CHOLINESTERASE, ACID-PHOSPHATASE, AND PHOSPHOLIPASE-C OF PSEUDOMONAS-AERUGINOSA UNDER HYPEROSMOTIC CONDITIONS IN A HIGH-PHOSPHATE MEDIUM

The presence of low chlorine or betaine concentrations in a culture me dium containing succinate, NH4Cl, and inorganic phosphate (Pi) as the carbon, nitrogen, and phosphate sources, respectively, permits the gro wth of Pseudomonas aeruginosa in a hyperosmolar medium. Dimethylglycin e, acethylcholine, and phosphorylcholine were less effective as osmopr otectants than choline or betaine. Other alkylammonium compounds teste d were virtually ineffective in this capacity. Bacterial growth was al so observed in a hyperosmolar medium when choline was the sole carbon and nitrogen source. Choline could act as an osmoprotectant under all the conditions tested. However, the production of cholinesterase (ChE) , acid phosphatase (Ac.Pase) and phospholipase C (PLC) took place only when choline was the carbon and nitrogen source. This fact confirms t hat the synthesis of PLC may occur even in the presence of a high Pi c oncentration in the medium. Inasmuch as in a high-Pi medium the synthe sis of PLC and Ac.Pase (phosphorylcholine phosphatase) is dependent on ly on choline metabolism, it is postulated that both enzymes are invol ved in a set of reactions coordinated to produce the breakdown of the membrane phospholipids of the host cell in a hyperosmotic medium.