H2O2 Levels Research Articles

Ecotoxicological Effects of Paracetamol on the Biochemical and Molecular Responses of Spinach (Spinacia oleracea L.)

The widespread use of pharmaceuticals, including paracetamol, has raised concerns about their impact on the environment and non-target species. The aim of this study was to investigate the biochemical and molecular responses of Spinacia oleracea (spinach) to high paracetamol concentrations in order to understand the plant's stress responses and underlying mechanisms. Under controlled conditions, spinach plants were exposed to different paracetamol concentrations (0, 50, 100, and 200mg/L). The study evaluated the impact of paracetamol exposure on biochemical parameters such as oxidative stress markers (H2O2, MDA), activities of antioxidant enzymes (APX, CAT, GPOD, SOD), levels of non-enzymatic components (phenolics and flavonoids), and phytohormones (ABA, SA, and IAA). Furthermore, the study assessed molecular impacts by analyzing stress-related genetic variation and alterations in the gene expression of the antioxidant enzymes. Results showed that paracetamol exposure significantly increased oxidative stress in spinach, which was evident through the elevated H2O2 and MDA levels. However, the antioxidant defense mechanisms were activated to counteract this effect, as evidenced by increased activity of antioxidant enzymes and higher phenolics and flavonoid levels. Moreover, induction in the phytohormone levels indicated a stress response in paracetamol-treated plants compared to control plants. RAPD analysis revealed polymorphism indicating the DNA damage, and the Real-time qRT-PCR method showed significant upregulation of stress-responsive genes, highlighting the severe impact of paracetamol at the molecular level. The study concludes that high paracetamol concentrations pose a significant threat to spinach growth by affecting both biochemical and molecular processes. These findings underscore the need for strict environmental management practices to mitigate the possible impact of continuous release, accumulation, and long-term exposure of pharmaceutical contaminants to the environment and implement policies to reduce pharmaceutical pollutants to preserve ecological health and biodiversity.

A Supramolecular Self-Assembled Nanoprodrug for Enhanced Ferroptosis Therapy.

Ferroptosis can induce cell death that leverages Fe2+-triggered Fenton reactions within living organisms, leading to an excessive accumulation of lipid peroxides (LPOs) and inducing cell death. Ferroptosis can effectively circumvent the inevitable drug resistance encountered with traditional apoptotic therapies. However, several issues remain in the clinical application of ferroptosis anticancer therapy, primarily due to the poor efficiency of intracellular Fenton reaction. To address this issue, we developed a supramolecular self-assembled codelivery nanoprodrug (DOX@C18Fc-Q[7] NPs) composed of ferrocene (Fc)-based supramolecular amphiphiles (C18Fc-Q[7]) and a nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) activator (doxorubicin, DOX). The C18Fc-Q[7] is based on Fc linked to a hydrophobic long-chain alkane via a disulfide linkage, which interacts with hydrophilic Q[7] to form self-assembled amphiphiles. Importantly, the host-guest interaction between Q[7] and Fc effectively enhances the solubility of Fc while maintaining the stability of the Fe2+ source. Moreover, C18Fc-Q[7] also acts as a good carrier for loading DOX due to its good self-assembly. In cancer cells, elevated glutathione (GSH) triggers the disassembly of nanoprodrug, leading to the release of DOX, which upregulates NOX4 expression and increases H2O2 level, thereby promoting an efficient Fenton reaction for Fc-induced ferroptosis. Moreover, DOX induces cell death through apoptosis, providing a synergistic effect to further enhance the ferroptosis therapy. In vivo studies have demonstrated that this enhanced ferroptosis therapy effectively inhibits tumor growth and metastasis while maintaining good biosafety.

Combining multiple stressors blocks bacterial migration and growth.

