Increased Antioxidant Enzyme Activities Research Articles

Polystyrene nanoplastics sequester the toxicity mitigating potential of probiotics by altering gut microbiota in grass carp (Ctenopharyngodon idella)

This study evaluated the role of probiotics in enhancing intestinal immunity and mitigating polystyrene nanoplastics (PS-NPs)-induced toxicity in grass carp (Ctenopharyngodon idella). Grass carp were fed probiotics (Bacillus subtilis, Bacillus velezensis, Lactobacillus reuteri, and Lactococcus lactis) for two weeks before being exposed to PS-NPs for five days. Probiotic pretreatment alleviated PS-NPs-induced intestinal damage, with Bacillus velezensis and Lactococcus lactis groups showing milder vacuolation and villus breakage than other groups. Probiotic-treated fish exhibited transient increases in antioxidant enzyme activities (CAT, SOD, MPO) and immune gene expression (IL-6, IL-8, IL-10, IL-1β, TNF-α, and IFN-γ2) shortly after exposure, followed by significant downregulation over time. Higher abundance of the gut dominant phylum Proteobacteria was observed in four probiotic groups exposed to PS-NPs than that in the blank control group. The Clostridium phylum showed a significant decrease in the abundance both in the LRS-PS100 and LLS-PS100 groups, while the abundance of the Thick-walled phylum increased. The Spearman correlation matrix revealed that specific gut microbiota, such as Serratia, Neisseria, and Lactococcus, were significantly associated with enzymatic activities and immune system related genes’ expressions. Probiotic pretreatment enhanced the intestinal immune response of grass carp. However, this enhanced immune response was insufficient to counteract the toxic effects of PS-NPs exposure, particularly in terms of oxidative stress levels and gut microbial diversity. This study offers new insights into the potential of probiotics to combat NPs pollution in aquaculture. It emphasizes the need for further research to explore various probiotic combinations. Future studies should also investigate optimal dosages and durations to effectively mitigate the biological toxicity of NPs pollution.

Lactobacillus reuteri TISTR 2736 alleviates type 2 diabetes in rats via the hepatic IRS1/PI3K/AKT signaling pathway by mitigating oxidative stress and inflammatory mediators.

This study investigated the beneficial effects of Lactobacillus reuteri TISTR 2736 on glucose homeostasis, carbohydrate metabolism, and the underlying mechanisms of its actions in type 2 diabetic (T2D) rats. A rat model of T2D was established by a combination of a high-fat diet and streptozotocin. The diabetic rats were treated daily with L. reuteri TISTR 2736 (2 × 108 CFU/day) for 30 days. Biochemical, histopathological, and molecular analyses were carried out to determine insulin signaling, carbohydrate metabolism, oxidative stress, and inflammation. The results demonstrated that treatment with L. reuteri TISTR 2736 significantly ameliorated fasting blood glucose and glucose intolerance, and improved insulin sensitivity indices in the diabetic rats. The hepatic histopathology was improved with L. reuteri TISTR 2736 treatment, which was correlated with a reduction of hepatic lipid profiles. L. reuteri TISTR 2736 significantly reduced glycogen content, fructose 1,6-bisphosphatase activity, and phosphoenolpyruvate carboxykinase 1 protein expression, and enhanced hexokinase activity in the diabetic liver. The downregulation of IRS1 and phosphorylated IRS1Ser307 and upregulation of PI3K and phosphorylated AKTSer473 proteins in the liver were found in the L. reuteri TISTR 2736-treated diabetic group. Furthermore, it was able to suppress oxidative stress and inflammation in the diabetic rats, as demonstrated by decreased malondialdehyde and protein levels of NF-κB, IL-6 and TNF-α, but increased antioxidant enzyme activities of superoxide dismutase, catalase, and glutathione peroxidase. By inhibiting oxidative and inflammatory stress, L. reuteri TISTR 2736 alleviated hyperglycemia and improved carbohydrate metabolism through activating IRS1/PI3K/AKT pathway in the T2D rats.

