Free Radical Generation Research Articles

Structural, bacteriostatic and antioxidant profiling of zinc oxide nanoparticles

The bacterial infection and generation of free radicals inside the body are serious threats to human health globally and researchers show their serious concern for these issues. Thus, in this study, an attempt has been made to control bacterial growth and scavenge the ABTs free radicals. ZnO-NPs were synthesized by an economical method, and the characteristics were investigated using a range of analytical techniques. These methods included FTIR, SEM, EDX, XRD, and TEM. The agar-well diffusion process has been followed to control the growth of selected bacteria and the ABTs free radicals have been scavenged using a standard protocol. The effect of the dose on both activities has been studied where the results has explore that the effectiveness of the ZnO-NPs gradually increases with increasing concentration.

Effect of quercetin and mirtazapine on spermatogenesis and testis structure in phenylhydrazine-induced hemolytic anemia mice: An experimental study

Anemia poses a significant healthcare challenge across different socioeconomic groups and can result in reproductive system damage through the generation of free radicals and lipid peroxidation. This study examines the protective effects of quercetin (QUE) and mirtazapine (MIR) against the reproductive damage caused by phenylhydrazine (PHZ) in mice. Fifty NMRI mice, aged 8–10 weeks with an average weight of 27.0 ± 2.0 g, were randomly divided into five groups. The control group (Group 1) received oral administration of 10 mL/kg/day of normal saline. Group 2 (PHZ group) received an initial intraperitoneal dose of 8 mg/100 g body weight of PHZ, followed by subsequent doses of 6 mg/100 g every 48 h. Group 3 received PHZ along with oral QUE at a dosage of 50 mg/kg/day. Group 4 received PHZ along with oral MIR at a dosage of 30 mg/kg/day. Group 5 received PHZ along with oral QUE at a dosage of 50 mg/kg/day and MIR at a dosage of 30 mg/kg/day. The treatment duration was 35 days. Sperm samples were collected from the caudal region of the epididymis post-euthanasia to assess the total mean sperm count, sperm viability, motility, DNA damage, and morphology. Testicular tissue was employed to quantify total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) concentrations, while serum levels of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were analyzed. Additionally, various aspects, including testicular histopathology, oxidative enzyme levels, gene expression related to apoptosis and antiapoptotic pathways, and in vivo fertility index, were evaluated after 35 days. The QUE, MIR, and QUE + MIR groups showed less abnormal morphology and DNA damage, as well as better total and progressive sperm motility, motility characteristics, viability, and plasma membrane function compared to the PHZ group. QUE, MIR, and QUE + MIR administration increased TAC, SOD, and GPx activities in testicular tissue, while reducing MDA levels compared to the PHZ group. Furthermore, QUE, MIR, and QUE + MIR significantly reduced Bax, and caspase-3 expression levels, and increased Bcl-2 expression levels, compared to the PHZ group. Mice treated with QUE, MIR, and QUE + MIR exhibited an increased in vivo fertility index and plasma sex hormone levels compared to the PHZ group. These results show that QUE, MIR, and QUE + MIR might be able to improve the fertility index, boost the testicular antioxidant defense system, and control the death of germ cells. This could mean that they could be used to treat mice with PHZ-induced testicular damage.

Dual electron microregion with oxygen vacancy of Fe0.8La/MCM-48 in bridging peracetic acid and ozonation: Taking the pathway of free radical or nonradical generation?

Efficient tetracycline hydrochloride (TCH) degradation and interface reaction mechanism were investigated by constructing nonradical pathways in heterogeneous peracetic acid coupling with ozonation (O3/PAA) process. Ball-milling assisted Fe–La anchoring MCM-48 catalysts with dual electron microregion was designed to trigger 1O2-dominated non-radical for strong immunity to environment interference. Results exhibited that 83.4% degradation efficiency of TCH was achieved by Fe0.8La/MCM-48/O3/PAA system in only 2 min and 94% TCH was degraded in a 12-hour continuous flow experiment. La with oxygen vacancy regulated the local atomic environment and electron structure of Fe sites, which could initiate peracetic acid activation to promote 1O2 production by surface adsorbed atomic oxygen (*Oad) reaction and this process overcame a lower reaction energy barrier than the binding of surface *Oad to O3. This work offers a reasonable interpretation for Fe–La synergy for inducing non-free radical route, which furnishes theoretical support and practical application for heterogeneous O3/PAA.

