Levels Of AsA Research Articles

DNP and ATP modulate the pulp softening and breakdown in fresh longan by acting on the antioxidant system and the metabolisms of membrane lipids and cell wall polysaccharides

Compared to the control longan, DNP treatment elevated pulp breakdown index, reduced the values of pulp firmness, CSP, ISP, cellulose, and hemicellulose by enhancing the activities of PE, PG, Cx, XET, and β-Gal. Additionally, DNP treatment increased the levels of PLD, lipase, LOX, PA, and SFA, and decreased the values of PC, PI, USFA, U/S, and IUFA, displaying higher cell membrane permeability and more severe cell membrane damage in longan pulp. Furthermore, DNP treatment weakened the levels of SOD, CAT, APX, AsA, GSH, TP, and TF, thereby exacerbating ROS outbreak and MDA production. These results indicate that DNP treatment destroyed the antioxidant system to cause ROS eruption. This disruption further disturbed the metabolisms of membrane lipids and cell wall polysaccharides, leading to the breakdown of cell membrane and cell wall, and eventually aggravated longan pulp softening and breakdown. However, ATP treatment exhibited the opposite effects of DNP treatment.

Acidic electrolyzed-oxidizing water treatment mitigated the disease progression in Phomopsis longanae Chi-infected longans by modulating ROS and membrane lipid metabolism

Postharvest harmful pathogenic infestation leads to rapid decay in longan fruit. Compared with P. longanae-infected longans, AEOW alleviated fruit disease severity and diminished the O2-. production rate and MDA content. It also increased APX, CAT, and SOD activities, delayed the decrease in the levels of GSH and AsA, as well as the reducing power and DPPH radical scavenging ability, which resulted in a decline in membrane lipid peroxidation in P. longanae-infected longans. Additionally, AEOW reduced LOX, lipase, PI-PLC, PC-PLC, and PLD activities, maintained higher levels of PC, PI, IUFA, USFAs, and U/S, while reducing levels of PA, DAG, SFAs, and CMP. These effects alleviated membrane lipid degradation and peroxidation in P. longanae-infected longans. Consequently, AEOW effectively maintained membrane integrity via improving antioxidant capacity and suppressing membrane lipid peroxidation. This comprehensive coordination of ROS and membrane lipid metabolisms improved fruit resistance and delayed disease development in longans.

Inhibitory impact of Chlorine dioxide on Potato tuber sprouting via inducing oxidative stress

This study aimed to investigate the performance of ClO2 in suppressing potato tuber sprouting and reveal the corresponding mechanism. During the storage period, we determined the sprout rate and index, monitored tissue structure and evaluated the active oxygen metabolism in the potato bud eyes. The results indicated that ClO2 inhibited the rate and index sprouting. After ClO2 treatment, the activities of key enzymes related to reactive oxygen species production in potato tubers significantly increased, resulting in the accumulation of O2•− and H2O2 in the bud eyes. O2•− and H2O2 was increased by 87.4 % and 65.0 % compared to the control, respectively. Furthermore, our results showed that the ClO2 treatment improved the cell membrane permeability, increased the malondialdehyde (MDA) content, and impaired the cell membrane integrity of potato bud eyes. The cell membrane permeability and MDA level of the ClO2-treated tubers were increased by 45.9 % and 30.2 %, respectively, in comparison to the control. Additionally, ClO2 increased the activities of antioxidative enzymes (CAT and POD) and decreased the activities of enzymes in the AsA-GSH cycle, as well as the levels of AsA and GSH, leading to cellular redox imbalances. We conclude that ClO2 can inhibit the sprouting of postharvest potatoes by modulating active oxygen metabolism.

