ROS-scavenging Capacity Research Articles

Drought-mediated oxidative stress and its scavenging differ between citrus hybrids with medium and late fruit maturation

Drought stress is a major environmental factor limiting citrus productivity. Still, differences in drought sensitivity between citrus hybrids of different maturation periods have so far not been reported. Here, we selected a medium-maturing (Fertile orange: FO (Citrus reticulata cv. Fertile orange) and a late-maturing citrus hybrid (Newhall Navel orange: NO (Citrus sinensis Osbeck cv. Newhall) and determined the physiological and biochemical traits of leaves, roots, wood and bark. Our results showed that drought significantly decreased net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of citrus leaves. Oxidative stress upon drought was indicated by enhanced foliar malondialdehyde (MDA) and hydrogen peroxide contents, as well as a stimulation of the anti-oxidative system. This stimulation included the contents of dehydroascorbic acid (DHA), glutathione (GSH) and oxidized glutathione (GSSG) in leaves, roots, wood and bark, as well as activities of antioxidative enzymes of glutathione reductase (GR), dehydroascorbate reductase (DHAR), superoxide dismutase (SOD) and peroxidase (POD). The late maturing NO hybrid not only showed better general physiological performance as indicated by increased Pn in leaves, but also higher biochemical ROS scavenging and osmotic capacity as indicated by increased ascorbic acids (ASA), DHA, and proline contents, as well as activities of enzymes of SOD, POD, ASA/DHA and GSH/GSSG ratios in the investigated tissues compared to the FO hybrid under drought and control conditions. Analysis of molecular mechanisms of signaling, regulatory and functional genes expression are suggested for future studies to elucidate the complex interplay of molecular, biochemical and physiological responses of citrus hybrids to drought.

Comparison and Assessment of Anti-Inflammatory and Antioxidant Capacity Between EGCG and Phosphatidylcholine-Encapsulated EGCG.

To compare and evaluate the differences between EGCG and phosphatidylcholine-encapsulated EGCG in terms of their anti-inflammatory and antioxidant capacities. In this study, transdermal absorption experiments were conducted to compare the absorption capacity of EGCG and phosphatidylcholine-encapsulated EGCG. Subsequently, the disparity in anti-inflammatory and antioxidant efficacy between EGCG and phosphatidylcholine-encapsulated EGCG were evaluated through cytotoxicity experiments, as well as the determination of cellular inflammatory factors and the measurement of ROS content under different treatment conditions. The concentration of EGCG, encapsulated in phosphatidylcholine, in porcine skin is 40.76 ± 1.29 μg/cm2, which is significantly higher than the concentration of EGCG alone (31.62 ± 2.01 μg/cm2). Also, the ability of phosphatidylcholine-encapsulated EGCG to suppress inflammatory factors such as tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), and prostaglandin E2 (PGE2) was notably superior to that of EGCG alone. Both phosphatidylcholine-encapsulated EGCG and EGCG showed excellent ROS scavenging ability in terms of antioxidant capacity. The percutaneous absorption and anti-inflammatory impact of EGCG encapsulated within phosphatidylcholine were substantially enhanced when compared to EGCG by itself. Additionally, both formulations exhibited enhanced ROS scavenging capacities, albeit the variance between them was not pronounced. These insights furnish a vital theoretical underpinning for the utilization of phosphatidylcholine-encapsulated EGCG in cosmetic applications, specifically for fostering products with anti-inflammatory and antioxidant benefits.

The long non-coding RNA ROSALIND protects the mitochondrial translational machinery from oxidative damage.

Upregulation of mitochondrial respiration coupled with high ROS-scavenging capacity is a characteristic shared by drug-tolerant cells in several cancers. As translational fidelity is essential for cell fitness, protection of the mitochondrial and cytosolic ribosomes from oxidative damage is pivotal. While mechanisms for recognising and repairing such damage exist in the cytoplasm, the corresponding process in the mitochondria remains unclear.By performing Ascorbate PEroXidase (APEX)-proximity ligation assay directed to the mitochondrial matrix followed by isolation and sequencing of RNA associated to mitochondrial proteins, we identified the nuclear-encoded lncRNA ROSALIND as an interacting partner of ribosomes. ROSALIND is upregulated in recurrent tumours and its expression can discriminate between responders and non-responders to immune checkpoint blockade in a melanoma cohort of patients. Featuring an unusually high G content, ROSALIND serves as a substrate for oxidation. Consequently, inhibiting ROSALIND leads to an increase in ROS and protein oxidation, resulting in severe mitochondrial respiration defects. This, in turn, impairs melanoma cell viability and increases immunogenicity both in vitro and ex vivo in preclinical humanised cancer models. These findings underscore the role of ROSALIND as a novel ROS buffering system, safeguarding mitochondrial translation from oxidative stress, and shed light on potential therapeutic strategies for overcoming cancer therapy resistance.

