Components Of Antioxidant Defense System Research Articles

Exploiting the role of plant growth promoting rhizobacteria in reducing heavy metal toxicity of pepper (Capsicum annuum L.).

Microorganisms are cost-effective and eco-friendly alternative methods for removing heavy metals (HM) from contaminated agricultural soils. Therefore, this study aims to identify and characterize HM-tolerant (HMT) plant growth-promoting rhizobacteria (PGPR) isolated from industry-contaminated soils to determine their impact as bioremediators on HM-stressed pepper plants. Four isolates [Pseudomonas azotoformans (Pa), Serratia rubidaea (Sr), Paenibacillus pabuli (Pp) and Bacillus velezensis (Bv)] were identified based on their remarkable levels of HM tolerance in vitro. Field studies were conducted to evaluate the growth promotion and tolerance to HM toxicity of pepper plants grown in HM-polluted soils. Plants exposed to HM stress showed improved growth, physio-biochemistry, and antioxidant defense system components when treated with any of the individual isolates, in contrast to the control group that did not receive PGPR. The combined treatment of the tested HMT PGPR was, however, relatively superior to other treatments. Compared to no or single PGPR treatment, the consortia (Pa+Sr+Pp+Bv) increased the photosynthetic pigment contents, relative water content, and membrane stability index but lowered the electrolyte leakage and contents of malondialdehyde and hydrogen peroxide by suppressing the (non) enzymatic antioxidants in plant tissues. In pepper, Cd, Cu, Pb, and Ni contents decreased by 88.0-88.5, 63.8-66.5, 66.2-67.0, and 90.2-90.9% in leaves, and 87.2-88.1, 69.4-70.0%, 80.0-81.3, and 92.3%% in fruits, respectively. Thus, these PGPR are highly effective at immobilizing HM and reducing translocation in planta. These findings indicate that the application of HMT PGPR could be a promising "bioremediation" strategy to enhance growth and productivity of crops cultivated in soils contaminated with HM for sustainable agricultural practices.

Malondialdehyde, Antioxidant Defense System Components and Their Relationship with Anthropometric Measures and Lipid Metabolism Biomarkers in Apparently Healthy Women.

Cardiovascular diseases are the leading cause of mortality worldwide. Since atherosclerosis, an inflammatory, lipid-driven disease, is an underlying basis for the development of cardiovascular disease, it is important to understand its relationship with confounding factors, such as oxidative lipid degradation. In contrast, circulating antioxidants prevent oxidative lipid damage, and therefore, may be associated with reduced development of atherosclerosis. We aimed to assess oxidative lipid degradation biomarker malondialdehyde (MDA) and antioxidant defense system components, total antioxidant capacity (TAC) and superoxide dismutase (SOD) inhibition rate levels, in healthy women and evaluate their relationships with age, anthropometric measures, and lipid metabolism biomarkers. The study included 86 healthy middle-aged women. MDA in human serum samples was evaluated by HPLC, and the TAC and SOD inhibition rates were measured by photometric methods. MDA was found to be associated with age, total cholesterol, non-HDL cholesterol, apolipoprotein B and triacylglycerols. TAC was shown to be associated with age, BMI, and waist circumference, as well as lipid metabolism biomarkers apolipoprotein B and triacylglycerol, while SOD inhibition rate was only associated with total cholesterol, apolipoprotein B and triacylglycerols. In conclusion, the association of oxidative status indices, MDA, TAC and SOD, with cardiovascular risk factors suggests that they could be additional useful biomarkers in the research of aging, obesity, and atherosclerosis pathogenesis.

