scholarly journals The Role of PerR in O2-Affected Gene Expression of Clostridium acetobutylicum

2009 ◽  
Vol 191 (19) ◽  
pp. 6082-6093 ◽  
Author(s):  
Falk Hillmann ◽  
Christina Döring ◽  
Oliver Riebe ◽  
Armin Ehrenreich ◽  
Ralf-Jörg Fischer ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Clostridium Acetobutylicum ◽  
Wild Type ◽  
Gene Encoding ◽  
Homologous Protein ◽  
Strict Anaerobe ◽  
Genes Encoding ◽  
Highly Expressed Genes

ABSTRACT In the strict anaerobe Clostridium acetobutylicum, a PerR-homologous protein has recently been identified as being a key repressor of a reductive machinery for the scavenging of reactive oxygen species and molecular O2. In the absence of PerR, the full derepression of its regulon resulted in increased resistance to oxidative stress and nearly full tolerance of an aerobic environment. In the present study, the complementation of a Bacillus subtilis PerR mutant confirmed that the homologous protein from C. acetobutylicum acts as a functional peroxide sensor in vivo. Furthermore, we used a transcriptomic approach to analyze gene expression in the aerotolerant PerR mutant strain and compared it to the O2 stimulon of wild-type C. acetobutylicum. The genes encoding the components of the alternative detoxification system were PerR regulated. Only few other targets of direct PerR regulation were identified, including two highly expressed genes encoding enzymes that are putatively involved in the central energy metabolism. All of them were highly induced when wild-type cells were exposed to sublethal levels of O2. Under these conditions, C. acetobutylicum also activated the repair and biogenesis of DNA and Fe-S clusters as well as the transcription of a gene encoding an unknown CO dehydrogenase-like enzyme. Surprisingly few genes were downregulated when exposed to O2, including those involved in butyrate formation. In summary, these results show that the defense of this strict anaerobe against oxidative stress is robust and by far not limited to the removal of O2 and its reactive derivatives.

scholarly journals The in vivo gene expression signature of oxidative stress

2008 ◽  
Vol 34 (1) ◽  
pp. 112-126 ◽  
Author(s):  
Eun-Soo Han ◽  
Florian L. Muller ◽  
Viviana I. Pérez ◽  
Wenbo Qi ◽  
Huiyun Liang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Oxidative Damage ◽  
Target Genes ◽  
Wild Type ◽  
Antioxidant Genes ◽  
Genetic Ablation ◽  
Expression Response ◽  
P53 Target Genes

How higher organisms respond to elevated oxidative stress in vivo is poorly understood. Therefore, we measured oxidative stress parameters and gene expression alterations (Affymetrix arrays) in the liver caused by elevated reactive oxygen species induced in vivo by diquat or by genetic ablation of the major antioxidant enzymes CuZn-superoxide dismutase ( Sod1) and glutathione peroxidase-1 ( Gpx1). Diquat (50 mg/kg) treatment resulted in a significant increase in oxidative damage within 3–6 h in wild-type mice without any lethality. In contrast, treatment of Sod1−/− or Gpx1−/− mice with a similar concentration of diquat resulted in a significant increase in oxidative damage within an hour of treatment and was lethal, i.e., these mice are extremely sensitive to the oxidative stress generated by diquat. The expression response to elevated oxidative stress in vivo does not involve an upregulation of classic antioxidant genes, although long-term oxidative stress in Sod1−/− mice leads to a significant upregulation of thiol antioxidants (e.g., Mt1, Srxn1, Gclc, Txnrd1), which appears to be mediated by the redox-sensitive transcription factor Nrf2. The main finding of our study is that the common response to elevated oxidative stress with diquat treatment in wild-type, Gpx1−/−, and Sod1−/− mice and in untreated Sod1−/− mice is an upregulation of p53 target genes ( p21, Gdf15, Plk3, Atf3, Trp53inp1, Ddit4, Gadd45a, Btg2, Ndrg1). A retrospective comparison with previous studies shows that induction of these p53 target genes is a conserved expression response to oxidative stress, in vivo and in vitro, in different species and different cells/organs.

scholarly journals Identification of Gene Products Involved in the Oxidative Stress Response ofMoraxella catarrhalis

