Antioxidant Enzyme System Research Articles

Leaf proteomic profiles in cacao scion-rootstock combinations tolerant and intolerant to cadmium toxicity

Cd contamination in cacao beans is one of the major problems faced by cocoa producing countries in Latin America. Cacao scion-rootstock combinations influence the Cd accumulation in the shoot of the plant. The objective of this work was to carry out a comparative analysis between cacao scion rootstock combinations (CCN 51/BN 34, CCN 51/PS 13.19, CCN 51/PH 16 and CCN 51/CCN 51), contrasting for tolerance to cadmium (Cd) toxicity, by means of leaf proteomic profiles, in order to elucidate molecular mechanisms involved in tolerance to Cd toxicity. Cacao scion-rootstock combinations were grown in soil with 150 mg Cd kg−1 soil, together with the control treatment. Leaf samples were collected 96 h after treatments were applied. There were alterations in the leaf proteome of the cacao scion-rootstock combinations, whose molecular responses to Cd toxicity varied depending on the combination. Leaf proteomic analyzes provided important information regarding the molecular mechanisms involved in the tolerance and intolerance of cacao scion-rootstock combinations to Cd toxicity. Enzymatic and non-enzymatic antioxidant systems, efficient for eliminating ROS, especially the expressions of APX and SOD, in addition to the increase in the abundance of metalloproteins, such as ferredoxins, rubredoxin, ALMT, Trx-1 and ABC-transporter were key mechanisms used in the Cd detoxification in cacao scion-rootstock combinations tolerant to Cd toxicity. Carboxylic acid metabolism, glucose activation and signal transduction were also important processes in the responses of cacao scion-rootstock combinations to Cd toxicity. The results confirmed CCN 51/BN 34 as a cacao scion-rootstock combination efficient in tolerance to Cd toxicity.

Comparative effects of silicon and silicon nanoparticles on the antioxidant system and cadmium uptake in tomato under cadmium stress

Cadmium (Cd) pollution is an important threat to agricultural production globally. Silicon (Si) and silicon nanoparticles (Si NPs) can mitigate Cd stress in plants. However, the mechanisms underlying the impacts of Si and Si NPs on Cd resistance, particularly in low-Si accumulators, remain inadequately understood. Accordingly, we conducted a comparative investigation into the roles of Si and Si NPs in regulating the antioxidant system (enzymes and antioxidants) and Cd uptake (influx rate, symplastic and apoplastic pathways) in tomato (a typical low-Si accumulator). The results revealed that Si and Si NPs improved tomato growth under Cd stress, and principal component analysis (PCA) demonstrated that Si NPs were more effective than Si. For oxidative damage, redundancy analysis (RDA) results showed that Si NPs ameliorated oxidative damage in both shoots and roots, whereas Si predominantly alleviated oxidative damage in roots. Simultaneously, Si and Si NPs regulated antioxidant enzymes and nonenzymatic antioxidants with distinct targets and strengths. Furthermore, Si and Si NPs decreased Cd concentration in tomato shoot, root, and xylem sap, while Si NPs induced a more significant decline in shoot and xylem sap Cd. Noninvasive microtest and quantitative estimation of trisodium-8-hydroxy-1,3,6-pyrenetrisulfonic (PTS, an apoplastic tracer) showed that Si and Si NPs reduced the Cd influx rate and apoplastic Cd uptake, while Si NPs induced a more significant reduction. Moreover, Si regulated the expression of genes responsible for Cd uptake (NRAMP2 and LCT1) and compartmentalization (HMA3), while Si NPs reduced the expression of NRAMP2. In conjunction with RDA, the results showed that Si and Si NPs decreased Cd uptake mainly by regulating the symplastic and apoplastic pathways, respectively. Overall, our results indicate that Si NPs is more effective in promoting tomato growth and alleviating oxidative damage than Si in tomato under Cd stress by modulating the antioxidant system and reducing apoplastic Cd uptake.

