Reactive Oxygen Species Scavenger Research Articles

AlgU mediates hyperosmotic tolerance in Pseudomonas protegens SN15-2 by regulating membrane stability, ROS scavenging, and osmolyte synthesis.

Pseudomonas protegens can serve as an agricultural biocontrol agent. P. protegens often encounters hyperosmotic stress during industrial production and field application. The ability of P. protegens to withstand hyperosmotic stress is important for its application as a biocontrol agent. AlgU is a global regulator responsible for stress response and biocontrol ability. However, the specific regulatory role of AlgU in the hyperosmotic adaptation of P. protegens is poorly understood. In this study, we found that the AlgU mutation disrupted the hyperosmotic tolerance of P. protegens. Many genes and metabolites related to cell envelope formation were significantly downregulated in ΔalgU compared with that in the wild-type (WT) strain under hyperosmotic conditions, and we found that the algU mutation caused membrane integrity to be compromised and increased membrane permeability. Further experiments revealed that the cell envelope integrity protein TolA, which is regulated by AlgU, contributes to cell membrane stability and osmotic tolerance in P. protegens. In addition, several genes related to oxidative stress response were significantly downregulated in ΔalgU, and higher levels of intracellular reactive oxygen species were found in ΔalgU. Furthermore, we found that the synthesis of N-acetyl glutaminyl glutamine amide is directly regulated by AlgU and contributes to the hyperosmotic adaptation of P. protegens. This study revealed the mechanisms of AlgU's participation in osmotic tolerance in P. protegens, and it provides potential molecular targets for research on the hyperosmotic adaptation of P. protegens.IMPORTANCEIn this study, we found that the extracytoplasmic function sigma factor AlgU is essential for the survival of P. protegens under hyperosmotic conditions. We provided evidence supporting the roles of AlgU in influencing cell membrane stability, intracellular reactive oxygen species (ROS) accumulation, and dipeptide N-acetylglutaminylglutamine amide (NAGGN) synthesis in P. protegens under hyperosmotic conditions. Our findings revealed the mechanisms of AlgU's participation in hyperosmotic stress tolerance in P. protegens, and they provide potential molecular targets for research on the hyperosmotic adaptation of P. protegens, which is of value in improving the biocontrol ability of P. protegens.

Real-time monitoring of cellular superoxide anion release in THP-1 cells using a catalytically amplified superoxide dismutase-based microbiosensor.

Reactive oxygen species (ROS) including the superoxide anion (O2•-) are typically studied in cell cultures using fluorescent dyes, which provide only discrete single-point measurements. These methods lack the capabilities for assessing O2•- kinetics and release in a quantitative manner over long monitoring times. Herein, we present the fabrication and application of an electrochemical biosensor that enables real-time continuous monitoring of O2•- release in cell cultures for extended periods (> 8h) using an O2•- specific microelectrode. To achieve the sensitivity and selectivity requirements for cellular sensing, we developed a biohybrid system consisting of superoxide dismutase (SOD) and Ti3C2Tx MXenes, deposited on a gold microwire electrode (AuME) as O2•- specific materials with catalytic amplification through the synergistic action of the enzyme and the biomimetic MXenes-based structure. The biosensor demonstrated a sensitivity of 18.35 nA/μM with a linear range from 147 to 930nM in a cell culture medium. To demonstrate its robustness and practicality, we applied the biosensor to monitor O2•- levels in human leukemia monocytic THP-1 cells upon stimulation with lipopolysaccharide (LPS). Using this strategy, we successfully monitored LPS-induced O2•- in THP-1 cells, as well as the quenching effect induced by the ROS scavenger N-acetyl-L-cysteine (NAC). The biosensor is generally useful for exploring the role of oxidative stress and longitudinally monitoring O2•- release in cell cultures, enabling studies of biochemical processes and associated oxidative stress mechanisms in cellular and other biological environments.

The photosynthetic performance and photoprotective role of carotenoids response to light stress in intertidal red algae Neoporphyra haitanensis.