A soluble garlic polysaccharide supplement alleviates fatigue in mice

Garlic polysaccharide (GP) is an inulin-type fructan with potent antioxidant activity, whereas its health-promoting functions are not well explored. In the current study, we established a fatigue model by forcing mice to swim in a water tank for at least one hour every day. We measured changes in body weight, exhaustive swimming time, and biochemical indices related to fatigue in weight-bearing swimming mice fed low (1.25 g/kg-BW) and high doses (2.5 g/kg-BW) of GP by daily gavage for 7 weeks. The soluble GP was extracted from industrial garlic wastes using a patented method. The results indicate that GP improved symptoms by increasing the duration of exhaustive swimming, restoring blood biochemical markers (BUN and BLA), and increasing liver and muscle glycogen reserves in fatigued mice. GP also increased antioxidant enzyme activity (SOD, GSH-Px, and CAT) and restored ATPase activity by activating the AMPK/PGC-1α pathway. Additionally, GP modified the gut microbiota by increasing potentially beneficial bacteria and decreasing harmful bacteria. The increase in Bacteroidota and the decrease in Firmicutes phyla regulate the metabolism of short-chain fatty acids in the gut. In conclusion, GP may be effective in alleviating exercise-induced fatigue through multiple mechanisms and can be developed into health anti-fatigue supplements.

An integrated physiological indicator and transcriptomic analysis reveals the response of soybean buds to high-temperature stress.

Under global warming, high temperature (HT) has become a major meteorological factor affecting soybean production. To explore the candidate genes and regulatory mechanism of the soybean bud response to HT stress, previously identified as HT-tolerant ('Handou14'; HD14) and HT-sensitive ('Jiadou36'; JD36) were treated for 5 days in an artificial climate incubator either with HT (43°C (day)/ 33°C (night), 16h light/8h darkness) or the non-stress growth condition (25°C, 16h light/8h darkness) as the control at the bud stage were used as experimental materials in this study. After HT treatment, changes in physiological indicators including hypocotyl length, enzyme activity and hormone content were detected; at the same time, the cotyledons, hypocotyls, and main roots were collected for transcriptome sequencing analysis. Analyzing the mechanisms of HT stress response in the bud stage of HD14 and JD36 at physiological and transcription levels. Analysis of physiological indicator showed that the activities of superoxide dismutase (SOD) were significantly increased 47.4% and 41.2% in the cotyledon of HD14 and the main root of JD36, and the contents of peroxidase (POD) were significantly increased 61.5% and 125% in the hypocotyl of HD14 and JD36; the contents of malonaldehyde (MDA) were significantly increased 44.8% and 22.2% in the main root of HD14 and JD36 after HT treatment. The content of abscisic acid (ABA) were significantly increased 1.9 fold and 1.2 fold in the root of HD14 and JD36 in response to HT treatment, whereas the content of gibberellin (GA) were decreased 2.2 fold and 1.3 fold in the cotyledon and root, and increased 1.6 fold in the hypocotyl in HD14 (P < 0.05). Thus, higher SOD and POD activities, higher ABA content, and a smaller increase in MDA content may improve tolerance to HT stress. The HT-tolerant cultivar may have stronger GA signal transduction in the hypocotyl to combat the negative effects of HT. RNA-sequencing was performed to analyze the differential expression of genes in buds of the two cultivars under the HT treatment and control condition. In total, 3,633, 1,964, 9,934, and 3,036 differentially expressed genes (DEGs) were identified in the CH (control group of HD14) vs. TH (HT-treatment group of HD14), CJ (control group of JD36) vs. TJ (HT-treatment group of JD36), TJ vs. TH, and CJ vs. CH comparison groups, respectively. Bioinformatic analysis revealed that most DEGs were mainly involved in metabolic processes, catalytic activity, carbohydrate, energy transduction, and signaling pathways. The results of qRT-PCR validation (86.67%) and changes in physiological indicators were consistent with the RNA-sequencing data. Five DEGs were selected as candidate genes in the response to HT stress at the bud stage. In summary, soybean cells are protected from oxidative damage by an increase in antioxidant enzyme activities and accumulation of hormone content under HT stress. Concomitantly, changes in the expression of crucial genes and signal transmission processes are induced, thus initiating adaptive and protective mechanisms. This study provides a theoretical basis for clarification of the physiological and molecular mechanisms in the response to HT stress of soybean bud.

