Removal Of Reactive Oxygen Species Research Articles

G6PD deficiency: imbalance of functional dichotomy contributing to the severity of COVID-19.

Human COVID-19 has affected more than 491 million people worldwide. It has caused over 6.1 million deaths and has especially perpetrated a high number of casualties among the elderly and those with comorbid illnesses. COVID-19 triggers a pro-oxidant response, leading to the production of reactive oxygen species (ROS) as a common innate defense mechanism. However, ROS are regulated by a key enzyme called G6PD via the production of reduced nicotinamide adenine dinucleotide phosphate (NADPH), which controls the generation and removal of ROS in a tissue-specific manner. Therefore, a deficiency of G6PD can lead to the dysregulation of ROS, which causes a severe inflammatory response in COVID-19 patients. This report highlights the G6PD dichotomy in the regulation of ROS and inflammatory responses, as well as its deficiency in severity among COVID-19 patients.

Sarmentosin promotes USP17 and regulates Nrf2-mediated mitophagy and cellular oxidative stress to alleviate APAP-induced acute liver failure

BackgroundAn overdose of acetaminophen (APAP), the main cause of acute liver failure (ALF), induces oxidative stress that ultimately causes mitochondrial impairment and hepatotoxicity. The nuclear factor erythroid 2-related factor 2 (Nrf2) was widely recognized as an anti-oxidative stress mechanism. The present study was aimed at investigating whether sarmentosin, extract from traditional Chinese medicine, protects the liver against APAP-induced injury via activating Nrf2 and subsequently decreasing oxidative stress. MethodsMale ICR mice were treated with sarmentosin oral administration for 1 week and injected APAP (300 mg/kg. i.p.) for acute liver injury model. The liver and serum of mice for histological and biochemistry analysis. AML12 and LO2 cells were used in vitro assays. ResultsWe found that sarmentosin moderately increased accumulation of Nrf2 via upregulating USP17-mediated ubiquitin inhibition at the early stage of hepatocytes damage. The Nrf2 separating from bonding protein Keap1 translocated into nucleus and activated downstream gene of antioxidants. Mitophagy, a unique autophagy can remove Reactive Oxygen Species (ROS) damaged mitochondria, was elevated in this progress to maintain mitochondria function and ROS homeostasis. ConclusionIn summary, our research revealed that sarmentosin could alleviate APAP-induced liver acute injury through USP17-mediated Nrf2 overexpression and PINK1-dependent mitophagy.

Antioxidant System and Ions Concentrations After Femoral Neck and Resurfacing Hip Arthroplasty.

BackgroundOxidative stress is a disruption of the pro-oxidative-antioxidant balance, caused by excessive production or ineffective removal of reactive oxygen species.Material/MethodsThe study included 42 male patients aged 38 to 69 years. The first group consisted of 21 men with osteoarthritis after primary hip arthroplasty using the Smith & Nephew Birmingham Hip Resurfacing implant. The second group included 21 men after hip arthroplasty using the femoral neck SPIRON K-implant. In both groups, concentrations of ions, the antioxidant system in the blood, and parameters of oxidative stress were evaluated twice. Clinical assessment using the Western Ontario and McMaster Universities Osteoarthritis Index, Harris Hip Score, and Short Form (12) Health Survey (SF-12) scales was performed.ResultsConcentrations of metal ions in the blood and the level of oxidative stress were significantly higher in the resurfacing group than in the femoral neck arthroplasty group. The response of the antioxidant system was significantly greater in the femoral neck arthroplasty group. During clinical evaluation, groups did not show significant differences, with the exception of greater shortening of the operated limb and a lower score in the mental-sphere of the SF-12 scale in the resurfacing arthroplasty group.ConclusionsResurfacing hip arthroplasty increased oxidative stress, increased the concentration of metal ions, and did not affect alignment of the abbreviation of the operated limb. A significant improvement in the quality of life of patients in the mental sphere according to the SF-12 occurred after the application of resurfacing arthroplasty, in the first month after the procedure.

Bioremediation potential of hexavalent chromium-resistant Arthrobacter globiformis 151B: study of the uptake of cesium and other alkali ions.

