fulltext.study @t Gmail

Effects of arcA and arcB genes knockout on the metabolism in Escherichia coli under anaerobic and microaerobic conditions

Paper ID Volume ID Publish Year Pages File Format Full-Text
4330 221 2008 8 PDF Available
Title
Effects of arcA and arcB genes knockout on the metabolism in Escherichia coli under anaerobic and microaerobic conditions
Abstract

The Arc system is a two-component regulatory system composed of ArcA and ArcB in Escherichia coli. In the present study, the effects of arcA and arcB genes knockout on the TCA cycle activation in E. coli were investigated for the anaerobic and microaerobic conditions. Under anaerobic condition, the TCA cycle was up-regulated along with high lactate production, together with up-regulation of LDH for arcB mutant as compared with the parent strain. Due to down-regulation of aceE, aceF and lpdA genes which code for PDHc and low activity of Pfl in arcB mutant, the glycolysis as well as oxidative pentose phosphate pathway was down-regulated under anaerobic condition. The TCA cycle enzymes were further up-regulated when nitrate was added by modifying the redox state along with lower lactate production for arcB mutant. Different from the case of anaerobic condition, the glycolysis was activated under microaerobic condition, which may be partly due to the increased activity of PDHc encoded by aceE, F and lpdA genes. Under microaerobic condition, the TCA cycle genes together with their corresponding enzymes were up-regulated for arcB mutant as compared with the parent strain. These characteristics were further enhanced in arcA mutant as compared with the case of arcB mutant. The up-regulation of the TCA cycle together with down-regulation of cydB gene expression caused higher redox state in the arcA/B mutants, which in turn repressed the TCA cycle. Then the TCA cycle could be further increased by the addition of nicotinic acid (NA).

Keywords
Escherichia coli; arcA; arcB; Microaerobic condition
First Page Preview
Effects of arcA and arcB genes knockout on the metabolism in Escherichia coli under anaerobic and microaerobic conditions
Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 42, Issue 3, 1 December 2008, Pages 229–236
Authors
, ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering