Influence Of Reactive Oxygen Species Research Articles

NOX2 Enzyme Mimicking Nano-Networks Regulate Tumor-Associated Macrophages to Initiate Both Innate and Adaptive Immune Effects.

Macrophages, capable of both direct killing and antigen presentation, are crucial for the interplay between innate and adaptive immunity. However, strategies mainly focus on polarizing tumor-associated macrophages (TAMs) to M1 phenotype, while overlooking the inefficient antigen cross-presentation due to hyperactive hydrolytic protease within lysosomes which leads to antigen degradation. In light of the significant influence of reactive oxygen species (ROS) on TAMs' polarization and the inhibition of phagosomal proteolysis, a novel nanosystem termed OVA-Fe-GA (OFG) is engineered, drawing inspiration from the NOX2 enzyme's role. OFG integrates ovalbumin (OVA) and a network composed of Fe-gallic acid (GA), emulating the NOX2 enzyme's sequential ROS generation process ("O2 to O2 •- to H2O2/•OH"). Furthermore, it elucidates a biological mechanism that augments antigen cross-presentation by suppressing the expression of cysteine proteases. OFG restores the innate anti-tumor functionality of TAMs and significantly amplifies their antigen cross-presentation (4.5-fold compared to the PBS control group) in B16-OVA tumor-bearing mice. Notably, the infiltration and activity of intratumoral CD8+ T cells are enhanced, indicating an adaptive immune response. Moreover, OFG exhibits excellent photothermal properties, thereby fostering a system antitumor immune response. This study provides a promising strategy for initiating both innate and adaptive immunity via TAMs activation.

An investigation of the influence of reactive oxygen species produced from riboflavin-5′-phosphate by blue or violet light on the inhibition of WiDr colon cancer cells

Riboflavin-5′-phosphate (FMN), an innocuous product of riboflavin (RF) phosphorylation, is vital for humans. FMN is sensitive to light illumination, as indicated by reactive oxygen species (ROS) formation. This investigation was undertaken to evaluate the influence of blue light illumination (BLI) and violet light illumination (VLI) upon FMN to develop a method to inhibit WiDr colon cancer cells by FMN photolysis. When FMN is subjected to BLI and VLI, it inhibits WiDr colon cancer cells by generating superoxide radical anions (O2•−). The respective reduction rates are 42.6 and 81.9 % in WiDr colon cancer cells for FMN treated with BLI and VLI at 20 W/m2 for 0.5 h. FMN treated with VLI inhibits WiDr colon cancer cells more effectively than BLI. Propidium iodide (PI) is a fluorescent dye that is used to detect abnormal DNA due to cell death by apoptosis or necrosis. The PI-positive count for nuclei increased significantly for the WiDr colon cancer cells that were treated with FMN under VLI at 20 W/m2 for 0.5 h. FMN photolysis achieved using VLI allows efficient photodynamic therapy (PDT) by triggering the cytotoxicity of FMN on WiDr colon cancer cells.

Influence of Reactive Oxygen Species on Wound Healing and Tissue Regeneration in Periodontal and Peri-Implant Tissues in Diabetic Patients.

Diabetes mellitus (DM) is associated with periodontal disease. Clinically, periodontal treatment is less effective for patients with DM. Oxidative stress is one of the mechanisms that link DM to periodontitis. The production of reactive oxygen species (ROS) is increased in the periodontal tissues of patients with DM and is involved in the development of insulin resistance in periodontal tissues. Insulin resistance decreases Akt activation and inhibits cell proliferation and angiogenesis. This results in the deterioration of wound healing and tissue repair in periodontal tissues. Antioxidants and insulin resistance ameliorants may inhibit ROS production and improve wound healing, which is worsened by DM. This manuscript provides a comprehensive review of the most recent basic and clinical evidence regarding the generation of ROS in periodontal tissues resulting from microbial challenge and DM. This study also delves into the impact of oxidative stress on wound healing in the context of periodontal and dental implant therapies. Furthermore, it discusses the potential benefits of administering antioxidants and anti-insulin resistance medications, which have been shown to counteract ROS production and inflammation. This approach may potentially enhance wound healing, especially in cases exacerbated by hyperglycemic conditions.

