Application of Polygonum minus Extract in Enhancing Drought Tolerance in Maize by Regulating Osmotic and Antioxidant System

Drought stress is a major factor affecting plant growth and crop yield production.Plant extracts as natural biostimulants hold great potential to strengthen plants to overcome drought impacts.To explore the effect of Polygonum minus extract(PME)in enhancing drought tolerance in plants,a study was set up in a glasshouse environment using 10 different treatment combinations.PME foliar application were designed in CRD and effects were closely observed related to the growth,physiology,and antioxidant system changes in maize(Zea mays L.)under well-watered and drought conditions.The seaweed extract(SWE)was used as a comparison.Plants subjected to drought stress exhibited a significant reduction in fresh weight,dry weight,relative water content(RWC),and soluble sugar,but they stimulated the phenolic,flavonoid,proline,glutathione(GSH),malondialdehyde(MDA)and antioxidant enzyme(catalase,CAT;peroxidase,POD;superoxide dismutase,SOD)activities.Foliar application of PME improved fresh and dry weight(FW:33.1%~41.4%;DW:48.0%~43.1%),chlorophyll content(Chl b:87.9%~100.76%),soluble sugar(23.6%~49.3%),and soluble protein(48.6%~56.9%)as well as antioxidant enzyme activities(CAT and POD)compared to CK under drought conditions.while decreasing the level of MDA.Notably,the mitigating effect of PME application with high concentration was more effective than those of SWE.Our study reveals that PME could alleviate drought stress by regulating osmoprotectant content and antioxidant defense system and can be used as an economical and environmentally friendly biostimulants for promoting maize growth under drought stress.

Ellagic Acid Enhances Antioxidant System Activity and Maintains the Quality of Strawberry Fruit during Storage

Ellagic acid(EA)is a natural antioxidant,widely present in a lot of forms’soft fruits,nuts,and other plant tissues,and helpful for promoting human health;however,its protective effect on postharvest fruit and improving the quality index of postharvest fruit have rarely been studied.In this experiment,the strawberries were soaked in 0,100,200,300,400,and 500 mg L^(−1) EA,respectively,and the influential EA on fruit quality and the antioxidant system of strawberries were studied.Compared with the control,EA treatment can reduce the browning degree and rotting rate of strawberry fruit during storage and augment the soluble solid content(SSC).EA treatment can also increase the content of related stuff and enzyme activity in antioxidant systems;the gene expression level of polyphenol oxidase(PPO)in strawberries treated with EA was always down-regulated,correspondingly,the expression of other antioxidant enzyme genes was enhanced.Among the strawberry fruits treated with EA of different concentrations,300 mg L^(−1) EA had the best effect in the process of strawberry preservation.The results suggested that the proper concentration of exogenous EA at 300 mg L−1 could maintain strawberries’quality and enhance the antioxidant system by improving the activities of antioxidative enzymes and the ascorbateglutathione(AsA-GSH)cycle during storage.

Effects of Manganese on the Antioxidant System and Related Gene Expression Levels in the “Hong Yang” Kiwifruit Seedlings

To explore how manganese affects the antioxidant system and the expression levels of related genes of“Hong yang”seedlings,the leaves of its tissue cultured seedlings were taken as test materials,and single factor treatment was performed by changing the manganese chloride(MnCl_(2)·4H_(2)O)solution concentration when spraying the leaves.The expression levels of Mn-SOD,POD64 and POD27 genes in leaves were quantitatively analyzed by real-time quantitative PCR(qRT-PCR)at different determination times.Meanwhile,the contents of malondial-dehyde(MDA),hydrogen peroxide(H_(2)O_(2)),the activities of antioxidant enzymes,including catalase(CAT),peroxidase(POD),and superoxide dismutase(SOD).The results showed that the SOD,CAT,POD,ascorbate peroxidase(APX),and reduced glutathione(GSH)activities in leaves were the highest at 12 h post-treatment with 50μM MnCl_(2)·4H_(2)O.Furthermore,the contents of MDA and H_(2)O_(2) in leaves also peaked when the concentration of H_(2)O_(2) is 50μM,which is the minimum value.Additionally at 50μM Mn^(2+),the Mn-SOD and POD27 expression was up-regulated as compared to the control,which promoted the expression of their respective enzyme activities.However,POD64 expression increased with the increasing Mn^(2+) concentration.Therefore,50μM is the optimal concentration of Mn when exogenously applied on“Hong yang”,which improve the antioxidant enzyme activity and regulate the plant’s physiological and biochemical functions.