Graphene acid quantum dots: A highly active multifunctional carbon nano material that intervene in the trajectory towards neurodegeneration

Carbon dots (CDs) are carbon nano materials (CNMs) that find use across several biological applications because of their water solubility, biocompatible nature, eco-friendliness, and ease of synthesis. Additionally, their physiochemical properties can be chemically tuned for further optimization towards specific applications. Here, we investigate the efficacy of C70-derived Graphene Acid Quantum Dots (GAQDs) in mitigating the transformation of soluble, monomeric Hen Egg-White Lysozyme (HEWL) to mature fibrils during its amyloidogenic trajectory. Our findings reveal that GAQDs exhibit dose-dependent inhibition of HEWL fibril formation (up to 70 % at 5 mg/mL) without affecting mitochondrial membrane potential or inducing apoptosis at the same density. Furthermore, GAQDs scavenged reactive oxygen species (ROS); achieving a 50 % reduction in ROS levels at a mere 100 µg/mL when exposed to a standard free radical generator. GAQDs were not only found to be biocompatible with a human neuroblastoma-derived SHSY-5Y cell line but also rescued the cells from rotenone-induced apoptosis. The GAQD-tolerance of SHSY-5Y cells coupled with their ability to restitute cells from rotenone-dependent apoptosis, when taken in conjunction with the biocompatibility data, indicate that GAQDs possess neuroprotective potential. The data position this class of CNMs as promising candidates for resolving aberrant cellular outputs that associate with the advent and progress of multifactorial neurodegenerative disorders including Parkinson’s (PD) and Alzheimer’s diseases (AD) wherein environmental causes are implicated (95 % etiology). The data suggest that GAQDs are a multifunctional carbon-based sustainable nano-platform at the intersection of nanotechnology and neuroprotection for advancing green chemistry-derived, sustainable healthcare solutions.

Cationic Europium-Organic Framework for Chromatographic Column Separation of Ionic Dyes and Stimuli-Responsive Chromic Properties.

A novel 3D europium-based cationic framework (Eu-CMOF) has been constructed solvothermally by employing a viologen derivative as an organic functional building unit. Notably, Eu-CMOF demonstrates its capability as a proficient aqueous-phase ion-exchange host, facilitating the remarkable rapid chromatographic column separation of new coccine and malachite green (NC3-/MG+), as well as new coccine and methylene blue (NC3-/MLB+), in mere 2 to 4 min. Adsorption thermodynamics and kinetics of anionic dyes demonstrate that Eu-CMOF exhibits a higher adsorption capacity for NC3-, as evaluated by the Langmuir model, reaching a value of 173 mg·g-1. The pseudo-second-order rate constant is determined to be 3.84 × 10-3 mg-1·g·min-1. Additionally, Eu-CMOF displays reversible photochromic and amine- and ammonia-induced vapochromic behaviors. Further mechanistic studies reveal that these chromic behaviors are primarily attributed to the generation of free viologen radical stimulated by Xe-light or electron-rich amine/ammonia. This research contributes to the development of advanced materials with applications in rapid chromatographic separation and stimuli-responsive chromic properties, showcasing the potential of Eu-CMOF as a versatile platform for practical applications.

Reproductive Ageing: Metabolic contribution to age-related chromosome missegregation in mammalian oocytes.

Chromosome missegregation and declining energy metabolism are considered to be unrelated features of oocyte ageing that contribute to poor reproductive outcomes. Given the bioenergetic cost of chromosome segregation, we propose here that altered energy metabolism during ageing may be an underlying cause of age-related chromosome missegregation and aneuploidy. Advanced reproductive age in women is a major cause of infertility, miscarriage and congenital abnormalities. This is principally caused by a decrease in oocyte quality and developmental competence with age. Oocyte ageing is characterised by an increase in chromosome missegregation and aneuploidy. However, the underlying mechanisms of age-related aneuploidy have not been fully elucidated and are still under active investigation. In addition to chromosome missegregation, oocyte ageing is also accompanied by metabolic dysfunction. In this review, we integrate old and new perspectives on oocyte ageing, chromosome segregation and metabolism in mammalian oocytes and make direct links between these processes. We consider age-related alterations to chromosome segregation machinery, including the loss of cohesion, microtubule stability and the integrity of the spindle assembly checkpoint. We focus on how metabolic dysfunction in the ageing oocyte disrupts chromosome segregation machinery to contribute to and exacerbate age-related aneuploidy. More specifically, we discuss how mitochondrial function, ATP production and the generation of free radicals are altered during ageing. We also explore recent developments in oocyte metabolic ageing, including altered redox reactions (NAD+ metabolism) and the interactions between oocytes and their somatic nurse cells. Throughout the review, we integrate the mechanisms by which changes in oocyte metabolism influence age-related chromosome missegregation.