Screening and preparation of highly active antioxidant peptides of apricot and their inhibitory effect on ultraviolet radiation

In today's social environment, the objective reality of people's increasing life pressure, environmental deterioration, and enhanced ultraviolet rays caused by the destruction of the ozone layer has led to the aggravation of people's oxidative stress. Therefore, exogenous antioxidant peptides have become a hot topic in research. In the context of insufficient protein supply and resource recycling, almond meal was used as raw material in this study. As a by-product of oil processing, it has a protein content of 68 % and antioxidant-related amino acids accounted for 84.62 %, which can be used as a high-quality natural source of antioxidant peptides. Taking antioxidant activity as the only indicator, papain was screened as a hydrolase, and 7 antioxidant peptides such as YLSF, LPSYVN and SPHWNVN were separated and purified. The affinity energy of docking with Keap1-Nrf2-ARE protein molecules was −7.5—-8.9 kal/mol, and hydrophobic stacking, hydrogen bonding and intermolecular forces were maintained. Seven antioxidant peptides were synthesized in solid phase, and the IC50 values of in vitro ABTS+ scavenging rates were 3.59 μg/mL-6.73 μg/mL, and the antioxidant capacity was stronger than that of glutathione and ascorbic acid. In the in vitro cellular ROS scavenging capacity, all seven peptides had the effect of scavenging intracellular ROS, among which YLSF and ESWNPRDPQF had stronger scavenging capacity than glutathione. Finally, the mouse skin staining method determined that apricot antioxidant peptides had a significant inhibitory effect on UV damage to mouse skin, and targeted proteomics was used to clarify that apricot antioxidant peptides inhibited UV damage by mainly affecting three pathways, including the base excision repair pathway. This study not only improved the economic value of processing by-products, but also obtained 7 highly active almond antioxidant peptides, tapping the potential ability of apricot antioxidant peptides to be incorporated into functional food or cosmetic formulations.

Piriformospora indica alleviates soda saline-alkaline stress in Glycine max by modulating plant metabolism.

Soil salinization is one of the major factors limiting agricultural production. Utilizing beneficial microorganisms like Piriformospora indica (P. indica) to enhance plant tolerance to abiotic stresses is a highly effective method, but the influence of P. indica on the growth of soybean in natural saline-alkaline soil remains unclear. Therefore, we investigated the effects of non-inoculation, P. indica inoculation, and fertilization on the growth, antioxidant defense, osmotic adjustment, and photosynthetic gas exchange parameters of soybean under two different levels of saline-alkaline stress in non-sterilized natural saline-alkaline soil. The study found that: 1) P. indica inoculation significantly promoted soybean growth, increasing plant height, root length, and biomass. Under mildly saline-alkaline stress, the increases were 11.5%, 16.0%, and 14.8%, respectively, compared to non-inoculated treatment. Under higher stress, P. indica inoculation achieved the same level of biomass increase as fertilization, while fertilization only significantly improved stem diameter. 2) Under saline-alkaline stress, P. indica inoculation significantly increased antioxidant enzyme activities and reduced malondialdehyde (MDA) content. Under mildly stress, MDA content was reduced by 47.1% and 43.3% compared to non-inoculated and fertilized treatments, respectively. Under moderate stress, the MDA content in the inoculated group was reduced by 29.9% and 36.6% compared to non-inoculated and fertilized treatments, respectively. Fertilization only had a positive effect on peroxidase (POD) activity. 3) P. indica inoculation induced plants to produce more osmotic adjustment substances. Under mildly stress, proline, soluble sugars, and soluble proteins were increased by 345.7%, 104.4%, and 6.9%, respectively, compared to non-inoculated treatment. Under higher stress, the increases were 75.4%, 179.7%, and 12.6%, respectively. Fertilization had no significant positive effect on proline content. 4) With increasing stress, soybean photosynthetic capacity in the P. indica-inoculated treatment was significantly higher than in the non-inoculated treatment, with net photosynthetic rate increased by 14.8% and 37.0% under different stress levels. These results indicate that P. indica can enhance soybean's adaptive ability to saline-alkaline stress by regulating ROS scavenging capacity, osmotic adjustment substance content, and photosynthetic capacity, thereby promoting plant growth. This suggests that P. indica has great potential in improving soybean productivity in natural saline-alkaline soils.

