Influence of high hydrostatic pressure on the formation of keto and amino acids by a barotolerant strain of Pseudomonas aeruginosa.

The peculiarities of the growth and extracellular accumulation of free keto and amino cids by a barotolerant culture (strain 0798) in culturing on Ran's glucose-mineral medium conditions of 1, 200, 300, and 500 atm were investigated. At a high pressure the culture possesses the ability for extracellular accumulation of free keto and amino acids, pyruvic, alpha-ketoglutaric, and oxaloacetic acids, alanine, and glutamic acid, while under conditions of atmospheric pressure, chiefly valine is accumulated in the medium, and there are no extracellular keto acids. The established specificity of the extracellular accumulation of keto and amino acids under conditions of high hydrostatic and atmospheric pressure is due to the different sensititivy of the enzyme systems participating in the biosynthesis of free keto and amino acids to the influence of high hydrostatic pressure.

[Formation of free ketoacids by barotolerant bacteria under conditions of increased pressure]. / Obrazovanie svobodnykh ketokislot barotolerantnymi bakteriiami v usloviiakh povyshennogo davleniia

The effect of elevated hydrostatic pressure on biosynthesis of keto acids by barotolerant bacteria growing on glucose-mineral media is discussed in this paper. Strains which are more tolerant to the action of pressure can liberate exocellular keto acids. Keto acids are synthesized at a low content of glucose and a relatively high concentration of nitrogen in the presence of dissolved oxygen. Pressure may either induce or inhibit the synthesis. A shift towards oxalacetate in the composition of keto acids caused by the action of pressure shows that anabolism and catabolism are decoupled. Free exocellular keto acids are not found in bacteria, which do not grow at 500 atm. either at atmospheric or elevated pressures; therefore, their metabolism is more balanced. Differences in the growth of barotolerant bacteria, and in biosynthesis of keto acids at elevated pressure, may be caused by different response of various strains and species of barotolerant bacteria to the action of this factor.

[Formation of keto acids by barotolerant marine bacteria under atmospheric pressure]. / Obrazovanie ketokislot barotolerantnymi morskimi bakteriiami pri atmosfernom davlenii

Production of keto acids by washed cells of the barotolerant strains was studied under atmospheric pressure on a glucose-mineral medium in balloons made of the copolymer of ethylene with propylene. Production of keto acids in these conditions requires elevated concentrations of glucose and minimum concentrations of ammonium nitrogen. Active aeration inhibits the accumulation of keto acids by the barotolerant bacteria. The majority of the barotolerant bacteria did not form free extracellular keto acids, other bacteria liberated comparatively small amounts of these acids. The ability to accumulate keto acids was different in particular strains.

[Effect of elevated hydrostatic pressure on the activity of catabolic enzymes in barotolerant bacteria]. / Deistvie povyshennogo gidrostaticheskogo davleniia na aktivnost' kataboliticheskikh fermentov u barotolerantnykh bakterii

The effect of elevated hydrostatic pressure on catabolic enzymes was studied with four strains of barotolerant bacteria isolated from ooze at high depth of the Pacific Ocean. Pseudomonas aeruginosa 0798 and Ps. sociovivum 0913, tolerant to a pressure of 500 atm, have more active catabolic enzymes than Ps. nonliquefaciens 0613 and Ps. acuta 039, which do not grow at a pressure of 500 atm. Changes in the activity of the enzymes caused by elevated hydrostatic pressure are similar to changes caused by the process of the culture aging.