Nanoselenium inhibits chromium toxicity in wheat plants by modifying the antioxidant defense system, ascorbate glutathione cycle, and glyoxalase system

Chromium (Cr) stress negatively impacts plant growth and physiological processes, making it a significant environmental concern. This study investigates the effectiveness of selenium nanoparticles (Se-NPs) in mitigating Cr stress on plants, comparing its efficacy with traditional selenium (Se). Nevertheless, research on using soil-applied Se-NP to lessen Cr buildup in plants has not been widely documented as of now. Here, we investigate the effectiveness of Se-NPs in mitigating Cr stress on plants, comparing their efficacy with traditional Se and control. Under the pervasive influence of Cr stress, Se-NPs exhibit remarkable superiority over conventional Se, significantly enhancing growth parameters (fresh weight, dry weight, shoot length, and root length), respectively, compared to the Cr-stressed plants. Physiologically, Se-NPs outperform Se by substantially improving the net photosynthesis rate (+32%), transpiration (+147%), and stomatal conductance (+64%), indicating its exceptional contribution to fortifying plant resilience under Cr stress. In mitigating oxidative stress, Se-NPs surpass Se, demonstrating a more pronounced reduction in LOX activity (−35%), MDA levels (−34%), H2O2 (−37%), and MG (−47%), showcasing heightened protection against Cr induced oxidative damage. Antioxidant defense systems also witness greater activation under Se-NPs, with higher increases in SOD (+27%), CAT (+54%), GPX (+7%), and GST (+37%) activities. Moreover, under Cr stress Se-NPs induce a more profound upregulation of antioxidant genes and the production of secondary metabolites, emphasizing its superior impact on the plant's defense mechanisms. The modulation of the ASA-GSH cycle by Se-NPs is more robust, with increased levels of ASA (+69%) and GSH (+33%), and decreased DHA (−28%) and GSSG (−29%), suggesting a more effective antioxidant network. Moreover, Se-NPs demonstrate heightened interference in Cr uptake in both root (−30%) and shoot tissues (−23%), indicating its potential to disrupt the Cr-induced ASA-GSH cycle. The study highlights the potential of Se-NPs as a more effective and sustainable approach to mitigate Cr-induced stress in plants, emphasizing the importance of understanding the underlying mechanisms and optimizing application strategies for improved agricultural sustainability and productivity in Cr-contaminated environments. Furthermore, it is necessary to conduct economic feasibility studies and assessments of the effects of Se-NP on soil microbiota in order to promote the widespread application in agricultural activities.

De-polymerisation and hydrolysis of seed storage protein is involved in the freezing tolerance of hydrated Brassica oleracea seeds

Hydrolysis of globulins might be involved in the freezing tolerance of hydrated lettuce seeds. The mechanism was further explored in hydrated brassica (Brassica oleracea) seeds, by application of 5,5'-dithiobis(2-nitro- benzoicacid) (DTNB), the Ellman's reagent, which can bind to the free sulphydryl side chain of cysteine. DTNB increased the viability of hydrated brassica seeds after slow cooling (-3°C hour-1 ) to -17°C. Two-dimensional electrophoresis and mass spectra analysis indicated the accumulation of small peptides derived from 12S globulins (cruciferin) in DTNB-treated seeds after slow cooling. The seed storage peptides with different molecular weight were cooled and the ice formation during cooling observed by cryomicroscopy, which proved that peptides of smaller molecular size produced smaller and rounder crystals. The smallest peptide in DTNB- treated seeds produced the smallest and roundest crystals during cooling. The levels of ASA, DHA and GSH were specifically up-regulated after DTNB treatment and following slow cooling, which indicates that DTNB enhanced the circulation of ASA and GSH to resist the oxidative stress. Consistent with this finding, RNA-seq and real time PCR indicated that glutathione reductase (GR) was up-regulated after DTNB treatment.

