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Pro-oxidative shift in redox balance, usually termed as "oxidative stress", can lead to different cell responses depending on its intensity. Excessive accumulation of reactive oxygen species ("oxidative distress") can cause DNA, lipid and protein damage. Physiological oxidative stimulus ("oxidative eustress"), in turn, can favor cell proliferation and differentiation – the processes of paramount importance primarily for stem cells. Functions of antioxidant enzymes in cells is currently a focus of intense research, however the role of different antioxidant pathways in pluripotent cell responses to oxidative distress/eustress is still under investigation. In this study, we assessed the contribution of the thioredoxin reductase (TrxR)-dependent pathways to maintaining the redox homeostasis in human induced pluripotent stem cells and their differentiated progeny cells under basal conditions and under conditions of oxidative stress of varying intensity. Employing the genetically encoded H 2 O 2 biosensor cyto-HyPer and two inhibitors of thioredoxin reductase (auranofin and Tri-1), we show that the reduced activity of TrxR-dependent enzymatic systems leads to the non-cytotoxic disruption of thiol-disulfide metabolism in the cytoplasm of both pluripotent and differentiated cells under basal conditions. Quantifying the cytoplasmic concentrations of peroxide establishing in H 2 O 2 -stressed cells, we demonstrate that TrxR-dependent pathways contribute to the antioxidant activity in the cell cytoplasm under conditions of mild but not severe oxidative stress in both cell lines tested. The observed effects may testify about a conservative role of the TrxR-controlled enzymatic systems manifested as a response to physiological redox stimuli rather than a protection against the severe oxidative stress. • Inhibition of TrxR causes non-cytotoxic increase in the basal thiol oxidation in iPSCs. • Inhibition of TrxR decreases antioxidant capacity of iPSCs under mild oxidative stress. • Resistance of iPSC to severe oxidative stress is not affected by the TrxR inhibition. • Differentiated progenies of iPSCs respond to TrxR inhibition similar to iPSCs. [ABSTRACT FROM AUTHOR]

Rice, a staple food for more than half of the world population, is an affordable source of calorie, satisfying more than 20% of the calorie requirement on a global scale. Its cultivation is threatened by multiple challenges, including droughts, floods, salinity, and depletion of micronutrients pool or enrichment of micronutrients at a toxic level. Inorganic minerals play a crucial role in regulating different metabolic activities in plants. Iron (Fe) is among such essential micronutrients involved in a variety of metabolic processes, such as photosynthesis, chlorophyll synthesis, mitochondrial respiration, nucleic acids synthesis/repair, and maintenance of chloroplast ultrastructure/function. Iron is also a component of essential proteins like heme and acts as a cofactor of certain enzymes working as an accepter or a donor of protons. Iron deficiency and excess are the most prevalent soil-related micronutrient disorders in lowland rice production systems. Phytotoxicity caused by large concentrations of ferrous Fe (Fe2+) in the soil solution in reduced soil and substantial associated yield losses could pose a serious threat to regional and global food security. Traditional rice cultivation practice under continuous flooding notably features an ideal reduction potential for prevalent and rapidly progressing Fe toxicity primarily affecting lowland rice production. Advancements in rice cultivar development with improved tolerance and adjustments of proper management strategies to address Fe toxicity at the field level have been quite challenging due to a poor understanding of plant internal tolerance mechanism and soil properties regulating Fe availability and toxicity. Rice varieties for low pH tolerance, developed in the past through conventional breeding approaches, were somewhat indirectly contributed to Fe toxicity tolerance. During the past two decades, a considerable breakthrough has been made in understanding the genetics, physiology, and biomolecular aspects of Fe toxicity tolerance in rice. Extensive studies across different Fe-toxic environments have also highlighted the marginal difference among Fe deficiency, adequacy, and toxicity ranges both in the soil and plant systems. Despite the complexity, there is a necessity for systematic understanding and integration between the available knowledge of soil Fe regulation and transport as well as plant internal tolerance mechanism for stepping forward in strategizing rice improvement programs. Hence, an in-depth understanding of Fe availability, uptake, and translocation from soil to plant is needed. Therefore, the present review highlights an intricate approach to congregate the excess Fe regulation in soil coupled with cellular Fe toxicity tolerance of rice and management options in alleviating the negative effects of Fe toxicity on the performance of lowland rice, that could potentially offer invaluable information for rice improvement programs. [ABSTRACT FROM AUTHOR]

This study examined the effects of liquid fertilizer management on the aroma, grain quality, nutrient status, and antioxidant response of the aromatic rice varieties Yuxiangyouzhan (YXYZ) and Xiangyaxiangzhan (XYXZ) in field trials in 2019 and 2020. The application of liquid fertilizer management treatments augmented the 2-acetyl-1-pyrroline (2AP) contents. The liquid fertilizer management treatments increased the activity of antioxidant enzymes in the leaves and the contents of nutrients (nitrogen, phosphorus, and potassium) in different plant tissues, enhanced the protein content, and reduced the chalkiness in the grains. The accumulation of 2AP responded positively to the modulation of nutrient content, antioxidant response parameters, grain quality, and attributes related to the biosynthesis of 2AP. Application of 90–45–7.5 kg N ha−1 liquid fertilizer when the basal-tillering-panicle splits was the most effective fertilization treatment in improving the contents of 2-acetyl-1-pyrroline with the highest average 2AP content of 124.34 μg kg−1, which can be attributed to the regulating of grain quality, nutrient content, antioxidant response, and attributes related to 2AP biosynthesis. • Liquid fertilizer management increased the 2AP content and antioxidant activity. • Liquid fertilizer management improved the grain quality. • POD and CAT activities positively regulate 2AP content. • Nutrient content in aromatic rice tissues can directly or indirectly regulate the accumulation of 2AP. [ABSTRACT FROM AUTHOR]

