Expression of carbonic anhydrase in neisseriae and other heterotrophic bacteria

A diverse range of heterotrophic bacteria was screened for the presence of carbonic anhydrase (CA) activity, sensitivity to inhibition of growth by acetazolamide (CA inhibitor), and the presence of protein binding monospecific antibody prepared against purified Neisseria sicca CA. CA activity was demonstrated only in strains of N. sicca and N. gonorrhoeae. However, all Neisseria strains, including various isolates of N. meningitidis and N. lactamica, were sensitive to acetazolamide, when grown in air, and showed serological cross-reaction with N. sicca CA. Strains of other genera were resistant to acetazolamide. A number of strains including members of the genera Pseudomonas, Staphylococcus, Streptococcus, Serratia and Proteus also strongly expressed a gene product(s) immunologically related to CA. The presence of CA cross-reacting proteins, which lack hydrase activity, is discussed in relation to the function of the various mammalian CA isoenzymes.