Stress-survival responses of a carbon-starved p-nitrophenol-mineralizing Moraxella strain in river water.
The effect of carbon starvation on the stress-resistant responses of a p-nitrophenol-mineralizing Moraxella strain was examined in both buffer and river water samples. The Moraxella strain showed optimal stress-resistant responses in a minimal salt buffer when carbon-starved for 1-2 d. In the buffer system, the 1- and 2-day carbon-starved Moraxella cultures survived about 150-, 200-, and 100-fold better than the non-starved cultures when exposed to 43.5 degrees C, 2.7 mol/L NaCl, and 500 micromol/L H2O2 for 4 h, respectively. A green fluorescent protein gene- (gfp) labelled derivative of the Moraxella strain was used to examine the stress-resistant responses of the bacterium in natural river water microcosms. The carbon-starved gfp-labelled Moraxella strain also showed stress-resistant responses against heat, osmotic, and oxidative stresses in the river water samples. Despite the stress-tolerant capability of the carbon-starved gfp-labelled Moraxella cells, they did not exhibit any survival advantage over their non-starved counterparts when inoculated into river water microcosms and incubated at 10 and 22 degrees C for 14 d.
Moore
Michael
M
Department of Biology, Lakehead University, Thunder Bay, ON, Canada.
Trevors
Jack
J
Lee
Hung
H
Leung
Kam Tin
KT
D001673:Biodegradation, Environmental; D002021:Buffers; D002244:Carbon / Q000378:metabolism*; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D009016:Moraxella / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D009596:Nitrophenols / Q000378:metabolism*; D045483:Rivers / Q000382:microbiology*
D002021:Buffers; D003470:Culture Media; D009596:Nitrophenols; D049452:Green Fluorescent Proteins; D002244:Carbon