Abstract Because of the high protein content and rich meat quality of crayfish Procambarus clarkii , it has become widely popular in China in recent years and has a high economic value. When P. clarkii is stimulated by heavy metals, it reacts to oxidation. P. clarkii has evolved antioxidant defense systems, including antioxidant enzymes such as catalase (CAT). The hexavalent form of Cr (VI) is a pathogenic factor that is of particular concern in aqueous systems because of its great toxicity to living organisms. In this study, we characterized the transcriptome of P. clarkii using a RNA sequencing method and performed a comparison between K 2 Cr 2 O 7 -treated samples and controls. In total, 34,237 unigenes were annotated. We identified 5098 significantly differentially expressed genes (DEGs), including 2536 and 2562 were significantly up-regulated and down-regulated, respectively. In addition, quantitative real time-PCR (qRT-PCR) confirmed the up-regulation of a random selection of DEGs. Our results contribute to a more comprehensive understanding of the antioxidant defense system used by P. clarkii in response to heavy metal stress. Highlights • The chromium-stimulated hepatopancreas transcriptome of Procambarus clarkii was constructed. • Totally 34,237 unigenes was annotated from the transcriptome. • Totally 5098 DGEs were identified including 2536 up- and 2562 down-regulated unigenes. [ABSTRACT FROM AUTHOR]

Cadmium tellurium quantum dots (CdTe QDs) as one of the most widely used QDs have been reported the toxicity and biosafety in recent years, little work has been done to reduce their toxicity however. Based on the mechanisms of toxicity of CdTe QDs on liver target organs such as oxidative stress and apoptosis previously reported by other researchers, we investigated the mechanism of action of trace element selenium (Se) to mitigate the hepatotoxicity of CdTe QDs. The experimental results showed that Se-Met at 40–140 μg L−1 could enhance the function of intracellular antioxidant defense system and the molecular structure of related antioxidant enzymes by reduce the production of ROS by 45%, protecting the activity of antioxidants and up-regulating the expression of selenoproteins with antioxidant functions, Gpx1 increase 225% and Gpx4 upregulated 47%. In addition, Se-Met could alleviate CdTe QDs-induced apoptosis by regulating two apoptosis-inducing factors, as intracellular caspase 3/9 expression levels were reduced by 70% and 87%, decreased Ca2+ concentration, and increased mitochondrial membrane potential measurements. Overall, this study indicates that Se-Met has a significant protective effect on the hepatotoxicity of CdTe QDs. Se-Met can be applied to the preparation of CdTe QDs to inhibit its toxicity and break the application limitation. [Display omitted] ● Combining cellular and molecular levels to study the role and regulation mechanism of Se-Met in adverse effects induced by CdTe QDs. ● Se-Met maintains redox balance and mitochondrial function by protecting the structural changes of SOD/CAT and enhancing the antioxidant function of selenoproteins, reduces the level of apoptosis induced by CdTe QDs, and attenuates the toxicity of CdTe QDs on hepatocytes. [ABSTRACT FROM AUTHOR]

The present study deals with impact of varied doses of arsenite (As III ; 50, 100 and 150 µM) and arsenate (As V ; 50, 100 and 150 mM) on growth, photosynthetic pigments, photochemistry of photosystem II, oxidative biomarkers, (O 2 • ¯, H 2 O 2 and MDA equivalents contents) and activity of antioxidant enzymes in diazotrophic cyanobacterium Nostoc muscorum after 48 and 96 h of the treatments. The reduction in growth, pigment contents (Chl a , Phy and Car) and PS II photochemistry was found to increase with enhanced accumulation of test metal in cells, and the damaging effect on photosynthetic pigments showed the order (Phy > chl a > Car). The negative effect on PS II photochemistry was due to significant decrease in the value of JIP kinetics ϕP 0 , F V /F 0 , ϕE 0 ,Ψ 0 and PI ABS except F 0 /F V and significant rise in values of energy flux parameters such as ABS/RC, TR 0 /RC, ET 0 /RC and DI 0 /RC. Both the species of arsenic caused significant rise in oxidative biomarkers as evident by in vitro and in vivo analysis of (O 2 • ¯, H 2 O 2 and MDA equivalents contents) despite of appreciable rise in the activity antioxidative enzymes such as SOD, POD, CAT and GST. The study concludes that in among both forms of arsenic, arsenite effect was more dominant on growth, photosynthetic pigments; oxidative stress biomarkers as evident by weak induction of anti-oxidative defense system to overcome the stress as compared to arsenate. [ABSTRACT FROM AUTHOR]

During its life cycle, plant has to cope with a number of abiotic stresses including cadmium stress. Cadmium (Cd) is highly toxic to plant and greatly influences its growth and entire metabolism. Antioxidants have to enable plant to beat such stresses. Therefore, effects of ascorbate (AsA), proline (Pro) and glutathione (GSH) applied, as seed soaking solutions, singly or in a sequence on cucumber transplant growth, physio-biochemical attributes and antioxidant defense system activity were investigated under 2 mM Cd stress. Adding Cd to transplants in irrigation water reduced photosynthetic efficiency, and nutrient (K + and Ca 2+ ) contents, while increased the activity of defense systems (non-enzymatic and enzymatic antioxidants) and Cd 2+ contents in roots and leaves. Exogenous AsA, Pro and GSH applied singly or in a sequence improved transplant growth (e.g., shoot length, leaf area, shoot fresh weight and shoot dry weight), photosynthetic efficiency (i.e., SPAD chlorophyll, Fv/Fm and PI), transplant health (i.e., increased leaf MSI and RWC, and decreased root and leaf Cd 2+ contents), antioxidant defense systems activity (enzymatic; superoxide dismutase, catalase, glutathione reductase and ascorbate peroxidase, and non-enzymatic; Pro, AsA and GSH antioxidants) and nutrient (K + and Ca 2+ ) contents. These positive results were obtained under irrigation with or without Cd, AsA. Sequenced AsA-Pro-GSH was the best treatment of which this study recommends to use, followed by GSH treatment, for growing cucumber transplants under Cd stress. [ABSTRACT FROM AUTHOR]