The main nutritional components in colored rice grains

Colored rice grains contain rich nutrients. To investigate the differences in nutrient composition among different colored rice varieties, LC-MS non-targeted lipidomics and targeted amino acid profiling were used to study the lipid and amino acid composition in four colored rice grains. The study analyzed the relationship between amino acids, mineral elements, crude protein (CP), crude fat (CF), carotenoids (CAROT), vitamin C (ASA), ATP, total sugar (TS), soluble protein (SP), and metabolites. A total of 505 lipid metabolites were identified. The results depicted that YZ6H had the highest levels of Arg, Asn, Met, Orn, and Try. HN had the highest levels of GABA, His, Lys, Thr, Tyr, Val, and Tau, which were significantly higher than those in YZ6H, YJN818, and YCN1H. PC (16:0/16:1,16:1/18:2,18:1/14:1,18:1/14:0,18:1/18:1,18:0/18:1), TG (16:0/18:3/22:2,22:4/18:2/18:2,16:0/20:2/20:4), and PE(20:4e/15:0) were significantly negatively correlated with GABA, Leu, Lys, Thr, Tyr, Val, Gln, His, and Ile. TG(18:2/17:1/18:2,15:0/18:2/18:2,15:0/18:2/18:3,15:0/16:0/18:2,15:0/18:1/18:2,18:1/17:1/18:2,18:1/17:1/18:1,18:1/10:1/18:1) was significantly positively correlated with Pro and Tau. YZ6H had the highest levels of ASA, SP, TS, CAROT, and ATP content. PG(28:0/18:1), MLCL(14:2/16:0/16:0), Cer(t18:0/26:0+O,d18:2/16:0,t18:0/26:0), and LPC(16:0) TG(20:4e/18:3/20:1) were significantly negatively correlated with SP, CAROT. Hex1Cer(t18:1/24:0+O), MLCL(14:2/16:0/16:0), Cer(t18:0/26:0+O,d18:2/16:0,t18:0/26:0), LPC(16:0), TG(16:0/20:2/20:4,20:4e/18:3/20:1), and DG(18:1/14:0), which are key lipid metabolites involved in the synthesis of nutritional components in colored rice grains.

Improving red pitaya fruit quality by nano-selenium biofortification to enhance phenylpropanoid and betalain biosynthesis

Red pitaya, the representative tropical and subtropical fruit, is vulnerable to quality deterioration due to climate or agronomic measures. Nano-selenium (Nano-Se) has shown positive effects on crop biofortification in favour of reversing this situation. In this study, Se could be enriched efficiently in red pitayas via root and foliar application by Nano-Se, which induced higher phenolic acids (16.9–94.2%), total phenols (15.7%), total flavonoids (29.5%) and betacyanins (34.1%) accumulation in flesh. Richer antioxidative features including activities of SOD (25.2%), CAT (33.8%), POD (77.2%), and levels of AsA (25.7%) and DPPH (14.7%) were obtained in Nano-Se-treated pitayas as well as in their 4–8 days shelf-life. The non-targeted metabolomics indicated a boost in amino acids, resulting in the stimulation of phenylpropanoid and betalain biosynthesis. In conclusion, the mechanism of Nano-Se biofortification for red pitaya might be fortifying pigment, as well as the enzymatic and non-enzymatic antioxidant substances formation by regulating primary and secondary metabolism facilitated by Se accumulation.

A non-toxic poly(resorcinol) modified glassy carbon electrode for highly selective square wave voltammetry determination of aspirin in tablet formulations and human urine samples

In this study, a sensitive square wave voltammetric method using poly(resorcinol) modified glassy carbon electrode (poly(reso)/GCE) was prepared for the determination of aspirin (ASA) in pharmaceutical tablet and biological fluid samples. CV and EIS were verify the modification of the GCE by a biosensor polymer that raised the electrocatalytic activity of poly(reso)/GCE towards an oxidation of ASA. Appearance of a single irreversible oxidative peak for ASA with fivefold current enhancement and much reduced potential at poly(reso)/GCE compared to bare GCE demonstrated catalytic property of the modifier. The peak current response with optimized experimental conditions at the poly(reso)/GCE exhibited a linear dependence with ASA concentration within the range 0.05–400.0 μM, with LoD 2.0 nM. The levels of ASA in four tablet brands ranged from 94.65 to 100.00% of their assigned values revealed the effectiveness of the developed method. The spike recovery results in pharmaceutical samples were ranged from 99.60 to 101.43% and urine samples 98.95% to 102.7%. Wider dynamic range, lower LoD, excellent spike recovery, and interference recovery results with errors <4.82% and good stability of the modifier, validated the potential applicability of the method based on poly(reso)/GCE for determination of ASA in real samples.