CONSERVATION AND VARIABILITY OF THE ANTIOXIDANT PROTECTION SYSTEM OF THE RETINAL PIGMENT EPITHELIA IN VERTEBRATES

In the course of evolution and adaptation to life conditions, organisms have developed the strategies that allow to use of the reactive oxygen species (ROS) in regulation of physiological processes and in maintenance of homeostasis. Retinal pigment epithelium (RPE) is one of the prime examples of tissues with a high level of metabolism and intracellular ROS, that have the more risk of damage after oxidative stress (OS), under the influence of exogenous or endogenous stress factors. Vertebrate RPE cells, despite the conservatism of the eye tissue structures and their main functions, respond differently to OS are due to the taхon-species specificity of the components of signaling pathways that form the antioxidant defense system (AODS). Transcription factors, in particular, Nrf2 play a key role in AODS. AODS in RPE includes the several levels of regulation, interaction of which ensures the stability of morphofunctional state of the cells. Phylogenetic analysis of the key components of AODS in various vertebrates revealed not only conservation, but also variability in the protein domain organization. This may reflect the differences in functions, adaptability and regenerative potential. The identification of AODS mechanisms that ensure the morphofunctional stability of RPE cells is of fundamental importance and is aimed at finding tissue-specific targets for effective treatment of a spectrum of eye diseases.

Foliar Application of Ascorbic Acid and Tocopherol in Conferring Salt Tolerance in Rapeseed by Enhancing K+/Na+ Homeostasis, Osmoregulation, Antioxidant Defense, and Glyoxalase System

This study explored the role of exogenous α-Toc (0.5 mM) and Asc (1 mM) in alleviating the damaging effects of salt stress in rapeseed plants (Brassica campestris cv. BARI Sarisha-17). Exposure of 21-day-old plants to different levels of salt stress (75 mM and 150 mM NaCl) resulted in the higher accumulation of sodium ions (Na+), reduced potassium ion (K+) levels, lower K+/Na+ ratio, increased oxidative damage, chlorophyll (Chl) breakdown, and disrupted antioxidant and glyoxalase systems. Phenotype responses to salt stress included reductions in plant height, shoot fresh weight, dry weight, number of siliques plant−1, silique length, number of seeds silique−1, 1000-seed weight, and seed yield plant−1. Exogenous α-Toc and Asc applications enhanced the levels of endogenous ascorbate, glutathione (GSH), AsA/dehydroascorbate ratios, GSH/glutathione disulfide, ascorbate peroxidase, monodehydroascorbate reductase, glutathione reductase, glutathione peroxidase, and catalase activities in the salt-stressed plants. Exogenous α-Toc and Asc enhanced antioxidant defense system components and insured better oxidative stress tolerance, as indicated by reduced hydrogen peroxide generation, membrane lipid peroxidation, and electrolyte leakage. Exogenous α-Toc and Asc increased glyoxalase I and glyoxalase II activities in the salt-affected plants. Moreover, they regulated proline levels and increased the leaf relative water content, as well as the Chl level. Exogenous α-Toc and Asc also restored growth and improved yield attributes and seed yield per plants in the salt-affected rapeseed.

Trypanosoma cruzi iron superoxide dismutases: insights from phylogenetics to chemotherapeutic target assessment

BackgroundComponents of the antioxidant defense system in Trypanosoma cruzi are potential targets for new drug development. Superoxide dismutases (SODs) constitute key components of antioxidant defense systems, removing excess superoxide anions by converting them into oxygen and hydrogen peroxide. The main goal of the present study was to investigate the genes coding for iron superoxide dismutase (FeSOD) in T. cruzi strains from an evolutionary perspective.MethodsIn this study, molecular biology methods and phylogenetic studies were combined with drug assays. The FeSOD-A and FeSOD-B genes of 35 T. cruzi strains, belonging to six discrete typing units (Tcl–TcVI), from different hosts and geographical regions were amplified by PCR and sequenced using the Sanger method. Evolutionary trees were reconstructed based on Bayesian inference and maximum likelihood methods. Drugs that potentially interacted with T. cruzi FeSODs were identified and tested against the parasites.ResultsOur results suggest that T. cruzi FeSOD types are members of distinct families. Gene copies of FeSOD-A (n = 2), FeSOD-B (n = 4) and FeSOD-C (n = 4) were identified in the genome of the T. cruzi reference clone CL Brener. Phylogenetic inference supported the presence of two functional variants of each FeSOD type across the T. cruzi strains. Phylogenetic trees revealed a monophyletic group of FeSOD genes of T. cruzi TcIV strains in both distinct genes. Altogether, our results support the hypothesis that gene duplication followed by divergence shaped the evolution of T. cruzi FeSODs. Two drugs, mangafodipir and polaprezinc, that potentially interact with T. cruzi FeSODs were identified and tested in vitro against amastigotes and trypomastigotes: mangafodipir had a low trypanocidal effect and polaprezinc was inactive.ConclusionsOur study contributes to a better understanding of the molecular biodiversity of T. cruzi FeSODs. Herein we provide a successful approach to the study of gene/protein families as potential drug targets.Graphical

