Superoxide dismutases: ancient enzymes and new insights

Effect of sublethal doses of chlorantraniliprole on the activity of detoxification and protective enzymes in Galleria Mellonella (Lepidoptera: Pyralidae)

Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) is a pest that feeds on the spleen of honey bee nests worldwide. In this study, the toxicity of chlorantraniliprole (CAP) to G. mellonella was determined by ingestion toxicity and contact toxicity methods. We compared the effects of sublethal doses of CAP on the activity of major detoxification and protective enzymes as well as gene expression of related enzymes under the 2 treatment methods. The median lethal concentrations of CAP administered using ingestion toxicity and contact toxicity methods were 217.666 and 50.453 mg L-1, respectively. Compared with the control group, both methods increased the activities of carboxylesterase (CarE) and cytochrome P450 (CYP450), decreased the activities of glutathione S-transferase (GST) and peroxidase (POD), and had no effect on catalase activity. Superoxide dismutase activity decreased under ingestion toxicity but remained unchanged under contact toxicity. Significant changes were observed in the gene expression levels of detoxification and protective enzymes under both treatment methods; the expression levels of GmCarE4a, GmCarE2a, GmCarE1f, and GmPOD1a were significantly upregulated, whereas those of GmGST2a and GmGST2b were significantly downregulated. CAP exhibited both ingestion toxicity and contact toxicity against G. mellonella, with better contact toxicity effects. Galleria mellonella responded to CAP stress by adjusting enzyme activities (increasing CarE and CYP450 activities and decreasing GST and POD activities) and related gene expression levels (upregulating the relative expression levels of GmCarE4a, GmCarE2a, GmCarE1f, and GmPOD1a and downregulating those of GmGST2a and GmGST2b). The findings from the 2 distinct poisoning methods offer a scientific foundation for optimizing the application of CAP in the effective control of G. mellonella, while also providing valuable insights into the development of CAP resistance.

Oxidative Damage Under Microgravity Conditions: Response Mechanisms, Monitoring Methods and Countermeasures on Somatic and Germ Cells

With the growing human interest in space exploration, understanding the oxidative damage effects of microgravity on somatic and germ cells and their underlying mechanisms has become a pivotal scientific challenge for ensuring reproductive health during long-term space missions. In this review, we comprehensively summarize the molecular mechanisms of microgravity-induced oxidative stress, advanced detection methods, and potential protective strategies for germ cells. The evidence demonstrates that microgravity substantially compromises germ cell viability and embryonic developmental potential by disrupting mitochondrial function, increasing reactive oxygen species (ROS) production, and impairing antioxidant defenses. These alterations result in DNA damage, lipid peroxidation, and protein oxidation, thereby affecting cellular integrity and functionality. Furthermore, we discuss how cells respond to microgravity-induced oxidative stress through adaptive mechanisms, such as autophagy, apoptosis, and antioxidant systems, although these responses can have both beneficial and detrimental effects on cellular homeostasis. Additionally, this paper highlights the utility of fluorescent probes for detecting ROS levels under microgravity conditions, which are convenient and practical, but may require further optimization to improve sensitivity and specificity. To counteract these challenges, interventions such as antioxidants and artificial gravity systems show promise but need rigorous validation in prolonged microgravity environments. Finally, future research should integrate multi-omics approaches to unravel the oxidative damage network, advance space-adapted reproductive technologies, and provide essential theoretical insights and technical support for maintaining human reproductive health beyond Earth.

The influencing mechanisms of different characteristics of polystyrene microplastics on Saccharomyces cerevisiae: functional group, particle size and dosage

ABSTRACTBased on the well-documented hazards of microplastics and the importance and typicality of Saccharomyces cerevisiae (S. cerevisiae) in the environment, in this study, the influencing mechanisms of functional group, particle size and dosage of polystyrene microplastics (PS MPs) on S. cerevisiae were studied systematically. The results showed that compared with the bigger particle size and lower concentration of carboxylated PS MPs, the smaller particle size and higher concentration of aminated PS MPs had the most serious inhibition of the growth of S. cerevisiae, and their cell morphology was more abnormal, the more PS MPs attached to the yeast cells. The results of orthogonal experiment showed that the inhibitory effects of PS MPs on S. cerevisiae followed the order: functional groups > concentrations > particle sizes. Through the analysis of the antioxidant properties of S. cerevisiae, it was found that the activities of superoxide dismutase and catalase were first stimulated and then inhibited, and the concentrations of superoxide dismutase enzymes in the environment with bigger particle size and lower concentration of PS MPs was higher than that in the environment with smaller particle size and higher concentrations of PS MPs. catalase enzyme showed an opposite trend in particle sizes and a similar trend in concentrations. The concentrations of malondialdehyde increased with the increase of PS MPs concentrations and the decrease of particle sizes, indicating that PS MPs could induce S. cerevisiae to produce a large amount of reactive oxygen species, resulting in severe oxidative damage to S. cerevisiae.

Iron deficiency and toxicity trigger divergent metabolic responses and adaptive plasticity in Ulmus pumila: Insights from integrated transcriptomic and metabolomic analyses

Iron homeostasis is critical for plant growth; however, the mechanisms underlying responses to iron deficiency and toxicity remain poorly understood. We investigated the adaptive strategies of Ulmus pumila, focusing on leaf physiological, transcriptomic, and metabolomic responses to iron stresses. Both iron deficiency and toxicity impaired chlorophyll biosynthesis, PS II efficiency, and chloroplast ultrastructure, resulting in reduced photosynthetic capacity and etiolation/wilting phenotypes. Iron deficiency reduced antioxidant enzyme activity and ROS levels, while iron toxicity activated the antioxidant enzyme system in response to the ROS burst. Integrated transcriptomic and metabolomic analyses provided insights into the underlying mechanism of these divergent responses: iron deficiency promoted primary metabolic adjustments, particularly the upregulation of genes (e.g., MDH, ACO, and IDH) and metabolites (e.g., malic acid, citric acid, and fumaric acid) associated with the TCA cycle to meet energy demands. Conversely, iron toxicity triggered a metabolic shift from primary to secondary metabolism, upregulating the genes (e.g., CHS, CHI, and F3H) and metabolites (e.g., laricitrin, trifolin, and rutin) involved in flavonoids biosynthesis to mitigate oxidative stress. Overall, U. pumila employs distinct adaptive mechanisms to balance survival and growth under iron stress: prioritizing energy metabolism and iron uptake to meet energy demands and improve iron uptake efficiency under deficiency, and enhancing the secondary metabolism to mitigate oxidative damage under toxicity. These findings enhance understanding of plant nutrient homeostasis and stress adaptation, providing insights into mitigating the impacts of soil degradation on agriculture and forestry.

Novel Thermostable Manganese Superoxide Dismutase from Alicyclobacillus sp. with High Specific Activity and Antioxidant Properties

Superoxide dismutase (SOD) is a vital antioxidant enzyme that exerts antioxidative and anti-inflammatory effects on the host. In this study, a novel thermostable SOD of Alicyclobacillus sp. (AliSOD) from a hot spring was overexpressed in Escherichia coli, and enzymatic properties were identified. Mn2+ plays a decisive role in enzyme activity, indicating that AliSOD is MnSOD. Specifically, AliSOD was determined to be dimeric with a subunit molecular mass of 23.0 kDa, and the specific activity was confirmed to be as high as 24990.8 U·mg-1. AliSOD demonstrated exceptional thermal stability, broad pH stability, and resistance to urea, exhibiting minimal loss of activity at 70 °C and remarkable tolerance in an alkaline environment. Moreover, AliSOD significantly alleviated oxidative stress in diquat-injured cells (P < 0.01). It also increased intracellular SOD expression and activated the Nrf2 protein downstream of the Keap1-Nrf2 signaling pathway (P < 0.05). Overall, AliSOD exhibits excellent thermostability and specific activity, indicating potential applications in the pharmaceutical, food, and animal feed industries.

miR-34-5p, a potential RNA biopesticide for controlling Spodoptera frugiperda by targeting of SfEcR and SfE74

Spodoptera frugiperda is an agricultural pest with strong adaptability and migration ability. For decades, chemical control has been an important technical measure for controlling S. frugiperda. In the field of pest control, research on RNA biopesticides mainly focuses on dsRNA, and the application of miRNA biopesticides is still in its infancy. The miR-34 family is a multifunctional family that plays key roles in organ development, organism or organ aging, stress response, spermatogenesis, and signal transduction. In this study, we analyzed the physiological function of miR-34-5p by upregulating and downregulating its level, combined with a series of methods such as target site prediction, dual luciferase reporter gene detection, related gene expression, and intestinal reactive oxygen species (ROS) level detection. miR-34-5p plays a crucial role in the metamorphosis and development of S. frugiperda larvae. Among them, the molting related genes SfEcR and SfE74 were identified as the target genes for miR-34-5p, which suggests that miR-34-5p has the potential to serve as an RNA biopesticide. This work provides novel directions and ideas for the prevention and green control of S. frugiperda.

