Methionine oxidation in bacteria: A reversible post-translational modification.

Methionine is a sulfur-containing residue found in most proteins which are particularly susceptible to oxidation. Although methionine oxidation causes protein damage, it can in some cases activate protein function. Enzymatic systems reducing oxidized methionine have evolved in most bacterial species and methionine oxidation proves to be a reversible post-translational modification regulating protein activity. In this review, we inspect recent examples of methionine oxidation provoking protein loss and gain of function. We further speculate on the role of methionine oxidation as a multilayer endogenous antioxidant system and consider its potential consequences for bacterial virulence.

Differential responses of two fenugreek (Trigonella foenum-graecum L.) landraces pretreated with melatonin to prolonged drought stress and subsequent recovery.

BACKGROUND: Drought impairs growth, disturbs photosynthesis, and induces senescence in plants, which results in crop productivity reduction and ultimately jeopardizes human food security. The objective of this study was to determine major parameters associated with drought tolerance and recovery ability of fenugreek (Trigonella foenum-graecum L.), by examining differential biochemical and phenological responses and underlying enzyme activities as well as melatonin roles during drought stress and re-watering for two contrasting landraces. Moreover, the relative expression of three key genes involved in the biosynthesis pathway of diosgenin, including SQS, CAS, and BG, was investigated. RESULTS: Depending on the conditions, drought stress enhanced the activity of antioxidant enzymes and the osmoregulating compounds, non-enzymatic antioxidants, hydrogen peroxide content, and lipid peroxidation levels in most cases. Severe drought stress accelerated flowering time in Shushtar landrace (SHR) but had no significant effects on Varamin (VR). Pretreatment with melatonin delayed flowering time in SHR and caused high drought resistance in this landrace. Furthermore, melatonin significantly enhanced drought adaptability in VR by improving plant recovery ability. DISCUSSION: Based on our results plants' responses to drought stress and melatonin pretreatment were completely landrace-specific. Drought stress caused an increase in the relative expression of CAS gene and ultimately the accumulation of steroidal saponins in SHR. Melatonin compensated for the decrease in biomass production due to drought stress and finally increased steroidal saponins performance in SHR. Our study showed that melatonin can improve drought stress and recovery in fenugreek, but different factors such as genotype, melatonin concentration, and plant age should be considered.

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.

Physiological and antioxidant responses of synthetic hexaploid wheat germplasm under drought.

BACKGROUND: As a result of the world population and climate change impact increases (especially in arid environments), there is a critical need for high-yield, drought-tolerant wheat. Synthetic hexaploid wheat derived lines (SHW-DL), were created artificially by crossing different durum wheat cultivars (AABB) with accessions of Aegilops tauschii (DD), a beneficial source of new genes for common bread wheat (Triticum aestivum L). Here, we studied the response of a panel of 91 SHW-DL for drought tolerance based on physiological, antioxidant enzyme activities, and drought tolerance indices. RESULTS: A wide range of variation and high values of heritability observed for grain yield, physiological and antioxidant traits indicating that the SHW-DL panel constitutes a valuable gene source for drought tolerance improvement of wheat. Despite decreases in grain yield (YLD), leaf area index (LAI), and relative water content (RWC) an increase in the content of malondialdehyde (MDA) was observed. Moreover, drought streass increased the antioxidant enzyme activities of ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD), and also photosynthetic pigments, proline (Pro), and MDA content. With higher values of grain yield, physiological and biochemical traits such as photosynthetic pigments, and RWC, and lower content of MDA, and peroxidase (H2O2) activity, SHW-DL performed better compared to common wheat lines under water stress conditions. CONCLUSIONS: Different responses to water stress within the germplasm and between synthetic and common wheat suggest that selection for adaptive and suitable genotypes is possible for drought tolerance in synthetic wheat germplasm. Genotypes 54, 98, 102, 105, 122, 124, 143, 159, 196, and 198 were identified to be directly used in breeding programs or indirectly by crossing them with other wheat germplasm collections.

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

BACKGROUND: 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. RESULTS: 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 1,111,628,179 bp). 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. CONCLUSIONS: 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.

