scholarly journals Enterococcus faecalis zinc-responsive proteins mediate bacterial defence against zinc overload, lysozyme and oxidative stress

Microbiology ◽  
2014 ◽  
Vol 160 (12) ◽  
pp. 2755-2762 ◽  
Author(s):  
Marta C. Abrantes ◽  
Jan Kok ◽  
Maria de Fátima Silva Lopes
Keyword(s):  
Oxidative Stress ◽  
Enterococcus Faecalis ◽  
Zinc Homeostasis ◽  
Binding Motif ◽  
Defence Mechanisms ◽  
Promoter Regions ◽  
Genes Encoding ◽  
High Concentrations ◽  
P Type ◽  
And Oxidative Stress

Two Enterococcus faecalis genes encoding the P-type ATPase EF1400 and the putative SapB protein EF0759 were previously shown to be strongly upregulated in the presence of high concentrations of zinc. In the present work, we showed that a Zn2+-responsive DNA-binding motif (zim) is present in the promoter regions of these genes. Both proteins were further studied with respect to their involvement in zinc homeostasis and invasion of the host. EF0759 contributed to intramacrophage survival by an as-yet unknown mechanism(s). EF1400, here renamed ZntAEf, is an ATPase with specificity for zinc and plays a role in dealing with several host defences, i.e. zinc overload, oxidative stress and lysozyme; it provides E. faecalis cells with the ability to survive inside macrophages. As these three host defence mechanisms are important at several sites in the host, i.e. inside macrophages and in saliva, this work suggested that ZntAEf constitutes a crucial E. faecalis defence mechanism that is likely to contribute to the ability of this bacterium to endure life inside its host.

scholarly journals Effect of fish meal replacement by plant protein sources on non-specific defence mechanisms and oxidative stress in gilthead sea bream (Sparus aurata)

Aquaculture ◽  
2005 ◽  
Vol 249 (1-4) ◽  
pp. 387-400 ◽  
Author(s):  
A. Sitjà-Bobadilla ◽  
S. Peña-Llopis ◽  
P. Gómez-Requeni ◽  
F. Médale ◽  
S. Kaushik ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Fish Meal ◽  
Sparus Aurata ◽  
Sea Bream ◽  
Meal Replacement ◽  
Defence Mechanisms ◽  
Protein Sources ◽  
Plant Protein Sources ◽  
Fish Meal Replacement ◽  
And Oxidative Stress

scholarly journals Cooption of heat shock regulatory system for anhydrobiosis in the sleeping chironomid Polypedilum vanderplanki

2018 ◽  
Vol 115 (10) ◽  
pp. E2477-E2486 ◽  
Author(s):  
Pavel V. Mazin ◽  
Elena Shagimardanova ◽  
Olga Kozlova ◽  
Alexander Cherkasov ◽  
Roman Sutormin ◽  
...  
Keyword(s):  
Heat Shock ◽  
Gene Activation ◽  
Regulatory System ◽  
Late Embryogenesis Abundant ◽  
Binding Motif ◽  
Transcription Activator ◽  
Promoter Regions ◽  
Genes Encoding ◽  
Polypedilum Vanderplanki ◽  
The Sleeping Chironomid

Polypedilum vanderplanki is a striking and unique example of an insect that can survive almost complete desiccation. Its genome and a set of dehydration–rehydration transcriptomes, together with the genome of Polypedilum nubifer (a congeneric desiccation-sensitive midge), were recently released. Here, using published and newly generated datasets reflecting detailed transcriptome changes during anhydrobiosis, as well as a developmental series, we show that the TCTAGAA DNA motif, which closely resembles the binding motif of the Drosophila melanogaster heat shock transcription activator (Hsf), is significantly enriched in the promoter regions of desiccation-induced genes in P. vanderplanki, such as genes encoding late embryogenesis abundant (LEA) proteins, thioredoxins, or trehalose metabolism-related genes, but not in P. nubifer. Unlike P. nubifer, P. vanderplanki has double TCTAGAA sites upstream of the Hsf gene itself, which is probably responsible for the stronger activation of Hsf in P. vanderplanki during desiccation compared with P. nubifer. To confirm the role of Hsf in desiccation-induced gene activation, we used the Pv11 cell line, derived from P. vanderplanki embryo. After preincubation with trehalose, Pv11 cells can enter anhydrobiosis and survive desiccation. We showed that Hsf knockdown suppresses trehalose-induced activation of multiple predicted Hsf targets (including P. vanderplanki-specific LEA protein genes) and reduces the desiccation survival rate of Pv11 cells fivefold. Thus, cooption of the heat shock regulatory system has been an important evolutionary mechanism for adaptation to desiccation in P. vanderplanki.