Oxidative stress in obesity and insulin resistance

Since obesity is one of the main factors in the development of insulin resistance (IR) and is also associated with increased oxidative stress (OxS) rate, this study aims to review the published literature to collate and provide a comprehensive summary of the studies related to the status of the OxS in the pathogenesis of obesity and related IR. OxS represents an imbalance between the production of reactive oxygen and nitrogen species (RONS) and the capacity of the antioxidant defense system (AOS) to neutralize RONS. A steady-state of RONS level is maintained through endogenous enzymatic and non-enzymatic AOS components. Three crucial enzymes, which suppress the formation of free radicals, are superoxide dismutases, catalases, and glutathione peroxidases. The second line of AOS includes non-enzymatic components such as vitamins C and E, coenzyme Q, and glutathione which neutralizes free radicals by donating electrons to RONS. Emerging evidence suggests that high RONS levels contribute to the progression of OxS in obesity by activating inflammatory pathways and thus leading to the development of pathological states, including IR. In addition, decreased level of AOS components in obesity increases the susceptibility to oxidative tissue damage and further progression of its comorbidities. Increased OxS in accumulated adipose tissue should be an imperative target for developing new therapies in obesity-related IR.

Enhancing Salt Tolerance in Soybean by Exogenous Boron: Intrinsic Study of the Ascorbate-Glutathione and Glyoxalase Pathways.

Boron (B) performs physiological functions in higher plants as an essential micronutrient, but its protective role in salt stress is poorly understood. Soybean (Glycine max L.) is planted widely throughout the world, and salinity has adverse effects on its physiology. Here, the role of B (1 mM boric acid) in salt stress was studied by subjecting soybean plants to two levels of salt stress: mild (75 mM NaCl) and severe (150 mM NaCl). Exogenous B relieved oxidative stress by enhancing antioxidant defense system components, such as ascorbate (AsA) levels, AsA/dehydroascorbate ratios, glutathione (GSH) levels, the GSH and glutathione disulfide ratios, and ascorbate peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase activities. B also enhanced the methylglyoxal detoxification process by upregulation of the components of the glyoxalase system in salt-stressed plants. Overall, B supplementation enhanced antioxidant defense and glyoxalase system components to alleviate oxidative stress and MG toxicity induced by salt stress. B also improved the physiology of salt-affected soybean plants.

Oral Nigella sativa oil administration alleviates arsenic-induced redox imbalance, DNA damage, and metabolic and histological alterations in rat liver.

Arsenic, an omnipresent environmental contaminant, is regarded as a potent hepatotoxin. Nigella sativa oil (NSO) consumption has been shown to improve hepatic functions in various in vivo models of acute hepatic injury. The present study evaluates the protective efficacy of NSO against sodium arsenate (As)-induced deleterious alterations in the liver. Male Wistar rats were divided into four groups, namely, control, As, NSO, and AsNSO. After pre-treating rats in AsNSO and NSO groups with NSO (2 mL/kg bwt, orally) for 14 days, NSO treatment was further extended for 30 days, with and without As treatment (5 mg/kg bwt, orally), respectively. As induced an upsurge in serum ALT and AST activities indicating liver injury, as also confirmed by the histopathological findings. As caused significant alterations in the activities of membrane marker enzymes and carbohydrate metabolic enzymes, and in the vital components of antioxidant defense system. Marked DNA damage and hepatic arsenic accumulation were also observed in As-treated rats. Oral NSO administration ameliorated these deleterious alterations and improved overall hepatic antioxidant and metabolic status in As-treated rats. Prevention of oxidative damage could be the underlying mechanism of NSO-mediated protective effects. The results suggest that NSO could be a useful dietary supplement in the management of arsenic hepatotoxicity.

