A compensatory increase in trehalose synthesis in response to desiccation stress in Saccharomyces cerevisiae cells lacking the heat shock protein Hsp12p

2008 ◽  
Vol 54 (7) ◽  
pp. 559-568 ◽  
Author(s):  
Vanessa J. Shamrock ◽  
George G. Lindsey
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Flow Cytometry ◽  
Type Strain ◽  
Wild Type Strain ◽  
Membrane Integrity ◽  
Oxygen Species ◽  
Wild Type ◽  
Plasma Membrane Integrity ◽  
Trehalose Synthesis

The effect of HSP12 deletion on the response of yeast to desiccation was investigated. The Δhsp12 strain was found to be more desiccation tolerant than the wild-type strain. Furthermore, the increased intracellular trehalose levels in the Δhsp12 strain suggested that this strain compensated for the lack of Hsp12p synthesis by increasing trehalose synthesis, which facilitated increased desiccation tolerance. Results obtained from flow cytometry using the membrane exclusion dye propidium iodide suggested that Hsp12p helped maintain plasma membrane integrity during desiccation. Analysis of the oxidative loads experienced by the wild-type and Δhsp12 strains showed that during mid-exponential phase, the increased trehalose levels present in the Δhsp12 cells resulted in increased protection of these cells against reactive oxygen species compared with wild-type cells. During stationary phase, lower levels of reactive oxygen species reduction by reduced glutathione was enhanced in the wild-type strain, which displayed lower intracellular trehalose concentrations. Comparison of the tolerance of the wild-type and Δhsp12 strains with applied oxidative stress showed that the Δhsp12 strain was more tolerant to exogenously applied H2O2, which we attributed to the higher intracellular trehalose concentration. Flow cytometry demonstrated that Hsp12p played a role in maintaining plasma membrane integrity during applied oxidative stress.

scholarly journals The Gene yggE Functions in Restoring Physiological Defects of Escherichia coli Cultivated under Oxidative Stress Conditions

2005 ◽  
Vol 71 (5) ◽  
pp. 2762-2765 ◽  
Author(s):  
SunYoung Kim ◽  
Motomu Nishioka ◽  
Shuhei Hayashi ◽  
Hiroyuki Honda ◽  
Takeshi Kobayashi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Type Strain ◽  
Wild Type Strain ◽  
Specific Growth ◽  
Maximum Specific Growth Rate ◽  
Oxygen Species ◽  
Wild Type ◽  
Amino Acid Requirement ◽  
E Coli

ABSTRACT DNA microarray analysis showed that yfiD, yggB, and yggE genes were up-regulated when superoxide dismutase (SOD)-deficient Escherichia coli IM303 (I4) was cultivated under the oxidative stress generated by photoexcited TiO2, and pYFD, pYGB, and pYGE were constructed by inserting the respective genes into a pUC 19 vector. The content of reactive oxygen species (ROS) in IM303 (I4) cells carrying pYGE was reduced to 31% of ROS content in the control cells with pUC 19. In the culture of wild-type strain, E. coli MM294, in the medium with paraquat (10 μmol/l), maximum specific growth rate of the cells with pYGE was about five times higher than that of the control cells, with a decreased ROS content in the former cells. The introduction of pYGE also suppressed the occurrence of the cells with altered amino acid requirement in the culture of MM294 cells with paraquat.

scholarly journals Sml1 Inhibits the DNA Repair Activity of Rev1 in Saccharomyces cerevisiae during Oxidative Stress

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Rui Yao ◽  
Pei Zhou ◽  
Chengjin Wu ◽  
Liming Liu ◽  
Jing Wu
Keyword(s):  
Oxidative Stress ◽  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Survival Rate ◽  
Type Strain ◽  
Mutation Frequency ◽  
Wild Type Strain ◽  
Yeast Cells ◽  
Wild Type ◽  
Content Type