Cesium (Cs+) enters environments largely because of global release into the environment from weapons testing and accidents such as Fukushima Daiichi and Chernobyl nuclear waste. Even at low concentrations, Cs+ is highly toxic to ecological receptors because of its physicochemical similarity to macronutrient potassium (K+). We investigated the uptake and accumulation of Cs+ by Arthrobacter globiformis strain 151B in reference to three similar alkali metal cations rubidium (Rb+), sodium (Na+), and potassium (K+). The impact of hexavalent chromium (Cr+6) as a co-contaminant was also evaluated. A. globiformis 151B accumulated Cs+ and Cr6+ in a time-dependent fashion. In contrast, the uptake and accumulation of Rb+ did not exhibit any trends. An exposure to Cs+, Rb+, and Cr+6 triggered a drastic increase in K+ and Na+ uptake by the bacterial cells. That was followed by the efflux of K+ and Na+, suggesting a Cs+ "substitution." Two-dimensional gel-electrophoresis of bacterial cell proteomes with the following mass-spectrometry of differentially expressed bands revealed that incubation of bacterial cells with Cs+ induced changes in the expression of proteins involved in the maintenance of cellular homeostasis and reactive oxygen species removal. The ability of A. globiformis 151B to mediate the uptake and accumulation of cesium and hexavalent chromium suggests that it possesses wide-range bioremediation potential.

Melatonin mediates reactive oxygen species homeostasis via SlCV to regulate leaf senescence in tomato plants.

Melatonin (MT) functions in removing reactive oxygen species (ROS) and delaying plant senescence, thereby acting as an antioxidant; however, the molecular mechanism underlying the specific action of MT is unclear. Herein, we used the mutant plants carrying the MT decomposition gene melatonin 3-hydroxylase (M3H) in tomatoto elucidate the specific mechanism of action of MT. SlM3H-OE accelerated senescence by decreasing the content of endogenous MT in plants. SlM3H is a senescence-related gene that positively regulates aging. MT inhibited the expression of the senescence-related gene SlCV to scavenge ROS, induced stable chloroplast structure, and delayed leaf senescence. Simultaneously, MT weakened the interaction between SlCV and SlPsbO/SlCAT3, reduced ROS production in photosystem II, and promoted ROS elimination. In conclusion, MT regulates ROS homeostasis and delays leaf agingin tomato plants through SlCV expression modulation.

Genome-Wide Characterization of Superoxide Dismutase (SOD) Genes in Daucus carota: Novel Insights Into Structure, Expression, and Binding Interaction With Hydrogen Peroxide (H2O2) Under Abiotic Stress Condition.

Superoxide dismutase (SOD) proteins are important antioxidant enzymes that help plants to grow, develop, and respond to a variety of abiotic stressors. SOD gene family has been identified in a number of plant species but not yet in Daucus carota. A total of 9 DcSOD genes, comprising 2 FeSODs, 2 MnSODs, and 5 Cu/ZnSODs, are identified in the complete genome of D. carota, which are dispersed in five out of nine chromosomes. Based on phylogenetic analysis, SOD proteins from D. carota were categorized into two main classes (Cu/ZnSODs and MnFeSODs). It was predicted that members of the same subgroups have the same subcellular location. The phylogenetic analysis was further validated by sequence motifs, exon–intron structure, and 3D protein structures, with each subgroup having a similar gene and protein structure. Cis-regulatory elements responsive to abiotic stresses were identified in the promoter region, which may contribute to their differential expression. Based on RNA-seq data, tissue-specific expression revealed that DcCSD2 had higher expression in both xylem and phloem. Moreover, DcCSD2 was differentially expressed in dark stress. All SOD genes were subjected to qPCR analysis after cold, heat, salt, or drought stress imposition. SODs are antioxidants and play a critical role in removing reactive oxygen species (ROS), including hydrogen peroxide (H2O2). DcSODs were docked with H2O2 to evaluate their binding. The findings of this study will serve as a basis for further functional insights into the DcSOD gene family.

Sustainability of in vitro light-dependent NADPH generation by the thylakoid membrane of Synechocystis sp. PCC6803