In nature, organisms experience combinations of stressors. However, laboratory studies use batch cultures, which simplify reality and focus on population-level responses to individual stressors.1,2,3,4,5 In recent years, bacterial stress responses have been examined with single-cell resolution using microfluidics.6,7,8,9,10,11,12 Here, we use a microfluidic approach to simultaneously provide a physical stressor (shear flow) and a chemical stressor (H2O2) to the human pathogen Pseudomonas aeruginosa. By treating cells with levels of flow and H2O2 that commonly co-occur in human host tissues,13,14,15,16,17,18 we discover that previous reports significantly overestimate the H2O2 levels required to block bacterial growth. Specifically, we establish that flow increases H2O2 effectiveness 50-fold, explaining why previous studies lacking flow required much higher concentrations. Using natural H2O2 levels, we identify the core H2O2 regulon, characterize OxyR-mediated dynamic regulation, and demonstrate that multiple H2O2 scavenging systems have redundant roles. By examining single-cell behavior, we serendipitously discover that the combined effects of H2O2 and flow block pilus-driven surface migration. Thus, our results counter previous studies and reveal that natural levels of H2O2 and flow synergize to restrict bacterial motility and survival. By studying two stressors at once, our research highlights the limitations of oversimplifying nature and demonstrates that physical and chemical stress can combine to yield unpredictable effects.

Exogenous Sodium Nitroprusside Exhibits Multiple Positive Roles in Alleviating Cadmium Toxicity in Tobacco (Nicotiana tabacum L.).

As a donor of the gaseous signaling molecule nitric oxide (NO), sodium nitroprusside (SNP) has been shown to play a positive role in enhancing plant resistance to abiotic stress. However, its role in alleviating cadmium (Cd) toxicity in tobacco (Nicotiana tabacum L.) is not fully understood. This study found that Cd stress significantly inhibited tobacco growth. At the same time, 150 μM SNP was the most effective concentration in alleviating Cd toxicity in seedlings, restoring three stress tolerance indicators-MDA, H2O2, and proline-to control levels. Exogenous SNP mitigated Cd-induced oxidative stress by promoting the accumulation of non-enzymatic antioxidants (total phenolics and flavonoids) and activating key antioxidant enzymes (SOD, CAT, POD, APX, and GR) along with their gene expression. SNP also facilitated Cd accumulation in the root cell wall and prevented Cd translocation from roots to shoots. Additionally, SNP altered Cd's subcellular distribution, promoting its sequestration in vacuoles and cell walls, which may be related to the NO-mediated upregulation of the metallothionein gene NtMT2F and the phytochelatin gene NtPCS2. The addition of SNP significantly increased the proportion of Cd in less toxic chemical forms, with the residual Cd fraction in the Cd + SNP group reaching 7.30%, higher than the 4.86% in the Cd-only group. Furthermore, exogenous SNP counteracted Cd's inhibition of nitrate reductase (NR) activity, promoting endogenous NO production. This study systematically reveals the positive roles of exogenous SNP in mitigating Cd toxicity in tobacco, offering valuable insights for producing low-Cd tobacco.

Elucidating the protective role of manganese seed priming in mitigating lead-induced oxidative stress: enhancements in growth, grain yield, and antioxidant activities of wheat.

Lead (Pb) is known to be extremely toxic to plants and awfully affects growth and productivity by interacting with morphological, biochemical, and physiological processes. Micronutrients are considered to reduce ion toxicity and modify various physiological processes involved in oxidative stress tolerance in plants. Hence, the limited literature about the application of micronutrients, particularly manganese (Mn), under lead stress thus demands more investigations. To sort out the role of priming treatments of Mn (1.0 and 0.1mg/L) in lead stress (200mg/kg) induced oxidative stress tolerance in wheat cultivars (Anaj-17 and Akbar-19), current experiment was designed. The experiment was arranged with completely randomized design (CRD) with three replicates. The results explored the positive role of Mn priming in strengthening the antioxidant system with increased activities of antioxidants under Pb stress. Mn priming level (0.1mg/L) significantly increased the germination percentage, germination percentage, growth traits, grain yield per plant, shoot P, shoot Ca2+, and shoot K+ while decreasing the MDA and H2O2 levels, of Anaj-17 and Akbar-19 under Pb stress (200mg/kg). Seed priming levels of Mn further upgraded the antioxidant enzymatic activities and organic osmolytes such as proline, total phenolics, flavonoids, total soluble sugars, and glycine betaine, under Pb stress. Conclusively, the 0.1mg/L level of Mn priming and Akbar-19 cultivar has proven superior in lead detoxification under Pb-induced oxidative stress. Furthermore, the outcomes revealed more accumulation of Pb in the roots of wheat than in the shoots of both wheat cultivars and emphasized the use of lower Mn levels of 0.1mg/L as the best strategy in alleviating the toxic impacts of lead in wheat. However, the conduct of large field trials is a necessity of current scenario to study the molecular aspects and associated genes contributing Pb stress tolerance with priming application of Mn and other micronutrients.