ABSTRACT In Saccharomyces cerevisiae, Y family DNA polymerase Rev1 is involved in the repair of DNA damage by translesion DNA synthesis (TLS). In the current study, to elucidate the role of Rev1 in oxidative stress-induced DNA damage in S. cerevisiae, REV1 was deleted and overexpressed; transcriptome analysis of these mutants along with the wild-type strain was performed to screen potential genes that could be associated with REV1 during response to DNA damage. When the yeast cells were treated with 2 mM H2O2, the deletion of REV1 resulted in a 1.5- and 2.8-fold decrease in the survival rate and mutation frequency, respectively, whereas overexpression of REV1 increased the survival rate and mutation frequency by 1.1- and 2.9-fold, respectively, compared to the survival rate and mutation frequency of the wild-type strain. Transcriptome and phenotypic analyses identified that Sml1 aggravated oxidative stress in the yeast cells by inhibiting the activity of Rev1. This inhibition was due to the physical interaction between the BRCA1 C terminus (BRCT) domain of Rev1 and amino acid residues 36 to 70 of Sml1; the cell survival rate and mutation frequency increased by 1.8- and 3.1-fold, respectively, when this interaction was blocked. We also found that Sml1 inhibited Rev1 phosphorylation under oxidative stress and that deletion of SML1 increased the phosphorylation of Rev1 by 46%, whereas overexpression of SML1 reduced phosphorylation of Rev1. Overall, these findings demonstrate that Sml1 could be a novel regulator that mediates Rev1 dephosphorylation to inhibit its activity during oxidative stress. IMPORTANCE Rev1 was critical for cell growth in S. cerevisiae, and the deletion of REV1 caused a severe growth defect in cells exposed to oxidative stress (2 mM H2O2). Furthermore, we found that Sml1 physically interacted with Rev1 and inhibited Rev1 phosphorylation, thereby inhibiting Rev1 DNA antioxidant activity. These findings indicate that Sml1 could be a novel regulator for Rev1 in response to DNA damage by oxidative stress.

scholarly journals Evidence for a Role of rpoE in Stressed and Unstressed Cells of Marine Vibrio angustumStrain S14

2000 ◽  
Vol 182 (24) ◽  
pp. 6964-6974 ◽  
Author(s):  
Erika Hild ◽  
Kathy Takayama ◽  
Rose-Marie Olsson ◽  
Staffan Kjelleberg
Keyword(s):  
Oxidative Stress ◽  
Blot Analysis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Sequence Similarity ◽  
Temperature Shift ◽  
Optimal Growth ◽  
Single Copy ◽  
Carbon Starvation ◽  
Wild Type

ABSTRACT We report the cloning, sequencing, and characterization of therpoE homolog in Vibrio angustum S14. TherpoE gene encodes a protein with a predicted molecular mass of 19.4 kDa and has been demonstrated to be present as a single-copy gene by Southern blot analysis. The deduced amino acid sequence of RpoE is most similar to that of the RpoE homolog of Sphingomonas aromaticivorans, ς24, displaying sequence similarity and identity of 63 and 43%, respectively. Northern blot analysis demonstrated the induction of rpoE 6, 12, and 40 min after a temperature shift to 40°C. An rpoE mutant was constructed by gene disruption. There was no difference in viability during logarithmic growth, stationary phase, or carbon starvation between the wild type and the rpoE mutant strain. In contrast, survival of the mutant was impaired following heat shock during exponential growth, as well as after oxidative stress at 24 h of carbon starvation. The mutant exhibited microcolony formation during optimal growth temperatures (22 to 30°C), and cell area measurements revealed an increase in cell volume of the mutant during growth at 30°C, compared to the wild-type strain. Moreover, outer membrane and periplasmic space protein analysis demonstrated many alterations in the protein profiles for the mutant during growth and carbon starvation, as well as following oxidative stress, in comparison with the wild-type strain. It is thereby concluded that RpoE has an extracytoplasmic function and mediates a range of specific responses in stressed as well as unstressed cells of V. angustum S14.

scholarly journals The Characterization of TA-289, a Novel Antifungal from Fusarium sp.

