PATHOGENICITY OF PSEUDOMONAS-AERUGINOSA ACID ITS RELATIONSHIP TO THE CHOLINE METABOLISM THROUGH THE ACTION OF CHOLINESTERASE, ACID-PHOSPHATASE, AND PHOSPHOLIPASE-C

The increase of cholinesterase (ChE), acid phosphatase (Ac.Pase), and phospholipase C (PLC) activities by Pseudomonas aeruginosa was associa ted with the choline consumption in growth media of varied composition (high or low P-i concentrations, presence or absence of ammonium ion, amino acids, polyamines, peptone, or tricarboxylic acid cycle interme diates). The highest production of the three enzymes occurred in the l ate stationary growth phase. The simultaneous presence of alkaline pho sphatase (Alk.Pase) and the above enzymes was noted when the bacteria were grown in low P-i medium plus choline, in the absence of a preferr ed carbon source. The importance of choline in the production of ChE, Ac.Pase, and PLC was observed in either clinical isolates or collectio n strains of P. aeruginosa. These enzymes catalyze the hydrolysis of a cetylcholine, phosphorylcholine, and phosphatidylcholine. Through thei r action the bacteria may break down various compounds (e.g., acetylch oline, from the corneal epithelium; lung surfactant dipalmitoylphospha tidylcholine; phosphorylcholine, a product of the PLC action) or cell membranes through the coordinated action of PLC and Ac.Pase or Alk.Pas e. The final consequence of the action of these enzymes is an increase of the free choline concentration. Extrapolated to an in vivo situati on, if the stationary growth phase resembles the conditions that P. ae ruginosa encounters in its natural environments, then it is possible t o include choline among the factors promoting the pathogenicity of thi s bacterium.