Adequate water supply enhances seedling growth and metabolism in Festuca kryloviana: insights from physiological and transcriptomic analys.

BACKGROUND: Festuca kryloviana is a significant native grass species in the Qinghai Lake region, and its low emergence rate is a primary factor limiting the successful establishment of cultivated grasslands. The region's arid and low-rainfall climate characteristics result in reduced soil moisture content at the surface. Despite the recognized impact of water availability on plant growth, the specific role of moisture in seedling development remains not fully elucidated. This study aims to investigate the germination rate and seedling growth velocity of F. kryloviana seeds under varying moisture conditions, and to integrate physiological and transcriptomic analyses of seedlings under these conditions to reveal the mechanisms by which water influences seedling development. RESULTS: The emergence rate of F. kryloviana seedlings exhibited an initial increase followed by a decrease with increasing moisture content. The highest emergence rate, reaching 75%, was observed under 20% soil moisture conditions. By the eighth day of the experiment, the lengths of the plumules and radicles under the optimal emergence rate (full water, FW) were 21.82% and 10.87% longer, respectively, than those under closely matching the soil moisture content during the background survey (stress water, SW). The differential development of seedlings under varying moisture regimes is attributed to sugar metabolism within the seeds and the accumulation of abscisic acid (ABA). At FW conditions, enhanced sugar metabolism, which generates more energy for seedling development, is facilitated by higher activities of α-amylase, sucrose synthase, and trehalose-6-phosphate synthase compared to SW conditions. This is reflected at the transcriptomic level with upregulated expression of the α-amylase (AMY2) gene and trehalose-6-phosphate synthase (TPS6), while genes associated with ABA signaling and transduction are downregulated. Additionally, under FW conditions, the expression of genes related to the chloroplast thylakoid photosystems, such as photosystem II (PSII) and photosystem I (PSI), is upregulated, enhancing the seedlings' light-capturing ability and photosynthetic efficiency, thereby improving their autotrophic capacity. Furthermore, FW treatment enhances the expression of the non-enzymatic antioxidant system, promoting metabolism within the seeds. In contrast, SW treatment increases the activity of the enzymatic antioxidant system, including peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), to cope with water stress. CONCLUSIONS: Our experiment systematically evaluated the impact of moisture conditions on the growth and development of F. kryloviana seedlings. Physiological and transcriptomic data collectively indicate that adequate water (20%) supply enhances seedling growth and development by reducing ABA levels and increasing α-amylase activity within seeds, thereby boosting sugar metabolism and promoting the growth of seedling, which in turn leads to an improved emergence rate. Considering water management in future cultivation practices may be a crucial strategy for enhancing the successful establishment of F. kryloviana in grassland ecosystems.

Exogenously applied silver nanoparticles (AgNPs) differentially affect bacterial blight disease control in twenty-seven wheat cultivars.

The bacterial blight of wheat is an important global disease causing a significant decline in crop yield. Nanotechnology offers a potential solution for managing plant diseases. Therefore, this research aimed to investigate the effectiveness of silver nanoparticles (AgNPs) in controlling bacterial blight in 27 locally grown wheat cultivars. The study examined the impact of AgNPs at three distinct time points: 1, 3, and 5 days after the onset of the disease. Biochemical assay revealed that one day after applying the disease stress, the Inia cultivar had the highest amount of soluble protein (55.60 µg.g-1FW) content in the treatment without AgNPs. The Azadi cultivar, without AgNPs treatment, had the lowest amount of soluble protein content (15.71 µg.g-1FW). The Tabasi cultivar had the highest activity of the superoxide dismutase (SOD) (61.62 mM.g-1FW) with the combination treatment of AgNPs. On the other hand, the Karchia cultivar had the lowest SOD activity (0.6 mM.g-1FW) in the treatment of disease without AgNPs. Furthermore, three days after the application of stress, the Mahdavi cultivar had the highest amount of soluble protein content (54.16 µg.g-1FW) in the treatment of disease without AgNPs. The Niknejad cultivar had the highest activity of the SOD (74.15 mM.g-1FW) with the combined treatment of the disease without AgNPs. The Kavir cultivar had the lowest SOD activity (1.95 mM.g-1FW) and the lowest peroxidase (POX) activity (0.241 mM g-1FW min-1) in the treatment of the disease with AgNPs. Five days after exposure to stress, the Mahooti cultivar had the highest SOD activity (88.12 mM.g-1FW) with the combined treatment of the disease with AgNPs, and the Karchia cultivar had the lowest SOD activity (2.39 mM.g-1FW) in the treatment of the disease with AgNPs. Further, the results indicated that exposure to AgNPs could improve the antioxidant properties of wheat seeds in blight-infected and disease-free conditions in some cultivars.

