Cold shock proteins and cold acclimation proteins in a psychrotrophic bacterium

The synthesis of proteins in the psychrotrophic bacterium Bacillus psychrophilus in response to both cold shock and continuous growth at low temperatures was examined. Cold shocks of 20 to 0, 5, or 10 °C resulted in the induction of nine, seven, and five cold shock proteins, respectively, as determined by 2-dimensional gel electrophoresis and computing scanning laser densitometry. Two cold shock proteins, with molecular masses of 61 and 34 kDa, which were induced in B. psychrophilus by cold shocks of 20 to 0 or 5 °C, were not induced in a cold-sensitive mutant of B. psychrophilus. Analysis of protein profiles of B. psychrophilus during continuous growth at 0, 5, or 10 °C revealed the synthesis of 11, 10, and 4 cold acclimation proteins, respectively. Some of these cold acclimation proteins were similar to cold shock proteins. In addition, the relative synthesis of both cold shock proteins and cold acclimation proteins increased with decreasing temperature. Thus, both types of proteins increased both in number and relative synthesis in response to cold shock and continuous growth at low temperature. Key words: cold shock proteins, cold acclimation proteins, psychrotrophic bacterium.

Induction of protein synthesis in response to cold shock in the psychrotrophic yeast Trichosporon pullulans

The synthesis of proteins in response to a cold shock in the psychrotrophic yeast Trichosporon pullulans was examined. Two-dimensional electrophoretic analysis of a 21 to 5 °C cold shock revealed the induction of 26 cold-shock proteins (csps) at the maximum induction time of 12 h. The induction of only 10 csps after a 24 to 5 °C cold shock suggested that the growth of cells above their optimum growth temperature reduced their ability to induce csps. Comparison of the csp profile obtained after a 15 to a 5 °C cold shock with the profile for the 21 to 5 °C cold shock suggested that the range of the cold shock influences which proteins are induced. Key words: cold-shock proteins, psychrotrophic yeast.