Protective effect of a novel furan hybrid chalcone against bisphenol A-induced craniofacial developmental toxicity in zebrafish embryos

Bisphenol A (BPA), a pervasive endocrine disruptor, is known to cause significant developmental toxicity, particularly affecting craniofacial structures through oxidative stress and apoptosis. A novel furan hybrid chalcone derivative, 3-(2-hydroxy-5-nitrophenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-one (DK04), specifically with a hydroxyl group for its antioxidant properties and a nitro group for enhanced electron-withdrawing ability, was evaluated for its potential to mitigate these toxic effects. Zebrafish embryos were exposed to BPA and co-treated with various concentrations of DK04. Our results demonstrated that DK04 significantly reduced reactive oxygen species (ROS) generation and lipid peroxidation, increased antioxidant enzyme activities (SOD and CAT), and restored the balance between pro-apoptotic (p53) and anti-apoptotic (bcl2) genes. Furthermore, DK04 treatment improved bone mineralization and chondrogenesis by reversing BPA-induced disruptions in osteogenic markers (runx2, sox9a, bmp6, and mmp13a). The locomotion impairments observed in BPA-exposed embryos were also ameliorated by DK04, indicating its potential neuroprotective effects. These findings suggest that DK04 offers a multifaceted approach to counteract BPA toxicity, making it a promising candidate for therapeutic intervention. This research underscores the importance of developing prophylactic compounds to safeguard health against environmental toxicants like BPA. Future studies should focus on long-term safety and efficacy in mammalian models and explore synergistic effects with other protective agents to broaden the applications of DK04 and contribute to public health benefits.

Microbiologically modified bioorganic fertilizer and metal-tolerant Bacillus sp. MN54 regulate the nutrient homeostasis and boost phytoextraction efficiency of mustard (Brassica juncea L.) in nickel-contaminated soil

Nickel (Ni) pollution in soil is a major environmental challenge to global food security necessitating its effective remediation. In this regard using plant growth promoting rhizobacteria (PGPR) and bioorganic fertilizers (BOF) to increase the effectiveness of Ni phytoextraction together with hyper-accumulator plants is an effective strategy. Thus, the aim of this study was to assess how BOF, alone or in combination with Bacillus sp. MN54 (herein after referred to as BS), promotes the growth and detoxifies Ni in Brassica juncea L. under both non-contaminated and Ni-contaminated soil conditions. The experimental design included both non-spiked and Ni-spiked soils (with two Ni concentrations: 50 and 100 mg kg−1), with the addition of BS and BOF at two different application rates (1% and 2%). Results showed that Ni negatively affected the growth attributes and yield of Brassica juncea but the integrated incorporation of BOF and BS significantly improved plant growth and physiological attributes. However, Ni stress increased antioxidant enzyme activities and triggered the production of reactive oxygen species in the plants. Likewise, the highest increases in Ni bioconcentration factor (19.9%, 72.83%, and 74.2%), Ni bioaccumulation concentration (30.6%, 327.4%, and 366.8%), and Ni translocation factor (22.2%, 82%, and 69%) were observed in soils supplemented with 2% BOF and BS under non-contaminated, 50 mg kg−1, and 100 mg kg−1 Ni-stressed conditions, respectively. The enhanced plant growth with BS and BOF under Ni stress suggested that both could efficiently promote Ni phytoextraction and simultaneously improve soil health in Ni-contaminated soil. This highlighted their potential as sustainable soil amendments for remediating Ni-contaminated soils, promoting resilient plant growth and supporting long-term ecosystem recovery.

The PHD transcription factor ThPHD5 regulates antioxidant enzyme activity to increase salt tolerance in Tamarix hispida

PHD proteins are an important class of transcription factors (TFs) that are widely distributed in eukaryotes and play crucial roles in many aspects of plant growth, development and response to stress. We identified a transcription factor, ThPHD5, from the PHD family in Tamarix hispida based on its potential involvement in abiotic stress response processes. In this study, the salt tolerance function of ThPHD5 from T. hispida was further characterized. The qRT-PCR results showed ThPHD5 expression was significantly induced by NaCl, PEG and ABA treatments. Transient transformation analysis revealed that ThPHD5 improved salt tolerance in T. hispida by increasing POD and SOD activity, decreasing the MDA, total ROS content and electrolyte leakage. To explore the salt tolerance mechanism of the ThPHD5 TF, its binding DNA motifs and potential downstream regulatory genes were analyzed. The results showed that ThPHD5 affect the expression of 7 antioxidant enzyme-related genes. The Yeast one-hybrid (Y1H) and Electrophoretic Mobility Shift Assay (EMSA) results indicated ThPHD5 could bind to ABRE, MYB and Dof cis-acting elements. ChIP-PCR further confirmed ThPHD5 exercise its regulatory function by directly binding motifs on the ThPOD16, ThSOD and ThSOD1 promoters. Taken together, these findings indicate the ThPHD5 TF improves salt tolerance in T. hispida by regulating the expression of antioxidant enzyme-related genes to increase antioxidant enzyme activity, enhance the ROS scavenge ability, reduce ROS accumulation and cellular damage.

