Changes of enzyme activities related to oxidative stress in rice plants inoculated with random mutants of a Pseudomonas fluorescens strain able to improve plant fitness upon biotic and abiotic conditions

2017 ◽  
Vol 44 (11) ◽  
pp. 1063 ◽  
Author(s):  
Jose A. Lucas ◽  
Ana Garcia-Villaraco Velasco ◽  
Beatriz Ramos ◽  
Francisco J. Gutierrez-Mañero
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Fluorescens ◽  
Enzyme Activities ◽  
Efflux Pump ◽  
Redox Balance ◽  
Wild Type ◽  
Biotic And Abiotic Stress ◽  
Tn5 Transposon ◽  
Biological Tests ◽  
Heavy Metal Efflux

The Pseudomonas fluorescens strain used in this work (Aur 6) has demonstrated its ability to improve fitness of different plant species upon biotic and abiotic stress conditions. Random mutants of this strain were constructed with the Tn5 transposon technology, and biological tests to evaluate loss of salt protection were conducted with all the mutants (104 mutants) on rice seedlings. Mutant 33 showed an evident reduction in its ability to protect plants upon salt stress challenge, whereas mutant 19 was more effective than the wild type. Enzymes related with oxidative stress were studied in both mutants and wild type. Enzyme activities were decreased with mutant 33 with regard to wild type, whereas mutant 19 did not produce important changes suggesting involvement of redox balance associated to the observed modifications in these antioxidant enzymes as one of the probable mechanisms used by these strains. Data of malondialdehyde (MDA) were consistent with this fact. Mutants also affected accumulation of proline, the most common osmolyte in plants. A second experiment to evaluate the ability of both mutants and wild type to stimulate growth on tomato plants was conducted, as this feature was previously demonstrated by wild type. Similar results were obtained in growth of both species, suggesting that mutations of both mutants are related with the capacities of the wild type to stimulate growth. To reveal mutated genes, both mutants were mapped. Three mutated genes were found in mutant 33. A gene related with a general secretion pathway protein D, a gene related with a putative two-component system sensor kinase (ColS), and a gene related with flagellar motor switch protein (FliG). In mutant 19, two mutated genes were found. One gene related with heavy metal efflux pump Czca family, and other gene of 16s rRNA.

Role of thylakoid Ndh complex and peroxidase in the protection against photo-oxidative stress: fluorescence and enzyme activities in wild-type and ndhF-deficient tobacco

2004 ◽  
Vol 122 (4) ◽  
pp. 443-452 ◽  
Author(s):  
Mercedes Martin ◽  
Leonardo M. Casano ◽  
Jose M. Zapata ◽  
Alfredo Guera ◽  
Eva M. del Campo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Enzyme Activities ◽  
Wild Type

scholarly journals Manganese Homeostasis in Group A Streptococcus Is Critical for Resistance to Oxidative Stress and Virulence

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Andrew G. Turner ◽  
Cheryl-lynn Y. Ong ◽  
Christine M. Gillen ◽  
Mark R. Davies ◽  
Nicholas P. West ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Transition Metal ◽  
Metal Ion ◽  
Double Mutant ◽  
Efflux Pump ◽  
Group A Streptococcus ◽  
Wild Type ◽  
Group A