2021 ◽  
Author(s):  
◽  
Natelle C H Quek
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Cell Cycle ◽  
Cell Death ◽  
Reactive Oxygen ◽  
Chemical Diversity ◽  
Mitochondrial Morphology ◽  
Ros Production ◽  
Oxygen Species ◽  
Wild Type

<p>Natural products offer vast structural and chemical diversity highly sought after in drug discovery research. Saccharomyces cerevisiae makes an ideal model eukaryotic organism for drug mode-of-action studies owing to ease of growth, sophistication of genetic tools and overall homology to higher eukaryotes. Equisetin and a closely related novel natural product, TA-289, are cytotoxic to fermenting yeast, but seemingly less so when yeast actively respire. Cell cycle analyses by flow cytometry revealed a cell cycle block at S-G2/M phase caused by TA-289; previously described oxidative stress-inducing compounds causing cell cycle delay led to further investigation in the involvement of equisetin and TA-289 in mitochondrial-mediated generation of reactive oxygen species. Chemical genomic profiling involving genome-wide scans of yeast deletion mutant strains for TA-289 sensitivity revealed sensitization of genes involved in the mitochondria, DNA damage repair and oxidative stress responses, consistent with a possible mechanism-of-action at the mitochondrion. Flow cytometric detection of reactive oxygen species (ROS) generation caused by TA-289 suggests that the compound may induce cell death via ROS production. The generation of a mutant strain resistant to TA-289 also displayed resistance to a known oxidant, H2O2, at concentrations that were cytotoxic to wild-type cells. The resistant mutant displayed a higher basal level of ROS production compared to the wild-type parent, indicating that the resistance mutation led to an up-regulation of antioxidant capacity which provides cell survival in the presence of TA-289. Yeast mitochondrial morphology was visualized by confocal light microscopy, where it was observed that cells treated with TA-289 displayed abnormal mitochondria phenotypes, further indicating that the compound is acting primarily at the mitochondrion. Similar effects observed with equisetin treatment suggest that both compounds share the same mechanism, eliciting cell death via ROS production in the mitochondrial respiratory chain.</p>

scholarly journals CgHog1-Mediated CgRds2 Phosphorylation Alters Glycerophospholipid Composition To Coordinate Osmotic Stress in Candida glabrata

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Chengjin Wu ◽  
Jiali Zhang ◽  
Guoxing Zhu ◽  
Rui Yao ◽  
Xiulai Chen ◽  
...  
Keyword(s):  
Cell Growth ◽  
Osmotic Stress ◽  
Cell Survival ◽  
Type Strain ◽  
Candida Glabrata ◽  
Wild Type Strain ◽  
Membrane Integrity ◽  
Wild Type ◽  
Content Type ◽  
Zinc Cluster

ABSTRACT Under stress conditions, Hog1 is required for cell survival through transiently phosphorylating downstream targets and reprogramming gene expression. Here, we report that Candida glabrata Hog1 (CgHog1) interacts with and phosphorylates CgRds2, a zinc cluster transcription factor, in response to osmotic stress. Additionally, we found that deletion of CgRDS2 led to decreases in cell growth and cell survival by 23.4% and 39.6%, respectively, at 1.5 M NaCl, compared with levels of the wild-type strain. This is attributed to significant downregulation of the expression levels of glycerophospholipid metabolism genes. As a result, the content of total glycerophospholipid decreased by 30.3%. Membrane integrity also decreased 47.6% in the Cgrds2Δ strain at 1.5 M NaCl. In contrast, overexpression of CgRDS2 increased the cell growth and cell survival by 10.2% and 6.3%, respectively, owing to a significant increase in the total glycerophospholipid content and increased membrane integrity by 27.2% and 12.1%, respectively, at 1.5 M NaCl, compared with levels for the wild-type strain. However, a strain in which the CgRDS2 gene encodes the replacement of Ser64 and Thr97 residues with alanines (Cgrds22A), harboring a CgRds2 protein that was not phosphorylated by CgHog1, failed to promote glycerophospholipid metabolism and membrane integrity at 1.5 M NaCl. Thus, the above results demonstrate that CgHog1-mediated CgRds2 phosphorylation enhanced glycerophospholipid composition and membrane integrity to resist osmotic stress in C. glabrata. IMPORTANCE This study explored the role of CgHog1-mediated CgRds2 phosphorylation in response to osmotic stress in Candida glabrata. CgHog1 interacts with and phosphorylates CgRds2, a zinc cluster transcription factor, under osmotic stress. Phosphorylated CgRds2 plays an important role in increasing glycerophospholipid composition and membrane integrity, thereby enhancing cell growth and survival.