Hepatoprotective effects of ethanolic extract of Corallocarpus epigaeus roots on nitrobenzene-induced liver injury in Wistar rats

ABSTRACT This study examined the potential of Corallocarpus epigaeus ethanolic root extract to combat free radicals using DPPH, FRAP, hydroxyl radical, hydrogen peroxide, and nitric oxide scavenging assays. Rats were initially exposed to a single oral dose of nitrobenzene (50 mg kg−1 body weight), followed by a 15-d oral regimen of the ethanolic root extract of C. epigaeus at 200 mg kg−1 body weight. The assessment of serum liver marker enzymes (AST, ALT, and ALP), lipid peroxidation levels, antioxidant enzyme activities, and histopathological examinations of liver tissues were carried out. The C. epigaeus ethanolic root extract demonstrated antioxidant properties and contained flavonoids, tannins, carotenoids, lycopene, and phenolic compounds. In Nitrobenzene-induced rats, elevated serum markers and increased liver lipid peroxidation were observed that were normalized by the extract. It also increased antioxidant enzyme activities, including superoxide dismutase, catalase, and glutathione peroxidase. Histopathological analysis confirmed the hepatoprotective effects of the extract.

Neuroprotective potential of Alpinia calcarata and HPLC analysis of stigmasterol against cisplatin-induced neuropathy in rat model

Cisplatin is a chemotherapeutic agent known for causing severe peripheral neuropathy as a side effect, impacting patients’ quality of life by damaging nerve tissues. This study aims to explore the neuroprotective effects of the ethanolic extract of Alpinia calcarata Roscoe rhizome (EEACR) and stigmasterol identified by high-performance liquid chromatography (HPLC) in a rat model of cisplatin-induced neuropathy. Male Wistar rats were divided into control, cisplatin-induced neuropathic, and two intervention groups receiving different concentrations of EEACR (250 and 500 mg/kg). Neuropathy was induced with cisplatin administered intraperitoneally at a dose of 2 mg/kg per week for five weeks. The intervention groups were treated orally with EEACR daily during the induction period. Treatment with EEACR showed a significant attenuation of neurotoxicity as evidenced by behavioural improvements in mechanical allodynia, thermal hyperalgesia, and cold allodynia. HPLC analysis confirmed the presence of stigmasterol in EEACR, which may contribute to its therapeutic effects. Biochemical assessments revealed a significant decrease in oxidative stress markers and an increase in antioxidant enzyme activities, including superoxide dismutase, catalase, and glutathione peroxidase, in the nervous tissues of EEACR-treated rats. Histopathological examination indicated a reduction in nerve damage and enhanced preservation of myelin and axonal structures in the treatment groups. The findings from this study suggest that EEACR, enriched with stigmasterol, offers promising neuroprotective effects against cisplatin-induced neuropathy in rats.

The protective effect of Auricularia auricula polysaccharides on cyclophosphamide-induced immunosuppression and intestinal injury: A fecal microbiota transplantation study

Auricularia auricula polysaccharides (AHP) have potential immunomodulatory activities. However, the relationship between polysaccharides, intestinal microbiota, and immune activity remains unclear. Therefore, to explore this relationship, we performed immunosuppressive donor, fecal microbiota transplantation (FMT), and pseudo-sterile mouse validation experiments. Our results showed that AHP enhanced immunomodulatory activity, as evidenced by the alleviation of cyclophosphamide (Cy)-induced body weight loss, spleen and thymus atrophy, and splenic and colonic lesions. Additionally, AHP effectively regulated antioxidant enzyme activities (SOD, T-AOC, CAT, GSH-Px), lipid peroxidation product content (MDA), levels of immune factors (TNF-α, IFN-γ, IL-2, IL-4, IL-6), immunoglobulins (sIgA), and the expression of tight junction proteins (Muc2, ZO-1, Occuldin, and Claudin-1) in the colon of immunosuppressed mice. FMT results demonstrated that FAHP displayed superior immunomodulatory ability and could further affect the abundance of Dehydroepiandrosterone, Prostaglandin E2, Cholesterol and Pregnenolone by increasing the abundance of unclassified_Muribaculaceae, Desulfovibrio, Alloprevotella, and unclassified_Oscillospiraceae and decreasing that of Staphylococcus, Bacteroides, and Corynebacterium. Pseudo-sterilization experiments showed that AHP was unable to increase antioxidant enzyme activity, reduce lipid peroxidation content, or promote the release of immune factors. In brief, AHP did not alleviate Cy-induced immunosuppression after microbiota elimination. In summary, AHP exerted a protective effect against Cy-induced immunosuppression and intestinal damage by modulating intestinal microbiota and its metabolites. These findings provide new insights into the mechanisms by which AHP, as a functional food or drug, promotes immune response regulation and maintains intestinal health.