BackgroundNADPH is used as a reductant in various biosynthetic reactions. Cell-free bio-systems have gained considerable attention owing to their high energy utilization and time efficiency. Efforts have been made to continuously supply reducing power to the reaction mixture in a cyclical manner. The thylakoid membrane (TM) is a promising molecular energy generator, producing NADPH under light. Thus, TM sustainability is of major relevance for its in vitro utilization.ResultsOver 70% of TMs prepared from Synechocystis sp. PCC6803 existed in a sealed vesicular structure, with the F1 complex of ATP synthase facing outward (right-side-out), producing NADPH and ATP under light. The NADPH generation activity of TM increased approximately two-fold with the addition of carbonyl cyanide-p-(trifluoromethoxy) phenylhydrazone (FCCP) or removal of the F1 complex using EDTA. Thus, the uncoupling of proton translocation from the electron transport chain or proton leakage through the Fo complex resulted in greater NADPH generation. Biosilicified TM retained more than 80% of its NADPH generation activity after a week at 30°C in the dark. However, activity declined sharply to below 30% after two days in light. The introduction of engineered water-forming NADPH oxidase (Noxm) to keep the electron transport chain of TM working resulted in the improved sustainability of NADPH generation activity in a ratio (Noxm to TM)-dependent manner, which correlated with the decrease of singlet oxygen generation. Removal of reactive oxygen species (ROS) by catalase further highlighted the sustainable NADPH generation activity of up to 80% in two days under light.ConclusionReducing power generated by light energy has to be consumed for TM sustainability. Otherwise, TM can generate singlet oxygen, causing oxidative damage. Thus, TMs should be kept in the dark when not in use. Although NADPH generation activity by TM can be extended via silica encapsulation, further removal of hydrogen peroxide results in an improvement of TM sustainability. Therefore, as long as ROS formation by TM in light is properly handled, it can be used as a promising source of reducing power for in vitro biochemical reactions.Graphical

Physiological and Transcriptomic Comparison of Two Sunflower (Helianthus annuus L.) Cultivars With High/Low Cadmium Accumulation

The toxic heavy metal cadmium (Cd) is easily absorbed and accumulated in crops and affects human health through the food chains. Sunflower (Helianthus annuus L.) is a globally important oil crop. In this study, two sunflower cultivars 62\\3 (high Cd) and JB231AC (low Cd), were chosen to compare physiological and transcriptomic responses at different Cd concentrations (0, 25, 50, and 100 μM). The results showed that JB231AC had better Cd tolerance than 62\\3. The contents of H2O2 and MDA (malondialdehyde) in 62\\3 were lower than that in JB231AC under Cd stress, but the activities of SOD (superoxide dismutase) and POD (peroxidase) in JB231AC were higher than in 62\\3, which indicated that JB231AC had a strong ability to remove reactive oxygen species (ROS)-induced toxic substances. Many deferentially expressed ABC (ATP-binding cassette) and ZIP (Zn-regulated transporter, Iron-regulated transporter-like protein) genes indicated that the two gene families might play important roles in different levels of Cd accumulation in the two cultivars. One up-regulated NRAMP (Natural resistance-associated macrophage protein) gene was identified and had a higher expression level in 62\\3. These results provide valuable information to further understand the mechanism of Cd accumulation and provide insights into breeding new low Cd sunflower cultivars.

Anthocyanin regulatory networks in Solanum tuberosum L. leaves elucidated via integrated metabolomics, transcriptomics, and StAN1 overexpression

BackgroundAnthocyanins, which account for color variation and remove reactive oxygen species, are widely synthesized in plant tissues and organs. Using targeted metabolomics and nanopore full-length transcriptomics, including differential gene expression analysis, we aimed to reveal potato leaf anthocyanin biosynthetic pathways in different colored potato varieties.ResultsMetabolomics analysis revealed 17 anthocyanins. Their levels varied significantly between the different colored varieties, explaining the leaf color differences. The leaves of the Purple Rose2 (PurpleR2) variety contained more petunidin 3-O-glucoside and malvidin 3-O-glucoside than the leaves of other varieties, whereas leaves of Red Rose3 (RedR3) contained more pelargonidin 3-O-glucoside than the leaves of other varieties. In total, 114 genes with significantly different expression were identified in the leaves of the three potato varieties. These included structural anthocyanin synthesis–regulating genes such as F3H, CHS, CHI, DFR, and anthocyanidin synthase and transcription factors belonging to multiple families such as C3H, MYB, ERF, NAC, bHLH, and WRKY. We selected an MYB family transcription factor to construct overexpression tobacco plants; overexpression of this factor promoted anthocyanin accumulation, turning the leaves purple and increasing their malvidin 3-o-glucoside and petunidin 3-o-glucoside content.ConclusionsThis study elucidates the effects of anthocyanin-related metabolites on potato leaves and identifies anthocyanin metabolic network candidate genes.