Iron coupled with hydroxylamine turns on the “switch” for free radical degradation of organic pollutants under high pH conditions

Reducing iron by hydroxylamine (HA) can promote the generation of reactive oxygen species (ROS) in the Fenton reaction and play a crucial role in the degradation of organic pollutants. However, the performance of this system at wider environmental thresholds is still not sufficiently understood, especially in the highly alkaline environments resulting from human activities. Here, we assessed the impact of solution pH on organic pollutant degradation by goethite with the addition of HA and H2O2. The solid phase variation and ROS generation were analyzed using Mössbauer spectroscopy, X-ray absorption near edge structure spectroscopy, and electron paramagnetic resonance analysis. This study found that under alkaline conditions, the system can continuously scavenge organic pollutants through oxygen-mediated generation of free radicals. At lower pH levels, organic pollutant decomposition, exemplified by the breakdown of bisphenol A (BPA), is primarily driven by the Fenton reaction facilitated by iron. As pH increases, hydroxyl radical (•OH) production decreases, accompanied by decreased BPA removal efficiency. However, the removal efficiency of BPA increased significantly at pH > 9. At pH 12, the removal of BPA exceeded that of the acidic condition after one hour, which is consistent with observations in soil system studies. Unlike the Fenton reaction, which is not sensitive to oxygen content, the removal of BPA under alkaline conditions occurs only under aerobic conditions. H2O2 is hardly involved in the reaction, and the depletion of HA becomes a critical factor in the decomposition of BPA. Importantly, in contrast to acidic conditions, where the dramatic decomposition of BPA occurs mainly in the first 10 min, the decomposition of BPA under alkaline conditions continued to occur over the 2 h of observation until complete removal. For natural systems, the remediation of pollutants depends more on the active time of ROS than on their reactivity. Therefore, this idea can reference pollution remediation strategies in anthropogenically disturbed environments.

Exposure to low-concentration fipronil impairs survival, behavior, midgut morphology and physiology of Aedes aegypti larvae

The Aedes aegypti mosquito is a vector for various arboviruses, including dengue and yellow fever. Insecticides, such as pyrethroids and organophosphates, are widely used to manage and control these insects. However, mosquitoes have developed resistance to these chemicals. Therefore, this study aimed to investigate the effects of the commercial formulation of fipronil (Tuit® Florestal; 80% purity) on the survival, behavior, morphology, and proteins related to signaling pathways of the midgut in A. aegypti larvae under controlled laboratory conditions. Significant reductions in immature survival were observed in all concentrations of fipronil tested. Low insecticide concentration (0.5 ppb) led to decreased locomotor activity in the larvae and caused disorganization of the epithelial tissue in the midgut. Moreover, exposure to the insecticide decreased the activity of detoxifying enzymes such as catalase, superoxide dismutase, and glutathione-S-transferase. On the other hand, the insecticide increased protein oxidation and nitric oxide levels. The detection of LC3, caspase-3, and JNK proteins, related to autophagy and apoptosis, increased after exposure. However, there was a decrease in the positive cells for ERK 1/2. Furthermore, the treatment with fipronil decreased the number of positive cells for the proteins FMRF, Prospero, PH3, Wg, Armadillo, Notch, and Delta, which are related to cell proliferation and differentiation. These findings demonstrate that even at low concentrations, fipronil exerts larvicidal effects on A. aegypti by affecting behavior and enzymatic detoxification, inducing protein oxidation, free radical generation, midgut damage and cell death, and inhibiting cell proliferation and differentiation. Thus, this insecticide may represent a viable alternative for controlling the spread of this vector.

Nanoplastics induced health risk: Insights into intestinal barrier homeostasis and potential remediation strategy by dietary intervention

