Antioxidant Enzyme Activities Research Articles

Metabolomics and transcriptomics combined with physiology reveal key metabolic pathway responses in tobacco roots exposed to NaHS

Hydrogen sulfide (H2S) has emerged as a novel endogenous gas signaling molecule, joining the ranks of nitric oxide (NO) and carbon monoxide (CO). Recent research has highlighted its involvement in various physiological processes, such as promoting root organogenesis, regulating stomatal movement and photosynthesis, and enhancing plant growth, development, and stress resistance. Tobacco, a significant cash crop crucial for farmers’ economic income, relies heavily on root development to affect leaf growth, disease resistance, chemical composition, and yield. Despite its importance, there remains a scarcity of studies investigating the role of H2S in promoting tobacco growth. This study exposed tobacco seedlings to different concentrations of NaHS (an exogenous H2S donor) − 0, 200, 400, 600, and 800 mg/L. Results indicated a positive correlation between NaHS concentration and root length, wet weight, root activity, and antioxidant enzymatic activities (CAT, SOD, and POD) in tobacco roots. Transcriptomic and metabolomic analyses revealed that treatment with 600 mg/L NaHS significantly effected 162 key genes, 44 key enzymes, and two metabolic pathways (brassinosteroid synthesis and aspartate biosynthesis) in tobacco seedlings. The addition of exogenous NaHS not only promoted tobacco root development but also potentially reduced pesticide usage, contributing to a more sustainable ecological environment. Overall, this study sheds light on the primary metabolic pathways involved in tobacco root response to NaHS, offering new genetic insights for future investigations into plant root development.

Response Mechanism of Extracellular Polymeric Substances Synthesized by Alternaria sp. on Drought Stress in Alfalfa (Medicago sativa L.).

This study investigates how extracellular polymeric substances (EPS) synthesized by dark septate endophytic (DSE) improve alfalfa's drought resistance. Drought stress was simulated in hydroponic culture, and roots were treated with different EPS concentrations to determine their effects on drought tolerance and applicable concentrations. Hydroponic solutions with 0.25 and 0.50% EPS concentrations alleviated leaf wilting and increased total plant fresh weight by 35.8 and 57.7%, respectively. SEM shows that EPS attached to the roots and may have served to protect the root system. EPS treatment significantly depressed the MDA contents of the roots, stems, and leaves. Roots responded to drought stress by increasing soluble sugar contents and antioxidant enzyme activities, while mitigating stem and leaf stress by synthesizing lipid compounds, amino acids, and organic acid metabolites. Five metabolites in the stem have been reported to be associated with plant stress tolerance and growth, namely 3-O-methyl 5-O-(2-methyl propyl) (4S)-2,6-dimethyl-4-(2-nitrophenyl)-3,4-dihydropyridine-3,5-dicarboxylate, malic acid, PA (20:1(11Z)/15:0), N-methyl-4,6,7-trihydroxy-1,2,3,4-tetrahydroisoquinoline, and 2-(S-glutathionyl) acetyl glutathione. In summary, EPS treatment induced oxidative stress and altered plant metabolism, and this in turn increased plant antioxidant capacity. The results provide a theoretical basis for the application of EPS in commercial products that increase plant resistance and ecological restoration.

Optimized medium composition in Physalis alkekengi callus culture altered nitric oxide level for inducing antioxidant enzyme activities and secondary metabolites

Physalis alkekengi L. is a valuable medicinal plant from the Solanaceae family and has multiple therapeutic applications. This study aimed to develop an optimized protocol for callogenesis in P. alkekengi to obtain friable calluses with high biomass. The effect of different concentrations of picloram, casein hydrolysate (CH), basal media (Murashige and Skoog (MS) and Gamborg (B5)), and static magnetic field (SMF) were investigated on the callus induction and growth, signaling molecules, and enzymatic and non-enzymatic antioxidants. Results showed that CH (200 mgL−1) and SMF4 mT for 90 min increased callus induction and fresh weight in P. alkekengi, while different concentrations of picloram reduced callogenesis. Hypocotyl explants showed various callogenesis and metabolic responses depending on the basal medium type. The 2B5 medium supplied with CH 200 (mgL−1) induced friable and cream calluses with high biomass (0.62 g) compared to the MS medium (control). The maximum activity of superoxide dismutase and catalase activities was identified in the 2B5 medium and peroxidase in the 2MS medium. The highest total phenolic (129.44 µg g−1DW) content and phenylalanine-ammonia lyase activity were obtained in the 2MS medium, and total withanolides (49.86 µg g-1DW) and DPPH radical scavenging activity were observed in the 2B5 medium. The 2MS medium boosted the hydrogen peroxide and nitric oxide levels, while their contents alleviated in the 2B5 medium, although these parameters were higher than the control. The findings of this study suggest that an effective protocol for successful callogenesis in P. alkekengi and the nutrient composition of culture medium by affecting the level of signaling molecules can control the antioxidant defense system and callus growth.

