scholarly journals Identification of Plasmalogens in the Cytoplasmic Membrane of Bifidobacterium animalis subsp. lactis

2011 ◽  
Vol 78 (3) ◽  
pp. 880-884 ◽  
Author(s):  
Taylor S. Oberg ◽  
Robert E. Ward ◽  
James L. Steele ◽  
Jeff R. Broadbent
Keyword(s):  
Oxidative Stress ◽  
Environmental Stress ◽  
Stress Resistance ◽  
Cell Membranes ◽  
Cytoplasmic Membrane ◽  
Eukaryotic Cell ◽  
Bacterial Membrane ◽  
Membrane Composition ◽  
Content Type ◽  
Bifidobacterium Animalis

ABSTRACTPlasmalogens are ether-linked lipids that may influence oxidative stress resistance of eukaryotic cell membranes. Since bacterial membrane composition can influence environmental stress resistance, we explored the prevalence of plasmalogens in the cytoplasmic membrane ofBifidobacterium animalissubsp.lactis. Results showed plasmalogens are a major component of theB. animalissubsp.lactismembrane.

scholarly journals Pleiotropic Effects of the P5-Type ATPase SpfA on Stress Response Networks Contribute to Virulence in the Pathogenic Mold Aspergillus fumigatus

mBio ◽  
2021 ◽  
Author(s):  
José P. Guirao-Abad ◽  
Martin Weichert ◽  
Ginés Luengo-Gil ◽  
Sarah Sze Wah Wong ◽  
Vishukumar Aimanianda ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Resistance ◽  
Secretory Pathway ◽  
Pathogenic Fungi ◽  
Antifungal Drugs ◽  
Gene Encoding ◽  
Content Type ◽  
Downstream Target ◽  
P Type ◽  
Er Homeostasis

The fungal UPR is an adaptive signaling pathway in the ER that buffers fluctuations in ER stress but also serves as a virulence regulatory hub in species of pathogenic fungi that rely on secretory pathway homeostasis for pathogenicity. This study demonstrates that the gene encoding the ER-localized P5-type ATPase SpfA is a downstream target of the UPR in the pathogenic mold A. fumigatus and that it works together with a second ER-localized P-type ATPase, SrcA, to support ER homeostasis, oxidative stress resistance, susceptibility to antifungal drugs, and virulence of A. fumigatus .

scholarly journals Proline Metabolism IncreaseskatGExpression and Oxidative Stress Resistance in Escherichia coli

2014 ◽  
Vol 197 (3) ◽  
pp. 431-440 ◽  
Author(s):  
Lu Zhang ◽  
James R. Alfano ◽  
Donald F. Becker
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Mutant Strain ◽  
Stress Resistance ◽  
Proline Metabolism ◽  
Wild Type ◽  
Content Type ◽  
Oxidative Stress Resistance ◽  
Proline Utilization

The oxidation ofl-proline to glutamate in Gram-negative bacteria is catalyzed by the proline utilization A (PutA) flavoenzyme, which contains proline dehydrogenase (PRODH) and Δ1-pyrroline-5-carboxylate (P5C) dehydrogenase domains in a single polypeptide. Previous studies have suggested that aside from providing energy, proline metabolism influences oxidative stress resistance in different organisms. To explore this potential role and the mechanism, we characterized the oxidative stress resistance of wild-type andputAmutant strains ofEscherichia coli. Initial stress assays revealed that theputAmutant strain was significantly more sensitive to oxidative stress than the parental wild-type strain. Expression of PutA in theputAmutant strain restored oxidative stress resistance, confirming that depletion of PutA was responsible for the oxidative stress phenotype. Treatment of wild-type cells with proline significantly increased hydroperoxidase I (encoded bykatG) expression and activity. Furthermore, the ΔkatGstrain failed to respond to proline, indicating a critical role for hydroperoxidase I in the mechanism of proline protection. The global regulator OxyR activates the expression ofkatGalong with several other genes involved in oxidative stress defense. In addition tokatG, proline increased the expression ofgrxA(glutaredoxin 1) andtrxC(thioredoxin 2) of the OxyR regulon, implicating OxyR in proline protection. Proline oxidative metabolism was shown to generate hydrogen peroxide, indicating that proline increases oxidative stress tolerance inE. colivia a preadaptive effect involving endogenous hydrogen peroxide production and enhanced catalase-peroxidase activity.

