N-acetylcysteine blocks SOS induction and mutagenesis produced by fluoroquinolones in Escherichia coli

2019 ◽  
Vol 74 (8) ◽  
pp. 2188-2196 ◽  
Author(s):  
Ana I Rodríguez-Rosado ◽  
Estela Ynés Valencia ◽  
Alexandro Rodríguez-Rojas ◽  
Coloma Costas ◽  
Rodrigo S Galhardo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sos Response ◽  
Mutagenic Effect ◽  
Coli Strain ◽  
New Drugs ◽  
Ros Production ◽  
Sos Mutagenesis ◽  
Sos Induction ◽  
Key Factor ◽  
Bacterial Mutagenesis

AbstractBackgroundFluoroquinolones such as ciprofloxacin induce the mutagenic SOS response and increase the levels of intracellular reactive oxygen species (ROS). Both the SOS response and ROS increase bacterial mutagenesis, fuelling the emergence of resistant mutants during antibiotic treatment. Recently, there has been growing interest in developing new drugs able to diminish the mutagenic effect of antibiotics by modulating ROS production and the SOS response.ObjectivesTo test whether physiological concentrations of N-acetylcysteine, a clinically safe antioxidant drug currently used in human therapy, is able to reduce ROS production, SOS induction and mutagenesis in ciprofloxacin-treated bacteria without affecting antibiotic activity.MethodsThe Escherichia coli strain IBDS1 and its isogenic mutant deprived of SOS mutagenesis (TLS−) were treated with different concentrations of ciprofloxacin, N-acetylcysteine or both drugs in combination. Relevant parameters such as MICs, growth rates, ROS production, SOS induction, filamentation and antibiotic-induced mutation rates were evaluated.ResultsTreatment with N-acetylcysteine reduced intracellular ROS levels (by ∼40%), as well as SOS induction (by up to 75%) and bacterial filamentation caused by subinhibitory concentrations of ciprofloxacin, without affecting ciprofloxacin antibacterial activity. Remarkably, N-acetylcysteine completely abolished SOS-mediated mutagenesis.ConclusionsCollectively, our data strongly support the notion that ROS are a key factor in antibiotic-induced SOS mutagenesis and open the possibility of using N-acetylcysteine in combination with antibiotic therapy to hinder the development of antibiotic resistance.

Mutagenesis and More: umuDC and the Escherichia coli SOS Response

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1599-1610 ◽  
Author(s):  
Bradley T Smith ◽  
Graham C Walker
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Cellular Response ◽  
Sos Response ◽  
Posttranslational Regulation ◽  
E Coli ◽  
Sos Mutagenesis ◽  
Induced Mutagenesis ◽  
Mechanistic Basis ◽  
Increase Cell Survival

Abstract The cellular response to DNA damage that has been most extensively studied is the SOS response of Escherichia coli. Analyses of the SOS response have led to new insights into the transcriptional and posttranslational regulation of processes that increase cell survival after DNA damage as well as insights into DNA-damage-induced mutagenesis, i.e., SOS mutagenesis. SOS mutagenesis requires the recA and umuDC gene products and has as its mechanistic basis the alteration of DNA polymerase III such that it becomes capable of replicating DNA containing miscoding and noncoding lesions. Ongoing investigations of the mechanisms underlying SOS mutagenesis, as well as recent observations suggesting that the umuDC operon may have a role in the regulation of the E. coli cell cycle after DNA damage has occurred, are discussed.

scholarly journals Inactivation of Umuc Protein Significantly Reduces Resistance to Ciprofloxacin and SOS Mutagenesis in Escherichia coli Mutants Harboring Intact Umud Gene

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Razieh Pourahmad Jaktaji ◽  
Sayedeh Marzieh Nourbakhsh Rezaei
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Genetic Background ◽  
Pcr Amplification ◽  
Sos Response ◽  
Rpob Gene ◽  
Dilution Method ◽  
E Coli ◽  
Sos Mutagenesis ◽  
Dna Polymerase V

Background: Ciprofloxacin induces SOS response and mutagenesis by activation of UmuD’2C (DNA polymerase V) and DinB (DNA polymerase IV) in Escherichia coli, leading to antibiotic resistance during therapy. Inactivation of DNA polymerase V can result in the inhibition of mutagenesis in E. coli. Objectives: The aim of this research was to investigate the effect of UmuC inactivation on resistance to ciprofloxacin and SOS mutagenesis in E. coli mutants. Methods: Ciprofloxacin-resistant mutants were produced in a umuC- genetic background in the presence of increasing concentrations of ciprofloxacin. The minimum inhibitory concentration of umuC-mutants was measured by broth dilution method. Alterations in the rifampin resistance-determing region of rpoB gene were assessed by PCR amplification and DNA sequencing. The expression of SOS genes was measured by quantitative real-time PCR assay. Results: Results showed that despite the induction of SOS response (overexpression of recA, dinB, and umuD genes) following exposure to ciprofloxacin in E. coliumuC mutants, resistance to ciprofloxacin and SOS mutagenesis significantly decreased. However, rifampicin-resistant clones emerged in this genetic background. One of these clones showed mutations in the rifampicin resistance-determining region of rpoB (cluster II). The low mutation frequency of E. coli might be associated with the presence and overexpression of umuD gene, which could somehow limit the activity of DinB, the location and type of mutations in the β subunit of RNA polymerase. Conclusions: In conclusion, for increasing the efficiency of ciprofloxacin against Gram-negative bacteria, use of an inhibitor of umuC, along with ciprofloxacin, would be helpful.