Aged nanoplastics (aged-NPs) have unique characteristics endowed by environmental actions, such as rough surface, high oxygen content. Although studies have highlighted the potential hazards of aged-NPs, limited research has provided strategies for aged-NPs pollution remediation. The dietary intervention of quercetin is a novel insight to address the health risks of aged-NPs. This study explored the impact of aged-NPs on intestinal barrier homeostasis at the environmentally relevant dose and investigated the alleviating effects of quercetin on aged-NPs toxicity through transcriptomics and molecular biology analysis. It indicated that aged-NPs induced intestinal barrier dysfunction, which was characterized by higher permeability, increased inflammation, and loss of epithelial integrity, while quercetin restored it. Aged-NPs disrupted redox homeostasis, upregulated inflammatory genes controlled by AP-1, and led to Bax-dependent mitochondrial apoptosis. Quercetin intervention effectively mitigated inflammation and apoptosis by activating the Nrf2. Thus, quercetin decreased intestinal free radical levels, inhibiting the phosphorylation of p38 and JNK. This study unveiled the harmful effects of aged-NPs on intestinal homeostasis and the practicability of dietary intervention against aged-NPs toxicity. These findings broaden the understanding of the NPs toxicity and provide an effective dietary strategy to relieve the health risks of NPs. Environmental ImplicationsGrowing levels of NPs pollution have represented severe health hazards to the population. This study focuses on the toxic mechanism of aged-NPs on the intestinal barrier and the alleviating effect of quercetin dietary intervention, which considers the environmental action and relevant dose. It revealed the harmful effects of aged-NPs on intestinal inflammation with the key point of free radical generation. Furthermore, a quercetin-rich diet holds significant promise for addressing and reversing intestinal damage caused by aged-NPs by maintaining intracellular redox homeostasis. These findings provide an effective dietary strategy to remediate human health risks caused by NPs.

Mitochondrial Peroxiredoxin 6 Declines with Aging in Parallel with Increases in Hydrogen Peroxide Generation

Oxidative stress in cells and tissues arise from an imbalance between the generation of free radicals and the ability to detoxify these reactive oxygen species (ROS). Peroxiredoxins (PRDXs) are a family of widely distributed enzymes that act as master antioxidant regulators by scavenging peroxides and peroxynitrites. The accumulation of oxidative damage from chronic exposure to oxidative stress such as on DNA, mitochondrial proteins, and lipid macromolecules, is postulated to result in age-associated pathologies and physiological dysfunctions. Peroxiredoxin-6 (PRDX6) contributes to the maintenance of redox balance in a variety of tissues from lung to skeletal muscle. Here, we hypothesized that PRDX6 localizes to the mitochondria and plays a significant role in maintaining mitochondrial function through targeting mitochondrially generated ROS, and that gradual loss of mitochondrial PRDX6 contributes to increased oxidative stress and accumulation of oxidative damage during aging. In this study, respiratory rates and complex activities in isolated skeletal muscle mitochondria obtained from young (3-6 months) and old (20-24 months) C57/BL6J mice were compared. Amplex UltraRed fluorescence was used to determine production rates of mitochondrial hydrogen peroxide (H2O2). Western blot analysis was used to compare protein abundance and ELISA was used to measure lipid peroxidation in skeletal muscle mitochondrial fractions. Our findings revealed that isolated mitochondria from skeletal muscle in old mice generated higher rates of H2O2 from complex I (CI) during state 3 and state 4 (State 3; State 4) derived respiration (3.93 ± 0.41; 3.56 ± 0.38 pmol H2O2..s−1.mg−1) compared to young mouse mitochondria (1.57 ± 0.48; 1.89 ± 0.59 pmol H2O2.s−1.mg−1, p ≤ 0.05). This was also found when saturating amounts of ADP were used to stimulate maximal rates of oxygen consumption (old: 3.65 ± 0.77; young 1.40 ± 0.21 pmol H2O2−1.mg−1, p ≤ 0.05). Furthermore, CI activity was found to be lower in isolated mitochondria from old mice (0.65 ± 0.006 U.ug−1) compared to young mice (2.11 ± 0.64 U.ug−1, p ≤ 0.05). Similarly, mitochondrial PRDX6 abundance was lower while levels of lipid peroxidation product malondialdehyde were higher in skeletal muscle from old animals (old: 2712 ± 1320 pg.mL−1; young: 489 ± 225 pg.mL−1). These results show higher mitochondrial ROS generation rates and oxidative damage in old animals. These data also suggest that loss of PRDX6 in aging leads to mitochondrial dysfunction mediated by diminished CI activity and loss of membrane integrity. We are currently conducting mechanistic studies in cellular models with disrupted PRDX6 expression to confirm the effect of this protein in maintaining mitochondrial function. This study offers novel observations on the significance of mitochondrially localized PRDX6 in antioxidant defense as well as the sources and roles of ROS generation in contributing to an aging phenotype. National Institute of General Medical Sciences (NIGMS, Award Number R35GM146951). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

L-serine restored lysosomal failure in cells derived from patients with BPAN reducing iron accumulation with eliminating lipofuscin

