scholarly journals MerR and ChrR mediate blue light induced photo-oxidative stress response at the transcriptional level in Vibrio cholerae

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Mehmet Tardu ◽  
Selma Bulut ◽  
Ibrahim Halil Kavakli
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Vibrio Cholerae ◽  
Blue Light ◽  
Oxidative Stress Response ◽  
Transcriptional Level

scholarly journals Redox protein OsaR (PA0056) regulates dsbM and the oxidative stress response in Pseudomonas aeruginosa

2020 ◽  
Author(s):  
Yujie Liu ◽  
Yibing Ma ◽  
Zhongqiang Ma ◽  
Xiao Han ◽  
Hang Qi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Stress Response ◽  
Gene Cluster ◽  
Oxidative Stress Response ◽  
Antibiotics Resistance ◽  
Transcriptional Level ◽  
Beta Lactam ◽  
Beta Lactam Antibiotics

Bacteria have evolved distinct molecular mechanisms as a defense against oxidative stress. The foremost regulator of oxidative stress response has been found to be OxyR. However, the molecular details of regulation upstream of OxyR remain largely unknown and need further investigation. Here, we characterize a oxidant stress and antibiotic tolerance regulator, OsaR (PA0056), produced by Pseudomonas aeruginosa. Mutation of osaR increased bacterial tolerance to aminoglycoside and beta-lactam antibiotics, as well as to hydrogen peroxide. Expression of the oxyR regulon genes oxyR, katAB, and ahpBCF was increased in the osaR mutant. However, the OsaR protein does not regulate the oxyR regulon genes through direct binding to their promoters. PA0055, osaR, PA0057 and dsbM are in the same gene cluster, and we provide evidence that expression of these genes involved in oxidant tolerance is controlled by binding of OsaR to intergenic region between osaR and PA0057, which contain two divergent promoters. The gene cluster is also regulated by PA0055 via an indirect effect. We further discovered that OsaR formed intramolecular disulfide bonds when exposed to oxidative stress, resulting in a change of its DNA binding affinity. Taken together, our results indicate that OsaR is inactivated by oxidative stress and plays a role in the tolerance of P. aeruginosa to aminoglycoside and beta-lactam antibiotics. IMPORTANCE As opportunistic pathogen, Pseudomonas aeruginosa can cause serious infections which are hard to eradicate because of antibiotic resistance in immunodeficient patients. We found that OsaR is involved in oxidative stress and antibiotics resistance by regulation of downstream genes via redox state change. Research on factors affecting the transcriptional level of oxyR is very limited, but important since it has implications on antibiotic resistance. In this study, it was found that OsaR can indirectly inhibit transcription of oxyR. In addition the gene cluster composed of PA0055, osaR, PA0057 and dsbM was identified, and the associated regulatory mechanisms and functions were elucidated. Our work not only provides a mechanistic understanding of antibiotic tolerance regulation in P. aeruginosa, but also has significant implications for redox regulation in human pathogens in general.

scholarly journals OxyR2 Modulates OxyR1 Activity and Vibrio cholerae Oxidative Stress Response

2017 ◽  
Vol 85 (4) ◽  
Author(s):  
Hui Wang ◽  
Nawar Naseer ◽  
Yaran Chen ◽  
Anthony Y. Zhu ◽  
Xuewen Kuai ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Vibrio Cholerae ◽  
Diarrheal Disease ◽  
Transcriptional Regulator ◽  
Cysteine Residue ◽  
Oxidative Stress Response ◽  
Human Pathogen ◽  
Content Type ◽  
Low Levels