MnSOD non-acetylation mimic knock-in mice exhibit dilated cardiomyopathy

Manganese superoxide dismutase (MnSOD/SOD2) is an essential mitochondrial enzyme that detoxifies superoxide radicals generated during oxidative respiration. MnSOD/SOD2 lysine 68 acetylation (K68-Ac) is an important post-translational modification (PTM) that regulates enzymatic activity, responding to nutrient status or oxidative stress, and elevated levels have been associated with human illness. To determine the in vivo role of MnSOD-K68 in the heart, we used a whole-body non-acetylation mimic mutant (MnSODK68R) knock-in mouse. These mice exhibited several cardiovascular phenotypes, including lower blood pressure, decreased ejection fraction, and importantly, dilated cardiomyopathy, as evidenced by echocardiography at four months of age. In addition, both mouse embryo fibroblasts (MEFs) and cardiovascular tissue from MnSODK68R/K68R mice exhibited an increase in cellular senescence. Finally, MnSODK68R/K68R mouse hearts also showed an increase in lipid peroxidation. We conclude that constitutively active MnSOD detoxification activity, lacking the normal switch between non-acetylated and acetylated forms, dysregulates mitochondrial physiology during development, leading to dilated cardiomyopathy.

Computational scoring and experimental evaluation of enzymes generated by neural networks

In recent years, generative protein sequence models have been developed to sample novel sequences. However, predicting whether generated proteins will fold and function remains challenging. We evaluate a set of 20 diverse computational metrics to assess the quality of enzyme sequences produced by three contrasting generative models: ancestral sequence reconstruction, a generative adversarial network and a protein language model. Focusing on two enzyme families, we expressed and purified over 500 natural and generated sequences with 70-90% identity to the most similar natural sequences to benchmark computational metrics for predicting in vitro enzyme activity. Over three rounds of experiments, we developed a computational filter that improved the rate of experimental success by 50-150%. The proposed metrics and models will drive protein engineering research by serving as a benchmark for generative protein sequence models and helping to select active variants for experimental testing.

Gene transcription in the oyster Crassostrea gigas exposed to environmental concentrations of the UV filter Benzophenone-3

Personal care products (PCPs), such as sunscreens, are usually found in various aquatic ecosystems at low concentrations (ng l-1 to µg l-1). However, there is limited information regarding their effects on marine bivalves. Therefore, the aim of this study was to evaluate the sublethal effects of environmental concentrations (1 and 100 µg l-1) of benzophenone-3 (BP-3) in Crassostrea gigas oysters after 1 and 7 days of exposure. We analyzed the accumulation of BP-3 in the soft tissue of oysters and the transcription of genes associated with antioxidant enzyme (SOD and CAT), phase I biotransformation (CYP356A1, CYP2AU2 and CYP7A1), phase II biotransformation (GSTO.4A and GSTP.1.1) and nuclear receptors (NR) that regulate gene transcription: CgNR0B, CgNR1P10, CgNR1P11, CgNR2E2 and CgNR5A. The highest accumulation (34.9 ± 5.7 µg g-1) was observed in oysters exposed for 7 days to 100 µg l-1. Increased transcription of SOD and CYP356A1 genes was observed in oysters exposed at both concentrations after 1 day of exposure. Additionally, GSTP.1.1 transcription increased after 1 day of exposure to 100 µg l-1 but decreased after 7 days of exposure to 1 µg l-1. An increase in the transcription of CgNR0B and CgNR1P10 genes was observed in oysters exposed to 100 µg l-1 after 1 day of exposure, while only CgNR5A showed increased transcription after 1 and 7 days of exposure to 100 µg l-1. Finally, the IBRv2i was significantly higher in the 100 µg l-1 group compared to the control after 1 day of exposure. In conclusion, C. gigas exposed to concentrations that BP-3 could reach in nearshore areas exhibited variations in gene transcription, which could result in imbalances of physiological processes.

Based on network pharmacology and experimental validation, berberine can inhibit the progression of gastric cancer by modulating oxidative stress

Background

Gastric cancer (GC) is marked by high incidence, malignancy, and poor prognosis. Understanding its development mechanisms and discovering effective drugs are urgent needs. Elevated oxidative stress levels in GC patients have been linked to disease progression. Berberine, an isoquinoline alkaloid from Coptis chinensis, exhibits strong anti-GC properties without notable side effects. However, its impact and mechanisms regarding oxidative stress in GC remain unclear. This study aims to explore berberine's anti-GC mechanisms through network pharmacology and validate findings via in vitro experiments.

Methods

Berberine's target genes were sourced from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) and Comparative Toxicogenomics Database (CTD). GC-related targets were gathered from GeneCards, Online Mendelian Inheritance in Man (OMIM), PharmGkb, the Therapeutic Target Database (TTD), and DrugBank. The intersection of these targets facilitated the construction of a "drug-disease-target" network using Cytoscape 3.9.1. A protein-protein interaction (PPI) network was developed via the STRING database, and core targets were identified through visualization and topological analysis. Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using R. Subsequently, in vitro experiments validated the pharmacology predictions, evaluating berberine's effects on AGS and MKN45 GC cell viability and migration through Cell Counting Kit-8 (CCK-8) and cell scratch assays. The impact of berberine on reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) levels was assessed using specific detection kits. Additionally, the influence of berberine on oxidative stress-related signaling pathways nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1), hypoxia-inducible factor-1α (HIF-1α), and epithelial-mesenchymal transition (EMT) was assessed through Western blot analysis.

Results

Network pharmacology analysis identified 281 targets for berberine and 8,953 targets related to GC, revealing 224 common targets. GO enrichment analysis encompassed 3,001 biological processes, with the top 10 including responses to external biotic stimuli, oxidative stress, nutrient levels, chemical stress, oxygen levels, and hypoxia. Additionally, 122 cellular components and 213 molecular functions were identified. KEGG pathway enrichment analysis indicated 176 related signaling pathways, with key pathways for berberine's anti-GC effects potentially including phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT), forkhead box O (FOXO), and HIF-1. In vitro experiments demonstrated that berberine significantly inhibited GC cell activity and migration, increased intracellular levels of ROS and MDA, reduced levels of SOD, and suppressed the expression of Nrf2/HO-1, HIF-1α, and EMT pathway proteins.

Conclusions

Regulation of oxidative stress may be one of the key mechanisms by which berberine inhibits the progression of gastric cancer.

Anti-oxidants as therapeutic agents for oxidative stress associated pathologies: future challenges and opportunities

Free radicals have been implicated in the pathogenesis of cancer along with cardiovascular, neurodegenerative, pulmonary and inflammatory disorders. Further, the relationship between oxidative stress and disease is distinctively established. Clinical trials using anti-oxidants for the prevention of disease progression have indicated some beneficial effects. However, these trials failed to establish anti-oxidants as therapeutic agents due to lack of efficacy. This is attributed to the fact that living systems are under dynamic redox control wherein their redox behavior is compartmentalized and simple aggregation of redox couples, distributed throughout the system, is of miniscule importance while determining their overall redox state. Further, free radical metabolism is intriguingly complex as they play plural roles segregated in a spatio-temporal manner. Depending on quality, quantity and site of generation, free radicals exhibit beneficial or harmful effects. Use of nonspecific, non-targeted, general ROS scavengers lead to systemic elimination of all types of ROS and interferes in cellular signaling. Failure of anti-oxidants to act as therapeutic agents lies in this oversimplification of extremely dynamic cellular redox environment as a static and non-compartmentalized redox state. Rather than generalizing the term "oxidative stress" if we can identify the "type of oxidative stress" in different types of diseases, a targeted and more specific anti-oxidant therapy may be developed. In this review, we discuss the concept of redox dynamics, role and type of oxidative stress in disease conditions, and current status of anti-oxidants as therapeutic agents. Further, we probe the possibility of developing novel, targeted and efficacious anti-oxidants with drug-like properties.

Effect of Motor Activity Restriction on Copper Content in Rats

In rats subjected to increasing restriction of motor activity starting from day 21 days of life, copper content was evaluated by electron paramagnetic resonance (EPR) spectroscopy by analyzing the levels of copper-containing paramagnetic complexes in the heart and liver tissues. Copper content was assessed by the intensity of the characteristic EPR signal from the Cu2+-diethyldithiocarbamate complex (Cu2+-(DETC)2). It was found that after restriction of motor activity for 30 days, copper content in the heart and liver tissues increased by 2.2 and 2.9 times, respectively.

Protective effects of quercetin against tongue injury and oxidative stress triggered by irinotecan: a histopathological, biochemical and molecular study

Introduction

About 80% of patients receiving chemotherapeutics suffer from side effects related to the gastrointestinal tract. Irinotecan (CPT-11) is a chemotherapeutic agent usually used in treating solid tumors. Quercetin (QRT), a bioflavonoid, is an antioxidant and scavenger reactive oxygen species scavenger.

Objective

The current study explored the possible protective effects of QRT against mucosal tongue injury caused by CPT-11.