scholarly journals Contribution of YjbIH to Virulence Factor Expression and Host Colonization inStaphylococcus aureus

2019 ◽  
Vol 87 (6) ◽  
Author(s):  
Crystal M. Austin ◽  
Siamak Garabaglu ◽  
Christina N. Krute ◽  
Miranda J. Ridder ◽  
Nichole A. Seawell ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Virulence Factor ◽  
Type Strain ◽  
Wild Type Strain ◽  
Acute Infection ◽  
Minor Role ◽  
Wild Type ◽  
Truncated Hemoglobin ◽  
Factor Expression ◽  
And Oxidative Stress

ABSTRACTTo persist within the host and cause disease,Staphylococcus aureusrelies on its ability to precisely fine-tune virulence factor expression in response to rapidly changing environments. During an unbiased transposon mutant screen, we observed that disruption of a two-gene operon,yjbIH, resulted in decreased levels of pigmentation and aureolysin (Aur) activity relative to the wild-type strain. Further analyses revealed that YjbH, a predicted thioredoxin-like oxidoreductase, is predominantly responsible for the observedyjbIHmutant phenotypes, though a minor role exists for the putative truncated hemoglobin YjbI. These differences were due to significantly decreased expression ofcrtOPQMNandaur. Previous studies found that YjbH targets the disulfide- and oxidative stress-responsive regulator Spx for degradation by ClpXP. The absence ofyjbHoryjbIresulted in altered sensitivities to nitrosative and oxidative stress and iron deprivation. Additionally, aconitase activity was altered in theyjbHandyjbImutant strains. Decreased levels of pigmentation and aureolysin (Aur) activity in theyjbHmutant were found to be Spx dependent. Lastly, we used a murine sepsis model to determine the effect of theyjbIHdeletion on pathogenesis and found that the mutant was better able to colonize the kidneys and spleens during an acute infection than the wild-type strain. These studies identified changes in pigmentation and protease activity in response to YjbIH and are the first to have shown a role for these proteins during infection.

Transferrin Receptor 1 Up-Regulation Plays a Role in Iron Accumulation in a Murine Model of Sideroblastic Anemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3585-3585
Author(s):  
Florent M. Martin ◽  
Timothy J. Gilmartin ◽  
Gabriela Bydlon ◽  
Megan L. Welsh ◽  
Jeffrey S. Friedman
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Stem Cells ◽  
Transferrin Receptor ◽  
Iron Homeostasis ◽  
Oxygen Species ◽  
Wild Type ◽  
Sideroblastic Anemia ◽  
Hematopoietic Stem ◽  
Transferrin Receptor 1