scholarly journals Effect of Subinhibitory Concentrations of Antibiotics on Intrachromosomal Homologous Recombination in Escherichia coli

2009 ◽  
Vol 53 (8) ◽  
pp. 3411-3415 ◽  
Author(s):  
Elena López ◽  
Jesús Blázquez
Keyword(s):  
Escherichia Coli ◽  
Homologous Recombination ◽  
Dna Sequences ◽  
Sos Response ◽  
E Coli ◽  
Homologous Sequences ◽  
Sos Induction ◽  
Quinolone Antibiotics ◽  
Subinhibitory Concentrations ◽  
Sublethal Concentrations

ABSTRACT Subinhibitory concentrations of some antibiotics, such as fluoroquinolones, have been reported to stimulate mutation and, consequently, bacterial adaptation to different stresses, including antibiotic pressure. In Escherichia coli, this stimulation is mediated by alternative DNA polymerases induced via the SOS response. Sublethal concentrations of the fluoroquinolone ciprofloxacin have been shown to stimulate recombination between divergent sequences in E. coli. However, the effect of ciprofloxacin on recombination between homologous sequences and its SOS dependence have not been studied. Moreover, the possible effects of other antibiotics on homologous recombination remain untested. The aim of this work was to study the effects of sublethal concentrations of ciprofloxacin and 10 additional antibiotics, including different molecular families with different molecular targets, on the rate of homologous recombination of DNA in E. coli. The antibiotics tested were ciprofloxacin, ampicillin, ceftazidime, imipenem, chloramphenicol, tetracycline, gentamicin, rifampin (rifampicin), trimethoprim, fosfomycin, and colistin. Our results indicate that only ciprofloxacin consistently stimulates the intrachromosomal recombinogenic capability of homologous sequences in E. coli. The ciprofloxacin-based stimulation occurs at concentrations and times that apparently do not dramatically compromise the viability of the whole population, and it is dependent on RecA and partially dependent on SOS induction. One of the main findings of this work is that, apart from quinolone antibiotics, none of the most used antibiotics, including trimethoprim (a known inducer of the SOS response), has a clear side effect on homologous recombination in E. coli. In addition to the already described effects of some antibiotics on mutagenicity, DNA transfer, and genetic transformability in naturally competent species, the effect of increasing intrachromosomal recombination of homologous DNA sequences can be uniquely ascribed to fluoroquinolones, at least for E. coli.

scholarly journals No Genetic Barriers between Salmonella enterica Serovar Typhimurium and Escherichia coli in SOS-Induced Mismatch Repair-Deficient Cells

2000 ◽  
Vol 182 (20) ◽  
pp. 5922-5924 ◽  
Author(s):  
Ivan Matic ◽  
François Taddei ◽  
Miroslav Radman
Keyword(s):  
Escherichia Coli ◽  
Mismatch Repair ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Sos Response ◽  
Sos Induction ◽  
Serovar Typhimurium ◽  
Genetic Barriers

ABSTRACT Conjugational crosses trigger SOS induction in Escherichia coli F− cells mated with Salmonella enterica serovar Typhimurium Hfr donors. Using an epigenetic indicator of SOS induction, we showed that a strong SOS response occurring in a subpopulation of mated mismatch repair-deficient cells totally abolishes genetic barriers between these two genera.

scholarly journals The Crohn’s disease-associated Escherichia coli strain LF82 rely on SOS and stringent responses to survive, multiply and tolerate antibiotics within macrophages

2019 ◽  
Author(s):  
Gaëlle Demarre ◽  
Victoria Prudent ◽  
Hanna Schenk ◽  
Emilie Rousseau ◽  
Marie-Agnes Bringer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Single Cell Analysis ◽  
Stringent Response ◽  
Coli Strain ◽  
Genetic Dissection ◽  
Growth Status ◽  
Sos Induction ◽  
Cycle Regulation

AbstractAdherent Invasive Escherichia coli (AIEC) strains recovered from Crohn's disease lesions survive and multiply within macrophages. A reference strain for this pathovar, AIEC LF82, forms microcolonies within phagolysosomes, an environment that prevents commensal E. coli multiplication. Little is known about the LF82 intracellular growth status, and signals leading to macrophage intra-vacuolar multiplication. We used single-cell analysis, genetic dissection and mathematical models to monitor the growth status and cell cycle regulation of intracellular LF82. We found that within macrophages, bacteria may replicate or undergo non-growing phenotypic switches. This switch results from stringent response firing immediately after uptake by macrophages or at later stages, following genotoxic damage and SOS induction during intracellular replication. Importantly, non-growers resist treatment with various antibiotics. Thus, intracellular challenges induce AIEC LF82 phenotypic heterogeneity and non-growing bacteria that could provide a reservoir for antibiotic-tolerant bacteria responsible for relapsing infections.

