In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 75, No. 12 ( 2009-06-15), p. 3903-3911
Abstract:
Pseudomonas mandelii liquid cultures were studied to determine the effect of pH and temperature on denitrification gene expression, which was quantified by quantitative reverse transcription-PCR. Denitrification was measured by the accumulation of nitrous oxide (N 2 O) in the headspace in the presence of acetylene. Levels of gene expression of nirS and cnorB at pH 5 were 539-fold and 6,190-fold lower, respectively, than the levels of gene expression for cells grown at pH 6, 7, and 8 between 4 h and 8 h. Cumulative denitrification levels were 28 μmol, 63 μmol, and 22 μmol at pH 6, 7, and 8, respectively, at 8 h, whereas negligible denitrification was measured at pH 5. P. mandelii cells grown at 20°C and 30°C exhibited 9-fold and 94-fold increases in levels of cnorB expression between 0 h and 2 h, respectively, and an average 17-fold increase in levels of nirS gene expression. In contrast, induction of cnorB and nirS gene expression for P. mandelii cells grown at 10°C did not occur in the first 4 h. Levels of cumulative denitrification at 10 h were 6.6 μmol for P. mandelii cells grown at 10°C and 20°C and 30 μmol for cells grown at 30°C. Overall, levels of cnorB and nirS expression were relatively insensitive to pH values over the range of pH 6 to 8 but were substantially reduced at pH 5, whereas gene expression was sensitive to temperature, with induction and time to achieve maximum gene expression delayed as the temperature decreased from 30°C. Low pH and temperature negatively affected denitrification activity.
Type of Medium:
Online Resource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/AEM.00080-09
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2009
detail.hit.zdb_id:
223011-2
detail.hit.zdb_id:
1478346-0
SSG:
12
