Reactive Oxygen Species Content Research Articles

Transcriptome analysis of antioxidant system response in Styrax tonkinensis seedlings under flood-drought abrupt alternation.

Styrax tonkinensis (Pierre) Craib ex Hartwich faces challenges in expanding in the south provinces of Yangtze River region due to climate extremes like flood-drought abrupt alternation (FDAA) caused by global warming. Low tolerance to waterlogging and drought restricts its growth in this area. To study its antioxidant system and molecular response related to the peroxisome pathway under FDAA, we conducted experiments on two-year-old seedlings, measuring growth indexes, reactive oxygen species content, antioxidant enzyme activity, and analyzing transcriptomes under FDAA and drought (DT) conditions. The physiological results indicated a reduction in water content in roots, stems, and leaves under FDAA conditions. The most significant water loss, amounting to 15.53% was observed in the leaves. Also, ROS accumulation was predominantly observed in leaves rather than roots. Through transcriptome analysis, we assembled a total of 1,111,088 unigenes (with a total length of 1,111,628,179bp). Generally, SOD1 and CAT genes in S. tonkinensis seedlings were up-regulated to scavenge ROS. Conversely, the MPV17 gene exhibited contrasting reaction with up-regulation in leaves and down-regulation in roots, leading to increased ROS accumulation in leaves. CHS and F3H were down-regulated, which did not play an essential role in scavenging ROS. Moreover, the down-regulation of PYL, CPK and CALM genes in leaves may not contribute to stomatal closure, thereby causing continuous water loss through transpiration. Whereas, the decreased root vigor during the waterlogging phase and up-regulated CPK and CALM in roots posed obstacles to water absorption by roots. Additionally, the DEGs related to energy metabolism, including LHCA and LHCB, were negatively regulated. The ROS generation triggered by MPV17 genes was not the main reason for the eventual mortality of the plant. Instead, plant mortality may be attributed to water loss during the waterlogging phase, decreased root water uptake capacity, and continued water loss during the subsequent drought period. This study establishes a scientific foundation for comprehending the morphological, physiological, and molecular facts of S. tonkinensis under FDAA conditions.

A multilevel investigation to reveal the regulatory mechanism of lignin accumulation in juice sac granulation of pomelo

Granulation of juice sacs is a physiological disorder, which affects pomelo fruit quality. Here, the transcriptome and ubiquitinome of the granulated juice sacs were analyzed in Guanxi pomelo. We found that lignin accumulation in the granulated juice sacs was regulated at transcription and protein modification levels. In transcriptome data, we found that the genes in lignin biosynthesis pathway and antioxidant enzyme system of the granulated juice sacs were significantly upregulated. However, in ubiquitinome data, we found that ubiquitinated antioxidant enzymes increased in abundance but the enzyme activities decreased after the modification, which gave rise to reactive oxygen species (ROS) contents in granulated juice sacs. This finding suggests that ubiquitination level of the antioxidant enzymes is negatively correlated with the enzyme activities. Increased H2O2 is considered to be a signaling molecule to activate the key gene expressions in lignin biosynthesis pathway, which leads to the lignification in granulated juice sacs of pomelo. This regulatory mechanism in juice sac granulation of pomelo was further confirmed through the verification experiment using tissue culture by adding H2O2 or dimethylthiourea (DMTU). Our findings suggest that scavenging H2O2 and other ROS are important for reducing lignin accumulation, alleviating juice sac granulation and improving pomelo fruit quality.