Coordination-Driven in Situ Grown Copper Peroxide in Mesoporous Dopamine with Self-Supplied H2O2 for Synergistic Enhanced PTT/CDT Antibacterial Treatment and Wound Healing.

As antibiotic resistance increases, alternative antimicrobial methods become essential. Chemical dynamics therapy (CDT) utilizing copper peroxide (CuO2) nanodots shows significant potential in antibacterial applications due to its ability to self-supply hydrogen peroxide (H2O2) on its own. This characteristic effectively addresses the challenges of low H2O2 levels and high glutathione (GSH) expression in the bacterial infection microenvironment. However, its tendency to aggregate and instability greatly affect its effectiveness. Therefore, this study developed a coordination-driven strategy to prepare copper peroxide-loaded mesoporous polydopamine nanomaterials (CuO2@MPDA) through in situ growth of CuO2 in mesoporous polydopamine utilizing the chelating interaction between amino and catechol structures of MPDA with copper ions. This strategy not only ensures that copper peroxide is evenly distributed within the pores of mesoporous polydopamine but also protects it through the shielding effect of pores, greatly enhancing its dispersibility and stability. More notably, the loading of CuO2 enhances the photothermal performance of MPDA by broadening its light absorption range, and MPDA-mediated photothermal therapy (PTT) can accelerate CuO2 to produce more hydroxyl radicals by speeding up chemical reactions, resulting in a combined boost in PTT and CDT. The developed CuO2@MPDA nanomaterials at very low concentrations exhibit improved antibacterial efficiency both in vitro and in vivo. Overall, this study provides an innovative strategy to construct an antibacterial nanoplatform for synergistically enhanced PTT/CDT dual-mode antibacterial treatment, exhibiting great potential for future biomedical applications.

Decoding the Impact of a Bacterial Strain of Micrococcus luteus on Arabidopsis Growth and Stress Tolerance

Microbes produce various bioactive metabolites that can influence plant growth and stress tolerance. In this study, a plant growth-promoting rhizobacterium (PGPR), strain S14, was identified as Micrococcus luteus (designated as MlS14) using de novo whole-genome assembly. The MlS14 genome revealed major gene clusters for the synthesis of indole-3-acetic acid (IAA), terpenoids, and carotenoids. MlS14 produced significant amounts of IAA, and its volatile organic compounds (VOCs), specifically terpenoids, exhibited antifungal activity, suppressing the growth of pathogenic fungi. The presence of yellow pigment in the bacterial colony indicated carotenoid production. Treatment with MlS14 activated the expression of β-glucuronidase (GUS) driven by a promoter containing auxin-responsive elements. The application of MlS14 reshaped the root architecture of Arabidopsis seedlings, causing shorter primary roots, increased lateral root growth, and longer, denser root hairs; these characteristics are typically controlled by elevated exogenous IAA levels. MlS14 positively regulated seedling growth by enhancing photosynthesis, activating antioxidant enzymes, and promoting the production of secondary metabolites with reactive oxygen species (ROS) scavenging activity. Pretreatment with MlS14 reduced H2O2 and malondialdehyde (MDA) levels in seedlings under drought and heat stress, resulting in greater fresh weight during the post-stress period. Additionally, exposure to MlS14 stabilized chlorophyll content and growth rate in seedlings under salt stress. MlS14 transcriptionally upregulated genes involved in antioxidant defense and photosynthesis. Furthermore, genes linked to various hormone signaling pathways, such as abscisic acid (ABA), auxin, jasmonic acid (JA), and salicylic acid (SA), displayed increased expression levels, with those involved in ABA synthesis, using carotenoids as precursors, being the most highly induced. Furthermore, MlS14 treatment increased the expression of several transcription factors associated with stress responses, with DREB2A showing the highest level of induction. In conclusion, MlS14 played significant roles in promoting plant growth and stress tolerance. Metabolites such as IAA and carotenoids may function as positive regulators of plant metabolism and hormone signaling pathways essential for growth and adaptation to abiotic stress.