Dietary Bioflavanol Supplementation Does Not Improve Cold‐Induced Vasodilation in Healthy Adults

BackgroundCold‐induced vasodilation (CIVD) is a cyclical rise in blood flow to glabrous skin that occurs during cold exposure of the extremities. Nitric oxide (NO) is a proposed mediator of the CIVD response through active vasodilation and/or withdrawal of sympathetic vascular smooth muscle tone. Dietary flavanols augment bioavailable NO by upregulating NO synthase, the main source of NO in the vasculature, and by enhancing removal of reactive oxygen species that are known to breakdown NO. Although acute dietary flavanol intake has been shown to augment skin blood flow, at least in part through increased NO, no studies have examined the impact of flavanol intake on skin perfusion during cold exposure. Improving skin blood flow to the extremities may enhance manual dexterity and reduce the risk of peripheral cold injury, benefits pertinent to warfighters or other populations that spend time in cold environments.PurposeTo examine the effect of high‐dose flavanol supplementation on CIVD. We hypothesized that acute and 8‐day flavanol supplementation would augment CIVD during single‐digit cold water immersion.MethodsEleven healthy adults (24±6 yrs; 10M/1F) ingested cocoa‐based flavanols (FLV; 900 mg/d) or caffeine and theobromine‐matched placebo (PLA) for 8 days in a double‐blind, randomized, crossover design. On Days 1 and 8, CIVD was assessed 2 hours after treatment ingestion. Subjects immersed their middle finger in warm water (42°C) for 15 minutes before cold water immersion (4°C) for 30 min, during which nail bed and finger pad skin temperature were measured continuously.ResultsFlavanol ingestion had no effect (all P > 0.05) on CIVD event frequency (Day 1, FLV: 3±2 vs. PLA: 3±2; Day 8, FLV: 3±2 vs. PLA: 3±1) or amplitude (Day 1, FLV: 4.3±1.7 vs. PLA: 4.9±2.6 °C; Day 8, FLV: 3.9±1.9 vs. PLA: 3.9±2.0 °C) in the finger pad following acute or 8‐day supplementation. Furthermore, average (Day 1, FLV: 9.2±1.5 vs. PLA: 9.2±1.8 °C; Day 8, FLV: 8.3±1.7 vs. PLA: 8.9±1.9 °C), maximum (Day 1, FLV: 11.9±3.0 vs. PLA: 11.2±2.3 °C; Day 8, FLV: 10.1±1.9 vs. PLA: 10.6±2.3 °C), and minimum (Day 1, FLV: 6.2±1.3 vs. PLA: 6.0±1.5 °C; Day 8, FLV: 5.8±1.8 vs. PLA: 6.2±1.7 °C) finger pad temperatures during cold water immersion were not different (all P > 0.05) between treatments on Day 1 or Day 8 of supplementation. Similarly, no differences (all P > 0.05) in CIVD parameters were observed in the nail bed following acute or 8‐day supplementation.ConclusionDietary ingestion of cocoa‐based flavanols does not improve the CIVD response to single‐digit cold water immersion.

Silicon enhances the submergence tolerance of rice by regulating quiescence strategy and alleviating oxidative damage

The safety of rice production under submergence is one of the research hotspots worldwide. Although the effects of silicon (Si) on enhancing plant stress tolerance have been widely investigated, the underlying mechanisms mediated by Si under submergence remains poorly understood. In this study, wild type (WT) and Si-defective mutant (lsi1) rice were chosen to investigate the mechanisms of Si-mediated rice resistance to submergence. Our results showed that Si addition effectively mitigated oxidative damages under submergence by reducing the content of hydrogen peroxide (H2O2) and superoxide (O2.-) in WT rice plants. Moreover, Si treatment increased rice yield by 21.5% for WT rice under submergence. The application of Si significantly inhibited the elongation and internode length in WT rice under submergence, through the synergistic regulation of endogenous hormones ethylene (ET), gibberellic acid (GA) and jasmonic acid (JA). Further investigation showed that the ethylene-responsive factor (ERF) SUB1A gene was expressed under submergence in WT and lsi1 rice, but Si addition did not influence the expression of SUB1A. Interestingly, exogenous Si down-regulated the relative expression levels of Si transporter genes Lsi1 and Lsi2 in WT rice roots by 51.7% and 48.0%, respectively. However, the physiological characteristics and genes expression of lsi1 rice were not affected by Si application regardless of submergence. The present study indicated that Si enhances the submergence tolerance and reduce the adverse effects of yield loss through the removal of reactive oxygen species and the adjustment of quiescence strategy.

Superior Adhesion of a Multifunctional Protein-Based Micropatch to Intestinal Tissue by Harnessing the Hydrophobic Effect.

