scholarly journals Transcriptional and Proteomic Analysis of a Ferric Uptake Regulator (Fur) Mutant of Shewanella oneidensis: Possible Involvement of Fur in Energy Metabolism, Transcriptional Regulation, and Oxidative Stress

2002 ◽  
Vol 68 (2) ◽  
pp. 881-892 ◽  
Author(s):  
Dorothea K. Thompson ◽  
Alexander S. Beliaev ◽  
Carol S. Giometti ◽  
Sandra L. Tollaksen ◽  
Tripti Khare ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcriptional Regulation ◽  
Energy Metabolism ◽  
Type Strain ◽  
Wild Type Strain ◽  
Shewanella Oneidensis ◽  
Anaerobic Growth ◽  
Ferric Uptake Regulator ◽  
Wild Type ◽  
And Oxidative Stress

ABSTRACT The iron-directed, coordinate regulation of genes depends on the fur (ferric uptake regulator) gene product, which acts as an iron-responsive, transcriptional repressor protein. To investigate the biological function of a fur homolog in the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1, a fur knockout strain (FUR1) was generated by suicide plasmid integration into this gene and characterized using phenotype assays, DNA microarrays containing 691 arrayed genes, and two-dimensional polyacrylamide gel electrophoresis. Physiological studies indicated that FUR1 was similar to the wild-type strain when they were compared for anaerobic growth and reduction of various electron acceptors. Transcription profiling, however, revealed that genes with predicted functions in electron transport, energy metabolism, transcriptional regulation, and oxidative stress protection were either repressed (ccoNQ, etrA, cytochrome b and c maturation-encoding genes, qor, yiaY, sodB, rpoH, phoB, and chvI) or induced (yggW, pdhC, prpC, aceE, fdhD, and ppc) in the fur mutant. Disruption of fur also resulted in derepression of genes (hxuC, alcC, fhuA, hemR, irgA, and ompW) putatively involved in iron uptake. This agreed with the finding that the fur mutant produced threefold-higher levels of siderophore than the wild-type strain under conditions of sufficient iron. Analysis of a subset of the FUR1 proteome (i.e., primarily soluble cytoplasmic and periplasmic proteins) indicated that 11 major protein species reproducibly showed significant (P < 0.05) differences in abundance relative to the wild type. Protein identification using mass spectrometry indicated that the expression of two of these proteins (SodB and AlcC) correlated with the microarray data. These results suggest a possible regulatory role of S. oneidensis MR-1 Fur in energy metabolism that extends the traditional model of Fur as a negative regulator of iron acquisition systems.

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.

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 A Mutation in the 3-Phosphoglycerate Kinase Gene Allows Anaerobic Growth of Bacillus subtilis in the Absence of ResE Kinase

1999 ◽  
Vol 181 (22) ◽  
pp. 7087-7097 ◽  
Author(s):  
Michiko M. Nakano ◽  
Yi Zhu ◽  
Koki Haga ◽  
Hirofumi Yoshikawa ◽  
Abraham L. Sonenshein ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Response Regulator ◽  
Anaerobic Respiration ◽  
Phosphoglycerate Kinase ◽  
Anaerobic Growth ◽  
Wild Type ◽  
Kinase Gene ◽  
Glycolytic Intermediate

ABSTRACT The Bacillus subtilis ResD-ResE two-component signal transduction system is essential for aerobic and anaerobic respiration. A spontaneous suppressor mutant that expresses ResD-controlled genes and grows anaerobically in the absence of the ResE histidine kinase was isolated. In addition, aerobic expression of ResD-controlled genes in the suppressed strain was constitutive and occurred at a much higher level than that observed in the wild-type strain. The suppressing mutation, which mapped to pgk, the gene encoding 3-phosphoglycerate kinase, failed to suppress a resDmutation, suggesting that the suppressing mutation creates a pathway for phosphorylation of the response regulator, ResD, which is independent of the cognate sensor kinase, ResE. The pgk-1mutant exhibited very low but measurable 3-phosphoglycerate kinase activity compared to the wild-type strain. The results suggest that accumulation of a glycolytic intermediate, probably 1,3-diphosphoglycerate, is responsible for the observed effect of thepgk-1 mutation on anaerobiosis of resE mutant cells.

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 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.