Over-expression of GGP1 and GPP genes enhances ascorbate content and nutritional quality of tomato

L-Ascorbic acid (AsA), a strong antioxidant, serves as an enzyme cofactor and redox status marker, modulating a plethora of biological processes. As tomato commercial varieties and hybrids possess relatively low amounts of AsA, the improvement of fruit AsA represents a strategic goal for enhanced human health. Previously, we have suggested that GDP-L-Galactose phosphorylase (GGP) and L-galactose-1-phosphate phosphatase (GPP) can serve as possible targets for AsA manipulation in tomato (Solanum lycopersicon L.) fruit. To this end, we produced and evaluated T3 transgenic tomato plants carrying these two genes under the control of CaMV-35S and two fruit specific promoters, PPC2 and PG-GGPI. The transgenic lines had elevated levels of AsA, with the PG-GGP1 line containing 3-fold more AsA than WT, without affecting fruit characteristics. Following RNA-Seq analysis, 164 and 13 DEGs were up- or down-regulated, respectively, between PG-GGP1 and WT pink fruits. PG-GGP1 fruit had a distinct number of up-regulated transcripts associated with cell wall modification, ethylene biosynthesis and signaling, pollen fertility and carotenoid metabolism. The elevated AsA accumulation resulted in the up regulation of AsA associated transcripts and alternative biosynthetic pathways suggesting that the entire metabolic pathway was influenced, probably via master regulation. We show here that AsA-fortification of tomato ripe fruit via GGP1 overexpression under the action of a fruit specific promoter PG affects fruit development and ripening, reduces ethylene production, and increased the levels of sugars, and carotenoids, supporting a robust database to further explore the role of AsA induced genes for agronomically important traits, breeding programs and precision gene editing approaches.

Physiological Mechanism of Exogenous 5-Aminolevulinic Acid Improved the Tolerance of Chinese Cabbage (Brassica pekinensis L.) to Cadmium Stress

The 5-aminolevulinic acid (ALA), a new type of plant growth regulator, can relieve the toxicity of cadmium (Cd) to plants. However, its mechanism has not been thoroughly studied. In the study, the roles of ALA have been investigated in the tolerance of Chinese cabbage (Brassica pekinensis L.) seedlings to Cd stress. The results showed that Cd significantly reduced the biomass and the length of the primary root of seedlings but increased the malondialdehyde (MDA) and the hydrogen peroxide (H2O2) contents. These can be effectively mitigated through the application of ALA. The ALA can further induce the activities of antioxidant enzymes in the ascorbate-glutathione (AsA-GSH) cycle under Cd stress, which resulted in high levels of both GSH and AsA. Under ALA + Cd treatment, the seedlings showed a higher chlorophyll content and photosynthetic performance in comparison with Cd treatment alone. Microscopic analysis results confirmed that ALA can protect the cell structure of shoots and roots, i.e., stabilizing the morphological structure of chloroplasts in leaf mesophyll cells. The qRT-PCR results further reported that ALA downregulated the expressions of Cd absorption and transport-related genes in shoots (HMA2 and HMA4) and roots (IRT1, IRT2, Nramp1, and Nramp3), which resulted in the low Cd content in the shoots and roots of cabbage seedlings. Taken together, the exogenous application of ALA alleviates Cd stress through maintaining redox homeostasis, protecting the photosynthetic system, and regulating the expression of Cd transport-related genes in Chinese cabbage seedlings.

Improving Capacity of Yellow Corn Tolerance to Water Stress by Foliar Application of Ascorbic Acid and Hydrogen Peroxide