Alteration of the aortic vascular reactivity associated to excessive consumption of Hibiscus sabdariffa Linnaeus: Preliminary findings

The moderate production of reactive oxidative species (ROS) is important because ROS act as second messengers. However, their depletion through the over-activity of the antioxidant system may lead to reductive stress (RS) which is characterized by an increase in reducing equivalents and an elevation of some components of the antioxidant system disturbing redox homeostasis. Hibiscus sabdariffa Linnaeus (HSL) is a plant with antioxidant properties that provides compounds that favor the antioxidant system. However, excess chronic consumption could lead to the over expression of the antioxidant enzymatic system, and this could contribute to decrease ROS. Therefore, the objective of this study was to evaluate the alteration of the vascular reactivity associated to excessive and chronic consumption of HSL infusions at different percentages. 40 male Wistar rats were divided into 4 groups. Group 1 control (drinking tap water), group 2, 3 and 4, drinking water supplemented with 15, 30 and 60 g/L of HSL calyxes respectively. The systolic blood pressure (SBP), vascular reactivity, morphological changes, and different components of the enzymatic antioxidant system were evaluated in the thoracic aorta by spectrophotometry. We also determined glucose-6-phosphate dehydrogenase (G6PD), glutathione-S-transferase (GST), thioredoxin-reductase (TrxR), glutathione peroxidase (GPx) and glutathione reductase (GR) and some markers of the non-enzimatic system such as the NO3−/NO2−ratio, glutathione (GSH), selenium, thiols, lipoperoxidation (LPO), and 3-nitrityrosine (3-NT). Vasoconstriction was increased and vasorelaxation was decreased. These alterations were reversed by O2− and H2O2. There was an increase in the wall thickness and elastic fibers (p = 0.004 and p = 0.02, respectively) and in G6PD, GPX, TrxR (p = 0.02, p = 0.03, and p = 0.01 respectively). LPO, GSH (p = 0.01), and selenium (p = 0.04) were decreased. There was a decrease in thiols (p < 0.001), 3-NT (p = 0.04) and GST (p = 0.0005) in rats that received the infusion at 3 and 6%. The excess antioxidants provided by the HSL infusions at 3% and 6% modified vascular reactivity, increasing the enzymatic antioxidant system, and depleting ROS.

Physiological responses of typical subtropical landscape shrubs to artificial light at night.

Artificial light at night is rapidly spreading and has become an important component of global change. Although numerous studies have focused on its potential ecological impacts, the physiological response mechanisms of landscape plants to artificial light at night have rarely been quantified. With common landscape shrubs in subtropical regions of China, Hydrangea paniculata, Photinia fraseri and Ligustrum japonicum, as test materials, we exa-mined the responses of antioxidant enzyme system and biomass in the light environment at night under different light quality (yellow light, white light) with different light intensities (20, 40, 60 lx) . The results showed that artificial light at night significantly increased the membrane peroxidation, stimulated plant antioxidant protection systems and raised the antioxidant enzyme activities of the three species. The effects of light quality on plant antioxidant enzymes varied across dspecies. The peroxidase (POD) and catalase (CAT) activities of H. paniculata under white light were 1.5 and 1.3 times as that under yellow light, respectively. Both enzyme activities of P. fraseri were 1.1 times as that under white light than under yellow light. The activities of two enzymes in L. japonicum under white light were 88.6% and 99.5% of those under yellow light, respectively. The antioxidant enzyme activities of the three species increased with increasing light intensity at night, whereas the contents of malondialdehyde increased rapidly and the antioxidant enzyme activities decreased when beyond a certain light intensity threshold (at 120 d, the threshold was about 40 lx). The protective enzymes that played the major role under nighttime light stress were different among the three species. For H. paniculata, POD and CAT complemented each other to resist stress-induced oxidative damage, while the main enzyme of L. japonicum was POD. The biomass of the three species increased significantly under artificial light at night. H. paniculata was the most sensitive to nighttime light stress, while L. japonicum had the strongest resistance to the stress. The deciduous shrub H. paniculata could tolerate the white night light lower than 40 lx, while the evergreen shrubs P. fraseri and L. japonicum could tolerate the yellow night light lower than 40 lx.

Comprehensive Response of Rhodosporidium kratochvilovae to Glucose Starvation: A Transcriptomics-Based Analysis.