ABSTRACT Streptococcus pyogenes (group A Streptococcus [GAS]) is an obligate human pathogen responsible for a spectrum of human disease states. Metallobiology of human pathogens is revealing the fundamental role of metals in both nutritional immunity leading to pathogen starvation and metal poisoning of pathogens by innate immune cells. Spy0980 (MntE) is a paralog of the GAS zinc efflux pump CzcD. Through use of an isogenic mntE deletion mutant in the GAS serotype M1T1 strain 5448, we have elucidated that MntE is a manganese-specific efflux pump required for GAS virulence. The 5448ΔmntE mutant had significantly lower survival following infection of human neutrophils than did the 5448 wild type and the complemented mutant (5448ΔmntE::mntE). Manganese homeostasis may provide protection against oxidative stress, explaining the observed ex vivo reduction in virulence. In the presence of manganese and hydrogen peroxide, 5448ΔmntE mutant exhibits significantly lower survival than wild-type 5448 and the complemented mutant. We hypothesize that MntE, by maintaining homeostatic control of cytoplasmic manganese, ensures that the peroxide response repressor PerR is optimally poised to respond to hydrogen peroxide stress. Creation of a 5448ΔmntE-ΔperR double mutant rescued the oxidative stress resistance of the double mutant to wild-type levels in the presence of manganese and hydrogen peroxide. This work elucidates the mechanism for manganese toxicity within GAS and the crucial role of manganese homeostasis in maintaining GAS virulence. IMPORTANCE Manganese is traditionally viewed as a beneficial metal ion to bacteria, and it is also established that most bacteria can tolerate high concentrations of this transition metal. In this work, we show that in group A Streptococcus, mutation of the mntE locus, which encodes a transport protein of the cation diffusion facilitator (CDF) family, results in accumulation of manganese and sensitivity to this transition metal ion. The toxicity of manganese is indirect and is the result of a failure of the PerR regulator to respond to oxidative stress in the presence of high intracellular manganese concentrations. These results highlight the importance of MntE in manganese homeostasis and maintenance of an optimal manganese/iron ratio in GAS and the impact of manganese on resistance to oxidative stress and virulence.

scholarly journals Analysis of the oxidative stress regulon identifies soxS as a genetic target for resistance reversal in multi-drug resistant Klebsiella pneumoniae

2020 ◽  
Author(s):  
João Anes ◽  
Katherine Dever ◽  
Athmanya Eshwar ◽  
Scott Nguyen ◽  
Yu Cao ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Klebsiella Pneumoniae ◽  
Efflux Pump ◽  
Similar Data ◽  
Drug Resistant ◽  
Rna Seq ◽  
Wild Type ◽  
Knock Out ◽  
Global Regulators

AbstractIn bacteria, the defense system deployd to counter oxidative stress is orchestrated by three transcriptional factors – SoxS, SoxR, and OxyR. Although the regulon that these factors control is known in many bacteria, similar data is not available for Klebsiella pneumoniae. To address this data gap, oxidative stress was artificially induced in K. pneumoniae MGH 78578 using paraquat and the corresponding oxidative stress regulon recorded using RNA-seq. The soxS gene was significantly induced during oxidative stress and a knock-out mutant was constructed, to explore its functionality. The wild-type and mutant were grown in the presence of paraquat and subjected to RNA-seq to elucidate the soxS regulon in K. pneumoniae MGH78578. Genes that are commonly regulated both in the oxidative stress regulon and soxS regulon were identified and denoted as the ‘oxidative SoxS regulon’ – these included a stringent group of genes specifically regulated by SoxS. Efflux pump encoding genes such as acrAB-tolC, acrE, and global regulators such as marRAB were identified as part of this regulon. Consequently, the isogenic soxS mutant was found to exhibit a reduction in the minimum bactericidal concentration against tetracycline compared to that of the wild type. Impaired efflux activity, allowing tetracycline to be accumulated in the cytoplasm to bactericidal levels, was further evaluated using a tetraphenylphosphonium (TPP+) accumulation assay. The soxS mutant was also susceptible to tetracycline in vivo, in a zebrafish embryo model. We conclude that the soxS gene could be considered as a genetic target against which an inhibitor could be developed in the future and used in combinatorial therapy with tetracycline to combat infections associated with multi-drug resistant K. pneumoniae.

scholarly journals Modulation of Hippocampal Antioxidant Defense System in Chronically Stressed Rats by Lithium

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Nataša Popović ◽  
Vesna Stojiljković ◽  
Snežana Pejić ◽  
Ana Todorović ◽  
Ivan Pavlović ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Superoxide Dismutase ◽  
Enzyme Activities ◽  
Manganese Superoxide Dismutase ◽  
Lithium Treatment ◽  
Antioxidant Defense System ◽  
Redox Balance ◽  
Preclinical Research ◽  
Protein Levels