The application potential of mepiquat chloride in soybean: improvement of yield characteristics and drought resistance.

BACKGROUND: Drought can result in yield losses, the application of plant growth regulators is an effective measure to improve drought resistance and yield. The objective of the study was to explore the application potential of mepiquat chloride (MC) in regulating soybean yield and drought resistance. METHODS: In this study, a three-year field experiment was designed and combined with drought experiments to measure the yield of popularized varieties during 2021-2022 and drought-resistant and drought-sensitive varieties were selected, and planted in the field in 2023. RESULTS: MC increased the yield of HN84 and HN87 for two consecutive years from 2021 to 2022 and improved their physiological characteristics under field conditions. Under M200 treatment, the yield of HN84 increased by 6.93% and 9.46%, and HN87 increased by 11.11% and 15.72%. Different concentrations of MC have different effects on soybeans. The maximum increase of SOD, POD and proline in HN84 under M400 treatment reached 71.92%, 63.26% and 71.54%, respectively; the maximum increase of SOD, POD and proline in HN87 under M200 treatment reached 21.96%, 93.49% and 40.45%, respectively. In 2023, the foliar application of MC improved the physiological characteristics of HN44 and HN65 under drought-stress conditions. On the eighth day of drought treatment, compared to the drought treatment, the leaf and root dry weight of HN44 under M100 treatment increased by 17.91% and 32.76%, respectively; the dry weight of leaves and roots of HN65 increased by 20.74% and 29.29% under M200 treatment, respectively. MC also reduced malondialdehyde (MDA) content, decreased antioxidant enzyme activity and proline content. In addition, different concentrations of MC increased the chlorophyll fluorescence parameters (Fs, Fv/Fm, YII, and SPAD). In the field, the plant height of the two varieties decreased significantly, the yield increased, the number of two-grain and three-grain pods increased, and the stem length at the bottom and middle decreased with MC induction. CONCLUSIONS: The application of 100-200 mg/L MC effectively improved drought resistance and increased yield. This study provided support for the rational application of MC in soybean production.

Phosphate solubilizing Aspergillus Niger PH1 ameliorates growth and alleviates lead stress in maize through improved photosynthetic and antioxidant response.

Among the several threats to humanity by anthropogenic activities, contamination of the environment by heavy metals is of great concern. Upon entry into the food chain, these metals cause serious hazards to plants and other organisms including humans. Use of microbes for bioremediation of the soil and stress mitigation in plants are among the preferred strategies to provide an efficient, cost-effective, eco-friendly solution of the problem. The current investigation is an attempt in this direction where fungal strain PH1 was isolated from the rhizosphere of Parthenium hysterophorus which was identified as Aspergillus niger by sequence homology of the ITS 1 and ITS 4 regions of the rRNA. The strain was tested for its effect on growth and biochemical parameters as reflection of its potential to mitigate Pb stress in Zea mays exposed to 100, 200 and 500 µg of Pb/g of soil. In the initial screening, it was revealed that the strain has the ability to tolerate lead stress, solubilize insoluble phosphate and produce plant growth promoting hormones (IAA and SA) and other metabolites like phenolics, flavonoids, sugar, protein and lipids. Under 500 µg of Pb/g of soil, Z. mays exhibited significant growth retardation with a reduction of 31% in root length, 30.5% in shoot length, 57.5% in fresh weight and 45.2% in dry weight as compared to control plants. Inoculation of A. niger to Pb treated plants not only restored root and shoot length, rather promoted it to a level significantly higher than the control plants. Association of the strain modulated the physio-hormonal attributes of maize plants that resulted in their better growth which indicated a state of low stress. Additionally, the strain boosted the antioxidant defence system of the maize there by causing a significant reduction in the ascorbic acid peroxidase (1.5%), catalase (19%) and 1,1-diphenyl-2 picrylhydrazyl (DPPH) radical scavenging activity (33.3%), indicating a lower stress condition as compared to their non-inoculated stressed plants. Based on current evidence, this strain can potentially be used as a biofertilizer for Pb-contaminated sites where it will improve overall plant health with the hope of achieving better biological and agricultural yields.