Defective mitochondria and autophagy, as well as accumulation of lipid and iron in WDR45 mutant fibroblasts, is related to beta-propeller protein-associated neurodegeneration (BPAN). In this study, we found that enlarged lysosomes in cells derived from patients with BPAN had low enzyme activity, and most of the enlarged lysosomes had an accumulation of iron and oxidized lipid. Cryo-electron tomography revealed elongated lipid accumulation, and spectrometry-based elemental analysis showed that lysosomal iron and oxygen accumulation superimposed with lipid aggregates. Lysosomal lipid aggregates superimposed with autofluorescence as free radical generator, lipofuscin. To eliminate free radical stress by iron accumulation in cells derived from patients with BPAN, we investigated the effects of the iron chelator, 2,2′-bipyridine (bipyridyl, BIP). To study whether the defects in patient-derived cells can be rescued by an iron chelator BIP, we tested whether the level of iron and reactive oxygen species (ROS) in the cells and genes related to oxidative stress were rescued BIP treatment. Although BIP treatment decreased some iron accumulation in the cytoplasm and mitochondria, the accumulation of iron in the lysosomes and levels of cellular ROS were unaffected. In addition, the change of specific RNA levels related to free radical stress in patient fibroblasts was not rescued by BIP. To alleviate free radical stress, we investigated whether l-serine can regulate abnormal structures in cells derived from patients with BPAN through the regulation of free radical stress. l-serine treatment alleviated increase of enlarged lysosomes and iron accumulation and rescued impaired lysosomal activity by reducing oxidized lipid accumulation in the lysosomes of the cells. Lamellated lipids in the lysosomes of the cells were identified as lipofuscin through correlative light and electron microscopy, and l-serine treatment reduced the increase of lipofuscin. These data suggest that l-serine reduces oxidative stress-mediated lysosomal lipid oxidation and iron accumulation by rescuing lysosomal activity.

Carbon bridge effects regulate TiO2-acrylate fluoroboron coatings for efficient marine antifouling

Synergy strategy of photocatalysts and polymer resins are promising technology for marine antifouling. However, it is still a main challenge to obtain a green, safe, and efficient antifouling coatings. Herein, carbon (graphene or CNT) modified TiO2 photocatalyst was synthesized via hydrothermal and annealing process and has successfully applied in acrylate fluoroboron polymer (ABFP) composite coating. Morphology and chemical composition were detailed characterized. The graphene or CNT acted as a bridge with supplemental spatial structures (petal gaps, entanglement) and new functional groups (C-O, C-Ti-O, etc.) on TiO2 particle. Carbon nanotube (CNT) modified TiO2-ABFP coatings (BTCP) achieved excellent antibacterial and anti-diatom adhesion rate of 89.33%-96.70% and 99.00%-99.50%, which was 1.84-4.94-fold more than that of the single ABFP. CNT or graphene served as electronic bridges was considered as the crucial mechanism, which significantly improved the light absorption range and capacity, conductivity, and photoelectric response of TiO2, and further accelerated the generation and transfer of free radicals to the surface of BTCP or FTGP. Moreover, the improvement of catalyst activity synergizes with the smooth surface, hydrophilicity, and slow hydrolysis of composite coatings, achieved long-term and efficient antifouling performance. This work provides a new insight into the modification of TiO2 and antifouling mechanism of polymer coating.

MXene/ZnS/chitosan-cellulose composite with Schottky heterostructure for efficient removal of anionic dyes by synergistic effect of adsorption and photocatalytic degradation

Nowadays, dye water pollution is becoming increasingly severe. Composite of MXene, ZnS, and chitosan-cellulose material (MX/ZnS/CC) was developed to remove anionic dyes through the synergistic effect of adsorption and photocatalytic degradation. MXene was introduced as the cocatalyst to form Schottky heterostructure with ZnS for improving the separation efficiency of photocarriers and photocatalytic performance. Chitosan-cellulose material mainly served as the dye adsorbent, while also could improve material stability and assist in generation of free radicals for dye degradation. The physics and chemistry properties of MX/ZnS/CC composite were systematically inspected through various characterizations. MX/ZnS/CC composite exhibited good adsorption ability to anionic dyes with adsorption capacity up to 1.29 g/g, and excellent synergistic effects of adsorption and photodegradation with synergistic removal capacity up to 5.63 g/g. MX/ZnS/CC composite performed higher synergistic removal ability and better optical and electrical properties than pure MXene, ZnS, chitosan-cellulose material, and MXene/ZnS. After compounding, the synergistic removal percentage of dyes increased by a maximum of 309 %. MX/ZnS/CC composite mainly adsorbs anionic dyes through electrostatic interactions and catalyzes the generation of •O2−, h+, and •OH to degrade dyes, which has been successfully used to remove anionic dyes from environmental water, achieving a 100 % removal of 50 mg/L dye.