Mitigating Effect of Exogenous Melatonin on Salt and Drought Stress in Cyperus esculentus L. during the Tillering Stage

Drought and salt stress are important limiting factors that affect crop growth and yield. As a newly recognized plant hormone, melatonin can participate in the regulation of plant stress tolerance and enhance the tolerance of plants to adversity. In this study, the effects of melatonin (150 µmol·L−1) on agronomic traits, osmotic adjustment substances, antioxidant enzyme activities, and reactive oxygen species content in C. esculentus under different salt (0 and 200 mmol·L−1 NaCl), drought (70% field capacity, 50% field capacity), and salt–drought (200 mmol·L−1 NaCl + 50% field capacity) stress conditions were determined using a pot experiment. Spraying with 150 µmol·L−1 of melatonin effectively improved the plant height, number of blades, biomass, and root growth of C. esculentus seedlings under salt, drought, and combined stress. In addition, this treatment also increased the relative water content, superoxide dismutase, peroxidase, and catalase activities, and soluble sugar content of the blades and decreased the relative electroconductivity conductivity and proline, malondialdehyde, hydrogen peroxide, and superoxide anion contents. A comprehensive analysis showed that spraying the plants with exogenous melatonin could increase the activity of antioxidant enzymes and the accumulation of osmotic adjustment substances in C. esculentus blades under salt and drought stress, effectively remove excessive reactive oxygen species, alleviate oxidative damage, and enhance the ability of C. esculentus to resist salt and drought stress.

Living under natural conditions of ocean acidification entails energy expenditure and oxidative stress in a mussel species

We investigated the health conditions of the Mediterranean mussel Mytilus galloprovincialis recruited in the CO2 vents system of Castello Aragonese at Ischia Island (Mediterranean Sea). Individuals of M. galloprovincialis were sampled in three sites along the pH gradient (8.10, 7.7 and up to <7.4). Untargeted metabolomics and biochemical endpoints related to energetic metabolism, oxidative stress/damage, neurotoxicity and immune defense were analyzed. Corrosion of the valves occurred at low pH. A separation of the metabolome was observed along the pH gradient. Metabolites belonging to amino acids, nucleosides, lipids and organic osmolytes were significantly reduced in the organisms from the most acidified sites. The content of reactive oxygen species and the activity of glutathione peroxidase were reduced in organisms from the acidified sites compared to ambient pH, and no oxidative damage was induced. Overall results suggested the presence of an energy cost underpinning long-term survival in acidified conditions for this species.

Cascade Self-Generation of Carbon Monoxide Triggered by Photoinduced Holes for Efficient Hypoxic Tumors Therapy.

It still remains challenging to design multifunctional therapeutic reagents for effective cancer therapy under a unique tumor microenvironment including insufficient endogenous H2O2 and O2, low pH, and a high concentration of glutathione (GSH). In this work, a CO-based phototherapeutic system triggered by photogenerated holes, which consisted of ionic liquid (IL), the CO prodrug Mn2(CO)10, and iridium(III) porphyrin (IrPor) modified carbonized ZIF-8-doped graphitic carbon nitride nanocomposite (IL/ZCN@Ir(CO)), was designed for cascade hypoxic tumors. Upon light irradiation, the photogenerated holes on IL/ZCN@Ir(CO) oxidize water into H2O2, which subsequently induces Mn2(CO)10 to release CO. Meanwhile, IrPor can convert H2O2 to hydroxyl radical (•OH) and subsequent singlet oxygen (1O2), which further triggers CO release. Moreover, the degraded MnO2 shows activity for glutathione (GSH) depletion and mimics peroxidase, leading to GSH reduction and •OH production in tumors. Thus, this strategy can in situ release high concentrations of CO and reactive oxygen species (ROS) and deplete GSH to efficiently induce cell apoptosis under hypoxic conditions, which has a high inhibiting effect on the growth of tumors, offering an attractive strategy to amplify CO and ROS generation to meet therapeutic requirements in cancer treatment.

