Reactive Oxygen Species Scavenging Enzymes Research Articles

The allelic mutation of NBS-LRR gene causes premature senescence in wheat.

Premature senescence has a significant impact on the yield and quality of wheat crops. The process is controlled by multiple and intricate genetic pathways and regulatory elements, whereby the discovery of additional mutants provides important insights into the molecular basis of this important trait. Here, we developed a premature senescence wheat mutant je0874, its leaves started to show yellow before heading stage; with plant growth and development, the degree of yellowing worsened rapidly, and chlorophyll content in flag leaf was reduced by 93.8% at 15 days after heading, all other leaves became dryness at the grain filling stage. In the mutant, the reactive oxygen species (ROS) and its metabolites increased up to 34.8%~47.3%, while activities of ROS scavenging enzymes were reduced by 62.7% to 96.7%. Premature senescence resulted in a reduction of thousand grain weight by over 50%. Genetic analysis showed the mutation of senescence was controlled by a single recessive gene, and target gene was finely mapped to a 338kb region of the long arm of chromosome 2D. This region contained a total of 6 annotated genes, while only gene TraesFLD2D01G513900 carried a SNP mutation. The gene contained an NBS-LRR domain, we named it Taps1. Allelic mutants of Taps1 exhibited a lesion mimic phenotype, and the mutant allele resulted in cell death in tobacco, which represent a novel gene controlling wheat senescence. Two haplotypes were identified in 180 accessions, which did not lead to cell death. These results contribute to increase our understanding of the regulation of premature plant senescence.

Effect of energy level on reactive oxygen species metabolism during shade-drying of Thompson seedless grapes and its relation to browning.

The browning of Thompson seedless grapes during shade-drying significantly hampers the sustainable and healthy development of the industry. This study investigates the browning phenomenon and reactive oxygen species (ROS) dynamics when Thompson seedless grapes, treated with adenosine triphosphate (ATP), 2,4-dinitrophenol (DNP), and water (QS), are dried in the shade. The effects of these treatments on ROS metabolism were analyzed through physiological, biochemical, and proteomic analyses. The findings showed that ATP treatment markedly delayed the increase in browning and reactive oxygen content, maintained high activity levels of ROS scavenging enzymes (superoxide dismutase and peroxidase), reduced malondialdehyde production-a membrane lipid peroxidation product-and preserved cell membrane integrity compared to QS and DNP treatments. Proteomic analysis identified three biological pathways involved in ROS metabolism in Thompson seedless grapes: glutathione metabolism, ascorbic acid, and glyoxalate metabolism, and peroxisomal pathways. Exogenous ATP treatment upregulated the expression of 17 proteins (SOD, APX, GPX, GST, GR), with significant increases in GST2 (D7SKQ2), POD1 (F6H095), SOD3 (D7TI74), and SOD4 (F6HTX9) by 1.707, 1.589, 1.644, and 2.213-fold, respectively. Therefore, ATP treatment maintains ROS scavenging proteins' expression, reduces the accumulation of ROS, maintains a balance in ROS metabolism, maintains the cell membrane stability and suppresses the oxidation of lipids, thus delaying the browning of Thompson seedless grapes. These findings are significant for regulating browning in the shade-drying process of Thompson seedless grapes.

α-Tocopherol Long-Chain Metabolite α-T-13'-COOH Exhibits Biphasic Effects on Cell Viability, Induces ROS-Dependent DNA Damage, and Modulates Redox Status in Murine RAW264.7 Macrophages.

The α-tocopherol long-chain metabolite α-tocopherol-13'-hydroxy-chromanol (α-T-13'-COOH) is a proposed regulatory intermediate of endogenous vitamin E metabolism. Effects of α-T-13'-COOH on cell viability and adaptive stress response are not well understood. The present study aims to investigate the concentration-dependent effects of α-T-13'-COOH on cellular redox homeostasis, genotoxicity, and cytotoxicity in murine RAW264.7 macrophages as a model system. Murine RAW264.7 macrophages are exposed to various dosages of α-T-13'-COOH to determine its regulatory effects on reactive oxygen species (ROS) production, DNA damage, expression of stress-related markers, and the activity of ROS scavenging enzymes including superoxide dismutases, catalase, and glutathione-S-transferases. The impact on cell viability is assessed by analyzing cell proliferation, cell cycle arrest, and cell apoptosis. α-T-13'-COOH influences ROS production and induces DNA damage in a dose-dependent manner. The metabolite modulates the activity of ROS-scavenging enzymes, with significant changes observed in the activities of antioxidant enzymes. A biphasic response affecting cell viability is noted: sub-micromolar doses of α-T-13'-COOH promote cell proliferation and enhance DNA synthesis, whereas supraphysiological doses lead to DNA damage and cytotoxicity. It hypothesizes an adaptive stress response, characterized by upregulation of ROS detoxification mechanisms, enhanced cell cycle arrest, and increased apoptosis, indicating a correlation with oxidative stress and subsequent cellular damage.

