COMPOSITION OF CELL WALLS OF AGEING PSEUDOMONAS AERUGINOSA AND SALMONELLA BETHESDA.

Abstract

Summary: Anaerobic cultures of Pseudomonas aeruginosa died rapidly in the absence of nitrate and death was normally followed by extensive autolysis. A mutant which did not undergo extensive autolysis was isolated. Anaerobic cultures of Salmonella bethesda did not die or lyse even after prolonged incubation. The protein and lipid content of the parent P. aeruginosa cell walls altered during ageing in contrast to S. bethesda walls which did not alter greatly as the organisms aged. The amino acid and amino sugar content of the three strains was determined. The diaminopimelic acid, glycine, alanine, glutamic acid, glucosamine, muramic acid and glucose content of the parent cell walls decreased by 50% as the organisms aged. The mutant strain of P. aeruginosa and S. bethesda walls showed no such change in ageing. Chemical changes similar to ageing could be produced in the cell walls of P. aeruginosa by incubation with an autolysin obtained from old cultures of the parent strain.