Seed priming with ascorbic acid enhances salt tolerance in micro-tom tomato plants by modifying the antioxidant defense system components

Although ascorbic acid (AsA) has been known to improve plant defense system components against salt stressful-conditions, little is known about physiological and biochemical responses of AsA-mediated alleviation of salt stress in tomatoes. The main objective of this work was, therefore, to explore the role of ascorbic acid application via seed priming on antioxidant defense responses and growth and fruit yield regulation in tomato Micro-Tom under salt stress. The experiment was carried out using a 2 × 2 factorial completely randomized design with four replicates. In this way, seed priming with AsA (0 and 100 mM AsA) was used in Micro-Tom seeds to improve the tolerance of subsequent salt-stress exposure (0 and 100 mM NaCl). The AsA priming effect was assessed on subsequent exposure to salt stress conditions with a physiological and biochemical approaches, involving antioxidant responses. Overall results indicated that AsA plays a role in alleviating the negative effects of salt stress by increasing water potential and water use efficiency, reducing Na + content, lipid peroxidation and H 2 O 2 content, and increasing total pigments content, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POX), glutathione peroxidase (GPX) and glutathione reductase (GR) activities and GSH content, leading to better plant growth and higher yields. Thus, our results indicated that priming with AsA is an efficient management technique that can be used to alleviate the deleterious effects of salt stress and enhance the salt tolerance of Micro-Tom plants by modulation of antioxidant mechanisms. • Priming with AsA is a management technique to alleviate deleterious effects of salt-stressful. • Conditions. • Seed priming with AsA enhances salt tolerance in Micro-tom tomato plants by modifying the antioxidant defense system. • Salt tolerance conferred by seed priming can be associated with the modulation of ROS scavenging enzymes.

Low selenium serum levels are associated with poor clinical outcomes in critically ill children

Rationale: Major gastrointestinal surgeries in childhood era may lead to Pediatric Intensive Care Unit (PICU) admission due to the oxidative stress and inflammation following surgeries, acute stress response that may be associated with poor clinical outcomes. Previous studies reported selenium as a key component of antioxidant defense system which serum selenium levels are directly correlated with the severity of oxidative stress. In this study, we investigated the possible relation between serum selenium concentrations and clinical outcomes following major gastrointestinal surgeries.

Brassinosteroids Regulate Functional Components of Antioxidative Defense System in Salt Stressed Maize Seedlings

The purpose of current investigation was to explore the role of brassinosteroids (BRs) in Zea mays L. var. DKC 9106 seedlings subjected to salt stress. The seedlings were raised under controlled laboratory conditions and subjected to different concentrations of NaCl (0, 40, 60, 80, 100 mM) for 10 days. The impact of pre-sowing treatment of both 28-homobrassionolide (HBL) and 24-epibrassinolide (EBL) on defense system of Z. mays L. under salt stress was studied by analyzing Na+ and K+ ions, malondialdehyde content (MDA), antioxidative enzymes activities (peroxidase, POD; catalase, CAT; dehydroascorbate reductase, DHAR; monodehydroascorbate reductase, MDHAR), osmoprotectants (proline, glycine betaine, mannitol, and total osmolytes content), total phenolic content, total flavonoid content, and 1,1-diphenylpicrylhydrazyl (DPPH) free radical scavenging activity. The results of our finding showed that treatment of both HBL and EBL under high salt stress balanced the ionic status by decreasing the Na+ ions content by 21.23% and 38.94%, respectively, and enhancing the K+ ions content by 51.94% and 26.66%, respectively. Treatment of both BRs also overcome the oxidative damage induced due to salinity stress by reducing the MDA accumulation 19.50% and 45.0%, respectively, and enhancing the activities of antioxidative enzymes. The osmoprotectants: proline (50.08% and 17.03%), glycine betaine (35.57% and 28.16%), and mannitol content (2.80% and 20.98%) were markedly increased by the treatment of both HBL and EBL, respectively. Further, treatment of both HBL and EBL also increased the total phenolic content by 11.68% and 5.80%, total flavonoid content by 31.56 and 31.09% and DPPH free radical scavenging activity by 37.99% and 77.41%, respectively. Overall the treatment of BRs before seed sowing considerably conquer the salinity-induced damage by stimulating functional components of antioxidative defense system and ultimately reduced oxidative damage.