Physiological and transcriptomic responses of silkworms to graphene oxide exposure

The growing use of nanomaterials has sparked significant interest in assessing the insect toxicities of nanoparticles. The silkworm, as an economically important insect, serves as a promising model for studying how insects respond to harmful substances. Here, we conducted a comprehensive investigation on the impact of graphene oxide (GO) on silkworms using a combination of physiological and transcriptome analyses. GO can enter the midguts and posterior silk glands of silkworms. High GO concentrations (> 25 mg/L) significantly (P < 0.01) inhibited larval growth. Additionally, GO (> 5 mg/L) significantly reduced the cocooning rate, and GO (> 15 mg/L) hindered oviduct development and egg laying in silkworms. GO increased the reactive oxygen species content and regulated catalase activity, suggesting that it may affect insect growth by regulating reactive oxygen detoxification. The transcriptome data analysis showed that 35 metabolism-related genes and 20 ribosome biogenesis-related genes were differentially expressed in response to GO, and their expression levels were highly correlated. Finally, we propose that a Ribosome biogenesis–Metabolic signaling network is involved in responses to GO. The research provides a new perspective on the molecular responses of insects to GO.

Histology, fatty acid composition, antioxidant and glycolipid metabolism, and transcriptome analyses of the acute cold stress response in Phoxinus lagowskii

Water temperature is a crucial environmental factor that significantly affects the physiological and biochemical processes of fish. Due to the occurrence of cold events in aquaculture, it is imperative to investigate how fish respond to cold stress. This study aims to uncover the mechanisms responds to acute cold stress by conducting a comprehensive analysis of the histomorphology, glycolipid metabolic and antioxidant enzymes, fatty acid composition and transcriptome at three temperatures (16 °C, 10 °C and 4 °C) in Phoxinus lagowskii. Our results showed that cold stress not damaged muscle microstructure but caused autophagy (at 10 °C). In addition, serum glucose (Glu) and triglycerides (TG) increased during cold stress. The activities of reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), fructose phosphokinase (PFK), hexokinase (HK), pyruvate kinase (PK), and malondialdehyde (MDA) content in muscle were measured and analyzed. During cold stress, superoxide dismutase and catalase activities increased, reactive oxygen species content decreased. No significant difference in Glutathione peroxidase (GPx) activity, malondialdehyde and total cholesterol (T-CHO) contents among groups. Phosphokinase and pyruvate kinase activities decreased, and HK activity increased during cold stress. Our study resulted in the identification of a total of 25,400 genes, with 2524 genes showing differential expression across different temperature treatments. Furthermore, KEGG pathway indicated that some pathways upregulated during light cold stress (at 10 °C, including autophagy, and AMP-activated protein kinase (AMPK) signaling pathway. Additionally, circadian rhythm is among the most enriched pathways in genes up-regulated during severe cold stress (at 4 °C). Our findings offer valuable insights into how cold-water fish respond to cold stress.

Dynamics of 'Candidatus Liberibacter asiaticus' Growth, Concentrations of Reactive Oxygen Species, and Ion Leakage in Huanglongbing-Positive Sweet Orange.

Citrus Huanglongbing (HLB) caused by 'Candidatus Liberibacter asiaticus' (CLas) is the most devastating citrus disease worldwide. CLas induces systemic and chronic reactive oxygen species (ROS) production, which has been suggested to be a primary cause of cell death in phloem tissues and subsequent HLB symptoms. Mitigating oxidative stress caused by CLas using horticultural approaches has been suggested as a useful strategy to reduce HLB damages. To provide information regarding the application timing to mitigate ROS, we investigated monthly dynamics of CLas concentration, CLas-triggered ROS, and phloem cell death in the bark tissues of asymptomatic and symptomatic branches of HLB-positive Hamlin and Valencia sweet orange trees in the field. Healthy branches in the screenhouse were used as controls. CLas concentration exhibited significant variations over the course of the year, with two distinct peaks observed in Florida citrus groves-late spring/early summer and late fall. Within both Hamlin and Valencia asymptomatic tissues, CLas concentration demonstrated a negative correlation with the deviation between the monthly average mean temperature and the optimal temperature for CLas colonization in plants (25.7°C). However, such a correlation was not evident in symptomatic tissues of Hamlin or Valencia sweet oranges. ROS levels were consistently higher in symptomatic or asymptomatic branches than in healthy branches in most months. ROS concentrations were higher in symptomatic branches than in asymptomatic branches in most months. CLas triggered significant increases in ion leakage in most months for asymptomatic and symptomatic branches compared with healthy controls. In asymptomatic branches of Hamlin, a positive correlation was observed between CLas concentration and ROS concentrations, CLas concentration and ion leakage levels, as well as ROS and ion leakage. Intriguingly, such a relationship was not observed in Valencia asymptomatic branches or in the symptomatic branches of Hamlin and Valencia. This study sheds light on the pathogenicity of CLas by providing useful information on the temporal dynamics of ROS production, phloem cell death, and CLas growth, as well as provides useful information in determining the timing for application of antioxidants and antimicrobial agents to control HLB.