Methods

The study included four equal groups: group 1/control, group 2/QRT, group 3/CPT-11, and group 4/CPT-11 + QRT.

Results

CPT-11-induced tongue injury in the form of non-healed ulcers, absent lingual papillae, mononuclear cells infiltration, marked deposition of collagen fibers, and overexpression of CD86 and tumor necrosis factor- α (TNF-α). The increased malondialdehyde levels, decreased superoxide dismutase and total antioxidant capacity revealed that there was an oxidative stress. Also, there was a decreased countenance of Ki-67 and Bcl-2 and an increased countenance of NF-κB. The QRT-treated group showed complete ulcer healing, with histological features almost like the control group, along with minimal collagen fiber deposition, decreased reactivity to CD86 and TNF-α and improvement of oxidative stress status and the molecular study results as well.

Conclusion

QRT possess protective properties against CPT-11-triggered tongue injury.

Genomic and transcriptomic analyses reveal insights into cadmium resistance mechanisms of Cupriavidus nantongensis strain E324

The cadmium-resistant Cupriavidus sp. strain E324 has been previously shown to have a high potential for use in cadmium (Cd) remediation, due to its high capacity for cadmium bioaccumulation. According to the comparative genomic analysis, the strain E324 was most closely related to C. nantongensis X1T, indicating that the strain E324 should be re-identified as C. nantongensis. To unravel the Cd tolerance mechanisms of C. nantongensis strain E324, the transcriptional response of this strain to acute Cd exposure was assessed using RNA-seq-based transcriptome analysis, followed by validation through qRT-PCR. The results showed that the upregulated Differentially Expressed Genes (DEGs) were significantly enriched in categories related to metal binding and transport, phosphate transport, and oxidative stress response. Consistently, we observed significant increases in both the cell wall and intracellular contents of certain essential metals (Cu, Fe, Mn, and Zn) upon Cd exposure. Among these, only the Zn pretreatment resulting in high Zn accumulation in the cell walls could enhance bacterial growth under Cd stress conditions through its role in inhibiting Cd accumulation. Additionally, the promotion of catalase activity and glutathione metabolism upon Cd exposure to cope with Cd-induced oxidative stress was demonstrated. Meanwhile, the upregulation of phosphate transport-related genes upon Cd treatment seems to be the bacterial response to Cd-induced phosphate depletion. Altogether, our findings suggest that these adaptive responses are critical mechanisms contributing to increased Cd tolerance in C. nantongensis strain E324 via the enhancement of metal-chelating and antioxidant capacities of the cells.

Acute and prolonged effects of Bacillus amyloliquefaciens GF424-derived SOD on antioxidant defense in healthy individuals challenged with intense aerobic exercise

Reactive oxygen species (ROS) play a vital role in cellular functions but can lead to oxidative stress and contribute to degenerative diseases when produced in excess. Maintaining redox balance is essential and can be achieved through innate defense mechanisms or external antioxidants. Superoxide dismutase (SOD) is a key enzyme that mitigates intracellular oxidative stress by converting harmful free radicals into hydrogen peroxide, which is subsequently neutralized by catalase and glutathione peroxidase. Previous studies have demonstrated the antioxidant capabilities of SOD derived from Bacillus amyloquefaciens GF424 (BA-SOD) in murine models exposed to either irradiation or SOD1 gene deletion. In this study, a randomized clinical trial was conducted to evaluate the antioxidative benefits of BA-SOD in healthy individuals undergoing acute aerobic exercise (AAE). Eighty participants were randomly assigned to receive either BA-SOD or a placebo for 8 weeks. Antioxidant enzyme activities and glutathione levels were measured before, immediately after, and 30 min post-exercise. A single dose of BA-SOD significantly reduced ROS levels induced by AAE, primarily by enhancing SOD activity in erythrocytes and activating glutathione peroxidase. Continuous BA-SOD administration was associated with a sustained increase in catalase activity and elevated levels of reduced glutathione (GSH). Transcriptomic and metabolomic analyses revealed that a single BA-SOD dose facilitated GSH oxidation, as evidenced by decreased levels of serine, glutamine, and glycine, and increased pyroglutamate levels. Additionally, repeated dosing led to increased expression of genes encoding isocitrate dehydrogenase and malic enzyme, which are involved in NADPH synthesis, as well as nicotinamide phosphoribosyl transferase and NAD kinase, which are essential for NADP availability-critical for converting oxidized glutathione (GSSG) back to GSH. These molecular insights align with clinical observations, suggesting that both acute and long-term BA-SOD supplementation may effectively enhance antioxidant defenses and maintain redox balance under oxidative stress conditions.

Early-Branching Cyanobacteria Grow Faster and Upregulate Superoxide Dismutase Activity Under a Simulated Early Earth Anoxic Atmosphere

The evolution of oxygenic photosynthesis during the Archean (4-2.5 Ga) required the presence of complementary reducing pathways to maintain the cellular redox balance. While the timing of the evolution of superoxide dismutases (SODs), enzymes that convert superoxide to hydrogen peroxide and O2, within bacteria and archaea is not resolved, the first SODs appearing in cyanobacteria contained copper and zinc in the reaction center (CuZnSOD). Here, we analyse growth characteristics, SOD gene expression (qRT-PCR) and cellular enzyme activity in the deep branching strain, Pseudanabaena sp. PCC7367, previously demonstrated to release significantly more O2 under anoxic conditions. The observed significantly higher growth rates (p < 0.001) and protein and glycogen contents (p < 0.05) in anoxically cultured Pseudanabaena PCC7367 compared to control cultures grown under present-day oxygen-rich conditions prompted the following question: Is the growth of Pseudanabaena sp. PCC7367 correlated to atmospheric pO2 and cellular SOD activity? Expression of sodB (encoding FeSOD) and sodC (encoding CuZnSOD) strongly correlated with medium O2 levels (p < 0.001). Expression of sodA (encoding MnSOD) correlated significantly to SOD activity during the day (p = 0.019) when medium O2 concentrations were the highest. The cellular SOD enzyme activity of anoxically grown cultures was significantly higher (p < 0.001) 2 h before the onset of the dark phase compared to O2-rich growth conditions. The expression of SOD encoding genes was significantly reduced (p < 0.05) under anoxic conditions in stirred cultures, as were medium O2 levels (p ≤ 0.001), compared to oxic-grown cultures, whereas total cellular SOD activity remained comparable. Our data suggest that increasing pO2 negatively impacts the viability of early cyanobacteria, possibly by increasing photorespiration. Additionally, the increased expression of superoxide-inactivating genes during the dark phase suggests the increased replacement rates of SODs under modern-day conditions compared to those on early Earth.

On the genesis and unique functions of zinc neuromodulation

In addition to the essential structural and catalytic functions of zinc, evolution has adopted synaptic zinc as a neuromodulator. In the brain, synaptic zinc is released primarily from glutamatergic neurons, notably in the neocortex, hippocampus, amygdala, and auditory brainstem. In these brain areas, synaptic zinc is essential for neuronal and sensory processing fine-tuning. But what niche does zinc fill in neural signaling that other neuromodulators do not? Here, we discuss the evolutionary history of zinc as a signaling agent and its eventual adoption as an essential neuromodulator in the mammalian brain. We then attempt to describe the unique roles that zinc has carved out of the vast and diverse landscape of neuromodulators.

Regulation of the SIRT3/SOD2 Signaling Pathway by a Compound Mixture from Polygonum orientale L. for Myocardial Damage

BACKGROUND

Polygonum orientale L. (PO) has demonstrated notable efficacy in treating coronary heart disease. Previous research identified eight key active components in PO for cardiomyocyte protection, but the underlying mechanisms remained unclear; Methods: Network pharmacology and molecular docking were used to identify potential target proteins of PO's active components. Experimental models assessed the cardioprotective effects and mechanisms; Results: Network analysis and molecular docking revealed that the active components exhibited the highest binding affinity with SOD2, indicating it as a key element in the cardiac protection of PO. In vivo, PO extract improved myocardial structure and function, and increased SOD2 protein levels. In vitro, the active components of PO (Mixture) mitigated oxidative stress and apoptosis, upregulating SIRT3 and decreasing acetylated SOD2, leading to increased SOD2 and reduced ROS levels. The observed effects were reversed by a SIRT3 inhibitor, indicating the involvement of the SIRT3/SOD2 signaling pathway; Conclusions: This comprehensive approach elucidated the critical mechanisms underlying the cardioprotective properties of PO's bioactive constituents, highlighting the regulation of the SIRT3/SOD2 signaling pathway as a new mechanism for PO's anti-cardiovascular disease effects, and suggesting the Mixture's potential as a promising drug candidate.