Exogenous T4 Increased Cardiac Thioredoxin Protein Expression in Insulin Resistant OLETF Rats

Thioredoxin (Trx) is a protein that regulates cellular signaling and antioxidant defense. Cellular antioxidant mechanisms are designed to protect cells from oxidative damage caused by inappropriately elevated reactive oxygen species (ROS) and other free radicals. Oxidative damage can lead to cellular damage and impaired function. Diabetic cardiomyopathy (CDM) is associated with impaired redox balance and oxidative injury. Altered fuel metabolism is a key feature of CDM characterized by an imbalance in fatty acid and glucose utilization, favoring fatty acid overutilization. Excessive fatty acid beta-oxidation in the mitochondria leads to generation of free radicals including superoxide, which can contribute to oxidative injury. Thyroid hormones regulate substrate utilization and their dysregulation may contribute to oxidative injury. Therefore, we hypothesized that exogenous thyroxine (exoT4) upregulates Trx protein expression and ameliorate oxidative injury in the hearts of insulin resistant rats. Insulin resistant, Otsuka Long Evans Tokushima Fatty (OLETF) rats were used to assess the effects of exoT4 on heart Trx, oxidative damage, and glucose metabolism. Rats were assigned to four groups: (1) lean, control Long Evans Tokushima Otsuka (LETO; n=6), (2) LETO + T4 (8 μg/100g BM/d × 5 wks; n=7), (3) untreated, insulin resistant OLETF (n=6), and (4) OLETF + T4 (n=7). OLETF group displayed a 31% decreased in TRX compared to Leto. T4 increased Trx protein expression by 88% in OLTEF compared to untreated OLETF. This data suggests that exoT4 has the potential to upregulate cardiac Trx-dependent antioxidant mechanisms in insulin resistant OLETF rats to ameliorate oxidative injury and improve cardiac glucose metabolism. This work is supported by the American Heart Association and the Undergraduate Research Opportunity Center (UROC). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Nanotechnology's Applications and Potential in Various Fields.

Since ancient times, several sorts of nanoparticles have been employed in the quickly expanding field of nanotechnology. These features include size, shape, and chemical as well as physical properties.Because of their small size and huge surface area, carbon-based nanoparticles, including fullerenes, carbon nanotubes, graphene, graphene oxide, and carbon-based quantum dots, have attracted a lot of attention in a variety of sectors, including biomedical applications. Lipid bilayers form the spherical vesicles known as liposomes. Magnetic resonance imaging (MRI) contrast agents are iron oxide nanoparticles. These materials are perfect for drug and delivery of genes, bioimaging, and bone repair because of their remarkable mechanical, electrical, visual, and chemical properties. However, concerns about potential asbestos-related diseases have arisen due to their length-to-width aspect ratio. Ceramic nanoparticles, on the other hand, are a common material in daily life and play a crucial role in bone repair, multiscale hybridisation, and aerospace structures. These nanoparticles can enhance osseointegration and bone development by mimicking the nanocomposition and nanoscale characteristics of bone tissue and enhance osteoconductive and osteoinductive capacities. Ceramic nanoparticles, however, have the potential to generate oxidative stress, which can result in irritation of the reticuloendothelial system, cytotoxicity to the heart, liver, and lungs, as well as toxicity to the cells that are attached. Additionally, oxidative stress, cell damage, and genotoxicity might result from the generation of free radicals by ceramic nanoparticles. Metal nanoparticles exhibit linear optical properties similar to molecular systems but arise from a different physical process. Semiconductor nanocrystals (NCs) are made from various compounds, such as silicon and germanium. Polyandry nanoparticles are particles approximately 10 and 10000 nanometers (nm) in size that can contain active substances. They have applications in vaccine delivery, gene therapy, and polymer nanoparticles (nanomedicine) for therapeutic applications.

