Search Results (2,754)

Mitochondrial electron transport chain (ETC) dysfunction is a major driver of bioenergetic failure, redox imbalance, and drug toxicity, yet strategies to restore oxidative phosphorylation under ETC blockade remain limited. Redox-active small molecules could, in principle, shuttle electrons from NADH to distal ETC components and oxygen, thereby modulating both respiration and reactive oxygen species (ROS) formation. Here, we show that the enzyme-independent redox cycler phenazine methosulfate (PMS) rewires mitochondrial redox circuits and restores respiration in human glioblastoma cells and cell-free systems under ETC inhibition. At subtoxic concentrations, PMS acutely increased oxygen consumption and mitochondrial superoxide generation via NADH–PMS–O₂ redox cycling, while restoring mitochondrial membrane potential and ATP synthesis under ETC blockade, and shifting metabolism away from glycolytic lactate production. This profile is consistent with a protective redox-bypass role, distinct from the pro-apoptotic effects reported following high-dose, prolonged PMS exposure. The PMS-driven restoration of electron flow, mitochondrial membrane potential, and respiratory ATP synthesis under inhibition of Complex I (rotenone), III (antimycin A and myxothiazol), and/or IV (cyanide) is consistent with direct cytochrome c reduction, as demonstrated herein, and engagement of multiple ETC redox centers, including coenzyme Q₁₀. In metformin-treated cells, PMS reversed suppression of respiration and lactate accumulation, outperforming existing redox-bypass strategies. These findings identify PMS-driven redox cycling as a previously unrecognized chemical redox-bypass mechanism that both regenerates mitochondrial bioenergetics and reshapes ROS production, suggesting a potential approach to counteract drug- and toxin-induced mitochondrial dysfunction and to exploit redox vulnerabilities in cancer. Full article

Mitochondrial reactive oxygen species (mtROS) are central regulators of cellular function, yet their biological roles are often reduced to an oxidative-stress/antioxidant dichotomy. This review reframes mtROS through the concept of mitohormesis, in which outcomes are neither inherently harmful nor beneficial but are determined by a defined set of contextual variables. We present a mechanistic framework in which mtROS effects depend on chemical species identity, sub-mitochondrial site of production, temporal dynamics, redox-buffering capacity, and metabolic state; together, these variables determine whether mtROS promote adaptive eustress or pathological distress. We then show that, across polyphenols, isothiocyanates, terpenoids, alkaloids, and quinones, the biologically relevant effects of natural redox-modulating compounds are mediated less by direct radical scavenging than by pro-hormetic mechanisms, including mild electron transport chain perturbation, nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (NRF2/KEAP1) activation, modulation of mitochondrial membrane potential, mitochondrial quality control, and NAD⁺/NADPH regulation. Applying this framework to disease reveals strong tissue and state dependence: neurodegeneration favors buffering expansion and mitophagy; metabolic disease may benefit from exercise-mimetic and NRF2-activating strategies; cardiovascular disease illustrates mitohormesis through ischemic preconditioning and CoQ10 supplementation; and cancer requires distinction between prevention and therapy because redox buffering can either protect normal tissue or support tumor survival. Finally, we argue that the failure of non-specific antioxidant supplementation is mechanistically predictable and propose context-aware, biomarker-guided, temporally optimized, and compartment-targeted redox interventions as a more rational translational path. Full article

This meta-analysis combined the results of 61 independent studies published in 2005–2025 to examine polyamine-mediated responses to aluminum, cadmium, lead, chromium, copper, manganese, and selenium stress in plants. The logarithm ratio of responses (lnRR) under the random-effects model was used to calculate the effect sizes. Polyamine application significantly (p < 0.001) enhanced plant growth, with strong increases in root elongation (lnRR = 0.490, 95% CI: 0.362–0.618), fresh weight (lnRR = 0.413, 95% CI: 0.347–0.480), and dry weight (lnRR = 0.475, 95% CI: 0.409–0.541). Oxidative stress was markedly reduced, as reflected by decreases in reactive oxygen species accumulation (lnRR = −0.585, 95% CI −0.682 to −0.487, p < 0.001), hydrogen peroxide content (lnRR = 0.005, 95% CI −0.244 to 0.254, p = 0.968), and lipid peroxidation (lnRR = −0.487, 95% CI −0.578 to −0.397, p < 0.001). The antioxidant defenses were strengthened, and the levels of superoxide dismutase (lnRR = 0.468, p < 0.001) and catalase activity (lnRR = 0.373, p < 0.001) increased significantly. Metal accumulation was consistently reduced in polyamine-treated plants (lnRR = −0.392, 95% CI −0.460 to −0.324, p < 0.001). Supplementary genetic-level data indicated that metal stress triggers polyamines to regulate metal transporters, polyamine biosynthesis genes, antioxidant-related genes, and hormone-signaling pathways. Collectively, these data points make polyamines a key controller of plant metal stress tolerance and offer a quantitative and mechanistic system to apply them to metal-impacted agroecosystems. Full article

