Search Results (223)

During exercise, increased oxygen consumption results in elevated production of reactive oxygen species (ROS). If the antioxidant system is unable to counteract this surge in ROS, oxidative stress occurs. Physical activity modulates both the generation and clearance of ROS through dynamic interactions between metabolic and antioxidant systems, and also influences the oxidative burst activity of phagocytes, a key component of the innate immune response. To investigate the acute physiological responses to high-intensity interval training (HIIT), we assessed the effects of a single HIIT session on oxidative stress markers and the oxidative burst activity of phagocytes in young professional athletes and non-athlete individuals. Blood samples were collected before and after a HIIT session from eleven male athletes (mean age: 22.1 ± 4.5 years) and ten male non-athlete university students (mean age: 21.6 ± 2.3 years). Participants performed a single treadmill HIIT session of ten 45-s intervals at 75–85% of heart rate reserve, separated by 45-s low-intensity recovery periods, with target intensities individualized using the Karvonen formula. Total antioxidant capacity, activities of catalase, superoxide dismutase and glutathione peroxidase enzymes, total serum nitrite/nitrate levels, lipid peroxidation products, and oxidative burst activity of phagocytes were evaluated before and after exercise. In athletes, a significant increase was observed in the activity of superoxide dismutase (from a median of 2.09 to 2.21 U/mL; p = 0.037) and catalase (from a median of 32.94 to 45.45 nmol/min/mL; p = 0.034) after exercise, whereas no significant changes were found in the control group. Total serum nitrite/nitrate levels significantly increased in both groups after exercise (athletes: from a median of 8.70 to 9.95 µM; p = 0.029; controls: from a median of 10.20 to 11.50 µM; p = 0.016). Oxidative burst capacity of peripheral blood phagocytes was significantly higher in athletes both before (median: 10,422 vs. 6766; p = 0.029) and after (median: 9365 vs. 7370; p = 0.047) the HIIT session compared to controls. Our findings demonstrate that training status markedly influences oxidative stress responses, with athletes exhibiting more effective long-term antioxidant adaptations. These results emphasize the necessity of tailoring exercise regimens to baseline fitness levels in order to optimize oxidative stress management across different populations. Full article

ROS derived from NADPH oxidase, particularly NOX2, are central to antimicrobial defense, coupling direct pathogen killing with redox signaling that shapes inflammation. This narrative review integrates recent advances on NOX2 structure, assembly, and spatiotemporal control in phagocytes, and outlines how ROS interact with NF-κB, MAPK, and Nrf2 networks to coordinate microbicidal activity and immune modulation. We summarize evidence that both ROS deficiency, as in chronic granulomatous disease, and uncontrolled excess, as in sepsis and severe COVID-19, drive clinically significant pathology, emphasizing the need for precise redox balance. Emerging therapeutic strategies include selective NOX2 inhibitors that limit pathological oxidative bursts, redox-modulating peptides that disrupt upstream activation cues, and Nrf2 activators that enhance endogenous antioxidant capacity, with attention to dosing challenges that preserve host defense while mitigating tissue injury. Key gaps remain in biomarker standardization, real-time in vivo ROS monitoring, and translation from animal models to patients, motivating personalized, combination approaches to redox medicine in infectious diseases. Full article

This study evaluates the performance of a hybrid passive optical network–radio over fiber (PON–RoF) architecture for long-term evolution (LTE)-based video transmission, focusing on the analysis of the block error rate (BLER) with and without an external RF amplifier. The results show that removing it improves receiver sensitivity by 4.04 dB in the optical link and 16 dB in the hybrid RoF link. The internal gain control of the USRP-2944R (Universal Software Radio Peripheral) is sufficient for signal processing without saturating the receiver. Furthermore, the received power levels are consistent with typical GPON sensitivity and overload ranges reported in standards, although the experimental setup corresponds to a continuous point-to-point laboratory link rather than a full GPON burst-mode configuration. Full article