Two field experiments were conducted in a new soil conditions in the extension field in El Qantra- West, Ismailia Governorate, Egypt (300 58/ N, 320 23/ E, and 10m above mean sea level) during 2016 and 2017 summer seasons. The study aimed to find out the effect of five exogenous application levels of AsA and H2O2 on yellow corn hybrid 352 (three way cross) under three amounts of irrigation water (1.00. 0.80 and 0.60 of the estimated crop evapotranspiration) using surface irrigation system. A randomized complete block split-plot design with three replications was used in each season. The irrigation treatments and the levels of AsA and H2O2 were randomly allocated in the main and sub-plots, respectively. The most important findings could be summarized as follows: Irrigation by 2250 m3/fad (severe water stress) instead of 3750 m3/fad (full irrigation) reduced ear leaf blade area, total chlorophyll and relative water content in both seasons. Increasing the level of AsA up to 350ppm/fad increased ear leaf blade area, total chlorophyll and relative water content followed by the highest level of H2O2 (60mM H2O2). Decreasing irrigation water significantly reduced ear length, 100-grain weight and grain yield/fad. Meanwhile, ear length, 100-grain weight and grain yield/fad were significantly obtained from the highest level of AsA followed by the highest levels of H2O2 compared with their untreated analogues. The interaction between the both studied factors showed that application of 350ppm AsA and 60mM H2O2 treatments protected about 920 and 320 kg/fad grains from collapse under moderate water stress (3000 m3/fad). Meanwhile, under severe water stress, treatments by same levels of AsA and 30mM H2O2 protected about 670 and 330kg/fad grains from lose. Application of 350ppm AsA saved approximately 750m3/fad of irrigation water without yield reduction.

Trait motivational reactivity as a predictor of online dating app behavior

Online dating apps have become an increasingly common way to meet prospective partners and form relationships. Though previous research lends insight into who uses these platforms and why, relatively little is known about the nature of in-app behavior during that usage. The current study directly monitors sessions of dating app usage, observing how users cycle through and then make decisions about assortments of potential partners. Adopting a motivated cognition perspective (Lang, 2006), trait levels of appetitive (ASA) and defensive motivational reactivity (DSA) were found to significantly influence a variety of in-app behaviors. Specifically, individuals with relatively lower trait levels of DSA and higher levels of trait ASA were found to browse prospective partner profiles at the fastest rate. Further, trait DSA was positively associated with the amount of information sought before a decision was made to “like” or reject a prospective partner, with this effect moderated by trait ASA. Finally, trait DSA of the app user was negatively associated with the likelihood of a given profile being liked. These results provide new empirical insight into patterns of behavior occurring within sessions of dating app usage. Additionally, they highlight a special consideration for applying a motivated cognition perspective to predict media choices with motivationally-relevant real-world implications: namely, the possibility that trait motivation tendencies in external offline behavior may influence the usage of media with related consequences.

Patients with Essential Thrombocythemia may be Poor Responders to Enteric-Coated Aspirin, but not to Plain Aspirin.

Essential thrombocythemia (ET) patients are treated with aspirin (acetylsalicylic acid [ASA]) to prevent thrombosis. Previous studies showed that serum thromboxane (Tx) B2 was high 24 hours after enteric-coated (EC)-ASA in ET patients, due to increased number of noninhibited reticulated platelets (RPs), consequent to high platelet turnover, and that ASA should be given twice a day to ET patients. We studied ET patients (n = 17) and healthy subjects (n = 10) on 100 mg EC-ASA once daily; experiments were repeated after 14-day treatment with 100 mg plain-ASA once daily. Serum TxB2, plasma ASA, and salicylic acid (SA) were measured before the morning dose and up to 8 hours thereafter. Blood activity of ASA-deacethylating esterases, in vitro inhibition of collagen-induced TxB2 production by ASA (10-1,000 µM), and number of RP were measured. TxB2 inhibition by ASA in vitro and esterases activities were normal in all subjects. EC-ASA elicited highly variable responses; 6 ET patients were poor responders, as their serum TxB2 was high after EC-ASA; their plasma levels of ASA and SA were low/undetectable. In contrast to EC-ASA, plain ASA decreased serum TxB2 and increased plasma ASA and SA in all subjects. Serum TxB2 was high in ET patients at 24 hours and significantly correlated with RP count (but not RP percentage) and platelet count. Plain ASA should be used in ET patients to inhibit platelets efficiently. The identification of ET patients who might benefit from twice a day ASA could simply be based on their platelet count: since their platelet turnover is not increased, ET patients with normalized platelet count should not need twice a day ASA treatment.

