Peroxidase Enzyme Research Articles

Human and camel cystic echinococcosis – a polyclonal antibody-based sandwich ELISA for its serodiagnosis with molecular identification

Cystic echinococcosis (CE) is an emergent neglected disease affecting human and animals in Egypt with a wide distribution and incidence. This study aimed to evaluate the use of a polyclonal antibody-based sandwich ELISA in the detection of Echinococcus granulosus antigen in human and camel sera. Hydatid cyst protoscoleces antigen (PsAg) was isolated from hydatid cysts collected from naturally infected camel livers and lungs. PsAg was used for immunization of rabbits to raise IgG polyclonal antibodies (IgG PsAb). IgG PsAb were then precipitated, purified using Protein-A Sepharose gel and labeled with horseradish peroxidase enzyme. We assayed the purity of the IgG PsAb, and the two prepared E. granulosus antigens CPsAg from camel cysts and HPsAg from human cysts by Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The resulted protein bands of the prepared CPsAg appeared at different molecular weights: 180, 90, 68, 54, 42 and 22 kDa while, HPsAg shared with it in 4 common bands at 68, 54, 42, and 22 kDa. The purified IgG PsAb had been resolved at two bands at 52 kDa and at 32 kDa. Sandwich ELISA were performed for the detection of circulating E. granulosus antigens in sera of human (n = 183) and camels (n = 190). The purified IgG PsAb showed strong reactivity against E. granulosus infected human and camel samples and no cross reactivity neither with free-healthy negative sera nor with others parasitic diseases (Schistosomiasis, Fascioliasis, Toxoplasmosis, Ancylostomiasis for human samples and Fascioliasis, ticks’ infestation, Eimeriosis, Cryptosporidiosis, Nasal myiasis, Toxoplasmosis for camel samples). The sensitivity of the assay was 98.25% (56/57) and 96.9% (31/32) against human and camel samples, respectively. Specificity was 100% in both human and camel samples. Sandwich ELISA detected CE in 33.3% (24/72) and 55.6% (50/90) random human and camel samples, respectively. Indirect ELISA, using CPsAg, was used for detection of antibodies in positive human and camels’ sera and detected 96.5% (55/57) and 93.8% (30/32) of human and camel samples, respectively. In our study, Genomic DNA was extracted from protoscoleces fluid of human liver hydatid cysts to identify the Echinococcus sp. isolate based on NADH dehydrogenase subunit 1 (NAD1) gene by Polymerase Chain Reaction (PCR) and the isolate (GenBank: OP785689.1) were identified as E. granulosus sensu lato genotype. In conclusion, Sandwich ELISA technique was found to be a potent and sensitive assay for detection of hydatid antigen in both human and camel samples.

Evaluation of Biocontrol-based Formulations against Late Leaf Spot and Rust in Groundnut

This study investigated the efficacy of various biocontrol-based formulations against late leaf spot (LLS) (Phaeoisariopsis personata) and rust (Puccinia arachidis) in groundnut. Pot culture and field experiments were conducted during the Kharif season (June-September) of 2022. Disease incidence of both late leaf spot and rust was significantly lower in groundnut plants treated with a combination of biocontrol-based formulations compared to control. The most effective eco-friendly treatment included a combination of Trichoderma asperellum, Pseudomonas fluorescens, fortified lignite fly ash and Annamalai mixture. This combination significantly reduced lesion frequency and Percent Disease Index (PDI) for both diseases at 50, 70 and 90 DAS, compared to other treatments. The combination of biocontrol-based formulations also significantly increased the pod yield. Furthermore, the same treatment increased the induction of defense enzymes peroxidase (2.22 fold), polyphenol oxidase (1.28 fold) and phenylalanine ammonia-lyase (6.25 fold). While Carbendazim effectively reduced disease incidence, it was surpassed by the biocontrol-based module in terms of both disease control and yield. These findings suggest that biocontrol-based formulations can be a sustainable approach for managing LLS and rust diseases in groundnut cultivation.

