Low temperature-induced viable but not culturable state of Ralstonia eutropha and its relationship to accumulated polyhydroxybutyrate.
The culturability of Escherichia coli, Ralstonia eutropha and Bacillus subtilis after incubation in phosphate-buffered saline at either 5°C or 30°C was determined. The culturability of B. subtilis showed little dependence on temperature. The culturability of E. coli rapidly decreased at 30°C but remained almost constant at 5°C. In contrast, the culturability of R. eutropha decreased by three orders of magnitude at 5°C within 24 h but only moderately decreased (one order of magnitude) at 30°C. Remarkably, prolonged incubation of R. eutropha at 30°C resulted in a full recovery of colony forming units in contrast to only a partial recovery at 5°C. Ralstonia eutropha cells at 30°C remained culturable for 3 weeks while culturability at 5°C constantly decreased. The effect of temperature was significantly stronger in a polyhydroxybutyrate-negative mutant. Our data show that accumulated polyhydroxybutyrate has a cold-protective function and can prevent R. eutropha entering the viable but not culturable state.
Institute of Microbiology, University of Stuttgart, 70550 Stuttgart, Germany.
Verena
V
Nowroth
Institute of Microbiology, University of Stuttgart, 70550 Stuttgart, Germany.
Lisa
L
Marquart
Institute of Microbiology, University of Stuttgart, 70550 Stuttgart, Germany dieter.jendrossek@imb.uni-stuttgart.de.
Dieter
D
Jendrossek
D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development*; D003080:Cold Temperature; D015169:Colony Count, Microbial; D020118:Cupriavidus necator / Q000235:genetics / Q000254:growth & development*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development*; D006358:Hot Temperature; D006885:Hydroxybutyrates / Q000378:metabolism*
D006885:Hydroxybutyrates
VBNC; polyhydroxybutyrate; survival; viable but not culturable