J. Bacteriol., Jun 1996, 2999-3007, Vol 178, No. 11
F Berger, N Morellet, F Menu and P Potier
The psychrotrophic bacterium Arthrobacter globiformis SI55 was grown at 4
and 25 degrees C, and the cell protein contents were analyzed by two-
dimensional electrophoresis. Cells subjected to cold shocks of increasing
magnitude were also analyzed. Correspondence analysis of protein appearance
distinguished four groups of physiological significance. Group I contained
cold shock proteins (Csps) overexpressed only after a large temperature
downshift. Group II contained Csps with optimal expression after mild
shocks. Group III contained proteins overexpressed after all cold shocks.
These last proteins were also overexpressed in cells growing at 4 degrees C
and were considered to be early cold acclimation proteins (Caps). Group IV
contained proteins which were present at high concentrations only in 4
degrees C steady-state cells and appeared to be late Caps. A portion of a
gene very similar to the Escherichia coli cspA gene (encoding protein
CS7.4) was identified. A synthetic peptide was used to produce an antibody
which detected a CS7.4-like protein (A9) by immunoblotting two- dimensional
electrophoresis gels of A. globiformis SI55 total proteins. Unlike
mesophilic microorganisms, this CS7.4-like protein was still produced
during prolonged growth at low temperature, and it might have a particular
adaptive function needed for balanced growth under harsh conditions.
However, A9 was induced at high temperature by chloramphenicol, suggesting
that CS7.4-like proteins have a more general role than their sole
implication in cold acclimation processes.
Copyright © 1996, American Society for Microbiology
Cold shock and cold acclimation proteins in the psychrotrophic bacterium Arthrobacter globiformis SI55
Laboratoire d'Ecologie Microbienne du Sol, Unite Mixte de Recherche Centre National de la Recherche Scientifique 5557, Universite Claude Bernard, Lyon I, France.
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