Current potential pathogenic mechanisms of copper-zinc superoxide dismutase 1 (SOD1) in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease which damages upper and lower motor neurons (UMN and LMN) innervating the muscles of the trunk, extremities, head, neck and face in cerebrum, brain stem and spinal cord, which results in the progressive weakness, atrophy and fasciculation of muscle innervated by the related UMN and LMN, accompanying with the pathological signs leaded by the cortical spinal lateral tract lesion. The pathogenesis about ALS is not fully understood, and no specific drugs are available to cure and prevent the progression of this disease at present. In this review, we reviewed the structure and associated functions of copper-zinc superoxide dismutase 1 (SOD1), discuss why SOD1 is crucial to the pathogenesis of ALS, and outline the pathogenic mechanisms of SOD1 in ALS that have been identified at recent years, including glutamate-related excitotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, oxidative stress, axonal transport disruption, prion-like propagation, and the non-cytologic toxicity of glial cells. This review will help us to deeply understand the current progression in this field of SOD1 pathogenic mechanisms in ALS.

Alleviation of arsenic stress in pakchoi by foliar spraying of engineered nanomaterials

Addressing heavy metal contamination in leafy vegetables is critically important due to its adverse effects on human health. In this study, we investigated the inhibitory effects of foliar spraying with four nanoparticles (CeO2, ZnO, SiO2, and S NPs) on arsenic (As) stress in pakchoi (Brassica rapa var. Chinensis). The findings reveal that foliar application of ZnO NPs at 1 ~ 2.5 mg plant-1 and CeO2 NPs at 5 mg plant-1 significantly reduces As in shoots by 40.9 ~ 47.3% and 39.4%, respectively. Moreover, 5 mg plant-1 CeO2 NPs increased plant height by 6.06% and chlorophyll a (Chla) content by 30.2% under As stress. Foliar spraying of CeO2 NPs at 0.2-5 mg plant-1 also significantly enhanced superoxide dismutase (SOD) activity in shoots by 9.4 ~ 13.9%, lowered H2O2 content by 42.4 ~ 53.25%, and increased root protein contents by 79 ~ 109.2%. CeO2 NPs regulate the As(III)/As(V) ratio, aiding in As efflux from roots and thereby reducing As toxicity to plants. In vitro digestion experiments reveal that the consumption of CeO2 NPs carries the lowest health risk of As. In addition, foliar spraying of ZnO NPs at 1 ~ 2.5 mg plant-1 can suppress plant As uptake by modulating enzyme activity, reducing leaf damage, and enhancing chlorophyll content. The study demonstrates that high CeO2 NP concentrations and suitable ZnO NP concentrations can alleviate As toxicity in pakchoi, consequently reducing human health risks.

The Scavenging Activity of Coenzyme Q10 Plus a Nutritional Complex on Human Retinal Pigment Epithelial Cells

Age-related macular degeneration (AMD) and diabetic retinopathy (DR) are common retinal diseases responsible for most blindness in working-age and elderly populations. Oxidative stress and mitochondrial dysfunction play roles in these pathogenesis, and new therapies counteracting these contributors could be of great interest. Some molecules, like coenzyme Q10 (CoQ10), are considered beneficial to maintain mitochondrial homeostasis and contribute to the prevention of cellular apoptosis. We investigated the impact of adding CoQ10 (Q) to a nutritional antioxidant complex (Nutrof Total®; N) on the mitochondrial status and apoptosis in an in vitro hydrogen peroxide (H2O2)-induced oxidative stress model in human retinal pigment epithelium (RPE) cells. H2O2 significantly increased 8-OHdG levels (p < 0.05), caspase-3 (p < 0.0001) and TUNEL intensity (p < 0.01), and RANTES (p < 0.05), caspase-1 (p < 0.05), superoxide (p < 0.05), and DRP-1 (p < 0.05) levels, and also decreased IL1β, SOD2, and CAT gene expression (p < 0.05) vs. control. Remarkably, Q showed a significant recovery in IL1β gene expression, TUNEL, TNFα, caspase-1, and JC-1 (p < 0.05) vs. H2O2, and NQ showed a synergist effect in caspase-3 (p < 0.01), TUNEL (p < 0.0001), mtDNA, and DRP-1 (p < 0.05). Our results showed that CoQ10 supplementation is effective in restoring/preventing apoptosis and mitochondrial stress-related damage, suggesting that it could be a valid strategy in degenerative processes such as AMD or DR.

The "Sunshine Vitamin" and Its Antioxidant Benefits for Enhancing Muscle Function

Pathological states marked by oxidative stress and systemic inflammation frequently compromise the functional capacity of muscular cells. This progressive decline in muscle mass and tone can significantly hamper the patient's motor abilities, impeding even the most basic physical tasks. Muscle dysfunction can lead to metabolic disorders and severe muscle wasting, which, in turn, can potentially progress to sarcopenia. The functionality of skeletal muscle is profoundly influenced by factors such as environmental, nutritional, physical, and genetic components. A well-balanced diet, rich in proteins and vitamins, alongside an active lifestyle, plays a crucial role in fortifying tissues and mitigating general weakness and pathological conditions. Vitamin D, exerting antioxidant effects, is essential for skeletal muscle. Epidemiological evidence underscores a global prevalence of vitamin D deficiency, which induces oxidative harm, mitochondrial dysfunction, reduced adenosine triphosphate production, and impaired muscle function. This review explores the intricate molecular mechanisms through which vitamin D modulates oxidative stress and its consequent effects on muscle function. The aim is to evaluate if vitamin D supplementation in conditions involving oxidative stress and inflammation could prevent decline and promote or maintain muscle function effectively.

In silico identification and expression analysis of superoxide dismutases in Tenebrio molitor

BACKGROUND

Insects encounter various environmental stresses, in response to which they generate reactive oxygen species (ROS). Superoxide dismutase (SOD) is an antioxidant metalloenzyme that scavenges superoxide radicals to prevent oxidative damage.

OBJECTIVE

To investigate expressions of SODs under oxidative stress in Tenebrio molitor.

METHODS

Here, we investigated the transcriptional expression of SODs by pesticide and heavy metals in Tenebrio moltior. First, we searched an RNA-Seq database for T. molitor SOD (TmSOD) genes and identified two SOD isoforms (TmSOD1-iso1 and iso2). We examined their activities under developmental stage, tissue-specific, and various types (pesticide and heavy metal) of oxidative stress by using qPCR.

RESULTS

Our results revealed two novel forms of TmSODs. These TmSODs had a copper/zinc superoxide dismutase domain, active site, Cu2+ binding site, Zn2+ binding site, E-class dimer interface, and P-class dimer interface. TmSODs (TmSOD1-iso1 and iso2) were expressed in diverse developmental phases and tissues. Pesticides and heavy metals caused an upregulation of these TmSODs.

CONCLUSION

Our findings suggest that the two TmSODs have different functions in T. molitor, providing insights into the detoxification ability of T. molitor.

Antioxidant Systems of Plant Pathogenic Fungi: Functions in Oxidative Stress Response and Their Regulatory Mechanisms

During the infection process, plant pathogenic fungi encounter plant-derived oxidative stress, and an appropriate response to this stress is crucial to their survival and establishment of the disease. Plant pathogenic fungi have evolved several mechanisms to eliminate oxidants from the external environment and maintain cellular redox homeostasis. When oxidative stress is perceived, various signaling transduction pathways are triggered and activate the downstream genes responsible for the oxidative stress response. Despite extensive research on antioxidant systems and their regulatory mechanisms in plant pathogenic fungi, the specific functions of individual antioxidants and their impacts on pathogenicity have not recently been systematically summarized. Therefore, our objective is to consolidate previous research on the antioxidant systems of plant pathogenic fungi. In this review, we explore the plant immune responses during fungal infection, with a focus on the generation and function of reactive oxygen species. Furthermore, we delve into the three antioxidant systems, summarizing their functions and regulatory mechanisms involved in oxidative stress response. This comprehensive review provides an integrated overview of the antioxidant mechanisms within plant pathogenic fungi, revealing how the oxidative stress response contributes to their pathogenicity.

Adaptive evolution of antioxidase-related genes in hypoxia-tolerant mammals

To cope with the damage from oxidative stress caused by hypoxia, mammals have evolved a series of physiological and biochemical traits, including antioxidant ability. Although numerous research studies about the mechanisms of hypoxia evolution have been reported, the molecular mechanisms of antioxidase-related genes in mammals living in different environments are yet to be completely understood. In this study, we constructed a dataset comprising 7 antioxidase-related genes (CAT, SOD1, SOD2, SOD3, GPX1, GPX2, and GPX3) from 43 mammalian species to implement evolutionary analysis. The results showed that six genes (CAT, SOD1, SOD2, SOD3, GPX1, and GPX3) have undergone divergent evolution based on the free-ratio (M1) model. Furthermore, multi-ratio model analyses uncovered the divergent evolution between hypoxic and non-hypoxic lineages, as well as various hypoxic lineages. In addition, the branch-site model identified 9 positively selected branches in 6 genes (CAT, SOD1, SOD2, SOD3, GPX2, and GPX3) that contained 35 positively selected sites, among which 31 positively selected sites were identified in hypoxia-tolerant branches, accounting for 89% of the total number of positively selected sites. Interestingly, 65 parallel/convergent sites were identified in the 7 genes. In summary, antioxidase-related genes are subjected to different selective pressures among hypoxia-tolerant species living in different habitats. This study provides a valuable insight into the molecular evolution of antioxidase-related genes in hypoxia evolution in mammals.