Види клітинної загибелі, що реалізуються через вплив активних форм кисню і пошкодження ДНК

The purpose of the review was to find and analyze the literature on such types of cell death, which are realized due to DNA damage, namely, mitotic catastrophe; anoikis; pyroptosis; parthanatos and due to the influence of active forms of oxygen, namely mitoptosis; lysosome-dependent cell death; necrosis associated with increased mitochondrial permeability; necroptosis; netosis; ferroptosis. Apoptosis and autophagy, which are realized both due to the influence of reactive oxygen species and DNA damage, are considered separately.Cell death plays an important role in development, tissue homeostasis, inflammation, immunity, and many pathophysiological conditions. On the one hand, it becomes an etiological determinant in diseases associated with the irreversible loss of postmitotic tissues (for example, myocardial infarction, neurodegeneration). On the other hand, defects in the signaling cascades that trigger cell death are associated with pathologies characterized by uncontrolled expansion or accumulation of cells (eg, some autoimmune diseases, cancer). Therefore, cell death can be defined as a promising therapeutic target.

An overlooked influence of reactive oxygen species on ammonia-oxidizing microbial communities in redox-fluctuating aquifers

Reactive oxygen species (ROS) are ubiquitous in O2-perturbed aquifers, but their role in shaping ammonia-oxidizing microbial communities is not clear. This study examined the dynamic responses of ammonia-oxidizing microorganisms (AOMs) in redox-fluctuating aquifers to ROS via field investigation and in-lab verification using transcriptomes/ metatranscriptome and RT-qPCR. Ammonia-oxidizing archaea (AOA) dominated recharge aquifers with lower ROS levels, whereas ammonia-oxidizing bacteria (AOB) and heterotrophic nitrifying aerobic bacteria (HNB) predominated in discharge areas with higher ROS levels. Similar succession in AOM enrichments was found in that the dominant AOMs changed from AOA Nitrosopumilus to AOB Nitrosomonas with increasing ROS. Ammonia oxidation and antioxidant capacity differed significantly among three AOM isolates exposed to ROS. ROS decreased the amoA gene expression of AOA strain Nitrososphaera viennensis PLX03, accompanied by inhibited ammonia oxidation capacity. By contrast, the catalase and superoxide dismutase activities of the AOB strain Nitrosomonas oligotropha PLL12 and HNB strain Pseudomonas aeruginosa PLL01 increased, and the antioxidant genes katG, sodA, ahpC, and ahpF were significantly upregulated. These results demonstrate that ROS exert an important influence on AOMs in redox-fluctuating aquifers. This study improves our understanding of the ecological niches of AOMs in surface/subsurface environments.

Influence of reactive oxygen species responsive self-assembled nanomicelle loaded with pyroptosis inhibitor on full-thickness skin defects in diabetic rats