Engineered nanoplatform mediated gas therapy enhanced ferroptosis for tumor therapy in vivo

The high glutathione (GSH) environment poses a significant challenge for inducing ferroptosis in tumor cells, necessitating the development of nanoplatforms that can deplete intracellular GSH. In this study, we developed an engineered nanoplatform (MIL-100@Era/L-Arg-HA) that enhances ferroptosis through gas therapy. First, we confirmed that the Fe element in the nanoplatform undergoes valence changes under the influence of high GSH and H2O2 in tumor cells. Meanwhile, L-Arg generates NO gas in the presence of intracellular H2O2, which reacts with GSH. Additionally, Erastin depletes GSH by inhibiting the cystine/glutamate antiporter system, reducing cystine uptake and impairing GPX4, while also increasing intracellular H2O2 levels by activating NOX4 protein expression. Through these combined GSH-depletion mechanisms, we demonstrated that MIL-100@Era/L-Arg-HA effectively depletes GSH levels, disrupts GPX4 function, and increases intracellular lipid ROS levels in vitro. Furthermore, this nanoplatform significantly inhibited tumor cell growth and extended the survival time of tumor-bearing mice in vivo. This engineered nanoplatform, which enhances ferroptosis through gas therapy, shows significant promise for ferroptosis-based cancer therapy and offers potential strategies for clinical tumor treatment.

A novel colorimetric assay for the detection of urinary N1, N12-diacetylspermine, a known biomarker for colorectal cancer

Urinary N1, N12-diacetylspermine (DAS) is a known biomarker for colorectal cancer (CRC). However, DAS levels in both healthy and CRC patients’ urine samples are extremely low and often challenging to quantify. Complex and expensive methods do exist to detect DAS in urine, but simpler, less expensive methods to detect DAS are needed, especially in low resource settings. Here we describe a highly efficient, fast, precise, and inexpensive colorimetric assay to detect low levels of DAS in human urine samples. We used recombinant diacetylspermine oxidase (rDAS Ox), expressed and extracted from E. coli, to oxidize DAS, producing three products including hydrogen peroxide (H2O2). The level of DAS present, which correlates with H2O2 levels, was measured using horseradish peroxidase (HRP), which together with H2O2, oxidized Amplex™ Red to produce the pink-colored resorufin. The concentration of resorufin is directly proportional to H2O2 (and DAS) levels. As urine contains metabolites which interfere with these oxidation reactions, we developed a simple two column-based protocol using ion exchange resins to remove these compounds and concentrate the DAS. With this novel cleaning and concentrating method, DAS was concentrated 15 times (confirmed by nuclear magnetic resonance (NMR) spectroscopy) and <1 μM DAS could be detected. Correlation graphs of urine samples spiked with known DAS concentrations versus assay-determined DAS concentrations had high coefficients of determination (R2) for 0-10 μM DAS (0.94) and for 0-1 μM DAS (0.91), clearly demonstrating the excellent performance of the two-column protocol with the rDAS Ox reaction mixture. To the best of our knowledge, this is first reported colorimetric enzymatic assay that quantitates DAS in urine.

Polyethylene microplastic modulates the toxicity of pentachlorophenol to the microalgae Isochrysis galbana, clone t-ISO

Pentachlorophenol (PCP) and polyethylene microplastic (PE-MP) have been designated as emerging and persistent pollutants, respectively. The combined effects of those pollutants are still unknown, especially to organisms like phytoplankton that may adsorb to their surface. Therefore, the purpose of this study was to investigate for the first time the effects of PE-MP alone and in combination with PCP on the microalgae Isochrysis galbana, clone t-ISO following 72 h of exposure. Photosynthetic pigments amounts, carotenoid, protein, carbohydrate and fatty acids have been assessed. Acute toxicity test showed that the 72 h median inhibition concentration (72 h-EC50) was 148.2, 0.66 and 087 mg L−1 for PE-MP, PCP and their mixture. The utmost effects in growth inhibition rates were noted with 0.5 and 1.25 mg L−1 PCP (23% and 85%, respectively), and 100 and 300 mg L−1 PE-MP (49% and 64%, respectively). Moreover, it was found that those concentrations had a major impact on the photosynthetic pigments, protein, carbohydrate, and fatty acids amounts in algal cells. Furthermore, levels of H2O2 and Malondialdehyde (MDA), as well as the activities of catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX), indicated the induction of an oxidative stress in algal cells. It appears that adding PE-MP at a no-effect concentration (25 mg L−1) reduces the toxicity caused by PCP due to its adsorption to polyethylene microplastics.