2010 ◽  
Vol 79 (2) ◽  
pp. 745-755 ◽  
Author(s):  
Todd C. Hoopman ◽  
Wei Liu ◽  
Stephanie N. Joslin ◽  
Christine Pybus ◽  
Chad A. Brautigam ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Parent Strain ◽  
Dilution Effect ◽  
Dependent Manner ◽  
Wild Type ◽  
Gene Encoding ◽  
Reverse Transcription Pcr ◽  
Genes Encoding ◽  
In The Wild ◽  
Wild Type Parent

ABSTRACTMoraxella catarrhalisis subjected to oxidative stress from both internal and environmental sources. A previous study (C. D. Pericone, K. Overweg, P. W. Hermans, and J. N. Weiser, Infect. Immun.68:3990-3997, 2000) indicated that a wild-type strain ofM. catarrhaliswas very resistant to killing by exogenous hydrogen peroxide (H2O2). The gene encoding OxyR, a LysR family transcriptional regulator, was identified and inactivated inM. catarrhalisstrain O35E, resulting in an increase in sensitivity to killing by H2O2in disk diffusion assays and a concomitant aerobic serial dilution effect. Genes encoding a predicted catalase (KatA) and an alkyl hydroperoxidase (AhpCF) showed dose-dependent upregulation in wild-type cells exposed to H2O2. DNA microarray and real-time reverse transcription-PCR (RT-PCR) analyses identifiedM. catarrhalisgenes whose expression was affected by oxidative stress in an OxyR-dependent manner. Testing ofM. catarrhalisO35EkatAandahpCmutants for their abilities to scavenge exogenous H2O2showed that the KatA catalase was responsible for most of this activity in the wild-type parent strain. The introduction of the same mutations intoM. catarrhalisstrain ETSU-4 showed that the growth of a ETSU-4katAmutant was markedly inhibited by the addition of 50 mM H2O2but that this mutant could still form a biofilm equivalent to that produced by its wild-type parent strain.

scholarly journals ENZYME ACTIVITY IN EMS-INDUCED NULL MUTATIONS OF DUPLICATED GENES ENCODING PHOSPHOGLUCOSE ISOMERASES IN CLARKIA

Genetics ◽  
1986 ◽  
Vol 113 (1) ◽  
pp. 101-114
Author(s):  
T W A Jones ◽  
E Pichersky ◽  
L D Gottlieb
Keyword(s):  
Enzyme Activity ◽  
Nuclear Gene ◽  
Activity Levels ◽  
Annual Plants ◽  
Wild Type ◽  
Gene Encoding ◽  
Regulatory Changes ◽  
Genes Encoding ◽  
Novel Method

ABSTRACT The duplication of the nuclear gene encoding the cytosolic isozyme of phosphoglucose isomerase (PGI; EC 5.3.1.9) originated within Clarkia, a genus of annual plants native to California. Previous immunological studies showed that species with and without the duplication have the same levels of cytosolic PGI activity (relative to that of the plastid PGI isozyme), as well as similar levels of cytosolic PGI protein. In the present study, we characterized seven EMS-induced null activity mutations in both duplicate PGI genes. The mutations reduced PGI activity levels in direct proportion to the normal contribution of each gene. Homozygous mutants at Pgi-3 had 64% of wild-type activity, whereas those at Pgi-2 had only 36%. The effects of the mutations at the two loci were additive, as shown by further reductions in activity in certain progeny classes in F2 progenies between them. The homozygous double null mutant class was not recovered and is presumably lethal. All of the mutants appear to be CRM+. The results account for the previously observed differences in in vivo accumulation of the duplicate isozymes in numerous Clarkia species. The results further show that PGI activity is not directly regulated by metabolic factors and suggest that the reduced PGI levels in Clarkias with the duplication probably evolved by regulatory changes in transcription or translation. The study also demonstrates a novel method to evaluate whether a particular enzyme activity is essential.

scholarly journals Characterization of a Potential Listeria monocytogenes Virulence Factor Associated with Attachment to Fresh Produce

2013 ◽  
Vol 79 (22) ◽  
pp. 6855-6861 ◽  
Author(s):  
Dongryeoul Bae ◽  
Keun Seok Seo ◽  
Ting Zhang ◽  
Chinling Wang
Keyword(s):  
Initial Study ◽  
Surface Proteins ◽  
Wild Type ◽  
Gene Encoding ◽  
Content Type ◽  
Genes Encoding ◽  
Highly Expressed Genes ◽  
Serotype 4B ◽  
Vegetables And Fruits ◽  
Cellulose Binding