ABSTRACT Bacteria have developed capacities to deal with different stresses and adapt to different environmental niches. The human pathogen Vibrio cholerae, the causative agent of the severe diarrheal disease cholera, utilizes the transcriptional regulator OxyR to activate genes related to oxidative stress resistance, including peroxiredoxin PrxA, in response to hydrogen peroxide. In this study, we identified another OxyR homolog in V. cholerae, which we named OxyR2, and we renamed the previous OxyR OxyR1. We found that OxyR2 is required to activate its divergently transcribed gene ahpC, encoding an alkylhydroperoxide reductase, independently of H2O2. A conserved cysteine residue in OxyR2 is critical for this function. Mutation of either oxyR2 or ahpC rendered V. cholerae more resistant to H2O2. RNA sequencing analyses indicated that OxyR1-activated oxidative stress-resistant genes were highly expressed in oxyR2 mutants even in the absence of H2O2. Further genetic analyses suggest that OxyR2-activated AhpC modulates OxyR1 activity by maintaining low intracellular concentrations of H2O2. Furthermore, we showed that ΔoxyR2 and ΔahpC mutants were less fit when anaerobically grown bacteria were exposed to low levels of H2O2 or incubated in seawater. These results suggest that OxyR2 and AhpC play important roles in the V. cholerae oxidative stress response.

scholarly journals Environmental Conditions Modulate the Transcriptomic Response of Both Caulobacter crescentus Morphotypes to Cu Stress

2021 ◽  
Vol 9 (6) ◽  
pp. 1116
Author(s):  
Laurens Maertens ◽  
Pauline Cherry ◽  
Françoise Tilquin ◽  
Rob Van Houdt ◽  
Jean-Yves Matroule
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Stress Responses ◽  
Caulobacter Crescentus ◽  
Oxidative Stress Response ◽  
Transport Systems ◽  
Transcriptomic Response ◽  
Swarmer Cell ◽  
Cu Stress ◽  
Cellular Environment

Bacteria encounter elevated copper (Cu) concentrations in multiple environments, varying from mining wastes to antimicrobial applications of copper. As the role of the environment in the bacterial response to Cu ion exposure remains elusive, we used a tagRNA-seq approach to elucidate the disparate responses of two morphotypes of Caulobacter crescentus NA1000 to moderate Cu stress in a complex rich (PYE) medium and a defined poor (M2G) medium. The transcriptome was more responsive in M2G, where we observed an extensive oxidative stress response and reconfiguration of the proteome, as well as the induction of metal resistance clusters. In PYE, little evidence was found for an oxidative stress response, but several transport systems were differentially expressed, and an increased need for histidine was apparent. These results show that the Cu stress response is strongly dependent on the cellular environment. In addition, induction of the extracytoplasmic function sigma factor SigF and its regulon was shared by the Cu stress responses in both media, and its central role was confirmed by the phenotypic screening of a sigF::Tn5 mutant. In both media, stalked cells were more responsive to Cu stress than swarmer cells, and a stronger basal expression of several cell protection systems was noted, indicating that the swarmer cell is inherently more Cu resistant. Our approach also allowed for detecting several new transcription start sites, putatively indicating small regulatory RNAs, and additional levels of Cu-responsive regulation.

scholarly journals Meta-Analysis of Oxidative Transcriptomes in Insects

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 345
Author(s):  
Hidemasa Bono
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Meta Analysis ◽  
Adherens Junction ◽  
Enrichment Analysis ◽  
Oxidative Stress Response ◽  
Insect Species ◽  
Rna Seq ◽  
Manual Curation ◽  
Analysis Workflow

Data accumulation in public databases has resulted in extensive use of meta-analysis, a statistical analysis that combines the results of multiple studies. Oxidative stress occurs when there is an imbalance between free radical activity and antioxidant activity, which can be studied in insects by transcriptome analysis. This study aimed to apply a meta-analysis approach to evaluate insect oxidative transcriptomes using publicly available data. We collected oxidative stress response-related RNA sequencing (RNA-seq) data for a wide variety of insect species, mainly from public gene expression databases, by manual curation. Only RNA-seq data of Drosophila melanogaster were found and were systematically analyzed using a newly developed RNA-seq analysis workflow for species without a reference genome sequence. The results were evaluated by two metric methods to construct a reference dataset for oxidative stress response studies. Many genes were found to be downregulated under oxidative stress and related to organ system process (GO:0003008) and adherens junction organization (GO:0034332) by gene enrichment analysis. A cross-species analysis was also performed. RNA-seq data of Caenorhabditis elegans were curated, since no RNA-seq data of insect species are currently available in public databases. This method, including the workflow developed, represents a powerful tool for deciphering conserved networks in oxidative stress response.

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