Effects of High Salinity and Water Stress on Wetland Grasses from the Spanish Mediterranean Coast

The impacts of climate change are reaching unprecedented levels, heightening the risk of species loss and ecosystem service degradation. Wetlands, highly threatened ecosystems, serve vital ecological functions by capturing carbon, filtering water, and harbouring diverse wildlife. Coastal wetlands encounter many challenges, such as increased drought periods and escalating salinity levels, severely impacting plant biodiversity. Assessing how plants respond to various environmental stress factors is imperative for devising successful conservation strategies. In the present study, we examined three representative grass species found in various habitats within the Albufera Natural Park, close to the city of Valencia on the Spanish Mediterranean coast: Imperata cylindrica, Phragmites australis, and Saccharum ravennae. High salinity and water stress conditions were induced by subjecting the plants to irrigation with solutions containing 200, 400, 600, and 800 mM NaCl or withholding irrigation altogether to mimic coastal flooding and drought scenarios. The treatments were maintained until noticeable wilting of the plants occurred, at which point a range of stress biomarkers were determined, including photosynthetic pigments, ions, osmolytes, oxidative stress markers, and antioxidant metabolites, as well as antioxidant enzyme activities. Saccharum ravennae displayed the highest sensitivity to salt stress, whereas I. cylindrica appeared to be the most tolerant. The primary salinity tolerance mechanism observed in I. cylindrica and P. australis was a blockage of ion transport from the root zone to the aerial part, together with the salt-induced accumulation of proline and soluble sugars to high concentrations in the former. No significant effects of the water deficit treatment on the growth or biochemical parameters were observed for any of the analysed species. These findings offer valuable information for the effective management and conservation of coastal wetlands facing the challenges posed by climate change.

Release kinetic study of microplastics from N95 face masks and consequent effects on freshwater alga Scenedesmus obliquus

The uncontrolled disposal of N95 face masks, widely used during the recent COVID-19 pandemic can release significant amounts of microplastics and other additives into aquatic bodies. This study aimed to: (i) to quantify and analyze the released microplastics and heavy metals from N95 face masks weathered for various time periods (24, 48, 72, 96, 120, and 144 h) and (ii) to assess the cytotoxicity potential of the leachates on a model organism, freshwater alga Scenedesmus obliquus. The mask leachates contained microplastics, polypropylene in different shapes and sizes, and heavy metals like Cu, Cd, and Zn. The leachates significantly reduced cell viability and increased reactive oxygen species (ROS) generation, antioxidant enzyme activity, and membrane damage. The effects were also accompanied by a significant drop in the photosynthetic yield. All of the examined parameters indicated a dose-response relationship, with longer leaching periods resulting in higher microplastic concentrations. Mask leachates severely damaged the structural integrity of the algal cells, as seen in scanning electron microscopy images. The findings of our study confirm that the releases from disposable N95 face masks pose a severe threat to freshwater microalgae, and the cascading effects would harm the aquatic ecosystems.

Methane-rich saline ameliorates depressive-like behaviors during chronic unpredictable mild stress (CUMS).

Depression, considered the most prevalent neuropsychiatric disorder, is multifactorial and complex. Oxidative stress and inflammation significantly contribute to its etiology. Conversely, methane, a novel therapeutic gas, has demonstrated efficacy in enhancing tissue resilience against ischemic injuries and inflammation. In this study, we investigated the effect of methane-rich saline (MRS) on depression using the chronic unpredictable mild stress (CUMS) model. Depressed rats received MRS treatment, and depression-like behaviors and cognitive function were assessed through sucrose preference, open field, forced swimming, and Morris water maze tests. Additionally, we measured serum corticosterone levels, antioxidant enzyme activity, hippocampal malondialdehyde (MDA), and TNFα levels, and investigated histological changes in the hippocampus. Our findings revealed that MRS significantly ameliorated Depressive-like behaviors and cognitive impairment. Furthermore, MRS administration regulated serum corticosterone levels and also MRS reduced hippocampal lipid peroxidation, TNFα, and hippocampus tissue damage. MRS likely exerts its effects by reducing oxidative stress and inflammatory factors and modulating the function of the hypothalamus-pituitary-adrenal (HPA) axis. These results demonstrate the protective effects of MRS on the hippocampus in CUMS animals.