ABSTRACTA study to determine the attachment ofL. monocytogenesserotype 4b strain F2365 on vegetables and fruits was conducted. In an initial study, we screened 32 genes encoding surface proteins and lipases of the strain to find highly expressed genes on lettuce leaves. The results showed that transcription levels of LMOf2365_0413, LMOf2365_0498, LMOf2365_0859, LMOf2365_2052, and LMOf2365_2812 were significantly upregulated on lettuce leaves.In silicoanalysis showed that LMOf2365_0859 contains a putative cellulose binding domain. Thus, we hypothesized that this gene may be involved in an attachment to vegetables, and named itlcp(gene encodingListeriacellulose binding protein [LCP]).lcpmutant (Δlcp) andlcpcomplement (F2365::pMAD::cat::lcp) strains were generated by homologous recombination. The abilities of a wild-type (WT) strain, the Δlcpstrain, and the complemented strain to attach to lettuce leaves were evaluated, which indicated that the attachment of the Δlcpstrain to lettuce was significantly less than that of the WT and the complemented strains. Similar results were observed for baby spinach and cantaloupe. Fluorescence microscopy and field emission scanning microscopy analysis further supported these findings. The binding ofL. monocytogenesto cellulose was determined using cellulose acetate-coated plates. The results showed that a binding ability of the Δlcpstrain was significantly lower than that of the wild type. Combined, these results strongly suggest that LCP plays an important role in an attachment to vegetables and fruits.

scholarly journals Expression and function of the cdgD gene, encoding a CHASE–PAS-DGC-EAL domain protein, in Azospirillum brasilense

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Francisco Cruz-Pérez ◽  
Roxana Lara-Oueilhe ◽  
Cynthia Marcos-Jiménez ◽  
Ricardo Cuatlayotl-Olarte ◽  
María Luisa Xiqui-Vázquez ◽  
...  
Keyword(s):  
Azospirillum Brasilense ◽  
Type Strain ◽  
Wild Type Strain ◽  
Soil Conditions ◽  
Wild Type ◽  
Gene Encoding ◽  
Wheat Roots ◽  
Genes Encoding ◽  
In The Wild ◽  
Plant Growth Promoting

AbstractThe plant growth-promoting bacterium Azospirillum brasilense contains several genes encoding proteins involved in the biosynthesis and degradation of the second messenger cyclic-di-GMP, which may control key bacterial functions, such as biofilm formation and motility. Here, we analysed the function and expression of the cdgD gene, encoding a multidomain protein that includes GGDEF-EAL domains and CHASE and PAS domains. An insertional cdgD gene mutant was constructed, and analysis of biofilm and extracellular polymeric substance production, as well as the motility phenotype indicated that cdgD encoded a functional diguanylate protein. These results were correlated with a reduced overall cellular concentration of cyclic-di-GMP in the mutant over 48 h compared with that observed in the wild-type strain, which was recovered in the complemented strain. In addition, cdgD gene expression was measured in cells growing under planktonic or biofilm conditions, and differential expression was observed when KNO3 or NH4Cl was added to the minimal medium as a nitrogen source. The transcriptional fusion of the cdgD promoter with the gene encoding the autofluorescent mCherry protein indicated that the cdgD gene was expressed both under abiotic conditions and in association with wheat roots. Reduced colonization of wheat roots was observed for the mutant compared with the wild-type strain grown in the same soil conditions. The Azospirillum-plant association begins with the motility of the bacterium towards the plant rhizosphere followed by the adsorption and adherence of these bacteria to plant roots. Therefore, it is important to study the genes that contribute to this initial interaction of the bacterium with its host plant.