Anti-fouling coating with ROS-Triggered On-Demand regulation of inflammation to favor tissue healing on vascular devices

Unhealthy vascular tissue healing after stenting is primarily triggered by endothelial dysfunction and excessive smooth muscle cell proliferation, which is induced and aggravated by local thrombosis and excessive inflammation. Excessive inflammatory response is closely related to elevated concentrations of reactive oxygen species (ROS). Here, an environment-friendly coating strategy termed “Anti-fouling plus” with inflammatory self-regulation ability was proposed. Upon this, membrane-mimicking copolymer MA(PCLA) served as the antifouling coating, effectively inhibiting coagulation and inflammation during the early stage of implantation. Furthermore, a ROS-responsive prodrug was drawn into the coating to promote tissue healing. A molecular prodrug of thioketal-bearing dexamethasone was engineered to be released in a controlled and responsive manner in response to externally high levels of ROS. The released dexamethasone exhibited highly effective anti-inflammation properties after implantation. The combination of ROS-responsive prodrug and membrane-mimicking antifouling interface strategy intelligently integrated inflammation responsiveness and regulation, which could mediate a gentle vascular microenvironment and thus promote vascular remodeling. In vivo stent implantation studies demonstrated that the proposed “Anti-fouling plus” coating effectively inhibited neointima hyperplasia, modulated the inflammatory response and promoted endothelialization, offering promising surface modification approaches for vascular stents.

Melatonin reduces oxidative stress and improves follicular morphology in feline (Felis catus) vitrified ovarian tissue

Ovarian tissue vitrification is associated with multiple events that promote accumulation of ROS (reactive oxygen species) which culminate in follicular apoptosis. Thus, this study was aimed at evaluating the role of melatonin in vitrification and culture of feline (Felis catus) ovarian tissue. In phase 1, domestic cat ovaries were fragmented into equal circular pieces of 1.5 mm diameter by 1 mm thickness and divided into four groups (fresh control and 3 treatments). The treatments were exposed to vitrification solutions supplemented with melatonin at 0 M, 10−9 M, and 10−7 M, then vitrified-warmed, histologically evaluated and assayed for ROS. Consequently, phase 2 experiment was designed wherein ovarian fragments were divided into two groups. One group was exposed to vitrification solution without melatonin and the other with 10−7 M melatonin supplementation, then vitrified-warmed and cultured for ten days with fresh ovarian fragments as control prior to assessment for histology, immunohistochemistry (Ki-67, MCM-7 and caspase-3) and ROS. Concentration of ROS was lower (p = 0.0009) in 10−7 M supplemented group in addition to higher proportion of grade 1 follicles. After culture, proportions of intact and activated follicles were higher (p < 0.05) in melatonin supplemented group evidenced by higher expression of Ki-67 and MCM-7. Follicular apoptosis was lower in melatonin supplemented group. In conclusion, melatonin at 10−7 M concentration preserved follicular morphological integrity while reducing ROS concentration in vitrified-warmed feline ovarian tissue. It has also promoted the follicular viability and activation with reduced apoptosis during in vitro culture of vitrified-warmed feline ovarian tissue.