This study examined the effects of lithium on gene expression and activity of the antioxidant enzymes copper zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in the hippocampus of chronically stressed rats. In addition, we examined the effects of lithium on anxiety behaviors, hippocampal concentrations of dopamine (DA) and malondialdehyde (MDA), protein levels of brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH), dopamine transporter (DAT), and catechol-O-methyltransferase (COMT), as well as activity of monoamine oxidase (MAO) in chronically stressed rats. The investigated parameters were quantified by real-time RT-PCR, Western blot analyses, and assays of enzyme activities. We found that lithium did not change gene expression of SOD1, CAT, GPx, and GR but decreased gene expression of SOD2 in chronically stressed rats. A very important result in this study was that lithium treatment decreased the enzyme activities of SOD1 and SOD2 but increased the enzyme activities of GPx and GR in stress condition, which indicates the control of redox balance. The reduced concentration of MDA confirms this. In addition, we found that lithium treatment decreased high protein levels of BDNF and DAT in chronically stressed rats to the level found in unstressed animals. Also, lithium treatment increased the expression of TH but decreased the enzyme activity of MAO B, which contributed to the increase of hippocampal concentration of DA in chronically stressed rats to the level of unstressed animals. Finally, lithium treatment in animals exposed to chronic stress increased the time spent in open arms. Lithium-induced modulation of hippocampal antioxidant status and attenuation of oxidative stress stabilized behavior in animals with high anxiety index. In addition, reduced oxidative stress was followed by the changes of both turnover of DA and levels of BDNF protein in chronically stressed rats treated with lithium. These findings may be important in preclinical research of the effects of lithium on oxidative stress level in pathological conditions.

scholarly journals Age-Associated Insolubility of Parkin in Human Midbrain is Linked to Redox Balance and Sequestration of Reactive Dopamine Metabolites

2020 ◽  
Author(s):  
Jacqueline M. Tokarew ◽  
Daniel N. El-Kodsi ◽  
Nathalie A. Lengacher ◽  
Travis K. Fehr ◽  
Angela P. Nguyen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Human Brain ◽  
Posttranslational Modifications ◽  
Redox Balance ◽  
Redox Activity ◽  
Wild Type ◽  
Dopamine Metabolites ◽  
Human Control ◽  
Adult Human ◽  
Melanin Formation

AbstractThe mechanisms by which parkin protects the adult human brain from Parkinson disease remain incompletely understood. We hypothesized that parkin cysteines participate in redox reactions, which are reflected in its posttranslational modifications. We found that in human control brain, including the S. nigra, parkin is largely insoluble after age 40 years, which is linked to its oxidation, e.g., at Cys95 and Cys253. In mice, oxidative stress increases posttranslational modifications at parkin cysteines and reduces its solubility. Oxidation of recombinant parkin also promotes insolubility and aggregate formation, but in parallel, lowers hydrogen peroxide (H2O2). This thiol-based redox activity is diminished by parkin point mutants, e.g., p.C431F and p.G328E. Intriguingly, in parkin-deficient human brain H2O2 concentrations are elevated. In prkn-null mice, H2O2 levels are dysregulated under oxidative stress conditions, such as acutely by MPTP-toxin exposure or chronically due to a second genetic hit. In dopamine toxicity studies, wild-type parkin, but not disease-linked mutants, protects human dopaminergic M17 cells, in part through lowering H2O2. Parkin also neutralizes reactive, electrophilic dopamine metabolites via adduct formation, which occurs foremost at primate-specific Cys95. Further, wild-type but not p.C95A-mutant parkin augments melanin formation. In sections of normal, adult human midbrain, parkin specifically co-localizes with neuromelanin pigment, frequently within LAMP-3/CD63+ lysosomes. We conclude that oxidative modifications of parkin cysteines are associated with protective outcomes, which include the reduction of H2O2, conjugation of reactive dopamine metabolites, sequestration of radicals within insoluble aggregates, and increased melanin formation. The loss of these redox effects may augment oxidative stress in dopamine producing neurons of mutant PRKN allele carriers, thereby contributing to neurodegeneration.