Abstract Manganese superoxide dismutase (SOD2) detoxifies superoxide anion radicals generated by mitochondrial respiration (Weisiger and Fridovich, J. Biol. Chem. 1973). While SOD2-deficiency is lethal, SOD2-deficient (SOD2−/−) hematopoietic stem cells can rescue lethally irradiated wild-type mice. SOD2−/− hematopoietic chimeras show a persistent hemolytic anemia similar to human sideroblastic anemia (Friedman et al. J. Exp. Med. 2001). SOD2−/− erythroid progenitor cells have increased mitochondrial mass, and reticulocytes show mitochondrial iron deposition. Mature RBC show abundant siderotic granules, evidence of a defect in iron incorporation into heme, and shortened lifespan. SOD2−/− progenitors and mature RBC show both enhanced reactive oxygen species production and protein oxidative damage (Friedman et al. Blood 2004; Martin et al. Submitted). To define early events in the pathogenesis of the SOD2-deficiency anemia and, in particular to identify genes involved in the response of erythroid progenitors to oxidative stress, we compared gene expression of sorted TER-119+ CD71+ erythroblasts from SOD2−/−versus wild-type hematopoietic stem cells recipients. Using cDNA microarrays and class comparison analysis, we identified 600 transcripts as significantly discriminant between genotypes. Analysis showed that eleven transcripts encoding different subunits of the mitochondrial oxidative phosphorylation, ATP synthase, and TCA cycle were down-regulated in SOD2−/− erythroblasts. Previous work showed similar results at the protein level in SOD2−/− RBC (Friedman et al. Blood 2004) and at the activity level in specific tissues of SOD2−/− neonates prior to death (Melov et al. PNAS 1999). One interpretation is that SOD2−/− erythroblasts show metabolic decline. Of interest, a single transcript involved in iron homeostasis, Trfr, was found to be expressed at twice the levels found in wild-type erythroblasts (p&lt;0.0007, parametric p value). Trfr encodes transferrin receptor 1; two-fold up-regulation of transferrin receptor 1 was also shown at the protein level by flow cytometry analysis of SOD2−/− erythroblasts (p&lt;0.0001, unpaired two-tailed t-test). Transferrin receptor 1 is the cellular gatekeeper for iron uptake whose genetic inactivation induces abnormal erythropoiesis and iron homeostasis (Levy et al. Nat. Genet. 1999). The stability of the Trfr transcript is highly regulated by iron regulatory proteins (IRPs), that are known to be controlled by numerous effectors including reactive oxygen species (Hentze et al. Cell 2004, for review). We focus our current work on investigating, in vitro and in vivo, the role that up-regulation of transferrin receptor 1, likely through oxidative stress-mediated IRPs activity regulation, plays in iron overload in our SOD2-deficiency model. Taken together, our findings raise the possibility that increased iron delivery may be sufficient to cause sideroblastic anemia or may contribute to a self-reinforcing cycle where oxidative stress favors increased iron, and increased iron results in enhanced oxidative damage.

scholarly journals Global Analysis of Cellular Factors and Responses Involved in Pseudomonas aeruginosa Resistance to Arsenite

2005 ◽  
Vol 187 (14) ◽  
pp. 4853-4864 ◽  
Author(s):  
Kislay Parvatiyar ◽  
Eyad M. Alsabbagh ◽  
Urs A. Ochsner ◽  
Michelle A. Stegemeyer ◽  
Alan G. Smulian ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Glutathione Reductase ◽  
Type Strain ◽  
Wild Type Strain ◽  
Storage Proteins ◽  
Global Analysis ◽  
Wild Type ◽  
Isogenic Mutants ◽  
The Impact

ABSTRACT The impact of arsenite [As(III)] on several levels of cellular metabolism and gene regulation was examined in Pseudomonas aeruginosa. P. aeruginosa isogenic mutants devoid of antioxidant enzymes or defective in various metabolic pathways, DNA repair systems, metal storage proteins, global regulators, or quorum sensing circuitry were examined for their sensitivity to As(III). Mutants lacking the As(III) translocator (ArsB), superoxide dismutase (SOD), catabolite repression control protein (Crc), or glutathione reductase (Gor) were more sensitive to As(III) than wild-type bacteria. The MICs of As(III) under aerobic conditions were 0.2, 0.3, 0.8, and 1.9 mM for arsB, sodA sodB, crc, and gor mutants, respectively, and were 1.5- to 13-fold less than the MIC for the wild-type strain. A two-dimensional gel/matrix-assisted laser desorption ionization-time of flight analysis of As(III)-treated wild-type bacteria showed significantly (>40-fold) increased levels of a heat shock protein (IbpA) and a putative allo-threonine aldolase (GlyI). Smaller increases (up to 3.1-fold) in expression were observed for acetyl-coenzyme A acetyltransferase (AtoB), a probable aldehyde dehydrogenase (KauB), ribosomal protein L25 (RplY), and the probable DNA-binding stress protein (PA0962). In contrast, decreased levels of a heme oxygenase (HemO/PigA) were found upon As(III) treatment. Isogenic mutants were successfully constructed for six of the eight genes encoding the aforementioned proteins. When treated with sublethal concentrations of As(III), each mutant revealed a marginal to significant lag period prior to resumption of apparent normal growth compared to that observed in the wild-type strain. Our results suggest that As(III) exposure results in an oxidative stress-like response in P. aeruginosa, although activities of classic oxidative stress enzymes are not increased. Instead, relief from As(III)-based oxidative stress is accomplished from the collective activities of ArsB, glutathione reductase, and the global regulator Crc. SOD appears to be involved, but its function may be in the protection of superoxide-sensitive sulfhydryl groups.