Naringin ameliorates H2O2-induced oxidative damage in cells and prolongs the lifespan of female Drosophila melanogaster via the insulin signaling pathway

Naringin exists in a wide range of Chinese herbal medicine and has proven to possess several pharmacological properties. In this study, PC12, HepG2 cells, and female Drosophila melanogaster were used to investigate the antioxidative and anti-aging effects of naringin and explore the underlying mechanisms. The results showed that naringin inhibited H2O2-induced decline in cell viability and decreased the content of reactive oxygen species in cells. Meanwhile, naringin prolonged the lifespan of flies, enhanced the abilities of climbing and the resistance to stress, improved the activities of antioxidant enzymes, and decreased malondialdehyde content. Naringin also improved intestinal barrier dysfunction and reduced abnormal proliferation of intestinal stem cells. Moreover, naringin down-regulated the mRNA expressions of inr, chico, pi3k, and akt-1, and up-regulated the mRNA expressions of dilp2, dilp3, dilp5, and foxo, thereby activating autophagy-related genes and increasing the number of lysosomes. Furthermore, the mutant stocks assays and computer molecular simulation results further indicated that naringin delayed aging by inhibiting the insulin signaling (IIS) pathway and activating the autophagy pathway, which was consistent with the result of network pharmacological predictions.

Lutein-stevioside nanoparticle attenuates H2O2-induced oxidative damage in ARPE cells

In order to improve the bioavailability of lutein (LUT), a novel lutein-stevioside nanoparticle (LUT-STE) were prepared previously, but the information about LUT-STE on protecting of eye health was limited. This study investigated the effect of LUT-STE on antioxidant activity of H2O2-induced human retinal pigment epithelial (ARPE) cells. LUT and LUT-STE (final concentration of 5 μg/mL) significantly enhanced cell viability from (74.84 ± 5.10)% to (81.92 ± 10.01)% (LUT) and (89.33 ± 4.34)% (LUT-STE), and inhibited the cell apoptosis (P < 0.05). After pretreatment with LUT-STE in ARPE cells, the levels of superoxide dismutase (SOD), catalase (CAT) and glutathion peroxidase (GSH-Px) in ARPE cells were significantly increased (P < 0.05), the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) were decreased. In addition, the vascular endothelial growth factor (VEGF) levels were inhibited by 13.61 % and 17.39 %, respectively, pretreatment with LUT and LUT-STE. Western blotting results showed that the pretreatment with LUT-STE inhibited the expression of caspase-9 and caspase-3 and up-regulated Bcl-2/Bax pathway to inhibit H2O2-induced apoptosis. In summary, the novel delivery LUT-STE had more pronounced inhibitory effect on H2O2-induced damage in human ARPE cells.

Phytochemicals from the rhizome of Bletilla formosana and their antioxidant, cytoprotective and anti-inflammatory activities

Bletilla formosana (Hayata) Schltr, popularly known as "Xiao Baiji", is commonly consumed as a food ingredient and herbal medicine with the treatment of haemorrhages, chapped skin, colds, and burns in China. The phytochemical investigation of B. formosana rhizomes result in the isolation and identification of 35 chemical compounds, of which biphenyl, phenanthrene and their derivatives are the most abundant structural types. Among the isolated compounds, 12 compounds showed superior antioxidative activities in Ferric reducing/antioxidant power (FRAP), 2,2-diphenyl-1-picryhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging assay. Furthermore, compounds 18-20 (phenanthrenes) and 34 (lignin) had significantly antioxidant capacity and cytoprotective effects through decreasing reactive oxygen species (ROS) content and up-regulating the levels of catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH) in H2O2-induced HepG2 cells. In addition, compounds 8, 10, 16 (dihydrophenanthrenes), 18-20 (phenanthrenes), 27-28 (phenolics), 34-35 (lignin) showed the significant anti-inflammatory by inhibiting productions of interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the lipopolysaccharide (LPS)-induced RAW264.7 macrophage cells. These results confirmed most of isolated compounds displayed significant antioxidant, cytoprotective and anti-inflammatory activities. Among phenanthrenes (18-20) were a prominent type found in the rhizomes of B. formosana. And the more phenolic hydroxyl and methoxy groups of phenanthrene and their derivatives, the better activities. This suggested that Bletilla formosana rhizomes can be used as an edible and medicine homologous plant with antioxidant and anti-inflammatory functions, and can be developed into functional and health nutrition products.