Climate change has intensified the occurrence of combined abiotic stresses such as drought, salinity, heat, and waterlogging, thereby threatening cereal productivity and global food security. Root systems play a central role in plant adaptation to these interacting stresses by regulating water uptake, ion balance, nutrient acquisition, and stress signaling. However, many previous studies have primarily focused on individual stress factors rather than integrated stress environments. This review synthesizes current knowledge regarding root-mediated adaptive mechanisms in cereal crops under combined abiotic stresses, with emphasis on barley (Hordeum vulgare), wheat (Triticum aestivum), and oats (Avena sativa). The review highlights how root system architecture, including root depth, branching density, and aerenchyma formation, contributes to stress resilience under interacting environmental conditions. Physiological and molecular mechanisms involving ion transporters, aquaporins, transcription factors, and auxin-regulated root plasticity are also discussed. In barley, deeper and steeper root systems improve water acquisition under combined drought and heat stress, while wheat genotypes carrying the HKT1;5 allele exhibit enhanced sodium exclusion under drought–salinity interactions. Oats respond to waterlogging and salinity through adventitious root formation and enhanced oxygen transport. Overall, this review emphasizes the importance of root-targeted approaches for improving cereal adaptation under increasingly complex multi-stress environments. Full article

Against the backdrop of the global energy transition, novel oxygen separation technologies that combine high selectivity, high permeability, and stability have become the key to overcoming industrial bottlenecks. Mixed ion–electron conductor (MIEC) ceramic oxygen transport membranes (OTMs), with their 100% oxygen selectivity, high oxygen permeability, and low energy consumption, are regarded as the most promising next-generation oxygen separation technology. Compared with traditional oxygen production approaches including cryogenic distillation and pressure swing adsorption (PSA), these solutions make up for their inherent defects. They have extensive application prospects in oxygen-enriched combustion, CCUS, high-efficiency hydrogen preparation and chemical synthesis processes. This paper systematically reviews the progress in the oxygen transport mechanisms, material systems, structural design, and fabrication processes of MIEC oxygen permeable membranes. Finally, we conducted an in-depth analysis of the key challenges OTMs face when applied to oxygen-enriched combustion including stability in high-temperature, complex flue gas environments and the optimization of oxygen permeability and offered insights into future research and industrialization directions. Full article

Oxygen transfer enhancement in aquaculture was investigated using a low-cost fine-bubble spray system operated under controlled hydrodynamic conditions. Experiments were conducted under oxygen-depleted conditions (initial DO = 2.4 mg L⁻¹), and oxygen transfer kinetics were evaluated using the dynamic method. The dissolved oxygen concentration increased to 6.2 mg L⁻¹ within 1 h, corresponding to a net oxygen transfer of 9.55 ± 0.46 g. The volumetric mass transfer coefficient (kLa) was determined to be 1.44 h⁻¹ (R² = 0.97), while the specific oxygen transfer efficiency (SOTE) reached 76.4 ± 7.8 gO₂ kWh⁻¹. Dimensionless analysis (Re ≈ 2 × 10⁴, Sc ≈ 500, Sh ≈ 682) indicates a turbulent, convection-dominated transport regime. Biological observations showed a 43% increase in fish growth under spray-assisted conditions, indicating improved oxygen availability. The observed oxygen transfer enhancement was primarily associated with hydrodynamic interfacial area generation rather than diffusion-limited transport. The low-power configuration and simplified system design suggest potential applicability for decentralized aquaculture operations. The proposed approach also provides an engineering framework for evaluating low-cost aeration technologies under aquaculture operating conditions. Full article