Exogenous vanillic acid enhances salt tolerance of tomato: Insight into plant antioxidant defense and glyoxalase systems

We investigated vanillic acid-induced salt tolerance in tomato by exploring the plant defense systems. Ten-d-old tomato (Solanum lycopersicum L. cv. Pusa Ruby) seedlings were treated with salt (NaCl; 150 mM) and vanillic acid (VA; 40 and 50 μM) separately and in combination with salt. Salinity restricted seedlings growth, biomass accumulation, chlorophyll and carotenoid contents. Salt-induced osmotic stress was indicated by lower leaf relative water content (RWC) and elevated proline (Pro) content, where higher Na+/K+ ratio indicated the ionic toxicity. Tomato seedlings went through oxidative damage due to acute reactive oxygen species (ROS) production and lipoxygenase (LOX) activity and confirmed by higher lipid peroxidation and membrane damage under salinity. Conversely, exogenous VA reduced osmotic and ionic toxicity in stressed-seedlings by enhancing the RWC and Pro level, and lowering Na+/K+ ratio, respectively. Exogenous VA up-regulated the components of antioxidant defense system in salt-treated seedlings resulted in the reduction of ROS production, LOX activity and membrane damage in stressed-seedlings. Additionally, VA application caused the reduction of toxic methylglyoxal accumulation under salt stress through the enhancement of glyoxalase system. Thus, VA-induced alleviation of osmotic, ionic and oxidative stresses leading to improve plant growth and chlorophyll synthesis in stressed-seedlings. So, VA significantly improves salinity tolerance and plant growth performance by involving the actions of plant antioxidant defense and glyoxalase systems.

Elevating tolerance of drought stress in Ocimum basilicum using pollen grains extract; a natural biostimulant by regulation of plant performance and antioxidant defense system

Drought is a major abiotic stress that limits performance of sweet basil (Ocimum basilicum L.), which is an important aromatic plant for flavor foods and traditional medicines. The influence of palm pollen grains extract (PGE) on growth, physio-biochemical attributes, water use efficiency (WUE), anatomical characteristics and antioxidant defense system components in basil plants was investigated under normal and water deficit stress conditions. The PGE was exogenously applied as a foliar spray at a rate of 1.0 g L‒1 to plants under full (70% of soil water-holding capacity; SWHC) or deficit irrigation (DI; 50% of SWHC) in a pot experiment repeated three times. Exposing basil plants to drought stress significantly disorganized their performance including oil yield and anatomical features, but increased their antioxidant defense system components. However, the application of PGE to DI-stressed plants significantly improved growth characteristics and the contents of essential oil, leaf photosynthetic pigments, soluble sugars, free proline, and ascorbic acid. Antioxidant enzyme activities, relative water content (RWC), WUE, and anatomical characteristics were also improved, while electrolyte leakage was significantly diminished compared to the corresponding control. Therefore, results obtained in this study recommend using PGE at 1.0 g L‒1 as a foliar application strategy for Ocimum basilicum plants grown under DI stress to maintain higher RWC and WUE, and lower EL, and improve plant growth and essential oil productivity by limiting the inhibitory effects of DI.

Экспериментальная модель криодеструкции кожи

We suggest the in vivo experimental model of skin cryodestruction, suitable for studying the processes, occurring after skin neoplasm cryosurgery. To develop the model we have used low-temperature exposure using a cryoprobe, providing the temperature below the tissue cryoresistance threshold in the area of contact between the applicator working surface and skin. The initiation of destructive and inflammatory processes, both local and systemic, was observed in this model. Local morphological manifestations corresponded to the first phase of wound–healing process. We noted the destructive and inflammatory signs accompanied by primary necrosis (due to direct thermal damage), and a leukocyte bank and secondary necrosis (resulting from hemodynamic disorders). The reparative processes in injured tissues were manifested in developed granulation tissue. At a system level, the tissue cryodestruction was accompanied by the oxidative stress development (an increased content of lipid peroxidation products, a suppressed enzymatic component of antioxidant defense system) and an increased content of cerulloplasmin and C-reactive protein in blood serum. Probl Cryobiol Cryomed 2019; 29(1): 088–101

The role of melatonin as a component of the antioxidant defense system in perimenopausal women with insomnia

