''-dibutyryl cGMP, coordinately repress surface structure differentiation in C. crescentus. Growth in the presence of cGMP derivatives resulted in the loss of flagella and pili formation and concomitant resistance to DNA phage .vphi.CbK and RNA phage .vphi.Cb5 infection without affecting growth rate, stalk formation and equatorial cell division. The effect of cGMP derivatives was the repression of synthesis of specific structural proteins. This effect may be reversed by exogenous N6,O2''-dibutyryl cAMP, and mutants resistant to repression by cGMP derivatives exhibited a pleiotropic phenotype affecting a cAMP-mediated event.