scholarly journals Inactivation of Escherichia coli by Nanoparticulate Zerovalent Iron and Ferrous Ion

2010 ◽  
Vol 76 (22) ◽  
pp. 7668-7670 ◽  
Author(s):  
Jee Yeon Kim ◽  
Hee-Jin Park ◽  
Changha Lee ◽  
Kara L. Nelson ◽  
David L. Sedlak ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Reactive Oxygen Species ◽  
Cell Membrane ◽  
Respiratory Activity ◽  
Membrane Integrity ◽  
Ferrous Ion ◽  
Zerovalent Iron ◽  
Oxygen Species ◽  
Cell Membrane Integrity

ABSTRACT The mechanism of Escherichia coli inactivation by nanoparticulate zerovalent iron (nZVI) and Fe(II) was investigated using reactive oxygen species (ROS) quenchers and probes, an oxidative stress assay, and microscopic observations. Disruption of cell membrane integrity and respiratory activity was observed under deaerated conditions [more disruption by nZVI than Fe(II)], and OH or Fe(IV) appears to play a role.

scholarly journals Functional Analysis of preA in Aeromonas veronii TH0426 Reveals a Key Role in the Regulation of Virulence and Resistance to Oxidative Stress

2019 ◽  
Vol 21 (1) ◽  
pp. 98
Author(s):  
Bintong Yang ◽  
Haichao Song ◽  
Dingjie An ◽  
Dongxing Zhang ◽  
Sayed Haidar Abbas Raza ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Type Strain ◽  
Wild Type Strain ◽  
Lethal Dose ◽  
Tolerance Test ◽  
Economic Losses ◽  
Cytotoxicity Test ◽  
Test Results ◽  
Wild Type ◽  
Aeromonas Veronii

Aeromonas veronii is one of the main pathogens causing freshwater fish sepsis and ulcer syndrome. This bacterium has caused serious economic losses in the aquaculture industry worldwide, and it has become an important zoonotic and aquatic agent. However, little is known about the molecular mechanism of pathogenesis of A. veronii. In this study, we first constructed an unmarked mutant strain (ΔpreA) by generating an in-frame deletion of the preA gene, which encodes a periplasmic binding protein, to investigate its role in A. veronii TH0426. Our results showed that the motility and biofilm formation ability of ΔpreA were similar to those of the wild-type strain. However, the adhesion and invasion ability in epithelioma papulosum cyprini (EPC) cells were significantly enhanced (2.0-fold). Furthermore, the median lethal dose (LD50) of ΔpreA was 7.6-fold higher than that of the wild-type strain, which illustrates that the virulence of the mutant was significantly enhanced. This finding is also supported by the cytotoxicity test results, which showed that the toxicity of ΔpreA to EPC cells was enhanced 1.3-fold relative to the wild type. Conversely, tolerance test results showed that oxidative stress resistance of ΔpreA decreased 5.9-fold compared to with the wild-type strain. The results suggest that preA may negatively regulate the virulence of A. veronii TH0426 through the regulation of resistance to oxidative stress. These insights will help to further elucidate the function of preA and understand the pathogenesis of A. veronii.

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