Physiological and molecular responses of 'Hamlin' sweet orange trees expressing the VvmybA1 gene under cold stress conditions.

Overexpression of VvmybA1 transcription factor in 'Hamlin' citrus enhances cold tolerance by increasing anthocyanin accumulation. This results in improved ROS scavenging, altered gene expression, and stomatal regulation, highlighting anthocyanins' essential role in citrus cold acclimation. Cold stress is a significant threat to citrus cultivation, impacting tree health and productivity. Anthocyanins are known for their role as pigments and have emerged as key mediators of plant defense mechanisms against environmental stressors. This study investigated the potential of anthocyanin overexpression regulated by grape (Vitis vinifera) VvmybA1 transcription factor to enhance cold stress tolerance in citrus trees. Transgenic 'Hamlin' citrus trees overexpressing VvmybA1 were exposed to a 30-day cold stress period at 4°C along with the control wild-type trees. Our findings reveal that anthocyanin accumulation significantly influences chlorophyll content and their fluorescence parameters, affecting leaf responses to cold stress. Additionally, we recorded enhanced ROS scavenging capacity and distinct expression patterns of key transcription factors and antioxidant-related genes inthe transgenic leaves. Furthermore, VvmybA1 overexpression affected stomatal aperture regulation by moderating ABA biosynthesis, resulting in differential responses in a stomatal opening between transgenic and wild-type trees under cold stress. Transgenic trees exhibited reduced hydrogen peroxide levels, enhanced flavonoids, radical scavenging activity, and altered phytohormonal profiles. These findings highlighted the role of VvmybA1-mediated anthocyanin accumulation in enhancing cold tolerance. The current study alsounderlines the potential of anthocyanin overexpression as a critical regulator of the cold acclimation process by scavenging ROS in plant tissues.

Enhanced In Vitro Efficacy of Verbascoside in Suppressing Hepatic Stellate Cell Activation via ROS Scavenging with Reverse Microemulsion.

Numerous approaches targeting hepatic stellate cells (HSCs) have emerged as pivotal therapeutic strategies to mitigate liver fibrosis and are currently undergoing clinical trials. The investigation of herbal drugs or isolated natural active compounds is particularly valuable, due to their multifaceted functions and low risk of side effects. Recent studies have hinted at the potential efficacy of verbascoside (VB) in ameliorating renal and lung fibrosis, yet its impact on hepatic fibrosis remains to be elucidated. This study aims to evaluate the potential effects of VB on liver fibrosis by assessing its ability to inhibit HSC activation. VB demonstrated significant efficacy in suppressing the expression of fibrogenic genes in activated LX-2 cells. Additionally, VB inhibited the migration and proliferation of these activated HSCs by scavenging reactive oxygen species (ROS) and downregulating the AMPK pathway. Furthermore, a biosafe reverse microemulsion loaded with VB (VB-ME) was developed to improve VB's instability and low bioavailability. The optimal formulation of VB-ME was meticulously characterized, revealing substantial enhancements in cellular uptake, ROS-scavenging capacity, and the suppression of HSC activation.

An NIR-propelled janus nanomotor with enhanced ROS-scavenging, immunomodulating and biofilm-eradicating capacity for periodontitis treatment

Periodontitis is an inflammatory disease caused by bacterial biofilms, which leads to the destruction of periodontal tissue. Current treatments, such as mechanical cleaning and antibiotics, struggle to effectively address the persistent biofilms, inflammation, and tissue damage. A new approach involves developing a Janus nanomotor (J-CeM@Au) by coating cerium dioxide-doped mesoporous silica (CeM) with gold nanoparticles (AuNPs). This nanomotor exhibits thermophoretic motion when exposed to near-infrared (NIR) laser light due to the temperature gradient produced by the photothermal effects of asymmetrically distributed AuNPs. The NIR laser provides the energy for propulsion and activates the nanomotor's antibacterial properties, allowing it to penetrate biofilms and kill bacteria. Additionally, the nanomotor's ability to scavenge reactive oxygen species (ROS) can modulate the immune response and create a regenerative environment, promoting the healing of periodontal tissue. Overall, this multifunctional nanomotor offers a promising new approach for treating periodontitis by simultaneously addressing biofilm management and immune modulation with autonomous movement.