Neoporphyra haitanensis, a red alga harvested for food, thrives in the intertidal zone amid dynamic and harsh environments. High irradiance represents a major stressor in this habitat, posing a threat to the alga's photosynthetic apparatus. Interestingly, N. haitanensis has adapted to excessive light despite the absence of a crucial xanthophyll cycle-dependent photoprotection pathway. Thus, it is valuable to investigate the mechanisms by which N. haitanensis copes with excessive light and to understand the photoprotective roles of carotenoids. Under high light intensities and prolonged irradiation time, N. haitanensis displayed reduction in photosynthetic efficiency and phycobiliproteins levels, as well as different responses in carotenoids. The decreased carotene contents suggested their involvement in the synthesis of xanthophylls, as evidenced by the up-regulation of lycopene-β-cyclase (lcyb) and zeaxanthin epoxidase (zep) genes. Downstream xanthophylls such as lutein, zeaxanthin, and antheraxanthin increased proportionally to light stress, potentially participating in scavenging reactive oxygen species (ROS). When accompanied by the enhanced activity of ascorbate peroxidase (APX), these factors resulted in a reduction in ROS production. The responses of intermediates α-cryptoxanthin and β-cryptoxanthin were felt somewhere between carotenes and zeaxanthin/lutein. Furthermore, these changes were ameliorated when the organism was placed in darkness. In summary, down-regulation of the organism's photosynthetic capacity, coupled with heightened xanthophylls and APX activity, activates photoinhibition quenching (qI) and antioxidant activity, helping N. haitanensis to protect the organism from the damaging effects of excessive light exposure. These findings provide insights into how red algae adapt to intertidal lifestyles.

A novel metal‐organic framework encapsulated iridium oxide nanozyme enhanced antisense oligonucleotide combo for osteoarthritis synergistic therapy

AbstractOsteoarthritis (OA) is associated with metabolic imbalance of articular cartilage and an increase of intracellular reactive oxygen species (ROS). Synergistic therapy based on the codelivery of ROS scavengers and antisense oligonucleotides (ASO) into chondrocytes has the potential to effectively treat OA. Here, we developed a novel biocompatible metal‐organic framework (MOF)‐encapsulated nanozyme/ASO delivery platform (miR/IrO2@ZIF‐8) for OA treatment. IrO2 nanoparticles with the catalytic activities of superoxide dismutase/catalase were synthesized using a hydrothermal method, resulting in excellent ROS scavenging performance. IrO2 was further loaded into zeolitic imidazolate framework‐8 (ZIF‐8) to maintain its catalytic efficacy and regulate its size, surface charge, and biocompatibility to enhance the therapeutic effect of the platform. As an effective ASO delivery carrier, the synthesized IrO2@ZIF‐8 exhibited high antagomiR‐181a loading and lysosomal escape capacity, enabling it to rebalance cartilage metabolism. In vitro experiments showed that miR/IrO2@ZIF‐8 could restore ROS levels, mitochondrial membrane potential, and lipid peroxidation in chondrocytes. At the same time, the expression levels of proinflammatory markers (IL‐1β, IL‐6, and COX‐2) as well as the extracellular matrix degrading enzymes (ADAMTS‐5 and MMP13) were downregulated, indicating effective antioxidant, anti‐inflammatory, and anticartilage degradation effects. Notably, miR/IrO2@ZIF‐8 was able to deliver IrO2 nanoparticles and antagomiR‐181a to the cartilage tissue at a depth of up to 1.5 mm, thus solving the problems of poor permeability and difficult retention of drugs in cartilage tissue. This further improves the synergistic therapeutic effect on OA by inhibiting cartilage degradation. The combination of MOF‐encapsulated IrO2 nanozymes with antagomiR‐181a has an excellent therapeutic effect on OA, offering a promising translational medicine paradigm.

Sunlight-mediated removal of endocrine disruptors from wastewater using trimetallic core-shell Ag-TeO2@ZnO nanocomposites