Efficacy of Using Chemical Inducers and Biological Agents to Control Strawberry Leaf Spot Disease on Chemical Components and Enzyme Activity

Strawberry plants are subjected to many pathogens. Fungal diseases of strawberries are important worldwide and occur in all parts of the plant, including leaves, crowns, and fruits. The results of the bio-agent experiment indicated that Trichoderma harzianum was the most effective in reducing the growth of Alternaria alternata and Botrytis cinerea in vitro, the main causes of leaf spots in strawberry plants. The inhibition zone was observed and mycelium of T. harzianum invaded the colony of the tested pathogens. The importance of the biochemical study of defense reaction in the physiology of disease resistance was accepted. The activity of total, free, and conjugated phenols as well as peroxidase, polyphenol oxidase, and catalase enzyme activities were determined in resistant and susceptible strawberry cultivars. All the total, free, and conjugated phenols increased in resistant cultivars (Fortuna and Winter Star) and decreased in susceptible cultivar (Festival). Oxidative enzymes, like the increased activity of enzymes that appear mince of new polypeptide protein, have become models in the study of plant disease resistance. The higher content of peroxidase, polyphenol oxidase, and catalase enzymes in resistant cultivars, were noticed compared with those in susceptible ones. It was found also that, the chemical inducers increased total phenols in resistant and susceptible cultivars i.e., potassium di-phosphate, ferrous sulphate, and oxalic acid. Inducer resistance also caused an increase of free phenols than the control. However, conjugated phenols accumulated faster after using chemical inducers in the leaves of the resistant cultivars, than the susceptible ones.

Ameliorative effect of ferulic acid on thyroid dysfunction against propyl-thiouracil induced hypothyroid rats.

Hypothyroidism is an endocrine disorder characterised by decreased T3, T4 and increased TSH levels. This study aims to examine the potential effects of Ferulic acid (FA) on rats with hypothyroidism induced by propylthiouracil through the estimation of biochemical parameters and histopathological studies. Twenty-five female wistar rats were allocated into five groups: Control group [1% CMC, p.o.], Disease group [PTU-50 mg/kg, p.o.], [Levothyroxine (LT4) group - 20 µg/kg, p.o. + PTU-50 mg/kg, p.o.], [FA -25 mg/kg, p.o. + PTU-50 mg/kg, p.o.] and [FA 50 mg/kg, p.o. + PTU-50 mg/kg, p.o.]. On 15th day blood was collected and serum was separated for estimation of biochemical parameters, liver and kidney homogenate was utilised for the estimation of oxidative stress markers and the thyroid gland was dissected to examine histological features. PTU administration for 14 days showed a substantial decline in T3 and T4 and increases in TSH levels. PTU-administered rats significantly increased TC, TG and LDL levels, and decreased HDL levels. AST, ALT, urea, creatinine, and IL-6 were determined and these levels were significantly altered in PTU-induced hypothyroid group. In hypothyroid rats MDA, NO, GSH and SOD levels were significantly altered. However, treatment with FA for 14 days attenuated PTU-induced alterations. Furthermore, FA improves the histological changes of the thyroid gland. In conclusion, FA treatment showed a protective effect against hypothyroidism by stimulating the thyroid hormones through the activation of thyroid peroxidase enzyme and improving thyroid function. In addition, FA diminished the increase in lipids, liver and kidney markers, oxidative stress and inflammation.

Inactivation kinetics of polyphenol oxidase and peroxidase enzymes in buffer solutions by ultraviolet light sources at multiple UV-C wavelengths

This study aimed to evaluate the effect of multiple wavelengths of UV-C light sources on the inactivation of polyphenol oxidase (PPO) and peroxidase (POD) in buffer solutions. Enzyme solutions were treated with a UV-C excimer lamp (EL) emitting at 222 nm, low-pressure mercury (LPM) lamp at 253.7 nm, four UV-LEDs sources emitting at 255, 265, 275 and 285 nm, and a novel pulsed UV-C lamp (PL) emitting at 232, 242, 261 and 272 nm. Three kinetic models were used to compare UV-C wavelengths enzymatic inactivation efficacy considering the volume average fluence for 90% reduction (HD). Validation of kinetic parameters was performed under continuous-flow treatment in a UV-C LED and EL system. EL treatment resulted in the highest inactivation efficacy of PPO and POD enzymes with HD of 52.8 and 74.8 mJ/cm2, respectively. PL inactivation efficacy for both enzymes was higher than with LPM lamp or UV-LEDs. The two-component first-order model best described the inactivation of PPO and POD in a buffer solution. The adjusted kinetic parameters for this model were validated under UV-C light continuous flow processing. This study contributes to the development of liquid food treatment by ultraviolet technology.