Objective: To investigate the influence of reactive oxygen species (ROS) responsive self-assembled nanomicelle loaded with pyroptosis inhibitor on full-thickness skin defects in diabetic rats. Methods: Experimental research methods were employed. A nucleotide-binding oligomerization domain (NOD) 1/2 inhibitor (NOD-IN-1) was encapsulated with nanomicelle polyethylene glycol-block-polypropylene sulfide (PEG-b-PPS), and the resulting product was called PEPS@NOD-IN-1. The morphology and hydration particle size of PEG-b-PPS and PEPS@NOD-IN-1 were observed by transmission electron microscope and particle size analyzer, respectively, and the encapsulation rate and drug loading rate of PEPS@NOD-IN-1 to NOD-IN-1 and the cumulative release rate of NOD-IN-1 by PEPS@NOD-IN-1 in phosphate buffer solution (PBS) alone and hydrogen peroxide-containing PBS within 40 h were measured and calculated by microplate reader, and the sample number was 3. Twenty-four male Sprague-Dawley rats aged 6-7 weeks were injected with streptozotocin to induce type 1 diabetes mellitus. Six full-thickness skin defect wounds were made on the back of each rat. The injured rats were divided into PBS group, NOD-IN-1 group, PEG-b-PPS group, and PEPS@NOD-IN-1 group with corresponding treatment according to the random number table, with 6 rats in each group. The wound healing was observed on post injury day (PID) 3, 7, and 12, and the wound healing rate was calculated. The ROS levels in wound tissue were detected by immunofluorescence method on PID 3. On PID 7, the granulation tissue thickness in wound was assessed by hematoxylin-eosin staining, the mRNA expressions of NOD1 and NOD2 were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction, and the protein expressions of NOD1, NOD2, and GSDMD-N terminals were detected by Western blotting. Six wounds from different rats in each group were taken for detection of the above indicators. Wound tissue (3 samples per group) was taken from rats in PBS group and PEPS@NOD-IN-1 group on PID 7, and transcriptome sequencing was performed using high-throughput sequencing technology platform. Differentially expressed genes (DEGs) significantly down-regulated in PEPS@NOD-IN-1 group as compared with PBS group were screened, and the enrichment analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) was performed. The DEG heatmap of the NOD-like receptor pathway, a pyroptosis-related pathway, was made. Protein-protein interaction (PPI) analysis of DEGs in heatmap was performed through the STRING database to screen key genes of PEPS@NOD-IN-1 regulating the NOD-like receptor pathway. Data were statistically analyzed with analysis of variance for repeated measurement, one-way analysis of variance, and Tukey test. Results: PEG-b-PPS and PEPS@NOD-IN-1 were in spherical structures of uniform size, with hydration particle sizes of (134.2±3.3) and (143.1±2.3) nm, respectively. The encapsulation rate of PEPS@NOD-IN-1 to NOD-IN-1 was (60±5)%, and the drug loading rate was (15±3)%. The release of NOD-IN-1 from PEPS@NOD-IN-1 in PBS alone was slow, and the cumulative release rate at 40 h was only (12.4±2.3)%. The release of NOD-IN-1 from PEPS@NOD-IN-1 in hydrogen peroxide-containing PBS within 10 h was very rapid, and the cumulative release rate at 10 h reached (90.1±3.6)%. On PID 3 and 7, the wounds of rats in the four groups were gradually healed, and the healing in PEPS@NOD-IN-1 group was better than that in the other three groups. On PID 12, the wound scab area in PBS group was large, the wound epithelialization in NOD-IN-1 group and PEG-b-PPS group was obvious, and the wound in PEPS@NOD-IN-1 group was close to complete epithelialization. Compared with those in PBS group, NOD-IN-1 group, and PEG-b-PPS group, the wound healing rates on PID 7 and 12 in PEPS@NOD-IN-1 group were significantly increased (P<0.05), the level of ROS in wound tissue on PID 3 was significantly decreased (P<0.05), the thickness of granulation tissue in wound on PID 7 was significantly thickened (P<0.05), and the mRNA expressions of NOD1 and NOD2 and the protein expressions of NOD1, NOD2, and GSDMD-N terminals in wound tissue on PID 7 were significantly decreased (P<0.05). KEGG pathway analysis showed that DEGs significantly down-regulated in PEPS@NOD-IN-1 group as compared with PBS group were significantly enriched in NOD-like receptors, hypoxia-inducible factors, mitogen-activated protein kinases, and tumor necrosis factor (TNF) pathways. In the DEG heatmap of NOD-like receptor pathway, the genes regulating pyroptosis mainly involved NOD1, NOD2, NOD-like receptor thermoprotein domain-related protein 3, Jun, signal transduction and transcriptional activator 1 (STAT1), TNF-α-induced protein 3. The PPI results showed that NOD1, NOD2, and STAT1 were the key genes of PEPS@NOD-IN-1 regulating the NOD-like receptor pathway. Conclusions: PEPS@NOD-IN-1 can down-regulate the level of local ROS in wounds and the expression of NOD1, NOD2, and GSDMD-N terminals, the key regulators of pyroptosis, thereby promoting the repair of full-thickness skin defect wounds in diabetic rats. PEPS@NOD-IN-1 can also significantly down-regulate the pyroptosis, inflammation, and hypoxia-related pathways of wounds, and regulate NOD-like receptor pathways by down-regulating key genes NOD1, NOD2, and STAT1.