scholarly journals The ABC-Type Efflux Pump MacAB Protects Salmonella enterica serovar Typhimurium from Oxidative Stress

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Lydia M. Bogomolnaya ◽  
Katharine D. Andrews ◽  
Marissa Talamantes ◽  
Aimee Maple ◽  
Yury Ragoza ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Salmonella Enterica ◽  
Efflux Pump ◽  
Wild Type ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Drug Efflux Pump

ABSTRACTMultidrug efflux pumps are integral membrane proteins known to actively excrete antibiotics. The macrolide-specific pump MacAB, the only ABC-type drug efflux pump inSalmonella, has previously been linked to virulence in mice. The molecular mechanism of this link betweenmacABand infection is unclear. We demonstrate thatmacABplays a role in the detoxification of reactive oxygen species (ROS), compounds that salmonellae are exposed to at various stages of infection.macABis induced upon exposure to H2O2and is critical for survival ofSalmonella entericaserovar Typhimurium in the presence of peroxide. Furthermore, we determined thatmacABis required for intracellular replication inside J774.A1 murine macrophages but is not required for survival in ROS-deficient J774.D9 macrophages.macABmutants also had reduced survival in the intestine in the mouse colitis model, a model characterized by a strong neutrophilic intestinal infiltrate where bacteria may experience the cytotoxic actions of ROS. Using an Amplex red-coupled assay,macABmutants appear to be unable to induce protection against exogenous H2O2in vitro, in contrast to the isogenic wild type. In mixed cultures, the presence of the wild-type organism, or media preconditioned by the growth of the wild-type organism, was sufficient to rescue themacABmutant from peroxide-mediated killing. Our data indicate that the MacAB drug efflux pump has functions beyond resistance to antibiotics and plays a role in the protection ofSalmonellaagainst oxidative stress. Intriguingly, our data also suggest the presence of a soluble anti-H2O2compound secreted bySalmonellacells through a MacAB-dependent mechanism.IMPORTANCEThe ABC-type multidrug efflux pump MacAB is known to be required forSalmonella entericaserovar Typhimurium virulence after oral infection in mice, yet the function of this pump during infection is unknown. We show that this pump is necessary for colonization of niches in infected mice where salmonellae encounter oxidative stress during infection. MacAB is required for growth in cultured macrophages that produce reactive oxygen species (ROS) but is not needed in macrophages that do not generate ROS. In addition, we show that MacAB is required to resist peroxide-mediated killingin vitroand for the inactivation of peroxide in the media. Finally, wild-type organisms, or supernatant from wild-type organisms grown in the presence of peroxide, rescue the growth defect ofmacABmutants in H2O2. MacAB appears to participate in the excretion of a compound that induces protection against ROS-mediated killing, revealing a new role for this multidrug efflux pump.

scholarly journals Redox Imbalance in T Cell-Mediated Skin Diseases

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Saveria Pastore ◽  
Liudmila Korkina
Keyword(s):  
Oxidative Stress ◽  
Atopic Dermatitis ◽  
Contact Dermatitis ◽  
Skin Diseases ◽  
Redox Balance ◽  
Inflammatory Disorder ◽  
Chronic Inflammatory Disorder ◽  
Physical Chemical ◽  
Chemical Oxidants ◽  
Beneficial Outcome

The skin is permanently exposed to physical, chemical, and biological aggression by the environment. In addition, acute and chronic inflammatory events taking place in the skin are accompanied by abnormal release of pro-oxidative mediators. In this paper, we will briefly overview the homeostatic systems active in the skin to maintain the redox balance and also to counteract abnormal oxidative stress. We will concentrate on the evidence that a local and/or systemic redox dysregulation accompanies the chronic inflammatory disorder events associated to psoriasis, contact dermatitis, and atopic dermatitis. We will also discuss the fact that several well-established treatments for the therapy of chronic inflammatory skin disorders are based on the application of strong physical or chemical oxidants onto the skin, indicating that, in selected conditions, a further increase of the oxidative imbalance may lead to a beneficial outcome.