Protection against Oxidative Stress by Coenzyme Q10 in a Porcine Retinal Degeneration Model

Oxidative stress plays an important role in neurodegenerative diseases, including glaucoma. Therefore, we analyzed if the antioxidant coenzyme Q10 (CoQ10), which is also commercially available, can prevent retinal degeneration induced by hydrogen peroxide (H2O2) in a porcine organ culture model. Retinal explants were cultivated for eight days, and H2O2 (500 µM, 3 h) induced the oxidative damage. CoQ10 therapy was applied (700 µM, 48 h). Retinal ganglion cells (RGCs) and microglia were examined immunohistologically in all groups (control, H2O2, H2O2 + CoQ10). Cellular, oxidative, and inflammatory genes were quantified via RT-qPCR. Strong RGC loss was observed with H2O2 (p ≤ 0.001). CoQ10 elicited RGC protection compared to the damaged group at a histological (p ≤ 0.001) and mRNA level. We detected more microglia cells with H2O2, but CoQ10 reduced this effect (p = 0.004). Cellular protection genes (NRF2) against oxidative stress were stimulated by CoQ10 (p ≤ 0.001). Furthermore, mitochondrial oxidative stress (SOD2) increased through H2O2 (p = 0.038), and CoQ10 reduced it to control level. Our novel results indicate neuroprotection via CoQ10 in porcine retina organ cultures. In particular, CoQ10 appears to protect RGCs by potentially inhibiting apoptosis-related pathways, activating intracellular protection and reducing mitochondrial stress.

Superoxidase dismutases (SODs) in the European eel: Gene characterization, expression response to temperature combined with hormonal maturation and possible migratory implications

Superoxide dismutases (SODs) are antioxidant enzymes that protect cells from oxidation. Three SODs have been identified in mammals, but there is limited information in teleosts. This study investigates SODs in the European eel and their expression patterns during testis maturation. Phylogenetic and synteny analyses revealed SODs paralogs and their evolution in vertebrates. The eel possesses one SOD1 and two SOD2/3 (a and b), indicating SOD2 and SOD3 duplication in elopomorphs. SODs expression were then evaluated in various male and female tissues. SOD1 is more expressed in females, while SOD2a and SOD2b dominate brain-pituitary-gonad tissues in both sexes. SOD3a showed predominant expression in the ovary and the male livers, whereas SOD3b was found in the pituitary and brain of both sexes. The effects of different maturation protocols (standard hormonal treatment vs. same protocol preceded with cold seawater pre-treatment) on SODs expression during testis maturation were evaluated. Salinity increase at the onset of standard treatment at 20 °C, simulating early migration, upregulated SOD1, SOD2a, and SOD2b, coinciding with spermatogonia type A differentiated cells dominance. Thereafter, SOD2a and SOD3a decreased, while SOD2b increased during hormonal treatment-induced spermatogenesis. Pre-treatment with seawater at 10 °C, mimicking the conditions at the beginning of the seawater migration, downregulated SOD1 but increased SOD3a expression. Finally, the standard hormonal treatment, replicating spawning at higher temperatures, downregulated SOD1 in eels without any pre-treatment while SOD2a expression increased in pre-treated eels. This study revealed tissue-specific, sex-dependent, and maturation-related SOD expression patterns, predicting SODs dynamic expression profiles during their reproductive migration.

Transcriptional regulation of the Japanese flounder Cu,Zn-SOD (Jfsod1) gene in RAW264.7 cells during oxidative stress caused by causative bacteria of edwardsiellosis

Edwardsiellosis is one of the most important bacterial diseases in fish, sometimes causing extensive economic losses in the aquaculture industry. Our previous studies demonstrated that the Cu,Zn-SOD (sod1) activity has significantly increased in Japanese flounder, Paralichthys olivaceus, hepatopancreas infected by causative bacteria of edwardsiellosis Edwardsiella tarda NUF251. In this study, NUF251 stimulated intracellular superoxide radical production in mouse macrophage RAW264.7 cells, which was reduced by N-acetylcysteine. This result suggests that NUF251 infection causes oxidative stress. To evaluate the regulatory mechanism of Jfsod1 at transcriptional levels under oxidative stress induced by NUF251 infection, we cloned and determined the nucleotide sequence (1124 bp) of the 5'-flanking region of the Jfsod1 gene. The sequence analysis demonstrated that the binding sites for the transcription factors C/EBPα and NF-IL6 involved in the transcriptional regulation of the mammalian sod1 gene existed. We constructed a luciferase reporter system with the 5'-flanking region (-1124/-1) of the Jfsod1 gene, and a highly increased transcriptional activity of the region was observed in NUF251-infected RAW264.7 cells. Further studies using several mutants indicated that deletion of the recognition region of NF-IL6 (-272/-132) resulted in a significant decrease in the transcriptional activity of the Jfsod1 gene in NUF251-infected RAW264.7 cells. In particular, the binding site (-202/-194) for NF-IL6 might play a major role in upregulating the transcriptional activity of the 5'-flanking region of the Jfsod1 gene in response to oxidative stress induced by NUF251 infection. These results could be provided a new insight to understand the pathogenic mechanism of causative bacteria of edwardsiellosis.

Nondestructive Evaluation of Metal Bioaccumulation and Biochemical Biomarkers in Blood of Broad-Snouted Caiman (Caiman latirostris) from Northeastern Brasil

Studies on the bioaccumulation and toxicity of contaminants in Crocodylians are scarce. We evaluated alterations in concentrations of the nondestructive biomarkers butyrylcholinesterase (BChE), glutathione-S-transferase (GST), superoxide dismutase (SOD), and reduced glutathione (GSH), together with bioaccumulation of the metals iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), chronium (Cr), aluminium (Al), and lead (Pb) in Caiman latirostris captured in Tapacurá Reservoir (TR; São Lourenço da Mata, Pernambuco, Brasil), in urbanized areas of Pernambuco State (UA; Brasil) and from the AME Brasil caiman farm (AF; Marechal Deodoro, Alagoas, Brasil); the latter was used as a potential reference with low levels of contamination. For metal analysis, 500 µL of blood was digested in 65% HNO3 and 30% H2 O2 . The samples were analyzed by inductively coupled plasma-optical emission spectrometry. For analysis of biomarkers, an aliquot of blood was centrifuged to obtain plasma in which biochemical assays were performed. Blood concentrations of metals analyzed in animals from AF were lower compared with TR and UA, confirming that animals from the caiman farm could be used as references with low levels of contamination. Iron, Cu, Mn, Al, and Pb exceeded toxic levels for other vertebrates in animals from TR and UA. Butyrylcholinesterase activity showed significant reduction in adults from UA and TR compared with AF. An increase in the activity of GST and GSH, in adults of TR and UA in relation to AF, was verified. Superoxide dismutase activity showed a significant reduction in adults of TR in relation to AF, and the concentrations of Cu and Mn were negatively correlated with SOD activity. Animals from UA and TR showed greater concentrations of the analyzed metals compared with reference animals, and changes in biomarkers were seen, confirming the potential of these nondestructive chemical and biological parameters in blood of C. latirostris for biomonitoring of pollution. Environ Toxicol Chem 2024;00:1-18. © 2024 SETAC.

Oxidative stress related effect of xenobiotics on eukaryotic model organism, Saccharomyces cerevisiae

Ecotoxicological assays have traditionally focused on the effects of chemicals at the individual level by exploiting mortality and reproduction as endpoints. Although these two parameters are ecologically relevant, they rarely provide information regarding the elemental toxic mechanisms. Obviously, the number of xenobiotics used has been rapidly increased. Thus, any established measurement that shortens the actual outcome and, simultaneously provides information about toxic mechanisms is desirable. This research focused on the study of oxidative stress response as a biomarker in the eukaryotic model organism, Saccharomyces cerevisiae. For this, yeast cells were exposed to a set of selected environmentally relevant chemicals via different approaches, including cellular diagnostics, gene expression analysis and chemo-genetic screening. The results demonstrated that at the cellular level, model organisms reacted to different chemicals in distinct manner. For each xenobiotic, the correlation between toxic response of molecular and cellular levels are presented. Namely, the expression of target genes after chemical exposure affected the cellular alteration as evidenced by an elevated level of superoxide dismutase and a reduced amount of glutathione. Furthermore, the results derived from chemo-genetic screening, in which mutants lacking of gene of interest were employed, exhibited more susceptibility to test chemicals in comparison to the wildtype. The response of oxidative stress upon chemical exposure in budding yeast from this study is potentially useful for an establishment of a proper bio-test system which can eventually be linked to adverse effects at an individual level in higher eukaryotes.