scholarly journals Oxidative Stress Sensor Keap1 Functions as an Adaptor for Cul3-Based E3 Ligase To Regulate Proteasomal Degradation of Nrf2

2004 ◽  
Vol 24 (16) ◽  
pp. 7130-7139 ◽  
Author(s):  
Akira Kobayashi ◽  
Moon-Il Kang ◽  
Hiromi Okawa ◽  
Makiko Ohtsuji ◽  
Yukari Zenke ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Proteins ◽  
E3 Ligase ◽  
Genes Encoding ◽  
Cullin 3 ◽  
Ubiquitin Proteasome ◽  
A Subunit ◽  
Antioxidant Stress ◽  
And Oxidative Stress

ABSTRACT Transcription factor Nrf2 is a major regulator of genes encoding phase 2 detoxifying enzymes and antioxidant stress proteins in response to electrophilic agents and oxidative stress. In the absence of such stimuli, Nrf2 is inactive owing to its cytoplasmic retention by Keap1 and rapid degradation through the proteasome system. We examined the contribution of Keap1 to the rapid turnover of Nrf2 (half-life of less than 20 min) and found that a direct association between Keap1 and Nrf2 is required for Nrf2 degradation. In a series of domain function analyses of Keap1, we found that both the BTB and intervening-region (IVR) domains are crucial for Nrf2 degradation, implying that these two domains act to recruit ubiquitin-proteasome factors. Indeed, Cullin 3 (Cul3), a subunit of the E3 ligase complex, was found to interact specifically with Keap1 in vivo. Keap1 associates with the N-terminal region of Cul3 through the IVR domain and promotes the ubiquitination of Nrf2 in cooperation with the Cul3-Roc1 complex. These results thus provide solid evidence that Keap1 functions as an adaptor of Cul3-based E3 ligase. To our knowledge, Nrf2 and Keap1 are the first reported mammalian substrate and adaptor, respectively, of the Cul3-based E3 ligase system.

scholarly journals Antibacterial Action of Polyphosphate onPorphyromonas gingivalis

2010 ◽  
Vol 55 (2) ◽  
pp. 806-812 ◽  
Author(s):  
Ji-Hoi Moon ◽  
Jae-Hong Park ◽  
Jin-Yong Lee
Keyword(s):  
Oxidative Stress ◽  
Inoculum Size ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Iron Storage ◽  
Gram Negative ◽  
Dense Granules ◽  
Genes Encoding ◽  
Atypical Cells ◽  
And Oxidative Stress

ABSTRACTPolyphosphate [poly(P)] has antibacterial activity against various Gram-positive bacteria. In contrast, Gram-negative bacteria are generally resistant to poly(P). Here, we describe the antibacterial characterization of poly(P) against a Gram-negative periodontopathogen,Porphyromonas gingivalis. The MICs of pyrophosphate (Na4P2O7) and all poly(P) (Nan+ 2PnO3n+ 1;n= 3 to 75) tested for the bacterium by the agar dilution method were 0.24% and 0.06%, respectively. Orthophosphate (Na2HPO4) failed to inhibit bacterial growth. Poly-P75 was chosen for further study. In liquid medium, 0.03% poly-P75 was bactericidal againstP. gingivalisirrespective of the growth phase and inoculum size, ranging from 105to109cells/ml. UV-visible spectra of the pigments fromP. gingivalisgrown on blood agar with or without poly-P75 showed that poly-P75 reduced the formation of μ-oxo bisheme by the bacterium. Poly-P75 increased hemin accumulation on theP. gingivalissurface and decreased energy-driven uptake of hemin by the bacterium. The expression of the genes encoding hemagglutinins, gingipains, hemin uptake loci, chromosome replication, and energy production was downregulated, while that of the genes related to iron storage and oxidative stress was upregulated by poly-P75. The transmission electron microscope showed morphologically atypical cells with electron-dense granules and condensed nucleoid in the cytoplasm. Collectively, poly(P) is bactericidal againstP. gingivalis, in which hemin/heme utilization is disturbed and oxidative stress is increased by poly(P).

Analysis of Gene Expression in Response to Copper Stress in Acidithiobacillus ferrooxidans Strain D2, Isolated from a Copper Bioleaching Operation

2013 ◽  
Vol 825 ◽  
pp. 157-161 ◽  
Author(s):  
Camila N. Salazar ◽  
Mauricio Acosta ◽  
Pedro A. Galleguillos ◽  
Amir Shmaryahu ◽  
Raquel Quatrini ◽  
...  
Keyword(s):  
Stress Response ◽  
Acidithiobacillus Ferrooxidans ◽  
Dna Microarrays ◽  
Copper Stress ◽  
Molecular Response ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
High Concentrations ◽  
P Type ◽  
Upregulated Genes