Drug delivery systems comprising drug carriers capable of adhering to intestinal tissue have considerable potential to realize more sophisticated systemic drug delivery and topical drug treatments in the intestinal tract. The development of innovative strategies for improving the adhesion efficiency of carriers is of high importance for the advancement of this field. Herein, a novel approach to achieving high adhesion efficiency of drug carriers is presented, where the accessibility of the carrier to the intestinal surface and its subsequent adhesion to the intestinal tissue are promoted by utilizing the thermodynamic tendency of the hydrophobic carrier and its dispersion solvent, triacetin, to be excluded from the aqueous environment. Drug carriers are fabricated using proteins, imparting multiple functions, including drug release and the removal of reactive oxygen species (ROS). Results of ex vivo studies indicate that this multifunctional protein-based carrier, "protein micropatch," adheres to various mouse intestinal tissues, including the small intestine, colon, and inflamed colon, with high efficiency. Furthermore, protein micropatches, administered to mice via oral or rectal routes, successfully adhere to the intestinal tract. This approach and the highly functionalized carrier described in the study have the potential to significantly contribute to the development of bioadhesive carrier-based drug delivery systems.

High-efficiency biofuel production by mixing seawater and domestic sewage to culture freshwater microalgae

Although microalgae biofuel has many advantages, its production is faced with difficulties regarding algal cell harvesting and low lipid content. In this experiment, mixtures of seawater and domestic sewage were prepared for the cultivation of freshwater microalgae. The results showed that the proportion of seawater had an important effect on the precipitation and biofuel production of the microalgae. The increasing proportion of seawater in the mixed wastewater improved the sedimentation performance and lipid content of microalgae, but the growth of microalgae was greatly inhibited under 80% seawater stress. Therefore, the highest algal lipid productivity of 10.74 mg L-1 d-1 was achieved in the wastewater containing 60% seawater, which was 2.15-fold higher than that of the control. Furthermore, the fatty acid saturation and the C16-C18 fatty acid proportion of the microalgae cultured in wastewater containing 60% seawater were relatively ideal, which was beneficial for improving the quality of biodiesel. Therefore, wastewater containing 60% seawater was the most favourable for the cultivation of biofuel-producing microalgae. The mechanism by which seawater improved the precipitation performance of freshwater microalgae was also investigated. The addition of seawater to the sewage increased the cell diameter of the microalgae, reduced the zeta potential of microalgal colloids, and promoted the synthesis of extracellular polymeric substances by the microalgal cells. Thus, the precipitation performance of the microalgae cells was effectively improved. The pigment contents and antioxidant enzyme activities of the microalgae were also determined, and it was found that the glutathione peroxidase activity of microalgae increased under certain seawater stress, indicating that glutathione peroxidase played an indispensable role in the removal of reactive oxygen species produced by seawater stress.

PeMPK7 is induced in an ROS-dependent manner and confers poplar para-hydroxybenzoic acid stress resistance through the removal of ROS

The continuous cropping of poplar plantations will accumulate allelochemicals such as para-hydroxybenzoic acid (pHBA) in the soil, which restricts the growth and biomass of poplar. Mitogen-activated protein kinase (MAPK) cascades are widely involved in environmental stress responses in plants. However, little is known about the role of MAPK cascade genes in the response to pHBA stress until now. Here, a novel group C MAPK gene, PeMPK7, from Populus × euramericana was characterized. The PeMPK7 transcript was induced by exogenous pHBA and H2O2, and its induced transcription by pHBA was blocked by the reactive oxygen species (ROS) manipulators. Overexpression of PeMPK7 in poplar alleviated the phenotypic injury induced by pHBA stress, reduced H2O2 accumulation and alleviated the oxidative injury in leaf cells. The expression of the encoding genes and enzyme activity of the antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) were upregulated in transgenic poplars under pHBA conditions, which will help to remove excessive ROS. In addition, the enhanced soluble sugar and free proline in transgenic poplar seedlings may contribute to maintaining osmotic homeostasis under pHBA stress. Furthermore, the interaction between PeMPKK3 and PeMPK7 was confirmed. A schematic model was proposed to show the regulatory mechanism of PeMPK7 in response to pHBA stress.