Transcriptomes of Litopenaeus vannamei reveal modulation of antioxidant system induced by dietary archaeal carotenoids

Oxidative stress induced by factors such as ammonia nitrogen has become a major issue in shrimp farming.The effects of carotenoids on the growth and antioxidant capability of Litopenaeus vannamei juveniles were investigated in this study using dietary archaeal carotenoids supplementation.For four weeks,shrimp were given diets containing 0 mg/kg(Ctrl)and 55.98 mg/kg(Car)archaeal carotenoids.Dietary archaeal carotenoids significantly enhanced the astaxanthin content in shrimp muscles and carapaces,as well as the superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)activity(P<0.05).The malonaldehyde(MDA)content in Car group significantly decreased(P<0.05).The transcriptome analysis was conducted to determine the molecular processes in response to archaeal carotenoids supplementation.A total of 1536 differentially expressed genes(DEGs)were detected,including 538 upregulated DEGs and 998 downregulated DEGs.GO functional enrichment analysis between Ctrl and Car indicated that 26 GO terms including extracellular region,metabolic process,and proteolysis were enriched.The KEGG pathway enrichment analysis revealed that the amino sugar and nucleotide sugar metabolism,cysteine and methionine metabolism,glycine serine and threonine metabolism,and amino acid biosynthesis were enriched.Archaeal carotenoids influenced the expression of several important genes involved in reactive oxygen species(ROS)generation,Nrf2 signaling,and antioxidant enzymes.Seven DEGs were chosen to confirm the RNA-Seq data using qRT-PCR.The genes and pathways discovered in this work assist to elucidate the molecular processes through which archaeal carotenoid enhances L.vannamei antioxidative system.

Four-Octyl itaconate ameliorates periodontal destruction via Nrf2-dependent antioxidant system

Periodontitis is a widespread oral disease characterized by continuous inflammation of the periodontal tissue and an irreversible alveolar bone loss, which eventually leads to tooth loss. Four-octyl itaconate(4-OI) is a cell-permeable itaconate derivative and has been recognized as a promising therapeutic target for the treatment of inflammatory diseases. Here, we explored, for the first time,the protective effect of 4-OI on inhibiting periodontal destruction, ameliorating local inflammation, and the underlying mechanism in periodontitis. Here we showed that 4-OI treatment ameliorates inflammation induced by lipopolysaccharide in the periodontal microenvironment. 4-OI can also significantly alleviate inflammation and alveolar bone loss via Nrf2 activation as observed on samples from experimental periodontitis in the C57BL/6 mice. This was further confirmed as silencing Nrf2 blocked the antioxidant effect of 4-OI by downregulating the expression of downstream antioxidant enzymes. Additionally, molecular docking simulation indicated the possible mechanism under Nrf2 activation. Also, in Nrf2-/-mice, 4-OI treatment did not protect against alveolar bone dysfunction due to induced periodontitis, which underlined the importance of the Nrf2 in 4-OI mediated periodontitis treatment.Our results indicated that 4-OI attenuates inflammation and oxidative stress via disassociation of KEAP1-Nrf2 and activation of Nrf2 signaling cascade. Taken together, local administration of 4-OI offers clinical potential to inhibit periodontal destruction,ameliorate local inflammation for more predictable periodontitis.

The role of antioxidant system in freezing acclimation-induced freezing resistance of Populus suaveolens cuttings

