Anion Levels Research Articles

Effect of the Introduction of ZnII and CdII Ions on EuIII and TbIII Emission in M2Ln2 Heterometallic Molecules With 2‐Furoic Acid Anions

ABSTRACTHeterometallic d‐4f coordination complexes are of paramount interest in modern coordination chemistry because of their potential applications in organic light‐emitting devices and spintronic materials. Here we report the synthesis and thorough investigation of Ln and MLn (M = Zn, Cd; Ln = Sm, Eu, Gd, Tb) molecular complexes based on 2‐furancarboxylic acid anion (Hfur): [Ln2(NO3)2(fur)4(DME)2] (Ln = Eu, Gd, Tb; DME is dimethoxyethane) and [M2Ln2(NO3)2(fur)8(bpy)2] (M = Zn, Cd; Ln = Eu, Gd, Tb, Sm; bpy is 2,2′‐bipyridyl). The structure and isostructural nature of compounds were determined based on the single‐crystal and powder X‐ray diffraction data. The photophysical properties of the obtained compounds were studied in detail: The energies of the triplet levels of the furoate anion and d‐blocks {M(fur)2(bpy)} (M = Zn, Cd), the relaxation times of the excited states, and the quantum yields were determined. Critical step from Ln complexes to ZnLn and CdLn (Ln = Eu, Tb) is accompanied by an increase in quantum yields, which correlates with a change in the energy of the triplet level of the aromatic part of the complexes and with the results of quantum chemical calculations indicating different schemes for the origination of triplet levels in MLn compounds.

Elucidating the eco-friendly herbicidal potential of microbial metabolites from Bacillus altitudinis.

Microbial herbicides play a vital role in agricultural preservation, amid growing concerns over the ecological impact from extensive development and use of chemical herbicides. Utilizing beneficial microbial metabolites to combat weeds has become a significant focus of research. This study focused on isolating herbicidal active compounds from Bacillus altitudinis D30202 through activity-guided methods. First, the n-butanol extract (n-BE) of B. altitudinis D30202 underwent fractionation using macroporous adsorption resin D101 and Sephadex LH-20, identifying Fr. F as the most potent segment against wild oats (Avena fatua L.). Ultra-performance liquid chromatography - quadrupole time-of-flight mass spectrometry (UPLC - QTOF-MS) identified nine compounds in the active fraction Fr. F. Subsequently, three subfractions (Fr.F-1 to Fr.F-3) were derived from Fr.F via semi-preparative liquid chromatography, resulting in methyl indole-3-acetate (MeIAA) purification. MeIAA, functioning as an auxin analog, exhibited effects of indole-3-acetic acid (IAA) on wild oats' growth, with a root length median inhibitory concentration of 81.06µg/ml. Furthermore, we assessed MeIAA's herbicidal impact on five weed species across diverse families and genera, providing a first-time analysis of MeIAA's mechanism on wild oats. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed structural damage to leaves and roots post-MeIAA treatment. MeIAA treatment increased superoxide anion and hydrogen peroxide levels in wild oat roots, alongside with elevated peroxidase (POD) and superoxide dismutase (SOD) activity, chlorophyll-degrading enzymes (Chlase, MDACase), malondialdehyde (MDA) content, and relative conductivity in leaves. Conversely, it decreased catalase (CAT) activity and chlorophyll content. Therefore, this study provides a new material source and theoretical foundation for ecologically sustainable agricultural weed control.

Resistance artery vasodilator pathways involved in the antihypertensive effects of cocoa shell extract in rats exposed to fetal undernutrition.