CuO nanoparticles elicit intestinal immunotoxicity in zebrafish based on intestinal microbiota dysbiosis.

Copper II oxide nanoparticles (CuO NPs), a kind of widely used nanomaterial, have been detected in food and the environment, which has aroused widespread public concern. Recently, increasing data have suggested that intestinal microecology is closely related to immune homeostasis. However, the intestinal immunotoxicity induced by CuO NPs through intestinal microbiota is still unknown. Therefore, in this study, zebrafish were exposed to CuO NPs to explore intestinal immunotoxicity by evaluating physiological indicators, intestinal tissue injury, antioxidant enzyme activities, gene expression of immune factors, and changes in intestinal microbiota and its metabolites (short-chain fatty acids (SCFAs) and lipopolysaccharides (LPS)). The results revealed that the intestinal immunotoxicity of CuO NPs was mediated by the impact on intestinal microbiota and its metabolite levels. Specifically, changes were observed in the abundance of microbes that participated in the metabolism of SCFAs and LPS. The reduction in acetic acid, propionic acid and valeric acid upregulated GPR84 expression, and the decline in LPS levels further resulted in the suppression of the key immune regulatory pathways TLR4/MyD88/NF-κB, ultimately leading to intestinal immunotoxicity. This study would provide a scientific basis for the risk assessment of CuO NPs and a new perspective for research on the immunotoxicity of nanoparticles.

Synergistic effects of SlCBF1 and ethylene signaling on the maintenance of tomatoes quality during long-term cold storage

Refrigeration is commonly employed for postharvest storage of fruit and vegetable; however, its usage can increase the risk of chilling injury (CI). C-repeat/dehydration-responsive element binding factors (CBFs) have been identified in various plants. However, the significance of CBFs in preserving fruit quality during cold storage remains understudied, particularly in transgenic fruit. In this study, we demonstrate that the mutation of SlCBF1 gene worsen CI symptoms in tomatoes, hinder cold-induced ethylene production, and influence the expression of genes associated with ethylene signaling. Notably, our correlation analysis reveals that the severity of CI is partially correlated with ethylene production. Additionally, blocking ethylene action using 1-methylcyclopropene (1-MCP), decrease the cold resistance of tomatoes. Knocking out SlCBF1 gene impact the effect of 1-MCP-inhibited cold responses, including the suppression of antioxidant enzymes activities. These findings underscore positive regulation of cold resistance in postharvest tomatoes by SlCBF1 in collaboration with ethylene signaling.

A Study on the Functional Identification of Overexpressing Winter Wheat Expansin Gene TaEXPA7-B in Rice under Salt Stress

Expansin is a cell wall relaxant protein that is common in plants and directly or indirectly participates in the whole process of plant root growth, development and morphogenesis. A well-developed root system helps plants to better absorb water and nutrients from the soil while effectively assisting them in resisting osmotic stress, such as salt stress. In this study, we observed and quantified the morphology of the roots of Arabidopsis overexpressing the TaEXPAs gene obtained by the research group in the early stage of development. We combined the bioinformatics analysis results relating to EXPA genes in five plants and identified TaEXPA7-B, a member of the EXPA family closely related to root development in winter wheat. Subcellular localization analysis of the TaEXPA7-B protein showed that it is located in the plant cell wall. In this study, the TaEXPA7-B gene was overexpressed in rice. The results showed that plant height, root length and the number of lateral roots of rice overexpressing the TaEXPA7-B gene were significantly higher than those of the wild type, and the expression of the TaEXPA7-B gene significantly promoted the growth of lateral root primordium and cortical cells. The plants were treated with 250 mM NaCl solution to simulate salt stress. The results showed that the accumulation of osmotic regulators, cell wall-related substances and the antioxidant enzyme activities of the overexpressed plants were higher than those of the wild type, and they had better salt tolerance. This paper discusses the effects of winter wheat expansins in plant root development and salt stress tolerance and provides a theoretical basis and relevant reference for screening high-quality expansin regulating root development and salt stress resistance in winter wheat and its application in crop molecular breeding.