Exploring the response of yellow lupine (Lupinus luteus L.) root to drought mediated by pathways related to phytohormones, lipid, and redox homeostasis.

Yellow lupine (Lupinus luteus L.) is a high-protein crop of considerable economic and ecological significance. It has the ability to fix atmospheric nitrogen in symbiosis with Rhizobium, enriching marginal soils with this essential nutrient and reducing the need for artificial fertilizers. Additionally, lupine produces seeds with a high protein content, making it valuable for animal feed production. However, drought negatively affects lupine development, its mutualistic relationship with bacteria, and overall yield. To understand how lupine responds to this stress, global transcriptome sequencing was conducted, along with in-depth biochemical, chromatography, and microscopy analyses of roots subjected to drought. The results presented here contribute to strategies aimed at mitigating the effects of water deficit on lupine growth and development. Based on RNA-seq, drought-specific genes were identified and annotated to biological pathways involved in phytohormone biosynthesis/signaling, lipid metabolism, and redox homeostasis. Our findings indicate that drought-induced disruption of redox balance characterized by the upregulation of reactive oxygen species (ROS) scavenging enzymes, coincided with the accumulation of lipid-metabolizing enzymes, such as phospholipase D (PLD) and lipoxygenase (LOX). This disruption also led to modifications in lipid homeostasis, including increased levels of triacylglycerols (TAG) and free fatty acids (FFA), along with a decrease in polar lipid content. Additionally, the stress response involved alterations in the transcriptional regulation of the linolenic acid metabolism network, resulting in changes in the composition of fatty acids containing 18 carbons. The first comprehensive global transcriptomic profiles of lupine roots, combined with the identification of key stress-responsive molecules, represent a significant advancement in understanding lupine's responses to abiotic stress. The increased expression of the Δ12DESATURASE gene and enhanced PLD activity lead to higher level of linoleic acid (18:2), which is subsequently oxidized by LOX, resulting in membrane damage and malondialdehyde (MDA) accumulation. Oxidative stress elevates the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), while the conversion of FFAs into TAGs provides protection against ROS. This research offers valuable molecular and biochemical candidates with significant potential to enhance drought tolerance . It enables innovative strategies in lupine breeding and crop improvement to address critical agricultural challenges.

Transcriptomic and Biochemical Analysis of the Antimicrobial Mechanism of Lipopeptide Iturin W against Staphylococcus aureus.

Staphylococcus aureus is one of the most serious pathogens threatening food safety and public health. We have previously showed that iturin W exhibited obvious antifungal activity on plant pathogens. In the present study, we found iturin W, especially C14 iturin W, showed strong antimicrobial activity against S. aureus, and the antimicrobial mechanism of C14 iturin W was further investigated by transcriptomic analysis and a related biochemical experiment. The results showed that C14 iturin W can reduce the expression levels of genes associated with the reactive oxygen species (ROS) scavenging enzyme and genes involved in arginine biosynthesis, thus leading to the increase in ROS levels of S. aureus. Furthermore, C14 iturin W can also interfere with proton dynamics, which is crucial for cells to regulate various biological possesses. Therefore, ROS accumulation and change in proton motive force are import ways for C14 iturin W to exert the antimicrobial activity. In addition, C14 iturin W can also reduce the expression levels of genes related to virulence factors and decrease the production of enterotoxins and hemolysins in S. aureus, indicating that C14 iturin W has a good potential in food and pharmaceutical fields to reduce the harm caused by S. aureus in the future.