scholarly journals Role of the Filifactor alocis Hypothetical Protein FA519 in Oxidative Stress Resistance

2021 ◽  
Author(s):  
Ezinne Aja ◽  
Arunima Mishra ◽  
Yuetan Dou ◽  
Hansel M. Fletcher
Keyword(s):  
Oxidative Stress ◽  
Periodontal Disease ◽  
Stress Resistance ◽  
Hypothetical Protein ◽  
Content Type ◽  
Genetic Tools ◽  
Oxidative Stress Resistance ◽  
Filifactor Alocis ◽  
Diagnostic Indicator

Filifactor alocis is an emerging member of the periodontal community and is now proposed to be a diagnostic indicator of periodontal disease. However, due to the lack of genetic tools available to study this organism, not much is known about its virulence attributes.

Prevention Against Oxidative Stress of Eukaryotic Cell Membranes by Selenium Compounds of the Rat

2004 ◽  
Vol 1030 (1) ◽  
pp. 458-461 ◽  
Author(s):  
A KYRIAKOPOULOS ◽  
K BUKALIS ◽  
D ROETHLEIN ◽  
B HOPPE ◽  
A GRAEBERT ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Membranes ◽  
Eukaryotic Cell ◽  
Selenium Compounds

scholarly journals Farnesol Induces Hydrogen Peroxide Resistance in Candida albicans Yeast by Inhibiting the Ras-Cyclic AMP Signaling Pathway

2010 ◽  
Vol 9 (4) ◽  
pp. 569-577 ◽  
Author(s):  
Aurélie Deveau ◽  
Amy E. Piispanen ◽  
Angelyca A. Jackson ◽  
Deborah A. Hogan
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Candida Albicans ◽  
Adenylate Cyclase ◽  
Signaling Pathway ◽  
Stress Resistance ◽  
Ros Generation ◽  
Signaling Molecule ◽  
Content Type ◽  
Oxidative Stress Resistance

ABSTRACT Farnesol, a Candida albicans cell-cell signaling molecule that participates in the control of morphology, has an additional role in protection of the fungus against oxidative stress. In this report, we show that although farnesol induces the accumulation of intracellular reactive oxygen species (ROS), ROS generation is not necessary for the induction of catalase (Cat1)-mediated oxidative-stress resistance. Two antioxidants, α-tocopherol and, to a lesser extent, ascorbic acid effectively reduced intracellular ROS generation by farnesol but did not alter farnesol-induced oxidative-stress resistance. Farnesol inhibits the Ras1-adenylate cyclase (Cyr1) signaling pathway to achieve its effects on morphology under hypha-inducing conditions, and we demonstrate that farnesol induces oxidative-stress resistance by a similar mechanism. Strains lacking either Ras1 or Cyr1 no longer exhibited increased protection against hydrogen peroxide upon preincubation with farnesol. While we also observed the previously reported increase in the phosphorylation level of Hog1, a known regulator of oxidative-stress resistance, in the presence of farnesol, the hog1/hog1 mutant did not differ from wild-type strains in terms of farnesol-induced oxidative-stress resistance. Analysis of Hog1 levels and its phosphorylation states in different mutant backgrounds indicated that mutation of the components of the Ras1-adenylate cyclase pathway was sufficient to cause an increase of Hog1 phosphorylation even in the absence of farnesol or other exogenous sources of oxidative stress. This finding indicates the presence of unknown links between these signaling pathways. Our results suggest that farnesol effects on the Ras-adenylate cyclase cascade are responsible for many of the observed activities of this fungal signaling molecule.

scholarly journals The BacterialiprAGene Is Conserved across Enterobacteriaceae, Is Involved in Oxidative Stress Resistance, and Influences Gene Expression in Salmonella enterica Serovar Typhimurium