The current work emphasizes the preparation of trimetallic core-shell Ag–TeO2@ZnO nanocomposites (NCs) by thermo-mechanical method for the efficient photocatalytic degradation of 2,4-Dichlorophenol and β-naphthol pollutants. FE-SEM shows that Ag and TeO2 nanoparticles are deposited on the surface of ZnO nanotubes. The band gap of pristine ZnO NPs and 5 wt% Ag–TeO2@ZnO nanocomposites are found to be 3.16 and 2.96 eV, respectively. The calculated specific surface area (SBET) of pristine ZnO NPs and 5 wt% Ag–TeO2@ZnO nanocomposites are 40.47 and 45.66 m2 g−1 respectively, confirming that Ag and TeO2 nanoparticles contribute to increasing in surface area of pure ZnO. The synthesised nanocomposite showed excellent photocatalytic performance for the degradation of β -naphthol (95.6%) in 40 min at the concentration of (0.6 mg ml−1) and 2,4-DCP (99.6%) in 180 min (0.4 mg ml−1) under natural sunlight. Cyclic Voltammetry and Electrochemical Impedance Spectroscopy were carried out to study the electrochemical properties. The determination of reactive oxygen species (ROS) confirmed that the degradation of the pollutants by 5 wt% Ag–TeO2@ZnO NCs was due to the formation of superoxide radicals. Electron paramagnetic resonance revealed the presence of sharp signals in pure ZnO nanoparticles at g ∼1.95 and oxygen vacancy peak at g ∼2.01 in 5 wt% Ag–TeO2@ZnO NCs. To study the mechanism behind the degradation of pollutants, Scavenger test using histidine and ascorbic acid (ROS scavengers) was performed. The synthesised nanocomposites are highly stable and showed enhanced efficiency up to three cycles, confirming their reusability as a photocatalyst.

Highly Compressible, Superabsorbent, and Biocompatible Hybrid Cryogel Constructs Comprising Functionalized Chitosan and St. John's Wort Extract.

Biobased porous hydrogels enriched with phytocompounds-rich herbal extracts have aroused great interest in recent years, especially in healthcare. In this study, new macroporous hybrid cryogel constructs comprising thiourea-containing chitosan (CSTU) derivative and a Hypericum perforatum L. extract (HYPE), commonly known as St John's wort, were prepared by a facile one-pot ice-templating strategy. Benefiting from the strong interactions between the functional groups of the CSTU matrix and those of polyphenols in HYPE, the hybrid cryogels possess excellent liquid absorption capacity, mechanical resilience, antioxidant performance, and a broad spectrum of antibacterial activity simultaneously. Thus, owing to their design, the hybrid constructs exhibit an interconnected porous architecture with the ability to absorb over 33 and 136 times their dry weight, respectively, when contacted with a phosphate buffer solution (pH 7.4) and an acidic aqueous solution (pH 2). These cryogel constructs have extremely high compressive strengths ranging from 839 to 1045 kPa and withstand elevated strains of over 70% without developing fractures. Moreover, the water-swollen hybrid cryogels with the highest HYPE content revealed a complete and instant shape recovery after uniaxial compression. The incorporation of HYPE into CSTU cryogels enabled substantial improvement in scavenging reactive oxygen species and an expanded antibacterial spectrum toward multiple pathogens, including Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and fungi (Candida albicans). Cell viability experiments demonstrated the cytocompatibility of the 3D cryogel constructs, which did not induce changes in the fibroblast morphology. This work showcases a simple and effective strategy to immobilize HYPE extracts on CSTU 3D networks, allowing the development of novel multifunctional platforms with promising potential in hemostasis, wound dressing, and dermal regeneration scaffolds.

The role of reactive oxygen species in regulation of the plasma membrane H +-ATPase activity in Masson pine (Pinus massoniana Lamb.) roots responding to acid stress.

To understand the role of reactive oxygen species (ROS) in regulation of the plasma membrane (PM) H+-ATPase in acid-stressed Masson pine roots, different acidity (pH6.6 as the control, pH5.6, and pH4.6) of simulated acid rain (SAR) added with and without external chemicals [H2O2, enzyme inhibitors, and ROS scavenger] was prepared. After 30days of SAR exposure, the plant morphological phenotype attributes, levels of cellular ROS and lipid peroxidation, enzymatic activities of antioxidants, PM nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and PM H+-ATPase activity in pine seedlings were measured. Compared to the control, the growth of pine seedlings exposed to SAR in the presence or absence of H2O2 was well-maintained, but the application of Na3VO4, 1,3-Dimethyl-2-thiourea, N, N-dimethylthiourea (DMTU), and diphenyleneiodonium chloride (DPI) caused a substantial growth inhibition. In addition, SAR exposure, SAR with H2O2 treatment, and SAR with Na3VO4 treatment increased the cellular H2O2 content, O2·- content, and malondialdehyde (MDA) content, while the use of DMTU and DPI lead to relatively low levels. Similarly, the enzymatic activities of antioxidants, PM NADPH oxidase, and PM H+-ATPase in acid stressed pine seedlings elevated with the increasing acidity. A significant stimulation of these enzymatic activities obtained from SAR with H2O2 treatment was observed, whereas which decreased obviously with the addition of Na3VO4, DMTU, and DPI (P<0.05). Moreover, a positive correlation was found between plant morphological attributes and the PM H+-ATPase activity (P<0.05). Besides, the PM H+-ATPase activity positively correlated with the cellular ROS contents and the enzymatic activities of antioxidants and PM NADPH oxidase (P<0.05). Therefore, the PM H+-ATPase is instrumental in the growth of pine seedlings resisting to acid stress by enhancing its activity. The process involves the signaling transduction of cellular ROS and coordination with PM NADPH oxidase.