Tenuazonic acid mycotoxicosis in an immunosuppressed mouse model and evaluation of the protective effect of cinnamaldehyde against tenuazonic acid mycotoxicosis

Patients with impaired immune systems are particularly vulnerable to infections. With the increasing number of immunocompromised patients, it becomes necessary to design studies that evaluate the effects of toxic contaminants that are a part of our daily lives. Simultaneously, the management of these toxic components also becomes essential. Therefore, the present study evaluated the possible protective role of Cinnamaldehyde (Cin) against tenuazonic acid-induced mycotoxicosis in the immunosuppressed murine model. Tenuazonic acid (TeA), a toxin usually produced by Alternaria species, is a common contaminant in tomato and tomato-based products. Evaluating the potential toxicity of a hazardous chemical necessitates the use of in vitro, in vivo, and in silico methods. Here, the immunomodulatory effect of TeA was assessed in vitro using mouse splenocytes. In silico docking was carried out for the tumour markers of eight organs and TeA. The haematological, histopathological, and biochemical aspects were analysed in vivo. The sub-chronic intoxication of mice with TeA showed elevated malondialdehyde, reduced catalase, and superoxide dismutase production, as well as abnormal levels of aspartate aminotransferase and alanine transaminase. The treatment with Cin prevented TeA-induced alterations of antioxidant defense enzyme activities and significantly forbade TeA-induced organ damage, showing therapeutic effects and toxicity reduction in TeA-induced mycotoxicosis.

In vivo evaluation by oral administration of chitosan combined with bioactive glass against cadmium-induced toxicity in rats

Bioactive glass and chitosan are biomaterials widely used for orthopedic applications, notably as bone grafts. Although these biomaterials show promising therapeutic properties, no research has yet examined their potential for oral administration in soft tissue protection, particularly against metal toxicity. The aim of our study was to evaluate the potential of chitosan from cuttlefish (CHS) bone combined with bioactive glass (BG) against Cadmium-induced toxicity in rats. Cadmium (Cd), a heavy metal that accumulates in tissues, causes various disorders. Experiments were carried out on rats intoxicated acutely by oral administration of Cd (20 mg/kg body weight) and/or concomitantly with oral administration of CHS/BG (100 mg/kg body weight) for 7 days. Using pathophysiological and biochemical tests, we evaluated the detoxifying effect of orally administered CHS/BG against Cd toxicity. Our results showed, for the first time, a significant detoxifying effect of CHS/BG against Cd-induced toxicity in rats. Treatment with CHS/BG protected rats against the harmful effects of Cd by reducing lipid peroxidation levels and enhancing antioxidant enzyme activities. In addition, it helped restore phosphocalcic balance and protect liver, kidney and brain function. Remarkably, it also reduced Cd levels in the liver, kidneys and brain, as well as in the bones of rats. These results show that oral administration of CHS/BG has a strong therapeutic potential on tissues through detoxification of cadmium-exposed rats.

Norgestrel causes oxidative damage to the digestive gland of the clam Mactra veneriformis

Increasingly, progestins are being detected in aquatic environments, especially in aquaculture areas, and concern about their adverse effects on aquatic organisms is growing. However, the mechanisms underlying progestin-induced oxidative stress and the antioxidant response of aquatic invertebrates to progestin exposure are unknown. Researchers recently reported that norgestrel (NGT) likely causes oxidative stress in the clam Mactra veneriformis. In this study, we assessed reactive oxygen species (ROS) levels, antioxidant enzyme activity, malonaldehyde content, ultrastructure, and DNA damage in the digestive gland of M. veneriformis exposed to 7.69 or 756.62 ng/L of NGT for 21 days. We also conducted tandem mass tag-based quantitative proteomic analysis to detect the protein response and gain insights into response mechanisms in clams exposed to NGT. We found that NGT enhanced oxidative phosphorylation via the wingless/integrated signaling pathway and triggered ROS generation. The alterations of antioxidant enzyme activities suggested that these enzymes are involved in scavenging NGT-induced ROS. NGT weakened antioxidant defense by suppressing the antioxidant synthesis-related AMP-activated protein kinase/forkhead box O and sirtuin 1/forkhead box O pathways. Additionally, cell membrane dissolution, mitochondrial cristae rupture, DNA damage, elevation of malonaldehyde content, and oxidation of lipid, protein, and glucose occurred due to compromised redox homeostasis. Our results highlight the oxidative stress, antioxidant response, and oxidative damage induced by NGT in M. veneriformis and shed light on ecological risks of progestins to aquatic invertebrates.