We investigated the changes in the contents of H202, malonaldehyde （MDA） and endogenous antioxidants, the activities of protective enzymes and some critical enzymes involved in the ascorbate-glutathione （ASA-GSH） cycle as well as freezing resistance （expressed as LT50） and correlations mentioned above, in detail using Populus suaveolens cuttings. The purpose was to explore the physiological mechanism of the enhancement of freezing resistance induced by freezing acclimation at -20℃, and to elucidate the physiological mechanisms by which trees adapt to freezing. The results showed that freezing acclimation enhanced the activities of superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT）, monodehydroascorbate reductase （MDAR）, ascorbate peroxidase （APX）, dehydroascorbate reductase （DHAR） and glutathione reductase （GR）. And it increased the contents of reduced ascorbate （ASA）, reduced glutathione （GSH）, dehydroascorbate （DHA） and oxidized glutathione （GSSG）. However, H202 and MDA contents and LT50 of cuttings were decreased. LTs0 in cuttings was found to be closely correlated to the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, H202, MDA, ASA, GSH, DHA and GSSG during freezing acclimation. This suggested that the enhancement of freezing resistance of cuttings induced by freezing acclimation may relate to the distinct increase for the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, ASA, GSH, DHA, and GSSG. In addition, the observed levels of APX, DHAR, MDAR, GR, ASA, DHA, GSH and GSSG were higher than those of SOD, POD and CAT during freezing acclimation. It indicated that a higher capacity of the ASA-GSH cycle is required for H202 detoxification, and growth and development of cuttings. Based on the obtained results, it can be concluded that the ASA-GSH cycle plays an important role in enhancement of freezing resistance of P. suaveolens cuttings during freezing acclimation.

Effects of Hydrogen on Storage Decay and Antioxidant System of Strawberry

In order to determine whether hydrogen acts as antioxidant in plant tissues,fresh strawberry was put in sealed bags filled with 4%H_(2) atmosphere(T_(1)),100%H_(2)(T_(2)),100%air(CK_(1))and 100%N_(2)(CK_(2)),respectively.The decay rate,soluble solids content(SSC),titration acid(TA),ascorbic acid(Vc),MDA content,SOD and antioxidant activity in strawberry were measured during storage periods.Results showed that the decay rate and MDA content were reduced in H_(2) treatments;and H_(2) treatments gave lower level of TA and higher SSC,Vc,SOD and antioxidant activity,and 100%H_(2) had the best effect.It is suggested that strawberry fruit quality,antioxidant system and membrane lipid peroxidation were affected by H_(2) treatments.

Effect of methoxychlor on antioxidant system of goat epididymal sperm in vitro

Aim: To evaluate the effect of methoxychlor on the antioxidant system of goat epididymal sperm. Methods:Epididymis of adult goat was obtained from local slaughter houses and sperm were collected by chopping the epididymisin modified Ringer's phosphate solution (RPS). After several washings, the sperm samples were dispersed in RPS andincubated with methoxychlor (1μmol/L, 10μmol/L and 100μmol/L) and methoxychlor + vitamin C (100μmol/Leach) for 3 h at 32℃. After incubation, the sperm motility and viability were assessed. An aliquot of sperm samplewas homogenized, centrifuged and used for the assay of superoxide dismutase, glutathione peroxidase, glutathione re-ductase and lipid peroxidation. Results; In methoxychlor-incubated sperm and in sperm co-incubated with methoxy-chlor and vitamin C, the sperm motility and viability showed no significant changes as compared to the correspondingcontrols. In methoxychlor-incubated sperm the activity of superoxide dismutase, glutathione reductase and glutathioneperoxidase were decreased while lipid peroxidation was increased in a dose-dependent manner. Co-incubation of spermwith methoxychlor and vitamin C showed no changes in the activity of superoxide dismutase, glutathione reductase andglutathione peroxidase and in the level of lipid peroxidation. Conclusion; Methoxychlor induced oxidative stress inepididymal sperm of goats by decreasing the levels of antioxidant enzymes. Co-incubation of sperm with methoxychlorand vitamin C, a natural antioxidant, reversed the effect of methoxychlor. (Asian J Androl 2001 Dec; 3; 285 - 288)

Effect of lindane on testicular antioxidant system and steroidogenic enzymes in adult rats

Aim: To find out the effect of lindane on testicular antioxidant system and testicular steroidogenesis in adult malerats. Methods: Adult male rats were orally administered with lindane at a dose of 5.0 mg/kg body weight per dayfor 30 days. Twenty-four hours after the last treatment the rats were killed using anesthetic ether. Testes, epididymis,seminal vesicles and ventral prostate were removed and weighed. A 10% testicular homogenate was prepared and cen-trifuged at 4℃. The supernatant was used for various biochemical estimations. Results; The body weight and theweights of testes, epididymis, seminal vesicles and ventral prostate were reduced in lindane-treated rats. There was asignificant decline in the activities of antioxidant enzymes superoxide dismutase (SOD), catalase and glutathione reduc-tase while an increase in hydrogen peroxide (H_2O_2) generation was observed. The specific activities of testicularsteroidogenic enzymes 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase were decreased. Thelevels of DNA, RNA and protein were also decreased in lindane-treated rats. Conclusion: Lindane induces oxida-tive stress and decreases antioxidant enzymes in adult male rats.