Inhibitory effect of propyl gallate on pulp breakdown of longan fruit and its relationship with ROS metabolism

Abstract An excessive ROS accumulation in harvested longan (Dimocarpus longan Lour.) fruit could promote the pulp breakdown and lower the fruit quality. To solve this problem, the influence of propyl gallate, one kind of ROS scavenger, on the ROS metabolism in pulp of postharvest longans and its connection with the breakdown occurrence of longan pulp were investigated. Contrasted to control samples, the propyl gallate-treated group manifested a lower index of pulp breakdown, MDA content, and production rate of O2−., but higher gene expression levels of DlSOD, DlCAT and DlAPX, higher SOD, CAT and APX activities, higher levels of AsA, flavonoid, GSH and total phenolics, and higher ability of scavenging free radicals. These results revealed that propyl gallate inhibited longan pulp breakdown occurrence, which was because propyl gallate enhanced the ROS scavenging ability and reduced ROS generation and accumulation in longan pulp. These activities involved alleviating the oxidative damage of cell membrane and the peroxidation of membrane lipid in longan pulp, which maintained the structural integrity of longan pulp cell membrane and suppressed the pulp breakdown occurrence in postharvest longan fruit.

Influence of dietary inosine and vitamin C supplementation on growth, blood chemistry, oxidative stress, innate and adaptive immune responses of red sea bream, Pagrus major juvenile

Both inosine (INO) and vitamin C (l-ascorbic acid, AsA) play important roles in growth performance, feed utilization and health status of fish. Therefore, a 56 days feeding trial was conducted to determine the interactive effects of dietary INO and AsA on growth performance, oxidative status, innate and adaptive immune responses of red sea bream. Fish growth performance and fed utilization parameters were significantly affected by dietary INO supplementation but not by AsA. Fish fed diets with INO at 4 g kg−1 diet in combination of high and low levels of AsA (3.1 g kg-1 and 9.3 g kg-1) produced the highest growth and feed utilization performances. In terms of growth and feed utilization performances no significant interaction effects were observed between INO and AsA. Dietary INO significantly influenced hematocrit, glucose and glutamyl oxaloacetic transaminase (GOT) content of red sea bream meanwhile AsA also significantly influenced hematocrit, glucose, total cholesterol, blood urea nitrogen (BUN) and glutamic-pyruvate transaminase (GPT) content of the test fish. No significant interaction effects was also observed between INO and AsA on measured hematological parameters. Reactive oxygen metabolites (d-ROMs) significantly influenced by both INO and AsA. Fish fed diet groups D1, D4 and D6 showed best oxidative stress resistance. Only INO was a significant factor on nitro-blue-tetrazolium activity (NBT) and bactericidal activity (BA). Neither INO nor AsA was a significant factor on serum catalase activity (CAT), total serum protein (TSP), peroxidase activity (PA) and lysozyme activity (LA). No significant interaction effects was observed between INO and AsA on measured innate immune parameters. Agglutination antibody titer was significantly influenced by dietary supplementation, after 15 days of vaccination but not in 21 days. In the day 15th fish and diet group D3 and D5 showed significantly higher values compared to diet groups control and D1. INO was the only significant factor of increasing agglutination antibody titer in 15 t h day. While AsA was not a significant factor on agglutination antibody titer values in day 15 t h, there was an interaction between dietary INO and AsA levels. Finally under the experimental conditions, fish fed high INO and low AsA levels (4 g kg−1 and 0.31 g kg−1 diet, respectively) showed best growth and feed utilization performance. Simultaneously, low level of INO and high level of AsA (2 g kg−1 and 0.93 g kg−1 diet, respectively) improved blood chemistry and immunological parameters. Furthermore, combined use of INO and AsA is possible to improve hemato-immunological responses of red sea bream.