Current knowledge on the toxic effects of microplastics (MPs) on human health relies on the extrapolation of data collected from in vivo studies. These studies, however, present limitations, as the particles used often differ from their environmental counterparts. Nevertheless, they provide valuable insights into the mechanisms underlying MPs’ toxicity. In this study, we targeted the mitochondria to investigate the effects of two types of polyethylene microplastics (PE MPs, 27–32 µm), fluorescent and non-fluorescent, on kidneys from FVB/n mice. Animals were exposed for 28 days to two environmentally relevant concentrations of PE MPs (0.002% (w/w) and 0.006% (w/w)). Results reveal that both MPs induce mitochondrial dysfunction, as indicated by oxygen flux depletion in different coupling-controlled states. Complex II dysfunction, particularly at the highest concentration of fluorescent particles, and alterations in other components of the electron transport chain were identified as one of the causes of mitochondrial dysfunction. MPs’ exposure also induced subtle remodelling of the mitochondrial membrane lipid profile, marked by shifts in specific saturated and unsaturated fatty acids, suggesting an adaptive response to preserve membrane integrity. These alterations were accompanied by oxidative stress, evidenced by decreased SOD and CAT activities, particularly under high concentrations of fluorescent PE MPs. Overall, fluorescent MPs triggered stronger mitochondrial and metabolic disruptions in the kidney. All together, these findings reinforce mitochondria as pivotal targets of MPs’ toxicity and highlight the need for improved experimental models that better reflect environmentally relevant exposure scenarios. Full article

Hydrogen molecules can serve as a promising clean energy supplier; conventional hydrogen production usually relies on fossil fuels and leads to intense greenhouse gas emissions. Significant emphasis has been placed on exploring sustainable and renewable hydrogen resources. Cyanobacteria can convert solar energy into hydrogen through oxygen-sensitive hydrogenases or nitrogenases. However, practical application remains severely constrained by oxygen-evolving photosynthesis, inefficient electron allocation, and the low metabolic priority of hydrogen production in cyanobacterial cells. In recent years, substantial progress has been achieved in understanding hydrogen metabolism and improving hydrogen production through physiological regulation, hydrogenase engineering, photosynthetic electron transport chain (PETC) reconstruction, metabolic engineering, and biohybrid systems. This review summarizes recent advances in cyanobacterial hydrogen production, with particular emphasis on hydrogen-producing pathways, key limiting factors, and current engineering strategies. Importantly, this review highlights that many currently reported strategies still provide only transient improvements because hydrogen production is constrained by system-level conflicts among photosynthesis, redox balance, carbon fixation, and cellular stability. In addition, emerging approaches including metagenomic resource mining, synthetic biology, AI-assisted engineering, biohybrid photoelectrochemical systems, and techno-economic optimization are discussed as potential directions for improving the efficiency, scalability, and practical feasibility of cyanobacterial hydrogen production technologies in the future. Full article

The mitochondrial membrane protein UPS1, a conserved intermembrane space protein in Saccharomyces cerevisiae, possesses phosphatidic acid transfer activity and plays a positive regulatory role in processes such as cardiolipin metabolism and transport. The role of UPS1 protein in pathogenic fungi such as Candida albicans has not been explored, especially in relation to its influence on virulence factors like hyphal growth and biofilm formation, which are crucial for the pathogenicity of C. albicans. The research investigated the function of the UPS1 protein in C. albicans by using gene knockout techniques, analyzing mitochondrial function, and conducting tests for hyphal and biofilm development. The results revealed that deletion of the UPS1 gene leads to altered mitochondrial morphology, increased reactive oxygen species levels, and reduced intracellular ATP content, thereby causing severe growth defects in C. albicans. In addition, transcriptomic analysis indicated that loss of UPS1 significantly represses the expression of genes associated with hyphal growth and biofilm formation. Functional assays further confirmed that UPS1 deficiency markedly impairs cell adhesion capability, hyphal development, and biofilm formation of C. albicans. Notably, deletion of the UPS1 protein markedly reduces the susceptibility of C. albicans to membrane-targeted antifungal drugs. Finally, infection models using Galleria mellonella larvae and a murine vulvovaginal candidiasis model verified that UPS1 gene knockout attenuates the pathogenicity of C. albicans. In summary, our findings demonstrate that UPS1 protein modulates the pathogenicity of C. albicans by regulating mitochondrial function, hyphal growth, and biofilm formation. Full article

Transition-metal oxide/layered double hydroxide (LDH) electrodes often suffer from insufficient utilization of active sites, sluggish electron/ion transport, and limited cycling stability at high rates. Here, La-doped ZnCo₂O₄/MnCo-LDH nanoflowers serve as the positive electrode and Ti-supported Sb-doped SnO₂ (Ti/Sb-SnO₂) serves as the negative electrode for constructing an asymmetric supercapacitor. A stepwise hydrothermal route, La-doping regulation, and ethylenediamine-assisted morphology control transform stacked nanosheets into open porous nanoflowers with a specific surface area of 382.5 m² g⁻¹, thereby exposing more electroactive sites and shortening OH⁻ diffusion pathways. La³⁺-induced lattice distortion and defect-related oxygen species further tune the electronic structure and improve interfacial charge-transfer kinetics. The optimized La-ZnCo₂O₄/MnCo-LDH electrode delivers 2130 F g⁻¹ at 1 A g⁻¹ and retains 1993 F g⁻¹ after 10,000 cycles at 3 A g⁻¹. The Ti/Sb-SnO₂ negative electrode provides 673 F g⁻¹ at 1 A g⁻¹ and 302 F g⁻¹ at 15 A g⁻¹. The assembled device operates stably from 0 to 1.8 V in 2 M KOH and achieves 69 Wh kg⁻¹ and 13,500 W kg⁻¹. Full article