The manganese contamination has become a global problem, recently, because it is perceived as a real threat to the human health and the environment. It is well-known that overexposure to Mn 2+ may have negative physiological effects on fish and other organisms inhabiting heavy metal polluted waters. To the best of our knowledge, studies relating with manganese effects on fish antioxidant enzyme response in the blood, immunocompetence and erythron profile alteration, are scarce. In this study, the acute sub-lethal effects of manganese on blood antioxidant response, immune status and erythron profile were determined by exposing the freshwater model organism, Carassius auratus , to two doses of this metal (3.88 ± 0.193 mg/L and 7.52 ± 0.234 mg/L Mn 2+ ) for 96 h. Significant increases in blood antioxidant enzyme activity like superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST), were observed in fish exposed to manganese. Furthermore, plasmatic glucose and cortisol levels increased, while total protein decreased significantly. White blood cell differential count revealed a significant increase in monocyte and neutrophil number and a significant decrease of lymphocyte's number in fish exposed to manganese compared with those of control group. That can be considered as a clear evidence of altered immune system. Measured of erythron profile revealed a significant increasing of cellular and nuclear alteration of red blood cells, with karryorhectic, dividing and micronucleated erythrocytes in exposed fish, indicating the cytotoxic and genotoxic effects Mn 2+ ions. Our data shown also that manganese could trigger antioxidant response, modulate immune response and induce erythron profile modification leading to eryptosis, compromising the blood oxygen carrying capacity, and overall health status in fish. This may suggest those parameters consider as useful biomarkers for monitoring effects of sub-lethal metal exposure on fish. [ABSTRACT FROM AUTHOR]

Aluminium (Al) toxicity is the most important soil constraint for plant growth and development in acid soils (pH < 5.5) globally in agricultural regions. Boron (B) is an essential micronutrient for the growth and development of higher plants. The results of previous studies propose that B might ameliorate Al toxicity; however, none of the studies have been conducted on trifoliate orange to study this effect. Thus, a study was carried out in hydroponics comprising of two different Al concentrations, 0 and 400 μM. For every concentration, two B treatments (0 and 10 μM as H 3 BO 3 ) were applied to investigate the B-induced alleviation of Al toxicity and exploring the underneath mechanisms. The results revealed that Al toxicity under B deficiency severely hampered the root growth and physiology of plant, caused oxidative stress and membrane damage, leading to severe root injury and damage. However, application of B under Al toxicity improved the root elongation and photosynthesis, while reduced Al uptake and mobilization into plant parts. Moreover, B supply regulated the activities of antioxidant enzymes, proline, secondary metabolites (phenylalanine ammonia lyase and polyphenol oxidase) contents, and stabilized integrity of proteins. Our study results imply that B supply promoted root growth as well as defense system by reducing reactive oxygen species (ROS) and Al concentrations in plant parts thus B induced alleviation of Al toxicity; a fact that might be significant for higher productivity of agricultural plants grown in acidic conditions. [ABSTRACT FROM AUTHOR]

Chitosan (CTS) induces plant tolerance against several abiotic stresses, including salinity and drought exposure. However, the role of CTS in cadmium (Cd)-induced stress amelioration is largely unknown. In the present study, a hydroponic pot experiment was conducted to study the roles of CTS with different molecular weight (Mw) (10 kDa，5 kDa and 1 kDa) in alleviating Cd toxicity in edible rape ( Brassica rapa L .). The results showed that Cd stress significantly decreased plant growth, leaf chlorophyll contents and increased the malondialdehyde (MDA) level in rape leaves. Foliar application of CTS promoted the plant growth and leaf chlorophyll contents, and decreased the malondialdehyde (MDA) level in edible rape leaves under Cd stress. The alleviation effect of CTS on toxicity was depended on its Mw and CTS with Mw of 1 kDa showed the best activity. Spraying 1 kDa CTS onto the leaves of edible rape under Cd-toxicity could decrease shoot Cd 2+ concentration and improve photosynthetic characteristics of edible rape. Moreover, 1 kDa CTS also significantly enhanced non-enzymatic antioxidants (ascorbic acid) and enzyme activities (superoxide dismutase, catalase and guaiacol peroxidase) under Cd stress. Based on these findings, it can be concluded that application of exogenous CTS could be an effective approach to alleviate the harmful effects of Cd stress and could be explored in an agricultural production system. [ABSTRACT FROM AUTHOR]

We investigated the associations between environmental exposure to lead and a repertoire of cytokines in seminal plasma of males with normal semen profile according to the WHO criteria. Based on the median lead concentration in seminal plasma, 65 samples were divided into two groups: low (LE) and high exposure to lead (HE). Differences in semen volume and the pH, count, motility and morphology of sperm cells were not observed between the examined groups. The total oxidant status value and the level of protein sulfhydryl groups as well as the activities of manganese superoxide dismutase and catalase were significantly higher in the HE group, whereas the total antioxidant capacity value and the activities of glutathione reductase and glutathione-S-transferase were depressed. IL-7, IL-10, IL-12, and TNF-α levels were significantly higher in the HE group compared with the LE group. Environmental exposure to lead is sufficient to induce oxidative stress in seminal plasma and to modulate antioxidant defense system. [ABSTRACT FROM AUTHOR]