The dependence of Escherichia coli asparaginase II formation on cyclic AMP and cyclic AMP receptor protein

1978 ◽  
Vol 24 (5) ◽  
pp. 629-631 ◽  
Author(s):  
La Verne Russell ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Cyclic Amp ◽  
Type Strain ◽  
Wild Type Strain ◽  
Anaerobic Growth ◽  
Receptor Protein ◽  
Wild Type ◽  
Cyclic Amp Receptor Protein ◽  
E Coli ◽  
Cyclic Amp Synthesis

The amount of asparaginase II in an Escherichia coli wild-type strain (cya+, crp+) markedly increased upon a shift from aerobic to anaerobic growth. However, no such increase occurred in a mutant (cya) lacking cyclic AMP synthesis unless supplemented with exogenous cyclic AMP. Since a mutant (crp) deficient in cyclic AMP receptor protein also did not support the anaerobic formation of this enzyme, it is concluded that the formation of E. coli asparaginase II depends on both cyclic AMP and cyclic AMP receptor protein.

scholarly journals Mycobacterium smegmatisl-Alanine Dehydrogenase (Ald) Is Required for Proficient Utilization of Alanine as a Sole Nitrogen Source and Sustained Anaerobic Growth

2002 ◽  
Vol 184 (18) ◽  
pp. 5001-5010 ◽  
Author(s):  
Zhengyu Feng ◽  
Nancy E. Cáceres ◽  
Gautam Sarath ◽  
Raúl G. Barletta
Keyword(s):  
Enzyme Activity ◽  
Nitrogen Source ◽  
Type Strain ◽  
Growth Stage ◽  
Reductive Amination ◽  
Wild Type Strain ◽  
Anaerobic Growth ◽  
Sole Nitrogen Source ◽  
Wild Type ◽  
Anaerobic Conditions

ABSTRACT NAD(H)-dependent l-alanine dehydrogenase (EC 1.4.1.1) (Ald) catalyzes the oxidative deamination of l-alanine and the reductive amination of pyruvate. To assess the physiological role of Ald in Mycobacterium smegmatis, we cloned the ald gene, identified its promoter, determined the protein expression levels, and analyzed the combined effects of nutrient supplementation, oxygen availability, and growth stage on enzyme activity. High Ald activities were observed in cells grown in the presence of l- or d-alanine regardless of the oxygen availability and growth stage. In exponentially growing cells under aerobic conditions, supplementation with alanine resulted in a 25- to 50-fold increase in the enzyme activity. In the absence of alanine supplementation, 23-fold-higher Ald activities were observed in cells grown exponentially under anaerobic conditions. Furthermore, M. smegmatis ald null mutants were constructed by targeted disruption and were shown to lack any detectable Ald activity. In contrast, the glycine dehydrogenase (EC 1.4.1.10) (Gdh) activity in mutant cells remained at wild-type levels, indicating that another enzyme protein is responsible for the physiologically relevant reductive amination of glyoxylate. The ald mutants grew poorly in minimal medium with l-alanine as the sole nitrogen source, reaching a saturation density 100-fold less than that of the wild-type strain. Likewise, mutants grew to a saturation density 10-fold less than that of the wild-type strain under anaerobic conditions. In summary, the phenotypes displayed by the M. smegmatis ald mutants suggest that Ald plays an important role in both alanine utilization and anaerobic growth.

scholarly journals A Second Two-Component Regulatory System of Bordetella bronchiseptica Required for Bacterial Resistance to Oxidative Stress, Production of Acid Phosphatase, and In Vivo Persistence

1998 ◽  
Vol 66 (10) ◽  
pp. 4640-4650 ◽  
Author(s):  
Heidrun Jungnitz ◽  
Nicholas P. West ◽  
Mark J. Walker ◽  
Gursharan S. Chhatwal ◽  
Carlos A. Guzmán
Keyword(s):  
Oxidative Stress ◽  
Acid Phosphatase ◽  
Type Strain ◽  
Bacterial Resistance ◽  
Wild Type Strain ◽  
Regulatory System ◽  
Bordetella Bronchiseptica ◽  
Mammalian Host ◽  
Wild Type ◽  
Two Component

ABSTRACT Random minitransposon mutagenesis was used to identify genes involved in the survival of Bordetella bronchiseptica within eukaryotic cells. One of the mutants which exhibited a reduced ability to survive intracellularly harbored a minitransposon insertion in a locus (ris) which displays a high degree of homology to two-component regulatory systems. This system exhibited less than 25% amino acid sequence homology to the only other two-component regulatory system described in Bordetellaspp., the bvg locus. A risA′-′lacZtranslational fusion was constructed and integrated into the chromosome of B. bronchiseptica. Determination of β-galactosidase activity under different environmental conditions suggested that ris is regulated independently ofbvg and is optimally expressed at 37°C, in the absence of Mg2+, and when bacteria are in the intracellular niche. This novel regulatory locus, present in all Bordetellaspp., is required for the expression of acid phosphatase byB. bronchiseptica. Although catalase and superoxide dismutase production were unaffected, the ris mutant was more sensitive to oxidative stress than the wild-type strain. Complementation of bvg-positive andbvg-negative ris mutants with the intact ris operon incorporated as a single copy into the chromosome resulted in the reestablishment of the ability of the bacterium to produce acid phosphatase and to resist oxidative stress. Mouse colonization studies demonstrated that the ris mutant is cleared by the host much earlier than the wild-type strain, suggesting that ris-regulated products play a significant role in natural infections. The identification of a second two-component system in B. bronchiseptica highlights the complexity of the regulatory network needed for organisms with a life cycle requiring adaptation to both the external environment and a mammalian host.

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.

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