Mitigating Ni and Cu ecotoxicity in the ecological restoration material and ornamental Primula forbesii Franch. with exogenous 24-epibrassinolide and melatonin

Nickel (Ni) and copper (Cu) contamination have become major threats to plant survival worldwide. 24-epibrassinolide (24-EBR) and melatonin (MT) have emerged as valuable treatments to alleviate heavy metal-induced phytotoxicity. However, plants have not fully demonstrated the potential mechanisms by which these two hormones act under Ni and Cu stress. Herein, this study investigated the impact of individual and combined application of 24-EBR and MT on the growth and physiological traits of Primula forbesii Franch. subjected to stress (200 μmol L–1 Ni and Cu). The experiments compared the effects of different mitigation treatments on heavy metal (HM) stress and the scientific basis and practical reference for using these exogenous substances to improve HM resistance of P. forbesii in polluted environments. Nickel and Cu stress significantly hindered leaf photosynthesis and nutrient uptake, reducing plant growth and gas exchange. However, 24-EBR, MT, and 24-EBR + MT treatments alleviated the growth inhibition caused by Ni and Cu stress, improved the growth indexes of P. forbesii, and increased the gas exchange parameters. Exogenous MT effectively alleviated Ni stress, and 24-EBR + MT significantly alleviated the toxic effects of Cu stress. Unlike HM stress, MT and 24-EBR + MT activated the antioxidant enzyme activity (by increasing superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), significantly reduced reactive oxygen species (ROS) accumulation, and regulated ascorbate and glutathione cycle (AsA-GSH) efficiency. Besides, the treatments enhanced the ability of P. forbesii to accumulate HMs, shielding plants from harm. These findings conclusively illustrate the capability of 24-EBR and MT to significantly bolster the tolerance of P. forbesii to Ni and Cu stress.

Unmasking Spatial Heterogeneity in Phytotoxicology Mechanisms Induced by Carbamazepine by Mass Spectrometry Imaging and Multiomics Analyses.

Previous studies have highlighted the toxicity of pharmaceuticals and personal care products (PPCPs) in plants, yet understanding their spatial distribution within plant tissues and specific toxic effects remains limited. This study investigates the spatial-specific toxic effects of carbamazepine (CBZ), a prevalent PPCP, in plants. Utilizing desorption electrospray ionization mass spectrometry imaging (DESI-MSI), CBZ and its transformation products were observed predominantly at the leaf edges, with 2.3-fold higher concentrations than inner regions, which was confirmed by LC-MS. Transcriptomic and metabolic analyses revealed significant differences in gene expression and metabolite levels between the inner and outer leaf regions, emphasizing the spatial location's role in CBZ response. Notably, photosynthesis-related genes were markedly downregulated, and photosynthetic efficiency was reduced at leaf edges. Additionally, elevated oxidative stress at leaf edges was indicated by higher antioxidant enzyme activity, cell membrane impairment, and increased free fatty acids. Given the increased oxidative stress at the leaf margins, the study suggests using in situ Raman spectroscopy for early detection of CBZ-induced damage by monitoring reactive oxygen species levels. These findings provide crucial insights into the spatial toxicological mechanisms of CBZ in plants, forming a basis for future spatial toxicology research of PPCPs.

Enhancing drought tolerance in Malva parviflora plants through metabolic and genetic modulation using Beauveria bassiana inoculation