To determine the ethnic features of the functioning of the 'lipid peroxidation-antioxidants' system and to evaluate the role of melatonin as one of the antioxidant defense system components in Caucasian and Asian perimenopausal women with insomnia. One hundred and ten perimenopausal women divided into Caucasian (Russian ethnic group (n=60)) and Asian (Buryat ethnic group (n=50)) were studied. All women underwent clinical-anamnestic examination. Diagnoses of insomnia and obstructive sleep apnea syndrome (OSAS) were made according to the results of specialized somnological questionnaires and polysomnographic monitoring. A multidimensional discriminant analysis was used to reveal the most informative parameters among the hormonal and metabolic parameters studied (melatonin 06.00-07.00h; 12.00-13.00h; 18.00-19.00h; 23.00-00.00h; lipid profile, lipid peroxidation and antioxidant defense system). The most informative indicators of the metabolic system in Caucasians with insomnia are morning, evening, night melatonin, ketodienes and conjugated trienes, oxidized glutathione (GSSG); with insomnia and OSAS: morning, day, night melatonin, substrates with conjugated double bonds, total cholesterol; in Asian women with insomnia: evening, night melatonin, superoxide dismutase activity (SOD), diene conjugates, active products of thiobarbituric acid, cholesterol of very low density lipoproteins; in women with insomnia and OSAS: morning, day melatonin, SOD, GSSG. The recalculation of the informativeness of each attribute as a percentage showed the prevalence of the influence of the antioxidant protection system parameters over those of lipid peroxidation processes. The contribution of melatonin to the total share of the antioxidant protection system components is more than 60%. Both in Caucasian and Asian women with sleep disorders, there is stress in the antioxidant defense system, where melatonin is the largest contributor.

Functional analysis of thioredoxin from the desert lichen-forming fungus, Endocarpon pusillum Hedwig, reveals its role in stress tolerance.

Endocarpon pusillum is a lichen-forming fungus with an outstanding stress resistance property closely related to its antioxidant system. In this study, thioredoxin (Trx), one of the main components of antioxidant defense systems in E. pusillum (EpTrx), was characterized and analyzed both in transgenic yeasts and in vitro. Our analyses identified that the heterologous expression of EpTrx in the yeast Pichia pastoris significantly enhanced its resistance to osmotic and oxidative stresses. Assays in vitro showed EpTrx acted as a disulfide reductase as well as a molecular chaperone by assembling into various polymeric structures. Upon exposure to heat-shock stress, EpTrx exhibited weaker disulfide reductase activity but stronger chaperone activity, which coincided with the switching of the protein complexes from low molecular weight forms to high molecular weight complexes. Specifically, we found that Cys31 near but not at the active site was crucial in promoting the structural and functional transitions, most likely by accelerating the formation of intermolecular disulfide bond. Transgenic Saccharomyces cerevisiae harboring the native EpTrx exhibited stronger tolerance to oxidative, osmotic and high temperature stresses than the corresponding yeast strain containing the mutant EpTrx (C31S). Our results provide the first molecular evidence on how Trx influences stress response in lichen-forming fungi.

Piriformospora indica: Potential and Significance in Plant Stress Tolerance.

Owing to its exceptional ability to efficiently promote plant growth, protection and stress tolerance, a mycorrhiza like endophytic Agaricomycetes fungus Piriformospora indica has received a great attention over the last few decades. P. indica is an axenically cultiviable fungus which exhibits its versatility for colonizing/hosting a broad range of plant species through directly manipulating plant hormone-signaling pathway during the course of mutualism. P. indica-root colonization leads to a better plant performance in all respect, including enhanced root proliferation by indole-3-acetic acid production which in turn results into better nutrient-acquisition and subsequently to improved crop growth and productivity. Additionally, P. indica can induce both local and systemic resistance to fungal and viral plant diseases through signal transduction. P. indica-mediated stimulation in antioxidant defense system components and expressing stress-related genes can confer crop/plant stress tolerance. Therefore, P. indica can biotize micropropagated plantlets and also help these plants to overcome transplantation shock. Nevertheless, it can also be involved in a more complex symbiotic relationship, such as tripartite symbiosis and can enhance population dynamic of plant growth promoting rhizobacteria. In brief, P. indica can be utilized as a plant promoter, bio-fertilizer, bioprotector, bioregulator, and biotization agent. The outcome of the recent literature appraised herein will help us to understand the physiological and molecular bases of mechanisms underlying P. indica-crop plant mutual relationship. Together, the discussion will be functional to comprehend the usefulness of crop plant-P. indica association in both achieving new insights into crop protection/improvement as well as in sustainable agriculture production.