Promoting salt tolerance, growth, and phytochemical responses in coriander (Coriandrum sativum L. cv. Balady) via eco-friendly Bacillus subtilis and cobalt

In plant production, evaluation of salt stress protectants concerning their potential to improve growth and productivity under saline stress is critical. Bacillus subtilis (Bs) and cobalt (Co) have been proposed to optimize salt stress tolerance in coriander (Coriandrum sativum L. cv. Balady) plants by influencing some physiological activities. The main aim of this work is to investigate the response of (Bs) and (Co) as eco-safe salt stress protectants to resist the effect of salinity, on growth, seed, and essential oil yield, and the most important biochemical constituents of coriander produced under salt stress condition. Therefore, in a split-plot factorial experiment design in the RCBD (randomized complete block design), four levels of salinity of NaCl irrigation water (SA) were assigned to the main plots; (0.5, 1.5, 4, and 6 dS m−1); and six salt stress protectants (SP) were randomly assigned to the subplots: distilled water; 15 ppm (Co1); 30 ppm (Co2); (Bs); (Co1 + Bs); (Co2 + Bs). The study concluded that increasing SA significantly reduced coriander growth and yield by 42.6%, which could be attributed to ion toxicity, oxidative stress, or decreased vital element content. From the results, we recommend that applying Bs with Co (30 ppm) was critical for significantly improving overall growth parameters. This was determined by the significant reduction in the activity of reactive oxygen species scavenging enzymes: superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) and non-enzyme: proline by 5, 11.3, 14.7, and 13.8% respectively, while increasing ascorbic acid by 8% and preserving vital nutrient levels and enhancing plant osmotic potential to buffer salt stress, seed yield per plant, and essential oil yield increased by 12.6 and 18.8% respectively. The quality of essential oil was indicated by highly significant quantities of vital biological phytochemicals such as linalool, camphor, and protein which increased by 10.3, 3.6, and 9.39% respectively. Additional research is suggested to determine the precise mechanism of action of Bs and Co's dual impact on medicinal and aromatic plant salt stress tolerance.

Disruption of Poly(ADP-ribosyl)ation Improves Plant Tolerance to Methyl Viologen-Mediated Oxidative Stress via Induction of ROS Scavenging Enzymes.

ADP-ribosylation (ADPRylation) is a mechanism which post-translationally modifies proteins in eukaryotes in order to regulate a broad range of biological processes including programmed cell death, cell signaling, DNA repair, and responses to biotic and abiotic stresses. Poly(ADP-ribosyl) polymerases (PARPs) play a key role in the process of ADPRylation, which modifies target proteins by attaching ADP-ribose molecules. Here, we investigated whether and how PARP1 and PARylation modulate responses of Nicotiana benthamiana plants to methyl viologen (MV)-induced oxidative stress. It was found that the burst of reactive oxygen species (ROS), cell death, and loss of tissue viability invoked by MV in N. benthamiana leaves was significantly delayed by both the RNA silencing of the PARP1 gene and by applying the pharmacological inhibitor 3-aminobenzamide (3AB) to inhibit PARylation activity. This in turn reduced the accumulation of PARylated proteins and significantly increased the gene expression of major ROS scavenging enzymes including SOD (NbMnSOD; mitochondrial manganese SOD), CAT (NbCAT2), GR (NbGR), and APX (NbAPX5), and inhibited cell death. This mechanism may be part of a broader network that regulates plant sensitivity to oxidative stress through various genetically programmed pathways.

Transcriptome Analysis Revealed ZmPTOX1 Is Required for Seedling Development and Stress Tolerance in Maize.

Plant seedling morphogenesis is considerably related to photosynthesis, pigment synthesis, and circadian periodicity during seedling development. We identified and cloned a maize zebra or crossbanding leaves mutant wk3735, which produces pale white kernels and was identified and plays a role in the equilibrium of the Redox state the in/out of ETC by active oxygen scavenging. Interestingly, it produces the zebra leaves during the production of the first seven leaves, which is apparently different from the mutation of homologs AtPTOX in Arabidopsis. It is intriguing to investigate how and why yellow crossbands (zebra leaf phenotype) emerge on leaves. As expected, chlorophyll concentration and photosynthetic efficiency both significantly declined in the yellow sector of wk3735 leaves. Meanwhile, we observed the circadian expression pattern of ZmPTOX1, which was further validated by protein interaction assays of the circadian clock protein TIM1 and ZmPTOX1. The transcriptome data of yellow (muW) and green (muG) sectors of knock-out lines and normal leaves of overexpression lines (OE) at the 5th-leaf seedling stage were analyzed. Zebra leaf etiolated sections exhibit a marked defect in the expression of genes involved in the circadian rhythm and rhythmic stress (light and cold stress) responses than green sections. According to the analysis of co-DEGs of muW vs. OE and muG vs. OE, terms linked to cell repair function were upregulated while those linked to environmental adaptability and stress response were downregulated due to the mutation of ZmPTOX1. Further gene expression level analyses of reactive oxygen species (ROS) scavenging enzymes and detection of ROS deposition indicated that ZmPTOX1 played an essential role in plant stress resistance and ROS homeostasis. The pleiotropic roles of ZmPTOX1 in plant ROS homeostasis maintenance, stress response, and circadian rhythm character may collectively explain the phenotype of zebra leaves during wk3735 seedling development.