2016 ◽  
Vol 198 (16) ◽  
pp. 2166-2179 ◽  
Author(s):  
Allison Herman ◽  
Jacquelyn Serfecz ◽  
Alexandra Kinnally ◽  
Kathleen Crosby ◽  
Matthew Youngman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Amino Acids ◽  
Stress Resistance ◽  
Salmonella Enterica ◽  
Phosphotransferase System ◽  
Protein Activity ◽  
Altered Expression ◽  
Content Type ◽  
Oxidative Stress Resistance ◽  
Serovar Typhimurium

ABSTRACTTheiprAgene (formerly known asyaiVor STM0374) is located in a two-gene operon in theSalmonella entericaserovar Typhimurium genome and is associated with altered expression during spaceflight and rotating-wall-vessel culture conditions that increase virulence. However,iprAis uncharacterized in the literature. In this report, we present the first targeted characterization of this gene, which revealed thatiprAis highly conserved acrossEnterobacteriaceae. We found thatS. Typhimurium,Escherichia coli, andEnterobacter cloacaeΔiprAmutant strains display a multi-log-fold increase in oxidative stress resistance that is complemented using a plasmid-borne wild-type (WT) copy of theS. TyphimuriumiprAgene. This observation was also associated with increased catalase activity, increasedS. Typhimurium survival in macrophages, and partial dependence on thekatEgene and full dependence on therpoSgene. Our results indicate that IprA protein activity is sensitive to deletion of the N- and C-terminal 10 amino acids, while a region that includes amino acids 56 to 80 is dispensable for activity. RNA sequencing (RNA-Seq) analysis revealed several genes altered in expression in theS. Typhimurium ΔiprAmutant strain compared to the WT, including those involved in fimbria formation,spvABCD-mediated virulence, ethanolamine utilization, the phosphotransferase system (PTS) transport, and flagellin phase switching from FlgB to FliC (likely a stochastic event) and several genes of hypothetical or putative function.IMPORTANCEOverall, this work reveals that the conservediprAgene measurably influences bacterial biology and highlights the pool of currently uncharacterized genes that are conserved across bacterial genomes. These genes represent potentially useful targets for bacterial engineering, vaccine design, and other possible applications.

scholarly journals Inactivation of the Organic Hydroperoxide Stress Resistance Regulator OhrR Enhances Resistance to Oxidative Stress and Isoniazid in Mycobacterium smegmatis

2014 ◽  
Vol 197 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Sankaralingam Saikolappan ◽  
Kishore Das ◽  
Subramanian Dhandayuthapani
Keyword(s):  
Oxidative Stress ◽  
Mutant Strain ◽  
Stress Resistance ◽  
Mycobacterium Smegmatis ◽  
Cumene Hydroperoxide ◽  
Wild Type ◽  
Mobility Shift ◽  
Organic Hydroperoxide ◽  
Content Type ◽  
Protein Levels

The organic hydroperoxide stress resistance regulator (OhrR) is a MarR type of transcriptional regulator that primarily regulates the expression of organic hydroperoxide reductase (Ohr) in bacteria. In mycobacteria, the genes encoding these proteins exist in only a few species, which include the fast-growing organismMycobacterium smegmatis. To delineate the roles of Ohr and OhrR in defense against oxidative stress inM. smegmatis, strains lacking the expression of these proteins were constructed by deleting theohrRandohrgenes, independently and together, through homologous recombination. The OhrR mutant strain (MSΔohrR) showed severalfold upregulation of Ohr expression, which could be observed at both the transcript and protein levels. Similar upregulation of Ohr expression was also noticed in anM. smegmatiswild-type strain (MSWt) induced with cumene hydroperoxide (CHP) andt-butyl hydroperoxide (t-BHP). The elevated Ohr expression in MSΔohrR correlated with heightened resistance to oxidative stress due to CHP andt-BHP and to inhibitory effects due to the antituberculosis drug isoniazid (INH). Further, this mutant strain exhibited significantly enhanced survival in the intracellular compartments of macrophages. In contrast, the strains lacking either Ohr alone (MSΔohr) or both Ohr and OhrR (MSΔohr-ohrR) displayed limited or no resistance to hydroperoxides and INH. Additionally, these strains showed no significant differences in intracellular survival from the wild type. Electrophoretic mobility shift assays (EMSAs) revealed that the overexpressed and purified OhrR interacts with theohr-ohrRintergenic region with a greater affinity and this interaction is contingent upon the redox state of the OhrR. These findings suggest that Ohr-OhrR is an important peroxide stress response system inM. smegmatis.