Abstract: This study investigates largely unexplored physiological/biochemical strategies adopted by salt marsh macrophyte Halimione portulacoides (L.) Aellen for its adaptation/tolerance to environmental mercury (Hg)-exposure in a coastal lagoon prototype. To this end, a battery of damage (hydrogen peroxide, H2O2; thiobarbituric acid reactive substances, TBARS; electrolyte leakage, EL; reactive carbonyls; osmolyte, proline) and defense [ascorbate peroxidase, APX; catalase, CAT; glutathione peroxidase, GPX; glutathione sulfo-transferase, GST; glutathione reductase, GR; reduced and oxidized glutathione (GSH and GSSG, respectively), and GSH/GSSG ratio] biomarkers, and polypeptide patterns were assessed in H. portulacoides roots and leaves at reference (R) and the sites with highest (L1), moderate (L2) and the lowest (L3) Hg-contamination gradients. Corresponding to the Hg-burdens, roots and leaves exhibited a differential modulation of damage- and defense-endpoints and polypeptide-patterns. Roots exhibiting the highest Hg-burden (at L3) failed to maintain a coordination among enzymatic-defense endpoint responses which resulted into increased oxidation of reduced glutathione (GSH) pool, lowest GSH/GSSG (oxidized) ratio and partial H2O2-metabolism. In contrast, the highest Hg-burden exhibiting leaves (at L1) successfully maintained a coordination among enzymatic-defense endpoints responses which resulted into decreased GSH-oxidation, enhanced reduced GSH pool and GSH/GSSG ratio and lower extent of damage. Additionally, increased leaf-carotenoids content with increasing Hg-burden implies its protective function. H. portulacoides leaf-polypeptides did not respond as per its Hg-burden but the roots did. Overall, the physiological/biochemical characterization of below (roots)- and above (leaves)-ground organs (studied in terms of damage and defense endpoints, and polypeptides modulation) revealed the adaptive responses of H. portulacoides to environmental Hg at whole plant level which cumulatively helped this plant to sustain and execute its Hg-remediation potential. [Copyright &y& Elsevier]

Abstract: Changes in activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and non-enzymatic antioxidant reduced glutathione (GSH) content and levels of Lipid peroxidation (LPO) in gill, liver, brain and intestine of juvenile carp (Cyprinus carpio) were evaluated after exposure to different concentrations (0.5, 5.0 and 50.0mg/L) of waterborne nano-ZnO for 1, 3, 7, 10 and 14 day. The results showed that the variation trendency of antioxidant defense systems and LPO levels would be more significant with increasing concentration and exposure time. 50.0mg/L nano-ZnO caused significant decrease of several enzymes activities and GSH content and increase of LPO level. As a result, these biomarkers were all appropriate for monitoring oxidative stress status of fish after exposure to nano-ZnO. Gill, liver and brain might be more sensitive response organs, being intestine the least altered organ. Further ecotoxicological evaluation should be made concerning the risk of nano-ZnO on aquatic environment. [Copyright &y& Elsevier]

Abstract: Tests of acute toxicity were performed on the most common species of aquarium fish, Poecilia reticulata. Guppies (P. reticulata) were exposed to progressive concentrations of methyl parathion (MP) and chlorpyrifos (CPF); a semi-static method according to guidelines of OECD was used. Tests of acute toxicity were conducted using 10 fish for each separate concentration and for the control group. The results were subjected to probit analysis to determine the 96h LC50 values. The 96h LC50 values of MP and CPF to P. reticulata were 8.48ppm/L (5.98–10.89) and 0.176ppm/L (0.313–0.224) respectively. In addition, behavioral changes at each concentration were observed for the individual fish. Fish were exposed for 96h to different sublethal concentrations of MP and CPF (¼ LC50, 1/8 LC50 and 1/10 LC50) and their oxidative stress-induction potential was estimated in brain, liver and gills of fish. MDA content is induced in all tissues but maximum rise was observed in gills (161% and 153% for MP and CPF respectively). With regard to antioxidant defense system (ADS), GSH level decreased in the brain, liver and gills of tissues of MP treated fishes (22%, 6% and 13% respectively) and showed increase in brain and gills CPF treated (23% and 21% respectively). CAT, GST, GR and SOD levels fluctuated in all treatment groups relative to the control. Brain AChE showed dose-dependent inhibition in fish exposed to the higher concentrations reached 45% and 66% for MP and CPF respectively. Collective findings demonstrated that pesticide exposure of fish induced an increase in MDA and fluctuated ADS along with inhibited AChE. These findings may be used as valuable biomarkers for evaluation of water pollution. [Copyright &y& Elsevier]

Abstract: In vertebrates, many studies verified different effects of melatonin in the antioxidant defense system (ADS). In crustaceans, few studies have been conducted to verify this possibility. We verified the melatonin effects in the crab Neohelice granulata using low (0.002 and 0.02pmol/crab) and high (2.0 and 20.0pmol/crab) melatonin dosages in short-term (0.5h) and long-term (9.5h) experiments. We analyzed the antioxidant capacity against peroxyl radicals (ACAP), reactive oxygen species (ROS) concentration, levels of by products of lipid peroxidation (LPO), oxygen consumption (VO2), the activity of glutamate cysteine ligase (γ-GCL) and catalase (CAT) and glutathione content (GSH). Finally, the effects of exogenous melatonin were verified in terms of melatonin and N 1-acetyl-N 2-formyl-5-methoxykynuramine (AFMK) content in the muscles of N. granulata. In short-term experiment and low dosages, melatonin increased the VO2, γ-GCL activity and GSH content (p <0.05) and decreased melatonin content (p <0.05) without effects in ROS, ACAP and LPO (p >0.05). Possibly, melatonin is acting in the ADS increasing its efficiency and/or acting in mitochondrial activity and/or through signaling muscles to increase its consumption. AFMK was only detected in the eyestalk and cerebroid ganglia. In high dosages melatonin effects decreased, possibly by the desensitization of their receptors. In long-term experiment, melatonin decreased ACAP (p <0.05), and CAT activity (p <0.05) in low dosages. In high dosages melatonin reduced VO2 (p <0.05) and increased ACAP (p <0.05), possibly stimulating others components of the ADS. In conclusion, melatonin in the locomotor muscles of N. granulata affects the antioxidant/pro-oxidant balance in a time and dosage dependent manner. [Copyright &y& Elsevier]