P.3.005 - Interactions of oxytocin receptor gene variation with behavioural inhibition and adult separation anxiety in complicated grief

Complicated grief (CG) refers to the severe and prolonged (≥ 6 months) grief reaction following the loss of a beloved person that occurs in approximately 10 – 20% of bereaved individuals and is associated with an increased risk for the development of depression and anxiety disorders [1]. So far, the underlying processes contributing to the vulnerability to CG are not yet well understood but likely comprise the complex interplay of genetic, temperamental and psychological factors that interactively influence the severity and persistence of grief reactions. In light of its central role in social behavior, stress regulation and attachment, the oxytocin receptor (OXTR) gene may play a key role in the conferral of CG. Additionally, temperamental traits such as behavioral inhibition (BI) or psychological characteristics such as symptoms of separation anxiety (SA) may predispose to the development of CG. For instance, adult SA has been linked to higher symptom severity and impairment in individuals with CG [2]. Therefore, the present study for the first time aimed to address the involvement of OXTR gene variation in the emergence of CG and the potential moderating effects of BI and SA. To this end, 96 adult outpatients (70 female, 26 male; mean age ± SD = 39.96 ± 12.71 years) with DSM-IV mood and anxiety disorders were assessed for CG using the Inventory of Complicated Grief (ICG). All patients were genotyped for OXTR rs2254298 and characterized for BI using the Retrospective Self-Report of Inhibition (RSRI) and SA symptoms using the Adult Separation Anxiety Scale (ASA-27). Patients were grouped according to genotype (GG vs. AG/AA carriers). The influence of grouped OXTR genotype, RSRI and ASA-27 scores, respectively, on ICG score was investigated via hierarchical multiple regression analyses. No differences were observed with regard to age, sex, or questionnaire scores (all p ≥ 0.05). No main effects of OXTR genotype, RSRI or ASA-27 scores on CG were observed, however ICG scores differed as a function of OXTR genotype and RSRI score (OXTR x BI, p=0.031), and, on a trend-level, ASA-27 score (OXTR x ASA, p=0.064). Specifically, in patients homozygous for the OXTR G allele, increased levels of both BI and ASA were related to higher ICG scores. Of note, this pattern appears to be reversed under conditions of low BI or low ASA. In line with the ‘differential susceptibility hypothesis’ [3], the present findings suggest that while OXTR GG genotype carriers are more vulnerable to the development of CG in the presence of risk-increasing factors, they at the same time are the least likely to develop CG in the absence of these risk factors. Taken together, the present results for the first time provide evidence for an interaction of OXTR gene variation with BI and potentially also symptoms of adult SA in the moderation of clinically relevant grief reactions and may therefore inspire new insights into the development and improvement of therapeutic options in the prevention and treatment of CG.

Changes in soluble sugar metabolism in loquat fruit during different cold storage.

To investigate soluble sugar metabolism and its relationship to chilling injury (CI), loquat fruits were stored at 0 and 5°C for 5weeks. CI symptoms were monitored during storage, and soluble sugar content and related enzyme activities were measured. Enzymes activities and substrate levels in the ascorbate-glutathione (AsA-GSH) cycle were also determined. Fruit at 0°C had lower sucrose levels and higher levels of glucose and fructose than fruit maintained at 5°C, and also manifested less severe CI symptoms. Fruit at 0°C also exhibited increased activities of acid invertase, neutral invertase, sucrose phosphatesynthase and sucrose synthase. AsA-GSH cycle activity at 0°C was much higher than that at 5°C. Glucose levels correlated positively with levels of AsA and GSH and ascorbate peroxidase (APX) activity. The increased glucose levels are sufficient to account for the chilling tolerance of loquat fruit.

Expression profiles of the genes involved in l-ascorbic acid biosynthesis and recycling in Rosa roxburghii leaves of various ages