Effects of 24-Epibrassinolide on Antioxidant System in Cucumber Seedling Roots Under Hypoxia Stress

This article aims to study the effects of exogenous 24-epibrassinolide （EBR） on the changes in ROS, activities of antioxidative enzymes and antioxidants in cucumber （Cucumis sativus L.） seedling roots under hypoxia stress. Seedlings of a hypoxiaresistant cultivar, Lühachun 4, and a hypoxia-sensitive cultivar, Zhongnong 8, were hydroponically grown for 8 d in normoxic or hypoxic nutrient solutions that were added or not added with 10^-3 mg L^-1 EBR. Under hypoxia stress, the ROS levels and the lipid peroxidation were significantly increased in the roots upon exposure to hypoxia stress, which were inhibited by EBR application. The EBR treatment significantly increased the seedlings growth and SOD, APX, GR activities, and contents of AsA and GSH under hypoxia stress. From the results obtained in this study, it can be concluded that oxidative damage on seedling roots by hypoxia stress can be considerably alleviated and the tolerance of plants was elevated.

Responses of the antioxidant system to fluroxypyr in foxtail millet (Setaria italica L.) at the seedling stage

Foxtail millet （Setaria italica L.） is an important food and fodder crop in semi-arid areas. However, there are few herbicides suitable for use on weed control in field-grown foxtail millet during the post-emergence herbicides stage. The present study was conducted using four concentrations （0.5, 1, 2, and 4 L ai ha-1） of foliar-applied fluroxypyr, and the effect of fluroxypyr on selected metabolic and stress-related parameters in foxtail millet were assessed after 15 days. In this study, increasing concentrations decreased plant height and accumulation of chlorophylls. Our results also showed that malondialdehyde （MDA） accumulated in response to fluroxypyr application, demonstrating increased lipid peroxidation due to excessive reactive oxygen species production. In response to this oxidative stress, the activities of antioxidant enzymes were generally enhanced. Non-enzymatic antioxidant defense systems, which function in concert with antioxidant enzymes, can also protect plant cells from oxidative damage by scavenging reactive oxygen species （ROS）. In conclusion, the hybrid variety （Zhangzagu） exhibited a greater tolerance to fluroxypyr than did the conventional variety Jingu 21, which might be associated with the antioxidant mechanisms of Zhangzagu hybrid millet.

Impact of poly chlorinated biphenyl (Aroclor 1254) and vitamin C on antioxidant system of rat ventral prostate

Aim: To evaluate the effect of polychlorinated biphenyls (PCB) and vitamin C on ventral prostatic antioxidant system in adult male rats. Methods: A group of 20 adult male rats were administered ip Aroclor 1254 in corn oil at a dose of 2 mg·kg-1·day-1 for 30 days. Ten control rats were administered only the vehicle. After 30 days the treated rats were divided at random into 2 sub-groups of 10 animals each. One sub-group received vitamin C at a dose of 500 mg·kg-1·day-1 for 10 days. The other group was maintained as Aroclor 1254 control. Twenty-four hours after the last treatment the rats were killed by decapitation. Ventral prostatic homogenate was prepared and used for the estimation of enzymatic antioxidants, including superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) and hydrogen peroxide (H2O2), lipid peroxidation (LPO) and prostatic acid phosphatase. The serum levels of total T3, total T4, TSH, testosterone and estradiol were also assayed. Results: The body weight and ventral prostatic weight were reduced in PCB treated rats. The activities of SOD, CAT, GST and acid phosphatase were decreased while the levels of H2O2 and lipid peroxidation were increased in the ventral prostate of PCB treated rats. Administration of vitamin C restored these parameters. Serum levels of thyroid hormones, estradiol and testosterone were decreased in PCB treated animals. Administration of vitamin C restored the thyroid hormone levels. Conclusion: PCB induces oxidative stress and decreases the antioxidant enzymes in the ventral prostate of adult male rats; the effects could be reversed by the administration of vitamin C.