Acidithiobacillus ferrooxidans strain D2 was isolated from a copper bioleaching operation in Atacama Desert, Chile. Copper is widely used as cofactor in proteins but high concentrations of copper are toxic. Cells require certain mechanisms to maintain the copper homeostasis and avoid toxic effects of high intracellular concentration. The molecular response of A. ferrooxidans strain D2 grown in the presence/absence of copper was examined using a A. ferrooxidans whole-genome DNA microarrays. Roughly 23% of 3,147 genes represented on the microarray were differentially expressed; about 9% of them were upregulated in the presence of copper. Among the upregulated genes, those encoding for the copper efflux protein (CusA) and for the copper-translocating P-type ATPase (CopA) were upregulated. The expression of genes encoding proteins related to iron transport was repressed. Similarly, genes related with assimilative metabolism of sulfur (L-cysteine biosynthesis) cysB, cysJ, cysI, CysD-2 and cysN were upregulated. Our results show that when A. ferrooxidans strain D2 was challenged with high copper concentrations, genes related to copper stress response were upregulated as well as others that have not been reported to be related to that mechanism. In addition, some genes related to other metabolic pathways were repressed, probably because of the energy cost of the stress response.

ROLE OF PREGNAN-X-RECEPTOR IN CELL RESISTANCE TO NITROSATIVE AND OXIDATIVE STRESS

2021 ◽  
Author(s):  
Yulia Abalenikhina ◽  
◽  
Elena A. Sudakova ◽  
Pelageya Erokhina ◽  
Aleksey Shchulkin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cell Viability ◽  
Nitrosative Stress ◽  
Pregnane X Receptor ◽  
Cell Resistance ◽  
Oxidative And Nitrosative Stress ◽  
High Concentrations ◽  
And Oxidative Stress

The article discusses the new role of pregnane X receptor (PXR) under conditions of oxidative and nitrosative stress. The results showed that the effect of hydrogen peroxide and S-nitrosoglu-tathione in high concentrations on Caco-2 cells leads to a decrease in cell viability, which is accompanied by an increase in the amount of PXR. These changes are offset by the addition of ketoconazole (inhibitor of PXR) to the medium.

scholarly journals Effects of Oxygen on Renal Function and Oxidative Stress During Hypothermic Machine Perfusion in an Experimental Porcine Model of Kidney Donation after Cardiac Death

2020 ◽  
Vol 05 (02) ◽  
pp. 1-1
Author(s):  
Victoria Gómez-Dos-Santos ◽  
◽  
Vital Hevia Palacios ◽  
María Laura García Bermejo ◽  
Alberto Alcázar González ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Renal Function ◽  
Epithelial Mesenchymal Transition ◽  
Machine Perfusion ◽  
Mesenchymal Transition ◽  
Hypothermic Machine Perfusion ◽  
Atp Generation ◽  
High Concentrations ◽  
And Oxidative Stress

The efficacy and safety of using high concentrations of oxygen during hypothermic machine perfusion (HMP) have not been fully elucidated to date. This study investigated the impact of administering high concentrations of oxygen on renal function during HMP in a porcine donation after circulatory death (DCD), as well as the metabolic and biochemical effects of this method. A randomized nonblinded cohort study was established in a porcine transplant (KT) model mimicking Maastricht type III DCD under oxygen-supplemented HMP (Ox-HMP) compared to non-supplemented (nOx-HMP) (LifePort® kidney transporter) conditions. The primary endpoint was evolution of renal function post-KT, whereas secondary endpoints included changes in perfusion dynamics, miRNA expression and cellular lesion measured by LDH and lactate levels in perfusate, lipid peroxidation in kidney biopsies, ATP generation, epithelial mesenchymal transition (EMT) and oxidative gene expression in cell cultures and histology evaluation. ATP generation and oxidative stress, as measured by lipid peroxidation, increased simultaneously after warm ischemia in the Ox-HMP group. Ox-HMP did not exhibit a significant effect on kidney function or animal survival. A significant increase in lipid peroxidation was observed in the Ox-HMP group. This resulted in a greater expression of the genes responsible for producing superoxide dismutase 1 (SOD-1) and catalase oxygenation enzymes, although only SOD-1 showed statistical significance. Respiratory chain dysfunction was maintained in the Ox-HMP group with a non-significant decrease in ATP production, increased proton leakage, and a decrease in respiratory reserve. Regarding epithelial-mesenchymal transition, an upward trend in the expression of vimentin, fibronectin, and collagen genes was observed only in the Ox-HMP group. Finally, the expression levels of miR-101 and miR-126, related to characteristic functions of the tubular epithelium, were significantly modified (miRNA levels expressed as DCT. A brief bubble Ox-HMP treatment did not show a clear positive effect on renal function and oxidative stress markers. The role and safety of adding oxygen during HMP still need to be elucidated. Currently, this Ox-HMP method cannot be considered standard practice.