The Metabolism, Detrimental Effects, and Signal Transduction Mechanism of Reactive Oxygen Species in Plants under Abiotic Stress

Plants are a major source of bio based materials, and their productivity is significantly impacted by environmental adversities with the continuous deterioration of the environment. The disruption of reactive oxygen species (ROS) production and scavenging balance is a common consequence of various abiotic stresses in plants, resulting in the excessive accumulation of ROS. However, it is crucial to acknowledging the dual role of ROS, acting both as harmful substances and signaling molecules. ROS can interact with membrane proteins, initiating a chain reaction of membrane lipid peroxidation. This process leads to a decrease in membrane lipid unsaturation and fluidity, as well as an increase in membrane permeability. Inhibited enzyme activity even lead to loss of protein function, caused DNA damage and mutations, blocked DNA replication and transcription, eventually leading to cell death. This can result in significant reductions in crop yield and biomass in bio based agricultural production. ROS also played vital role in signal molecule transduction in the process of plant resistance to stress, and worked in concert with other signal molecules to induce the stress resistance genes’ expression and enhance plant resistance. Hereto, scavenging mechanism for ROS in plants is of the essence to regulate the concentration of ROS, thus determining which role ROS play. The thermal dissipation of excess light energy effectively avoids ROS production, and the enzymatic and non-enzymatic antioxidant defense systems in plants work cooperatively to clear excessive ROS. This review provides a comprehensive summary of the production pathway, detrimental effects, scavenging mechanism and signal transduction of ROS in plants under abiotic stress.

The effects of acteoside on locomotor recovery after spinal cord injury – The role of autophagy and apoptosis signaling pathway

In the current study, we investigated the effects of acteoside as a phenylpropanoid glycoside on interaction with neurons to assesses locomotor recovery after spinal cord injury (SCI) in rats by focusing on evaluating the factors involved in autophagy, apoptosis, inflammation and oxidative stress processes. 49 Spargue-Dawley rats were prepared and divided into seven healthy and SCI groups receiving different concentrations of acteoside. After 28 days of disease induction and treatment with acteoside, a BBB score test was used to evaluate locomotor activity. Then, by preparing spinal cord cell homogenates, the expression levels of MAP1LC3A, MAP-2, glial fibrillary acidic protein (GFAP), Nrf2, Keap-1, Caspase 3 (Casp3), Bax, Bcl-2, TNF-a, IL-1B, reactive oxygen species (ROS), and malondialdehyde (MDA) were measured. Improvement of locomotor activity in SCI rats receiving acteoside was observed two weeks after the beginning of the experiment and continued until the fourth week. Both MAP1LC3A and MAP-2 were significantly up-regulated in SCI rats treated with acteoside compared to untreated SCI rats, and GFAP levels were significantly decreased in these animals. Pro-apoptotic proteins Bax and Casp3 and anti-apoptotic protein Bcl-2 were down-regulated and up-regulated, respectively, in SCI rats receiving acteoside. In addition, a significant downregulation of iNOS, TNF-α, and IL-1β and a decrease in contents of both ROS and MDA as well as increases in Nrf2 and Keap-1 were seen in rats receiving acteoside. Furthermore, acteoside strongly interacted with MAP1LC3A, TNF-α, and Casp3 targets with binding affinities of −8.3 kcal/mol, −8.3 kcal/mol, and −8.5 kcal/mol, respectively, determined by molecular docking studies. In general, it can be concluded that acteoside has protective effects in SCI and can be considered as an adjuvant therapy in the treatment of this disease. However, more studies, especially clinical studies, are needed in this field.