Investigation of morpho-physiolgical traits and gene expression in barley under nitrogen deficiency

Nitrogen (N) is an essential element for plant growth, and its deficiency influences plants at several physiological and gene expression levels. Barley (Hordeum vulgare) is one of the most important food grains from the Poaceae family and one of the most important staple food crops. However, the seed yield is limited by a number of stresses, the most important of which is the insufficient use of N. Thus, there is a need to develop N-use effective cultivars. In this study, comparative physiological and molecular analyses were performed using leaf and root tissues from 10 locally grown barley cultivars. The expression levels of nitrate transporters, HvNRT2 genes, were analyzed in the leaf and root tissues of N-deficient (ND) treatments of barley cultivars after 7 and 14 days following ND treatment as compared to the normal condition. Based on the correlation between the traits, root length (RL) had a positive and highly significant correlation with fresh leaf weight (FLW) and ascorbate peroxidase (APX) concentration in roots, indicating a direct root and leaf relationship with the plant development under ND. From the physiological aspects, ND enhanced carotenoids, chlorophylls a/b (Chla/b), total chlorophyll (TCH), leaf antioxidant enzymes such as ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT), and root antioxidant enzymes (APX and POD) in the Sahra cultivar. The expression levels of HvNRT2.1, HvNRT2.2, and HvNRT2.4 genes were up-regulated under ND conditions. For the morphological traits, ND maintained root dry weight among the cultivars, except for Sahra. Among the studied cultivars, Sahra responded well to ND stress, making it a suitable candidate for barely improvement programs. These findings may help to better understand the mechanism of ND tolerance and thus lead to the development of cultivars with improved nitrogen use efficiency (NUE) in barley.

Graphene quantum dots on TiO2 nanotubes as a light-assisted peroxidase nanozyme

Hybrid nanozyme graphene quantum dots (GQDs) deposited TiO2 nanotubes (NTs) on titanium foil (Ti/TiO2 NTs-GQDs) were manufactured by bestowing the hybrid with the advantageous porous morphology, surface valence states, high surface area, and copious active sites. The peroxidase-like activity was investigated through the catalytic oxidation of chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2, which can be visualized by the eyes. TiO2 NTs and GQDs comprising oxygen-containing functional groups can oxidize TMB in the presence of H2O2 by mimicking peroxidase enzymes. The peroxidase-mimicking activity of hybrid nanozyme was significantly escalated by introducing light illumination due to the photosensitive features of the hybrid material. The peroxidase-like activity of Ti/TiO2 NTs-GQDs enabled H2O2 determination over the linear range of 7 to 250 μM, with a LOD of 2.1 µM. The satisfying peroxidase activity is possibly due to the unimpeded access of H2O2 to the catalyst’s active sites. The porous morphology provides the easy channeling of reactants and products. The periodic structure of the material also gave rise to acceptable reproducibility. Without material functionalization, the Ti/TiO2 NTs-GQDs can be a promising substitute for peroxidases for H2O2 detection.Graphical abstract

Antioxidant Responses and Growth Impairment in Cucurbita moschata Infected by Meloidogyne incognita.

Pumpkins (Cucurbita moschata), valued for their nutritional, medicinal, and economic significance, face threats from Meloidogyne incognita, a critical plant-parasitic nematode. This study extensively examines the impact of M. incognita on the growth, physiological, and biochemical responses of C. moschata. We demonstrate that M. incognita infection leads to significant growth impairment in C. moschata, evidenced by reduced plant height and biomass, along with the significant development of nematode-induced galls. Concurrently, a pronounced oxidative stress response was observed, characterized by elevated levels of hydrogen peroxide and a significant increase in antioxidant defense mechanisms, including the upregulation of key antioxidative enzymes (superoxide dismutase, glutathione reductase, catalase, and peroxidase) and the accumulation of glutathione. These responses highlight a dynamic interaction between the plant and the nematode, wherein C. moschata activates a robust antioxidant defense to mitigate the oxidative stress induced by nematode infection. Despite these defenses, the persistence of growth impairment underscores the challenge posed by M. incognita to the agricultural production of C. moschata. Our findings contribute to the understanding of plant-nematode interactions, paving the way for the development of strategies aimed at enhancing resistance in Cucurbitaceae crops against nematode pests, thus supporting sustainable agricultural practices.