Overexpression of tae-miR9670 enhances cadmium tolerance in wheat by targeting mTERFs without yield penalty

Cadmium (Cd) is a widely distributed heavy metal that poses significant hazards to both crop productivity and human health. MicroRNAs (miRNAs) play pivotal roles in plant growth, development and responses to environmental stresses, yet little is known about their roles in regulating Cd tolerance in wheat. In this study, we identified tae-miR9670, a Triticeae-specific miRNA, as responsive to Cd exposure in wheat through miRNAome analysis. Tae-miR9670 can target genes that encode mitochondrial transcription termination factors (mTERFs), mediating their mRNA cleavage and suppressing their expression. Overexpression of tae-miR9670 significantly enhanced Cd tolerance in wheat seedlings, as demonstrated by increased biomass and reduced levels of malondialdehyde (MDA), H2O2, and Cd content. Consequently, multiple downstream genes involved in ROS scavenging, detoxification and heavy metal transport were upregulated in tae-miR9670 overexpression plants. Moreover, the grain Cd content in mature plants overexpressing tae-miR9670 was reduced by over 60% compared to wild-type controls. Our results also indicated that overexpressing tae-miR9670 in wheat preserved yield-related traits, thereby overcoming the trade-off between stress resistance and grain yield. Overall, our findings provide new insights into the role of tae-miR9670 in Cd tolerance in wheat and its potential application in breeding low-Cd cultivars.

AQP1 mediates pancreatic β cell senescence induced by metobolic stress through modulating intracellular H2O2 level

AQP1 mediates pancreatic β cell senescence induced by metobolic stress through modulating intracellular H2O2 level

Daphnetin Protects Schwann Cells Against High-Glucose-Induced Oxidative Injury by Modulating the Nuclear Factor Erythroid 2-Related Factor 2/Glutamate-Cysteine Ligase Catalytic Subunit Signaling Pathway.

Diabetic peripheral neuropathy (DPN), a common complication of diabetes mellitus, is primarily characterized by damage to Schwann cells caused by oxidative stress under hyperglycemic conditions. Recently, we demonstrated the ability of coumarin-rich Ficus formosana Maxim. to alleviate DPN in ovariectomized diabetic mice. However, the underlying mechanisms remain unclear. In this study, we established an in vitro DPN model using RSC96 Schwann cells exposed to high glucose levels. Daphnetin, a natural coumarin found abundantly in Ficus formosana Maxim., was co-incubated with Schwann cells in a high-glucose medium to investigate its protective effects against DPN. The free radical scavenging capacity of daphnetin was evaluated, along with assessments of cell viability, apoptosis, H2O2 levels, and the expression of proteins by the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutamate-cysteine ligase catalytic subunit (GCLC) pathway in RSC96 Schwann cells. The results showed that daphnetin was non-toxic within the tested concentration range of 6.25 μM to 50 μM in RSC96 Schwann cells. Moreover, daphnetin significantly improved cell viability, exhibited strong antioxidant activity, reduced H2O2 levels, and regulated the Nrf2/GCLC pathway protein expressions in RSC96 cells cultured in high-glucose medium. Additionally, daphnetin influenced apoptosis-related proteins by decreasing the expression levels of Bax and Caspase 3, while increasing the Bcl-2 expression level in high-glucose-treated RSC96 cells. These findings suggest that daphnetin may alleviate oxidative stress induced by high glucose levels through activation of the Nrf2/GCLC pathway and inhibition of Schwann cell apoptosis, underscoring its potential as a therapeutic agent for DPN.