Reactive polymeric membranes are emerging as promising platforms for advanced water and wastewater treatment because they combine separation with in situ contaminant transformation. Unlike conventional membranes, which mainly retain pollutants, reactive polymeric membranes can enrich, activate, and degrade micropollutants during permeation through built-in radical, redox-active, conductive, or porous catalytic domains. This review discusses the development of intrinsic reactive polymer membranes for oxidative filtration, with emphasis on the links between polymer structure, transport behavior, reactive oxygen species generation, and degradation pathways. Key membrane classes are discussed, including stable-radical polymers, redox-active polymer networks, conductive polymer membranes, and porous conjugated polymer catalytic layers. The review also highlights the importance of reactive transport kinetics, including convection–diffusion–reaction coupling, residence time, Damköhler and Péclet numbers, and adsorption-enhanced degradation. Challenges such as fouling, polymer aging, leaching, byproduct formation, and toxicity-aware benchmarking are discussed within a broader roadmap for technology translation. The review identifies the grand challenges and milestone-based priorities for developing and deploying reactive polymer membranes, including performance targets, standardized reporting, realistic water matrices, scale-up, technology readiness levels, techno-economic analysis, life cycle assessment, artificial intelligence, and digital twins. Together, these elements guide the translation of reactive polymer membrane systems from laboratory research toward full-scale water treatment applications. Full article

Perovskite-type oxides are among the most promising cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) due to their mixed ionic–electronic conductivity and compositional flexibility. Many high-performance cathodes rely on Sr substitution at the A-site, often associated with surface segregation and long-term degradation. In this work, we explore an alternative strategy based on defect engineering and phase interactions in Sr-free composites. Perovskite-fluorite composites based on LaFe_0.8Co_0.2O₃ were synthesized through a one-pot route designed to promote the formation of a perovskite phase and a limited amount of fluorite-type ceria. This approach allows the introduction of small fractions of Ce into the perovskite lattice, favoring the cooperative coexistence with La-doped CeO₂. Structural, microstructural and spectroscopic characterization indicates that Ce influences the crystallization pathway and composite defect chemistry. Variations in lattice parameters and Raman features suggest modifications of perovskite structure consistent with defect formation and lattice distortion. Reduction properties and electrical conductivity measurements indicate that Ce incorporation in the perovskite and oxide interaction affect charge transport and oxygen mobility. The electrochemical results demonstrate that the optimal trade-off between activation energy (Ea) and polarization resistance (Rp) is achieved for the sample, with a nominal cerium content, Ce/(La + Ce) of 0.16. Moreover, the electrochemical properties are found to correlate with the nominal cerium content, which regulates defect chemistry and the resulting composite composition. Overall, results suggest that the one-pot synthesis promotes beneficial interactions between the perovskite and ceria phases, allowing the development of Sr-free ferrite-based materials with enhanced functional properties, minimizing the amount of ceria in the composite. Full article

Hypoxia-induced radioresistance remains a major obstacle in non-small cell lung cancer (NSCLC) radiotherapy. This study investigates whether artificially activating mitochondrial reverse electron transfer (RET) can enhance radiosensitivity in NSCLC by triggering oxidative stress. An in vitro hypoxia/reoxygenation (H/R) model was established in A549 cells to assess reactive oxygen species (ROS) levels, mitochondrial function, and metabolic alterations using fluorescence probes, flow cytometry, confocal microscopy, and targeted metabolomics. Mitochondrial complex inhibitors and dimethyl succinate (DM-S) were employed to validate the RET mechanism, and radiosensitivity was evaluated through clonogenic survival, apoptosis assays, and γ-H2AX staining. In vivo, A549 tumor-bearing mice received high oxygen (95% O₂) combined with DM-S and localized irradiation (4 Gy); tumor growth, histopathology, and immunohistochemistry were examined. H/R triggered substantial mitochondrial ROS production via complex I-mediated RET, dependent on a high mitochondrial membrane potential and electron transport chain imbalance, with succinate accumulation serving as a key metabolic switch. Exogenous DM-S exacerbated H/R-induced oxidative damage, DNA fragmentation (8-OHdG elevation, mtDNA integrity loss), and mitochondrial network disruption. H/R combined with DM-S significantly enhanced in vitro radiosensitivity, reducing clonogenic survival and increasing apoptosis to 53.4% ± 1.9% versus 10.3% ± 1.2% with irradiation alone. In vivo, the combination therapy markedly suppressed tumor growth, induced apoptosis and oxidative lipid damage (4-HNE), alleviated hypoxia (reduced HIF-1α), and showed no overt toxicity. These findings demonstrate that activating mitochondrial RET effectively enhances radiosensitivity in NSCLC. Succinate metabolism is a critical therapeutic target, and combining high oxygen with a succinate analog represents a promising radiosensitization strategy for hypoxic tumors. Full article

