Effect of rpoS gene knockout on the metabolism of Escherichia coli during exponential growth phase and early stationary phase based on gene expressions, enzyme activities and intracellular metabolite concentrations
✍ Scribed by Mahbuba Rahman; Mohammad Rubayet Hasan; Takahiro Oba; Kazuyuki Shimizu
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 293 KB
- Volume
- 94
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
Abstract
The RNA polymerase sigma factor, encoded by __rpo__S gene, controls the expression of a large number of genes in Escherichia coli under stress conditions. The present study investigated the growth characteristics and metabolic pathways of __rpo__S gene knockout mutant of E. coli growing in LB media under aerobic condition. The analyses were made based on gene expressions obtained by DNA microarray and RT‐PCR, enzyme activities and intracellular metabolite concentrations at the exponential and early stationary phases of growth. Although the glucose utilization pattern of the mutant was similar to the parent strain, the mutant failed to utilize acetate throughout the cultivation period. Microarray data indicated that the expression levels of several important genes of acetate metabolism such as acs, __ace__AB, __cys__DEK, __fad__R, etc. were significantly altered in the absence of __rpo__S gene. Interestingly, there was an increased activity of TCA cycle during the exponential growth phase, which was gradually diminished at the onset of stationary phase. Moreover, __rpo__S mutation had profound effect on the expression of several other genes of E. coli metabolic pathways that were not described earlier. The changes in the gene expressions, enzyme activities and intracellular metabolite concentrations of the __rpo__S mutant are discussed in details with reference to the major metabolic pathways of E. coli. © 2006 Wiley Periodicals, Inc.