Fetal undernutrition establishes the foundations for hypertension development, with oxidative stress being a key hallmark. A growing interest in nutraceuticals for treating hypertension and environmental waste concerns prompted the present study aiming to evaluate whether supplementation with a polyphenol enriched extract from cocoa shell (CSE), a by-product from the chocolate industry with antioxidant properties, reduces hypertension of developmental origin, thus improving mesenteric resistance artery (MRA) vasodilatation. Adult male and female offspring from rats exposed to 50% food restriction from mid-gestation (maternal undernutrition, MUN) and controls were used. Supplementation was given through a gelatine (vehicle, VEH) or containing CSE (250mgkg-1day-1) 5daysweek-1 for 3weeks. Systolic blood pressure (SBP) was assessed by tail-cuff plethysmography. MRA function was studied by wire myography, and superoxide anion and nitric oxide were investigated by fluorescent indicators and confocal microscopy. Compared to control-VEH, MUN-VEH males showed significantly higher SBP, reduced MRA as well as relaxation to ACh, sodium nitroprusside and the AMPK agonist 5-aminoimidazole-4-carboxamide riboside, but not to isoproterenol. In MUN males, endothelial endothelium-derived hyperpolarizing factor and nitric oxide were unaltered, but MRA released a vasoconstrictor prostanoid and produced higher levels of superoxide anion. CSE normalized blood pressure and improved all above-mentioned MRA alterations in MUN males without an effect on control counterparts, except the reduction of superoxide anion. MUN-VEH females were normotensive and only showed a tendency towards larger superoxide anion production, which was abolished by CSE. CSE supplementation reduces SBP improving endothelium-dependent and independent MRA vasodilatation, related to local superoxide anion reduction, being a potential nutraceutical ingredient to counteract hypertension, in addition to contributing to the circular economy. KEY POINTS: Fetal undernutrition induces hypertension in males associated with deficient resistance artery vasodilatation, being normalized by cocoa shell extract (CSE). Release of a cyclooxygenase-derived contractile factor is the main endothelial alteration, which is abolished by CSE. AMPK and soluble guanylyl cyclase-mediated relaxation are also reduced in smooth muscle cells from maternal undernutrition resistance arteries, being improved by CSE. Vascular oxidative damage caused by excess superoxide anion generation can account for impaired vasodilatation, which is improved by CSE. The capacity of CSE to improve relaxation is probably related to its antioxidant bioactive factors, and thus cocoa shell is a potential food by-product to treat hypertension.

Plant-derived biochar and salicylic acid as biostimulants for Lycopersicon esculentum under chromium toxicity conditions: Insights from physiochemical attributes, antioxidants, and relative gene expression

Chromium is a widespread toxic trace metal in cultivated lands owing to human actions, insufficient treatment, and unregulated disposal. Chromium toxicity is facilitated by the production of reactive oxygen species, which induce lipid peroxidation and damage the cellular membranes and nuclei. This study evaluated the preparation and characterization of Pterospermum-derived biochar based on a set of test categories from the International Biochar Initiative. The aim of this study was to assess the effectiveness of Pterospermum-derived biochar and salicylic acid (SA) in promoting the growth and biochemical attributes of tomato plants grown in Cr-contaminated soils. The results showed that Cr toxicity reduced root (42.86 %) and shoot (23.26 %) lengths, which subsequently increased (65 % root and 39.94 % shoot lengths) under SA and biochar treatments. Increased levels of superoxide anions (O2•-) (104.43 %), malondialdehyde (MDA) (115.53 %), and H2O2 (72.35 %) were observed in the Cr-treated tomato plantlets. The combined treatment of SA and biochar effectively reduced MDA, H2O2, and O2•- levels by 51.17 %, 36.89 %, and 45.53 %, respectively, under Cr toxicity conditions. In addition, the combined treatment with SA and biochar enhanced the activity and gene expression of dehydrogenase (7.06-fold), guaiacol peroxidase (6.51-fold), superoxide dismutase (7.90-fold), polyphenol oxidase (1.89-fold), glutathione-s-transferase (2.55-fold), ascorbate peroxidase (1.26-fold), and glutathione peroxidase (8.75-fold) under Cr toxicity conditions. The results highlight the combined treatment of biochar and SA as an effective amendment that offers an environment-friendly method for alleviating Cr toxicity and promoting growth and the antioxidative defense system in tomato plantlets.

Physiological and metabolomic analyses reveal the mechanism by which exogenous spermine improves drought resistance in alfalfa leaves (Medicago sativa L.).

Alfalfa (Medicago sativa L.) is a globally important legume crop with high nutritional and ecological value. Drought poses a serious threat to alfalfa acreage and yields. Spermine (Spm) has been shown to protect plants from drought damage. The aim of this study was to clarify the mechanism of exogenous Spm to improve drought resistance of alfalfa. In this study, we root applied 0.1, 0.5, and 1 mM Spm to Gannong No. 3 (G3) alfalfa under drought stress, and then determined their physiological and metabolic changes. The results showed that exogenous Spm increased chlorophyll content, chlorophyll fluorescence parameters and gas exchange parameters, enhanced antioxidant enzymes activity, improved ascorbic acid-glutathione (AsA-GSH) cycle, increased osmoregulatory substances content, reduced hydrogen peroxide and superoxide anion levels, and inhibited malondialdehyde accumulation in alfalfa under drought stress, thereby increasing plant height and leaf relative water content and enhancing drought tolerance of alfalfa. The redundancy analysis of the above physiological indicators showed that the addition of the optimal Spm to improve drought tolerance of alfalfa under drought stress was mainly achieved by increasing catalase activity and improving the ASA-GSH cycle. In addition, metabolomics analysis revealed that exogenous Spm increased the content of oxobutanedioic acid, citric acid, fumaric acid and malic acid to enhance the tricarboxylic acid cycle. Meanwhile, exogenous Spm increased endogenous Spm and proline (Pro) content to resist drought stress by enhancing Spm and Pro metabolism. Moreover, exogenous Spm increased the accumulation of the signaling substance abscisic acid. In conclusion, exogenous Spm enhanced drought resistance of alfalfa leaves under drought stress.