Branched chain amino Acids as in vitro and in vivo Anti-Oxidation Compounds

2021 ◽  
pp. 3899-3904
Author(s):  
Moath Alqaraleh ◽  
Violet Kasabri ◽  
Ibrahim Al-Majali ◽  
Nihad Al-Othman ◽  
Nihad Al-Othman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Amino Acids ◽  
Branched Chain Amino Acids ◽  
Raw 264.7 ◽  
Raw 264.7 Cell ◽  
Branched Chain ◽  
Raw 264.7 Cell Line

Background and aims: Branched chain amino acids (BCAAs) can be tightly connected to metabolism syndrome (MetS) which can be counted as a metabolic indicator in the case of insulin resistance (IR). The aim of this study was to assess the potential role of these acids under oxidative stress. Material and Methods: the in vitro antioxidant activity of BCAAs was assessed using free radical 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging assays. For further check, a qRT-PCR technique was madefor detection the extent of alterations in gene expression of antioxidative enzymes (catalase and glutathione peroxidase (Gpx)) in lipopolysaccharides (LPS(-induced macrophages RAW 264.7 cell line. Additionally, BCAAs antioxidant activity was evaluated based on plasma H2O2 levels and xanthine oxidase (XO) activity in prooxidative LPS-treated mice. Results: Different concentrations of BCAAs affected on DPPH radical scavenging activity but to lesser extent than the ascorbic acid. Besides, BCAAs obviously upregulated the gene expression levels of catalases and Gpx in LPS-modulated macrophage RAW 264.7 cell line. In vivo BCAAs significantly minimized the level of plasma H2O2 as well as the activity of XO activity under oxidative stress. Conclusion: our current findings suggest that BCAAs supplementation may potentially serve as a therapeutic target for treatment of oxidative stress occurs with atherosclerosis, IR-diabetes, MetS and tumorigenesis.

scholarly journals Effects of Saline, an Ambient Acidic Environment, and Sodium Salicylate on OXA-Mediated Carbapenem Resistance in Acinetobacter baumannii: TABLE 1

2016 ◽  
Vol 60 (6) ◽  
pp. 3415-3418 ◽  
Author(s):  
Esther Zander ◽  
Harald Seifert ◽  
Paul G. Higgins
Keyword(s):  
Gene Expression ◽  
Acinetobacter Baumannii ◽  
Sodium Salicylate ◽  
Carbapenem Resistance ◽  
Low Ph ◽  
Wild Type ◽  
Experimental Conditions ◽  
Content Type ◽  
Reference Strains

Different physiological conditions, such as NaCl, low pH, and sodium salicylate, have been shown to affect antibiotic resistance determinants inAcinetobacter baumanniiisolates. Therefore, the aim of this study was to investigate the effects of NaCl, sodium salicylate, and low pH on the susceptibility ofA. baumanniito carbapenem. We cloned genes encoding oxacillinases (OXA) of different subclasses, with their associated promoters, from carbapenem-resistantA. baumanniiisolates into the same vector and transferred them to theA. baumanniireference strains ATCC 19606 and ATCC 17978. Carbapenem MICs were determined at least in triplicate by agar dilution under standard conditions, as well as in the presence of 200 mM NaCl or 16 mM sodium salicylate, or at pH 5.8. OXA-58-like gene expression was determined by reverse transcription-quantitative PCR (qRT-PCR). Under some experimental conditions, significant MIC reductions were shown for some transformants but not for others. Only in one instance were all transformants harboring the same OXA affected by the same condition: at pH 5.8, the imipenem and meropenem MICs for strains expressing OXA-58-like enzymes decreased from a resistant level (32 to 64 mg/liter) to an intermediate-susceptible level (8 mg/liter). However,blaOXA-58-likegene expression remained the same. MICs for both wild-type reference strains were not affected by the conditions tested. Our results indicate that the effects of the experimental conditions tested on OXAin vivoare mostly strain dependent. MICs were not reduced to wild-type levels, suggesting that the conditions tested do not lead to complete OXA inhibition in the bacterial cell.

scholarly journals WNK4 Kinase: from structure to physiology

2021 ◽  
Author(s):  
Adrian Rafael Murillo-de-Ozores ◽  
Alejandro Rodriguez-Gama ◽  
Hector Carbajal-Contreras ◽  
Gerardo Gamba ◽  
Maria Castaneda-Bueno
Keyword(s):  
Oxidative Stress ◽  
Mouse Models ◽  
Serine Threonine Kinase ◽  
Gene Encoding ◽  
Threonine Kinase ◽  
Physiological Conditions ◽  
Different Levels ◽  
Familial Hyperkalemic Hypertension