Enhancing diabetic wound healing: A two-pronged approach with ROS scavenging and ROS-independent antibacterial properties

The intricate microenvironment often hinders diabetic wounds from following a normal healing process, marked by prolonged low-grade inflammation, thereby slowing or stalling wound healing. Nanomedicine stands as a pivotal branch in the evolution of therapeutic strategies, yet grapples with inherent conflicting traits – the ROS-dependent antibacterial properties of most materials and the anti-inflammatory ROS-scavenging capabilities. This study introduces a multifunctional MOF-199/GO nanocomposite designed to promote diabetic wound healing by its robust ROS scavenging capacity, ROS-independent antibacterial and anti-biofilm properties, and the ability to modulate wound microenvironments. In a skin wound model on type I diabetes rats, the addition of MOF-199/GO efficiently orchestrates the healing process into the defined phases of inflammation, proliferation, and remodeling, achieving a remarkable 96 % wound closure by day 10. When employed as a drug, MOF-199/GO exhibits minimal biological toxicity in vivo. Moreover, when combined with various dressing materials, the drug’s performance remains unchanged, indicating its practical application value.

Cell-free fat extract regulates oxidative stress and alleviates Th2-mediated inflammation in atopic dermatitis.

Atopic dermatitis (AD) is a common inflammatory skin disease that significantly affects patients' quality of life. This study aimed to evaluate the therapeutic potential of cell-free fat extract (FE) in AD. In this study, the therapeutic effect of DNCB-induced AD mouse models was investigated. Dermatitis scores and transepidermal water loss (TEWL) were recorded to evaluate the severity of dermatitis. Histological analysis and cytokines measurement were conducted to assess the therapeutic effect. Additionally, the ability of FE to protect cells from ROS-induced damage and its ROS scavenging capacity both in vitro and in vivo were investigated. Furthermore, we performed Th1/2 cell differentiation with and without FE to elucidate the underlying therapeutic mechanism. FE reduced apoptosis and cell death of HaCat cells exposed to oxidative stress. Moreover, FE exhibited concentration-dependent antioxidant activity and scavenged ROS both in vitro and vivo. Treatment with FE alleviated AD symptoms in mice, as evidenced by improved TEWL, restored epidermis thickness, reduced mast cell infiltration, decreased DNA oxidative damage and lower inflammatory cytokines like IFN-γ, IL-4, and IL-13. FE also inhibited the differentiation of Th2 cells in vitro. Our findings indicate that FE regulates oxidative stress and mitigates Th2-mediated inflammation in atopic dermatitis by inhibiting Th2 cell differentiation, suggesting that FE has the potential as a future treatment option for AD.

Surface-Engineered Titanium with Nanoceria to Enhance Soft Tissue Integration Via Reactive Oxygen Species Modulation and Nanotopographical Sensing.

The design of implantable biomaterials involves precise tuning of surface features because the early cellular fate on such engineered surfaces is highly influenced by many physicochemical factors [roughness, hydrophilicity, reactive oxygen species (ROS) responsiveness, etc.]. Herein, to enhance soft tissue integration for successful implantation, Ti substrates decorated with uniform layers of nanoceria (Ce), called Ti@Ce, were optimally developed by a simple and cost-effective in situ immersion coating technique. The characterization of Ti@Ce shows a uniform Ce distribution with enhanced roughness (∼3-fold increase) and hydrophilicity (∼4-fold increase) and adopted ROS-scavenging capacity by nanoceria coating. When human gingival fibroblasts were seeded on Ti@Ce under oxidative stress conditions, Ti@Ce supported cellular adhesion, spreading, and survivability by its cellular ROS-scavenging capacity. Mechanistically, the unique nanocoating resulted in higher expression of amphiphysin (a nanotopology sensor), paxillin (a focal adhesion protein), and cell adhesive proteins (collagen-1 and fibronectin). Ti@Ce also led to global chromatin condensation by decreasing histone 3 acetylation as an early differentiation feature. Transcriptome analysis by RNA sequencing confirmed the chromatin remodeling, antiapoptosis, antioxidant, cell adhesion, and TGF-β signaling-related gene signatures in Ti@Ce. As key fibroblast transcription (co)factors, Ti@Ce promotes serum response factor and MRTF-α nucleus localization. Considering all of this, it is proposed that the surface engineering approach using Ce could improve the biological properties of Ti implants, supporting their functioning at soft tissue interfaces and utilization as a bioactive implant for clinical conditions such as peri-implantitis.