Anti-inflammatory effects of a methanol extract from Montanoa grandiflora DC. (Asteraceae) leaves on in vitro and in vivo models.

Montanoa grandiflora, a plant species native from Mexico to Central America, locally known as "Teresita" in Yucatán, México, is used to alleviate anxiety, rheumatism, and stomach issues. This study aims to investigate the anti-inflammatory properties of the methanol extract of Montanoa grandiflora leaves (MMG) in experimental models of inflammation. Gas chromatography-mass spectroscopy was used to characterize the MMG; cytotoxicity was assessed by MTT assay on murine macrophages and hemolysis assay. The in vitro anti-inflammatory activity was evaluated on LPS-stimulated murine macrophages by measuring of pro- and anti-inflammatory cytokines, NO and H2O2 release. The in vivo anti-inflammatory activity was evaluated using carrageenan-induced mouse paw edema, 12-O-tetradecanoylphorbol 13-acetate induced-ear edema, and 1-fluoro-2,4-dinitrobenzene induced-delayed-type hypersensitivity. In addition, the serum levels of prostaglandins and leukotrienes were assessed. The main compounds found in MMG were terpenes (i.e., β-caryophyllene, (-)-α-cubebene, alloaromadendrene, ( +)-δ-cadinene, β-eudesmol), alkaloid (( ±)-nor-β-hydrastine), cyclic polyol (quinic acid), carbohydrates and their derivatives, and fatty acids (octadecatrienoic acid and octadecanoic acid). MMG did not exhibit cytotoxic or hemolytic activity. However, it demonstrated in vitro anti-inflammatory effects by increasing the production of IL-10, decreasing the levels of TNF-α, IL-1β, IL-6, NO and H2O2. MMG significantly reduced carrageenan-induced paw edema, TPA-induced ear edema, and DNFB-induced delayed-type hypersensitivity in mice with effects comparable to those of standard drugs, as well as serum levels of prostaglandins and leukotrienes. The anti-inflammatory activity of MMG is associated with increased IL-10 levels and inhibiting inflammatory cell migration mechanisms, without causing cytotoxic or hemolytic damage in both in vitro and in vivo assays.

Ethnopharmacological insights: hyperoside from Marsdenia latifolia (Benth.) K.Schum. mitigates reproductive toxicity in male Wistar rats induced by manganese exposure

This study provides novel findings on the ameliorative effect of hyperoside isolated from Marsdenia latifolia leaves (HIGLL) in reproductive health challenged by manganese toxicity. The study investigated the efficacy of HIGLL on male fertility in rats exposed to manganese chloride (MnCl2). The rats received either MnCl2 (30 mg/L) or in combination with HIGLL (100 mg/kg or 200 mg/kg). MnCl2 reduced fluid intake, organ-body weight, body weight; sperm count, sperm viability, sperm density, sperm motility, semen viscosity, daily sperm production, testicular sperm number; testosterone, follicle-stimulating and luteinising hormones, oestradiol, testosterone/oestradiol ratio; G6PDH, ALP, glucose, NO, acid phosphatase, sialic acid, 17-β-HSD, superoxide dismutase, CAT, GST, GSH, and T-SH without modifying the semen pH and volume, while it correspondingly raised the abnormalities associated with morphology of sperm cells in head, neck, and tail; H2O2 and lipid peroxidation levels. HIGLL abrogated the damaged histoarchitecture of the testes and epididymis caused by MnCl2. HIGLL can serve as a therapeutic agent in the management of male reproductive disorders related to oxidative stress and endocrine disruption.