The Responses of Pollen Tubes to Spermidine Treatments in Actinidia deliciosa

In this study, the responses of pollen tubes to spermidine treatments (10 µM, 25 µM, 50 µM, 100 µM, 250 µM, or 500 µM) were investigated in Actinidia deliciosa, by focusing on pollen germination rate, pollen tube length, organizations of actin filaments, concentrations of Ca+2, pH, reactive oxygen species and distributions of callose and cellulose. According to findings, the only positive effect was detected after 10 µM spermidine treatment while the most negative acute effect was detected after 500 µM spermidine treatment and, further experiments were done in these groups. 10 µM spermidine increased the pollen tube length by changing the concentration of apex localized reactive oxygen species. 500 µM spermidine decreased the pollen tube length by changing the apex localized Ca+2, pH, and reactive oxygen species concentration. Findings would contribute to the understanding of the effects of polyamines on pollen tubes.

Pirarucu requires taurine to maximize growth and antioxidant status when fed diets high in plant-based ingredients

Taurine (Tau) is a free conditionally essential amino acid for most fish species that plays a significant nutritional role, mainly in carnivorous fish species. However, limited studies are still available regarding the role of Tau on pirarucu nutrition, an important Amazonian fish species. Therefore, this study used diets high in plant-based ingredients to investigate the effect of taurine (Tau) supplementation on juvenile pirarucu's growth, metabolism, and health (n = 115, Weight = 504.12 ± 19 g). Fish were fed five diets containing increasing levels of Tau: 0.95, 5.1, 9.6, 12.9, and 17.2 g/kg in a completely randomized design with three replicates per treatment. After a 60-day feeding trial, growth, hematology, blood chemistry, Tau content in muscle, carcass, and liver, antioxidant status, and immunological parameters were evaluated. The control group (0.95 g/kg Tau) showed the lowest growth. According to the segmented regression model, the recommended Tau level for maximizing the development of juvenile pirarucu was 4.49 g/kg of feed. Additionally, fish fed the lowest dietary Tau level showed the highest ROS (reactive oxygen species) concentration. Dietary Tau levels did not affect hematological parameters and blood chemistry (p > 0.05). Fish fed 9.6 g/kg of Tau showed increased catalase activity, while the control group had the worst result in NBT (nitroblue tetrazolium reduction test). Fish fed with the highest dietary Tau levels (12.9 and 17.2 g/kg) showed increased total serum immunoglobulin concentration. These results suggest that the optimal inclusion level of Tau in diets for juvenile pirarucu is 4.49 g/kg of feed and that this amino acid acts as a mitigator of oxidative stress.

TROP2 promotes PINK1-mediated mitophagy and apoptosis to accelerate the progression of senile chronic obstructive pulmonary disease by up-regulating DRP1 expression

Chronic obstructive pulmonary disease (COPD) is a chronic airway inflammatory disease characterised by irreversible airflow limitation. The elderly are a vulnerable population for developing COPD. With the growth of age, physiological degenerative changes occur in the thorax, bronchus, lung and vascular wall, which can lead to age-related physiological attenuation of lung function in the elderly, so the prevalence of COPD increases with age. Its pathogenesis has not yet been truly clarified. Mitophagy plays an important role in maintaining the stability of mitochondrial function and intracellular environment by scavenging damaged mitochondria. Currently, studies have shown that trophoblast antigen 2 (TROP2) expression is up-regulated in airway basal cells of patients with COPD, suggesting that TROP2 is involved in the progression of COPD. However, whether it is involved in disease progression by regulating mitochondrial function remains unclear. In this study, compared with non-smoking non-COPD patients, the expression of TROP2 in lung tissues of smoking non-COPD patients and patients with COPD increased, and TROP2 expression in patients with COPD was higher than that in smoking non-COPD patients. To further explore the role of TROP2, we stimulated BEAS-2B with cigarette smoke to construct an in vitro model. We found that TROP2 expression increased, whereas TROP2 silencing reversed the cigarette smoke extract-induced decrease in mitochondrial membrane potential, increased reactive oxygen species content, decreased adenosine triphosphate (ATP) production, increased inflammatory factor secretion and increased apoptosis. In addition, we searched online bioinformatics and screened the gene dynamin-related protein 1 (DRP1) related to mitophagy as the research object. Co-IP assay verified the binding relationship between DRP1 and TROP2. Further study found that TROP2 promoted mitophagy and apoptosis of BEAS-2B cells by up-regulating the expression of DRP1. In addition, PTEN-induced putative kinase 1 (PINK1) is a potential binding protein of DRP1, and DRP1 accelerated mitophagy and apoptosis of BEAS-2B cells by promoting the expression of PINK1. We established a COPD SD rat model by cigarette smoke exposure and LPS instillation and treated it by intraperitoneal injection of si-TROP2. The results showed that TROP2 silencing restored lung function and reduced the secretion of inflammatory factors in bronchoalveolar lavage fluid. In conclusion, TROP2 can be used as a new reference for COPD treatment.