Structure elucidation and antioxidant activity of a polysaccharide from Penthorum chinense Pursh

Penthorum chinense Pursh is a traditional Miao medicine, mainly used in the treatment of liver diseases. In this study, an acidic heteropolysaccharide PCPP was isolated from P. chinense with an average molecular weight of 14.96 kDa. PCPP contained arabinogalactan and homogalacturonan segments, which is formed by 4-Galp-(1 → 5)-Araf-1 and 3,6-Galp-(1 → 6)-Galp-1,3 glycosidic linkage. A variety of side chains, including t-Glcp-(1 → 4)-Glcp-(1 → 4)-GlcpA-1, t-Xylp-(1→, and 2-Manp-(1 → 4)-GalpA-1,3 linked to the O-3 and O-6 of 3,6-Galp. The antioxidant activity measurement in three models demonstrated that PCPP exhibited ROS scavenging capacity, antioxidant ability in the cellular model, enhancement of oxidative stress resistance, and healthspan-promoting effect in the worm model. These results provided the theoretical fundament of PCPP as a potential natural antioxidant.

Melatonin-Derived Carbon Dots with Free Radical Scavenging Property for Effective Periodontitis Treatment via the Nrf2/HO-1 Pathway.

Periodontitis is a chronic inflammatory disease closely associated with reactive oxygen species (ROS) involvement. Eliminating ROS to control the periodontal microenvironment and alleviate the inflammatory response could potentially serve as an efficacious therapy for periodontitis. Melatonin (MT), renowned for its potent antioxidant and anti-inflammatory characteristics, is frequently employed as an ROS scavenger in inflammatory diseases. However, the therapeutic efficacy of MT remains unsatisfactory due to the low water solubility and poor bioavailability. Carbon dots have emerged as a promising and innovative nanomaterial with facile synthesis, environmental friendliness, and low cost. In this study, melatonin-derived carbon dots (MT-CDs) were successfully synthesized via the hydrothermal method. The MT-CDs have good water solubility and biocompatibility and feature excellent ROS-scavenging capacity without additional modification. The in vitro experiments proved that MT-CDs efficiently regulated intracellular ROS, which maintained mitochondrial homeostasis and suppressed the production of inflammatory mediators. Furthermore, findings from the mouse model of periodontitis indicated that MT-CDs significantly inhibited the deterioration of alveolar bone and reduced osteoclast activation and inflammation, thereby contributing to the regeneration of damaged tissue. In terms of the mechanism, MT-CDs may scavenge ROS, thereby preventing cellular damage and the production of inflammatory factors by regulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. The findings will offer a vital understanding of the advancement of secure and effective ROS-scavenging platforms for more biomedical applications.

Effect of reduced glutathione on quality, lipid peroxidation and antioxidant potential of frozen‐thawed ring‐necked pheasant semen

AbstractReduced glutathione (GSH) is a natural redox force immediately consumed by cells to combat toxins. Today's world is shifting towards clean farming practices whence ring‐necked pheasants dependent on croplands are facing threats and sperm‐assisted reproductive techniques become indispensable in preserving this valuable species for game and meat purposes. This study aims at evaluating the cryosurvivability (motility, viability, plasma membrane and acrosomal integrity, DNA fragmentation) and antioxidant capacity (Free radical scavenging activity, LPO detection, Ferric reducing antioxidant power, mitochondrial status) of ring‐necked pheasant semen with GSH supplementation in the extender. Semen collected from ten males was pooled, divided and diluted with Beltsville poultry semen extender (1:5) containing 0.0, 0.2, 0.4, 0.6 and 0.8 mM GSH. Samples were cryopreserved, and sperm quality was evaluated post‐dilution, cooling, equilibration, and freeze–thaw. Free radical scavenging activity, total antioxidant potential, mitochondrial action and lipid peroxidation were assessed at post‐thawing. Sperm motility, plasma membrane and acrosomal integrity, viability and DNA integrity were recorded highest (p < .05) at 0.4 mM GSH compared to other concentrations and control at all the stages of cryopreservation. Similarly, sperm mitochondrial action, antioxidant potential and free radical scavenging capacity were recorded higher (p < .05) with 0.4 mM GSH at post‐thaw compared to other concentrations of GSH and control. Lipid peroxidation was recorded as highest (p < .05) in the control compared to GSH‐supplemented groups at post‐thaw. Hence, it is concluded that GSH at 0.4 mM preserves the quality and ROS scavenging capacity of cryopreserved ring‐necked pheasant sperm as an antioxidant.