A pot experiment was carried out to investigate the effect of exogenous salicylic acid (SA) on the growth, photosynthesis, oxidative stress and responses of chloroplastic antioxidant defense system of maize (Zea mays L.) plants grown in a nickel (Ni)-contaminated soil. The results indicate that exogenous SA significantly decreased the reduction in dry weight, chlorophyll and ¿-carotene contents, and net photosynthetic rate of the Ni-stressed maize, demonstrating an alleviating effect of SA on Ni toxicity of plants. Superoxide anion generation rate, H2O2 and malondialdehyde (MDA) contents, and lipoxygenase (LOX, EC 1.13.11.12) activity significantly increased in the chloroplasts of maize exposed to Ni stress, revealing an oxidative damage occurred in maize chloroplasts, whereas, the values of these parameters were markedly lowered in the SA-treated plants under Ni stress. Application of SA significantly enhanced the activities of superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), dehydroascorbate reductase (DHAR, EC 1.8.5.1) and glutathione reductase (GR, EC 1.6.4.2), and the poll of reduced ascorbate and glutathione in chloroplasts of the Ni-stressed maize. Accordingly, the fact that SA up-regulates the capacity of antioxidant defense system in chloroplasts, thus reducing the oxidative damage, is involved in the SA-induced alleviation of Ni toxicity in maize. [Copyright &y& Elsevier]

In this study, the effects of dichlorvos (DIC) at sublethal concentration on malondialdehyde (MDA) content and antioxidant defense system (ADS) such as reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), and glutathione-S-transferase (GST) in various tissues of rats exposed to 0.0225 and 0.0450 millimole (mmol) DIC in drinking water were administered orally to rats ad libitum for 28 days continuously. MDA significantly increased in all the tissues except in the lungs of rats treated with both dosages of DIC. With regard to the ADS, GR significantly decreased in the erythrocytes whereas it did not change in the other tissues with two dosages of DIC. SOD activity significantly increased in the all tissues treated with both dosages of DIC. GST activity significantly increased in all the tissues except in the erythrocytes, spleen, and lungs treated with 0.0225mmol. Meanwhile, GSH depletion in the liver and heart of rats treated with 0.0225mmol and all the tissues except in the brain and kidney of rats treated with 0.0450mmol of DIC were found to be significant. The observations presented led us to conclude that the administrations of DIC promote MDA content and fluctuate in the ADS in rats during the exposure. [Copyright &y& Elsevier]

Abstract: The toxicity and influence on chronic development regulation of dietary benzoxadiazole as well as the subsequent action on cuticle enzyme and antioxidant defense system in feed-thru housefly larvae are investigated. Dietary benzoxadiazole shows limited larvicidal activity and weak interference on larval pupation, but strong blockage against the succedent eclosion process. It does not change the content ratio of protein/chitin in the larval cuticle, but strongly regulates the constituents of cuticle proteins. Moreover, chitinase activities in the integument of third-instar larvae, in vivo, are enhanced and gradually decreased whereas phenoloxidase activities are inhibited and the inhibitory rates are gradually increased. Glutathione S-transferase activities are strongly improved whilst peroxidase activities decrease from about 42.25% to 17.36%, catalase activities decrease from about 80.31% to 27.98% and superoxide dismutase activities are almost unchanged during the different treatment procedures. Peroxidase SDS–PAGE analysis shows that band photodensities of 200.0 and 10.3kDa proteins in feed-thru larvae are significantly weaker than the corresponding control band. Results suggest that dietary benzoxadiazole might exert strong regulation on larvae cuticle metabolism, interfere with cuticle enzymatic browning and protein sclerotization and weaken the self-protection of larvae against endogenetic oxidative damages. [Copyright &y& Elsevier]

Abstract: This study aims to investigate the effects of the trichloroacetic acid (TCA) on serum marker enzymes [aspartate aminotransferase (AST), alanin aminotransferase (ALT), creatine phosphokinase (CPK), acid phosphatase (ACP), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH)], antioxidant defense systems [Reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] and lipid peroxidation content (Malondialdehyde, MDA) in various tissues of rats. TCA (2000ppm) as drinking water was administered orally to rats (Sprague–Dawley albino) ad libitum for 50 days continuously. TCA treatments caused different effects on the serum marker enzymes, antioxidant defense systems and the MDA content in experimented rats compared to controls. Results showed that TCA caused a significant increase in serum AST, ALT, CPK and ACP activity. The lipid peroxidation end product MDA slightly increased in the erythrocytes, liver and kidney of rats treated with TCA, whereas did not change in the brain. In addition, antioxidant enzyme activity such as CAT and SOD significantly increased in the brain, liver and kidney tissues of TCA induced group whereas the ancillary enzyme GR and the drug metabolizing enzyme GST activity did not significantly change in the all tissues. The observations presented led us to conclude that the administration of subchronic TCA promotes lipid peroxidation content, elevates tissue damage serum marker enzymes and fluctuates in the antioxidative systems in rats. Also the rats resisted to oxidative stress via antioxidant mechanism but the antioxidant mechanism could not prevent the increases in lipid peroxidation in rat’s tissues. These data, along with the determined changes suggest that TCA produced substantial systemic organ toxicity in the erythrocyte, liver, brain and kidney during the period of a 50-day subchronic exposure. [Copyright &y& Elsevier]