A critical challenge in coalbed methane (CBM) extraction is the severe formation damage induced by conventional foam fracturing fluids, primarily through polymer retention and hydrogen bond disruption within the microporous matrix. This study presents a molecularly engineered, low-damage foam fracturing fluid that leverages synergistic nanoparticle–surfactant interactions to construct a robust interfacial pseudo-gel network, thereby decoupling effective fracture stimulation from adverse geochemical damage. The primary novelties of this work are threefold: (i) establishing a direct, quantitative cause-and-effect relationship between molecular interfacial architecture and reservoir protection, (ii) proposing a comprehensive “interfacial control” design paradigm that engineers viscoelasticity at the gas–liquid interface rather than through bulk polymer gelation, and (iii) demonstrating the complete decoupling of foam stability from formation damage in a polymer-free system. A systematic optimization methodology was employed: initial foaming agents were screened via the Waring Blender method, evaluating foam volume, half-life, and a derived comprehensive index; subsequently, synergistic binary surfactant mixtures and foam stabilizers were assessed to formulate the final systems. An optimized formulation, designated Foam System I (0.5 wt.% fluorosurfactant FK + 0.5 wt.% nano-silica RX + 2.0 wt.% KCl), demonstrated exceptional foam quality (Γ = 77.1 ± 1.5%) and kinetic stability (T₁/₂ > 350 s). Rheological characterization confirmed shear-thinning behavior conforming to the Herschel–Bulkley model (n = 0.38–0.42, R² > 0.98) and a structural recovery of 92.5 ± 2.1%—comparable to crosslinked polymer gels but achieved without any bulk viscosifier. Core flood analyses revealed that Foam System I induced a permeability damage of only 12.75 ± 1.8%, representing a 55–75% reduction compared to polyethylene glycol (PEG)-stabilized reference fluids (28.36–51.91%). X-ray photoelectron spectroscopy (XPS) correlated this enhanced reservoir compatibility with an 18.0 ± 2.0% suppression of oxygen-containing functional group adsorption, attributed to the steric hindrance conferred by the fluorinated hydrophobic moieties. This work establishes an “interfacial control” paradigm wherein gel-like stabilization for proppant transport is achieved via interfacial viscoelasticity rather than bulk polymer gelation, thereby directly addressing the critical imperative to harmonize fracture conductivity with reservoir protection in unconventional energy development. The findings are validated for shallow CBM reservoir conditions (25–35 °C), with extension to higher-temperature formations identified as a priority for future investigation. Full article

No data to date are available on the underlying mechanisms by which coumarin (COU) alleviates plant aluminum (Al) toxicity. Citrus grandis (L.) Osbeck seedlings were submitted to 0 (Al0) or 1.2 (Al1.2 or Al³⁺ toxicity) mM AlCl₃·6H₂O and 0 (COU0) or 50 (COU50) μM COU for 18 weeks. The results demonstrated that COU50 attenuated Al1.2-induced decreases of seedling growth, chlorophyll (Chl) level, and CO₂ assimilation (A_CO2) and impairment of the photosynthetic electron transport chain (PETC). Further analysis suggested that reduced tissue Al concentration and enhanced capability to maintain nutrient and redox homeostasis played a role in COU-mediated amelioration of seedling growth inhibition, leaf Chl and A_CO2 decline, and PETC impairment. Notably, seedlings treated with COU0 showed some adaptive responses to Al1.2. For example, Al1.2 decreased the biosynthesis and accumulation of proteins and amino acids to meet the increased need for energy; increased the diphenylpicrylhydrazyl (DPPH) scavenging activity and phenolic compound accumulation to meet the elevated demand for reactive oxygen species (ROS) and Al detoxification; and increased the accumulation of soluble sugars (glucose, fructose, and sucrose) to meet the augmented demand for ROS scavenging and energy. To conclude, the research revealed some mechanisms for COU-mediated amelioration of plant Al³⁺ toxicity. Full article