scholarly journals Unlocking Survival Mechanisms for Metal and Oxidative Stress in the Extremely Acidophilic, Halotolerant Acidihalobacter Genus

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1392
Author(s):  
Himel Nahreen Khaleque ◽  
Homayoun Fathollazadeh ◽  
Carolina González ◽  
Raihan Shafique ◽  
Anna H. Kaksonen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Metal Tolerance ◽  
Acid Stress ◽  
Copper Resistance ◽  
Bioinformatic Tools ◽  
Multiple Strategies ◽  
Wide Range ◽  
Genes Encoding ◽  
Genomic Cluster ◽  
And Oxidative Stress

Microorganisms used for the biohydrometallurgical extraction of metals from minerals must be able to survive high levels of metal and oxidative stress found in bioleaching environments. The Acidihalobacter genus consists of four species of halotolerant, iron–sulfur-oxidizing acidophiles that are unique in their ability to tolerate chloride and acid stress while simultaneously bioleaching minerals. This paper uses bioinformatic tools to predict the genes and mechanisms used by Acidihalobacter members in their defense against a wide range of metals and oxidative stress. Analysis revealed the presence of multiple conserved mechanisms of metal tolerance. Ac. yilgarnensis F5T, the only member of this genus that oxidizes the mineral chalcopyrite, contained a 39.9 Kb gene cluster consisting of 40 genes encoding mobile elements and an array of proteins with direct functions in copper resistance. The analysis also revealed multiple strategies that the Acidihalobacter members can use to tolerate high levels of oxidative stress. Three of the Acidihalobacter genomes were found to contain genes encoding catalases, which are not common to acidophilic microorganisms. Of particular interest was a rubrerythrin genomic cluster containing genes that have a polyphyletic origin of stress-related functions.

scholarly journals Improving the effect of incubation and oxidative stress on thawed spermatozoa from red deer by using different antioxidant treatments

2010 ◽  
Vol 22 (5) ◽  
pp. 856 ◽  
Author(s):  
Álvaro E. Domínguez-Rebolledo ◽  
María R. Fernández-Santos ◽  
Alfonso Bisbal ◽  
José Luis Ros-Santaella ◽  
Manuel Ramón ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Lipoic Acid ◽  
Mitochondrial Membrane ◽  
Red Deer ◽  
Intracellular Reactive Oxygen Species ◽  
Oxygen Species ◽  
Positive Effects ◽  
High Concentrations ◽  
And Oxidative Stress

Antioxidants could improve sperm media, extending the viability of spermatozoa and protecting their DNA. The protective ability of lipoic acid, melatonin, Trolox and crocin was tested on red deer spermatozoa incubated at 37°C. Cryopreserved spermatozoa were thawed and incubated with 1 mM or 0.1 mM of each antioxidant, with or without oxidative stress (100 μM Fe2+). Motility (CASA), viability, mitochondrial membrane potential and acrosomal status were assessed. Lipoperoxidation (malondialdehyde production), intracellular reactive oxygen species (ROS) and DNA status (TUNEL) were checked at 4 h. Incubation alone increased ROS and decreased motility. Oxidative stress intensified these effects, increasing lipoperoxidation and DNA damage. Lipoic acid had little protective effect, whereas 1 mM melatonin showed limited protection. Trolox lowered ROS and lipoperoxidation both in oxidised and non-oxidised samples. In oxidised samples, Trolox prevented DNA and acrosomal damage, and ameliorated motility. Crocin at 1 mM showed similar results to Trolox, but noticeably stimulated motility and had no effect on lipoperoxidation. In a second experiment, a broader range of crocin and melatonin concentrations were tested, confirming the effects of crocin (positive effects noticeable at 0.5–0.75 mM), but showing an increase in lipoperoxidation at 2 mM. Melatonin was increasingly effective at 2.5 and 5 mM (ROS, lipoperoxidation and DNA status). Crocin seems a promising new antioxidant, but its particular effects on sperm physiology must be further studied, especially the consequences of motility stimulation and confirming its effect on lipoperoxidation. Melatonin might be useful at relatively high concentrations, compared to Trolox.

scholarly journals Caenorhabditis elegansPMR1, a P-type calcium ATPase, is important for calcium/manganese homeostasis and oxidative stress response

FEBS Letters ◽  
2004 ◽  
Vol 579 (3) ◽  
pp. 778-782 ◽  
Author(s):  
Jeong Hoon Cho ◽  
Kyung Min Ko ◽  
Gunasekaran Singaravelu ◽  
Joohong Ahnn
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Oxidative Stress Response ◽  
Calcium Atpase ◽  
P Type ◽  
And Oxidative Stress
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