Human mesenchymal stem cells derived exosomes improve ovarian function in chemotherapy-induced premature ovarian insufficiency mice by inhibiting ferroptosis through Nrf2/GPX4 pathway.

Chemotherapy exposure has become a main cause of premature ovarian insufficiency (POI). This study aimed to evaluate the role and molecular mechanism of human umbilical cord mesenchymal stem cell-derived exosomes (hUMSC-Exos) in ovarian function protection after chemotherapy. hUMSC-Exos were applied to cyclophosphamide-induced premature ovarian insufficiency mice and human ovarian granulosa tumor cells (KGN) to determine their effects on follicular development and granulosa cell apoptosis. Evaluation was done for iron ion and reactive oxygen species (ROS) production, lipid peroxidation levels, and changes in iron death-related molecules (nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Glutathione Peroxidase enzyme 4 (GPX4), and Solute carrier family 7 member 11 cystine glutamate transporter (SLC7A11; xCT)). Furthermore, rescue experiments using an Nrf2 inhibitor were performed to assess the therapeutic effects of hUMSC-Exos on granulosa cells. hUMSC-Exos promoted ovarian hormone levels and primary follicle development in POI mice and reduced granulosa cell apoptosis. After hUMSC-Exos treatment, the ROS production, free iron ions and lipid peroxidation levels of granulosa cells decreased, and the iron death marker proteins Nrf2, xCT and GPX4 also decreased. Furthermore, the Nrf2 inhibitor ML385 significantly attenuated the effects of hUMSC-Exos on granulosa cells. hUMSC-Exos inhibit ferroptosis and protect against CTX-induced ovarian damage and granulosa cell apoptosis through the Nrf2/GPX4 signaling pathway, revealing a novel mechanism of hUMSC-Exos in POI therapy.

Syagrus coronata fixed oil prevents rotenone-induced movement disorders and oxidative stress in Drosophila melanogaster

ABSTRACT One prominent aspect of Parkinson’s disease (PD) is the presence of elevated levels of free radicals, including reactive oxygen species (ROS). Syagrus coronata (S. coronata), a palm tree, exhibits antioxidant activity attributed to its phytochemical composition, containing fatty acids, polyphenols, and flavonoids. The aim of this investigation was to examine the potential neuroprotective effects of S. coronata fixed oil against rotenone-induced toxicity using Drosophila melanogaster. Young Drosophila specimens (3–4 d old) were exposed to a diet supplemented with rotenone (50 µM) for 7 d with and without the inclusion of S. coronata fixed oil (0.2 mg/g diet). Data demonstrated that rotenone exposure resulted in significant locomotor impairment and increased mortality rates in flies. Further, rotenone administration reduced total thiol levels but elevated lipid peroxidation, iron (Fe) levels, and nitric oxide (NO) levels while decreasing the reduced capacity of mitochondria. Concomitant administration of S. coronata exhibited a protective effect against rotenone, as evidenced by a return to control levels of Fe, NO, and total thiols, lowered lipid peroxidation levels, reversed locomotor impairment, and enhanced % cell viability. Molecular docking of the oil lipidic components with antioxidant enzymes showed strong binding affinity to superoxide dismutase (SOD) and glutathione peroxidase (GPX1) enzymes. Overall, treatment with S. coronata fixed oil was found to prevent rotenone-induced movement disorders and oxidative stress in Drosophila melanogaster.

Comparative Effect of Seed Coating and Biopriming of Bacillus aryabhattai Z-48 on Seedling Growth, Growth Promotion, and Suppression of Fusarium Wilt Disease of Tomato Plants.