Bioactive metabolites from endophytes of African club moss- Selaginella kraussiana (Kunze) A. Braun exhibit broad-spectrum pharmaceutical utilities

The search for potent natural compounds from plant and microbial sources is increasing logarithmically to combat various types of health issues of which multidrug-resistant microbes and problems related to oxidative stress are the prime ones. Novel secondary metabolites from endophytes have always been potent alternatives to contemporary antimicrobials and antioxidants. The present study shows that two potent endophytic fungal isolates Ascochyta medicaginicola SK16 and Phomopsis sp. SK5 synthesises non-proteinaceous, thermostable secondary metabolites with broad-spectrum antimicrobial, antioxidative, and cytotoxic activity. Bioassay-guided fractionation revealed that the Ethyl acetate (EA) extract of the cell-free culture extract (CFCE) of SK5 and SK16 constitutes ten and eleven secondary metabolites of which 2,4, -di tert butyl phenol, aziridine- 1,2-amino ethyl, actinobolin, bactobolin, azulene, menthyl acetate, phenol, p-[2-(methylamino)ethyl], and imidazole components were significant. SK16 exhibited strong antimicrobial activity against seventeen pathogens including Methicillin-resistant Staphylococcus aureus (MRSA), and C. albicans with a minimum microbicidal concentration of 100- 400 µg mL−1. These metabolites disrupt the microbial cell membranes causing lethal leakage of biomacromolecules- nucleic acid, protein, and potassium ions. Enzymes involved in the EMP pathway, TCA cycle, and gluconeogenesis were also blocked. Both the biofilm formation and transition of Candida cells from the yeast-to-hyphal form were inhibited. SK5 metabolites are potent radical scavengers with an IC50 of 34.25 ± 0.87 – 195.21 ± 5.73 µg mL−1 against DPPH, ABTS, FRAP, and H2O2 free radical generators and significantly increased antioxidant parameters in treated peritoneal macrophage cells of male Wistar rats. Also, SK5 metabolites were cytotoxic against breast (T47D), pancreatic (MIA Paca-2), lung (A549) and colon (HCT-116) cancer cells. The present findings suggest that metabolites from endophytes of African club moss hold potent pharmaceutical utilities.

Tetracycline degradation by dual-frequency ultrasound combined with peroxymonosulfate

Tetracycline has received a great deal of interest for the harmful effects of substance abuse on ecosystems and humanity. The effects of different processes on the degradation of tetracycline were compared, with dual-frequency ultrasound (DFUS) in combination with peroxymonosulfate (PMS) being the most effective for the tetracycline degradation. Free radical scavenging experiments showed that O2∙-,SO4∙- and •OH were the main reactive radicals in the degradation of tetracycline. According to the major intermediates of tetracycline degradation identified, three possible degradation pathways were proposed, which are of significance for translational studies of tetracycline degradation. Notably, these intermediates were found to be significantly less toxicity. The number of active bubbles in the degradation vessel was calculated using a semi-empirical formula, and a higher value of 1.44 × 108 L-1s−1 of bubbles was obtained when using dual-frequency ultrasound at 20 kHz (210 W/L) and 80 kHz (85.4 W/L). Therefore, compared to 20 kHz, although the yield of strong oxidizing substances from individual active bubbles decreased slightly, a significant increment of the number of active bubbles still resulted in a higher synergistic effect, and the combination of DFUS and PMS should be effective in promoting the generation of reactive free radicals and mass transfer processes within the degradation vessel, which provides a method for efficient removal of tetracycline from wastewater.

Preparation and performance evaluation of microencapsulated acid used for gel breaking of fracturing fluid in low-temperature reservoirs

In low-temperature reservoirs, the generation of free radicals by oxidizing breakers is challenging, and the alkaline fracturing fluid generally inhibits enzyme’s activity, making it difficult to break down the fracturing fluid. Previous studies have demonstrated that acids can consume borate ions and disrupt crosslinking nodes even at low temperatures, thereby efficiently breaking gels. Thus, microencapsulated oxalic acid (OA) was prepared via a coacervation method, using ethyl cellulose (EC) or acrylonitrile–butadiene–styrene (ABS) as shell materials with varying initiator viscosities and core–shell ratios. An optimal microcapsule MC[OA/ABS-2000-1:2] was determined based on the coating effect, productivity, encapsulation rate, and release performance. The test results of FT-IR and TGA together proved that the optimal microcapsule was composed of 24.4 and 74.8 % of OA and ABS, respectively. Scanning electron microscopy and laser particle size analysis were employed to characterize the optimal microcapsule with an average particle size of 402.8 μm, which exhibited a high degree of sphericity. Because of their porous shells, these microcapsules exhibited sustained slow-release characteristics. Evaluations conducted at temperatures of 30 and 50 ℃, simulating the tight sandstone reservoir conditions in the Ordos basin, revealed that delayed gel breaking could be achieved within approximately 2.5 h at low temperatures by adding only 0.25 % of the optimal microcapsule. Furthermore, increasing the temperature and dosage of microcapsules resulted in shorter breaking times. Additionally, a synergistic breaking effect was observed between the enzymes and the prepared microencapsulated acid. Thus, by optimizing the microcapsule dosage based on the reservoir temperature and fracturing construction pumping time, employing the two breakers together can achieve delayed and complete gel breaking at the desired time. In conclusion, the microencapsulated acid prepared in this study has significant potential as a gel breaker for fracturing fluids in low-temperature reservoirs.