Toxicity of boron nitride nanoparticles influencing bio-physicochemical responses in freshwater green algae.

Boron nanoparticles have emerged as promising nanomaterials with a wide array of applications in the biomedical, industrial, and environmental fields. However, the potential impact of these nanoparticles on aquatic organisms is not yet known. In the present study, the comparative impact of boron nitride nanoparticles and its bulk form is investigated on two freshwater algae. For this purpose, the effect on the physiological index, cellular morphology, and biochemistry profiles are examined. In Chlorella vulgaris, nano form of boron nitride is found to reduce the growth more (40%) than its bulk form (with ~ 25% growth reduction) at 50 mgl-1 treatment level. While in case of Coelastrella terrestris, 40% reduction under nano form and 33.33% reduction under bulk form is observed at 100 mgl-1 of boron nitride. Chlorophyll and carotenoid levels were also reduced under nanoparticles compared to the bulk. Proline, lactate dehydrogenase, and malondialdehyde assay were found significantly high under nanoparticle exposure. Additionally, increased catalase and superoxide dismutase enzyme activity under nanoparticle exposure revealed that the antioxidant system was activated in both the algae to eliminate the adverse influence of reactive oxygen species. The shading effect and aggregation of nanoparticles over the surface of algal cells are also important factors in attributing toxicity which are confirmed through the compound, TEM, and SEM micrographs. The study suggests that the nano form is more toxic than the bulk form and toxicity is concentration-dependent.

Allelopathic Toxicity of Cyanamide Could Control Amaranth (Amaranthus retroflexus L.) in Alfalfa (Medicago sativa L.) Field.

The inclination toward natural products has led to the onset of the discovery of new bioactive metabolites that could be targeted for specific therapeutic or agronomic applications. Despite increasing knowledge coming to light of allelochemicals as leads for new herbicides, relatively little is known about the mode of action of allelochemical-based herbicides on herbicide-resistant weeds. Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). This study aimed to detect the toxicity of cyanamide to alfalfa and amaranth. Seed germination experiments were carried out by the filter paper culture, and the seedling growth inhibition experiment was carried out by spraying alfalfa (Medicago sativa L.) and amaranth (Amaranthus retroflexus L.) seedlings with cyanamide. The results showed that when the concentration of cyanamide was 0.1 g·L-1, the germination of amaranth seeds could be completely inhibited without affecting the germination of alfalfa seeds. At the concentration of 0.5 g·L-1, cyanamide could significantly inhibit the growth of the root and stem of amaranth seedlings but did not affect the growth of alfalfa. This effect was associated with the induction of oxidative stress. The ascorbate peroxidase (APX) and catalase (CAT) activity of amaranth decreased by 6.828 U/g FW and 290.784 U/g FW, respectively. The malondialdehyde (MDA) content, peroxidase (POD), and superoxide dismutase (SOD) activity of amaranth firstly increased and then decreased with the increasing concentration of CA. These enzyme activities of amaranth changed more than that of alfalfa. Activities of the antioxidant enzymes APX, CAT, POD, and SOD and the content of MDA varied dramatically, thereby demonstrating the great influence of reactive oxygen species upon identified allelochemical exposure. In addition, cyanamide can also inhibit the production of chlorophyll, thereby affecting the growth of plants. From the above experiments, we know that cyanamide can inhibit the growth of amaranth in alfalfa fields. Thus, the changes caused by cyanamide described herein can contribute to a better understanding of the actions of allelochemical and the potential use of cyanamide in the production of bioherbicides.