Metallothionein: A Comprehensive Review of Its Classification, Structure, Biological Functions, and Applications

Metallothionein is a cysteine-rich protein with a high metal content that is widely found in nature. In addition to heavy metal detoxification, metallothionein is well known as a potent antioxidant. The high sulfhydryl content of metallothionein confers excellent antioxidant activity, enabling it to effectively scavenge free radicals and mitigate oxidative stress damage. In addition, metallothionein can play a neuroprotective role by alleviating oxidative damage in nerve cells, have an anticancer effect by enhancing the ability of normal cells to resist unfavorable conditions through its antioxidant function, and reduce inflammation by scavenging reactive oxygen species. Due to its diverse biological functions, metallothionein has a broad potential for application in alleviating environmental heavy metal pollution, predicting and diagnosing diseases, and developing skin care products and health foods. This review summarizes the recent advances in the classification, structure, biological functions, and applications of metallothionein, focusing on its powerful antioxidant effects and related functions.

PoWRKY69-PoVQ11 module positively regulates drought tolerance by accumulating fructose in Paeonia ostii.

Drought is a detrimental environmental factor that restricts plant growth and threatens food security throughout the world. WRKY transcription factors play vital roles in abiotic stress response. However, the roles of IIe subgroup members from WRKY transcription factor family in soluble sugar mediated drought response are largely elusive. In this study, we identified a drought-responsive IIe subgroup WRKY transcription factor, PoWRKY69, from Paeonia ostii. PoWRKY69 functioned as a positive regulator in response to drought stress with nucleus expression and transcriptional activation activity. Silencing of PoWRKY69 increased plants sensitivity to drought stress, whereas conversely, overexpression of PoWRKY69 enhanced drought tolerance in plants. As revealed by yeast one-hybrid, electrophoretic mobility shift assay, and luciferase reporter assays, PoWRKY69 could directly bind to the W-box element of fructose-1,6-bisphosphate aldolase 5 (PoFBA5) promoter, contributing to a cascade regulatory network to activate PoFBA5 expression. Furthermore, virus-induced gene silencing and overexpression assays demonstrated that PoFBA5 functioned positively in response to drought stress by accumulating fructose to alleviate membrane lipid peroxidation and activate antioxidant defense system, these changes resulted in reactive oxygen species scavenging. According to yeast two-hybrid, bimolecular fluorescence complementation, and firefly luciferase complementation imaging assays, valine-glutamine 11 (PoVQ11) physically interacted with PoWRKY69 and led to an enhanced activation of PoWRKY69 on PoFBA5 promoter activity. This study broadens our understanding of WRKY69-VQ11 module regulated fructose accumulation in response to drought stress and provides feasible molecular measures to create novel drought-tolerant germplasm of P. ostii.

GLUTAMYL-tRNA SYNTHETASE 1 deficiency confers thermo-sensitive male sterility in rice by affecting ROS homeostasis.

Temperature is one of the key environmental factors influencing crop fertility and yield. Understanding how plants sense and respond to temperature changes is, therefore, crucial for improving agricultural production. In this study, we characterized a temperature-sensitive male-sterile mutant in rice (Oryza sativa), glutamyl-tRNA synthetase 1-2 (ers1-2), that shows reduced fertility at high temperatures and restored fertility at low temperatures. Mutation of ERS1 resulted in severely delayed pollen development and meiotic progression at high temperatures, eventually leading to male sterility. Moreover, meiosis-specific events, including synapsis and crossover formation, were also delayed in ers1-2 compared with the wild type. However, these defects were all mitigated by growing ers1-2 at low temperatures. Transcriptome analysis and measurement of ascorbate, glutathione, and hydrogen peroxide (H2O2) contents revealed that the delayed meiotic progression and male sterility in ers1-2 were strongly associated with changes in reactive oxygen species (ROS) homeostasis. At high temperatures, ers1-2 exhibited decreased accumulation of ROS scavengers and overaccumulation of ROS. In contrast, at low temperatures, the antioxidant system of ROS was more active, and ROS contents were lower. These data suggest that ROS homeostasis in ers1-2 is disrupted at high temperatures but restored at low temperatures. We speculate that ERS1 dysfunction leads to changes in ROS homeostasis under different conditions, resulting in delayed or rescued meiotic progression and thermosensitive male fertility. ers1-2 may hold great potential as a thermosensitive material for crop heterosis breeding.