Silicon regulates phosphate deficiency through involvement of auxin and nitric oxide in barley roots.

MAIN CONCLUSION: Silicon application mitigates phosphate deficiency in barley through an interplay with auxin and nitric oxide, enhancing growth, photosynthesis, and redox balance, highlighting the potential of silicon as a fertilizer for overcoming nutritional stresses. Silicon (Si) is reported to attenuate nutritional stresses in plants, but studies on the effect of Si application to plants grown under phosphate (Pi) deficiency are still very scarce, especially in barley. Therefore, the present work was undertaken to investigate the potential role of Si in mitigating the adverse impacts of Pi deficiency in barley Hordeum vulgare L. (var. BH902). Further, the involvement of two key regulatory signaling molecules--auxin and nitric oxide (NO)--in Si-induced tolerance against Pi deficiency in barley was tested. Morphological attributes, photosynthetic parameters, oxidative stress markers (O2·-, H2O2, and MDA), antioxidant system (enzymatic--APX, CAT, SOD, GR, DHAR, MDHAR as well as non-enzymatic--AsA and GSH), NO content, and proline metabolism were the key traits that were assessed under different treatments. The P deficiency distinctly declined growth of barley seedlings, which was due to enhancement in oxidative stress leading to inhibition of photosynthesis. These results were also in parallel with an enhancement in antioxidant activity, particularly SOD and CAT, and endogenous proline level and its biosynthetic enzyme (P5CS). The addition of Si exhibited beneficial effects on barley plants grown in Pi-deficient medium as reflected in increased growth, photosynthetic activity, and redox balance through the regulation of antioxidant machinery particularly ascorbate-glutathione cycle. We noticed that auxin and NO were also found to be independently participating in Si-mediated improvement of growth and other parameters in barley roots under Pi deficiency. Data of gene expression analysis for PHOSPHATE TRANSPORTER1 (HvPHT1) indicate that Si helps in increasing Pi uptake as per the need of Pi-deficient barley seedlings, and also auxin and NO both appear to help Si in accomplishing this task probably by inducing lateral root formation. These results are suggestive of possible application of Si as a fertilizer to correct the negative effects of nutritional stresses in plants. Further research at genetic level to understand Si-induced mechanisms for mitigating Pi deficiency can be helpful in the development of new varieties with improved tolerance against Pi deficiency, especially for cultivation in areas with Pi-deficient soils.

6-Hydroxy-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline Demonstrates Neuroprotective Properties in Experimental Parkinson's Disease by Enhancing the Antioxidant System, Normalising Chaperone Activity and Suppressing Apoptosis.