Abstract: Copper bioavailability in the tissues of goldfish and antioxidant defenses in the liver of fish were investigated in vivo following 40 days of exposure to different species of copper solutions at different concentrations. Copper seemed to be more concentrated in the gill than in the liver after Cu2+ and copper-ethylenediaminetetraacetate (Cu–EDTA) exposure. The addition of EDTA markedly affected copper adsorption in the gill but had no significant effects in the liver. We also found that in the fish exposed to the concentration of Cu2+ below the Chinese national fishery water quality standard of 0.01mg/L, superoxide dismutase (SOD) and glutathione S-transferase (GST) activities in liver were stimulated and catalase (CAT) and Se-dependent glutathione peroxidase (Se-GPx) activities were inhibited after 40 days of exposure. Compared to copper exposure, the addition of EDTA did not affect SOD and GST significantly. However, CAT and GPx activity with Cu2+ exposure were significantly different from those with Cu–EDTA exposure. [Copyright &y& Elsevier]

Abstract: This study describes the subacute and subchronic effects of two plant growth regulators (PGRs) [abcisic acid (ABA) and gibberellic acid (GA3)] on serum marker enzymes [aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine phosphokinase (CPK) and lactate dehydrogenase (LDH), γ-glutamil transpeptidase (GGT)], antioxidant defense systems [reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] and lipid peroxidation level (Malondialdehyde=MDA) in various tissues of rats. Rats (Sprague–Dawley albino) were exposed to 75ppm (parts per million) of ABA and GA3. Seventy-five parts per million of PGRs as drinking water was administered orally ad libitum for 25 and 50 days continuously. The PGRs treatments caused different effect on the serum marker enzymes, antioxidant defense systems and the content of MDA in comparison to those of control rats. Results show that ABA caused a significant decrease in serum LDH and CPK activity with both periods. Also, GA3 significantly decreased serum AST, CPK, and LDH activity with subacute and decreased serum ALT, CPK, LDH, and GGT treated with subchronic periods. The lipid peroxidation end product MDA significantly increased in the erythrocyte, liver, brain, and muscle of rats treated with both the period of GA3 without significantly change in the erythrocyte and muscle of rats treated with the subacute period of ABA. The GSH levels were significantly depleted in the erythrocyte and brain of rats treated with both the period of GA3 without any change in the erythrocyte, liver, brain, and muscle of rats treated with both the period of ABA. Also GSH levels in the muscle significantly depleted with the subchronic period of GA3. Antioxidant enzyme activities such as SOD significantly decreased in the erythrocyte, liver and brain tissues but increased in the muscle tissue of rats treated with both the periods of GA3. Meanwhile, SOD significantly decreased in liver and brain, and increased in muscle of rats treated with both the period of ABA. While CAT significantly decreased in the all tissues of rats treated with both the period of GA3, decreased in the liver and muscle of rats treated with both the periods of ABA too. On the other hand, the ancillary enzyme GPx and GR activity in the erythrocytes, liver, brain and muscle were either significantly depleted or not changed with two periods of PGRs. The drug metabolizing enzyme GST activity significantly decreased in the brain of rats treated with subacute period of PGRs but increased in the erythrocytes of rats treated with subacute period of GA3. As a conclusion, ABA and GA3 had significantly increased the activity of hepatic damage enzymes. Also the rats resisted to oxidative stress via antioxidant mechanism. However, the antioxidant mechanism could not prevent the increases in lipid peroxidation in rat’s tissues. These data, along with changes, suggest that PGRs produced substantial systemic organ toxicity in the erythrocyte, liver, brain, and muscle during the period of a 25-day subacute and 50-day subchronic exposure. [Copyright &y& Elsevier]

Abstract: This study aims to investigate the effects of indoleacetic acid (IAA) and kinetin (Kn), which are plant growth regulators (PGRs), on antioxidant defense systems [reduced glutathione (GSH), glutathione-S-transferase (GST), catalase (CAT)], and lipid peroxidation level (malondialdehyde, MDA) various tissues of rats. Rats (Sprague–Dawley albino) were exposed to 100ppm IAA and Kn. One hundred parts per million of PGRs was administered orally to rats ad libitum for 21days continuously. The PGRs treatments caused different effects on the content of MDA and antioxidant defense system in comparison to those of control rats. According to the results, the subchronic treatments of IAA caused significant decrease in the GSH concentration and CAT activity in erythrocyte. Kn decreased GSH concentration in erythrocyte too. While the MDA concentration in brain was increased significantly by IAA and Kn, Kn decreased significantly brain CAT and GST activity. The liver GST activity was decreased by IAA and Kn. But, liver CAT activity was increased by IAA. On the other hand, while IAA treatment caused a significant decrease kidney GST activity, Kn caused a significant decrease both kidney GST and CAT activity. Also, while heart CAT activity was decreased by IAA, heart GST activity was decreased by both IAA and Kn. Moreover, MDA concentration in heart was increased by Kn treatment. It was concluded that IAA might effect MDA and antioxidant defense on the animals at subchronic treatment. [Copyright &y& Elsevier]