Enzymatic antioxidant system in vascular inflammation and coronary artery disease

In biological systems there is a balance between the production and neutralization of reactive oxygen species(ROS). This balance is maintained by the presence of natural antioxidants and antioxidant enzymes suchas superoxide dismutase(SOD), catalase and glutathione peroxidase. The enhancement of lipid peroxidation or the decrease of antioxidant protection present in metabolic diseases or bad lifestyle can induce endothelial dysfunction and atherosclerosis.Clinical studies have shown that oxidative stress can increase ROS reducing the formation of antioxidant defences, especially in subjects with coronary artery disease(CAD). Some observation indicated that in the early stages of the disease there is a homeostatic upregulation of the antioxidant enzyme system in response to increased free radicals to prevent vascular damage.As soon as free radicals get to chronically elevated levels, this compensation ceases. Therefore, SOD and the other enzymes may represent a good therapeutic target against ROS, but they are not useful markers for the diagnosis of CAD. In conclusion antioxidant enzymes are reduced in presence of metabolic disease and CAD. However the existence of genes that promote their enzymatic activity could contribute to create new drugs for the treatment of damage caused by metabolic diseases or lifestyle that increases the plasma ROS levels.

Antioxidant systems of aquatic macrophytes in three life forms:a case study in Lake Erhai,China

Antioxidant systems are vital in life activities of macrophytes. Species with diff erent life forms need to cope with distinct environments by modifying physiological characters, especially antioxidant systems. In order to find diff erences among life forms and consequence of lake eutrophication, we studied three antioxidant enzymes activity (superoxide dismutase (SOD), ascorbate oxidase (APX) and catalase (CAT)) and total soluble phenolics (TP) content in leaves of 26 macrophyte species in September 2013 in Lake Erhai, China. We found that antioxidation varied accordingly with life forms. The activities of SOD and APX in emergent macrophytes (EM) and floating-leaved macrophytes (FM) were much lower than those of submerged macrophytes (SM). On the contrary, TP content was much higher in EM and FM species. There was a negative correlation between TP and antioxidant enzyme activities (CAT and APX). The results suggested that EM and FM species rely on phenolics might to adapt to adverse environments (higher herbivores predation pressure and UV radiation intensity), while SM species more rely on antioxidant enzymes possibly due to lower demand for antioxidation and/or lack of light and inorganic C availability for phenolics synthesis. We also found FM species represent highest fitness in term of antioxidant system, which would lead to overgrowth of FM species and littoral zone bogginess during lake eutrophication. Finally, it is necessary to carry out the verification experiment under the control condition in the later stage, especially for the dominant ones in eutrophic lakes, to understand the exact adaptive mechanisms of them.

Isoflavone Ameliorates H₂O₂Induced Injury by Activating the Antioxidant System of Sow Mammary Gland Cell

The antioxidant and protective properties of a synthetic soybean isoflavone (ISO) were investigated using sow mammary gland cell. Cells were cultured with 10, 20 and 30 uM ISO, respectively, under 80 uM FeSO4·7H2O/H2O2 conditions. After 48 h of incubation, the cells in the presence of ISO were lost less compared with that of control under oxidative damage by H2O2/FeSO4;ISO decreased the cell number at G1 and G2 stages, increased the cell number at S stage (all P < 0.05), it also reduced apoptosis of the cells (P P P < 0.05). The addition of ISO significantly promoted cell proliferation (P rd to 6th days. Upon these, the activities of total superoxide dismutase (SOD), glutathione peroxidase (GPX), total antioxidant ability (T-AOC) also were increased and the activities of NADPH oxidase (NOX) decreased by ISO treatment (all P < 0.05). ISO decreased the concentration of ROS (P P < 0.05). 10 uM, 20 uM, 30 uM ISO increased the relative mRNA abundance of SOD1 (all P P P P < 0.05) and SOD3 (all P < 0.05);ISO significantly increased the relative mRNA abundance of GPX4 (all P P < 0.05), 20 uM ISO also increased the relative mRNA abundance of NOX2 (P < 0.05). It was concluded that supplementation of ISO enhanced the anti-oxidative function and prevented lipid peroxidation, possibly through the activation of the antioxidant enzymes and inhibition of cell apoptosis.