With No Lysine (K) kinase 4 (WNK4) belongs to a serine-threonine kinase family characterized by the atypical positioning of its catalytic lysine. Despite the fact that WNK4 has been found in many tissues, the majority of its study has revolved around its function in the kidney, specifically as a positive regulator of the thiazide-sensitive NaCl cotransporter (NCC) in the distal convoluted tubule (DCT) of the nephron. This is explained by the description of gain-of-function mutations in the gene encoding WNK4 that cause Familial Hyperkalemic Hypertension (FHHt). This disease is mainly driven by increased downstream activation of the Ste20-related Proline Alanine Rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1)-NCC pathway, which increases salt reabsorption in the DCT and indirectly impairs renal K+ secretion. Here, we review the large volume of information that has accumulated about different aspects of WNK4 function. We first review the knowledge on WNK4 structure and enumerate the functional domains and motifs that have been characterized. Then, we discuss WNK4 physiological functions based on the information obtained from in vitro studies and from a diverse set of genetically modified mouse models with altered WNK4 function. We then review in vitro and in vivo evidence on the different levels of regulation of WNK4. Finally, we go through the evidence that has suggested how different physiological conditions act through WNK4 to modulate NCC activity.

scholarly journals Mutant tryptophan aporepressors with altered specificities of corepressor recognition.

Genetics ◽  
1991 ◽  
Vol 128 (1) ◽  
pp. 29-35
Author(s):  
D N Arvidson ◽  
M Shapiro ◽  
P Youderian
Keyword(s):  
Dna Binding ◽  
Binding Pocket ◽  
Side Chain ◽  
Wild Type ◽  
Mutant Proteins ◽  
Naturally Occurring ◽  
Repressor Complex ◽  
Genes Encoding ◽  
Active Repressor

Abstract The Escherichia coli trpR gene encodes tryptophan aporepressor, which binds the corepressor ligand, L-tryptophan, to form an active repressor complex. The side chain of residue valine 58 of Trp aporepressor sits at the bottom of the corepressor (L-tryptophan) binding pocket. Mutant trpR genes encoding changes of Val58 to the other 19 naturally occurring amino acids were made. Each of the mutant proteins requires a higher intracellular concentration of tryptophan for activation of DNA binding than wild-type aporepressor. Whereas wild-type aporepressor is activated better by 5-methyltryptophan (5-MT) than by tryptophan, Ile58 and other mutant aporepressors prefer tryptophan to 5-MT as corepressor, and Ala58 and Gly58 prefer 5-MT much more strongly than wild-type aporepressor in vivo. These mutant aporepressors are the first examples of DNA-binding proteins with altered specificities of cofactor recognition.

scholarly journals Endothelial cell-specific reduction of heparan sulfate suppresses glioma growth in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Takamasa Kinoshita ◽  
Hiroyuki Tomita ◽  
Hideshi Okada ◽  
Ayumi Niwa ◽  
Fuminori Hyodo ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Heparan Sulfate ◽  
Vascular Endothelium ◽  
Wild Type ◽  
Brain Capillaries ◽  
Gene Encoding ◽  
Glioma Growth ◽  
Underlying Mechanisms ◽  
The Brain

Abstract Purpose Heparan sulfate (HS) is one of the factors that has been suggested to be associated with angiogenesis and invasion of glioblastoma (GBM), an aggressive and fast-growing brain tumor. However, it remains unclear how HS of endothelial cells is involved in angiogenesis in glioblastoma and its prognosis. Thus, we investigated the effect of endothelial cell HS on GBM development. Methods We generated endothelial cell-specific knockout of Ext1, a gene encoding a glycosyltransferase and essential for HS synthesis, and murine GL261 glioblastoma cells were orthotopically transplanted. Two weeks after transplantation, we examined the tumor progression and underlying mechanisms. Results The endothelial cell-specific Ext1 knockout (Ext1CKO) mice exhibited reduced HS expression specifically in the vascular endothelium of the brain capillaries compared with the control wild-type (WT) mice. GBM growth was significantly suppressed in Ext1CKO mice compared with that in WT mice. After GBM transplantation, the survival rate was significantly higher in Ext1CKO mice than in WT mice. We investigated how the effect of fibroblast growth factor 2 (FGF2), which is known as an angiogenesis-promoting factor, differs between Ext1CKO and WT mice by using an in vivo Matrigel assay and demonstrated that endothelial cell-specific HS reduction attenuated the effect of FGF2 on angiogenesis. Conclusions HS reduction in the vascular endothelium of the brain suppressed GBM growth and neovascularization in mice.

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