Beneficial plant microbes can enhance the growth and quality of field crops. However, the benefits of microbes using cheap and efficient inoculation methods are still uncommon. Seed coating with biocontrol agents can reduce the amount of inocula along with having the potential for large-scale application. Hence, in this research work, the comparative potential of tomato seed coating and biopriming with Bacillus aryabhattai Z-48, harboring multiple plant-beneficial traits, to suppress Fusarium wilt disease along with its beneficial effect on seedling and plant growth promotion was analyzed. Among two bacterial strains, B. aryabhattai Z-48 was able to antagonize the mycelial growth of Fusarium oxysporum f.sp. lycopersici in vitro and its application as a seed coating superiorly benefited seedling traits like the germination percentage, vigor index, and seedling growth index along with a reduced germination time. The seed coating with B. aryabhattai Z-48 resulted in significant increases in the shoot length, root length, dry biomass, and total chlorophyll contents when compared with the bioprimed seeds with the same bacterial strain and non-inoculated control plants. The seed coating with B. aryabhattai Z-48 significantly reduced the disease index (>60%) compared with the pathogen control during pot trials. Additionally, the seed coating with B. aryabhattai Z-48 resulted in a significantly higher production of total phenolics, peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase enzyme in tomato plants. The GC/MS-based non-targeted metabolic profiling indicated that the seed coating with B. aryabhattai Z-48 could cause large-scale metabolite perturbations in sugars, sugar alcohols, amino acids, and organic acids to increase the fitness of tomato plants against biotic stress. Our study indicates that a tomato seed coating with B. aryabhattai Z-48 can improve tomato growth and suppress Fusarium wilt disease effectively under conventional agricultural systems.

The impact of melatonin and glutathione on the physiological characteristics of the hot pepper Capsicum annuum L. grown under cadmium pollution

The experiment was conducted in pots within the plastic house of a nursery located in the Al-Muqdadiya district, situated to the north of Baqubah, the central city of Diyala governorate, which lies 90 km northeast of the capital, Baghdad. This study focused on Capsicum annuum L, specifically the Barbarian F1 class of Indian origin, during the autumn season. The objective of the experiment was to investigate the effects of melatonin and glutathione treatments on the physiological characteristics of Capsicum annuum L grown under conditions polluted with cadmium. The research followed a Randomized Complete Block Design (R.C.B.D.) with three replicates. Three treatments were applied: cadmium, added to the soil at concentrations of 0 and 15 mg.kg soil-1, and melatonin and glutathione, applied to the leaves at concentrations of 0, 50, and 100 mg.L-1. The results revealed a significant decrease in fruit carbohydrate content and catalase enzyme activity when treated with cadmium at a concentration of 15 mg.kg soil-1. However, applying melatonin at concentrations of 50 and 100 mg.L-1 led to a significant increase in fruit carbohydrate and protein content, along with a notable rise in catalase and peroxidase enzyme activities. The concentration of 100 mg.L-1 demonstrated the highest mean values for these features. Moreover, the study demonstrated a significant increase in fruit carbohydrate and protein content, as well as catalase enzyme activity, when plants were treated with glutathione at concentrations of 50 and 100 mg.L-1. The highest mean values for these features were observed when plants were treated with glutathione at a concentration of 100 mg.L 1.

Exploring the Associations of Inflammatory and Oxidative Stress Biomarkers with Pancreatic Diseases: An Observational and Mendelian Randomisation Study.

Identifying biomarkers linked to pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis (CP) is crucial for early detection, treatment, and prevention. Methods: Association analyses of 10 serological biomarkers involved in cell signalling (IFN-γ, IL-6, IL-8, IL-10), oxidative stress (superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzyme activities, total glutathione (GSH), malondialdehyde (MDA) levels), and intestinal permeability proteins (zonulin, I-FABP2) were conducted across PDAC (n = 12), CP (n = 21) and control subjects (n = 23). A Mendelian randomisation (MR) approach was used to assess causality of the identified significant associations in two large genetic cohorts (FinnGen and UK Biobank). Results: Observational results showed a downregulation of SOD and GPx antioxidant enzyme activities in PDAC and CP patients, respectively, and higher MDA levels in CP patients. Logistic regression models revealed significant associations between CP and SOD activity (OR = 0.21, 95% CI [0.05, 0.89], per SD), GPx activity (OR = 0.28, 95% CI [0.10, 0.79], per SD), and MDA levels (OR = 2.05, 95% CI [1.36, 3.08], per SD). MR analyses, however, did not support causality. Conclusions: These findings would not support oxidative stress-related biomarkers as potential targets for pancreatic diseases prevention. Yet, further research is encouraged to assess their viability as non-invasive tools for early diagnosis, particularly in pre-diagnostic CP populations.