Genome-wide analysis of R2R3-MYB transcription factors in poplar and functional validation of PagMYB147 in defense against Melampsora magnusiana

Main conclusionTranscription of PagMYB147 was induced in poplar infected by Melampsora magnusiana, and a decline in its expression levels increases the host's susceptibility, whereas its overexpression promotes resistance to rust disease.Poplars are valuable tree species with diverse industrial and silvicultural applications. The R2R3-MYB subfamily of transcription factors plays a crucial role in response to biotic stresses. However, the functional studies on poplar R2R3-MYB genes in resistance to leaf rust disease are still insufficient. We identified 191 putative R2R3-MYB genes in the Populus trichocarpa genome. A phylogenetic analysis grouped poplar R2R3-MYBs and Arabidopsis R2R3-MYBs into 33 subgroups. We detected 12 tandem duplication events and 148 segmental duplication events, with the latter likely being the main contributor to the expansion of poplar R2R3-MYB genes. The promoter regions of these genes contained numerous cis-acting regulatory elements associated with response to stress and phytohormones. Analyses of RNA-Seq data identified a multiple R2R3-MYB genes response to Melampsora magnusiana (Mmag). Among them, PagMYB147 was significantly up-regulated under Mmag inoculation, salicylic acid (SA) and methyl jasmonate (MeJA) treatment, and its encoded product was primarily localized to the cell nucleus. Silencing of PagMYB147 exacerbated the severity of Mmag infection, likely because of decreased reactive oxygen species (ROS) production and phenylalanine ammonia-lyase (PAL) enzyme activity, and up-regulation of genes related to ROS scavenging and down-regulation of genes related to PAL, SA and JA signaling pathway. In contrast, plants overexpressing PagMYB147 showed the opposite ROS accumulation, PAL enzyme activity, SA and JA-related gene expressions, and improved Mmag resistance. Our findings suggest that PagMYB147 acts as a positive regulatory factor, affecting resistance in poplar to Mmag by its involvement in the regulation of ROS homeostasis, SA and JA signaling pathway.

Altered S-AdenosylMethionine availability impacts dNTP pools in Saccharomyces cerevisiae.

Saccharomyces cerevisiae has long been used as a model organism to study genome instability. The SAM1 and SAM2 genes encode AdoMet synthetases, which generate S-AdenosylMethionine (AdoMet) from Methionine (Met) and ATP. Previous work from our group has shown that deletions of the SAM1 and SAM2 genes cause changes to AdoMet levels and impact genome instability in opposite manners. AdoMet is a key product of methionine metabolism and the major methyl donor for methylation events of proteins, RNAs, small molecules, and lipids. The methyl cycle is interrelated to the folate cycle which is involved in de novo synthesis of purine and pyrimidine deoxyribonucleotides (dATP, dTTP, dCTP, and dGTP). AdoMet also plays a role in polyamine production, essential for cell growth and used in detoxification of reactive oxygen species (ROS) and maintenance of the redox status in cells. This is also impacted by the methyl cycle's role in production of glutathione, another ROS scavenger and cellular protectant. We show here that sam2∆/sam2∆ cells, previously characterized with lower levels of AdoMet and higher genome instability, have a higher level of each dNTP (except dTTP), contributing to a higher overall dNTP pool level when compared to wildtype. Unchecked, these increased levels can lead to multiple types of DNA damage which could account for the genome instability increases in these cells.