Source Minerals for the Release of Salinity in the Groundwater: A Case Study of Pratapgarh District, Uttar Pradesh, India

ABSTRACT The aim of this study is to determine the salinity of groundwater, identify the nature of its sources, and to understand the physicochemical conditions that cause high level of salinity to be discharged into groundwater. There are several factors that influence groundwater salinity, including water quality, soil type, irrigation techniques, and groundwater depth. A total of 40 ground water samples were collected from dug wells, tube wells, and hand pumps in salinity-affected areas and analysed using physicochemical variables. A total of 11 sediment samples were collected and analysed for lithology and mineralogy. Due to high level of cations and anions in the groundwater, the study area is highly contaminated. It was observed that the leaching of salt is highly dependent on sediment types and salt-bearing minerals. Attempts were also made to determine the various depth zones responsible for release of salt in shallow aquifers. For sedimentological and mineralogical studies, a piezometer was installed at a maximum depth of 33 m below the ground surface. Based on the results of the study, it was observed that groundwater chemistry is primarily influenced by water-rock interactions, ion exchange processes, weathering (carbonate and silicate), and evaporation. These research findings will contribute to more effective sustainable groundwater management in areas with water scarcity and it will also boost the Indian economy.

Biochar Increases Rice Yield in Soda Saline-Alkali Paddy Fields by Improving Saline-Alkali Stress and Phosphorus Use Efficiency

Soda saline-alkali significantly hinders rice growth, phosphorus utilization efficiency, and yield formation. The application of biochar can alleviate the adverse effects of saline-alkali stress on crops. However, there is limited research on the interaction between biochar and phosphorus fertilizer concerning ionic accumulation, phosphorus utilization efficiency, and rice yield in soda saline-alkali soils. A two-year field experiment was conducted to study the combined effects of biochar and phosphate fertilizer on ionic accumulation, physiological status, phosphorus utilization efficiency, and rice yield in soda saline-alkali soil. Four treatments were established for the study: NK (225 kg N, 75 kg K ha−1 year−1), NPK (225 kg N, 70 kg P, 75 kg K ha−1 year−1), NK + B [225 kg N, 75 kg K ha−1 year−1, 1.5% biochar (w/w)], and NPK + B [225 kg N, 70 kg P, 75 kg K ha−1 year−1, 1.5% biochar (w/w)]. The findings indicated that the combined application of biochar and phosphorus fertilizer (NPK + B) significantly reduced the Na+ concentration, Na+/K+ ratio, malondialdehyde (MDA), superoxide anion (O2−), and hydrogen peroxide (H2O2) levels in rice plants. Furthermore, it resulted in a significant increase in K+ concentration and elevated the levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), proline (Pro), soluble protein (SP), soluble sugar (SS), and acid phosphatase (ACP). The NPK + B treatment exhibited a significant difference compared to the other treatments (p < 0.05). Compared with NK, phosphorus accumulation and phosphorus utilization efficiency under NPK + B were significantly increased (p < 0.05). The average of biomass yield, grain yield, and harvest index of NPK + B, NK + B, and NPK significantly surpassed those of NK by 6.28–12.25%, 19.80–42.13%, and 11.59–24.64%, respectively. Moreover, a significant difference was observed between NPK + B and the other treatments (p < 0.05). Principal component analysis of the two-year mean data revealed a strong positive correlation of 89.5% for PC1 and a minor negative correlation of 4.4% for PC2. Our research findings demonstrate that the combination of biochar and phosphorus fertilizer effectively enhances salt and alkali tolerance in rice plants, resulting in increased yield through improved ionic balance and physiological status.

Effects of uric acid on oxidative stress in vascular smooth muscle cells.