Thirty years with three-dimensional structures of lipoxygenases

The X-ray crystal structures of soybean lipoxygenase (LOX) and rabbit 15-LOX were reported in the 1990s. Subsequent 3D structures demonstrated a conserved U-like shape of the substrate cavities as reviewed here. The 8-LOX:arachidonic acid (AA) complex showed AA bound to the substrate cavity carboxylate-out with C10 at 3.4 Å from the iron metal center. A recent cryo-electron microscopy (EM) analysis of the 12-LOX:AA complex illustrated AA in the same position as in the 8-LOX:AA complex. The 15- and 12-LOX complexes with isoenzyme-specific inhibitors/substrate mimics confirmed the U-fold. 5-LOX oxidizes AA to leukotriene A4, the first step in biosynthesis of mediators of asthma. The X-ray structure showed that the entrance to the substrate cavity was closed to AA by Phe and Tyr residues of a partly unfolded α2-helix. Recent X-ray analysis revealed that soaking with inhibitors shifted the short α2-helix to a long and continuous, which opened the substrate cavity. The α2-helix also adopted two conformations in 15-LOX. 12-LOX dimers consisted of one closed and one open subunit with an elongated α2-helix. 13C-ENDOR-MD computations of the 9-MnLOX:linoleate complex showed carboxylate-out position with C11 placed 3.4 ± 0.1 Å from the catalytic water. 3D structures have provided a solid ground for future research.

Discovering Nature's shield: Metabolomic insights into green zinc oxide nanoparticles Safeguarding Brassica parachinensis L. from cadmium stress

Heavy metal cadmium (Cd) hinders plants' growth and productivity by causing different morphological and physiological changes. Nanoparticles (NPs) are promising for raising plant yield and reducing Cd toxicity. Nonetheless, the fundamental mechanism of nanoparticle-interfered Cd toxicity in Brassica parachineses L. remains unknown. A novel ZnO nanoparticle (ZnO-NPs) was synthesized using a microalgae strain (Chlorella pyrenoidosa) through a green process and characterized by different standard parameters through TEM, EDX, and XRD. This study examines the effect of different concentrations of ZnO-NPs (50 and 100 mgL-1) in B. parachineses L. under Cd stress through ultra-high-performance liquid chromatography/high-resolution mass spectrometry-based untargeted metabolomics profiling. In the presence of Cd toxicity, foliar spraying with ZnO-NPs raised Cu, Fe, Zn, and Mg levels in the roots and/or leaves, improved seedling development, as demonstrated by increased plant height, root length, and shoot and root fresh weight. Furthermore, the ZnO-NPs significantly enhanced the photosynthetic pigments and changed the antioxidant activities of the Cd-treated plants. Based on a metabolomics analysis, 481 untargeted metabolites were accumulated in leaves under normal and Cd-stressed conditions. These metabolites were highly enriched in producing organic acids, amino acids, glycosides, flavonoids, nucleic acids, and vitamin biosynthesis. Surprisingly, ZnO-NPs restored approximately 60% of Cd stress metabolites to normal leaf levels. Our findings suggest that green synthesized ZnO-NPs can balance ions' absorption, modulate the antioxidant activities, and restore more metabolites associated with plant growth to their normal levels under Cd stress. It can be applied as a plant growth regulator to alleviate heavy metal toxicity and improve crop yield in heavy metal-contaminated regions.

How a natural antibiotic uses oxidative stress to kill oxidant-resistant bacteria

Natural products that possess antibiotic and antitumor qualities are often suspected of working through oxidative mechanisms. In this study, two quinone-based small molecules were compared. Menadione, a classic redox-cycling compound, was confirmed to generate high levels of reactive oxygen species inside Escherichia coli. It inactivated iron-cofactored enzymes and blocked growth. However, despite the substantial levels of oxidants that it produced, it was unable to generate significant DNA damage and was not lethal. Streptonigrin, in contrast, was poorer at redox cycling and did not inactivate enzymes or block growth; however, even in low doses, it damaged DNA and killed cells. Its activity required iron and oxygen, and in vitro experiments indicated that its quinone moiety transferred electrons through the adjacent iron atom to oxygen. Additionally, in vitro experiments revealed that streptonigrin was able to damage DNA without inhibition by catalase, indicating that hydrogen peroxide was not involved. We infer that streptonigrin can reduce bound oxygen directly to a ferryl species, which then oxidizes the adjacent DNA, without release of superoxide or hydrogen peroxide intermediates. This scheme allows streptonigrin to kill a bacterial cell without interference by scavenging enzymes. Moreover, its minimal redox-cycling behavior avoids alerting either the OxyR or the SoxRS systems, which otherwise would block killing. This example highlights qualities that may be important in the design of oxidative drugs. These results also cast doubt on proposals that bacteria can be killed by stressors that merely stimulate intracellular O2- and H2O2 formation.

The Mar, Sox, and Rob Systems

Environments inhabited by Enterobacteriaceae are diverse and often stressful. This is particularly true for Escherichia coli and Salmonella during host association in the gastrointestinal systems of animals. There, E. coli and Salmonella must survive exposure to various antimicrobial compounds produced or ingested by their host. A myriad of changes to cellular physiology and metabolism are required to achieve this feat. A central regulatory network responsible for sensing and responding to intracellular chemical stressors like antibiotics are the Mar, Sox, and Rob systems found throughout the Enterobacteriaceae. Each of these distinct regulatory networks controls expression of an overlapping set of downstream genes whose collective effects result in increased resistance to a wide array of antimicrobial compounds. This collection of genes is known as the mar-sox-rob regulon. This review will provide an overview of the mar-sox-rob regulon and molecular architecture of the Mar, Sox, and Rob systems.

Direct relationship between dimeric form and activity in the acidic copper-zinc superoxide dismutase from lemon

The copper-zinc superoxide dismutase (CuZnSOD) from lemon (SOD_CL) is active in an acidic environment and resists proteolytic degradation. The enzyme occurs as a dimer, which has an indirect effect on the enzyme activity as the monomer retains only ∼35% of the activity. Here, the crystal structure of SOD_CL at 1.86 Å resolution is reported that may explain this peculiarity. The crystal belonged to space group P21, with unit-cell parameters a = 61.11, b = 74.55, c = 61.69 Å, β = 106.86°, and contained four molecules in the asymmetric unit. The overall structure of SOD_CL resembles that of CuZnSOD from plants. The structure of SOD_CL shows a unique arrangement of surface loop IV that connects the dimer interface and the active site, which is located away from the dimer-interface region. This arrangement allows direct interaction between the residues residing in the dimer interface and those in the active site. The arrangement also includes Leu62 and Gln164, which are conserved in cytoplasmic CuZnSOD. This supports the classification of SOD_CL as a cytoplasmic CuZnSOD despite sharing the highest amino-acid sequence homology with CuZnSODs from spinach and tomato, which are chloroplastic.

Physiological and metabolomic analyses reveal that Fe3O4 nanoparticles ameliorate cadmium and arsenic toxicity in Panax notoginseng

Heavy metal(loid)-contaminated available arable land seriously affects crop development and growth. Engineered nanomaterials have great potential in mitigating toxic metal(loid) stress in plants. However, there are few details of nanoparticles (NPs) involved in Panax notoginseng response to cadmium (Cd) and arsenic (As). Herein, integrating physiological and metabolomic analyses, we investigated the effects of Fe3O4 NPs on plant growth and Cd/As responses in P. notoginseng. Cd/As treatment caused severe growth inhibition. However, foliar application of Fe3O4 NPs increased beneficial elements in the roots and/or leaves, decreased Cd/As content by 10.38% and 20.41% in the roots, reduced membrane damage and regulated antioxidant enzyme activity, thereby alleviating Cd/As-induced growth inhibition, as indicated by increased shoot fresh weight (FW), the rootlet length and root FW by 40.14%, 15.74%, and 46.70% under Cd stress and promoted the shoot FW by 27.00% under As toxicity. Metabolomic analysis showed that 227 and 295 differentially accumulated metabolites (DAMs) were identified, and their accumulation patterns were classified into 8 and 6 clusters in the roots and leaves, respectively. Fe3O4 NPs altered metabolites significantly involved in key pathways, including amino sugar and nucleotide sugar metabolism, flavonoid biosynthesis and phenylalanine metabolism, thus mediating the trade-off between plant growth and defense under stress. Interestingly, Fe3O4 NPs recovered more Cd/As-induced DAMs to normal levels, further supporting that Fe3O4 NPs positively affected seedling growth under metal(loid)s stress. In addition, Fe3O4 NPs altered terpenoids when the seedlings were subjected to Cd/As stress, thus affecting their potential medicinal value. This study provides insights into using nanoparticles to improve potential active ingredients of medicinal plants in metal(loid)-contaminated areas.

