Metabolic Regulation of a Bacterial Cell System with Emphasis onEscherichia coliMetabolism

Abstract

It is quite important to understand the overall metabolic regulation mechanism of bacterial cells such as Escherichia coli from both science (such as biochemistry) and engineering (such as metabolic engineering) points of view. Here, an attempt was made to clarify the overall metabolic regulation mechanism by focusing on the roles of global regulators which detect the culture or growth condition and manipulate a set of metabolic pathways by modulating the related gene expressions. For this, it was considered how the cell responds to a variety of culture environments such as carbon (catabolite regulation), nitrogen, and phosphate limitations, as well as the effects of oxygen level, pH (acid shock), temperature (heat shock), and nutrient starvation.

The polymyxin B-induced transcriptomic response of a clinical, multidrug-resistant Klebsiella pneumoniae involves multiple regulatory elements and intracellular targets

“…This would lead to the activation of genes involved in the response to decreased oxidative power within the cell, including arcB , as we have observed. Besides repressing TCA genes it is also known that the ArcA-ArcB TCRS acts repressing genes encoding primary dehydrogenases such as glpD [31], which would explain our findings.…”

“…These TFs (and corresponding locus) include the OmpR regulator (KP13_00688) as well as the argR gene (KP13_31778) and genes encoding for a putative HTH-transcriptional regulator (KP13_03008; KP13_00251). Also detected was arcB (KP13_03225), part of the TCRS arcAB which has been shown to be highly pleiotropic, and modulates the expression of genes encoding for proteins with membrane modification functions as well as TCA cycle enzymes depending on oxygen levels or redox state [30, 31]. Other TFs detected included rpoH (KP13_08477), rpoN (KP13_03232).…”

Arginine Functionally Improves Clinically Relevant Human Galactose-1-Phosphate Uridylyltransferase (GALT) Variants Expressed in a Prokaryotic Model

“…For non-transformed E. coli DgalT cultured under glucose or glucose plus galactose, the growth curves were indistinguishable, since glucose is the preferred carbon source and galactose represents no toxicity in the presence of this hexose. This absent toxicity of galactose likely results from carbon catabolite repression exerted by glucose, which represses the galactose uptake systems GalP and Mgl (G€ orke and St€ ulke 2008; Misko et al 1987;Shimizu 2013;Steinsiek and Bettenbrock 2012). In the presence of glycerol, transported into E. coli through facilitated diffusion (Chu et al 2002), the growth rate was approximately half of that observed in the presence of glucose, confirming that this polyol is not as efficient as glucose as a carbon source, as previously described (Chu et al 2002).…”

Succinic Semialdehyde Promotes Prosurvival Capability of Agrobacterium tumefaciens

“…In various bacteria, nitrate assimilation and changes in the NADPH/ NADP ratio are closely associated with the generation of reactive oxygen species (ROS) (35). ROS, such as a superoxide anion radical (O 2Ϫ ), hydrogen peroxide (H 2 O 2 ), and hydroxyl radicals (HO Ϫ ), are unavoidably generated during normal respiratory processes, and they can damage diverse cellular molecules (36).…”