Hyperuricemia during hypertension is associated with aberrant vascular functions and increased oxidative stress, which affects endothelial dysfunction. Nevertheless, the molecular mechanisms underlying the effects of uric acid on vascular smooth muscle cells (VSMCs) through oxidative stress remain unclear. The aim of the present study was to investigate the dose- and time-dependent effects of uric acid on oxidative stress and p53 protein expression in VSMCs. VSMCs were incubated with various concentrations of uric acid (0-50 mg/dl) for different time periods (1-24 h). Thiobarbituric acid reactive substances (TBARs), protein carbonylation and nitric oxide (NO) levels were determined using appropriate assay kits. Superoxide anion release was detected using the Görlach method. Western blotting was performed to determine the protein expression levels of p53. The findings demonstrated that the application of uric acid led to an increase in protein carbonylation and superoxide anion levels while causing a decrease in NO levels. Conversely, no significant effect was observed on TBARS levels. Additionally, it was observed that high concentrations of uric acid suppressed p53 expression at 6, 12 and 24 h. The present study provided evidence that the influence of uric acid on oxidative stress was more closely associated with time than dose; however, not all effects observed were strictly time-dependent.

Exogenous nitric oxide treatment delays the senescence of postharvest mung bean sprouts by regulating ascorbic acid metabolism.

This study evaluated the effects of nitric oxide (NO) treatment on ascorbic acid (AsA) metabolism and mung bean sprout quality. It examined changes in the AsA content, enzyme activity associated with AsA metabolism, antioxidant capacity, cell membrane composition, and cellular structure to clarify the effects of NO on mung bean sprouts. Nitric oxide treatment preserved mung bean sprout quality by enhancing significantly the activity of enzymes involved in the l-galactose pathway (including guanosine diphosphate (GDP)glutathione (-d-mannose pyrophosphorylase, GDP-mannose-3',5'-epimerase, GDP-l-galactose phosphorylase, l-galactose-1-phosphate phosphatase, l-galactose dehydrogenase, and l-galactose-1,4-lactone dehydrogenase) and the AsA-glutathione (GSH)(Beijing Solarbio Science and Technology Co.,Ltd., Beijing, China) cycle (including ascorbate peroxidase, ascorbic acid oxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate reductase) during the germination and storage stage. Increased enzyme activity led to an increase in AsA content and enhanced antioxidant capacity, and reduced the membrane lipid damage in mung bean sprouts. This was demonstrated by higher levels of DPPH radical scavenging capacity, unsaturated fatty acids and phospholipids, along with lower levels of hydrogen peroxide, superoxide anions, and malondiadehyde, in NO-treated mung bean sprouts. Scanning electron microscopy also revealed that NO treatment maintained the integrity of the cellular structure of the mung bean sprouts. Nitric oxide accelerates AsA metabolism effectively by regulating the biosynthesis and regeneration of AsA in mung bean sprouts. These changes increased AsA levels, alleviated membrane lipid damage, delayed senescence, and maintained the quality of mung bean sprouts during storage. © 2024 Society of Chemical Industry.

Functional Identification of MhPYL4 Involved in Iron-Deficiency Stress in Malus Halliana Koehne.

The PYL protein family are crucial sensors of the core signals of abscisic acid (ABA) and significantly influence the plant's response to ABA-mediated abiotic stresses as well as its growth and development. However, research on the role of the MhPYL4 gene in iron (Fe) deficiency in apple trees is limited. Studies have shown that the MhPYL4 gene, when exposed to Fe-deficiency stress, exhibits more rapid transcriptional upregulation than other genes' quickly elevated transcription. However, the precise mechanism by which it alleviates this stress remains unclear. The MhPYL4 gene (ID:103432868), isolated from Malus halliana, was analyzed to elucidate its function. Arabidopsis plants engineered to overexpress the MhPYL4 gene exhibited increased leaf chlorosis and slower growth in response to Fe stress compared to the unmodified controls. The transgenic plants also exhibited elevated levels of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, as well as ferric chelate reductase (FCR) activities. Levels of malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2-) were increased. In addition, these transgenic plants had lower concentrations of proline (Pro) and Fe2+, which indicated that their stress tolerance was reduced. Similarly, the overexpression of MhPYL4 in apple calli resulted in inhibited growth and increased susceptibility under Fe stress conditions. Physiological evaluations indicated that the overexpression of MhPYL4 in Arabidopsis reduced its Fe stress tolerance by inhibiting chlorophyll synthesis. In apple calli, it altered pH levels, antioxidant enzyme activity, and Fe-reducing capabilities under the same stress conditions. In summary, the elevated expression of the MhPYL4 gene reduced the tolerance of both Arabidopsis and apple calli to Fe stress, suggesting that MhPYL4 acts as a negative regulator in response to Fe deficiency.