Biodegradable Persistent Luminescence Nanoparticles as Pyroptosis Inducer for High-Efficiency Tumor Immunotherapy.

Pyroptosis possesses potent antitumor immune activity, making pyroptosis inducer development a promising direction for tumor immunotherapy. Persistent luminescence nanoparticles (PLNPs) are highly sensitive optical probes extensively employed in tumor diagnosis and therapy. However, a pyroptosis inducer based on PLNPs has not been reported yet. Herein, polyethylene glycol-poly lactic acid-co-glycolic acid (PEG-PLGA: PP) modified biodegradable CaS:Eu2+ (CSE@PP) PLNPs are synthesized as a pyroptosis inducer for tumor immunotherapy for the first time. The synthesized CSE@PP possesses biowindow persistent luminescence (PersL) and pH-responsive degradation properties, allowing it to remain stable under neutral pH but degrade when exposed to weak acid (pH< 6.5). During degradation within the tumor, CSE@PP constantly releases H2S and Ca2+ while its PersL gradually fades away. Thus, the PersL signal can self-monitor H2S and Ca2+ release. Furthermore, the released H2S and Ca2+ result in mitochondrial dysfunction and the inactivation of reactive oxygen species scavenging enzymes, synergistic facilitating intracellular oxidative stress, which induces caspase-1/GSDM-D dependent pyroptosis and subsequent antitumor immune responses. In a word, it is confirmed that CSE@PP can self-monitor H2S and Ca2+ release and pyroptosis-mediated tumor Immunotherapy. This work will facilitate biomedical applications of PLNPs and inspire pyroptosis-induced tumor immunotherapy.

Study on the Function of SlWRKY80 in Tomato Defense against Meloidogyne incognita.

WRKY transcription factors (TFs) can participate in plant biological stress responses and play important roles. SlWRKY80 was found to be differentially expressed in the Mi-1- and Mi-3-resistant tomato lines by RNA-seq and may serve as a key node for disease resistance regulation. This study used RNAi to determine whether SlWRKY80 silencing could influence the sensitivity of 'M82' (mi-1/mi-1)-susceptible lines to M. incognita. Further overexpression of this gene revealed a significant increase in tomato disease resistance, ranging from highly susceptible to susceptible, combined with the identification of growth (plant height, stem diameter, and leaf area) and physiological (soluble sugars and proteins; root activity) indicators, clarifying the role of SlWRKY80 as a positive regulatory factor in tomato defense against M. incognita. Based on this phenomenon, a preliminary exploration of its metabolic signals revealed that SlWRKY80 stimulates different degrees of signaling, such as salicylic acid (SA), jasmonic acid (JA), and ethylene (ETH), and may synergistically regulate reactive oxygen species (ROS) accumulation and scavenging enzyme activity, hindering the formation of feeding sites and ultimately leading to the reduction of root gall growth. To our knowledge, SlWRKY80 has an extremely high utilization value for improving tomato resistance to root-knot nematodes and breeding.

Hierarchical multi-task deep learning-assisted construction of human gut microbiota reactive oxygen species-scavenging enzymes database.