A biomimetic zeolite-based nanoenzyme contributes to neuroprotection in the neurovascular unit after ischaemic stroke via efficient removal of zinc and ROS

Zeolite-based nanomaterials have a large number of applications in the field of medicine due to their high porosity, biocompatibility and biological stability. In this study, we designed cerium (Ce)-doped Linde Type A (LTA) zeolite-based nanomaterials (Ce/Zeo-NMs) as a multifunctional mesoporous nanoenzyme to reduce dysfunction of the neurovascular unit (NVU) and attenuate cerebral ischaemia-reperfusion (I/R) injury. Owing to its unique adsorption capacity and mimetic catalytic activities, Ce@Zeo-NMs adsorbed excess zinc ions and exhibited scavenging activity against reactive oxygen species (ROS) induced by acute I/R, thus reshaping the oxidative and zinc microenvironment in the ischaemic brain. In vivo results demonstrated that Ce@Zeo-NMs significantly reduced ischaemic damage to the NVU by decreasing the infarct area, protecting against breakdown of the blood–brain barrier (BBB) via inhibiting the degradation of tight junction proteins (TJPs) and inhibiting activation of microglia and astrocytes in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). Taken together, these findings indicated that Ce@Zeo-NMs may serve as a promising dual-targeting therapeutic agent for alleviating cerebral I/R injury. Statement of SignificanceCerium (Ce)-doped Linde Type A zeolite-based nanomaterials (Ce/Zeo-NMs) as a multifunctional mesoporous nanoenzyme were designed for inducing neuroprotection after ischaemic stroke by reducing dysfunction of the neurovascular unit (NVU). Ce@Zeo-NMs had the ability to adsorb excessive Zn2+ and showed mimetic enzymatic activities. As a result, Ce@Zeo-NMs protected against cerebral ischaemia and reduced the damage of NVU by improving the integrity of blood brain barrier (BBB) and inhibiting activation of microglia and astrocytes in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). These findings indicated that Ce@Zeo-NMs may serve as a therapeutic strategy for neuroprotection and functional recovery upon ischaemic stroke onset.

Reactive Oxygen Species, Antioxidant Responses and Implications from a Microbial Modulation Perspective.

Simple SummaryEnvironmental conditions are subject to unprecedented changes due to recent progressive anthropogenic activities on our planet. Plants, as the frontline of food security, are susceptible to these changes, resulting in the generation of unavoidable byproducts of metabolism (ROS), which eventually affect their productivity. The response of plants to these unfavorable conditions is highly intricate and depends on several factors, among them are the species/genotype tolerance level, intensity, and duration of stress factors. Defensive mechanisms in plant systems, by nature, are concerned primarily with generating enzymatic and non-enzymatic antioxidants. In addition to this, plant-microbe interactions have been found to improve immune systems in plants suffering from drought and salinity stress.Plants are exposed to various environmental stresses in their lifespan that threaten their survival. Reactive oxygen species (ROS), the byproducts of aerobic metabolism, are essential signalling molecules in regulating multiple plant developmental processes as well as in reinforcing plant tolerance to biotic and abiotic stimuli. However, intensified environmental challenges such as salinity, drought, UV irradiation, and heavy metals usually interfere with natural ROS metabolism and homeostasis, thus aggravating ROS generation excessively and ultimately resulting in oxidative stress. Cellular damage is confined to the degradation of biomolecular structures, including carbohydrates, proteins, lipids, pigments, and DNA. The nature of the double-edged function of ROS as a secondary messenger or harmful oxidant has been attributed to the degree of existing balance between cellular ROS production and ROS removal machinery. The activities of enzyme-based antioxidants, catalase (CAT, EC 1.11.1.6), monodehydroascorbate reductase (MDHAR, E.C.1.6.5.4), dehydroascorbate reductase (DHAR, EC 1.8.5.1), superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), glutathione reductase (GR, EC 1.6.4.2), and guaiacol peroxidase (GPX, EC 1.11.1.7); and non-enzyme based antioxidant molecules, ascorbate (AA), glutathione (GSH), carotenoids, α-tocopherol, prolines, flavonoids, and phenolics, are indeed parts of the defensive strategies developed by plants to scavenge excess ROS and to maintain cellular redox homeostasis during oxidative stress. This review briefly summarises current knowledge on enzymatic and non-enzymatic antioxidant machinery in plants. Moreover, additional information about the beneficial impact of the microbiome on countering abiotic/biotic stresses in association with roots and plant tissues has also been provided.

