title: Adenylate cyclase activity during phenotypic variation of Bordetella pertussis.
abstract: During MgSO4-induced modulation of Bordetella pertussis, adenylate cyclase activity, histamine-sensitizing activity (HSA) and the major cell-envelope polypeptides with Mr 28000 and 30000 (X polypeptides) were lost synchronously at a rate which could be accounted for by a simple growth-dilution effect. MgSO4 and other compounds which induced the above phenotypic change caused little inhibition of adenylate cyclase activity. Nicotinic acid was the sole exception and at 4.1 mM-caused 60% inhibition of activity. Lysates of modulated cells, mixed with lysates of unmodulated cells, had no effect on either adenylate cyclase activity or HSA. Protein synthesis was a prerequisite for MgSO4-induced modulation and also for the reversal of this process. Exogenous cAMP and dibutyryl cAMP (5 mM) had no counteracting effect on MgSO4- or nicotinic acid-induced modulation. The concentration of MgSO4 required to induce loss of the X polypeptides (10 to 11 mM) was not altered by promoting adenylate cyclase activity by including an activator in the growth medium. In one culture containing 10 mM-MgSO4 and activator, partial loss of the X polypeptides occurred and yet the extracellular cAMP concentration was twice that of cultures without activator and where full expression of the X polypeptides occurred. [3H]cAMP-binding activity was detected in cell extracts of several strains of B. pertussis, but antiserum against purified Escherichia coli catabolite repressor protein gave no reaction with B. pertussis cell extracts. Respiration rates with amino acids were similar for modulated and unmodulated variants and an avirulent strain of B. pertussis. These results are discussed in relation to a possible causal role for adenylate cyclase in modulation of B. pertussis.
authors.forename: R M
authors.initials: RM
authors.lastname: Brownlie
authors.forename: J G
authors.initials: JG
authors.lastname: Coote
authors.forename: R
authors.initials: R
authors.lastname: Parton
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D001886:Bordetella pertussis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D002701:Chloramphenicol / Q000494:pharmacology; D003470:Culture Media; D000242:Cyclic AMP / Q000378:metabolism; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D008278:Magnesium Sulfate / Q000494:pharmacology; D010641:Phenotype; D012097:Repressor Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D012097:Repressor Proteins; D002701:Chloramphenicol; D008278:Magnesium Sulfate; D000242:Cyclic AMP; D000262:Adenylyl Cyclases