Investigation of laccase activity in cholinium-based ionic liquids using experimental and molecular dynamics techniques

Laccases hold great potential for biotechnological applications, particularly in environmental pollutant remediation. Laccase activity is governed by the solvent environment, and ionic liquids (ILs) emerge as a versatile solvent for activation or stabilization of enzymes. Herein, effects of cholinium-based ILs formulated with carboxylic acids, inorganic acid, and amino acids as anionic species, on the catalytic activity of laccase from Trametes versicolor were investigated by experimental and computational approaches. Experimental results showed that laccase activity was enhanced by 21.39 % in 0.5 M cholinium dihydrogen citrate ([Cho][DHC]), in relation to the laccase activity in phosphate buffer medium. However, cholinium aminoate ILs negatively affected laccase activity, as evidenced by the partial deactivation of laccase in both cholinium glycinate and cholinium phenylalaninate, at concentrations of 0.1 M and 0.5 M, respectively. Molecular dynamics studies revealed that the enhancement of laccase activity in [Cho][DHC] might be attributed to the highly stabilized and compact structure of laccase, facilitating a better internal electron transfer during the laccase-substrate interactions. Enhanced catalytic performance of laccase in [Cho][DHC] was postulated to be driven by the high accumulation level of dihydrogen citrate anions around laccase's surface. [Cho][DHC] holds great promise as a cosolvent in laccase-catalyzed biochemical reactions.

Metabolic and Biochemical Performances of Abaca (<i>Musa textilis</i> Née) under Intermediate and Advanced Phase Agroforestry System

Abaca, one of the potential fiber crops with high-quality fiber and promising economic value, is mainly established under the agroforestry system, for it is considered a non-primary crop. The study aims to observe the metabolic and biochemical performance as well as the fiber quality of abaca under the agroforestry system. The experimental design used in this study was nested with two types of agroforestry systems, i.e., intermediate phase (Fase Tengah, FT) and advanced phase (Fase Lanjutan, FL) and was conducted during the rainy season. Parameters observed in this study were divided into edaphic and climatic parameters, oxidative response parameters, foliage macro- and micronutrient, and fiber quality. Despite poor soil quality compared to FL, higher relative humidity (4.35%), lower temperature (2.73%), and lower shading intensity were observed in FT. Improved soil characteristics in FL, viz. soil water content (19.64%), organic carbon (72.89%), porosity (4.29%), cation exchange capacity (13.77%), and pH (35.13%), were unable to compensate plant stress induced by the high shading intensity at 83.99%. Consequently, it contributed to higher levels of malondialdehyde, superoxide anion, hydrogen peroxide, superoxide dismutase, peroxidase, and phenol by 0.07%, 1.86%, 32.66%, 0.08%, 14.63%, and 35.08%, respectively, due to shading stress. Nevertheless, ascorbic acid content in FL was lower (18.90%) compared to FT. Higher fiber diameter (23.53%) and tensile strength (18.77%) of abaca in FT were observed compared to FL. The improved microclimatic conditions under FT promoted the high adaptability of abaca to poor soil quality. Therefore, it contributed to enhanced growth and fiber quality compared to FL. Pruning is pivotal to managing shading intensity.

Abstract Tu140: Evaluation of the effects of mitoquinone on doxorubicin-induced acute cardiac damage