中华蚊母树在干旱-水淹交叉胁迫下形态和活性氧代谢的适应机制

PDF HTML阅读 XML下载 导出引用 引用提醒 中华蚊母树在干旱-水淹交叉胁迫下形态和活性氧代谢的适应机制 DOI: 10.5846/stxb202008062050 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（51779127）；国家111引智基地项目（D20015）；中国科学院水生植物与流域生态重点实验室开放课题基金（E0520204）；三峡库区珍稀植物种子保存技术与设施研究科研项目-耐水淹种质资源调查及收集（SDHZ2021346） Adaptive mechanism of morphology and reactive oxygen species metabolism of Distylium chinense seedlings to alternate drought and submergence stresses Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为阐明中华蚊母树（Distylium chinense）在消落带干旱-水淹交叉胁迫下的形态和活性氧（ROS）代谢适应机制，通过控制实验模拟了三峡水库消落带的水文节律，研究了干旱-水淹交叉胁迫及恢复过程施加不同外源物质对中华蚊母树形态学和ROS清除的变化。结果表明：（1）前期干旱胁迫增强了中华蚊母树对后期水淹胁迫的适应，主要表现在叶片脱落、大量不定根的形成及茎基部膨大等形态学的变化；（2）干旱或水淹单一胁迫下，中华蚊母树·OH、O2·等ROS水平明显高于对照，表现出氧化应激反应，其超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）等抗氧化系统酶活性及脯氨酸（Pro）等抗氧化系统小分子含量也均显著高于对照，表现出一定的抗氧化防御作用机制，且在复合胁迫下，SOD、CAT、APX酶活性及Pro含量显著高于单一胁迫；（3）恢复阶段，相关性分析表明，中华蚊母树清除ROS （·OH、O2·）的酶促（SOD、CAT、APX）及非酶促（Pro）系统具有一定的协同性。同时，恢复阶段施加脱落酸（ABA），内源Pro显著高于正常水平；施加Pro，SOD、CAT等抗氧化酶活性显著高于对照；施加可溶性糖（Glu），APX活性显著升高。表明外源添加ABA、Pro、Glu，均对ROS的清除产生显著影响，同时，SOD活性显著高于CAT和APX活性，因此SOD可能是中华蚊母树清除冗余ROS的主要因子。因此，中华蚊母树形态学的变化、较高的脯氨酸积累和对ROS有效的清除防御，可能是其适应干旱-水淹交叉胁迫的主要机制，ABA、Pro、Glu等外源物质的添加对中华蚊母树的胁迫恢复过程具有显著的促进作用，前期干旱可提高中华蚊母树植株对后期水淹的耐受能力。 Abstract:Distylium chinense, the genus Distylium of the Hamamelidacea, is an evergreen perennial shrub between 0.8 and 1.2 m in height, native to the riparian areas and wetlands and a dominant species in the riparian areas of the Three Gorges Reservoir (TGR) region of the Yangtze River and its branches. Our previous studies showed that D. chinense had a certain survival rate in the middle and upper part of the water level fluctuation zone (WLFZ) of the TGR to alternate drought and submergence stresses, but the adaptive mechanisms of its morphology and reactive oxygen species (ROS) metabolism is still unknown. To evaluate its adaptation mechanisms of D. chinense to alternate drought and submergence stresses, a simulation alternate drought and submergence experiment was conducted, and morphology and ROS metabolism of D. chinense seedlings and their recovery growth with different exogenous substances, i.e., abscisic acid(ABA), proline(Pro) and glucose (Glu), were analyzed, including adventitious roots, plant height, base stem diameter, leaf numbers, ROS content, enzymatic and non-enzymatic antioxidant parameters. The results were as follows. (1) The early drought stress stimulated the adaptation of D. chinense seedlings to the later flooding stress.The adaptation mainly refered as more morphological changes of stems and roots i.e., stem base hypertrophy, formation and development of adventitious roots. (2) Comparing to the control group, there were significant increases in the ·OH and the O2· in D. chinense seedlings under either drought or flooding stress, which showed oxidative stress responses occurred and their superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) activities and the proline (Pro) contents were also significantly higher than those of controls, which showed that the enzymatic and non-enzymatic antioxidants were induced as a defense mechanism. Under the alternate drought and submergence stresses, the activities of SOD, APX and CAT and Pro contents were higher than those under single drought or flooding stress. (3) Correlation analysis showed that to a certain extent there were coordinated effects between the enzymatic (SOD, CAT, APX) and non-enzymatic (Pro) systems in ROS-scavenging in D. chinense. Exogenous ABA significantly triggered an increase of endogenous Pro contents compared to the controls during the recovery growth and the activity of SOD, CAT and APX was significantly higher than those of the control group under exogenous Pro treatment. Of these, the activities of SOD were significantly higher than those of CAT and APX. The activities of APX increased significantly when soluble sugar (Glu) was added. The ABA, Pro and Glu all had significant influences on the removal of ROS and the ability of D. chinense to up-regulate the SOD activity might be an important attribute for the removal of redundant ROS linked to drought and flooding tolerance. Thus the higher Pro accumulation and effective defense to ROS could be the main physiological adaptation mechanisms for D. chinense under the alternate drought and submergence stresses. The combination of morphological changes and the up-regulating of enzymatic and non-enzymatic anti-oxidative system might be the main mechanisms of D. chinense adapting to alternate drought and flooding stresses. The ABA, Pro and Glu treatment significantly promoted the recovery growth of D. chinense.. The drought in the early stage could improve the tolerance to submergence in the later stage. 参考文献 相似文献 引证文献