BackgroundEnhancing crops’ drought resilience is necessary to maintain productivity levels. Plants interact synergistically with microorganisms like Beauveria bassiana to improve drought tolerance. Therefore, the current study investigates the effects of biopriming with B. bassiana on drought tolerance in Malva parviflora plants grown under regular irrigation (90% water holding capacity (WHC)), mild (60% WHC), and severe drought stress (30% WHC).ResultsThe results showed that drought stress reduced the growth and physiological attributes of M. parviflora. However, those bioprimed with B. bassiana showed higher drought tolerance and enhanced growth, physiological, and biochemical parameters: drought stress enriched malondialdehyde and H2O2 contents. Conversely, exposure to B. bassiana reduced stress markers and significantly increased proline and ascorbic acid content under severe drought stress; it enhanced gibberellic acid and reduced ethylene. Bioprimed M. parviflora, under drought conditions, improved antioxidant enzymatic activity and the plant’s nutritional status. Besides, ten Inter-Simple Sequence Repeat primers detected a 25% genetic variation between treatments. Genomic DNA template stability (GTS) decreased slightly and was more noticeable in response to drought stress; however, for drought-stressed plants, biopriming with B. bassiana retained the GTS.ConclusionUnder drought conditions, biopriming with B. bassiana enhanced Malva’s growth and nutritional value. This could attenuate photosynthetic alterations, up-regulate secondary metabolites, activate the antioxidant system, and maintain genome integrity.

Beneficial role of Coronatine on the morphological and physiological responses of Cress Plants (Lepidium sativum) exposed to Silver Nanoparticle

BackgroundSilver nanoparticles are widely used in various fields such as industry, medicine, biotechnology, and agriculture. However, the inevitable release of these nanoparticles into the environment poses potential risks to ecosystems and may affect plant productivity. Coronatine is one of the newly identified compounds known for its beneficial influence on enhancing plant resilience against various stress factors. To evaluate the effectiveness of coronatine pretreatment in mitigating the stress induced by silver nanoparticles on cress plants, the present study was carried out.ResultsOur findings indicated a decrease in multiple growth parameters, proline content, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids in cress plants exposed to silver nanoparticle treatment. This decline could be attributed to the oxidative stress induced by the presence of silver nanoparticles in the plants. Conversely, when coronatine treatment was applied, it effectively mitigated the reduction in growth parameters and pigments induced by the silver nanoparticles. Furthermore, we observed an increase in silver content in both the roots and shoot portions, along with elevated levels of malondialdehyde (MDA) content, hydrogen peroxide (H2O2), anthocyanins, glutathione (GSH), and antioxidant enzyme activities in plants exposed to silver nanoparticles. Concurrently, there was a decrease in total phenolic compounds, ascorbate, anthocyanins, and proline content. Pre-treatment of cress seeds with coronatine resulted in increased levels of GSH, total phenolic compounds, and proline content while reducing the silver content in both the root and shoot parts of the plant.ConclusionsCoronatine pre-treatment appeared to enhance both enzymatic and non-enzymatic antioxidant activities, thereby alleviating oxidative stress and improving the response to stress induced by silver nanoparticles.

Unravelling drought and salinity stress responses in barley genotypes: physiological, biochemical, and molecular insights

In the face of escalating environmental challenges, understanding crop responses to abiotic stress is pivotal for sustainable agriculture. The present study meticulously investigates the intricate interplay between drought and salinity stress in barley (Hordeum vulgare L.). Employing three distinct barley genotypes—Traveller, Prunella, and Zahna—we scrutinize their physiological, biochemical, and molecular adaptations under stress conditions. Our findings underscore genotype-specific responses, unravelling the multifaceted mechanisms that govern stress tolerance. Chlorophyll content, a vital indicator of photosynthetic efficiency, exhibits significant variations across genotypes. Salinity stress induces a decline in chlorophyll levels, while drought stress triggers a more nuanced response. Stomatal conductance, a key regulator of water loss, also diverges among the genotypes. Traveller displays remarkable stomatal closure under drought, conserving water, whereas Prunella and Zahna exhibit contrasting patterns. Antioxidant enzyme activities, crucial for combating oxidative stress, fluctuate significantly. Activities of superoxide dismutase (SOD) and catalase (CAT) surge under salinity stress, while drought predominantly impacts SOD. Gene expression profiling reveals genotype-specific signatures, with stress-responsive genes modulating adaptive pathways. Correlation analyses revealed the intricate interplay of the physiological and biochemical parameters. Genotype-specific adaptations, coupled with dynamic physiological and molecular responses, underscore the plasticity of barley’s stress tolerance mechanisms. Throughout the study, the Zahna genotype demonstrated notable tolerance in terms of performance. These insights hold promise for breeding resilient cultivars, bolstering food security in an increasingly unpredictable climate. By deciphering the barley stress symphony, we contribute to the harmonious orchestration of sustainable agricultural practices.

Potential of the plant growth-promoting rhizobacterium Rhodococcus qingshengii LMR356 in mitigating lead stress impact on Sulla spinosissima L.