Background: Doxorubicin (DOX)-induced cardiotoxicity remains a high priority to overcome due to irreversibility and lack of abundant preventions. DOX damages the heart tissue principally by overproduction of mitochondrial superoxide and intercalation with the topoisomerase II in the nucleus. Ultimately, cardiac cells become apoptotic, and heart function declines. Our lab has shown that Mitoquinone (MQ), a mitochondria-targeted antioxidant, improves H9c2 cell viability in the presence of DOX. We hypothesize that MQ would counteract DOX to preserve cardiac cells and function in isolated rat hearts, possibly by reducing mitochondrial superoxide production and intracellular accumulation. Methods: H9c2 cells (passages < 18) were incubated with DOX (40 µM) with or without MQ (0.005 μM - 5 μM) for 24 hours before measuring mitochondrial superoxide anion levels and DOX intracellular accumulation. Furthermore, heart rate (HR) and left ventricular end-systolic pressure (LVESP) were recorded before and after a 60-minute infusion of DOX or DOX with MQ in isolated rat hearts. TUNEL staining was performed on heart tissue slides to assess apoptosis. All the data was expressed as a ratio between treatment and DOX alone or between final to initial values. Statistical significance was evaluated using ANOVA with Student Newman Keuls post-hoc analysis. Results: Hearts perfused with DOX (25 µM, n = 5) displayed lower final LVESP with 39 ± 5% of the initial baseline. By contrast, hearts treated with 0.25 µM MQ (n = 4) or 1 µM MQ (n = 5) manifested exhibited a higher final LVESP to 44 ± 8% and 90 ± 6% of initial baselines, respectively. Additionally, MQ administration significantly reduced cardiac cell apoptosis to 8 ± 1% (0.25 µM, n = 2) and 6 ± 1% (1 µM, n = 5, p < 0.05) when compared to DOX (88 ± 2%, n = 4). In contrast to DOX, MQ (1 µM, n = 4) showed 27 ± 9% (n = 4) reduction in mitochondrial superoxide levels and 54 ± 6% (n = 6, p < 0.05) less intracellular DOX deposition in H9c2 cells. Conclusion: This study suggests acute DOX administration to the heart severely compromises cardiac systolic function with higher induction of cell apoptosis. MQ exerts cardio-protection with higher systolic function and cell viability by attenuating mitochondrial superoxide levels and intracellular DOX accumulation.

Interaction of melatonin and H2S mitigates NaCl toxicity summer savory (Satureja hortensis L.) through Modulation of biosynthesis of secondary metabolites and physio-biochemical attributes.

As versatile signaling molecules, melatonin (ML) and hydrogen sulfide (H2S) are well-known for their roles in response to abiotic stresses. However, their cross-talk to the regulation of biochemical defence responses and secondary metabolite synthesis during salinity has received less attention. Here, the role of ML-H2S interplay in inducing defensive responses and the biosynthesis of essential oil compounds in summer savoury plants under NaCl treatment was investigated. NaCl treatment, by increasing Na accumulation, disrupting nitrogen metabolism, and inducing oxidative stress, lowered photosynthetic pigments and savoury growth. NaCl treatment also resulted in a decrease in γ-terpinene (10.3%), α-terpinene (21.9%), and p-cymene (15.3%), while an increase in carvacrol (9.1%) was observed over the control. ML and ML + H2S increased the activity of antioxidant enzymes and the level of total phenols and flavonoids, resulting in decreased levels of hydrogen peroxide and superoxide anion and alleviation of oxidative damage under salinity. ML and ML + H2S increased K uptake and restored K/Na homeostasis, thus protecting the photosynthetic apparatus against NaCl-induced toxicity. ML and ML + H2S treatments also improved nitrate/ammonium homeostasis and stimulated nitrogen metabolism, leading to improved summer savoury adaptation to NaCl stress. ML and ML + H2S changed the composition of essential oils, leading to an increase in the monoterpene hydrocarbons and oxygenated monoterpenes in plants stressed with NaCl. However, the addition of an H2S scavenger, hypotaurine, inhibited the protective effects of the ML and ML + H2S treatments under NaCl stress, which could confirm the function of H2S as a signaling molecule in the downstream defence pathway induced by ML.

Tamarixetin ameliorates cerebral ischemia-reperfusion injury via suppressing nicotinamide adenine dinucleotide phosphate oxidase 2/nucleotide-binding oligomerization domain like receptor family pyrin domain-containing 3 inflammasome activation.

Tamarixetin, a natural dietary flavone, exhibits remarkable potential for the treatment of ischemic stroke. The present article aimed to explore the impact of tamarixetin on ischemic stroke and elucidate the underlying mechanisms. Effects of tamarixetin on ischemic stroke were evaluated in rats using the middle cerebral artery occlusion and reperfusion (MCAO/R) model, by assessing the neurological deficit scores, brain water content, brain infraction, and neuronal damage. The levels of proinflammatory cytokines, NLRP3 inflammasome activation, reactive oxygen species (ROS) production, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression were measured in MCAO/R rats and lipopolysaccharide-stimulated cells. Tamarixetin administration improved the neurological dysfunction and neuronal loss in MCAO/R rats. In addition, tamarixetin reduced microglial hyperactivation and proinflammatory cytokines expression in vivo and in vitro. Tamarixetin attenuated NF-κB p65 phosphorylation and promoter activity, reduced NLRP3 expression and caspase-1 cleavage, and downregulated IL-1β and IL-18 secretions to suppress NLRP3 inflammasome activation. The levels of superoxide anion, hydrogen peroxide, and ROS were also suppressed by tamarixetin. The downregulation of NADP+ and NADPH levels, and gp91phox expression indicated the ameliorative effects of tamarixetin on NADPH oxidase activation. In the gp91phox knockdown cells treated with lipopolysaccharide, the effects of tamarixetin on NADPH oxidase activation, ROS generation, and NLRP3 inflammasome activation were diminished. Moreover, tamarixetin protects neurons against microglial hyperactivation in vitro. Our findings support the potential of tamarixetin as a therapeutic agent for ischemic stroke, and its mechanism of action involves the inhibition of NADPH oxidase-NLRP3 inflammasome signaling.