Microorganisms adopt diverse mechanisms to adapt to fluctuations of nutrients. Glucose is the preferred carbon and energy source for yeast. Yeast cells have developed many strategies to protect themselves from the negative impact of glucose starvation. Studies have indicated a significant increase of carotenoids in red yeast under glucose starvation. However, their regulatory mechanism is still unclear. In this study, we investigated the regulatory mechanism of carotenoid biosynthesis in Rhodosporidium kratochvilovae YM25235 under glucose starvation. More intracellular reactive oxygen species (ROS) was produced when glucose was exhausted. Enzymatic and non-enzymatic (mainly carotenoids) antioxidant systems in YM25235 were induced to protect cells from ROS-related damage. Transcriptome analysis revealed massive gene expression rearrangement in YM25235 under glucose starvation, leading to alterations in alternative carbon metabolic pathways. Some potential pathways for acetyl-CoA and then carotenoid biosynthesis, including fatty acid β-oxidation, amino acid metabolism, and pyruvate metabolism, were significantly enriched in KEGG analysis. Overexpression of the fatty acyl-CoA oxidase gene (RkACOX2), the first key rate-limiting enzyme of peroxisomal fatty acid β-oxidation, demonstrated that fatty acid β-oxidation could increase the acetyl-CoA and carotenoid concentration in YM25235. These findings contribute to a better understanding of the overall response of red yeast to glucose starvation and the regulatory mechanisms governing carotenoid biosynthesis under glucose starvation.

Antioxidant Effects of Quercetin Nanocrystals in Nanosuspension against Hydrogen Peroxide-Induced Oxidative Stress in a Zebrafish Model.

Quercetin, a flavonoid compound rich in hydroxyl groups, possesses antioxidant properties, whereas its poor water solubility limits its bioavailability. In pursuit of addressing the water solubility of quercetin and comprehending the impact of nanocrystal particle size on antioxidant efficacy, we prepared three different-sized quercetin nanocrystals, namely small (50 nm), medium (140 nm), and large (360 nm), using a nanosuspension method in this study. Within the in vitro setting, assessments employing solubility and radical scavenging assays revealed that quercetin nanocrystals displayed superior solubility (26, 21, and 13 fold corresponding to small, medium, and large particle sizes) and antioxidant performance compared to the coarse quercetin. Furthermore, quercetin nanocrystals of three particle sizes all demonstrated significant protection effects on the survival rate of H2O2-treated zebrafish at 72 h (77.78%, 73.33%, and 66.67% for small, medium, and large particle sizes, respectively), while the coarse quercetin group exhibited a low survival rate (53.3%) similar to the H2O2-treated group (47.8%). Moreover, all quercetin nanocrystals exhibited potent antioxidant capacity on both the antioxidants and enzymatic antioxidant system in H2O2-treated zebrafish to restore zebrafish to a normal state under oxidative stress. For instance, the levels of reactive oxygen species were reduced to 101.10%, 108.83%, and 109.77% of the normal levels for small, medium, and large particle-sized quercetin nanocrystals, respectively. In conclusion, quercetin nanocrystals demonstrated enhanced solubility, robust antioxidant capacity, and protective effects in zebrafish compared to coarse quercetin.

A neutral heteropolysaccharide from Halenia elliptica D. Don: Extraction, structural characterization, antioxidant and antiaging activities

Halenia elliptica D. Don (H. elliptica), which is also known as “heijicao” and “luanehuamao” in China, is recognised as a valuable Tibetan medicinal plant with polysaccharides as the main active ingredient. However, studies on the polysaccharides isolated from H. elliptica are few. A polysaccharide (HEPN-1) with a molecular weight of 10.80 kDa was mainly composed of Gal, Ara, Man, Glc, Rha and Fuc in a molar ratio of 25.56:24.52:4.58:3.37:2.62:1.00. Structural analysis showed that HEPN-1 had a backbone mainly consisting of 4-β-Galp, 3,6-β-Galp and 3,4,6-β-Galp and branched chains that contained two arabinan (R1 and R2) and two heteropolysaccharide (R3 and R4) side chains. The branching degree of HEPN-1 was 0.52. Within the range of doses (75–300 μg/mL), HEPN-1 increased the enzyme activity of SOD, CAT and GSH-Px and decreased the MDA level in H2O2-induced RAW 264.7 cells in a dose-dependent manner. After 6 weeks of intragastric administration, 300 mg/kg HEPN-1 considerably improved the learning and memory deficits in mice and the antioxidant enzyme system. Moreover, the MDA formation in D-gal-induced aging mice was inhibited, possibly partly via the activation of the PI3K/Akt and Nrf2/HO-1 signalling pathways. Therefore, HEPN-1 could serve as a potential natural antioxidant to prevent aging.

Phenothiazine-based virtual screening, molecular docking, and molecular dynamics of new trypanothione reductase inhibitors of Trypanosoma cruzi.