Luteolin Alleviates Cadmium-Induced Kidney Injury by Inhibiting Oxidative DNA Damage and Repairing Autophagic Flux Blockade in Chickens.

Chickens are a major source of meat and eggs in human food and have significant economic value. Cadmium (Cd) is a common environmental pollutant that can contaminate feed and drinking water, leading to kidney injury in livestock and poultry, primarily by inducing the generation of free radicals. It is necessary to develop potential medicines to prevent and treat Cd-induced nephrotoxicity in poultry. Luteolin (Lut) is a natural flavonoid compound mainly extracted from peanut shells and has a variety of biological functions to defend against oxidative damage. In this study, we aimed to demonstrate whether Lut can alleviate kidney injury under Cd exposure and elucidate the underlying molecular mechanisms. Renal histopathology and cell morphology were observed. The indicators of renal function, oxidative stress, DNA damage and repair, NAD+ content, SIRT1 activity, and autophagy were analyzed. In vitro data showed that Cd exposure increased ROS levels and induced oxidative DNA damage and repair, as indicated by increased 8-OHdG content, increased γ-H2AX protein expression, and the over-activation of the DNA repair enzyme PARP-1. Cd exposure decreased NAD+ content and SIRT1 activity and increased LC3 II, ATG5, and particularly p62 protein expression. In addition, Cd-induced oxidative DNA damage resulted in PARP-1 over-activation, reduced SIRT1 activity, and autophagic flux blockade, as evidenced by reactive oxygen species scavenger NAC application. The inhibition of PARP-1 activation with the pharmacological inhibitor PJ34 restored NAD+ content and SIRT1 activity. The activation of SIRT1 with the pharmacological activator RSV reversed Cd-induced autophagic flux blockade and cell injury. In vivo data demonstrated that Cd treatment caused the microstructural disruption of renal tissues, reduced creatinine, and urea nitrogen clearance, raised MDA content, and decreased the activities or contents of antioxidants (GSH, T-SOD, CAT, and T-AOC). Cd treatment caused oxidative DNA damage and PARP-1 activation, decreased NAD+ content, decreased SIRT1 activity, and impaired autophagic flux. Notably, the dietary Lut supplement observably alleviated these alterations in chicken kidney tissues induced by Cd. In conclusion, the dietary Lut supplement alleviated Cd-induced chicken kidney injury through its potent antioxidant properties by relieving the oxidative DNA damage-activated PARP-1-mediated reduction in SIRT1 activity and repairing autophagic flux blockade.

Study of cabbage antioxidant system response on early infection stage of Xanthomonas campestris pv. campestris

Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) significantly affects the production of cabbage and other cruciferous vegetables. Plant antioxidant system plays an important role in pathogen invasion and is one of the main mechanisms underlying resistance to biological stress. Therefore, it is important to study the resistance mechanisms of the cabbage antioxidant system during the early stages of Xcc. In this study, 108 CFU/mL (OD600 = 0.1) Xcc race1 was inoculated on “zhonggan 11” cabbage using the spraying method. The effects of Xcc infection on the antioxidant system before and after Xcc inoculation (0, 1, 3, and 5 d) were studied by physiological indexes determination, transcriptome and metabolome analyses. We concluded that early Xcc infection can destroy the balance of the active oxygen metabolism system, increase the generation of free radicals, and decrease the scavenging ability, leading to membrane lipid peroxidation, resulting in the destruction of the biofilm system and metabolic disorders. In response to Xcc infection, cabbage clears a series of reactive oxygen species (ROS) produced during Xcc infection via various antioxidant pathways. The activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased after Xcc infection, and the ROS scavenging rate increased. The biosynthesis of non-obligate antioxidants, such as ascorbic acid (AsA) and glutathione (GSH), is also enhanced after Xcc infection. Moreover, the alkaloid and vitamin contents increased significantly after Xcc infection. We concluded that cabbage could resist Xcc invasion by maintaining the stability of the cell membrane system and improving the biosynthesis of antioxidant substances and enzymes after infection by Xcc. Our results provide theoretical basis and data support for subsequent research on the cruciferous vegetables resistance mechanism and breeding to Xcc.