In the process of oxygen reduction, reactive oxygen species (ROS) are generated as intermediates, including superoxide anion (O2-), hydrogen peroxide (H2O2), and hydroxyl radicals (OH-). ROS can be destructive, and an imbalance between oxidants and antioxidants in the body can lead to pathological inflammation. Inappropriate ROS production can cause oxidative damage, disrupting the balance in the body and potentially leading to DNA damage in intestinal epithelial cells and beneficial bacteria. Microorganisms have evolved various enzymes to mitigate the harmful effects of ROS. Accurately predicting the types of ROS-scavenging enzymes (ROSes) is crucial for understanding the oxidative stress mechanisms and formulating strategies to combat diseases related to the "gut-organ axis." Currently, there are no available ROSes databases (DBs). In this study, we propose a systematic workflow comprising three modules and employ a hierarchical multi-task deep learning approach to collect, expand, and explore ROSes-related entries. Based on this, we have developed the human gut microbiota ROSes DB (http://39.101.72.186/), which includes 7,689 entries. This DB provides user-friendly browsing and search features to support various applications. With the assistance of ROSes DB, various communication-based microbial interactions can be explored, further enabling the construction and analysis of the evolutionary and complex networks of ROSes DB in human gut microbiota species.IMPORTANCEReactive oxygen species (ROS) is generated during the process of oxygen reduction, including superoxide anion, hydrogen peroxide, and hydroxyl radicals. ROS can potentially cause damage to cells and DNA, leading to pathological inflammation within the body. Microorganisms have evolved various enzymes to mitigate the harmful effects of ROS, thereby maintaining a balance of microorganisms within the host. The study highlights the current absence of a ROSes DB, emphasizing the crucial importance of accurately predicting the types of ROSes for understanding oxidative stress mechanisms and developing strategies for diseases related to the "gut-organ axis." This research proposes a systematic workflow and employs a multi-task deep learning approach to establish the human gut microbiota ROSes DB. This DB comprises 7,689 entries and serves as a valuable tool for researchers to delve into the role of ROSes in the human gut microbiota.

Exogenous expression of PGC-1α during in vitro maturation impairs the developmental competence of porcine oocytes

Objectives of the current study were to examine the effects of exogenous expression of PGC-1α, which is a transcription factor responsive for controlling mitochondrial DNA (mtDNA) replication, mitochondria quantity control, mitochondrial biogenesis, and reactive oxygen species (ROS) maintenance, in porcine oocytes during in-vitro maturation (IVM) on the developmental competence, as well as mitochondrial quantity and function. Exogenous over-expression of PGC-1α by injection of the mRNA construct into oocytes 20 h after the start of IVM culture significantly increased the copy number of mtDNA in the oocytes, but reduced the incidences of oocytes matured to the metaphase-II stage after the IVM culture for totally 44 h and completely suppressed the early development in vitro to the blastocyst stage following parthenogenetic activation. The exogenous expression of PGC-1α also significantly induced spindle defects and chromosome misalignments. Furthermore, markedly higher ROS levels were observed in the PGC-1α-overexpressed mature oocytes, whereas mRNA level of SOD1, encoded for a ROS scavenging enzyme, was decreased. These results conclude that forced expression of PGC-1α successfully increase mtDNA copy number but led to increased ROS production, evidently by downregulation of SOD1 gene expression, inducement of spindle aberration/chromosomal misalignment, and consequently reduction in the meiotic and developmental competences of porcine oocytes.

Regulation of plum fruit cracking process during cold storage period by treatment of preharvest chitosan

Cracking fruit is a serious quality change phenomenon in the storage and transportation of postharvest plum fruit. To reduce the cracking rate of plum fruit during cold storage, the 'Guofeng No.7′ plum was sprayed with chitosan with 1.5% concentration 30d from preharvest. The postharvest plum fruit was stored at (0 ± 0.5) °C and (85–90) % relative humidity. The results showed that chitosan treatment could reduce the reactive oxygen species (ROS) level of plum fruit, effectively delaying the fruit cracking. Compared with the control, chitosan treated fruits inhibited the increase of free radical content such as O2−· and H2O2 and delayed the increase of membrane permeability and the accumulation of MDA (from 71.9 mmol/g to 53.5 mmol/g). It also regulates lipoxygenase (LOX), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) (enzymatic activity from 34.15 g/min to 42.21 g/min) and ascorbate peroxidase (APX) activity and gene expression during fruit cracking to maintain membrane integrity and intracellular compartmentalization, thereby increasing the crack tolerance of plum fruit during cold storage. These results indicate that preharvest chitosan treatment can inhibit the metabolism of active oxygen species, increase the activity of ROS scavenging enzymes and gene expression, and delay the postharvest cracking of plum fruit.

Selenium Nanoparticles as Neuroprotective Agents: Insights into Molecular Mechanisms for Parkinson's Disease Treatment.