Eukaryotic expression of chitinase from dark sleeper (Odontobutis potamophila) and its effects on growth and immunity

Chitinase, an enzyme that hydrolyzes β-1,4-glycosidic bonds to degrade chitin, is essential for the digestion of chitin in fish. In this study, the chitinase OpCht from Odontobutis potamophila was expressed in Pichia pastoris, and its enzymatic properties and functional effects were evaluated. The findings revealed that OpCht exhibited optimal activity at pH 6.0 and 50 °C, with stability in the pH range of 4–8 and temperatures from 4 to 40 °C. K+, Na+, Ca2+, Mg2+, Mn2+, Hg2+, and Al3+ showed varying degrees of activation on the enzyme. At the end of the 8-week trial, the addition of OpCht significantly increased the height of intestinal villi and the thickness of the muscular layer, leading to significantly weight in the treated groups. The alleviation of intestinal inflammation also resulted in an increased survival rate (SR) of O. potamophila. High concentration treatment groups (2, 4 μg/g) showed significantly elevated digestive enzyme activities, as well as increased antioxidant enzyme activities and immune parameters. These results demonstrate that the P. pastoris expression system has successfully produced the chitinase OpCht from O. potamophila, and the addition of a certain concentration of OpCht can promote fish growth and enhance immune functions, offering a promising enzyme preparation for the aquaculture industry.

Schistosomicidal Effects of Moringa oleifera Seed Oil Extract on Schistosoma mansoni-Infected Mice.

Schistosomiasis causes severe hepatic fibrosis, making it a global health issue. Moringa oleifera seed oil extract, which had antiparasitic, anti-inflammatory and antioxidant effects, was investigated as an alternative treatment. The 50 mice were divided into control, infected, praziquantel-treated, M. oleifera seed oil extract-treated and combined treatment groups. These treatments were examined for their effects on egg granulomas, hepatic enzymes, total protein, albumin, antioxidant enzymes and pro-inflammatory cytokines. M. oleifera seed oil and/or PZQ significantly reduced egg numbers, granuloma size and liver histopathology. M. oleifera seed oil reduced hepatic enzyme activity, increased total protein and albumin, and increased antioxidant enzyme activity while decreasing malondialdehyde. M. oleifera seed oil reduced the levels of pro-inflammatory cytokines. M. oleifera seed oil may treat schistosomiasis instead of PZQ due to its antifibrotic, immunomodulatory and schistosomicidal properties.

Microbes mediated alleviation of chromium (Cr VI) stress for improved phytoextraction in fodder maize (Zea mays L.) cultivar

This study investigates the potential of chromium (VI) resistant bacterial isolates to alleviate heavy metal stress in fodder maize plants and enhance phytoremediation. Twenty-one bacterial strains were isolated from contaminated water, with five strains; Bacillus thuringiensis (BHR1), Bacillus cereus (BHR2), Enterobacter cloacae (BHR4), Bacillus pumilus (BHR5), and Bacillus altitudinis (BHR6) selected based on their significant plant-growth promoting (PGP) traits and heavy metal tolerance. Under chromium (Cr VI) stress, the BHR1 strain significantly improved seed germination, seedling length and vigor index of fodder maize variety (J 1007) especially at 150 mg/L Cr (VI), where these parameters increased by 3.75, 3.23 and 6.44 folds, respectively. After 60 days, BHR1 also enhanced shoot and root lengths by 4.91 and 4.06 folds, respectively and increase fresh and dry biomass, especially at higher Cr (VI) concentrations. Photosynthetic pigments, chlorophyll a and b, were also elevated by 3.04 and 2.26 times, respectively. Additionally, BHR1 reduced oxidative stress markers, including proline and malondialdehyde (MDA), and decreased electrolyte leakage, thus improving membrane stability. The strain further increased antioxidant enzyme activities and chromium uptake in root and shoot tissues, enhancing the translocation factor by 95%. This suggests that BHR1 can significantly promote fodder maize growth and accelerate chromium removal from contaminated soil, offering valuable insights into plant-microbe interactions under Cr (VI) stress.