scholarly journals Isocitrate Dehydrogenase Is Important for Nitrosative Stress Resistance in Cryptococcus neoformans, but Oxidative Stress Resistance Is Not Dependent on Glucose-6-Phosphate Dehydrogenase

2010 ◽  
Vol 9 (6) ◽  
pp. 971-980 ◽  
Author(s):  
Sarah M. Brown ◽  
Rajendra Upadhya ◽  
James D. Shoemaker ◽  
Jennifer K. Lodge
Keyword(s):  
Oxidative Stress ◽  
Cryptococcus Neoformans ◽  
Stress Resistance ◽  
Isocitrate Dehydrogenase ◽  
Nitrosative Stress ◽  
Stress Sensitivity ◽  
Wild Type ◽  
Oxidative And Nitrosative Stress ◽  
Content Type ◽  
Glucose 6 Phosphate Dehydrogenase

ABSTRACT The opportunistic intracellular fungal pathogen Cryptococcus neoformans depends on many antioxidant and denitrosylating proteins and pathways for virulence in the immunocompromised host. These include the glutathione and thioredoxin pathways, thiol peroxidase, cytochrome c peroxidase, and flavohemoglobin denitrosylase. All of these ultimately depend on NADPH for either catalytic activity or maintenance of a reduced, functional form. The need for NADPH during oxidative stress is well established in many systems, but a role in resistance to nitrosative stress has not been as well characterized. In this study we investigated the roles of two sources of NADPH, glucose-6-phosphate dehydrogenase (Zwf1) and NADP+-dependent isocitrate dehydrogenase (Idp1), in production of NADPH and resistance to oxidative and nitrosative stress. Deletion of ZWF1 in C. neoformans did not result in an oxidative stress sensitivity phenotype or changes in the amount of NADPH produced during oxidative stress compared to those for the wild type. Deletion of IDP1 resulted in greater sensitivity to nitrosative stress than to oxidative stress. The amount of NADPH increased 2-fold over that in the wild type during nitrosative stress, and yet the idp1Δ strain accumulated more mitochondrial damage than the wild type during nitrosative stress. This is the first report of the importance of Idp1 and NADPH for nitrosative stress resistance.

scholarly journals ThePseudomonas stutzeri-Specific Regulatory Noncoding RNA NfiS TargetskatBmRNA Encoding a Catalase Essential for Optimal Oxidative Resistance and Nitrogenase Activity

2019 ◽  
Vol 201 (19) ◽  
Author(s):  
Hongyang Zhang ◽  
Yuhua Zhan ◽  
Yongliang Yan ◽  
Yichao Liu ◽  
Guihua Hu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitrogen Fixation ◽  
Stress Response ◽  
Stress Resistance ◽  
Noncoding Rna ◽  
Oxidative Stress Response ◽  
Nitrogen Fixing ◽  
Base Pairing ◽  
Content Type ◽  
Nitrogenase Activities

