Metabolic regulation in Escherichia coli in response to culture environments via global regulators

2011 ◽  
Vol 6 (11) ◽  
pp. 1330-1341 ◽  
Author(s):  
Yu Matsuoka ◽  
Kazuyuki Shimizu
Keyword(s):  
Escherichia Coli ◽  
Metabolic Regulation ◽  
Global Regulators

scholarly journals Metabolic Regulation of a Bacterial Cell System with Emphasis on Escherichia coli Metabolism

2013 ◽  
Vol 2013 ◽  
pp. 1-47 ◽  
Author(s):  
Kazuyuki Shimizu
Keyword(s):  
Escherichia Coli ◽  
Metabolic Regulation ◽  
Cell System ◽  
Regulation Mechanism ◽  
Bacterial Cells ◽  
Gene Expressions ◽  
Global Regulators ◽  
Acid Shock ◽  
Carbon Catabolite Regulation ◽  
Catabolite Regulation

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.

scholarly journals Escherichia coli Harboring a Natural IncF Conjugative F Plasmid Develops Complex Mature Biofilms by Stimulating Synthesis of Colanic Acid and Curli

2008 ◽  
Vol 190 (22) ◽  
pp. 7479-7490 ◽  
Author(s):  
Thithiwat May ◽  
Satoshi Okabe
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Three Dimensional ◽  
F Plasmid ◽  
Form Complex ◽  
Global Regulators ◽  
E Coli ◽  
Colanic Acid ◽  
Regulatory Systems ◽  
Initial Deposition

ABSTRACT It has been shown that Escherichia coli harboring the derepressed IncFI and IncFII conjugative F plasmids form complex mature biofilms by using their F-pilus connections, whereas a plasmid-free strain forms only patchy biofilms. Therefore, in this study we investigated the contribution of a natural IncF conjugative F plasmid to the formation of E. coli biofilms. Unlike the presence of a derepressed F plasmid, the presence of a natural IncF F plasmid promoted biofilm formation by generating the cell-to-cell mating F pili between pairs of F+ cells (approximately two to four pili per cell) and by stimulating the formation of colanic acid and curli meshwork. Formation of colanic acid and curli was required after the initial deposition of F-pilus connections to generate a three-dimensional mushroom-type biofilm. In addition, we demonstrated that the conjugative factor of F plasmid, rather than a pilus synthesis function, was involved in curli production during biofilm formation, which promoted cell-surface interactions. Curli played an important role in the maturation process. Microarray experiments were performed to identify the genes involved in curli biosynthesis and regulation. The results suggested that a natural F plasmid was more likely an external activator that indirectly promoted curli production via bacterial regulatory systems (the EnvZ/OmpR two-component regulators and the RpoS and HN-S global regulators). These data provided new insights into the role of a natural F plasmid during the development of E. coli biofilms.

DYNAMIC ASPECTS OF CASCADE-TYPE METABOLIC REGULATION

1995 ◽  
Vol 03 (01) ◽  
pp. 187-196 ◽  
Author(s):  
DOUWE MOLENAAR ◽  
BORIS N. KHOLODENKO ◽  
WALLY C. VAN HEESWIJK ◽  
HANS V. WESTERHOFF
Keyword(s):  
Escherichia Coli ◽  
Glutamine Synthetase ◽  
Metabolic Regulation ◽  
Growth Conditions ◽  
Covalent Modification ◽  
Physiological Signals ◽  
Slow Dynamics ◽  
Evolutionary Advantage ◽  
Ammonia Fixation ◽  
Cascade Type

Cascade-type regulation, where certain enzymes in response to physiological signals modify the activity of other enzymes by covalent modification, is found in many organisms. We study the covalent regulation of glutamine synthetase which is involved in ammonia fixation in the bacterium Escherichia coli. In this paper we pose the question whether this type of regulation of glutamine synthetase has, under certain growth conditions an advantage over other types of regulation, e.g., allosteric regulation. We propose that the relatively slow dynamics of cascade-type regulation has an evolutionary advantage under conditions of fluctuating ammonia concentrations.

scholarly journals Metabolic regulation of Irp gene expression in Escherichia coli K-12

Microbiology ◽  
1997 ◽  
Vol 143 (6) ◽  
pp. 2079-2084 ◽  
Author(s):  
C. F. Chen ◽  
J. Lan ◽  
M. Korovine ◽  
Z. Q. Shao ◽  
L. Tao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Metabolic Regulation ◽  
Expression In Escherichia Coli ◽  
K 12

scholarly journals Effect of Exposure to Chlorhexidine Residues at “During Use” Concentrations on Antimicrobial Susceptibility Profile, Efflux, Conjugative Plasmid Transfer, and Metabolism of Escherichia coli

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
R. Wesgate ◽  
S. Fanning ◽  
Y. Hu ◽  
J.-Y. Maillard
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Metabolic Regulation ◽  
Conjugative Plasmid ◽  
Metabolic Phenotype ◽  
Cross Resistance ◽  
Content Type ◽  
Phenotypic Microarray ◽  
The Impact

ABSTRACT There is no standardized protocol to predict the concentration levels of microbicides that are left on surfaces as a result of the use of these products, and there is no standardized method to predict the potential risk that such levels pose to emerging antibacterial resistance. The ability to distinguish between selection and adaption processes for antimicrobial resistance in bacteria and the impact of different concentrations of microbicide exposure have not been fully investigated to date. This study considers the effect of exposure to a low concentration of chlorhexidine digluconate (CHX) on selected phenotypes of Escherichia coli and relates the findings to the risk of emerging antimicrobial resistance. A concentration of 0.006 mg/ml CHX is a realistic “during use” exposure concentration measured on surfaces. At this concentration, it was possible for CHX-susceptible bacteria to survive, adapt through metabolic alterations, exhibit a transient decrease in antimicrobial susceptibility, and express stable clinical cross-resistance to front-line antibiotics. Efflux activity was present naturally in tested isolates, and it increased in the presence of 0.00005 mg/ml CHX but ceased with 0.002 mg/ml CHX. Phenotypic microarray assays highlighted a difference in metabolic regulation at 0.00005 mg/ml and 0.002 mg/ml CHX; more changes occurred after growth with the latter concentration. Metabolic phenotype changes were observed for substrates involved with the metabolism of some amino acids, cofactors, and secondary metabolites. It was possible for one isolate to continue transferring ampicillin resistance in the presence of 0.00005 mg/ml CHX, whilst 0.002 mg/ml CHX prevented conjugative transfer. In conclusion, E. coli phenotype responses to CHX exposure are concentration dependent, with realistic residual CHX concentrations resulting in stable clinical cross-resistance to antibiotics.

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