Oxidative stress and the accumulation of misfolded proteins in the brain are the main causes of Parkinson's disease (PD). Several nanoparticles have been used as therapeutics for PD. Despite their therapeutic potential, these nanoparticles induce multiple stresses upon entry. Selenium (Se), an essential nutrient in the human body, helps in DNA formation, stress control, and cell protection from damage and infections. It can also regulate thyroid hormone metabolism, reduce brain damage, boost immunity, and promote reproductive health. Selenium nanoparticles (Se-NPs), a bioactive substance, have been employed as treatments in several disciplines, particularly as antioxidants. Se-NP, whether functionalized or not, can protect mitochondria by enhancing levels of reactive oxygen species (ROS) scavenging enzymes in the brain. They can also promote dopamine synthesis. By inhibiting the aggregation of tau, α-synuclein, and/or Aβ, they can reduce the cellular toxicities. The ability of the blood-brain barrier to absorb Se-NPs which maintain a healthy microenvironment is essential for brain homeostasis. This review focuses on stress-induced neurodegeneration and its critical control using Se-NP. Due to its ability to inhibit cellular stress and the pathophysiologies of PD, Se-NP is a promising neuroprotector with its anti-inflammatory, non-toxic, and antimicrobial properties.

Alleviating chromium-induced oxidative stress in Vigna radiata through exogenous trehalose application: insights into growth, photosynthetic efficiency, mineral nutrient uptake, and reactive oxygen species scavenging enzyme activity enhancement

Trehalose serves as a crucial osmolyte and plays a significant role in stress tolerance. The influence of exogenously added trehalose (1 and 5 mM) in alleviating the chromium (Cr; 0.5 mM) stress-induced decline in growth, photosynthesis, mineral uptake, antioxidant system and nitrate reductase activity in Vigna radiata was studied. Chromium (Cr) significantly declined shoot height (39.33%), shoot fresh weight (35.54%), shoot dry weight (36.79%), total chlorophylls (50.70%), carotenoids (29.96%), photosynthesis (33.97%), net intercellular CO2 (26.86%), transpiration rate (36.77%), the content of N (35.04%), P (35.77%), K (31.33%), S (23.91%), Mg (32.74%), and Ca (29.67%). However, the application of trehalose considerably alleviated the decline. Application of trehalose at both concentrations significantly reduced hydrogen peroxide accumulation, lipid peroxidation and electrolyte leakage, which were increased due to Cr stress. Application of trehalose significantly mitigated the Cr-induced oxidative damage by up-regulating the activity of reactive oxygen species (ROS) scavenging enzymes, including superoxide dismutase (182.03%), catalase (125.40%), ascorbate peroxidase (72.86%), and glutathione reductase (68.39%). Besides this, applied trehalose proved effective in enhancing ascorbate (24.29%) and reducing glutathione content (34.40%). In addition, also alleviated the decline in ascorbate by Cr stress to significant levels. The activity of nitrate reductase enhanced significantly (28.52%) due to trehalose activity and declined due to Cr stress (34.15%). Exogenous application of trehalose significantly improved the content of osmolytes, including proline, glycine betaine, sugars and total phenols under normal and Cr stress conditions. Furthermore, Trehalose significantly increased the content of key mineral elements and alleviated the decline induced by Cr to considerable levels.

Phytic acid-mediated enhancement of Meyerozyma caribbica biocontrol of Aspergillus carbonarius infection in grape berries through regulation of ROS metabolism