Vitamin C (l-ascorbic acid, AsA) serves as an antioxidant and enzyme cofactor in plants. Rosa roxburghii Tratt is a rose species that is recognized for its high AsA content. However, leaf AsA metabolism has not been explored in detail, especially at the gene expression level. In the present study, AsA accumulation and the relative expression levels of genes putatively involved in AsA biosynthesis and recycling, as well as enzyme activities in leaves of different ages were investigated. Leaf AsA content remained at its highest level during the first 50 days of development, and then markedly decreased, which correlated with the expression and activity of monodehydroascorbate reductase (MDHAR) (p < 0.05). The dehydroascorbate (DHA) and T-AsA (AsA + DHA) contents increased with leaf development. Both of them reached the peak in 50-day-old leaves and then decreased rapidly. The highest expression levels of three genes, i.e. l-galactono-1,4-lactone dehydrogenase (GalLDH), d-galacturonic acid reductase (GalUR), and myo-inositol oxygenase (MIOX) involved in AsA synthesis were observed in 50-day-old leaves, although only GalUR strongly correlated with the rate of T-AsA accumulation (p < 0.05). Furthermore, incubating leaf discs in vitro with its precursor candidates showed that d-galacturonic acid (d-GalUA) was the most effective precursor of AsA biosynthesis. These results suggest that Rosa roxburghii leaves accumulated high levels of AsA (9 μmol g−1 FW at most), especially at young to mature ages. AsA and AsA pool size accumulation in the leaves were regulated by both biosynthesis and recycling, and GalUR in the GalUA pathway and MDHAR in the recycling pathway could play important roles in this process.

Melatonin Increases the Chilling Tolerance of Chloroplast in Cucumber Seedlings by Regulating Photosynthetic Electron Flux and the Ascorbate-Glutathione Cycle.

The aim of the study was to monitor the effects of exogenous melatonin on cucumber (Cucumis sativus L.) chloroplasts and explore the mechanisms through which it mitigates chilling stress. Under chilling stress, chloroplast structure was seriously damaged as a result of over-accumulation of reactive oxygen species (ROS), as evidenced by the high levels of superoxide anion (O2−) and hydrogen peroxide (H2O2). However, pretreatment with 200 μM melatonin effectively mitigated this by suppressing the levels of ROS in chloroplasts. On the one hand, melatonin enhanced the scavenging ability of ROS by stimulating the ascorbate–glutathione (AsA–GSH) cycle in chloroplasts. The application of melatonin led to high levels of AsA and GSH, and increased the activity of total 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 1.5.5.1), glutathione reductase (GR, EC1.6.4.2) in the AsA–GSH cycle. On the other hand, melatonin lessened the production of ROS in chloroplasts by balancing the distribution of photosynthetic electron flux. Melatonin helped maintain a high level of electron flux in the PCR cycle [Je(PCR)] and in the PCO cycle [Je(PCO)], and suppressed the O2-dependent alternative electron flux Ja(O2-dependent) which is one important ROS source. Results indicate that melatonin increased the chilling tolerance of chloroplast in cucumber seedlings by accelerating the AsA–GSH cycle to enhance ROS scavenging ability and by balancing the distribution of photosynthetic electron flux so as to suppress ROS production.

Nitrate reductase-mediated nitric oxide production alleviates Al-induced inhibition of root elongation by regulating the ascorbate-glutathione cycle in soybean roots

Although the studies on nitric oxide (NO) in Al toxicity has been reported, the results are controversial. The aim of this study is to investigate the role of NO in Al-induced root growth inhibition in soybean (Glycine max L.). NO donor and scavenger were used to test the effects of NO on root elongation, lipid peroxidation, reactive oxygen species (ROS) accumulation, and ascorbate-glutathione cycle (AsA-GSH) under Al stress. Application of butylated hydroxyanisole, a lipophilic antioxidant, reduced Al-induced lipid peroxidation and root inhibition. NO donor alleviated Al-induced root inhibition and ROS accumulation as well as lipid peroxidation, while NO scavenger aggravated the observed effects of Al. In addition, NO accumulation in root apexes under Al stress was mediated by nitrate reductase (NR). Furthermore, the levels of GSH and AsA were enhanced by Al and further elevated by NO donor, but suppressed by NO scavenger. Moreover, the activities of key enzymes in AsA-GSH cycle were positively regulated by NO under Al stress. These results indicate that NR-mediated NO improves Al-induced root growth inhibition, possibly through its regulation of AsA-GSH cycle to maintain high levels of AsA and GSH, subsequently reducing ROS accumulation and thus alleviating lipid peroxidation.