Crosstalk between AML and stromal cells triggers acetate secretion through the metabolic rewiring of stromal cells.

Acute myeloid leukaemia (AML) cells interact and modulate components of their surrounding microenvironment into their own benefit. Stromal cells have been shown to support AML survival and progression through various mechanisms. Nonetheless, whether AML cells could establish beneficial metabolic interactions with stromal cells is underexplored. By using a combination of human AML cell lines and AML patient samples together with mouse stromal cells and a MLL-AF9 mouse model, here we identify a novel metabolic crosstalk between AML and stromal cells where AML cells prompt stromal cells to secrete acetate for their own consumption to feed the tricarboxylic acid cycle (TCA) and lipid biosynthesis. By performing transcriptome analysis and tracer-based metabolic NMR analysis, we observe that stromal cells present a higher rate of glycolysis when co-cultured with AML cells. We also find that acetate in stromal cells is derived from pyruvate via chemical conversion under the influence of reactive oxygen species (ROS) following ROS transfer from AML to stromal cells via gap junctions. Overall, we present a unique metabolic communication between AML and stromal cells and propose two different molecular targets, ACSS2 and gap junctions, that could potentially be exploited for adjuvant therapy.

Reactive Oxygen Species Contributes to Type 2 Diabetic Neuropathic Pain via the Thioredoxin-Interacting Protein-NOD-Like Receptor Protein 3- N -Methyl-D-Aspartic Acid Receptor 2B Pathway.

BACKGROUND:The number of patients with diabetic neuropathic pain (DNP) continues to increase, but available treatments are limited. This study aimed to examine the influence of reactive oxygen species (ROS)-thioredoxin-interacting protein (TXNIP)-NOD–like receptor protein 3 (NLRP3)-N-methyl-D-aspartic acid receptor 2B (NR2B) pathway on type 2 DNP.METHODS:Male Sprague-Dawley rats were fed with a high-fat and high-sugar diet for 8 weeks. Then, rats were intraperitoneally injected with streptozotocin (STZ, 35 mg/kg) to induce type 2 diabetes mellitus in rats. Diabetic rats with <85% of their basic levels in mechanical withdrawal threshold and thermal withdrawal latency were classified as DNP rats on day 14 after STZ injection. DNP rats were treated with ROS scavenger N-tert-Butyl-α-phenylnitrone (PBN, 100 mg·kg–1·d–1) or TXNIP small interfering ribonucleic acid (10 μg/d) once daily for 14 days. The level of ROS, protein levels of NLRP3, TXNIP, cysteinyl aspartate-specific proteinase-1 (caspase-1), interleukin-1β (IL-1β), NR2B phosphorylation at Tyr1472 (p-NR2B), total NR2B (t-NR2B), and distribution of NLRP3 in the spinal cord were examined. In vitro experiments, BV2 cells and PC12 cells were individually cultured and cocultured in a high-glucose environment (35 mmol/L D-glucose). The level of ROS and protein levels of NLRP3, TXNIP, caspase-1, and IL-1β in BV2 cells, and p-NR2B, t-NR2B in PC12 cells were detected. The level of ROS was detected by the flow cytometry approach. The protein levels were detected by the Western blot technique. The location of NLRP3 was observed by immunofluorescent staining. The interaction between TXNIP and NLRP3 was detected by coimmunoprecipitation assay.RESULTS:The level of spinal ROS increased in DNP rats. The mechanical allodynia and thermal hyperalgesia of DNP rats were alleviated after systemic administration of PBN. This administration decreased protein levels of NLRP3, TXNIP, caspase-1, IL-1β, and p-NR2B and the coupling of TXNIP to NLRP3 in spinal cords of DNP rats. Furthermore, knockdown of spinal TXNIP alleviated nociceptive hypersensitivity and decreased protein levels of NLRP3, TXNIP, caspase-1, IL-1β, and p-NR2B in DNP rats. The level of ROS and protein levels of NLRP3, TXNIP, caspase-1, IL-1β, the coupling of TXNIP to NLRP3, and the IL-1β secretion increased in BV2 cells, and the protein expression of p-NR2B increased in cocultured PC12 cells in a high-glucose environment. All of these in vitro effects were significantly blocked after treatment of PBN.CONCLUSIONS:Our findings suggest that spinal ROS can contribute to type 2 DNP through TXNIP-NLRP3-NR2B pathway.