Sour rot, an infection caused by Aspergillus carbonarius is one of the detrimental diseases that damage grape vines after harvest. To investigate the biocontrol of this mycotoxigenic fungus, the current study explored the efficiency of Meyerozyma caribbica pretreated with phytic acid (PA) in reducing sour rot in table grapes through the regulation of reactive oxygen species (ROS) production. The content of hydrogen peroxide (H2O2,), superoxide (O2.−) production rate, and the degree of lipid peroxidation were measured. Furthermore, antioxidant enzymes activities, superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and enzymes of the ascorbate–glutathione (AsA-GSH) and glutathione peroxidase (GPX) cycles were investigated. Enzymatic activity results of select genes were confirmed using real-time quantitative polymerase chain reaction (RT-qPCR). Meyerozyma caribbica pretreated with 10 μmol/mL PA (YE) was most efficient in reducing sour decay in grape berries as indicated by an 81.1 % reduction in disease incidence and 1.5 mm lesion diameter by the third day. Phytic acid treated M. caribbica showed a significant reduction in the contents of malondialdehyde (MDA), H2O2, and production rate of O2.− which was complemented by a marked rise in ROS scavenging enzymes’ activities. The H2O2 content in YE was the lowest (24.09 nmol/g FW) by the third day and O2.− production rate was about half that of CK; control (4.19 mmol/min.g FW) on the same day. The SOD, POD, and CAT activities were significantly higher in YE treated fruits (6.63, 18, and 6.64 U/mg FW, respectively) compared to the CK by the fifth day. Subsequently, AsA-GSH and GPX cycles also showed higher activity in grapes inoculated with YE compared to other treatments. Genes encoding SOD, POD, CAT, DHAR, GR, and APX were significantly overexpressed in grapes inoculated with YE compared to the CK, yeast alone, and PA treatments. These findings indicate that PA likely enhances the biocontrol efficacy of M. caribbica, leading to the induction of ROS scavenging mechanisms and subsequent mortality of A. carbonarius in table grapes. Consequently, M. caribbica pre-treated with PA holds promise as a potential biological control agent for A. carbonarius in future applications

Curcumin as a Promising Therapy for COVID-19: A Review

The ongoing COVID-19 pandemic has spurred intense research efforts to identify effective therapeutic options. Among the potential candidates, curcumin, a naturally occurring polyphenol obtained from turmeric, has gained considerable attention due to its diverse pharmacological properties. This review examines the existing literature on curcumin’s potential as a new promising treatment for COVID-19. Curcumin demonstrates antiviral effects by modulating key signaling pathways for entry and multiplication of SARS-CoV-2 in host cells. It limits viral entry in host cells as it binds and inhibits S-protein, TMPRSS2, and ADAM17 enzymes required for cytoadherence and membrane fusion. It also downregulates SARS-CoV-2 replication by preventing the release of the viral genomic RNA into the cytoplasm from virus-containing vacuoles and subsequently inhibits enzymes required for viral replication. Rennin–angiotensin–aldosterone system (RAS) dysfunction, especially increased angiotensin-converting enzyme (ACE)-Angiotensin II-AT1R axis activity, is associated with prothrombotic state, acute respiratory distress syndrome, and lung injury in COVID-19 patients. Curcumin increases soluble ACE2 cellular ACE2 activity, restores RAS normal function, and mitigates these complications. Curcumin also exerts anti-inflammatory and immunomodulatory actions. It reduces the secretion of pro-inflammatory cytokines through inhibition of toll-like receptors (TLRs), namely, TLR2, TLR4, and TLR9, and enhances the production of anti-inflammatory cytokines like interleukin-10. In addition, it prevents the progression of tissue damage and inflammation by reactive oxygen species (ROS) through ROS scavenging enzymes. Due to its antiviral, anti-inflammatory, antioxidant, and immunomodulatory properties, curcumin has emerged as an attractive candidate for combating various aspects of COVID-19 pathogenesis, such as excessive inflammation, oxidative stress, viral multiplication, and immune dysregulation. However, limited clinical evidence is currently available to support its efficacy, specifically against COVID-19. Thus, further research, including clinical trials, is warranted to evaluate curcumin’s therapeutic potential and determine its optimal dosage, formulation, and safety for COVID-19 patients. Overall, based on its favorable pharmacological properties and promising preclinical data, curcumin holds promise as a treatment for COVID-19, but its clinical utility requires further exploration.

Melatonin Mitigates Water Deficit Stress in Cenchrus alopecuroides (L.) Thunb through Up-Regulating Gene Expression Related to the Photosynthetic Rate, Flavonoid Synthesis, and the Assimilatory Sulfate Reduction Pathway.