Per- and polyfluoroalkyl substances (PFAS) persist in soils, yet their effects on invertebrate immunity remain poorly understood. We compared a legacy congener, perfluorooctanoic acid (PFOA), with three short-chain ether acids GenX (C6), MOBA (C5), and MOPrA (C4) using a 72 h OECD-207 filter-paper assay in the earthworm Eisenia fetida. Endpoints spanned cellular and humoral defenses: amoebocyte morphometry, oxidative burst (ROS production), phenol oxidase (PO) activity, and the transcription of the lectin CCF-1 and the pore-forming protein lysenin. MOBA and MOPrA caused enlargement of amoebocytes, whereas PFOA and GenX had no morphometric impact. Oxidative burst fell significantly for all congeners. PO inhibition followed the same potency order (MOPrA > GenX > MOBA ≫ PFOA), with near-complete loss at 229 µM MOPrA. Gene expression assays for CCF-1 and lysenin showed shifts in relative fold change for each PFAS congener. The combined biomarker panel—amoebocyte size, ROS, CAT, PO, CCF-1, and lysenin—offers a concise framework for assessing terrestrial PFAS risk and guiding remediation monitoring. Full article

As one of the key vectors for the transmission of Dengue fever, Aedes albopictus is highly ecologically adaptable. The development of environmentally compatible biological defence and control technologies has therefore become an urgent need for vector biological control worldwide. This study constructed and used double-stranded RNA (dsRNA) expression vectors targeting the cyp314a1 and cyp315a1 genes of Ae. albopictus to transform Chlamydomonas reinhardtii and Chlorella vulgaris, achieving RNA interference (RNAi)-mediated gene silencing. The efficacy of the RNAi recombinant algal strain biocide against Ae. albopictus was evaluated by administering it to Ae. albopictus larvae. The results showed that the oral administration of the cyp314a1 and cyp315a1 RNAi recombinant C. reinhardtii/C. vulgaris strains was lethal to Ae. albopictus larvae and severely affected their pupation and emergence. The recombinant algal strains triggered a burst of ROS (Reactive Oxygen Species) in the mosquitoes’ bodies, resulting in significant increases in the activities of the superoxide dismutase (SOD), peroxiredoxin (POD) and catalase (CAT), as well as significant upregulation of the mRNA levels of the CME pathway genes in larvae. In the simulated field experiment, the number of Ae. albopictus was reduced from 1000 to 0 in 16 weeks by the RNAi recombinant Chlorella, which effectively controlled the population of mosquitoes. Meanwhile, the levels of nitrogen (N), phosphorus (P), nitrate, nitrite, ammonia and COD (Chemical Oxygen Demand) in the test water decreased significantly. High-throughput sequencing analyses of 18S rDNA and 16S rDNA showed that, with the release of RNAi recombinant Chlorella into the test water, the biotic community restructuring dominated by resource competition caused by algal bloom, as well as the proliferation of anaerobic bacteria and the decline of aerobic bacteria triggered by anaerobic conditions, are the main trends in the changes in the test water. This study is an important addition to the use of RNAi recombinant microalgae as a biocide. Full article

Reactive oxygen species (ROS) are among the most effective tools of the innate immune response against pathogenic microbes. The respiratory burst (RB) of polymorphonuclear leukocytes (PMNs) generates an electron current that reduces molecular oxygen to superoxide. Superoxide reacts to form hydrogen peroxide as a precursor to the highly bactericidal hypochlorous acid. Here, we investigated whether alterations in extracellular potassium concentration impact H₂O₂ production. Such changes may occur, for example, during massive cell death due to necrosis or due to trauma injuries when potassium diffuses out of the cells. We recorded H₂O₂ release over a 2 h period of RB under varying potassium concentrations. Except for 100 mM potassium chloride, which increased the time delay before detectable H₂O₂ production, none of the potassium concentrations had a substantial effect on RB. We further examined whether this effect depended on the specific monovalent ion species. When sodium or methanesulfonate was used instead of potassium or chloride, respectively, no changes in H₂O₂ production were observed. Cell volume measurements under different potassium concentrations showed that only 100 mM potassium chloride significantly shrank the cells. We propose that hypertonic stress is crucial for delaying RB in human granulocytes, whereas the RB itself is independent of the tested ionic species. Additionally, the conducted hypertonic stress experiments revealed an unexpected time-dependence during the course of the RB, showing that the first 6 min were almost inert to hyperosmotic stress. Full article