The influence of reactive oxygen species on “respiration” isotope effects

The triple-oxygen isotope (17O/16O, 18O/16O) measurement of oxygen-bearing species represents one of the most robust tools to directly trace oxygen cycling in the environment. One particularly consequential application of this isotope system is the analysis of dissolved oxygen (O2) in aquatic environments to determine gross oxygen production. This approach assumes that photosynthesis, microbial respiration, and gas exchange are the main drivers of dissolved O2 isotope compositions, and that each process is described by predictable, consistent triple-oxygen isotope effects. However, there currently exists large disagreement in the literature on the triple-oxygen isotope effect of respiration, which carries major implications for global primary productivity estimates. Recent work has additionally highlighted the ubiquitous production of extracellular reactive oxygen species (ROS) such as superoxide (O2.-) and hydrogen peroxide (H2O2) by microorganisms; this flux may be responsible for as much as 20% of net oxygen utilization in the ocean. To examine the influence of ROS-mediated O2 recycling on the oxygen utilization isotope effect, we measured the triple-oxygen isotope fractionations and mass laws of superoxide dismutase, catalase, and iron-mediated H2O2 degradation. We incorporate these constraints into an oxygen isotope flux model to explore the influence of ROS-mediated oxygen cycling on “respiration” isotope effects in previous studies. We find that ROS-mediated oxygen cycling can reconcile the previously reported range of triple-oxygen isotope fractionation factors and that typical marine isotope effects are broadly consistent with independent estimates of superoxide-mediated oxygen loss. Lastly, we determine that O2.- production likely follows non-canonical triple-oxygen isotope mass laws (⩽0.510), indicating that this process may exert significant leverage on dissolved O2 isotope compositions and thus primary productivity estimates. We conclude that ROS cycling should be considered when using dissolved O2 triple-oxygen isotopes to determine marine primary productivity.

Mitochondrial Superoxide is the Key for Promoting Cell Migration in Wound Healing

Introduction: The focus of current study was to investigate the role of mitochondrial superoxide for promoting cell migration in healing responses. Methods: To simulate the skin wound healing process, scratch wound assay in A549 cells was utilized. Subsequently, mitochondrial superoxide and intracellular calcium flux (Ca2+) were measured by MitoSox red reagent and Fluo-4 staining. Paraquat (PQ), N-acetyl cysteine (NAC), superoxide dismutase (SOD) mimics (EUK-134), free radical scavenge (MCI-186), and diphenyliodonium (DPI) were added into medium to evaluate the influences of reactive oxygen species (ROS) and superoxide on cell migration. Results: Compared with before wound (BW), mitochondrial superoxide increased time-dependent manner. Correspondingly, Ca2+ transients was rapidly elevated after scratch wound and gradually declined toward an steady level, as evidenced by Fluo-4 fluorescence intensity. Scratch wound assay displayed that cell migration in PQ 0.1 mM group was stronger than that of Control group, whilst it was restrained after administration of 10 mM NAC. Additionally, cell migration in EUK-134 and MCI-186 group was conspicuously lower than that of Control group and similar with the degree of inhibiting role of DPI, indicating that mitochondrial superoxide served the crux influence on promoting cell migration after scratch. Conclusion: ROS and superoxide production during scratch wound facilitated cell migration. Importantly, mitochondrial superoxide played the positive effects on healing response.

Influence of reactive oxygen species concentration and ambient temperature on the evolution of chemical bonds during plasma cleaning: a molecular dynamics simulation.