Phenothiazine derivatives can unselectively inhibit the trypanothione-dependent antioxidant system enzyme trypanothione reductase (TR). A virtual screening of 2163 phenothiazine derivatives from the ZINC15 and PubChem databases docked on the active site of T. cruzi TR showed that 285 compounds have higher affinity than the natural ligand trypanothione disulfide. 244 compounds showed higher affinity toward the parasite's enzyme than to its human homolog glutathione reductase. Protein-ligand interaction profiling predicted that the main interactions for the top scored compounds were with residues important for trypanothione disulfide binding: Phe396, Pro398, Leu399, His461, Glu466, and Glu467, particularly His461, which participates in catalysis. Two compounds with the desired profiles, ZINC1033681 (Zn_C687) and ZINC10213096 (Zn_C216), decreased parasite growth by 20 % and 50 %, respectively. They behaved as mixed-type inhibitors of recombinant TR, with Ki values of 59 and 47 μM, respectively. This study provides a further understanding of the potential of phenothiazine derivatives as TR inhibitors.

Heavy Metal Induced Oxidative Stress Mitigation and ROS Scavenging in Plants.

Although trace elements are essential for life, environmental contamination due to metal accumulation and overuse in various sectors, such as healthcare, agriculture, industry, and cosmetics, poses significant health concerns. Exposure of plants to heavy metals leads to the overproduction of reactive oxygen species (ROS) due to their ability to change mitochondrial membrane permeability and restrict the action of ROS clearance enzymes in the cellular antioxidant system. The interaction of ROS with cellular membranes, heavy-metal-induced interactions directly or indirectly with different macromolecules, and signaling pathways leads to the accumulation of environmental pollutants and oxidative stress in exposed organisms. The heavy metal-ROS-cell signaling axis affects various pathological processes such as ATP depletion, excess ROS production, mitochondrial respiratory chain damage, decoupling of oxidative phosphorylation, and mitochondrial death. This review focuses on discussing the toxic effects of different heavy metals on plants, with particular emphasis on oxidative stress, its consequences, and mitigation strategies.

Oxidative Stress in Healthy and Pathological Red Blood Cells.

Red cell diseases encompass a group of inherited or acquired erythrocyte disorders that affect the structure, function, or production of red blood cells (RBCs). These disorders can lead to various clinical manifestations, including anemia, hemolysis, inflammation, and impaired oxygen-carrying capacity. Oxidative stress, characterized by an imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense mechanisms, plays a significant role in the pathophysiology of red cell diseases. In this review, we discuss the most relevant oxidant species involved in RBC damage, the enzymatic and low molecular weight antioxidant systems that protect RBCs against oxidative injury, and finally, the role of oxidative stress in different red cell diseases, including sickle cell disease, glucose 6-phosphate dehydrogenase deficiency, and pyruvate kinase deficiency, highlighting the underlying mechanisms leading to pathological RBC phenotypes.

Antihyperlipidemic effect of bread fortified with potato peel powder against Triton X-100-induced hyperlipidemia in male albino rats

The present investigation aimed to improve the nutritional and healthy values and evaluate the influence of bread fortified with dried potato peels (BPP) on Triton X-100-induced hyperlipidemia in male albino rats. The findings demonstrated that BPP lowered hepatic triglycerides and total cholesterol while increasing high-density lipoprotein (HDL-C). BPP exhibited potential lipid-lowering and hepatoprotective actions that were generated by the reduction of oxidative damage and preservation of the non-enzymatic and enzymatic antioxidant systems compromised by hyperlipidemic condition. Furthermore, BPP considerably enhanced the mRNA expression of AMPKα (AMP-activated protein kinase-alpha), suppressed the expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase alpha (ACCα), and decreased the mRNA expression of the adipogenic transcription factor SREBP-1c (sterol regulatory element-binding protein-1c), which are essential regulators of hepatocyte lipid metabolism. A histopathological assessment of the liver confirmed the results. In conclusion, this investigation revealed a positive impact of bread fortified with BPP therapy in preventing hyperlipidemia.

Analyzing the impacts of cadmium alone and in co-existence with polypropylene microplastics on wheat growth.