Plant respiratory burst oxidase homolog (Rboh) genes are integral to the production of reactive oxygen species (ROS) and the regulation of stress responses. Here, bioinformatic techniques were employed to identify eight PgRboh genes (PgRbohA–H) in the genome of pomegranate (Punica granatum L.) and conduct a systematic analysis of this family. The findings showed that all PgRbohs proteins possess characteristic NADPH oxidase domains and are predicted to be localized on the cell membrane. Experimental verification confirmed the membrane localization of PgRbohD and PgRbohE proteins. Phylogenetic analysis categorized the PgRbohs proteins into six distinct groups, suggesting potential functional divergence among these groups. Promoter analysis revealed a significant presence of cis-acting elements responsive to low-temperature and methyl jasmonate (MeJA). The expression of PgRboh genes was found to be tissue-specific. Additionally, real-time PCR (RT-qPCR) was used to analyze expression patterns in response to low-temperature stress that involves multiple PgRboh genes in the cold response process. Overall, our results lay an important foundation for subsequent studies on the cold resistance function of pomegranate Rboh genes and provides new ideas for the breeding of new cold-resistant pomegranate varieties. Full article

Our previous research has demonstrated the role of optimal temperatures and reactive oxygen species (ROS) in maintaining symptomless nonhost resistance (NHR) of barley to powdery mildews. However, the exact functions of temperature and ROS in NHR of plants, including barley, to viral infections are not known. Although barley is a nonhost for Tobacco mosaic virus (TMV), this virus can replicate in barley leaves at temperatures of ca. 30 °C. Here we elucidated the influence of short-term heat stress pre-treatments (30 °C, 3 h; heat shock at 49 °C, 20 s) on the symptomless NHR of barley to TMV and the role of the ROS superoxide (O₂^.−) in maintaining NHR. Heat stress and antioxidant (superoxide dismutase and catalase, SOD + CAT) treatments resulted in 50–100% higher TMV levels, while combined heat shock and SOD + CAT application caused further increases in TMV and appearance of cell and tissue death resembling a hypersensitive response (HR). An early (from 2 h after inoculation) burst of O₂^.− was essentially absent in TMV-infected barley exposed to short-term heat stress pre-treatments. Expression of barley genes regulating ROS (O₂^.−) metabolism (HvRBOHF2, HvSOD1) and cell death (HvBI-1) displayed an inverse correlation with TMV levels even at later time points (1–4 days after inoculation), implying a role in symptomless NHR, while increased levels of the antioxidant glutathione marked heat stress-induced suppression of NHR. We demonstrated that short-term heat stress and antioxidant treatments result in compromised NHR of barley to TMV, pointing to the role of optimal temperatures and ROS (O₂^.−) in symptomless NHR to virus infections. Full article

The pathogenic plant fungus Bipolaris maydis is responsible for southern corn leaf blight (SCLB), a widespread agricultural disease that significantly reduces maize yield in various agroecological zones. The present research focuses on characterizing the role of Trichoderma harzianum cellobiohydrolase (CBH) Thph2 in induced maize resistance to SCLB by triggering the production of reactive oxygen species (ROS) in leaves. First of all, we demonstrated the potential activities of Thph2 in triggering ROS burst and PDC in a model plant, Nicotiana benthamiana. Cell death, ROS burst, and programmed cell death (PCD) were observed in N. benthamiana leaves following transient expression of Thph2, indicating its defensive role against Sclerotinia sclerotiorum infection. The removal of the signal peptide from Thph2 resulted in the complete loss of the cell death phenotype and the accumulation of reactive oxygen species (ROS), confirming that Thph2 functions as a microbial elicitor that primes host plant immunity through ROS-mediated signaling, thereby inducing systemic resistance (ISR). Furthermore, the Thph2 protein conferred resistance against B. maydis in maize, significantly increasing reactive oxygen species (ROS) accumulation (1.5-fold compared to the control) at 48 h post-inoculation (hpi),and leading to the reduction in the lesion area of SCLB by 15.9% at 2 days post-inoculation (dpi). Our results demonstrated that the Thph2 protein markedly enhanced the expression of lox5, aos, and hpl in maize leaves, thereby confirming its function in triggering plant defense mechanisms primarily via the jasmonic acid signaling pathway. This research reveals new molecular mechanisms by which T. harzianum enhances plant defense and showcases the biocontrol efficacy of Thph2 against southern corn leaf blight (SCLB). Full article