Induction of SOS response in Escherichia coli strain PQ37 by 16 chemical compounds and human urine extracts

Mutagenesis ◽  
1989 ◽  
Vol 4 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Paola Venier ◽  
Roberta Montini ◽  
Mauro Zordan ◽  
Erminio Clonfero ◽  
Maurizio Paleologo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Human Urine ◽  
Chemical Compounds ◽  
Sos Response ◽  
Coli Strain

scholarly journals The ε Subunit of DNA Polymerase III Is Involved in the Nalidixic Acid-Induced SOS Response in Escherichia coli

2008 ◽  
Vol 190 (15) ◽  
pp. 5239-5247 ◽  
Author(s):  
Jennifer Reineke Pohlhaus ◽  
David T. Long ◽  
Erin O'Reilly ◽  
Kenneth N. Kreuzer
Keyword(s):  
Escherichia Coli ◽  
Nalidixic Acid ◽  
Dna Polymerase ◽  
Sos Response ◽  
Dependent Manner ◽  
Dna Polymerase Iii ◽  
Dna Breaks ◽  
Sos Induction ◽  
Polymerase Iii ◽  
Cleavage Complex

ABSTRACT Quinolone antibacterial drugs such as nalidixic acid target DNA gyrase in Escherichia coli. These inhibitors bind to and stabilize a normally transient covalent protein-DNA intermediate in the gyrase reaction cycle, referred to as the cleavage complex. Stabilization of the cleavage complex is necessary but not sufficient for cell killing—cytotoxicity apparently results from the conversion of cleavage complexes into overt DNA breaks by an as-yet-unknown mechanism(s). Quinolone treatment induces the bacterial SOS response in a RecBC-dependent manner, arguing that cleavage complexes are somehow converted into double-stranded breaks. However, the only proteins known to be required for SOS induction by nalidixic acid are RecA and RecBC. In hopes of identifying additional proteins involved in the cytotoxic response to nalidixic acid, we screened for E. coli mutants specifically deficient in SOS induction upon nalidixic acid treatment by using a dinD::lacZ reporter construct. From a collection of SOS partially constitutive mutants with disruptions of 47 different genes, we found that dnaQ insertion mutants are specifically deficient in the SOS response to nalidixic acid. dnaQ encodes DNA polymerase III ε subunit, the proofreading subunit of the replicative polymerase. The deficient response to nalidixic acid was rescued by the presence of the wild-type dnaQ gene, confirming involvement of the ε subunit. To further characterize the SOS deficiency of dnaQ mutants, we analyzed the expression of several additional SOS genes in response to nalidixic acid using real-time PCR. A subset of SOS genes lost their response to nalidixic acid in the dnaQ mutant strain, while two tested SOS genes (recA and recN) continued to exhibit induction. These results argue that the replication complex plays a role in modulating the SOS response to nalidixic acid and that the response is more complex than a simple on/off switch.

scholarly journals Identification of genes involved in low aminoglycoside-induced SOS response in Vibrio cholerae: a role for transcription stalling and Mfd helicase

2013 ◽  
Vol 42 (4) ◽  
pp. 2366-2379 ◽  
Author(s):  
Zeynep Baharoglu ◽  
Anamaria Babosan ◽  
Didier Mazel
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Vibrio Cholerae ◽  
Sos Response ◽  
Genetic Screen ◽  
Dna Lesions ◽  
Gene Overexpression ◽  
Sos Induction ◽  
Complex Reconstruction ◽  
Oxidized Guanine

Abstract Sub-inhibitory concentrations (sub-MIC) of antibiotics play a very important role in selection and development of resistances. Unlike Escherichia coli, Vibrio cholerae induces its SOS response in presence of sub-MIC aminoglycosides. A role for oxidized guanine residues was observed, but the mechanisms of this induction remained unclear. To select for V. cholerae mutants that do not induce low aminoglycoside-mediated SOS induction, we developed a genetic screen that renders induction of SOS lethal. We identified genes involved in this pathway using two strategies, inactivation by transposition and gene overexpression. Interestingly, we obtained mutants inactivated for the expression of proteins known to destabilize the RNA polymerase complex. Reconstruction of the corresponding mutants confirmed their specific involvement in induction of SOS by low aminoglycoside concentrations. We propose that DNA lesions formed on aminoglycoside treatment are repaired through the formation of single-stranded DNA intermediates, inducing SOS. Inactivation of functions that dislodge RNA polymerase leads to prolonged stalling on these lesions, which hampers SOS induction and repair and reduces viability under antibiotic stress. The importance of these mechanisms is illustrated by a reduction of aminoglycoside sub-MIC. Our results point to a central role for transcription blocking at DNA lesions in SOS induction, so far underestimated.

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