Heavy metals typically coexist with microplastics (MPs) in terrestrial ecosystems. Yet, little is known about how the co-existence of heavy metals and MPs affect crops. Therefore, this study aimed to evaluate the impact of cadmium (Cd; 40 mg/L) alone and its co-existence with polypropylene (PP)-MPs (50 and 100 µm) on seed germination, root and shoot growth, seedling dry weight (DW), and antioxidant enzyme activities of wheat. The study demonstrated that the germination rate of wheat did not vary significantly across treatment groups. Yet, the inhibitory impact on wheat seed germination was strengthened under the co-existence of Cd and PP-MPs, as the effect of a single treatment on seed germination was non-significant. The germination index and mean germination time of wheat seeds were not affected by single or combined toxicity of Cd and PP-MPs. In contrast, Cd and PP-MPs showed synergistic effects on germination energy. Wheat root and shoot length were impeded by Cd alone and in combination with PP-MPs treatments. The DW of wheat seedlings showed significant change across treatment groups until the third day, but on the seventh day, marginal differences were observed. For example, on third day, the DW of the Cd treatment group increased by 6.9% compared to CK, whereas the DW of the 100 µm PP-MPs+Cd treatment group decreased by 8.4% compared to CK. The co-occurrence of Cd and PP-MPs indicated that 50 μm PP-MPs+Cd had an antagonistic impact on wheat seedling growth, whereas 100 μm PP-MPs+Cd had a synergistic impact due to the larger size of PP-MPs. The antioxidant enzyme system of wheat seeds and seedlings increased under single Cd pollution, while the activities of superoxide dismutase, catalase, and peroxidase were decreased under combined pollution. Our study found that Cd adversely affects wheat germination and growth, while the co-existence of Cd and PP-MPs have antagonistic and synergistic effects depending on the size of the PP-MPs.

Liver protective effect of chloroform extract of Bauhinia purpurea leaves is attributed partly to its antioxidant action and the presence of flavonoids

Context Bauhinia purpurea L. (Fabaceae) is used in the Ayurvedic system to treat various oxidative-related ailments (e.g., wounds, ulcers etc.). Therefore, it is believed that the plant also has the potential to alleviate oxidative-related liver damage. Objective This study elucidates the hepatoprotective activity of chloroform extract of B. purpurea leaves (CEBP) in paracetamol (PCM)-induced liver injury (PILI) rats. Materials and methods Male Sprague-Dawley rats (n = 6) were pre-treated once daily (p.o.) with CEBP (50–500 mg/kg) for seven consecutive days before being administered (p.o.) a hepatotoxic agent, 3 g/kg PCM. Liver enzyme levels were determined from the collected blood, while the collected liver was used to determine the activity of endogenous antioxidant enzymes and for histopathological examination. CEBP was also subjected to radical scavenging assays and phytochemical analysis. Results CEBP significantly (p < 0.05) reversed the toxic effect of PCM by increasing the serum levels of AST and ALT, and the activity of endogenous catalase (CAT) and superoxide dismutase (SOD) while reducing the liver weight/body weight (LW/BW) ratio. Other than low TPC value and radical scavenging activity, CEBP had a high antioxidant capacity when evaluated using the oxygen radical absorbance capacity (ORAC) assay. UHPLC-ESI-MS analysis of CEBP showed the presence of flavonoids. Discussion and conclusions CEBP exerts its hepatoprotective activity through a non-free radical scavenging pathway that involves activation of the endogenous enzymatic antioxidant defense system. Further study is needed to identify the responsible bioactive compounds before the plant can be developed as a future alternative hepatoprotective medicament for clinical use.

Comparative studies on the effect of salinity and drought stress on enzymatic antioxidant defense system of two maize (&lt;i&gt;Zea mays&lt;/i&gt; l.). varieties

Soil salinization and drought are serious threat to crop productivity and predicted to increase in face of global climate change. Studies have shown that as much as the 12 billion US dollar will be lost globally each year, due to the reduction in agricultural production from drought and salt-affected areas. Maize is an economically important cereal crop affected by high salinity and drought stress, maize seedling was subjected to 50 mM, 100 mM and 150 mM NaCl and 4, 6 and 8 days to emulate high soil salinity and drought stress. Root and mature leaves were harvested after 21 days of sowing. High salinity induced oxidative stress in the root and mature leaves. The root and matured leaves showed increased malondialdehyde (MDA) and the hydrogen peroxide (H2O2) concentration at 50, 100 and 150 mM NaCl and 4, 6, and 8 days of drought strss. Activities of enzymatic antioxidants, Catylase (CAT, E .C 1.11.1.6) increase in all organs of salt treated maize seedling, while superoxide dismutase (SOD, 1.15.1.1) and peroxidase (POX, E.C. 1.11.1.7) increased specifically in mature leaves. This indicates a possible role of reactive oxygen species (ROS) in the systemic signaling from roots to leaves, allowing leaves to activate their defense mechanism for better protection against salt and drought stress.