Oxybenzone (OBZ), an organic ultraviolet filter, is an emerging contaminant posing severe threats to ecosystem health. Using tobacco (Nicotiana tabacum) as a model plant, this study investigated the alleviation mechanisms of exogenous silicon (Na₂SiO₃, Si) and bamboo-based biochar (Bc) under OBZ stress. We systematically analyzed physiological and biochemical responses, including phenotypic parameters, reactive oxygen species metabolism, photosynthetic function, chlorophyll synthesis, and endogenous hormone levels. Results reveal that OBZ significantly inhibited tobacco growth and triggered a reactive oxygen species (ROS) burst. Additionally, OBZ disrupted antioxidant enzyme activities and hormonal balance. Exogenous Bc mitigated OBZ toxicity by adsorbing OBZ, directly scavenging ROS, and restoring the ascorbate-glutathione (AsA-GSH) cycle, thereby enhancing photosynthetic efficiency, while Si alleviated stress via cell wall silicification, preferential regulation of root development and hormonal signaling, and repair of chlorophyll biosynthesis precursor metabolism and PSII function. The mechanisms of the two stress mitigators were complementary, Bc primarily relied on physical adsorption and ROS scavenging, whereas Si emphasized metabolic regulation and structural reinforcement. These findings provide practical strategies for simultaneously mitigating organic UV filter pollution and enhancing plant resilience in contaminated soils. Full article

In this investigation, a hierarchical FeCo-layered double hydroxide (FeCo-LDH) electrochemical membrane material was prepared by a simple in situ hydrothermal method. The prepared material formed a 3D honeycomb-structured FeCo-LDH-modified carbon felt (FeCo-LDH/CF) catalytic layer with uniform open pores on a CF substrate with excellent catalytic activity and was served as the cathode in a flow-through electro-Fenton (FTEF) reactor. The electrocatalyst demonstrated excellent treatment performance (99%) in phenol simulated wastewater (30 mg L⁻¹) under the optimized operating conditions (applied voltage = 3.5 V, pH = 6, influent flow rate = 15 mL min⁻¹) of the FTEF system. The high removal rate could be attributed to (i) the excellent electrocatalytic oxidation performance and low interfacial charge transfer resistance of the FeCo-LDH/CF electrode as the cathode, (ii) the ability of the synthesized FeCo-LDH to effectively promote the conversion of H₂O₂ to •OH under certain conditions, and (iii) the flow-through system improving the mass transfer efficiency. In addition, the degradation process of pollutants within the FTEF system was additionally illustrated by the •OH dominant ROS pathway based on free radical burst experiments and electron paramagnetic resonance tests. This study may provide new insights to explore reaction mechanisms in FTEF systems. Full article

Background: Verticillium wilt (VW), caused by the fungal pathogen Verticillium dahliae, is a destructive disease that severely compromises cotton yield and fiber quality. Pyrimidine nucleotides, as essential metabolites and nucleic acid components, play critical roles in plant development and stress responses. However, genes involved in pyrimidine metabolism, especially their roles in disease resistance, remain largely uncharacterized in plants. Methods: Ghir_D05G039120, a gene encoding uridine kinase, shown to be associated with VW resistance in our previous study, was cloned and named as GhUKL4. The differential expression of GhUKL4 between the resistant and susceptible cultivars at multiple time points post-inoculation with V. dahliae was analyzed by quantitative real-time PCR (qRT-PCR), and the uracil phosphoribosyl transferase (UPRT) and uridine 5′-monophosphate kinase (UMPK) domains were verified by analyzing the amino acid sequences of GhUKL4. The role of GhUKL4 in the defense against VW infection was estimated by silencing GhUKL4 in the resistant and susceptible cultivars using virus-induced gene silencing (VIGS) analysis. Results: There were significant differences in the expression level of Ghir_D05G039120/ GhUKL4 among resistant and susceptible cotton lines. GhUKL4 contains UPRTase and UMPK domains, and there was one SNP between the resistant and susceptible cultivars in its 3′-UTR region. The silencing of GhUKL4 reduced cotton’s resistance to VW through mediating hormone signaling (JA) and oxidative stress (ROS) pathways. Conclusions: GhUKL4, encoding UMPK and UPRTase domain proteins, is a new regulatory factor associated with VW resistance in Gossypium hirsutum through fine-tuning JA-signalling and ROS bursting. Full article

