scholarly journals Role of ςB in Heat, Ethanol, Acid, and Oxidative Stress Resistance and during Carbon Starvation inListeria monocytogenes

2001 ◽  
Vol 67 (10) ◽  
pp. 4454-4457 ◽  
Author(s):  
Adriana Ferreira ◽  
Conor P. O'Byrne ◽  
Kathryn J. Boor
Keyword(s):  
Oxidative Stress ◽  
Stationary Phase ◽  
Stress Resistance ◽  
Parent Strain ◽  
Acid Resistance ◽  
Carbon Starvation ◽  
Wild Type ◽  
Oxidative Stress Resistance ◽  
And Oxidative Stress ◽  
Dependent Mechanism

ABSTRACT To determine the contribution of sigma B (ςB) to survival of stationary-phase Listeria monocytogenescells following exposure to environmental stresses, we compared the viability of strain 10403S with that of an isogenic nonpolarsigB null mutant strain after exposure to heat (50°C), ethanol (16.5%), or acid (pH 2.5). Strain viabilities were also determined under the same conditions in cultures that had been previously exposed to sublethal levels of the same stresses (45°C, 5% ethanol, or pH 4.5). The ΔsigB and wild-type strains had similar viabilities following exposure to ethanol and heat, but the ΔsigB strain was almost 10,000-fold more susceptible to lethal acid stress than its parent strain. However, a 1-h preexposure to pH 4.5 yielded a 1,000-fold improvement in viability for the ΔsigB strain. These results suggest the existence in L. monocytogenes of both a ςB-dependent mechanism and a pH-dependent mechanism for acid resistance in the stationary phase. ςB contributed to resistance to both oxidative stress and carbon starvation inL. monocytogenes. The ΔsigB strain was 100-fold more sensitive to 13.8 mM cumene hydroperoxide than the wild-type strain. Following glucose depletion, the ΔsigB strain lost viability more rapidly than the parent strain. ςB contributions to viability during carbon starvation and to acid resistance and oxidative stress resistance support the hypothesis that ςB plays a role in protecting L. monocytogenes against environmental adversities.

scholarly journals Gengnianchun, a Traditional Chinese Medicine, Enhances Oxidative Stress Resistance and Lifespan in Caenorhabditis elegans by Modulating daf-16/FOXO

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Fanhui Meng ◽  
Jun Li ◽  
Wenjun Wang ◽  
Yan Fu
Keyword(s):  
Oxidative Stress ◽  
Caenorhabditis Elegans ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Stress Resistance ◽  
Transgenic Animals ◽  
Wild Type ◽  
Oxidative Stress Resistance ◽  
C Elegans ◽  
And Oxidative Stress

Objective. Gengnianchun (GNC), a traditional Chinese medicine (TCM), is primarily used to improve declining functions related to aging. In this study, we investigated its prolongevity and stress resistance properties and explored the associated regulatory mechanism using a Caenorhabditis elegans model. Methods. Wild-type C. elegans N2 was used for lifespan analysis and oxidative stress resistance assays. Transgenic animals were used to investigate pathways associated with antioxidative stress activity. The effects of GNC on levels of reactive oxygen species (ROS) and expression of specific genes were examined. Results. GNC-treated wild-type worms showed an increase in survival time under both normal and oxidative stress conditions. GNC decreased intracellular ROS levels by 67.95%. GNC significantly enhanced the oxidative stress resistance of several mutant strains, suggesting that the protective effect of GNC is independent of the function of these genes. However, the oxidative stress resistance effect of GNC was absent in worms with daf-16 mutation. We also found upregulation of daf-16 downstream targets including sod-3 and mtl-1. Conclusions. Our findings suggest that GNC extends the lifespan of C. elegans and enhances its resistance to oxidative stress via a daf-16/FOXO-dependent pathway. This study also provides a feasible method for screening the biological mechanisms of TCMs.

Functional characterization of a mycothiol peroxidase in Corynebacterium glutamicum that uses both mycoredoxin and thioredoxin reducing systems in the response to oxidative stress

2015 ◽  
Vol 469 (1) ◽  
pp. 45-57 ◽  
Author(s):  
Meiru Si ◽  
Yixiang Xu ◽  
Tietao Wang ◽  
Mingxiu Long ◽  
Wei Ding ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Corynebacterium Glutamicum ◽  
Stress Resistance ◽  
Functional Characterization ◽  
Gram Positive ◽  
Oxidative Stress Resistance ◽  
Proton Donors ◽  
New Type ◽  
And Oxidative Stress

Mycothiol peroxidase, a new type of GSH peroxidase distributed in GSH-lacking high-(G+C)-content Gram-positive actinobacteria, uses both mycoredoxin and thioredoxin systems as proton donors for regeneration and oxidative stress resistance.

scholarly journals Cyanobacterial Mn-catalase ‘KatB’: Molecular link between salinity and oxidative stress resistance

2016 ◽  
Vol 9 (5) ◽  
pp. e1216738 ◽  
Author(s):  
Dhiman Chakravarty ◽  
Manisha Banerjee ◽  
Namrata Waghmare ◽  
Anand Ballal
Keyword(s):  
Oxidative Stress ◽  
Stress Resistance ◽  
Oxidative Stress Resistance ◽  
And Oxidative Stress

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.

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