Parkinson's disease (PD) is a neurodegenerative disease, whereby disturbances within the antioxidant defence system, increased aggregation of proteins, and activation of neuronal apoptosis all have a crucial role in the pathogenesis. In this context, exploring the neuroprotective capabilities of compounds that sustain the effectiveness of cellular defence systems in neurodegenerative disorders is worthwhile. During this study, we assessed how 6-hydroxy-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline (HTHQ), which has antioxidant properties, affects the functioning of the antioxidant system, the activity of NADPH-generating enzymes and chaperones, and the level of apoptotic processes in rats with rotenone-induced PD. Six groups of animals were formed for our experiment, each with 12 animals. These were: a control group, animals with rotenone-induced PD, rats with PD given HTHQ at a dose of 50 mg/kg, rats with PD given HTHQ at a dose of 25 mg/kg, animals with pathology who were administered a comparison drug rasagiline, and control animals who were administered HTHQ at a dose of 50 mg/kg. The study results indicate that administering HTHQ led to a significant decrease in oxidative stress in PD rats. The enhanced redox status in animal tissues was linked with the recovery of antioxidant enzyme activities and NADPH-generating enzyme function, as well as an upsurge in the mRNA expression levels of antioxidant genes and factors Nrf2 and Foxo1. Administering HTHQ to rats with PD normalized the chaperone-like activity and mRNA levels of heat shock protein 70. Rats treated with the compound displayed lower apoptosis intensity when compared to animals with pathology. Therefore, owing to its antioxidant properties, HTHQ demonstrated a beneficial impact on the antioxidant system, resulting in decreased requirements for chaperone activation and the inhibition of apoptosis processes triggered in PD. HTHQ at a dose of 50 mg/kg had a greater impact on the majority of the examined variables compared to rasagiline.

Oxidative effects of the human antifungal drug clotrimazole on the eucaryotic model organism Saccharomyces cerevisiae.

Clotrimazole is a type of antifungal medication developed from azole compounds. It exhibits several biological actions linked to oxidative stress. This study focuses on the oxidative effects of clotrimazole on the eukaryotic model yeast, Saccharomyces cerevisiae. Our results showed that although initial nitric oxide levels were above control in clotrimazole exposed cells, they showed decreasing tendencies from the beginning of incubation and dropped below control at 125 µM from the 60th min. The highest superoxide anion and hydrogen peroxide levels were 1.95- and 2.85-folds of controls at 125 µM after 15 and 60 min, respectively. Hydroxyl radical levels slightly increased throughout the incubation period in all concentrations and reached 1.3-fold of control, similarly at 110 and 125 µM in the 90th min. The highest level of reactive oxygen species was observed at 110 µM, 2.31-fold of control. Although NADH/NADPH oxidase activities showed similar tendencies for all conditions, the highest activities were found as 3.07- and 2.27-folds of control at 125 and 110 µM in the 15th and 30th min, respectively. The highest superoxide dismutase and catalase activities were 1.59- and 1.21-folds of controls at 110 µM clotrimazole in 30 and 90 min, respectively. While the drug generally induced glutathione-related enzyme activities, the ratios of glutathione to oxidized glutathione were above the control only at low concentrations of the drug. The levels of lipid peroxidation in all treated cells were significantly higher than the controls. The findings crucially demonstrate that this medicine can generate serious oxidative stress in organisms.

Untangling the adaptive strategies of thermophilic bacterium Anoxybacillus rupiensis TPH1 under low temperature.

The present study investigates the low temperature tolerance strategies of thermophilic bacterium Anoxybacillus rupiensis TPH1, which grows optimally at 55 °C , by subjecting it to a temperature down-shift of 10 °C (45 °C) for 4 and 6 h followed by studying its growth, morphophysiological, molecular and proteomic responses. Results suggested that although TPH1 experienced increased growth inhibition, ROS production, protein oxidation and membrane disruption after 4 h of incubation at 45 °C yet maintained its DNA integrity and cellular structure through the increased expression of DNA damage repair and cell envelop synthesizing proteins and also progressively alleviated growth inhibition by 20% within two hours i.e., 6 h, by inducing the expression of antioxidative enzymes, production of unsaturated fatty acids, capsular and released exopolysaccharides and forming biofilm along with chemotaxis proteins. Conclusively, the adaptation of Anoxybacillus rupiensis TPH1 to lower temperature is mainly mediated by the synthesis of large numbers of defense proteins and exopolysaccharide rich biofilm formation.

Exploration of the immune response of grass carp (Ctenopharyngodon idellus) erythrocytes during bacterial infection.