Exogenous melatonin delays yellowing in harvested broccoli by maintaining chloroplast integrity

Yellowing of broccoli is a crucial limiting factor for its commercial value and consumer acceptance during postharvest. In this study, the impacts of exogenous melatonin (MEL) on chlorophyll content and fluorescence, as well as ultrastructure and membrane lipid metabolism of chloroplasts in broccoli were investigated during postharvest. The results showed that MEL treatment (200 μmol L−1) maintained the chlorophyll content, chloroplast autofluorescence and integral structure, and reduced the level ofserotonin in the chloroplasts in broccoli. Also, MEL treatment inhibited the membrane lipid peroxidation of chloroplasts, as indicated by low levels of superoxide anion (O2-), hydrogen peroxide (H2O2) and malondialdehyde (MDA), and high levels of endogenous MEL. In addition, the stability and fluidity of chloroplast membranes were also better maintained in the treated broccoli via increasing the contents of phosphatidylglyceroland (PG), monogalactosyldiglyceride (MGDG), digalactosyldiglyceride (DGDG) and unsaturated fatty acids as well as decreasing saturated fatty acid content and the activities of lipoxygenase (LOX) and lipase (LPS). Thus, the application of MEL facilitated the maintenance of chloroplast integrity, thus contributing to yellowing postponement and the extension of the storage life of broccoli.

Unraveling the antifungal and anti-aflatoxin B1 mechanisms of piperitone on Aspergillus flavus

Aspergillus flavus infects important crops and produces carcinogenic aflatoxins, posing a serious threat to food safety and human health. Biochemical analysis and RNA-seq were performed to investigate the effects and mechanisms of piperitone on A. flavus growth and aflatoxin B1 biosynthesis. Piperitone significantly inhibited the growth of A. flavus, AFB1 production, and its pathogenicity on peanuts and corn flour. Differentially expressed genes (DEGs) associated with the synthesis of chitin, glucan, and ergosterol were markedly down-regulated, and the ergosterol content was reduced, resulting in a disruption in the integrity of the cell wall and cell membrane. Moreover, antioxidant genes were down-regulated, the correspondingly activities of antioxidant enzymes such as catalase, peroxidase, and superoxide dismutase were reduced, and levels of superoxide anion and hydrogen peroxide were increased, leading to a burst of reactive oxygen species (ROS). Accompanied by ROS accumulation, DNA fragmentation and cell autophagy were observed, and 16 aflatoxin cluster genes were down-regulated. Overall, piperitone disrupts the integrity of the cell wall and cell membrane, triggers the accumulation of ROS, causes DNA fragmentation and cell autophagy, ultimately leading to defective growth and impaired AFB1 biosynthesis.

Untying arsenite tolerance mechanisms in contrasting maize genotypes attributed to NIPs-mediated controlled influx and root-to-shoot translocation, redox homeostasis and phytochelatin-mediated detoxification pathway