Larval goldfish Carassius auratus were exposed to 0.05 and 0.1 mg/L No. 20 diesel oil, widely used as transportation power in China, for 2, 4, 7, 10, 15, 25, and 40 days, while one control group was designated for each exposure group. Some fish after 25 days of exposure were transferred to diluted water until the 40th day. Hepatic antioxidant defense parameters of fish, including contents of reduced glutathione and glutathione disulfide and activities of superoxide dismutase, catalase, glutathione reductase, selenium-dependent glutathione peroxidase, and glutathione S-transferase, were determined and compared to control values. All the results indicated that the antioxidant responses of the fish to the two concentrations of oil exposure were similar on the whole. The possible defense mechanisms of fish and prospective early biomarkers for the evaluation of an oil-dominant contaminated aquatic ecosystem are discussed. In addition, after fish were removed from oil exposure, the recovery status of these antioxidant indices was explored. [Copyright &y& Elsevier]

The effect of lactic acid stress on the physiology and antioxidant activity of Pediococcus pentosaceus R1 and Lactobacillus fermentum R6 was investigated in this study. Both the strains were incubated in de Man, Rogosa, and Sharpe (MRS) broth with different pH values (6.0, 5.5, 5.0, 4.5, 4.0, and 3.5) at 37 °C for 1 h. The results revealed that the survival rates of both the strains significantly decreased with a decrease in pH from 4.5 to 3.5 (P < 0.05). Reactive oxygen species levels increased, while ATP concentrations decreased. Moreover, transmission electron microscopy analysis revealed severe cell damage with a decrease in pH. However, the hydrogen peroxide tolerance, free radical scavenging rates, reducing power, superoxide dismutase and glutathione peroxide activities, and total antioxidant capacities of both the strains were improved with a decrease in pH from 5.0 to 4.0, which indicated that appropriate lactic acid stress can improve the antioxidant activities of both the strains. This study brings a new strategy for improving the antioxidant activities of lactic acid bacteria and provides valuable information on the application of these strains as antioxidant starter cultures in fermented foods. • ATP concentrations of P. pentosaceus and L. fermentum decreased with lactic acid stress. • ROS levels of the two strains increased with lactic acid stress. • Both the strains had higher antioxidant potential when the pH was not lower than 4.0. • Antioxidant enzyme activities of both the strains increased with acid stress. [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNTs) have recently attracted huge attention to their impacts on the environment and plants. Therefore, this experiment was conducted to investigate the responses of lead (Pb) and cadmium (Cd) exposed pot marigold plants to various levels of MWCNT. Calendula officinalis (L.) seedlings were cultivated in Pb and Cd-polluted soils with exposure to 0, 50, 100, 250, 500 and 1000 mg L−1 of MWCNT. The results demonstrated that foliar-applied MWCNT up to 250 mg L−1 not only alleviated Pb and Cd-induced toxicity by reducing oxidative damage and boosting both enzymatic and non-enzymatic antioxidant defense system but also promoted the phytoremediation property of pot marigold plants by enhancing the accumulation of both Pb and Cd from the soil. Interestingly, oxidative damage exacerbation and both Pb and Cd accumulation reduction were noticed in pot marigold seedlings exposed to 500 and 1000 mg L−1 MWCNTs. The findings of this study clearly showed that the use of appropriate concentrations of MWCNTs in increasing the phytoremediation properties of pot marigold was justified, while the use of high concentrations is toxic to the plant and intensifies the toxic effects of heavy metals (HMs) on plant physiology. This study provides a novel method to facilitate the phytoremediation of HMs polluted soils using MWCNT as well as explores the potential risks of these nanoparticles to the plants. • The foliar-application of MWCNT alleviated Pb and Cd-induced toxicity. • MWCNTs reduced oxidative damage and boosted antioxidant defense system. • The lower doses of MWCNTs could be used for increasing phytoremediation properties to Calendula officinalis (L.). [ABSTRACT FROM AUTHOR]

The flavonoid metal-insecticide [Mg(hesp) 2 (phen)], denominated MgHP, has high potential for controlling agricultural pests. If applied in large scale, it may reach aquatic ecosystems and be harmful to the biota. This study evaluated the effects of MgHP in the gills of the Neotropical fish, Prochilodus lineatus by determining the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione s-transferase (GST), and the levels of glutathione (GSH) and lipid peroxidation (LPO) after 24 and 96 h exposure to 0, 1, 10, 100 and 1000 μg L−1. The histopathological changes with emphases to mitochondria-rich cells (MRC) were evaluated as well. After 24 h exposure the enzyme activities and the GSH and LPO levels were unchanged however, after 96 h exposure to high MgHP concentration (1000 μg L−1), the GST activity and GSH levels increased. Oxidative stress measured as LPO levels did not occur after MgHP exposure in both periods. Gill tissue alterations increased after MgHP exposure to 10, 100 and 1000 μg L−1. Cellular atrophy, pillar cells changes, filament epithelium hyperplasia and hypertrophy, lamellar epithelium hyperplasia were the most frequent histopathology. MRC in the filament epithelium decreased after exposure to 24 h and increased after 96 h indicating possible transitory osmo-ionic disruption. P. lineatus exhibited high tolerance to MgHP. The increased GST activity and GSH levels after 96 h exposure suggested possible MgHP accumulation and concentration- and time-dependent response. Histopathology in the gills of exposed fish occurred at high MgHP concentrations. These results suggested that the MgHP into water, at high concentrations, affect the gills by changing GST activity, GSH levels and histology being useful biomarkers for MgHP water contamination. • The metal-insecticide [Mg(hesp) 2 (phen)], the MgHP, induces changes in fish gills. • Glutathione-S-transferase and glutathione increased after exposure (96 h) to MgHP. • Lipid peroxidation unchanged after 24 and 96 h exposure to MgHP. • Mitochondria-rich cells decreased and increased after 24 and 96 h MgHP exposure. • Gill histopathology exhibited time- and dose-dependence response to MgHP exposure. [ABSTRACT FROM AUTHOR]