Red emissive carbon dots Self-Cascading antioxidant nanozymes combine with anti-miRNA-155 for accurate monitoring and ameliorating rheumatoid arthritis

Accurate monitoring and effective antioxidant treatment strategies are highly desirable in rheumatoid arthritis (RA) amelioration. Herein, cerium (Ce) and selenium (Se) co-doped carbon dots (CS-CDs) integrated superoxide dismutase (SOD)-like and glutathione peroxidase (GPx)-like self-cascading catalytic activity are engineered. In this self-cascading nanozymes system, Ce active center catalyzes ·O2− to H2O2 by mimicking SOD, and the adjacent Se component sequentially decomposes the H2O2 by mimicking GPx, achieving enhanced catalytic and superior reactive oxygen species (ROS)-scavenging activities. CS-CDs further load cyanine-5 (Cy5)-labeled anti-miRNA-155 to realize macrophage subphenotype identification via miRNA-155 ratiometric imaging for RA accurate monitoring, and regulate the polarization of pro-inflammatory macrophages for synergistic RA amelioration. Comprehensive in vitro and in vivo experiments validate the advanced RA monitoring and therapy performance of the self-cascading nanozymes. This work not only offers a rationally designed self-cascading nanozyme with simple structures and intriguing ROS-scavenging capacity, but also opens up a strategy for accurate RA monitoring and synergistic amelioration.

Chemopreventive effects of α-tocopherol and its long-chain metabolites α-13'-hydroxy- and α-13'-carboxychromanol in LT97 colon adenoma cells.

Anticancer effects of vitamin E (tocopherols) have been studied extensively. While in vitro and animal studies showed promising results regarding anticancer effects of tocopherols, human intervention studies failed to reproduce these results. In vivo, α-tocopherol (α-TOH) is metabolized to the long-chain metabolites (LCM) 13'-hydroxychromanol (α-13'-OH) and 13'-carboxychromanol (α-13'-COOH), which likely reach the large intestine. The LCM showed antiproliferative effects in different colon cancer cell lines, but the exact mechanism of action remains unclear. To further clarify the chemopreventive action of the LCM, premalignant LT97 colon adenoma cells were treated with α-TOH, α-13'-OH and α-13'-COOH to study their impact on growth, apoptosis, antigenotoxicity, and ROS-scavenging capacity as well as expression of selected genes involved in detoxification and the cell cycle. Growth inhibitory potential was observed for α-13'-OH (IC50: 37.4 μM) and α-13'-COOH (IC50: 5.8 μM) but not for α-TOH in the tested concentrations. Levels of caspase-3 activity and expression of genes regulating the cell cycle and detoxification remained unchanged. However, α-TOH, α-13'-OH and α-13'-COOH exhibited antigenotoxic and partly ROS-scavenging capacity. The results indicate that the LCM exert chemopreventive effects via ROS-scavenging capacity, the protection against DNA damage and the induction of cell death via caspase-independent mechanisms in premalignant colon cells.

Photosynthetic adaptation strategies in peppers under continuous lighting: insights into photosystem protection.

Energy efficient lighting strategies have received increased interest from controlled environment producers. Long photoperiods (up to 24 h - continuous lighting (CL)) of lower light intensities could be used to achieve the desired daily light integral (DLI) with lower installed light capacity/capital costs and low electricity costs in regions with low night electricity prices. However, plants grown under CL tend to have higher carbohydrate and reactive oxygen species (ROS) levels which may lead to leaf chlorosis and down-regulation of photosynthesis. We hypothesize that the use of dynamic CL using a spectral change and/or light intensity change between day and night can negate CL-injury. In this experiment we set out to assess the impact of CL on pepper plants by subjecting them to white light during the day and up to 150 µmol m-2 s-1 of monochromatic blue light at night while controlling the DLI at the same level. Plants grown under all CL treatments had similar cumulative fruit number and weight compared to the 16h control indicating no reduction in production. Plants grown under CL had higher carbohydrate levels and ROS-scavenging capacity than plants grown under the 16h control. Conversely, the amount of photosynthetic pigment decreased with increasing nighttime blue light intensity. The maximum quantum yield of photosystem II (Fv/Fm), a metric often used to measure stress, was unaffected by light treatments. However, when light-adapted, the operating efficiency of photosystem II (ΦPSII) decreased and non-photochemical quenching (NPQ) increased with increasing nighttime blue light intensity. This suggests that both acclimated and instantaneous photochemistry during CL can be altered and is dependent on the nighttime light intensity. Furthermore, light-adapted chlorophyll fluorescence measurements may be more adept at detecting altered photochemical states than the conventional stress metric using dark-adapted measurements.