Melatonin can improve plant adaptability to water deficit stress by regulating the biosynthesis of flavonoids and improving the reactive oxygen species-scavenging enzyme system. However, it remains unclear whether melatonin mitigates the effects and causes of water deficit stress in Cenchrus alopecuroides. We conducted a PEG-simulated water stress pot experiment to determine whether and how exogenous melatonin alleviates water deficit in C. alopecuroides. The experiment was divided into four treatments: (1) normal watering (Control), (2) 40% PEG-6000 treatment (D), (3) 100 μmol·L-1 melatonin treatment (MT), and (4) both melatonin and PEG-6000 treatment (DMT). The results showed that melatonin can alleviate water deficit in C. alopecuroides by effectively inhibiting plant chlorophyll degradation and MDA accumulation while increasing antioxidant enzyme activities and photosynthetic rates under water deficit stress. The transcriptome results indicated that melatonin regulates the expression of genes with the biosynthesis pathway of flavonoids (by increasing the expression of PAL, 4CL, HCT, and CHS), photosynthesis-antenna proteins (by increasing the expression of LHC), and sulfur metabolism (the expression of PAPSS and CysC is up-regulated in the assimilatory sulfate reduction pathway), while up-regulating the transcription factors (AP2/ERF-ERF-, C2H2-, WRKY-, Tify-, bHLH-, NAC-, and MYB-related). These findings revealed the possible causes by which melatonin mitigates water deficit stress in C. alopecuroides, which provided novel insights into the role of melatonin in water deficit stress.

Effects of cold plasma treatment on reactive oxygen metabolism and storage quality of Brassica chinensis

Cold plasma (CP) is a promising non-thermal food preservation technique, which is used for the preservation of fruits and vegetables. In this study, we aimed to determine the effects of CP treatment on the reactive oxygen metabolism, antimicrobial properties, and antioxidant activities in Brassica chinensis during storage at 4 ± 1 °C for 10 days. Postharvest Brassica chinensis were treated with CP for 6 min (CP-6), 9 min (CP-9), and 12 min (CP-12). To maintain a balance between microbial spoilage and storage quality, CP-9 was considered to be the optimal treatment time. Compared with the control group, Brassica chinensis in the CP-9 group showed a 12.7% increased antioxidant capacity, a reduction of the microbial count by 0.7 lg CFU g−1, and a delay in weight loss and soluble solid content reduction. CP inhibited the generation of superoxide anions, improved the activity of reactive oxygen species scavenging enzymes, and delayed the decrease in total antioxidant capacity. Altogether, CP treatment can be considered an advantageous approach to improve the safety and quality of fresh vegetables.

Identification of osmotic stress resistance mediated by MdKAI2 in apple.

KAR (Karrikin), a novel plant growth regulator, can be recognized specifically by plants and can activate resistance responses. MdKAI2 is the natural receptor of KARs in apple. Here, we report the identification of osmotic stress resistance in MdKAI2 via the method of genetic transformation. The phenotypic traits, resistance indicators, and transcriptional and metabolic regulation of MdKAI2 were identified. KAR1, a highly active form of KAR, markedly promoted the root growth of Gala cultivar tissue culture‒generated plants, possibly through increases in ABA and TZR contents and decreases in the GA3 content. MdKAI2 was markedly upregulated by PEG stress and significantly promoted the growth of apple calli under nonstress conditions, whereas it was significantly inhibited under 20% PEG stress, as was cell death. MdKAI2 significantly increased the content of total flavonoids, the activity of reactive oxygen species (ROS)‒scavenging enzymes (SOD, POD and CAT), and the content of osmoregulatory substances (soluble protein, soluble sugars and proline). It also inhibited the MDA content and conductivity under osmotic stress. Differentially expressed genes (DEGs), including multiple transcription factors (TFs), such as MYB, bHLH and AP2‒EREBP, are significantly regulated by MdKAI2, and genes involved in the mitogen‒activated protein kinase (MAPK) signaling pathway play crucial roles in the regulation of plant resistance. In addition, pathways such as brassinosteroid (BR) biosynthesis and ABC transporters were downregulated, and the MAPK signaling pathway; plant‒pathogen interaction; cutin, suberin and wax biosynthesis; alpha‒linolenic acid metabolism; and phenylpropanoid biosynthesis were upregulated by MdKAI2. MdKAI2 significantly regulates the levels of lipids, amino acids, terpenoids, benzene, organic acids, carbohydrates, and alkaloids and is involved in the metabolic processes of amino acids, carbohydrates, nucleotides, lipids and secondary metabolites. Furthermore, MdKAI2 positively regulates fatty acids, esters, and terpenoids and negatively regulates metabolites of amino acids, amides and alcohols, and the MAPK signaling pathway may mediate this process. The study has provided a new direction for the industrial application of KAR1 in apples and resistance breeding based on the gene of MdKAI2.