The research on plasma chemistry involved in the formation and dissociation of abundant chemical bonds is fundamental to developing plasma cleaning. To understand the influence of reactive oxygen species' concentration and ambient temperature on the evolution behavior of the chemical bond during plasma cleaning, microscopic reaction models between organic contaminants and reactive oxygen species were established and performed by reactive molecular dynamics. Dibutyl phthalate, as a representative organic contaminant, was selected as the research object. The simulation results suggested that hydrogen bonds between hydroxyl radicals reduced the mobility of reactive species, resulting in the cleaning ability of hydroxyl radicals being much lower than atomic oxygen and ozone radicals. The concentration of reactive species dominated the efficiency of plasma cleaning, and the increase in ambient temperature further improved the cleaning ability. C-H, C-C and C-O bonds were gradually oxidized to C[double bond, length as m-dash]C, C-O, C[double bond, length as m-dash]O and O-H bonds by hydrogen abstraction reaction during the reaction of reactive species with organic contaminants. An increase in ambient temperature induced the possibility of benzene ring destruction under the action of reactive species, which was considered a method of complete dissociation of aromatic hydrocarbons.

Polycyclic aromatic hydrocarbon exposure, oxidative potential in dust, and their relationships to oxidative stress in human body: A case study in the indoor environment of Guangzhou, South China

A comparative study of internal and external exposure is a good method to comprehensively understand human exposure to environmental contaminants that may trigger oxidative stress in human body. Information is limited regarding the influences of reactive oxygen species (ROS) on human health from the environment. In addition, data on the contribution of polycyclic aromatic hydrocarbons (PAHs) from indoor environments, especially air, to total human exposure are still insufficient. The present study measured PAHs in paired indoor dust (n = 101), gas (polyurethane foams, n = 100), and particle samples (quartz fiber filters, n = 100) and their hydroxy metabolites (OH-PAHs) in 205 urine samples from 101 families in Guangzhou, South China. The oxidative potential (OP) in dust samples was quantified with a dithiothreitol (DTT) assay to reflect the oxidizability of ROSs, and explore the relationship between environmental ROSs and oxidative stress in humans (using urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) as a biomarker). The estimated daily intakes (EDIs) of Σ16PAH via air inhalation were much higher than those from gas dermal contact, dust dermal contact, and dust ingestion (mean: 19.5 > 4.27 > 3.75 > 1.60 ng/kg_bw/day). Generally, approximately 16% of naphthalene, 28% of fluorene, 9% of phenanthrene, and 3% of pyrene were derived from indoor environments for all residents when compared with the total PAH exposure amount from all sources. Significantly positive relationships were found between OH-PAHs and 8-OHdG (coefficients β: 0.129–0.366, p < 0.05) checked by linear mixed effect models, and males seemed to be more susceptible than females to the DNA oxidative damage related to PAH exposure. The mean OP value in dust was 7.14 ± 6.68 pmol/(min·μg). Individual PAHs in dust gradually intensified the oxidizability of dust particles as their molecular weight increased. A potential but not significant dose-relationship was found between dusty OP and urinary 8-OHdG. Further work should determine the impact of chemical profiles on OP in different environmental media and continuously explore the potential to use OP as a useful indicator to reflect the total oxidizability of several groups of environmental pollutants.

Physiological and molecular responses in halotolerant Dunaliella salina exposed to molybdenum disulfide nanoparticles

Molybdenum disulfide nanoparticles (MoS2 NPs) has emerged as the promising nanomaterial with a wide array of applications in the biomedical, industrial and environmental field. However, the potential effect of MoS2 NPs on marine organisms has yet to be reported. In this study, the effect of MoS2 NPs on the physiological index, subcellular morphology, transcriptomic profiles of the marine microalgae Dunaliella salina was investigated for the first time. exhibited “doping-like” effects on marine microalgae; Growth stimulation was 193.55%, and chlorophyll content increased 1.61-fold upon the addition of 50 μg/L MoS2 NPs. Additionally, exposure to MoS2 NPs significantly increased the protein and carbohydrate content by 2.03- and 1.56-fold, respectively. The antioxidant system was activated as well to eliminate the adverse influence of reactive oxygen species (ROS). Transcriptomic analysis revealed that genes involved in porphyrin synthesis, glycolysis/gluconeogenesis, tricarboxylic acid cycle and DNA replication were upregulated upon MoS2 NPs exposure, which supports the mechanistic role of MoS2 NPs in improving cellular growth and photosynthesis. The “doping-like” effects on marine algae suggest that the low concentration of MoS2 NPs might change the rudimentary ecological composition in the ocean.