Brassinosteroid improves light stress tolerance in tomato (Lycopersicon esculentum) by regulating redox status, photosynthesis and photosystem II.

Plants often experience variations in light intensity, referred to as light stress, that negatively impact important aspects of plant growth and development, including photosynthesis and antioxidant system. The photosynthetic machinery is susceptible to these disturbances, especially photosystem II and its reaction centers. We aimed to evaluate the role of brassinosteriod in plants under both high and low light conditions by examining various physiological parameters such as photosynthetic efficiency, pigment levels, and enzymatic activity of various antioxidant enzymes in one month old tomato plants. We investigated various chlorophyll fluorescence parameters under low light (LL) and high light (HL) conditions and the associated gene expression related to photosynthesis, including plastocyanin, ferredoxin, and photosystem II oxygen-evolving enhancer protein 3 (PsbQ). Our results indicate that exogenous brassinosteroid application considerably increased tolerance to both high and low light stress in 4-week-old tomato as treated plants displayed enhanced photosynthesis, reduced oxidative damage, and increased antioxidant enzyme activity in comparison to control plants. Furthermore, brassinosteroid treatment enhanced the expression of genes associated with antioxidant pathways, which significantly contributed to the recovery of chlorophyll fluorescence parameters crucial for plant growth and development. Our results provide valuable insights into how brassinosteroid reduces light-induced stress in tomato plants.

Plant enzymatic activity as an indicator of nano-TiO2 exposure in rice ecosystems

The widespread use of nano-titanium dioxide (nano-TiO2) has raised concerns about its environmental impact, particularly in soil-plant systems. This study investigates the effects of nano-TiO2 on rice (Oryza sativa cv. PB1121) growth and enzymatic activities, compared to bulk TiO2, through a pot culture experiment. Eight doses of Ti were applied: six as soil treatments (0, 2.5, 5, 10, 25, and 50 mg Ti kg⁻¹) and two as foliar treatments (0.05 % and 0.1 %). Results showed that grain yield peaked at 25 mg Ti kg⁻¹ soil for both nano and bulk TiO2, while a 0.05 % foliar spray outperformed by 0.1 %. Titanium accumulated mostly in roots, followed by straw and grains. Nano-TiO2 significantly increased antioxidant enzyme activities—catalase (CAT), superoxide dismutase (SOD), guaiacol peroxidase, and ascorbate peroxidase (APX)—and lipid peroxidation (measured as malondialdehyde) in rice roots and shoots, indicating oxidative stress. The findings suggest that plant enzymatic activity serves as an early indicator of nano-TiO2 exposure, making it a valuable biomarker for environmental monitoring. However, higher Ti doses may inhibit plant growth depending on Ti source and concentration. Further studies should examine the effects of nano-TiO2 of different sizes, shapes, and charges on various crops and soil types to validate these results and assess the broader implications for agricultural and environmental health. This research highlights the dual potential of nano-TiO2 as both a growth enhancer and a stress-inducing agent, emphasizing the need for careful management in agricultural applications.

Augmenting Rice Defenses: Exogenous Calcium Elevates GABA Levels Against WBPH Infestation.

This study investigates the impact of exogenous calcium and gamma-aminobutyric acid (GABA) supplementation on rice growth and stress tolerance under white-backed planthopper (WBPH) infestation. We evaluated several phenotypic traits, including shoot/root length, leaf width, tiller number, panicle length, and relative water content, alongside physiological markers such as oxidative stress indicators, antioxidant enzymes activities, hormonal levels, and amino acids biosynthesis. Our results indicate that WBPH stress significantly reduces growth parameters but calcium and GABA supplementation markedly enhance shoot length (by 26% and 36%) and root length (by 38% and 64%), respectively, compared to WBPH-infested plants. Both supplementations also reduced oxidative stress, as evidenced by decreased H2O2 and O2•- levels and a lower electrolyte leakage. Notably, calcium and GABA treatments increased antioxidant enzyme activities, with GABA boosting catalase (CAT) activity by 800%, peroxidase (POD) by 144%, and superoxide dismutase (SOD) by 62% under WBPH stress. Additionally, calcium and GABA enhanced the accumulation of stress hormones (abscisic acid ABA) and salicylic acid (SA) and promoted stomatal closure, contributing to improved water conservation. This study reveals that calcium regulates the GABA shunt pathway, significantly increasing GABA and succinate levels in both root and shoot. Furthermore, calcium and GABA supplementation enhance the biosynthesis of key amino acids and improve ion homeostasis, particularly elevating calcium (Ca), iron (Fe), and magnesium (Mg) levels under WBPH stress. Overall, this study highlights the potential of exogenous calcium and GABA as effective strategies for enhancing rice plant tolerance to WBPH infestation by modulating various physiological and biochemical mechanisms. Further research is warranted to fully elucidate the underlying mechanisms of action.