Effects of broccoli extract and various essential oils on intestinal and faecal microflora and on xenobiotic enzymes and the antioxidant system of piglets

Objective: Since the ban of antibiotics as growth promoting feed additives in the EU in 2006 research in alternatives has gained importance. Phytogenic feed additives represent a heterogenous class of different plant derived substances that are discussed to improve the health of farm animals by direct and indirect antioxidant effects and by influencing microbial eubiosis in the gastrointestinal tract. Consequently our study aimed to investigate the influence of broccoli extract and the essential oils of tur- meric, oregano, thyme and rosemary, as selected individual additives, on intestinal and faecal microflora, on xenobiotic enzymes, and on the antioxidant system of piglets. Methods: 48 four weeks old male weaned piglets were assigned to 6 groups of 8. The piglets were housed individually in stainless steel pens with slatted floor. The control group (Con) was fed a diet without an additive for 4 weeks. The diet of group BE contained 0.15 g/kg sulforaphane in form of a broccoli extract. 535, 282, 373 and 476 mg/kg of the essential oils of turmeric (Cuo), oregano (Oo), thyme (To) and rosemary (Ro) were added to the diets of the remaining 4 groups to stan-dardise supplementation to 150 mg/kg of the oils’ key terpene compounds ar-turmerone, carvacrol, thymol and 1,8-cineole. The composition of bacterial microflora was examined by cultivating samples of jejeunal and colonic mucosa and of faeces under specific conditions. The mRNA expression of xenobiotic and antioxidant enzymes was determined by reversing transcrip- tase real time detection PCR (RT-PCR). Total antioxidant status was assayed using the Trolox Equivalent Antioxidant Capacity (TEAC), and lipid peroxidation was determined by measuring thiobarbioturic acid reactive substances (TBA- RS). Results: Compared to Con piglets all additives positively influenced weight gain and feed conversion in week 1. Over the whole trial period no significant differences in performance parameters existed between the experimental groups. Compared to group Con performance of Ro piglets was, however, slightly impaired. Com- pared to Con piglets Cuo, Oo and To increased the ratio of Lactobacilli:E. coli attached to the jejunal mucosa, whereas BE and Ro impaired this ratio slightly. In contrast in colonic mucosa Ro improved Lactobacilli:E. coli ratio. In faecal samples an improvement of Lactobacilli:E. coli ratio could be analysed for To and Ro. Ro was the only additive that reduced the incidence rate of piglets tested positive for enterotoxic E. coli (ETEC). All additives significantly increased jejunal TEAC and reduced TBA-RS. In the liver BE, Cuo, Oo and To increased TEAC in tendency and Ro significantly. Liver TBA-RS were slightly reduced by all additives compared to Con piglets. Whereas the influence of BE, To and Ro on jejunal TEAC mainly was derived from the induction of xenobiotic and antioxidant enzymes (indirect antioxidant effects), Cuo and Oo influenced TEAC by direct antioxidant effects. Discussion and Conclusions: Our results have shown: That within the labiatae oils Oo and To have the potential to improve performance slightly. That phytogenic substances have a small but not sig- nificant influence on intestinal microflora. That phytogenic feed additives up-regulate the anti- oxidant system of piglets either by direct or by indirect antioxidant effects and that they may thereby improve health status. That within the labiatae oils Oo has a high direct antioxidant potential whereas Ro potently induces xenobiotic and antioxidant enzymes. That broccoli extract is an attractive new phytogenic additive, improving antioxidant status by indirect antioxidant effects. That defined combinations of selected phytogenic substances may produce additive effects. That health promoting effects of phytogenic additives in the future should be studied systematically under the challenge with pathogenic microorganisms or food derived to-xins.

Using the TEOST^(■) MHT-4 to Identify Robust Antioxidant Systems for Modern Engine Oils

A research tool has been developed that utilizes the Thermo-Oxidation Engine Oil Simulation Test (TEOST) MHT-4 to collect information on engine oil oxidation and deposit formation. The technique capitalizes on the traditional TEOST features as a deposit formation test, but also generates additional oxidation information by monitoring peak increase in the carbonyl region of the Fourier Transform Infrared Spectrum (FT-IR) of TEOST used oils and volatiles. The data on overall oxidation and deposit formation is used to generate a "robustness" model for modern engine oil degradation. The tool is used to study low phosphorus Group Ⅱ passenger car engine oils formulated with different types of antioxidants and a molybdenum dithiocarbamate (MoDTC). The model shows that improved oxidation and deposit control can be achieved by formulating with the molybdenum compound, and that the most effective stabilization system is composed of the organo-molybdenum compound,an alkylated diphenylamine (NDPA), and the hindered phenolic antioxidant 4,4′-methylenebis(2,6-di-tert-butylphenol) (MBDTBP).