Effects of nickel, lead, and copper stress on the growth and biochemical responses of Aegilops tauschii seedlings

Heavy metal pollution causes severe abiotic stress in cereal crops around the world. This study investigated the effects of different concentrations (0, 100, 200, and 300 mg·kg–1) of nickel, lead, and copper stress on the growth and biochemical responses of Aegilops tauschii seedlings, to provide a reference for research on the mechanism of invasion and screening potential sources of wheat tolerance genes. The results showed that nickel, lead, and copper stress caused a significant decrease in the contents of chlorophyll a, chlorophyll b, and chlorophyll (a + b) in A. tauschii, thereby inhibiting photosynthesis to different degrees and hindering seedling growth, which was reflected in significant reductions in plant height and root length, with the most notable effect observed under stress by 300 mg·kg–1 lead. As the concentration of heavy metals increased, the activities of antioxidant enzymes (SOD, POD, and APX), non-enzymatic antioxidants (GSH and AsA), and the contents of osmotic regulatory substances (proline and soluble proteins) in A. tauschii significantly increased. Additionally, heavy metal stress increased H2O2 and TBARS levels. However, when the nickel, lead, and copper concentrations reached 300 mg·kg–1, no significant differences were found in H2O2 or TBARS levels compared to those in the CK group. To summarize, A. tauschii can mitigate the accumulation of ROS and membrane lipid peroxidation caused by heavy metal stress through self-regulation, thus exhibiting a certain degree of tolerance to stress caused by different concentrations of nickel, lead, and copper. Finally, the evaluation using the membership function method revealed that among the three heavy metals, A. tauschii exhibited the strongest adaptation to Cu, followed by Ni and Pb.

Metabolomic analysis of the browning and browning inhibition pulp of Fuji apple at different ripening stages

Apples at different ripening stages display distinct processing properties and browning characteristics in products. This study aimed to identify differential metabolites and metabolic pathways of browning pulp and browning inhibition pulp of Fuji apple across four ripening stages (M1–M4), corresponding to days after full bloom (DAFB: 148, 155, 162, and 171). We investigated the physicochemical characteristics, browning-related enzyme activities, and metabolomic profiles of apples at the four stages, revealing defensive metabolic changes associated with browning throughout ripening. Specifically, the browning rate in apples increased with ripening, peaking before declining in the late stages, and exhibited positive correlations with activities of polyphenol oxidase (PPO), peroxidase (POD), and catalase (CAT), and negative correlations with superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), and H2O2 levels. Metabolomic profiling identified 315, 393, and 243 distinct metabolites in fresh control (FC), browning pulp (BR), and browning-inhibited pulps (CM) of apple at the four ripening stages, respectively. KEGG enrichment analysis revealed that FC and BR of the four ripening apples were differentiated by phenylpropanoid biosynthesis, while CM was featured by flavonoid biosynthesis. The characterized differential metabolites in BR were changed to α-linolenic acid metabolism with ripening, while those in CM were from flavonoid and phenylpropanoid biosynthesis. Furthermore, the in-depth analysis revealed 40 significantly differential metabolites associated with amino acid, nucleotide, coenzyme, and vitamin metabolism, potentially modulating the stress-responsive cellular redox balance. This research provides critical insights for browning prevention in the processing of fruits at various ripening stages.

Cerium Oxide Nanoparticles (CeO2 NPs) Enhance Salt Tolerance in Spearmint (Mentha spicata L.) by Boosting the Antioxidant System and Increasing Essential Oil Composition

Salinity represents a considerable environmental risk, exerting deleterious effects on horticultural crops. Nanotechnology has recently emerged as a promising avenue for enhancing plant tolerance to abiotic stress. Among nanoparticles, cerium oxide nanoparticles (CeO2 NPs) have been demonstrated to mitigate certain stress effects, including salinity. In the present study, the impact of CeO2 NPs (0, 25, and 100 mg L−1) on various morphological traits, photosynthetic pigments, biochemical parameters, and the essential oil profile of spearmint plants under moderate (50 mM NaCl) and severe (100 mM NaCl) salinity stress conditions was examined. As expected, salinity reduced morphological parameters, including plant height, number of leaves, fresh and dry weight of leaves and shoots, as well as photosynthetic pigments, in comparison to control. Conversely, it led to an increase in the content of proline, total phenols, malondialdehyde (MDA), hydrogen peroxide (H2O2), and antioxidant enzyme activities. In terms of CeO2 NP applications, they improved the salinity tolerance of spearmint plants by increasing chlorophyll and carotenoid content, enhancing antioxidant enzyme activities, and lowering MDA and H2O2 levels. However, CeO2 NPs at 100 mg L−1 had adverse effects on certain physiological parameters, highlighting the need for careful consideration of the applied concentration of CeO2 NPs. Considering the response of essential oil compounds, combination of salinity stress and CeO2 treatments led to an increase in the concentrations of L-menthone, pulegone, and 1,8-cineole, which are the predominant compounds in spearmint essential oil. In summary, foliar application of CeO2 NPs strengthened the resilience of spearmint plants against salinity stress, offering new insights into the potential use of CeO2 NP treatments to enhance crop stress tolerance.