Nitric Oxide-Dependent Regulation of Oxygen-Related Processes in a Rat Model of Lead Neurotoxicity: Influence of the Hypoxia Resistance Factor

Background/Aims: Lead exposure is known to induce oxidative stress and neurotoxicity. Nitric oxide (NO) plays an important role in modulating oxidative stress, with L-arginine as a precursor of NO and Nω-nitro-L-arginine (L-NNA) as an inhibitor of NO synthase, an enzyme that catalyses the production of nitric oxide (NO) from L-arginine. Methods: This study investigated the differential effects of L-arginine and L-NNA on markers of oxidative stress and biochemical changes in brain tissue from rats with different levels of resistance to hypoxia exposed to lead nitrate. Rats with either low or high resistance to hypoxia were exposed to lead nitrate (oral 3.6 mg lead nitrate/kg b.w. per day for 30 days) and treated with L-arginine (600 mg/kg b.w., i.p., 30 min before and after exposure to lead nitrate) or L-NNA (35 mg/kg b.w., i.p., 30 min before and after exposure to lead nitrate). Brain tissue samples were analysed for lipid peroxidation, oxidative modification of proteins, and activity of antioxidant enzymes, including superoxide dismutase, catalase, glutathione reductase, and peroxidase, and total antioxidant status (TAS). We also examined the biomarkers of biochemical pathways involving the activity of alanine and aspartate aminotransferases, succinate dehydrogenase (SDH), and α-ketoglutarate dehydrogenase (KGDH). In addition, the trend observed was supported by assessments of the acetylcholine levels and acetylcholinesterase activity (ACh-AChE system) in brain tissue. Results: In rats with low resistance to hypoxia, the L-arginine treatment significantly reduced lipid peroxidation and oxidative protein modification but increased antioxidant enzyme activity, suggesting a protective effect against lead-induced oxidative stress. Conversely, in rats with high resistance to hypoxia, L-NNA had a protective effect, reducing lead-induced oxidative damage and decreasing lipid peroxidation, whereas L-arginine exacerbated oxidative stress and impaired antioxidant defences. These findings were supported by corresponding changes in the acetylcholine-acetylcholinesterase system, reflecting the observed patterns of lead-induced oxidative stress and neurotoxicity. The study shows that L-arginine exerts a protective effect by reducing lead-induced oxidative damage via an improvement in TAS. Our study shows that lead nitrate exposure significantly increases ala-nine and aspartate aminotransferase activity in brain tissue, with L-arginine exacerbating and L-NNA reversing this effect. The lead nitrate exposure also affected the activities of SDH and KGDH, which are important for cellular energy production and hypoxia resistance, with L-arginine altering SDH activity depending on the level of resistance and L-NNA enhancing both SDH and KGDH activities. These trends were further validated by alterations in the ACh-AChE system, highlighting the differential role of NO-dependent mechanisms in modulating lead-induced neurotoxicity based on hypoxia resistance. Conclusion: These findings suggest potential targeted therapeutic strategies based on the oxidative stress profile and highlight the potential of nitric oxide system modulators in counteracting lead-induced biochemical alterations and the dynamics of the ACh-AChE system depending on the individual physiological reactivity of organisms.

The Effects of Dietary Orange Peel Fragments Enriched with Zinc and Vitamins C and E on the Antioxidant and Immune Responses of Nile Tilapia under Stress Conditions.