In vitro maturation of NiSOD reveals a role for cytoplasmic histidine in processing and metalation

The importance of cellular low molecular weight ligands in metalloenzyme maturation is largely unexplored. Maturation of NiSOD requires post-translational N-terminal processing of the proenzyme, SodN, by its cognate protease, SodX. Here we provide evidence for the participation of L-histidine in the protease-dependent maturation of nickel-dependent superoxide dismutase (NiSOD) from Streptomyces coelicolor. In vitro studies using purified proteins cloned from S. coelicolor and overexpressed in E. coli support a model where a ternary complex formed between the substrate (SodN), the protease (SodX) and L-Histidine creates a novel Ni-binding site that is capable of the N-terminal processing of SodN and specifically incorporates Ni into the apo-NiSOD product. Thus, L-Histidine serves many of the functions associated with a metallochaperone or, conversely, eliminates the need for a metallochaperone in NiSOD maturation.

Investigation of NO Role in Neural Tissue in Brain and Spinal Cord Injury

Nitric oxide (NO) production in injured and intact brain regions was compared by EPR spectroscopy in a model of brain and spinal cord injury in Wistar rats. The precentral gyrus of the brain was injured, followed by the spinal cord at the level of the first lumbar vertebra. Seven days after brain injury, a reduction in NO content of 84% in injured brain regions and 66% in intact brain regions was found. The difference in NO production in injured and uninjured brain regions persisted 7 days after injury. The copper content in the brain remained unchanged one week after modeling of brain and spinal cord injury. The data obtained in the experiments help to explain the problems in the therapy of patients with combined brain injury.

Global Transcriptomic Changes Elicited by sodB Deletion and Menadione Exposure in Aspergillus nidulans

Manganese superoxide dismutases (MnSODs) play a pivotal role in the preservation of mitochondrial integrity and function in fungi under various endogenous and exogenous stresses. Deletion of Aspergillus nidulans mnSOD/SodB increased oxidative stress sensitivity and apoptotic cell death rates as well as affected antioxidant enzyme and sterigmatocystin productions, respiration, conidiation and the stress tolerance of conidiospores. The physiological consequences of the lack of sodB were more pronounced during carbon starvation than in the presence of glucose. Lack of SodB also affected the changes in the transcriptome, recorded by high-throughput RNA sequencing, in menadione sodium bisulfite (MSB)-exposed, submerged cultures supplemented with glucose. Surprisingly, the difference between the global transcriptional changes of the ΔsodB mutant and the control strain were relatively small, indicating that the SodB-dependent maintenance of mitochondrial integrity was not essential under these experimental conditions. Owing to the outstanding physiological flexibility of the Aspergilli, certain antioxidant enzymes and endogenous antioxidants together with the reduction in mitochondrial functions compensated well for the lack of SodB. The lack of sodB reduced the growth of surface cultures more than of the submerged culture, which should be considered in future development of fungal disinfection methods.

Kaempferol Alleviates Mitochondrial Damage by Reducing Mitochondrial Reactive Oxygen Species Production in Lipopolysaccharide-Induced Prostate Organoids

Common prostate diseases such as prostatitis and benign prostatic hyperplasia (BPH) have a high incidence at any age. Cellular stresses, such as reactive oxygen species (ROS) and chronic inflammation, are implicated in prostate enlargement and cancer progression and development. Kaempferol is a flavonoid found in abundance in various plants, including broccoli and spinach, and has been reported to exhibit positive biological activities, such as antioxidant and anti-inflammatory properties. In the present study, we introduced prostate organoids to investigate the protective effects of kaempferol against various cellular stresses. The levels of COX-2, iNOS, p-IκB, a pro-inflammatory cytokine, and ROS were increased by LPS treatment but reversed by kaempferol treatment. Kaempferol activated the nuclear factor erythroid 2-related factor 2(Nrf2)-related pathway and enhanced the mitochondrial quality control proteins PGC-1α, PINK1, Parkin, and Beclin. The increase in mitochondrial ROS and oxygen consumption induced by LPS was stabilized by kaempferol treatment. First, our study used prostate organoids as a novel evaluation platform. Secondly, it was demonstrated that kaempferol could alleviate the mitochondrial damage in LPS-induced induced prostate organoids by reducing the production of mitochondrial ROS.

Chromosome-level genome assembly of Niphotrichum japonicum provides new insights into heat stress responses in mosses

With a diversity of approximately 22,000 species, bryophytes (hornworts, liverworts, and mosses) represent a major and diverse lineage of land plants. Bryophytes can thrive in many extreme environments as they can endure the stresses of drought, heat, and cold. The moss Niphotrichum japonicum (Grimmiaceae, Grimmiales) can subsist for extended periods under heat and drought conditions, providing a good candidate for studying the genetic basis underlying such high resilience. Here, we de novo assembled the genome of N. japonicum using Nanopore long reads combined with Hi-C scaffolding technology to anchor the 191.61 Mb assembly into 14 pseudochromosomes. The genome structure of N. japonicum's autosomes is mostly conserved and highly syntenic, in contrast to the sparse and disordered genes present in its sex chromosome. Comparative genomic analysis revealed the presence of 10,019 genes exclusively in N. japonicum. These genes may contribute to the species-specific resilience, as demonstrated by the gene ontology (GO) enrichment. Transcriptome analysis showed that 37.44% (including 3,107 unique genes) of the total annotated genes (26,898) exhibited differential expression as a result of heat-induced stress, and the mechanisms that respond to heat stress are generally conserved across plants. These include the upregulation of HSPs, LEAs, and reactive oxygen species (ROS) scavenging genes, and the downregulation of PPR genes. N. japonicum also appears to have distinctive thermal mechanisms, including species-specific expansion and upregulation of the Self-incomp_S1 gene family, functional divergence of duplicated genes, structural clusters of upregulated genes, and expression piggybacking of hub genes. Overall, our study highlights both shared and species-specific heat tolerance strategies in N. japonicum, providing valuable insights into the heat tolerance mechanism and the evolution of resilient plants.

Machine learning-aided metallomic profiling in serum and urine of thyroid cancer patients and its environmental implications

The incidence rate of thyroid cancer has been growing worldwide. Thyroid health is closely related with multiple trace metals, and the nutrients are essential in maintaining thyroid function while the contaminants can disturb thyroid morphology and homeostasis. In this study, we conducted metallomic analysis in thyroid cancer patients (n = 40) and control subjects (n = 40) recruited in Shenzhen, China with a high incidence of thyroid cancer. We found significant alterations in serumal and urinary metallomic profiling (including Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Cd, I, Ba, Tl, and Pb) and elemental correlative patterns between thyroid cancer patients and controls. Additionally, we also measured the serum Cu isotopic composition and found a multifaceted disturbance in Cu metabolism in thyroid disease patients. Based on the metallome variations, we built and assessed the thyroid cancer-predictive performance of seven machine learning algorithms. Among them, the Random Forest model performed the best with the accuracy of 1.000, 0.858, and 0.813 on the training, 5-fold cross-validation, and test set, respectively. The high performance of machine learning has demonstrated the great promise of metallomic analysis in the identification of thyroid cancer. Then, the Shapley Additive exPlanations approach was used to further interpret the variable contributions of the model and it showed that serum Pb contributed the most in the identification process. To the best of our knowledge, this is the first study that combines machine learning and metallome data for cancer identification, and it supports the indication of environmental heavy metal-related thyroid cancer etiology.

Initial characterization of an iron superoxide dismutase from Thermobifida fusca

Superoxide dismutases (SODs) are enzymes that catalyze the dismutation of the superoxide radical anion into O2 and H2O2 in a two-step reaction. They are ubiquitous to all forms of life and four different types of metal centers are detected, dividing this class of enzymes into Cu-/Zn-, Ni-, Mn-, and Fe-SODs. In this study, a superoxide dismutase from the thermophilic bacteria Thermobifida fusca (TfSOD) was cloned and expressed before the recombinant enzyme was characterized. The enzyme was found to be active for superoxide dismutation measured by inhibition of cytochrome c oxidation and the inhibition of the autoxidation of pyrogallol. Its pH-optimum was determined to be 7.5, while it has a broad temperature optimum ranging from 20 to 90 °C. Combined with the Tm that was found to be 78.5 ± 0.5 °C at pH 8.0, TfSOD can be defined as a thermostable enzyme. Moreover, the crystal structure of TfSOD was determined and refined to 1.25 Å resolution. With electron paramagnetic resonance spectroscopy, it was confirmed that iron is the metal co-factor of TfSOD. The cell potential (Em) for the TfSOD-Fe3+/TfSOD-Fe2+ redox couple was determined to be 287 mV.

