Use of inhibitors for selective isolation and enumeration of cytophagas from natural substrates.

Abstract

Bacillus thuringiensis cells, depending on their physiological state, produce different quantities of exoprotease. Easily metabolizable carbon sources in the medium can affect the process in the opposite way: they inhibit synthesis of the enzyme by the cells in the exponential growth phase, and stimulate it by the sporulating cells. Apparently, cAMP is not an effector of catabolite repression regulating exoprotease synthesis by the cells in the exponential growth phase, inspite of stimulating the enzyme synthesis at the background of easily metabolizable carbon sources. The same effect is produced by cAMP in the absence of additional carbon sources. AMP, adenine, GMP and guanine exhibit a similar action on the enzyme synthesis; the effect is most pronounced in the medium without easily metabolizable carbon sources. The action of cGMP is specific: cGMP inhibits the synthesis of exoprotease in the presence of additional carbon sources, and stimulates it in the absence of easily metabolizable compounds.