OsNAL11 and OsGASR9 Regulate the Low-Temperature Germination of Rice Seeds by Affecting GA Content

Low temperatures cause serious threat to rice seed emergence, which has become one of the main limiting factors in the production of direct seeding rice. It is of great importance to study the genes controlling low-temperature tolerance during seed germination and to mine the possible regulatory mechanism for developing new rice varieties with immense low-temperature germination ability. In the current research study, two types of mutants of nal11 and gasr9, derived from the WT (wild type) ZH11, were used for the analysis of low-temperature germinability. The results showed that the nal11 and gasr9 mutants displayed no significant difference in germination rate with ZH11 at room temperature, but the mutants showed significantly lower germination rates, germination potential and germination index, and slowed seedling growth in the simulated direct seeding experiments at low temperatures compared to ZH11. Additionally, the activity of POD, SOD, CAT, and anti-superoxide anion radial activity were significantly reduced, but the levels of MDA and H2O2 were significantly higher in the nal11 and gasr9 mutant seeds that were germinated at low temperatures compared to ZH11. Further analysis revealed that the levels of total active GA, especially GA4 and GA7, were significantly lower in the nal11 and gasr9 mutants than that in ZH11 during low-temperature germination. Based on qRT-PCR analysis, the expression levels of some GA synthesis-related genes were higher, whereas some were lower in the nal11 and gasr9 mutants than those in ZH11, however, the GA metabolism-related genes OsGA2ox8 and OsGA2ox10 and the GA signaling negative regulator gene SLR1 were significantly up-regulated in both nal11 and gasr9 mutants at several time points during low-temperature germination. This may explain the lower GA levels in the nal11 and gasr9 mutants. Furthermore, the interaction between the OsNAL11 and OsGASR9 proteins was confirmed by Y2H, LUC, and Co-IP assays. This study provides preliminary insights into the regulatory mechanism of the OsNAL11 and OsGASR9 genes, which control the low-temperature germination of rice seeds by affecting the GA pathway. Our study will provide the basis for further mining the molecular mechanisms of low-temperature germination in rice and valuable theoretical reference for breeding varieties with strong low-temperature germinability.

A highly permeable nanoplatform based on functionalized carbon dots for synergistic reactive oxygen/nitrogen species tumor therapy

Reactive oxygen species (ROS)-based antitumor strategies, particularly chemodynamic therapy, have garnered considerable attention. However, challenges such as difficulties in achieving deep penetration, relatively low H2O2 levels in the tumor microenvironment, the requirement for low pH by the Fenton reaction, and their short lifespan have impeded satisfactory therapeutic outcomes. Hence, we have developed a nanoplatform with enhanced permeability that not only generates significant amounts of ROS but also converts them into longer-lasting reactive nitrogen species (RNS), thereby improving tumor therapy efficacy. In our study, carbon dots were functionalized by doping with gold atoms and grafting nitrosoglutathione (GSNO) to form ACN, which exhibits glucose oxidase-like properties and enables laser-responsive NO release. ACN and indocyanine green (ICG) were then loaded onto MnO2 nanoflowers to form MnO2@AI. Upon arrival at the tumor site, MnO2 reacts with H2O2 and GSH, leading to its degradation and the subsequent release of ACN, which is characterized by three permeation-promoting properties: ultra-small size, positive charge, and NO content. In addition, ACN promotes H2O2 production through glucose metabolism and reduces pH, both of which enhance the Fenton-like reaction of MnO2, thereby amplifying ROS generation. The ICG in MnO2@AI enhances its photothermal properties, leading to the responsive release of NO from GSNO grafted onto ACN, which then reacts with the increased ROS to generate more toxic RNS. Collectively, the approach described herein offers substantial potential for advancing the treatment of malignant tumors.