ABSTRACTPseudomonas stutzeriA1501 is a versatile nitrogen-fixing bacterium capable of living in diverse environments and coping with various oxidative stresses. NfiS, a regulatory noncoding RNA (ncRNA) involved in the control of nitrogen fixation in A1501, was previously shown to be required for optimal resistance to H2O2; however, the precise role of NfiS and the target genes involved in the oxidative stress response is entirely unknown. In this work, we systematically investigated the NfiS-based mechanisms underlying the response of this bacterium to H2O2at the cellular and molecular levels. A mutant strain carrying a deletion ofnfiSshowed significant downregulation of oxidative stress response genes, especiallykatB, a catalase gene, andoxyR, an essential regulator for transcription of catalase genes. Secondary structure prediction revealed two binding sites in NfiS forkatBmRNA. Complementation experiments using truncatednfiSgenes showed that each of two sites is functional, but not sufficient, for NfiS-mediated regulation of oxidative stress resistance and nitrogenase activities. Microscale thermophoresis assays further indicated direct base pairing betweenkatBmRNA and NfiS at both sites 1 and 2, thus enhancing the half-life of the transcript. We also demonstrated thatkatBexpression is dependent on OxyR and that both OxyR and KatB are essential for optimal oxidative stress resistance and nitrogenase activities. H2O2at low concentrations was detoxified by KatB, leaving O2as a by-product to support nitrogen fixation under O2-insufficient conditions. Moreover, our data suggest that the direct interaction between NfiS andkatBmRNA is a conserved and widespread mechanism amongP. stutzeristrains.IMPORTANCEProtection against oxygen damage is crucial for survival of nitrogen-fixing bacteria due to the extreme oxygen sensitivity of nitrogenase. This work exemplifies how the small ncRNA NfiS coordinates oxidative stress response and nitrogen fixation via base pairing withkatBmRNA andnifKmRNA. Hence, NfiS acts as a molecular link to coordinate the expression of genes involved in oxidative stress response and nitrogen fixation. Our study provides the first insight into the biological functions of NfiS in oxidative stress regulation and adds a new regulation level to the mechanisms that contribute to the oxygen protection of the MoFe nitrogenase.

scholarly journals MntC-Dependent Manganese Transport Is Essential forStaphylococcus aureusOxidative Stress Resistance and Virulence

mSphere ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. e00336-18 ◽  
Author(s):  
Luke D. Handke ◽  
Alexey V. Gribenko ◽  
Yekaterina Timofeyeva ◽  
Ingrid L. Scully ◽  
Annaliesa S. Anderson
Keyword(s):  
Oxidative Stress ◽  
Stress Resistance ◽  
Binding Activity ◽  
Titration Calorimetry ◽  
Sod Activity ◽  
Content Type ◽  
Manganese Ion ◽  
Study Results ◽  
Insertional Inactivation ◽  
Manganese Transport

ABSTRACTStaphylococcus aureusis a human pathogen that has developed several approaches to evade the immune system, including a strategy to resist oxidative killing by phagocytes. This resistance is mediated by production of superoxide dismutase (SOD) enzymes which use manganese as a cofactor.S. aureusencodes two manganese ion transporters, MntABC and MntH, and a possible Nramp family manganese transporter, exemplified byS. aureusN315 SA1432. Their relative contributions to manganese transport have not been well defined in clinically relevant isolates. For this purpose, insertional inactivation mutations were introduced intomntC,mntH, and SA1432 individually and in combination.mntCwas necessary for full resistance to methyl viologen, a compound that generates intracellular free radicals. In contrast, strains with an intactmntHgene had a minimal increase in resistance that was revealed only inmntCstrains, and no change was observed upon mutation of SA1432 in strains lacking bothmntCandmntH. Similarly, MntC alone was required for high cellular SOD activity. In addition,mntCstrains were attenuated in a murine sepsis model. To further link these observations to manganese transport, anS. aureusMntC protein lacking manganese binding activity was designed, expressed, and purified. While circular dichroism experiments demonstrated that the secondary and tertiary structures of this protein were unaltered, a defect in manganese binding was confirmed by isothermal titration calorimetry. Unlike complementation with wild-typemntC, introduction of the manganese-binding defective allele into the chromosome of anmntCstrain did not restore resistance to oxidative stress or virulence. Collectively, these results underscore the importance of MntC-dependent manganese transport inS. aureusoxidative stress resistance and virulence.IMPORTANCEWork outlined in this report demonstrated that MntC-dependent manganese transport is required forS. aureusvirulence. These study results support the model that MntC-specific antibodies elicited by a vaccine have the potential to disruptS. aureusmanganese transport and thus abrogate to its virulence.

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