We have previously shown that the mitochondrial respiratory chain (RC) can switch between the following two states: (i) an “ATP-producing” state characterized by the low production of reactive oxygen species (ROS), the vigorous translocation of hydrogen ions (H⁺), and the storage of energy from the H⁺ gradient in the form of ATP, and (ii) an “ROS-producing” state, where the translocation of H⁺ is slow but the production of ROS is high. Here, we suggest that the RC transition from an ATP-producing to an ROS-producing state initiates a mitochondrial permeability transition (MPT) by generating a burst of ROS. Numerous MPT activators induce the transition of the RC to an ROS-producing state, and the ROS generated in this state activate the MPT. The MPT, in turn, induces changes in conditions that are necessary for the RC to return to an ATP-producing state, decreasing the ROS production rate and restoring the normal permeability of the inner membrane. In this way, the transient MPT prevents cell damage from oxidative stress that would occur if the RC remained in an ROS-producing state. It is shown that an overload of glutamate, which enters through excitatory amino acid transporters (EAATs), induces the RC to switch to an ROS-producing state. Subsequent MPT activation causes a transition back to an ATP-producing state. The model was used to predict the spatial–temporal dynamics of glutamate concentrations and H₂O₂ production rates in a three-dimensional digital phantom of nervous tissue. Full article

The growing prevalence of bacterial infections and the alarming rise of antimicrobial resistance (AMR) have driven the need for innovative antimicrobial coatings for medical implants and biomaterials. However, implant surface properties, such as roughness, chemistry, and reactivity, critically influence biological interactions and must be engineered to ensure biocompatibility, corrosion resistance, and sustained antibacterial activity. This review evaluates three principal categories of antimicrobial agents utilized in surface functionalization: metal/metaloxide nanoparticles, antibiotics, and phytochemical compounds. Metal/metaloxide-based coatings, especially those incorporating silver (Ag), zinc oxide (ZnO), and copper oxide (CuO), offer broad-spectrum antimicrobial efficacy through mechanisms such as reactive oxygen species (ROS) generation and bacterial membrane disruption, with a reduced risk of resistance development. Antibiotic-based coatings enable localized drug delivery but often face limitations related to burst release, cytotoxicity, and diminishing effectiveness against multidrug-resistant (MDR) strains. In contrast, phytochemical-derived coatings—using bioactive plant compounds such as curcumin, eugenol, and quercetin—present a promising, biocompatible, and sustainable alternative. These agents not only exhibit antimicrobial properties but also provide anti-inflammatory, antioxidant, and osteogenic benefits, making them multifunctional tools for implant surface modification. The integration of these antimicrobial strategies aims to reduce bacterial adhesion, inhibit biofilm formation, and enhance tissue regeneration. By leveraging the synergistic effects of metal/metaloxide nanoparticles, antibiotics, and phytochemicals, next-generation implant coatings hold the potential to significantly improve infection control and clinical outcomes in implant-based therapies. Full article

Citral, an organic compound found in lemongrass (Cymbopogon citratus) oil and Litsea cubeba essential oil, has been reported to exhibit notable antifungal activity against Magnaporthe oryzae (M. oryzae), the pathogen of rice blast, which causes significant economic losses in rice production. However, the role of citral in inducing oxidative stress related to antifungal ability and its underlying regulatory networks in M. oryzae remain unclear. In this study, we investigated the oxidative effects of citral on M. oryzae and conducted transcriptomic and widely targeted metabolomic (WTM) analyses on the mycelia. The results showed that citral induced superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) activities but reduced glutathione S-transferase (GST) activity with 25% maximal effective concentration (EC₂₅) and 75% maximal effective concentration (EC₇₅). Importantly, citral at EC₇₅ reduced the activities of mitochondrial respiratory chain complex I, complex III and ATP content, while increasing the activity of mitochondrial respiratory chain complex II. In addition, citral triggered a burst of reactive oxygen species (ROS) and a loss of mitochondrial membrane potential (MMP) through the observation of fluorescence. Furthermore, RNA-seq analysis and metabolomics analysis identified a total of 466 differentially expression genes (DEGs) and 32 differential metabolites (DAMs) after the mycelia were treated with citral. The following multi-omics analysis revealed that the metabolic pathways centered on AsA, GSH and melatonin were obviously suppressed by citral, indicating a disrupted redox equilibrium in the cell. These findings provide further evidences supporting the antifungal activity of citral and offer new insights into the response of M. oryzae under oxidative stress induced by citral. Full article