Contamination of ground water and soil with toxic metalloids like arsenic (As) poses a serious hazard to the global agricultural food production. One of the best ways to restrict entry of As into the food chain is selection of germplasms which accrue extremely low level of As in grains. Here, we screened diverse maize genotypes under high arsenite (100 μM AsIII) stress and identified PMI-PV-9 and PMI-PV-3 as AsIII-tolerant and -sensitive maize genotype respectively. Expression of genes associated with As uptake, vacuolar sequestration, biosynthesis of phytochelatins, root-to-shoot translocation, in vivo ROS generation, fine tuning of antioxidant defense system, DNA and membrane damage, H2O2 and superoxide anion (O2•-) levels were compared among the selected genotypes. PMI-PV-9 plants performed much better than PMI-PV-3 in terms of plant growth with no visible symptom of As toxicity. Susceptibility of PMI-PV-3 to AsIII stress may be attributed to comparatively low expression of genes involved in phytochelatins (PCs) biosynthesis. Concomitant decrease in ABCC1 expression might be another key factor for futile sequestration of AsIII into root vacuoles. Moreover, up-regulation of ZmNIP3;1 might contribute in high root-to-leaf As translocation. Substantial spike in H2O2, O2•- and MDA levels indicates that PMI-PV-3 plants have experienced more oxidative stress than PMI-PV-9 plants. Appearance of prominent deep brown and dark blue spots/stripes on leaves as revealed after DAB and NBT staining respectively suggest severe oxidative burst in PMI-PV-3 plants. Marked reduction in DHAR and MDAR activity rendered PMI-PV-3 cells to recycle ascorbate pool ineffectively, which might have exacerbated their susceptibility to AsIII stress. In a nutshell, incompetent PCs mediated detoxification system and disruption of cellular redox homeostasis owing to feeble antioxidant defence system resulting oxidative burst might be the prime reasons behind reduced performance of PMI-PV-3 plants under AsIII stress.

Functional Characterization of the Soybean Glycine max Actin Depolymerization Factor GmADF13 for Plant Resistance to Drought Stress.

Abiotic stress significantly affects plant growth and has devastating effects on crop production. Drought stress is one of the main abiotic stressors. Actin is a major component of the cytoskeleton, and actin-depolymerizing factors (ADFs) are conserved actin-binding proteins in eukaryotes that play critical roles in plant responses to various stresses. In this study, we found that GmADF13, an ADF gene from the soybean Glycine max, showed drastic upregulation under drought stress. Subcellular localization experiments in tobacco epidermal cells and tobacco protoplasts showed that GmADF13 was localized in the nucleus and cytoplasm. We characterized its biological function in transgenic Arabidopsis and hairy root composite soybean plants. Arabidopsis plants transformed with GmADF13 displayed a more robust drought tolerance than wild-type plants, including having a higher seed germination rate, longer roots, and healthy leaves under drought conditions. Similarly, GmADF13-overexpressing (OE) soybean plants generated via the Agrobacterium rhizogenes-mediated transformation of the hairy roots showed an improved drought tolerance. Leaves from OE plants showed higher relative water, chlorophyll, and proline contents, had a higher antioxidant enzyme activity, and had decreased malondialdehyde, hydrogen peroxide, and superoxide anion levels compared to those of control plants. Furthermore, under drought stress, GmADF13 OE activated the transcription of several drought-stress-related genes, such as GmbZIP1, GmDREB1A, GmDREB2, GmWRKY13, and GmANK114. Thus, GmADF13 is a positive regulator of the drought stress response, and it may play an essential role in plant growth under drought stress conditions. These results provide new insights into the functional elucidation of soybean ADFs. They may be helpful for breeding new soybean cultivars with a strong drought tolerance and further understanding how ADFs help plants adapt to abiotic stress.

Enhancing Lettuce Drought Tolerance: The Role of Organic Acids in Photosynthesis and Oxidative Defense

The aim of this study was to investigate the effects of maleic acid (MA), salicylic acid (SA), and citric acid (CA) on alleviating the drought stress of a lettuce (Lactuca sativa L.) hydroponic culture. The effect of these organic acids was tested under stress conditions induced by polyethene glycol (PEG 6000) at 5% and 7.5% concentrations. Drought stress reduced the fresh and dry matter yields of plants. The acid treatment caused increasing tendencies in the fresh weight yield:control (SA, MA), PEG 7.5% (SA, MA, CA)) and dry weight yield (control (SA, MA), PEG 5% (MA), PEG 7.5% (SA, MA)). The acid treatment also enhanced the nutrient uptake of stressed plants: SA: N (PEG 7.5%), K (PEG 5 and 7.5%); MA: N, P, K, Ca (PEG 5 and 7.5%). This work found that chlorophyll a and b amounts did not change under applied experimental conditions. Most parameters of chlorophyll fluorescence did not depend on either the level of applied water stress (PEG level) or the type of spraying. Drought stress increased leaf superoxide anion (O2•−) and malondialdehyde (MDA) levels but decreased H2O2. Proline (Pro) and phenolic compounds (TFC), including flavonols (Fla), accumulated more in stressed plants. Drought stress also affected the chlorophyll fluorescence. Our results suggest that acids can improve plant tolerance to drought stress by boosting the antioxidant defence system and reducing the oxidative damage caused by reactive oxygen species.