The influence of reactive oxygen species and NO on oxidative metabolism and dielectric properties of living tissue

The influence of reactive oxygen species and NO on oxidative metabolism and dielectric properties of living tissue

The Influence of Reactive Oxygen Species in the Immune System and Pathogenesis of Multiple Sclerosis.

Multiple roles have been indicated for reactive oxygen species (ROS) in the immune system in recent years. ROS have been extensively studied due to their ability to damage DNA and other subcellular structures. Noticeably, they have been identified as a pivotal second messenger for T-cell receptor signaling and T-cell activation and participate in antigen cross-presentation and chemotaxis. As an agent with direct toxic effects on cells, ROS lead to the initiation of the autoimmune response. Moreover, ROS levels are regulated by antioxidant systems, which include enzymatic and nonenzymatic antioxidants. Enzymatic antioxidants include superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase. Nonenzymatic antioxidants contain vitamins C, A, and E, glutathione, and thioredoxin. Particularly, cellular antioxidant systems have important functions in maintaining the redox system homeostasis. This review will discuss the significant roles of ROS generation and antioxidant systems under normal conditions, in the immune system, and pathogenesis of multiple sclerosis.

An ultrasensitive chemiluminescence assay for 4-nitrophenol by using luminol-NaIO4 reaction catalyzed by copper, nitrogen co-doped carbon dots.

A chemiluminescence (CL) assay on the basis of the tremendous enhancing effect of copper and nitrogen co-doped carbon dots (Cu,N-CDs) on the luminol-NaIO4 reaction was introduced for the determination of nanomolar levels of 4-nitrophenol (4-NP). Cu,N-CDs were synthesized by a hydrothermal approach and characterized by TEM, XRD, EDX, and FTIR analysis. The potential CL mechanism was elucidated by recording the CL spectrum and by evaluating the influence of reactive oxygen species. It was found that 4-NP remarkably inhibited the luminol-NaIO4-Cu,N-CDs reaction and reduced the CL signal of the reaction. This fact was applied for developing a CL assay for 4-NP. Under the optimized conditions, 4-NP could be determined in the concentration range of 0.25 to 150nM, with a detection limit as low as 0.06nM. This assay was successfully exploited for the analysis of 4-NP in real environmental samples.

2019 Academy Proceedings

2019 Academy Proceedings

Reactive oxygen species altering the metabolite profile of the marine-derived fungus Dichotomomyces cejpii F31-1

To investigate the influence of reactive oxygen species (ROS) on the secondary metabolites of the marine-derived fungus Dichotomomyces cejpii F31-1, hydrogen peroxide (H2O2) was added to the GPY culture medium. The HPLC chromatogram of the EtOAc extract of the culture broth was distinct from that of the H2O2 free GPY medium. Further study of the metabolites in the GPY medium with H2O2 resulted in the discovery of eight known compounds. Among them, (22E)-5α, 8α-epidioxyergosta-6, 22-dien-3β-ol (2) and ergosta-4,6,8(14),22-tetraene-3-one (3) were present in the highest concentration, while ergosterol and diketopiperazines are abundant in the H2O2 free medium. Additionally, a new compound, dichocetide D (1) containing a chlorine element and a known ergosterol (10) were isolated from the H2O2 free medium. (22E)-5α, 8α-epidioxyergosta-6, 22-dien-3β-ol (2) exhibited moderate cytotoxic activity against human prostate cancer cell line LNCaP-C4-2B.