In teleost blood, red blood cells (RBCs) are the most common type of cell, and they differ from mammalian RBCs in having a nucleus and other organelles. As nucleated cells, teleost RBCs contribute to the immune response against pathogens, but their antibacterial mechanism remains unclear. Here, we utilized RNA-Seq to analyze gene expression patterns of grass carp (Ctenopharyngodon idellus) RBCs (GcRBCs) stimulated by Aeromonas hydrophila, Escherichia coli, and Staphylococcus aureus. Our transcriptomic data showed that bacterial stimulation generated many differentially expressed genes (DEGs). Furthermore, several inflammatory pathways responded to bacterial activation, and the TLR, IL-17, and tumor necrosis factor (TNF) signaling pathways were significantly activated based on Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Furthermore, the findings of qRT-PCR showed markedly elevated expression of various cytokines, including IL-1ß, IL4, IL6, IL8, IL12, and TNFα, in GcRBCs after incubation with bacteria. Reactive oxygen species (ROS) production in GcRBCs was markedly increased after the cells were stimulated with the three bacteria, and the expression of superoxide dismutase, glutathione peroxidase, and antioxidant enzymes, including catalase, was altered. Flow cytometry analysis showed that the apoptosis rate of GcRBCs was enhanced after stimulation with the three bacteria for different times. In summary, our findings reveal that bacterial stimulation activates the immune response of GcRBCs by regulating ROS release, cytokine expression, and the antioxidant system, leading to apoptosis of GcRBCs.

Silicon supplementation stabilizes the effect of copper stress, the use of copper chaperones and genes involved: a review.

Heavy metal stress is a major problem in present scenario and the consequences are well known. The agroecosystems are heavily affected by the heavy metal stress and the question arises on the sustainability of the agricultural products. Heavy metals inhibit the process to influence the reactive oxygen species production. When abundantly present copper metal ion has toxic effects which is mitigated by the exogenous application of Si. The role of silicon is to enhance physical parameters as well as gas exchange parameters. Si is likely to increase antioxidant enzymes in response to copper stress which can relocate toxic metals at subcellular level and remove heavy metals from the cell. Silicon regulates phytohormones when excess copper is present. Rate of photosynthesis and mineral absorption is increased in response to metal stress. Silicon manages enzymatic and non-enzymatic activities to balance metal stress condition. Cu transport by the plasma membrane is controlled by a family of proteins called copper transporter present at cell surface. Plants maintain balance in absorption, use and storage for proper copper ion homeostasis. Copper chaperones play vital role in copper ion movement within cells. Prior to that metallochaperones control Cu levels. The genes responsible in copper stress mitigation are discovered in various plant species and their function are decoded. However, detailed molecular mechanism is yet to be studied. This review discusses about the crucial mechanisms of Si-mediated alleviation of copper stress, the role of copper binding proteins in copper homeostasis. Moreover, it also provides a brief information on the genes, their function and regulation of their expression in relevance to Cu abundance in different plant species which will be beneficial for further understanding of the role of silicon in stabilization of copper stress.

Lisdexamfetamine dimesylate-exposition in male rats during the peripubertal period impairs inflammatory mechanisms, antioxidant activity, and apoptosis process in kidneys of male pubertal rats.

Lisdexamfetamine dimesylate (LDX) is a prodrug of dextroamphetamine, which has been widely recommended for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD). There are still no data in the literature relating the possible toxic effects of LDX in the kidney. Therefore, the present study aims to evaluate the effects of LDX exposure on morphological, oxidative stress, cell death and inflammation parameters in the kidneys of male pubertal Wistar rats, since the kidneys are organs related to the excretion of most drugs. For this, twenty male Wistar rats were distributed randomly into two experimental groups: LDX group-received 11,3 mg/kg/day of LDX; and Control group-received tap water. Animals were treated by gavage from postnatal day (PND) 25 to 65. At PND 66, plasma was collected to the biochemical dosage, and the kidneys were collected for determinations of the inflammatory profile, oxidative status, cell death, and for histochemical, and morphometric analyses. Our results show that there was an increase in the number of cells marked for cell death, and a reduction of proximal and distal convoluted tubules mean diameter in the group that received LDX. In addition, our results also showed an increase in MPO and NAG activity, indicating an inflammatory response. The oxidative status showed that the antioxidant system is working undisrupted and avoiding oxidative stress. Therefore, LDX-exposition in male rats during the peripubertal period causes renal changes in pubertal age involving inflammatory mechanisms, antioxidant activity and apoptosis process.