This study aimed to evaluate the effect of dietary orange peel fragments (OPFs) enriched with vitamins C (C) and E (E), as well as zinc (Zn) on the growth performance, hematological profile, immunological parameters, antioxidant capacity, and fillet lipid peroxidation of Nile tilapia subjected to heat/dissolved oxygen-induced stress (HDOIS), transport-induced stress (TIS), and Aeromonas hydrophila infection (BC). A group of 500 male Nile tilapia (2.7 ± 0.03 g) was randomly distributed in twenty-five 250 L aquaria (20 fish/aquarium) and fed diets containing OPFs (6 g kg-1), OPFs/C (6 g kg-1/1.8 g kg-1), OPFs/E (6 g kg-1/0.4 g kg-1), OPFs/Zn (6 g kg-1/0.21 g kg-1), or OPFs/C/E/Zn (6 g kg-1/1.8 g kg-1/0.4 g kg-1/0.21 g kg-1) for 100 days. The diets were formulated to contain 30% crude protein and 17 MJ kg-1 gross energy. After the feeding period, three groups of fish were independently subjected to a different type of stress: HDOIS (34 °C) for two days; TIS for four hours, or BC for 15 days. The hematological profile, antioxidant capacity, and fillet lipid peroxidation were determined before and after all the stress treatments, along with immunological parameters, which were investigated only for the fish subjected to bacterial infection. In summary, the results showed that growth was not affected by the OPFs, nor by the OPFs enriched with C, E, and Zn; bacterial infection determined anemia for the fish fed any of the experimental diets; the OPFs did not prevent lipid peroxidation under TIS and BC; on the other hand, when enriched with C/E/Zn, lipid peroxidation decreased under HDOIS and TIS. In conclusion, the OPFs enriched with C/E/Zn showed a synergistic effect that promoted an increase in antioxidant enzyme activity, a decrease in lipid peroxidation, and the maintenance of the hematological profile under HDOIS and TIS, but they were not able to maintain the health status under BC.

Toxicological effects and defense mechanisms induced by beta-cypermethrin in Drosophila melanogaster

Widespread use of the pyrethroid insecticide beta-cypermethrin (beta-CYP) has led to adverse effects on nontarget populations within agroecosystems. Despite the efficacy of beta-CYP in pest control, its toxicological and defense mechanisms remain incompletely understood. In the present study, we explored the toxicological effects, antioxidant mechanisms and immune response against beta-CYP using Drosophila melanogaster, a well-established model organism for the study of insect biology, to represent the broader class of nontarget organisms. We exposed Drosophila larvae to 0.667 μg/mL beta-CYP and revealed that delayed development and caused intestinal epithelial damage in larvae. To gain insights into the molecular underpinnings of these effects, RNA sequencing analysis and quantitative polymerase chain reaction validation were performed. These analyses revealed that the messenger RNA levels of glutathione S-transferase were increased, third instar larvae exhibited an increase in reactive oxygen species content and a corresponding increase in antioxidant enzyme activity in response to beta-CYP exposure, indicating an upregulated response to oxidative stress. Beta-CYP also activated Hippo pathway to resist apoptosis and promote cell proliferation. Moreover, beta-CYP induced melanization and Toll immune pathways involved in immune response in Drosophila larvae, specifically the Toll pathway gene Drs. This activation suggests that Drosophila increases antioxidant defenses and promotes mitosis in damaged tissues as compensatory mechanisms to mitigate the cytotoxic effects of beta-CYP. These findings provide new insight into the mechanisms of beta-CYP–induced toxicity and the defense mechanisms in insects; they may also inform strategies for the sustainable use of insecticides and the development of mitigation measures to protect nontarget species in agroecosystems.

Combined impact of antibiotics and Cr(VI) on antibiotic resistance, ARGs, and growth of Bacillussp. SH-1: A functionl analysis from gene to protease

The simultaneous selection of antibiotic resistance genes (ARGs) induced by heavy metals and antibiotics has emerged as a growing environmental problem. This study investigated the combined effects of chromium (Cr(VI)) and antibiotics on the ARGs of Bacillus cereus SH-1. As Cr(VI) concentration increased, it triggered reactive oxygen species oxidative stress in SH-1, increased antioxidant enzyme activity, enhanced plasmid conjugative transfer, and reduced the efficiency of Cr(VI) removal by SH-1. Antibiotic resistance varied with increasing tetracycline and amoxicillin minimum inhibitory concentrations (MICs), whereas azithromycin and chloramphenicol MICs decreased with Cr(VI) induction. The overexpression of eight genes of the HAE-1 family of efflux pumps was detected using metagenomics and proteomics. Co-contamination with Cr(VI) and antibiotics has led to the emergence and spread of antibiotic-resistant bacteria. Therefore, resistance gene contamination resulting from Cr(VI)-polluted environments cannot be overlooked.