This paper reports the role of exogenous glycine betaine (25 and 50 mM GB at a rate of 50 mL per plant) in enhancing NaCl-stress tolerance in common bean (Phaseolus vulgaris L.). Irrigating plants by simulated saline water, containing 0, 50 and 100 mM sodium chloride (NaCl), significantly reduced the growth dynamics, photosynthetic pigments (i.e., Chl a, Chl b, and carotenoids), membrane stability index (MSI), relative water content (RWC), and pod yield. While, malondialdehyde (MDA), endogenous proline, and glutathione contents, electrolyte leakage (EL), antioxidant defense system, and Na+ accumulation markedly increased upon exposure to NaCl-stress. However, the application of exogenous GB significantly improved salt tolerance of common bean as it increased the antioxidant defense including both enzymatic (i.e., peroxidase, superoxide dismutase, and catalase) and nonenzymatic (i.e., proline and glutathione) agents. Consequently, MSI, RWC, EL, and photosynthetic pigments have been improved recording significantly higher values than the control. Moreover, the pod yield increased by 29.8 and 59.4% when plants grown under 50 and 100 mM NaCl, respectively, were sprayed with 25 mM GB. Our results show that GB-induced slat tolerance in common bean plants mainly depends on the osmoregulation effect of GB and to a lesser extent on its antioxidant capacity. Foliar application of GB significantly reduced the accumulation of Na+ and at the same time induced K+ uptake maintaining a higher K+/Na+ ratio. Despite some changes in the activities of antioxidant enzymes induced by the application of GB, no consistent contribution in the salt tolerance could be cited in this study. Therefore, we suggest that salt tolerance is largely unrelated to the antioxidant defense ability of GB in common bean. While the potential role of GB in ameliorating salt tolerance is mainly due to the adjustment of ions uptake through limiting Na+ uptake and alternatively increasing K+ accumulation in plant tissues. • NaCl stress adversely affects the growth and development of common bean. • NaCl stress reduces RWC, MSI, photosynthetic pigments, and yield. • NaCl stress increased activity of CAT, POD, and SOD and proline and glutathione content. • Foliar application of glycine betaine induces salt tolerance through osmoregulation and antioxidant defense properties. • Glycine betaine mainly limits Na+ uptake and alternatively increases K+ accumulation. [ABSTRACT FROM AUTHOR]

Nano-titanium dioxide (nTiO 2) has been reported to improve tolerance of plants against different environmental stresses by modulating various physiological and biochemical processes. Nitric oxide (NO) has been shown to act as an important stress signaling molecule during plant responses to abiotic stresses. The present work was planned to investigate the involvement of endogenous NO in nTiO 2 -induced activation of defense system of fava bean (Vicia faba L.) plants under water-deficit stress (WDS) conditions. Water-suffered plants showed increased concentration of hydrogen peroxide (H 2 O 2) and superoxide (O 2 −) content coupled with increased electrolyte leakage and lipid peroxidation which adversely affected nitrate reductase (NR) activity, chlorophyll content and growth of the plants. However, application of 15 mg L−1 nTiO 2 to stressed plants significantly induced NR activity and synthesis of NO which elevated enzymatic and non-enzymatic defense system of the stressed plants and suppressed the generation of H 2 O 2 and O 2 − content, leakage of electrolytes, and lipid peroxidation. Application of nTiO 2 , in association with NO, also enhanced the accumulation of osmolytes (proline and glycine betaine) that assisted the stressed plants in osmotic adjustment as witnessed by improved hydration level of the plants. Involvement of NO in nTiO 2 -induced activation of defense system was confirmed with NO scavenger cPTIO [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide] which caused recurrence of WDS. Image 1 • Water-deficit stress (WDS) causes severe damage to crops worldwide. • Nano-titanium dioxide (nTiO 2) protects the plants against WDS. • nTiO 2 counters WDS-induced oxidative and osmotic stress. • nTiO 2 induces antioxidant defense system and osmolytes accumulation. • nTiO 2 involves endogenous nitric oxide in the activation of plant's defense system. [ABSTRACT FROM AUTHOR]

Iron in excess can have toxic effects on living organisms. In China, the freshwater crayfish Procambarus clarkii is a source of aquatic food with high-quality protein and has significant commercial value. P. clarkii shows oxidative stress on exposure to heavy metals, and antioxidant enzymes, such as ubiquitination enzymes and proteasomes, play important roles in oxidative stress. To understand the antioxidant defense system of P. clarkii , we analyzed the hepatopancreas transcriptomes of P. clarkii after stimulation with FeCl 3. In total, 5199 differentially expressed genes (DEGs) were identified (2747 upregulated and 2452 downregulated). GO analysis revealed that these DEGs belonged to 16 cellular component, 16 molecular function, and 19 biological process subcategories. A total of 1069 DEGs were classified into 25 categories by using COG. Some antioxidant defense pathways, such as "Ubiquitin mediated proteolysis" and "Glutathione metabolism," were identified using KEGG. In addition, quantitative real time-PCR (qRT-PCR) substantiate d the up-regulation of a random selection of DEGs including antioxidant and immune defense genes. We obtained information for P. clarkii transcriptome databases and new insights into the responses of P. clarkii hepatopancreas to heavy metals. • The hepatopancreas transcriptomes of Procambarus clarkii were constructed using high-throughput sequencing. • The expressions of antioxidant and immune defense genes were induced in response to Fe (III) stress. • Totally 30,438 unigenes was obtained from the transcriptome. • Totally 5199 DGEs were identified including 2747 up- and 2452 down-regulated unigenes. [ABSTRACT FROM AUTHOR]