The regulation and function of Nrf2 signaling in ferroptosis-activated cancer therapy.

Ferroptosis is an iron-dependent programmed cell death process that involves lipid oxidation via the Fenton reaction to produce lipid peroxides, causing disruption of the lipid bilayer, which is essential for cellular survival. Ferroptosis has been implicated in the occurrence and treatment response of various types of cancer, and targeting ferroptosis has emerged as a promising strategy for cancer therapy. However, cancer cells can escape cellular ferroptosis by activating or remodeling various signaling pathways, including oxidative stress pathways, thereby limiting the efficacy of ferroptosis-activating targeted therapy. The key anti-oxidative transcription factor, nuclear factor E2 related factor 2 (Nrf2 or NFE2L2), plays a dominant role in defense machinery by reprogramming the iron, intermediate, and glutathione peroxidase 4 (GPX4)-related network and the antioxidant system to attenuate ferroptosis. In this review, we summarize the recent advances in the regulation and function of Nrf2 signaling in ferroptosis-activated cancer therapy and explore the prospect of combining Nrf2 inhibitors and ferroptosis inducers as a promising cancer treatment strategy.

Polyvinylpyrrolidone-coated copper nanoparticles dose-dependently conferred tolerance to wheat under salinity and/or drought stress by improving photochemical activity and antioxidant system.

Copper (Cu) is one of the essential micronutrients for plants and has been used extensively in agricultural applications from the past to the present. However, excess copper causes toxic effects such as inhibiting photosynthesis, and disrupting biochemical processes in plants. Nanotechnology applications have offered a critical method for minimizing adverse effects and improving the effectiveness of copper nanoparticles. For this purpose, this study investigated the physiological and biochemical effects of polyvinylpyrrolidone (PVP)-coated Cu nanoparticles (PVP-Cu NP, N1, 100 mg L-1; N2, 400 mg L-1) in Triticum aestivum under alone or combined with salt (S, 150 mM NaCl) and/or drought (D, %10 PEG-6000) stress. Salinity and water deprivation caused 51% and 22% growth retardation in wheat seedlings. The combined stress condition (S + D) resulted in an approximately 3-fold reduction in the osmotic potential of the leaves. PVP-Cu NP treatments to plants under stress, especially N1 dose, were effective in restoring growth rate and regulating water relations. All stress treatments limited gas exchange in stomata and suppressed the maximal quantum yield of PSII (Fv/Fm). More than 50% improvement was observed in stomatal permeability and carbon assimilation rate under S + N1 and S + N2 applications. Examination of OJIP transient parameters revealed that N1 treatments protected photochemical reactions by reducing the dissipated energy flux (DIo/RC) in drought and S + D conditions. Exposure to S and/or D stress caused high hydrogen peroxide (H2O2) accumulation and lipid peroxidation in wheat leaves. The results indicated that S + N1 and S + N2 treatments reduced oxidative damage by stimulating the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POX), and ascorbate peroxidase (APX). Although similar effects were observed at D and S + D conditions with 100 mg L-1 PVP-Cu NP treatments (N1), the curative effect of the N2 dose was not observed. In D + N1 and S + D + N1 groups, AsA regeneration and GSH redox status were maintained by triggering APX, GR, and other enzyme activities belonging to the AsA-GSH cycle. In these groups, N2 treatment did not contribute to the availability of enzymatic and non-enzymatic antioxidants. As a result, this study revealed that N1 dose PVP-Cu NP application was successful in providing stress tolerance and limiting copper-induced adverse effects under all stress conditions.

The interplay between doxorubicin chemotherapy, antioxidant system, and cardiotoxicity: Unrevealing of the protective potential of tannic acid.