Photocatalytic degradation of ammonia to nitrogen by anatase TiO2 under microwave discharge electrodeless lamp irradiation

In this study, a microwave discharge electrodeless lamp (MDEL) photo-degradation system coupled with anatase TiO2 (P25) was constructed to improve the selective degradation of NH3 to N2. The MDEL system can generate abundant reactive oxygen species (ROS) with ultraviolet radiation at 185 nm and 254 nm during gas phase reaction. The species and content of ROS generated in the reaction system were determined by oxidation extraction spectrophotometry, and the effects of residence time, temperature, and relative humidity on the production of reactive oxygen species were investigated. In addition, the removal efficiency under different conditions such as initial ammonia concentration, relative humidity and residence time was explored. It was found that the removal rate could reach 83% when the initial ammonia concentration was 100 ppm, relative humidity was 55% and gas residence time was 5.16 s. The high-energy ultraviolet at 185 nm from MDEL could break NH3 molecules in advance and produced a large amount of ·NH2. Besides, NH3 was converted to N2 by generating large amounts of ROS, reducing NOx and nitrate generation. Our work presents a novel approach to construct a photocatalytic system for high efficiency degradation of NH3.

Abrogating PDK4 activates autophagy-dependent ferroptosis in breast cancer via ASK1/JNK pathway

BackgroundTargeting ferroptosis mediated by autophagy presents a novel therapeutic approach to breast cancer, a mortal neoplasm on the global scale. Pyruvate dehydrogenase kinase isozyme 4 (PDK4) has been denoted as a determinant of breast cancer metabolism. The target of this study was to untangle the functional mechanism of PDK4 in ferroptosis dependent on autophagy in breast cancer.MethodsRT-qPCR and western blotting examined PDK4 mRNA and protein levels in breast cancer cells. Immunofluorescence staining appraised light chain 3 (LC3) expression. Fe (2 +) assay estimated total iron level. Relevant assay kits and C11-BODIPY (591/581) staining evaluated lipid peroxidation level. DCFH-DA staining assayed intracellular reactive oxygen species (ROS) content. Western blotting analyzed the protein levels of autophagy, ferroptosis and apoptosis-signal-regulating kinase 1 (ASK1)/c-Jun N-terminal kinase (JNK) pathway-associated proteins.ResultsPDK4 was highly expressed in breast cancer cells. Knockdown of PDK4 induced the autophagy of breast cancer cells and 3-methyladenine (3-MA), an autophagy inhibitor, countervailed the promoting role of PDK4 interference in ferroptosis in breast cancer cells. Furthermore, PDK4 knockdown activated ASK1/JNK pathway and ASK1 inhibitor (GS-4997) partially abrogated the impacts of PDK4 absence on the autophagy and ferroptosis in breast cancer cells. ConclusionTo sum up, deficiency of PDK4 activated ASK1/JNK pathway to stimulate autophagy-dependent ferroptosis in breast cancer.