Property-activity relationship between physicochemical properties of PM2.5 and their activation of NLRP3 inflammasome

Air pollution is becoming severe environment factor affecting human health. More and more research has indicated that fine particulate matter (PM2.5) plays a critical role in causing pulmonary inflammation or fibrosis, which potentially is ascribed to the activation of nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome. However, the underlying property-activity relationship between the physicochemical properties of PM2.5 and their activation of NLRP3 inflammasome remains unclear. Herein, various ways, such as metal chelation, organic extraction, ROS consumption, charge neutralization and particle dispersion, were applied to interfere with the effects of metal ion, polycyclic aromatic hydrocarbons (PAHs), reactive oxygen species (ROS), charge and size. It was found that aggregated size and PAHs could activate the NLRP3 inflammasome through lysosome rupture and potassium efflux, respectively. Metal ion, PAHs and surface ROS could also activate the NLRP3 inflammasome through mitochondrial ROS production. However, neutralization of PM2.5 with the negative surface charge could not relieve the activation of NLRP3 inflammasome. Furthermore, oropharyngeal aspiration of various modified PM2.5 were adopted to explore their effects on lung fibrosis, which showed the consistent results with those in cellular levels. Removal of metal ion, PAHs and ROS as well as reduction of size of PM2.5 could reduce collagen deposition in the lung tissue of mice, while the charge neutralization of PM2.5 increased this collagen deposition. This study provides great insights to clarify the property-activity relationship of PM2.5.

Computational Modeling of Mitochondria to Understand the Dynamics of Oxidative Stress.

Mitochondria are complex organelles that use catabolic metabolism to produce ATP which is the critical energy source for cell function. Oxidative phosphorylation by the electron transport chain, which receives reducing equivalents (NADH and FADH2) from the tricarboxylic acid cycle, also produces reactive oxygen species (ROS) as a by-product at complex I and III. ROS play a significant role in health and disease. In order to better understand this process, a computational model of mitochondrial energy metabolism and the production of ROS has been developed. The model demonstrates the process regulating ROS production and removal and how different energy substrates can affect ROS production.

Triclosan Induced Oxidative Stress, Estrogenicity, Mutagenicity, Carcinogenicity, and Genotoxicity: A Novel Therapeutic Approach

Triclosan (TCS) is present in toothpaste and other cosmetic products as an antibacterial and anti-fungal agent. This manuscript highlights that TCS is a potential oxidative stress-causing agent, an estrogenic, mutagenic, cancer-causing agent, and genotoxic agent present in cosmetic products. This study also summarizes the therapeutic approach to overcome all of the harmful effects. It is a popular current topic, and a new research study is needed to find a new alternative as an antibacterial and anti-fungal agent instead of TCS. TCS causes oxidative stress when the dynamic balance in synthesizing and removing reactive oxygen species (ROS) within typical physiological circumstances is disturbed. The antioxidant defence system includes both enzymatic and non-enzymatic antioxidants produced by the organism to tackle the harmful effects of ROS. TCSs have estrogenic, proliferative, and apoptotic properties due to research on cell fate. The mutagenic potential of TCS has been examined using in vitro and in vivo research in prokaryotic, eukaryotic systems, and mammalian cells. It also induces carcinogenic, estrogenic, and mutagenic effects. TCS's therapeutic effects, especially against inflammatory skin conditions, have been demonstrated by many materials gathered from in vitro and in vivo experiments. The new findings suggest that TCS, a commonly used cosmetic product, may cause cancer, as shown by animal and human models and clinical trials. TCS is not effectively regulated, as evidenced by its presence in various environmental media, human bodies, and animals. Its irresponsible usage and disposal may endanger humans and wildlife. TCS has been found to damage a wide variety of cells in cell-based investigations. TCS's exact function in the environmental selection of antibiotic and multidrug resistance genes is still unclear. Comprehensive evaluations of these domains, especially to derive serious human health risk inferences from TCS outcomes, may help future research and legislation to better serve the public's health.