Novel Therapeutic Approaches to Liver Fibrosis Based on Targeting Oxidative Stress.

Chronic liver disease (CLD) constitutes a growing global health issue, with no effective treatments currently available. Oxidative stress closely interacts with other cellular and molecular processes to trigger stress pathways in different hepatic cells and fuel the development of liver fibrosis. Therefore, inhibition of reactive oxygen species (ROS)-mediated effects and modulation of major antioxidant responses to counteract oxidative stress-induced damage have emerged as interesting targets to prevent or ameliorate liver injury. Although many preclinical studies have shown that dietary supplements with antioxidant properties can significantly prevent CLD progression in animal models, this strategy has not proved effective to significantly reduce fibrosis when translated into clinical trials. Novel and more specific therapeutic approaches are thus required to alleviate oxidative stress and reduce liver fibrosis. We have reviewed the relevant literature concerning the crucial role of alterations in redox homeostasis in different hepatic cell types during the progression of CLD and discussed current pharmacological approaches to ameliorate fibrosis by reducing oxidative stress focusing on selective modulation of enzymatic oxidant sources, antioxidant systems and ROS-mediated pathogenic processes.

Enhancement of salt tolerance of transgenic Arabidopsis thaliana by Zostera japonica DnaJ gene

Abstract Soil salt damage has become one of the main biological stresses affecting plant seed germination, crop growth and yield. Salt damage can lead to the accumulation of superoxide anion, hydrogen peroxide and hydroxyl free radicals in plants, and a large amount of accumulated reactive oxygen species will cause the oxidation of lipids, proteins and nucleic acids and then cause cell damage. In this experiment, the seedlings and adult plants of transgenic Arabidopsis with overexpression of Zostera japonica (Z. japonica) DnaJ gene ZjDjB1 were used as materials. Wild-type and transgenic ZjDjB1 Arabidopsis were treated with 100 mM and 200 mM NaCl and root length, fresh weight, leaf water content and dry weight, physiological indexes and antioxidant system enzyme activities were measured. The results showed that overexpression of Z. japonica DnaJ gene ZjDjB1 could significantly alleviate the damage caused by salt stress to transgenic ZjDjB1 Arabidopsis seedlings and adult plants. The results showed that overexpression of Z. japonica DnaJ gene ZjDjB1 could reduce the content of MDA and O2-, increase the content of proline and activate the enzyme activity of antioxidant system under salt stress, to reduce the damage of salt stress to plants.

Linking the role of melatonin in plant stress acclimatization

Melatonin is a derivative of tryptophan and consists of a conserved domain present ubiquitously from bacteria to higher organisms. Melatonin is an emerging pleiotropic plant growth hormone that is pivotal in coping with various biotic and abiotic stress conditions. It regulates downstream signaling transduction that modulates plants' physiological and biochemical pathways. Melatonin can be externally applied and could strengthen the stress tolerance mechanism of plants by enhancing ROS-scavenging enzymatic and non-enzymatic antioxidant defense systems. Which consequently exhibits lower lipid peroxidation, MDA content, greater enzyme activity, metabolic pool, ion homeostasis, and plasma membrane integrity under stress conditions. In addition, melatonin protects photosynthetic machinery by maintaining cell membrane stability and chlorophyll recovery. It also stimulates the electron transport chain during photosynthesis and D1 protein biosynthesis and maximizes the photochemistry efficiency (Fv/Fm) of photosystem II and photochemical quenching. Besides abiotic stress, melatonin plays a significant role in biotic stress tolerance. This review emphasizes Melatonin as a stress protectant under biotic and abiotic stress. Further, we have highlighted integrating advanced biotechnology tools with recent information for the possible application of melatonin in the current scenario of changing climate.