A Ti3C2 MXene-integrated near-infrared-responsive multifunctional porous scaffold for infected bone defect repair.

Infected bone defect repair has long been a major challenge in orthopedic surgery. Apart from bacterial contamination, excessive generation of reactive oxygen species (ROS), and lack of osteogenesis ability also threaten the defect repair process. However, few strategies have been proposed to address these issues simultaneously. Herein, we designed and fabricated a near-infrared (NIR)-responsive, hierarchically porous scaffold to address these limitations in a synergetic manner. In this design, polymethyl methacrylate (PMMA) and polyethyleneimine (PEI) were used to fabricate the porous PMMA/PEI scaffolds via the anti-solvent vapor-induced phase separation (VIPS) process. Then, Ti3C2 MXenes were anchored on the scaffolds through the dopamine-assisted co-deposition process to obtain the PMMA/PEI/polydopamine (PDA)/MXene scaffolds. Under NIR laser irradiation, the scaffolds were able to kill bacteria through the direct contact-killing and synergetic photothermal effect of Ti3C2 MXenes and PDA. Moreover, MXenes and PDA also endowed the scaffolds with excellent ROS-scavenging capacity and satisfying osteogenesis ability. Our experimental results also confirmed that the PMMA/PEI/PDA/MXene scaffolds significantly promoted new bone formation in an infected mandibular defect model. We believe that our study provides new insights into the treatment of infected bone defects.

Reactive Oxygen Species Scavenging Nanozymes: Emerging Therapeutics for Acute Liver Injury Alleviation.

Acute liver injury (AIL), a fatal clinical disease featured with a swift deterioration of hepatocyte functions in the short term, has emerged as a serious public health issues that warrants attention. However, theeffectivenessof existing small molecular antioxidants and anti-inflammatory medications in alleviating AIL remainsuncertain. The uniqueinherent structural characteristics of liver confer it a natural propensity for nanoparticle capture, which present an opportunity to exploit in the formulation of nanoscale therapeutic agents, enabling their selective accumulation in the liver and thereby facilitating targeted therapeutic interventions. Significantly increased reactive oxygen species (ROS) accumulation and inflammation response have been evidenced to play crucial roles in occurrence and development of AIL. Nanozymes with ROS-scavenging capacities have demonstrated considerable promise in ROS elimination and inflammation regulation, thereby offering an appealing therapeutic instrument for the management of acute liver injury. In this review, the mechanisms of different type of ALI were summarized. In addition, we provide a comprehensive summary and review of the available ROS-scavenging nanozymes, including transition metal-based nanozymes, noble metal nanozymes, carbon-based nanozymes, and some other nanozymes. Furthermore, the challenges still need to be solved in the field of ROS-scavenging nanozymes for ALI alleviation are also discussed.

DgHDA6 enhances the cold tolerance in chrysanthemum by improving ROS scavenging capacity

Histone deacetylases have been demonstrated to play an important role in responding to low-temperature stress, but the related response mechanism in chrysanthemum remains unclear. In this study, we isolated a cold-induced gene, DgHDA6, from chrysanthemum (Chrysanthemum morifolium Ramat). DgHDA6 contains 474 amino acids and shares a typical deacetylation domain with RPD3/HDA1 family members. The overexpression of DgHDA6 enhanced cold resistance in chrysanthemums. After low-temperature stress, the overexpression lines showed a higher survival rate. The contents of proline, soluble proteins and sugars, and the activities of antioxidant enzymes were significantly increased while the contents of H2O2, O2− and MDA were lower. Moreover, cold-stress-responding genes such as DgCuZnSOD, DgCAT, DgP5CS, and DgFAD were upregulated after cold stress. These results suggest that the overexpression of DgHDA6 can improve cold tolerance in chrysanthemum by enhancing ROS scavenging capacity.