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Metronidazole
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Metronidazole has no activity against the aerobic Gram-negative bacteria, Pseudomonas aeruginosa. However, metronidazole was shown to provoke the bacterial SOS response that is activated usually in response to DNA damage (Hocquet and Bertrand, 2014). During the SOS response, error-prone DNA polymerases PolIV and PolV are induced, thereby increasing the pseudomonal spontaneous mutation frequency, which may bring about an antibiotic resistance phenotype. In vitro exposure of P. aeruginosa to metronidazole resulted in increased frequencies of strains resistant to ciprofloxacin and amikacin (Hocquet and Bertrand, 2014).
Biofilm Persisters
Published in Chaminda Jayampath Seneviratne, Microbial Biofilms, 2017
Peng Li, Chaminda Jayampath Seneviratne, Lijian Jin
In addition, the SOS response that mitigates DNA damage is required for hyper-tolerance of E. coli biofilm persisters to fluoroquinolone antibiotics on starvation to specific essential growth nutrients [17]. The starvation-induced biofilm tolerance is partially dependent on a stringent response and independent of the known SOS-related TA modules (TisAB, SymER, DinJ/YafQ and YafNO) [17]. Furthermore, control of antibiotic-induced oxidative stress is a key element in ensuring the survival of bacterial biofilm persisters [18,41]. In C. albicans biofilms, the tolerance of persisters to miconazole is shown to be dependent on the protection against reactive oxygen species (ROS) mediated by superoxide dismutase (SOD) [48]. A recent high-throughput proteomic profiling of Candida biofilm persisters demonstrated that the antifungal tolerance of these survivors is determined by subtle metabolic regulation and activation of stress responses (Figure 8.2). In particular, the Candida biofilm persisters can withstand increased oxidative stress [42].
Biological Activities of Syzygium cumini and Allied Species
Published in K. N. Nair, The Genus Syzygium, 2017
Varughese George, Palpu Pushpangadan
Miyazawa and Hisama (2003) reported the antimutagenic activity of phenylpropanoids from clove (S. aromaticum). Phenylpropanoids that possess antimutagenic activity were isolated from the buds of clove. The isolated compounds suppressed the expression of the umu gene following the induction of the SOS response in S. typhimurium TA1535/pSK1002 treated with various mutagens. The suppressive compounds were mainly localized in the ethyl acetate extract fraction of the processed clove.
Plants growing in Colombia as sources of active ingredients for sunscreens
Published in International Journal of Radiation Biology, 2021
Jorge Luis Fuentes, Diego Armando Villamizar Mantilla, Silvia Juliana Flores González, Luis Alberto Núñez, Elena E. Stashenko
We have recently proposed the SOS Chromotest in Escherichia coli (Quillardet et al. 1982) for bioprospecting of plant antigenotoxic agents against UV radiation with possible application in photoprotection and skin cancer chemoprevention (Fuentes et al. 2017). This assay measures DNA damage by exploiting the inducible DNA replication–cell division coupling system (SOS response) existent in E. coli (Huisman and D´Ari 1981). When E. coli cells are exposed to UV radiation, CPDs are produced, which introduce structural distortions in DNA (Rosenberg and Echols 1990). Since increases of CPDs are an obstacle for E. coli chromosome replication (Courcelle et al. 2003), they induce the SOS response (Huisman and D´Ari 1981). Thus, the SOS response induction quantified by SOS Chromotest is proportional to UV-induced DNA damage (Quillardet and Hofnung 1984). Based on the indicated above, we hypothesized that if induction of erythema and genotoxicity produced by UVB are related, the photoprotection and antigenotoxicity could be also related.
In vitro and in vivo efficacy of Caenorhabditis elegans recombinant antimicrobial protein against Gram-negative bacteria
Published in Biofouling, 2019
Dilawar Ahmad Mir, Krishnaswamy Balamurugan
The proteomic data analysis revealed that the ABF-1 protein affected cell cycle associated proteins (Tables 2 and 3) (RuvB helicase, RecA, mukF, endonuclease-VIII, Rho, rpoC, yajQ, cspA, greA, t1627, dnaB and rcsB). Among these, RuvB is a helicase protein that mediates DNA Holliday junction migration by localizing the denaturation and reannealing and RecA proteins play a role in homologous recombination, promoting synapsis, heteroduplex formation, and strand exchange between homologous DNAs (Iype et al. 1994). The mukF protein is involved in chromosome condensation, which is key step for cell division (Yamazoe et al. 1999). The endonuclease-VIII (NEI) protein acts as a DNA glycosylase that recognizes and removes DNA bases damaged by oxidation or mutagenic agents (Jiang et al. 1997). Collectively, these proteins play an important role in DNA damage, DNA recombination, DNA repair, SOS response and damaged DNA binding (Igarashi and Ishihama 1991; Borukhov et al. 1992; Bae et al. 2000; Skunca et al. 2013).
Apyrase decreases phage induction and Shiga toxin release from E. coli O157:H7 and has a protective effect during infection
Published in Gut Microbes, 2022
Ida Arvidsson, Ashmita Tontanahal, Karl Johansson, Ann-Charlotte Kristoffersson, Sára Kellnerová, Michael Berger, Ulrich Dobrindt, Diana Karpman
Stx is encoded by a lambdoid prophage integrated in the bacterial chromosome (reviewed by Rodríguez-Rubio, et al.).9 The expression of the prophage late genes, including the stx determinant, is under the control of the repressor CI.10,11 When the SOS response is activated, by various physical or chemical stimuli, as well as by quorum sensing,12 the bacterial protein RecA is polymerized and promotes auto-cleavage of the phage repressor CI, and the phage enters the lytic growth cycle inducing stx gene transcription.13 RecA thereby induces Stx bacteriophage activation ultimately leading to bacterial expression and release of Stx.14