A Redox Modulatory SOD Mimetic Nanozyme Prevents the Formation of Cytotoxic Peroxynitrite and Improves Nitric Oxide Bioavailability in Human Endothelial Cells

The endothelium-derived signalling molecule nitric oxide (NO) in addition to controlling multifarious servo-regulatory functions, suppresses key processes in vascular lesion formation and prevents atherogenesis and other vascular abnormalities. The conversion of NO into cytotoxic and powerful oxidant peroxynitrite (ONOO- ) in a superoxide (O2 .- )-rich environment has emerged as a major reason for reduced NO levels in vascular walls, leading to endothelial dysfunction and cardiovascular complications. So, designing superoxide dismutase (SOD) mimetics that can selectively catalyze the dismutation of O2 .- in the presence of NO, considering their rapid reaction is challenging and is of therapeutic relevance. Herein, the authors report that SOD mimetic cerium vanadate (CeVO4 ) nanozymes effectively regulate the bioavailability of both NO and O2 .- , the two vital constitutive molecules of vascular endothelium, even in the absence of cellular SOD enzyme. The nanozymes optimally modulate the O2 .- level in endothelial cells under oxidative stress conditions and improve endogenously generated NO levels by preventing the formation of ONOO- . Furthermore, nanoparticles exhibit size- and morphology-dependent uptake into the cells and internalize via the clathrin-mediated endocytosis pathway. Intravenous administration of CeVO4 nanoparticles in mice caused no definite organ toxicity and unaltered haematological and biochemical parameters, indicating their biosafety and potential use in biological applications.

Potential Use of Antioxidant Compounds for the Treatment of Inflammatory Bowel Disease

Since inflammatory bowel diseases (IBDs) are chronic, the development of new effective therapeutics to combat them does not lose relevance. Oxidative stress is one of the main pathological processes that determines the progression of IBD. In this regard, antioxidant therapy seems to be a promising approach. The role of oxidative stress in the development and progression of IBD is considered in detail in this review. The main cause of oxidative stress in IBD is an inadequate response of leukocytes to dysbiosis and food components in the intestine. Passage of immune cells through the intestinal barrier leads to increased ROS concentration and the pathological consequences of exposure to oxidative stress based on the development of inflammation and impaired intestinal permeability. To combat oxidative stress in IBD, several promising natural (curcumin, resveratrol, quercetin, and melatonin) and artificial antioxidants (N-acetylcysteine (NAC) and artificial superoxide dismutase (aSOD)) that had been shown to be effective in a number of clinical trials have been proposed. Their mechanisms of action on pathological events in IBD and clinical manifestations from their impact have been determined. The prospects for the use of other antioxidants that have not yet been tested in the treatment of IBD, but have the properties of potential therapeutic candidates, have been also considered.

Physiological response and molecular mechanisms against UV-B radiation in Brachionus asplanchnoidis (Rotifera)

Ultraviolet B (UV-B, 280-320 nm) radiation is a major environmental stressor for aquatic organisms on Earth's surface. Its effects on biological systems are well known, but the mechanisms by which organisms respond and adapt to UV-B radiation are still being explored. In this study, we investigated the effects of UV-B radiation on the monogonont rotifer Brachionus asplanchnoidis, focusing on physiological parameters, antioxidant systems, DNA damage, and DNA repair-related molecular mechanism. Our results showed that the LD50 was at 28.53 kJ/m2, indicating strong tolerance to UV-B. However, UV-B radiation caused adverse effects on growth and reproduction, with shortened reproductive period and longevity, decreased fecundity and hatchability, and inhibition of population growth. Biochemical analyses revealed severe oxidative damage and lipid peroxidation, with increased ROS and MDA levels. Activities of antioxidant enzymes were highly induced at low doses but decreased at high doses. DNA damage also occurred in UV-B-exposed rotifers. Furthermore, selected DNA repair-related genes were up-regulated in a dose-dependent manner. These findings provide a comprehensive understanding of the effects of UV-B radiation on rotifers and highlight the importance of considering both ecological and molecular responses in assessing the impact of UV-B radiation on aquatic organisms.

How Extracellular Reactive Oxygen Species Reach Their Intracellular Targets in Plants

Reactive oxygen species (ROS) serve as secondary messengers that regulate various developmental and signal transduction processes, with ROS primarily generated by NADPH OXIDASEs (referred to as RESPIRATORY BURST OXIDASE HOMOLOGs [RBOHs] in plants). However, the types and locations of ROS produced by RBOHs are different from those expected to mediate intracellular signaling. RBOHs produce O2•- rather than H2O2 which is relatively long-lived and able to diffuse through membranes, and this production occurs outside the cell instead of in the cytoplasm, where signaling cascades occur. A widely accepted model explaining this discrepancy proposes that RBOH-produced extracellular O2•- is converted to H2O2 by superoxide dismutase and then imported by aquaporins to reach its cytoplasmic targets. However, this model does not explain how the specificity of ROS targeting is ensured while minimizing unnecessary damage during the bulk translocation of extracellular ROS (eROS). An increasing number of studies have provided clues about eROS action mechanisms, revealing various mechanisms for eROS perception in the apoplast, crosstalk between eROS and reactive nitrogen species, and the contribution of intracellular organelles to cytoplasmic ROS bursts. In this review, we summarize these recent advances, highlight the mechanisms underlying eROS action, and provide an overview of the routes by which eROS-induced changes reach the intracellular space.

Genome-Wide Identification of Superoxide Dismutase and Expression in Response to Fruit Development and Biological Stress in Akebia trifoliata: A Bioinformatics Study

Akebia trifoliata is a newly domesticated perennial fruit tree, and the lack of molecular research on stress resistance seriously affects its genetic improvement and commercial value development. Superoxide dismutase (SOD) can effectively eliminate the accumulation of reactive oxygen species (ROS) during the rapid growth of plant organs under biotic and abiotic stresses, maintaining a steady state of physiological metabolism. In this study, 13 SODs consisting of two FeSODs (FSDs), four MnSODs (MSDs) and seven Cu/ZnSODs (CSDs) were identified in the A. trifoliata genome. Structurally, the phylogeny, intron–exon pattern and motif sequences within these three subfamilies show high conservation. Evolutionarily, segmental/wide genome duplication (WGD) and dispersed duplication form the current SOD profile of A. trifoliata. Weighted gene coexpression network analysis (WGCNA) revealed the metabolic pathways of nine (69.2%) SODs involved in fruit development, among which AktMSD4 regulates fruit development and AktCSD4 participates in the stress response. In addition, under the stress of multiple pathogens, six (46.6%) SODs were continuously upregulated in the rinds of resistant lines; of these, three SODs (AktMSD1, AktMSD2 and AktMSD3) were weakly or not expressed in susceptible lines. The results pave the way for theoretical research on SODs and afford the opportunity for genetic improvement of A. trifoliata.

Coenzyme Q10 and Fish Oil Supplementation for Reducing Retinal Oxidative Stress in a Rat Model

Extremely low gestational-age neonates requiring supplemental oxygen experience intermittent hypoxia (IH) episodes, which predispose them to oxidative stress and retinopathy of prematurity. We tested the hypothesis that early supplementation with fish oil or CoQ10 confers benefits reducing the severity of IH-induced retinopathy. At birth, rat pups were exposed to two clinically relevant neonatal IH paradigms with recovery in either hyperoxia (50% O2) or room air (RA) between episodes for 14 days, during which they received daily oral fish oil, coenzyme Q10 (CoQ10) in olive oil (OO), or OO only (vehicle). At postnatal day 14 (P14), pups were allowed to recover in RA with no further treatment until P21. Retinas were examined at P14 and at P21. Both IH paradigms resulted in severe ocular oxidative stress and retinopathy regardless of recovery in hyperoxia or RA in the vehicle groups. Although early supplementation with fish oil was beneficial, CoQ10 provided superior benefits for reducing IH-induced oxidative stress and retinopathy. These effects were associated with lower retinal antioxidants and biomarkers of angiogenesis. The therapeutic benefits of CoQ10 suggest a potential treatment for IH-induced retinopathies. Further studies are needed to establish appropriate, safe, and effective doses for use in preterm infants.

Identifying Bioactive Ingredients and Antioxidant Activities of Wild Sanghuangporus Species of Medicinal Fungi

Sanghuangporus refers to a group of rare medicinal fungi with remarkable therapeutic properties. However, current knowledge on the bioactive ingredients and antioxidant activities of different species of this genus is limited. In this study, a total of 15 wild strains from 8 species of Sanghuangporus were selected as the experimental materials for identification of the bioactive components (polysaccharide, polyphenol, flavonoid, triterpenoid, and ascorbic acid) and antioxidant activities (scavenging activities against hydroxyl, superoxide, DPPH, and ABTS radicals; superoxide dismutase activity; and ferric reducing ability of plasma). Notably, individual strains contained different levels of various indicators, among which Sanghuangporus baumii Cui 3573, S. sanghuang Cui 14419 and Cui 14441, S. vaninii Dai 9061, and S. zonatus Dai 10841 displayed the strongest activities. The correlation analysis of bioactive ingredients and antioxidant activities revealed that the antioxidant capacity of Sanghuangporus is mainly associated with the contents of flavonoid and ascorbic acid, followed by polyphenol and triterpenoid, and finally, polysaccharide. Together, the results obtained from the comprehensive and systematic comparative analyses contribute further potential resources and critical guidance for the separation, purification, and further development and utilization of bioactive agents from wild Sanghuangporus species, as well as the optimization of their artificial cultivation conditions.