A metabolic inquiry into the iridescent lysis of agar lawns of Pseudomonas aeruginosa strain 227.

Abstract

The iridescent lysis found in agar lawns of Pseudomonas aeruginosa strain 227 was suppressed in the presence of dextrose and increased by glycerol. The acidic end products in the dextrose cultures were found to be pyruvic acid and 2-oxoglutaric acid. The incorporation of pyruvic acid into gradient agar cultures increased iridescent lysis, but the reduction of the iridescent lysis by 2-oxoglutarate was variable and unpredictable. The comparative activities of isocitrate lyase and 2-oxoglutarate dehydrogenase were higher in dextrose-grown cells than in glycerolgrown cells. Activities of isocitrate dehydrogenase and fumarate dehydrogenase were greater in glycerol-grown cells. The production of quinolinols and pyocyanine was increased by glycerol and decreased by dextrose. When these end products were prematurely introduced into freshly sown glycerol cultures, both inhibited iridescence, but only pyocyanine inhibited growth. The difference in growth inhibition by quinolinols and pyocyanine may be attributable to solubility or concentration.