scholarly journals The TonB system in Aeromonas hydrophila NJ-35 is essential for MacA2B2 efflux pump-mediated macrolide resistance

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Yuhao Dong ◽  
Qing Li ◽  
Jinzhu Geng ◽  
Qing Cao ◽  
Dan Zhao ◽  
...  
Keyword(s):  
Aeromonas Hydrophila ◽  
Efflux Pump ◽  
Fold Increase ◽  
Activity Level ◽  
Macrolide Resistance ◽  
Wild Type ◽  
Iron Deprivation ◽  
Pump Activity ◽  
Tonb System ◽  
Increased Sensitivity

AbstractThe TonB system is generally considered as an energy transporting device for the absorption of nutrients. Our recent study showed that deletion of this system caused a significantly increased sensitivity of Aeromonas hydrophila to the macrolides erythromycin and roxithromycin, but had no effect on other classes of antibiotics. In this study, we found the sensitivity of ΔtonB123 to all macrolides tested revealed a 8- to 16-fold increase compared with the wild-type (WT) strain, but this increase was not related with iron deprivation caused by tonB123 deletion. Further study demonstrated that the deletion of tonB123 did not damage the integrity of the bacterial membrane but did hinder the function of macrolide efflux. Compared with the WT strain, deletion of macA2B2, one of two ATP-binding cassette (ABC) types of the macrolide efflux pump, enhanced the sensitivity to the same levels as those of ΔtonB123. Interestingly, the deletion of macA2B2 in the ΔtonB123 mutant did not cause further increase in sensitivity to macrolide resistance, indicating that the macrolide resistance afforded by the MacA2B2 pump was completely abrogated by tonB123 deletion. In addition, macA2B2 expression was not altered in the ΔtonB123 mutant, indicating that any influence of TonB on MacA2B2-mediated macrolide resistance was at the pump activity level. In conclusion, inactivation of the TonB system significantly compromises the resistance of A. hydrophila to macrolides, and the mechanism of action is related to the function of MacA2B2-mediated macrolide efflux.

Streblus asper Lour. exerts MAPK and SKN-1 mediated anti-aging, anti-photoaging activities and imparts neuroprotection by ameliorating Aβ in Caenorhabditis elegans

2021 ◽  
pp. 1-17
Author(s):  
Mani Iyer Prasanth ◽  
James Michael Brimson ◽  
Dicson Sheeja Malar ◽  
Anchalee Prasansuklab ◽  
Tewin Tencomnao
Keyword(s):  
Oxidative Stress ◽  
Caenorhabditis Elegans ◽  
Stress Resistance ◽  
Vital Role ◽  
Transgenic Strain ◽  
Wild Type ◽  
Neuroprotective Effects ◽  
C Elegans ◽  
Streblus Asper

BACKGROUND: Streblus asper Lour., has been reported to have anti-aging and neuroprotective efficacies in vitro. OBJECTIVE: To analyze the anti-aging, anti-photoaging and neuroprotective efficacies of S. asper in Caenorhabditis elegans. METHODS: C. elegans (wild type and gene specific mutants) were treated with S. asper extract and analyzed for lifespan and other health benefits through physiological assays, fluorescence microscopy, qPCR and Western blot. RESULTS: The plant extract was found to increase the lifespan, reduce the accumulation of lipofuscin and modulate the expression of candidate genes. It could extend the lifespan of both daf-16 and daf-2 mutants whereas the pmk-1 mutant showed no effect. The activation of skn-1 was observed in skn-1::GFP transgenic strain and in qPCR expression. Further, the extract can extend the lifespan of UV-A exposed nematodes along with reducing ROS levels. Additionally, the extract also extends lifespan and reduces paralysis in Aβ transgenic strain, apart from reducing Aβ expression. CONCLUSIONS: S. asper was able to extend the lifespan and healthspan of C. elegans which was independent of DAF-16 pathway but dependent on SKN-1 and MAPK which could play a vital role in eliciting the anti-aging, anti-photoaging and neuroprotective effects, as the extract could impart oxidative stress resistance and neuroprotection.

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