P-024 Revitalizing male fertility: Crocin’s dual role in antioxidant mastery and mitochondrial activation to enhance sperm motility

Abstract Study question The study aims to investigate the potential effect of crocin, a major constituent of Crocus sativus (saffron), on improving sperm motility in patients with asthenozoospermia. Summary answer In vitro crocin treatment enhances sperm motility, reduces ROS, improves mitochondrial membrane potential, and boosts mitochondrial activity, suggesting the potential role of enhancing sperm motility. What is known already Male infertility can result from various factors, with excessive production of reactive oxygen species (ROS) adversely affecting sperm motility. Crocin, known for its antioxidant properties in scavenging ROS, has led to increasing interest in natural compounds to enhance sperm quality. Study design, size, duration The current study involved the evaluation of 95 patients at the Service of Reproductive Biology at the Maternity and Neonatology Center of Monastir. Sperm samples were collected and incubated for 3 hours at 37 °C with increasing concentrations of Crocin (0, 0.2, 0.5, 1, 1.5 mM). Participants/materials, setting, methods This study included asthenozoospermic patients, categorized into two groups: G1 with progressive motility (PM) between 20% and 30%, and G2 with PM between 10% and 15%. Sperm samples underwent treatment with Crocin. Evaluation encompassed sperm motility, considering the distance covered and velocity via video-microscopy. Additionally, intracellular ROS levels were assessed using DCFH-DA fluorochrome, mitochondrial membrane potential was measured with rh123, and mitochondrial activity was determined through succinate dehydrogenase activity via the MTT assay. Main results and the role of chance The results demonstrate that sperm motility is significantly enhanced after in vitro treatment with 1mM Crocin for 3 hours, with 1.9-fold (p &amp;lt; 0.001) and 1.7-fold (p &amp;lt; 0.001) increases in sperm velocity and distance traveled, respectively. Additionally, Crocin reduces intracellular ROS levels, exhibiting a reduction of 1.5-fold (p &amp;lt; 0.001) in G1 and 2.4-fold (p &amp;lt; 0.001) in G2. Fluorescence microscopy of spermatozoa from a patient with severe asthenozoospermia showed intense ROS-induced fluorescence, which was attenuated after incubation with 1 mM Crocin for 3 hours. Furthermore, Crocin demonstrates a noteworthy improvement in mitochondrial membrane potential, with 1.7-fold (p &amp;lt; 0.001) for G1 and 1.9-fold (p &amp;lt; 0.001) for G2, suggesting its capability to prevent the decline of mitochondrial potential. Microscopic fluorescence revealed a marked increase in fluorescence, particularly in the midpiece after Crocin treatment, confirming the protective effect of Crocin on mitochondrial membrane potential. Moreover, there is a substantial increase in mitochondrial activity with Crocin, particularly in G1, showing a 2.14-fold (p &amp;lt; 0.001) increase compared to the G2 group’s 1.85-fold (p &amp;lt; 0.001) increase. These findings collectively highlight the multifaceted benefits of Crocin, encompassing enhanced sperm motility, reduced ROS levels, preserved mitochondrial membrane potential, and heightened mitochondrial activity, underscoring its potential as a therapeutic agent for male infertility, particularly in cases of asthenozoospermia. Limitations, reasons for caution While promising, this study’s limitations include the in vitro treatment, and not fully replicating complex in vivo conditions. Focused on asthenozoospermia, generalizing findings to other male infertility forms necessitates further investigation. Validation of Crocin’s therapeutic potential in male infertility requires additional clinical trials. Wider implications of the findings Our findings suggest that in vitro enhancement of sperm quality with crocin may serve as a promising solution to improve assisted reproductive techniques, mitigating exogenous oxidative stress during laboratory procedures. This insight holds potential for advancing reproductive interventions and warrants further exploration in clinical settings. Trial registration number not applicable

Integrative proteome and metabolome unveil the central role of IAA alteration in axillary bud development following topping in tobacco

Axillary bud is an important aspect of plant morphology, contributing to the final tobacco yield. However, the mechanisms of axillary bud development in tobacco remain largely unknown. To investigate this aspect of tobacco biology, the metabolome and proteome of the axillary buds before and after topping were compared. A total of 569 metabolites were differentially abundant before and 1, 3, and 5 days after topping. KEGG analyses further revealed that the axillary bud was characterized by a striking enrichment of metabolites involved in flavonoid metabolism, suggesting a strong flavonoid biosynthesis activity in the tobacco axillary bud after topping. Additionally, 9035 differentially expressed proteins (DEPs) were identified before and 1, 3, and 5 days after topping. Subsequent GO and KEGG analyses revealed that the DEPs in the axillary bud were enriched in oxidative stress, hormone signal transduction, MAPK signaling pathway, and starch and sucrose metabolism. The integrated proteome and metabolome analysis revealed that the indole-3-acetic acid (IAA) alteration in buds control dormancy release and sustained growth of axillary bud by regulating proteins involved in carbohydrate metabolism, amino acid metabolism, and lipid metabolism. Notably, the proteins related to reactive oxygen species (ROS) scavenging and flavonoid biosynthesis were strongly negatively correlated with IAA content. These findings shed light on a critical role of IAA alteration in regulating axillary bud outgrowth, and implied a potential crosstalk among IAA alteration, ROS homeostasis, and flavonoid biosynthesis in tobacco axillary bud under topping stress, which could improve our understanding of the IAA alteration in axillary bud as an important regulator of axillary bud development.