Systematic characterization of the peroxidase gene family provides new insights into fungal pathogenicity in Magnaporthe oryzae.

Fungal pathogens have evolved antioxidant defense against reactive oxygen species produced as a part of host innate immunity. Recent studies proposed peroxidases as components of antioxidant defense system. However, the role of fungal peroxidases during interaction with host plants has not been explored at the genomic level. Here, we systematically identified peroxidase genes and analyzed their impact on fungal pathogenesis in a model plant pathogenic fungus, Magnaporthe oryzae. Phylogeny reconstruction placed 27 putative peroxidase genes into 15 clades. Expression profiles showed that majority of them are responsive to in planta condition and in vitro H2O2. Our analysis of individual deletion mutants for seven selected genes including MoPRX1 revealed that these genes contribute to fungal development and/or pathogenesis. We identified significant and positive correlations among sensitivity to H2O2, peroxidase activity and fungal pathogenicity. In-depth analysis of MoPRX1 demonstrated that it is a functional ortholog of thioredoxin peroxidase in Saccharomyces cerevisiae and is required for detoxification of the oxidative burst within host cells. Transcriptional profiling of other peroxidases in ΔMoprx1 suggested interwoven nature of the peroxidase-mediated antioxidant defense system. The results from this study provide insight into the infection strategy built on evolutionarily conserved peroxidases in the rice blast fungus.

PARAMETERS OF FREE-RADICAL OXIDATION AND ANTIOXIDANT DEFENCE SYSTEM IN RATS OF BOTH SEXES WITH SODIUM NITRITE INTOXICATION

<p>Long-term influence of sodium nitrite on rats causes an increase in lipid peroxidation products in blood and myocardial tissue in animals of both sexes and is accompanied by a decrease in activity of enzymic and non-enzymic components of antioxidant defence system. Under the conditions of intoxication, the process of LPO is less aggressive in females in the comparison with males.</p>

Brassinosteroids make plant life easier under abiotic stresses mainly by modulating major components of antioxidant defense system

Various abiotic stress factors significantly contribute to major worldwide-losses in crop productivity by mainly impacting plant’s stress tolerance/adaptive capacity. The latter is largely governed by the efficiency of antioxidant defense system for the metabolism of elevated reactive oxygen species (ROS), caused by different abiotic stresses. Plant antioxidant defense system includes both enzymatic (such as superoxide dismutase, SOD, E.C. 1.15.1.1; catalase, CAT, E.C. 1.11.1.6; glutathione reductase, GR, E.C. 1.6.4.2; peroxidase, POD, E.C. 1.11.1.7; ascorbate peroxidase, APX, E.C. 1.11.1.11; guaiacol peroxidase, GPX, E.C. 1.11.1.7) and non-enzymatic (such as ascorbic acid, AsA; glutathione, GSH; tocopherols; phenolics, proline etc.) components. Research reports on the status of various abiotic stresses and their impact on plant growth, development and productivity are extensive. However, least information is available on sustainable strategies for the mitigation of abiotic stress-mediated major consequences in plants. Brassinosteroids (BRs) are a novel group of phytohormones with significant growth promoting nature. BRs are considered as growth regulators with pleiotropic effects, as they influence diverse physiological processes like growth, germination of seeds, rhizogenesis, senescence etc. and also confer abiotic stress resistance in plants. In the light of recent reports this paper: (a) overviews major abiotic stresses and plant antioxidant defense system, (b) introduces BRs and highlights their significance in general plant growth and development, and (c) appraises recent literature available on BRs mediated modulation of various components of antioxidant defense system in plants under major abiotic stresses including metals/metalloids, drought, salinity, and temperature regimes. The outcome can be significant in devising future research in the current direction.