Ameliorative effect of zinc oxide and silver nanoparticles on antioxidant system in the brain of diabetic rats

Objective: To test the ability of both zinc oxide nanoparticles(Zn ONPs) and silver nanoparticles(SNPs) to ameliorate the oxidative stress resulted from diabetes in diabetic rats.Methods: Fifty male albino rats were used; ten of them were served as control group and forty, as the experiment group, were injected with streptozotocin at the single intraperitoneal dose of 100 mg/kg. Then, the experiment group was subdivided into, diabetic,diabetic + Zn ONPs, diabetic + SNPs and diabetic + insulin groups. The activities and m RNA expression levels of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase were determined in brain tissues. Malondialdehyde, total antioxidant capacity, zinc and silver concentrations were estimated in the brain tissues of all rats.Results: A significant increase in the activities and m RNA expression levels of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase was shown.Malondialdehyde levels were significantly decreased while there was a significant increase in the zinc, silver concentrations and total antioxidant capacity in brain of Zn ONPs and SNPs treated rats, compared with diabetic or diabetic + insulin group and their control group.Conclusions: Zn ONPs and SNPs can be used to ameliorate the oxidative stress in brain resulted from diabetes mellitus.

Wheat Straw Burial Improves Physiological Traits, Yield and Grain Quality of Rice by Regulating Antioxidant System and Nitrogen Assimilation Enzymes under Alternate Wetting and Drying Irrigation

Wheat straw burial has great potential to sustain rice production under alternate wetting and drying(AWD)irrigation.A field experiment was conducted with three wheat straw burial treatments,including without straw burial(NSB),with light straw burial of 300 kg/hm^(2)(LSB)and dense straw burial of 800 kg/hm^(2)(DSB),as well as three AWD regimes:alternate wetting/moderate drying(AWMD),alternate wetting/severe drying(AWSD)and alternate wetting/critical drying(AWCD).The rice growth and grain quality were higher in LSB and NSB than those in NSB under the same AWD regime.The AWMD×DSB treatment resulted in the highest yield,brown rice rate,milled rice rate,amylose content and protein content.Conversely,the AWCD×NSB treatment led to the lowest yield,brown rice rate,milled rice rate,amylose content and protein content.The active absorption area and nitrate reductase activity of roots were higher in the AWMD×DSB treatment than those in the AWCD×NSB treatment,as the former increased organic carbon and nitrogen contents in the rhizosphere,whereas the latter reduced their availability.Total soluble protein content and glutamine synthetase activity were greater in the AWMD×DSB treatment than those in the AWCD×NSB treatment.The activities of superoxide dismutase and catalase were higher in the AWMD×DSB treatment compared with the AWCD×NSB treatment,leading to the amelioration of oxidative cell injury,as shown by a lower malonaldehyde level.This study suggested that farmers should implement AWMD irrigation after leaving the straw residues in the field,followed by deep tillage to improve soil quality and mitigate the drought stress cycles of AWD.This approach can improve rice growth and grain quality and alleviate the problems of disposal of straw residues and water scarcity for sustainable rice production.

Melatonin Alleviates Abscisic Acid Deficiency Inhibition on Photosynthesis and Antioxidant Systems in Rice under Salt Stress

Melatonin and abscisic acid,as major plant hormones,play important roles in the physiological and biochemical activities of crops,but the interaction between the two under salt stress is not yet clear.This study investigated the endogenous levels of melatonin and abscisic acid in rice by using exogenous melatonin,abscisic acid,and their synthetic inhibitors,and examined their interactions under salt stress.The research results indicate that melatonin and abscisic acid can improve rice salt tolerance.Melatonin alleviated the salt sensitivity caused by abscisic acid deficiency,increased antioxidant enzyme activity and antioxidant content in rice treated with abscisic acid synth-esis inhibitors,and reduced total reactive oxygen species content and thiobarbituric acid reactive substance accu-mulation.Melatonin also increased the activity of key photosynthetic enzymes and the content of photosynthetic pigments,maintaining the parameters of photosynthetic gas exchange and chlorophyllfluorescence.In summary,melatonin alleviated the effects of abscisic acid deficiency on photosynthesis and antioxidant systems in rice and improved salt tolerance.This study is beneficial for expanding the understanding of melatonin regulation of crop salt tolerance.