SkQ1 Improves Immune Status and Normalizes Activity of NADPH-Generating and Antioxidant Enzymes in Rats with Adjuvant-Induced Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a severe systemic autoimmune inflammatory disease. Oxidative stress and excessive formation of reactive oxygen species (ROS) by the mitochondria are considered as the central pathogenetic mechanisms of connective tissue destruction and factors responsible for a highly active inflammatory process and autoimmune response. The aim of this work was to evaluate the effect of mitochondria-targeted antioxidant 10-(6'-plastoquinonyl)decyltriphenylphosphonium (SkQ1) on the immune status, intensity of free radical-induced oxidation, and functioning of the antioxidant system (AOS) and NADPH-generating enzymes in rats with the adjuvant-induced RA. Laboratory animals were divided into 4 groups: control group; animals with RA; animals injected intraperitoneally with SkQ1 at the doses of 1250 and 625 nmol/kg, respectively, every 24 h for 8 days starting from day 7 of RA development. Tissue samples for analysis were collected on day 15 of the experiment. Erythrocyte sedimentation rate, the content of circulating immune complexes, and the concentration of class A, M, and G immunoglobulins were determined by enzyme immunoassay. The intensity of free radical-induced oxidation was evaluated based on the assessment of the iron-induced biochemiluminescence, diene conjugate content, and activity of aconitate hydratase. Enzymatic activity and metabolite content in the tissue samples were analyzed spectrophotometrically. It was shown that the development of RA was associated with an increase in the manifestation of immune response markers and intensity of free radical-induced oxidation, as well as with disruption of the AOS functioning and activation of NADPH-generating enzymes. SkQ1 administration resulted in a dose-dependent changes in the oxidative status indicators towards the control values and normalization of the immune status parameters. SkQ1 decreased the level of mitochondrial ROS, resulting in the suppression of the inflammatory response, which might cause inhibition of free radical generation by immunocompetent cells and subsequent mitigation of the oxidative stress severity in the tissues.

Combined effect of trehalose and spermidine to alleviate zinc toxicity in Vigna radiata.

Zinc toxicity is affecting the growth and yield of major crops plants throughout globe by reducing key metabolic processes. In this backdrop, experiments were conducted to evaluate the influence of exogenous supplementation of trehalose (500 µM Treh) and spermidine (500 µM Spd) in alleviating the damaging effects of zinc toxicity (100 µM ZnSO4) in Vigna radiata. Growth, chlorophyll and photosynthesis were reduced due to Zn toxicity; however, exogenous supplementation of trehalose and spermidine not only increased the parameters but also alleviated the decline to considerable levels. Toxicity of zinc increased H2O2, lipid peroxidation and electrolyte leakage by 100.43%, 84.53% and 134.64%, respectively, and application of trehalose and spermidine a reduction of 29.32%, 39.09% and 44.91%, respectively, over the zinc-treated plants. Application of trehalose and spermidine increased the activity of nitrate reductase and the content of nitrogen concomitant with alleviation of the decline caused due to zinc toxicity. The activity of antioxidant system enzymes superoxide dismutase, catalase and the enzymes of ascorbate-glutathione cycle was significantly enhanced due to trehalose and spermidine application. Proline, glycine betaine and activity of γ-glutamyl kinase increased maximally by 281.84%, 126.21% and 181.08%, respectively, in plants treated with zinc + trehalose + spermidine over control. Significant enhancement in the content of total phenols and flavonoids was observed due to the treatment of trehalose and spermidine individually as well as combinedly. Application of trehalose and spermidine reduced the content of methylglyoxal by up-regulating the activity of glyoxylase cycle enzymes. In addition under zinc toxicity conditions, the content of zinc declined in trehalose- and spermidine-treated plants.

A comprehensive assessment of redox balance in small for gestational age newborns and their mothers.

The objective of this study was to assess oxidative stress in small for gestational age (SGA) newborns and their mothers by evaluating intra- and extracellular thiol homeostasis and the quantification of major oxidants and antioxidants. A total of 75 mothers and their 75 newborns (43 SGA) were enrolled in this study. Thiol-disulfide homeostasis, serum myeloperoxidase, catalase, total oxidant, and antioxidant status were analyzed. Additionally, erythrocytic glutathione (GSH) homeostasis was measured. Although native and total thiol levels were decreased, disulfide levels were increased in SGA groups. Additionally, myeloperoxidase activity and total oxidant status levels were significantly elevated whereas total antioxidant status levels and enzymatic antioxidant systems were diminished in SGA groups. Similarly, intra-erythrocytic GSH homeostasis was shifted in favor of oxidants in SGA groups. Our results demonstrate that insufficient antioxidant systems in mothers and a robust source of oxidative stress in SGA might contribute to the pathophysiology of SGA births.