Visualizing detection of cysteine level under LPS-induced oxidative stress process using benzopyrylium-based mitochondrial-targeted NIR fluorescent probe

As an important scavenger of reactive oxygen species, cysteine (Cys) plays a crucial role in mitochondrial oxidative stress. Abnormal intracellular Cys concentration under oxidative stress leads to various diseases. Cys is also widely used in the food industry. Many vegetables and fruits are rich in Cys. Abnormal levels of Cys in the body can lead to a variety of diseases. Therefore, the design of fluorescent probe that can detect Cys quickly is particularly important in living organisms. In this work, a novel turn-on mitochondrial-targeted NIR fluorescent probe (SXNU-6) was designed for the high sensitivity and specificity of Cys based on benzopyrylium. Among them, acrylate group acted as recognition site and fluorescence quencher. With the addition of Cys, the fluorescence of SXNU-6 was gradually enhanced at 660 nm. The probe had good selectivity and high sensitivity, which could realize the detection of Cys in food samples (onion, garlic, tomato, lettuce, apple, pear, milk and bread). Also, SXNU-6 could detect both endogenous and exogenous Cys under LPS-induced oxidative stress process. This work provide a powerful tool for detecting Cys in food samples and biological systems.

Self-assembled copper herbal carbon dots nanosheets with powerful antibacterial properties: A robust cascade antioxidant nanozyme for scavenging reactive oxygen species

Oxidative stress is a growing concern, necessitating more effective antioxidants for complex environments. Herein, we developed a composite nanozyme, DVI-CDs-Cu, with exceptional antioxidant and antibacterial properties by utilizing DVI-CDs derived from Chinese herbs: Dandelion, Violet, and Isatis root, complexed with Cu2+ ions. The DVI-CDs with abundant surface functional groups exhibited excellent superoxide dismutase-like (SOD-like) activity while forming stable complexes with copper ions. The attached copper ions performed the peroxidase-like (POD-like) function and formed a cascade effect, greatly enhancing the antioxidant capacity of the DVI-CDs-Cu nanozyme and strengthening its antibacterial property. The nanozyme was able to comprehensively clear 90 % of reactive oxygen species (ROS) while killing approximately 98 % of bacteria. The potential application of the nanozyme as a ROS scavenger was demonstrated by exploring its application to cigarette filters, capable of eliminating approximately 80 % of ROS. This provides a new case for the design and development of CDs-metal ions synergistic bionano-enzymes.

Slightly acidic electrolyzed water treatment enhances the quality attributes and the storability of postharvest litchis through regulating the metabolism of reactive oxygen species

Effects of slightly acidic electrolyzed water (SAEW) on the storability, quality attributes, and reactive oxygen species (ROS) metabolism of litchis were investigated. Results showed that SAEW-treated litchis presented better quality attributes and storability than control litchis. On storage day 5, the commercially acceptable fruit rate of control litchis was 42%, while SAEW-treated litchis displayed 59% higher rate of commercially acceptable fruit, 21% lower pericarp browning index, and 13% lower weight loss percentage than control litchis. Additionally, compared to control litchis, SAEW-treated litchis demonstrated higher activities of SOD, CAT and APX, higher levels of GSH, AsA, DPPH radical scavenging ability, and reducing power, but lower O2−· generation rate, lower levels of H2O2 and MDA. These findings indicated that SAEW treatment could elevate antioxidant capacity and ROS scavenging ability, reduce ROS production and accumulation, and lower membrane lipid peroxidation, thereby retaining the quality attributes and storability of litchis.

