scholarly journals 3-phenylpropionate catabolism and the Escherichia coli oxidative stress response

2005 ◽  
Vol 156 (3) ◽  
pp. 312-321 ◽  
Author(s):  
Evelyne Turlin ◽  
Odile Sismeiro ◽  
Jean Pierre Le Caer ◽  
Valérie Labas ◽  
Antoine Danchin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Stress Response ◽  
Oxidative Stress Response

scholarly journals Escherichia coli K-12 YfgF is an anaerobic cyclic di-GMP phosphodiesterase with roles in cell surface remodelling and the oxidative stress response

Microbiology ◽  
2010 ◽  
Vol 156 (9) ◽  
pp. 2873-2886 ◽  
Author(s):  
Melissa M. Lacey ◽  
Jonathan D. Partridge ◽  
Jeffrey Green
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Stress Response ◽  
Cell Surface ◽  
Regulatory Networks ◽  
Oxidative Stress Response ◽  
Cyclase Activity ◽  
Diguanylate Cyclase ◽  
Phosphodiesterase Activity ◽  
K 12

The Escherichia coli K-12 yfgF gene encodes a protein with domains associated with cyclic di-GMP signalling: GGDEF (associated with diguanylate cyclase activity) and EAL (associated with cyclic di-GMP phosphodiesterase activity). Here, it is shown that yfgF is expressed under anaerobic conditions from a class II FNR (regulator of fumarate and nitrate reduction)-dependent promoter. Anaerobic expression of yfgF is greatest in stationary phase, and in cultures grown at 28 °C, suggesting that low growth rates promote yfgF expression. Mutation of yfgF resulted in altered cell surface properties and enhanced sensitivity when anaerobic cultures were exposed to peroxides. The purified YfgF GGDEF-EAL (YfgFGE) and EAL (YfgFE) domains possessed cyclic di-GMP-specific phosphodiesterase activity, but lacked diguanylate cyclase activity. However, the catalytically inactive GGDEF domain was required for YfgFGE dimerization and enhanced cyclic di-GMP phosphodiesterase activity in the presence of physiological concentrations of Mg2+. The cyclic di-GMP phosphodiesterase activity of YfgFGE and YfgFE was inhibited by the product of the reaction, 5′-phosphoguanylyl-(3′–5′)-guanosine (pGpG). Thus, it is shown that the yfgF gene encodes an anaerobic cyclic di-GMP phosphodiesterase that is involved in remodelling the cell surface of E. coli K-12 and in the response to peroxide shock, with implications for integrating three global regulatory networks, i.e. oxygen regulation, cyclic di-GMP signalling and the oxidative stress response.

scholarly journals Increasing the Oxidative Stress Response Allows Escherichia coli To Overcome Inhibitory Effects of Condensed Tannins

2003 ◽  
Vol 69 (6) ◽  
pp. 3406-3411 ◽  
Author(s):  
Alexandra H. Smith ◽  
James A. Imlay ◽  
Roderick I. Mackie
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Stress Response ◽  
Condensed Tannins ◽  
Resistant Mutant ◽  
Inhibitory Effect ◽  
Oxidative Stress Response ◽  
Inhibitory Effects ◽  
Acacia Mearnsii ◽  
E Coli

ABSTRACT Tannins are plant-derived polyphenols with antimicrobial effects. The mechanism of tannin toxicity towards Escherichia coli was determined by using an extract from Acacia mearnsii (Black wattle) as a source of condensed tannins (proanthocyanidins). E. coli growth was inhibited by tannins only when tannins were exposed to oxygen. Tannins auto-oxidize, and substantial hydrogen peroxide was generated when they were added to aerobic media. The addition of exogenous catalase permitted growth in tannin medium. E. coli mutants that lacked HPI, the major catalase, were especially sensitive to tannins, while oxyR mutants that constitutively overexpress antioxidant enzymes were resistant. A tannin-resistant mutant was isolated in which a promoter-region point mutation increased the level of HPI by 10-fold. Our results indicate that wattle condensed tannins are toxic to E. coli in aerobic medium primarily because they generate H2O2. The oxidative stress response helps E. coli strains to overcome their inhibitory effect.

scholarly journals Cyclic AMP Regulates Bacterial Persistence through Repression of the Oxidative Stress Response and SOS-Dependent DNA Repair in Uropathogenic Escherichia coli

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Roberto C. Molina-Quiroz ◽  
Cecilia Silva-Valenzuela ◽  
Jennifer Brewster ◽  
Eduardo Castro-Nallar ◽  
Stuart B. Levy ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Dna Repair ◽  
Stress Response ◽  
Cyclic Amp ◽  
Oxidative Stress Response ◽  
Negative Regulator ◽  
Bacterial Persistence ◽  
Persister Cells ◽  
E Coli

ABSTRACTBacterial persistence is a transient, nonheritable physiological state that provides tolerance to bactericidal antibiotics. The stringent response, toxin-antitoxin modules, and stochastic processes, among other mechanisms, play roles in this phenomenon. How persistence is regulated is relatively ill defined. Here we show that cyclic AMP, a global regulator of carbon catabolism and other core processes, is a negative regulator of bacterial persistence in uropathogenicEscherichia coli, as measured by survival after exposure to a β-lactam antibiotic. This phenotype is regulated by a set of genes leading to an oxidative stress response and SOS-dependent DNA repair. Thus, persister cells tolerant to cell wall-acting antibiotics must cope with oxidative stress and DNA damage and these processes are regulated by cyclic AMP in uropathogenicE. coli.IMPORTANCEBacterial persister cells are important in relapsing infections in patients treated with antibiotics and also in the emergence of antibiotic resistance. Our results show that in uropathogenicE. coli, the second messenger cyclic AMP negatively regulates persister cell formation, since in its absence much more persister cells form that are tolerant to β-lactams antibiotics. We reveal the mechanism to be decreased levels of reactive oxygen species, specifically hydroxyl radicals, and SOS-dependent DNA repair. Our findings suggest that the oxidative stress response and DNA repair are relevant pathways to target in the design of persister-specific antibiotic compounds.

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