CHANGES OF VIABILITY AND PROTEIN-SYNTHESIZING ACTIVITY IN PSYCHROTROPHIC AND MESOPHILIC BACTERIA BY CHILLING AT 0°

Abstract

When Pseudomonas sp. strain 351 (P. 351), a psychrotroph, and Pseudomonas aeruginosa and Bacillus subtilis, mesophiles, were exposed to 0°, viability of P. 351 was little changed during the chilling for 16 days, whereas that of P. aeruginosa and B. subtilis was reduced to about 40% after 2 and 4 days of chilling, and was lost completely after 16 and 8 days, respectively. Protein-synthesizing activity of P. 351 at 0°, 10°, and 20° was little changed or stimulated by chilling for 4 days, whereas that of P. aeruginosa was markedly depressed by the same treatment. However, RNA synthesis was activated by chilling for 4 days both in P. 351 and P. aeruginosa. From these results, cold-sensitivity of the protein-synthesizing system in P. aeruginosa seems to be closely related with diminution of its viability in low temperatures.