Cardiotoxicity is the leading side effect of anthracycline-based chemotherapy. Therefore, it has gained importance to reveal chemotherapy-supporting strategies and reliable agents with their mechanisms of action. Tannic acid (TA), a naturally occurring plant polyphenol, has diverse physiological effects, including anti-inflammatory, anticarcinogenic, antioxidant, and radical scavenging properties. Therefore, this study was designed to investigate whether TA exerts a protective effect on mechanisms contributing to anthracycline-induced cardiotoxicity in rat heart tissues exposed to doxorubicin (DOX). Rats were randomly divided into control and experimental groups and treated with (18 mg/kg) DOX, TA (50 mg/kg), and DOX + TA during the 2 weeks. Cardiac gene markers and mitochondrial DNA (mtDNA) content were evaluated in the heart tissues of all animals. In addition to major metabolites, mRNA expression changes and biological activity responses of components of antioxidant metabolism were examined in the heart tissues of all animals. The expression of cardiac gene markers increased by DOX exposure was significantly reduced by TA treatment, whereas mtDNA content, which was decreased by DOX exposure, was significantly increased. TA also improved antioxidant metabolism members' gene expression and enzymatic activity, including glutathione peroxidase, glutathione s-transferase, superoxide dismutase, catalase, and thioredoxin reductase. This study provides a detailed overview of the current understanding of DOX-induced cardiotoxicity and preventive or curative measures involving TA.

Response of photosynthetic characteristics and antioxidant system in the leaves of safflower to NaCl and NaHCO3.

KEY MESSAGE: Compared with NaCl, NaHCO3 caused more serious oxidative damage and photosynthesis inhibition in safflower by down-regulating the expression of related genes. Salt-alkali stress is one of the important factors that limit plant growth. NaCl and sodium bicarbonate (NaHCO3) are neutral and alkaline salts, respectively. This study investigated the physiological characteristics and molecular responses of safflower (Carthamus tinctorius L.) leaves treated with 200 mmol L-1 of NaCl or NaHCO3. The plants treated with NaCl treatment were less effective at inhibiting the growth of safflower, but increased the content of malondialdehyde (MDA) in leaves. Meanwhile, safflower alleviated stress damage by increasing proline (Pro), soluble protein (SP), and soluble sugar (SS). Both fresh weight and dry weight of safflower was severely decreased when it was subjected to NaHCO3 stress, and there was a significant increase in the permeability of cell membranes and the contents of osmotic regulatory substances. An enrichment analysis of the differentially expressed genes (DEGs) using Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes identified significant enrichment of photosynthesis and pathways related to oxidative stress. Furthermore, a weighted gene co-expression network analysis (WGCNA) showed that the darkgreen module had the highest correlation with photosynthesis and oxidative stress traits. Large numbers of transcription factors, primarily from the MYB, GRAS, WRKY, and C2H2 families, were predicted from the genes within the darkgreen module. An analysis of physiological indicators and DEGs, it was found that under saline-alkali stress, genes related to chlorophyll synthesis enzymes were downregulated, while those related to degradation were upregulated, resulting in inhibited chlorophyll biosynthesis and decreased chlorophyll content. Additionally, NaCl and NaHCO3 stress downregulated the expression of genes related to the Calvin cycle, photosynthetic antenna proteins, and the activity of photosynthetic reaction centers to varying degrees, hindering the photosynthetic electron transfer process, suppressing photosynthesis, with NaHCO3 stress causing more pronounced adverse effects. In terms of oxidative stress, the level of reactive oxygen species (ROS) did not change significantly under the NaCl treatment, but the contents of hydrogen peroxide and the rate of production of superoxide anions increased significantly under NaHCO3 stress. In addition, treatment with NaCl upregulated the levels of expression of the key genes for superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), the ascorbate-glutathione cycle, and the thioredoxin-peroxiredoxin pathway, and increased the activity of these enzymes, thus, reducing oxidative damage. Similarly, NaHCO3 stress increased the activities of SOD, CAT, and POD and the content of ascorbic acid and initiated the glutathione-S-transferase pathway to remove excess ROS but suppressed the regeneration of glutathione and the activity of peroxiredoxin. Overall, both neutral and alkaline salts inhibited the photosynthetic process of safflower, although alkaline salt caused a higher level of stress than neutral salt. Safflower alleviated the oxidative damage induced by stress by regulating its antioxidant system.