Transcriptomic Analysis Reveals Dynamic Changes in Glutathione and Ascorbic Acid Content in Mango Pulp across Growth and Development Stages

Mango (Mangifera indica) is a highly valuable horticultural crop known for its quality and productivity. This study investigates the dynamic changes in physicochemical properties and glutathione and ascorbic acid metabolic pathways in mango pulp across various growth and development stages over two consecutive years (2021–2022 and 2022–2023) by transcriptomic analysis. Overall, the results demonstrate that during different ripening periods, the pulp shows increased levels of total soluble solids, relative conductivity, glutathione, and enzymes, while titratable acidity, malondialdehyde, reactive oxygen species, and ascorbic acid contents decreased. Moreover, transcriptomic analysis identified key differentially expressed genes from the glutathione and ascorbic acid metabolic pathways and validated them with qRT-PCR. In different comparisons, a total of 1776, 2513, and 828 DEGs were identified in 30 vs. 60, 30 vs. 90, and 60 vs. 90 days after flowering, respectively. Among them, seven DEGs were primarily enriched in relevant pathways, which included ascorbate peroxidase, ascorbate oxidase, glutathione peroxidase, gamma-glutamyl transferase, glutathione transferases, and glucose-6-phosphate dehydrogenase. The upregulation of these genes indicates that glutathione and AsA respond well to scavenging reactive oxygen species and maintain normal functioning in plants. This research sheds light on the molecular mechanisms of glutathione and ascorbic acid dynamic changes in mango pulp, providing valuable insights into the regulation of antioxidant and metabolic pathways during fruit growth and development.

Populus euphratica CPK21 Interacts with NF-YC3 to Enhance Cadmium Tolerance in Arabidopsis.

The toxic metal cadmium (Cd) poses a serious threat to plant growth and human health. Populus euphratica calcium-dependent protein kinase 21 (CPK21) has previously been shown to attenuate Cd toxicity by reducing Cd accumulation, enhancing antioxidant defense and improving water balance in transgenic Arabidopsis. Here, we confirmed a protein-protein interaction between PeCPK21 and Arabidopsis nuclear transcription factor YC3 (AtNF-YC3) by yeast two-hybrid and bimolecular fluorescence complementation assays. AtNF-YC3 was induced by Cd and strongly expressed in PeCPK21-overexpressed plants. Overexpression of AtNF-YC3 in Arabidopsis reduced the Cd inhibition of root length, fresh weight and membrane stability under Cd stress conditions (100 µM, 7 d), suggesting that AtNF-YC3 appears to contribute to the improvement of Cd stress tolerance. AtNF-YC3 improved Cd tolerance by limiting Cd uptake and accumulation, activating antioxidant enzymes and reducing hydrogen peroxide (H2O2) production under Cd stress. We conclude that PeCPK21 interacts with AtNF-YC3 to limit Cd accumulation and enhance the reactive oxygen species (ROS) scavenging system and thereby positively regulate plant adaptation to Cd environments. This study highlights the interaction between PeCPK21 and AtNF-YC3 under Cd stress conditions, which can be utilized to improve Cd tolerance in higher plants.

Combating Parkinson's disease with plant-derived polyphenols: Targeting oxidative stress and neuroinflammation

Parkinson's disease (PD) is a devastating neurodegenerative disorder predominantly affecting the elderly, characterized by the loss of dopaminergic neurons in the substantia nigra. Reactive oxygen species (ROS) generation plays a central role in the pathogenesis of PD and other neurodegenerative diseases. An imbalance between cellular antioxidant activity and ROS production leads to oxidative stress, contributing to disease progression. Dopamine metabolism, mitochondrial dysfunction, and neuroinflammation in dopaminergic neurons have been implicated in the pathogenesis of Parkinson's disease. Consequently, there is a pressing need for therapeutic interventions capable of scavenging ROS. Current pharmacological approaches, such as L-dihydroxyphenylalanine (levodopa or L-DOPA) and other drugs, provide symptomatic relief but are limited by severe side effects. Researchers worldwide have been exploring alternative compounds with less toxicity to address the multifaceted challenges associated with Parkinson's disease. In recent years, plant-derived polyphenolic compounds have gained significant attention as potential therapeutic agents. These compounds exhibit neuroprotective effects by targeting pathophysiological responses, including oxidative stress and neuroinflammation, in Parkinson's disease. The objective of this review is to summarize the current understanding of the neuroprotective effects of various polyphenols in Parkinson's disease, focusing on their antioxidant and anti-inflammatory properties, and to discuss their potential as therapeutic candidates. This review highlights the progress made in elucidating the molecular mechanisms of action of these polyphenols, identifying potential therapeutic targets, and optimizing their delivery and bioavailability. Well-designed clinical trials are necessary to establish the efficacy and safety of polyphenol-based interventions in the management of Parkinson's disease.