Mining-related lead (Pb) pollution of the soil poses serious hazards to ecosystems and living organisms, including humans. Improved heavy metal phytoremediation efficacy, achieved by using phytostabilizing plants assisted by plant-growth-promoting (PGP) microorganisms, has been presented as an effective strategy for remediating polluted soils. The objective of this research was to examine the response and potential of the plant-growth-promoting bacterium LMR356, a Rhodococcus qingshengii strain isolated from an abandoned mining soil, under lead stress conditions. Compared to non-contaminated culture media, the presence of lead induced a significant decrease in auxin production (from 21.17 to 2.65 μg mL-1) and phosphate solubilization (from 33.60 to 8.22 mg L-1), whereas other PGP traits increased drastically, such as 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity (from 38.17 to 71.37 nmol mg-1 h-1 α-ketobutyrate), siderophore production (from 69 to 83%), exopolysaccharide production (from 1952.28 to 3637.72 mg mL-1), biofilm formation, and motility. We, therefore, investigated the behavior of Sulla spinosissima L. in the presence or absence of this strain under a variety of experimental conditions. Under hydroponic conditions, Sulla plants showed endurance to varying lead concentrations (500-1000 μM). Inoculation of plants with Rhodococcus qingshengii strain LMR356 enhanced plant tolerance, as demonstrated by the increase in plant biomass (ranging from 14.41 to 79.12%) compared to non-inoculated Pb-stressed and non-stressed control plants. Antioxidant enzyme activities (increasing by -42.71 to 126.8%) and chlorophyll (383.33%) and carotenoid (613.04%) content were also augmented. In addition to its impact on plant lead tolerance, strain LMR356 showed a growth-promoting effect on Sulla plants when cultivated in sterilized non-contaminated sand. Parameters such as plant biomass (16.57%), chlorophyll (24.14%), and carotenoid (30%) contents, as well as ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT) activities, were all elevated compared to non-inoculated plants. Furthermore, when the same plant species was cultivated in highly polluted soil, inoculation increased plant biomass and improved its physiological properties. These findings demonstrate that LMR356 is a phytobeneficial bacterial strain capable of enhancing Sulla growth under normal conditions and improving its heavy metal tolerance in multi-polluted soils. Thus, it can be considered a promising biofertilizer candidate for growing Sulla spinosissima L. or other selected plants intended for application in restoration and stabilization initiatives aimed at reviving and safeguarding environmentally compromised and polluted soils after mining activities.

Antioxidant enzyme activities and markers of oxidative stress in the life cycle of different Earthworm species

Antioxidant enzyme activities and markers of oxidative stress in the life cycle of different Earthworm species

Circadian rhythms of antioxidant enzymes activity, clock, and inflammation factors are disrupted in the prefrontal cortex of aged rats. Potential targets for therapeutic strategies for a healthy aging.

Age impairs cognitive functions and antioxidant defenses, for example, by increasing oxidative stress and inflammation in the brain. However, so far, there is no report on the consequences of aging on temporal patterns of proteins and lipids oxidation, antioxidant enzymes activity, endogenous clock and proinflammatory cytokine, in the prefrontal cortex (PFC). Therefore, our objectives here were: 1) to investigate the endogenous nature of 24h-rhythms of lipoperoxidation, protein carbonyls levels, CAT and GPx activity, RORa, and TNFα, in the rat PFC, and 2) to study the consequences of aging on the circadian organization of those factors in the same brain area. To do that, 3- and 22-mo-old male Holtzman rats were maintained under constant darkness conditions during 15 days before reaching the corresponding age. PFC samples were isolated every 4 h, under dim-red light, during a 24h period. Our results revealed circadian patterns of antioxidant enzymes activity, oxidative stress, RORa and TNFα proteins levels, in the PFC of young rats. The circadian distribution of the rhythms’ phases suggests the existence of a reciprocal communication among the antioxidant defenses, the endogenous clock, and the inflammation, in the PFC. Noteworthy, such circadian organization disappears in the PFC of aged rats. An increased oxidative stress would make the redox environment to change into an oxidative status, which alters the endogenous clock activity and disrupts the circadian organization of, at least part, of the antioxidant defenses and the TNFα, in the PFC. These results might highlight novel chronobiological targets for the design of therapeutic strategies addressed to a healthy aging.