Evaluating mechanism of banana pseudo-stem retting using seawater: A cost-effective surface pre-treatment approach

Retting has been employed to extract natural fibers from agricultural wastes as a biological and cost-effective approach for centuries. With its global abundance, banana pseudo-stem is a promising agro-waste for lignocellulosic fiber extraction. In this study, fibers were extracted from the pseudo-stems after being pre-treated under four conditions using seawater at room temperature for up to 35 d Bacterial isolation from the fresh seawater sample and screening for ligninolytic ability were conducted. Bacterial load as well as laccase and manganese peroxidase enzyme activity profile assay during the retting duration were analyzed. Fourier transform infrared (FT-IR) and X-day diffraction (XRD) analyses were also examined for both pre-treated and untreated extracted fibers. The results shows that six out of the eight bacterial isolates had the ability to degrade lignin. The treatments (Raw stem + Raw seawater) and (Autoclaved stem + Raw seawater) recorded the highest viable bacterial load of 9.24 × 102 and 4.46 × 102 CFU, respectively, on the 14th day of the retting process. Additionally, the highest laccase and manganese peroxidase enzymes activity was recorded for (Raw stem + Raw seawater) and (Autoclaved stem + Raw seawater) treatments in the second to the third week. The FT-IR spectra of the pre-treated fibers revealed relative reductions in peaks attributed to polysaccharides and other amorphous substances for all retting conditions. The XRD diffractogram revealed that the crystallinity index (CI) of pre-treated fibers increased in all seawater retting treatment conditions. However, the CI for fibers pre-treated under enzymatic conditions were enhanced even after five weeks. Sequence analysis for selected bacterial isolates showed homology to sequences of Bacillus velezensis, Shewanella sp. L8–5, and Citrobacter amalonaticus and Bacillus subtilis j8 strain. From these findings, it was suggested that physical, biological, and chemical actions were collectively involved in the seawater retting process of banana pseudo-stems.

Effect and Mechanism of L-Arginine against Alternaria Fruit Rot in Postharvest Blueberry Fruit.

This study aimed to explore the impact of L-arginine (Arg) on the development of resistance to Alternaria tenuissima (A. tenuissima) in blueberries. The metabolism of reactive oxygen species, pathogenesis-related proteins (PRs), and jasmonic acid (JA) biosynthesis pathways were analyzed, including changes in activity and gene expression of key enzymes. The results indicated that Arg treatment could prevent the development of Alternaria fruit rot in postharvest blueberries. In addition, it was also found to induce a burst of hydrogen peroxide in the blueberries early on during storage, thereby improving their resistance to A. tenuissima. Arg treatment was observed to increase the activity of antioxidant enzymes (peroxidase, catalase, superoxide dismutase, and ascorbate peroxidase) and related gene expression, as well as the total levels of phenolics, flavonoids, and anthocyanin in the blueberries. The activity and gene expression of the PRs (chitinase and β-1,3-glucanase) were elevated in Arg-treated blueberries, boosting their resistance to pathogens. Additionally, a surge in endogenous JA content was detected in Arg-treated blueberries, along with upregulated expression of key genes related the JA biosynthesis pathway (VcLOX1, VcAOS1, VcAOC, VcAOC3, VcOPR1, VcOPR3, VcMYC2, and VcCOI1), thereby further bolstering disease resistance. In conclusion, Arg treatment was determined to be a promising prospective method for controlling Alternaria fruit rot in blueberries.

Acrylic modification as an environmentally acceptable supporter for improving peroxidase enzyme: stability and reusability

This study focuses on the immobilization of horseradish peroxidase (HRP) on modified acrylic fabrics incorporating gold and silver nanoparticles. The process involves treating the acrylic fabrics with hydroxylamine hydrochloride and then coating them with silver and gold nanoparticles. Both obtained materials, treated acrylic fabrics-coated with silver nanoparticles (AgNPs@TA-HAC) and treated acrylic fabrics-coated with gold nanoparticles (AuNPs@TA-HAC), were utilized as supporters for HRP. The physicochemical properties of modified acrylic fabrics were investigated using FTIR, SEM, and zeta potential. HRP immobilized on AgNPs@TA-HAC displayed an activity of 69 units/g support with a specific activity of 4.55 units/mg protein, whereas HRP immobilized on AuNPs@TA-HAC demonstrated an activity of 76 units/g support with a specific activity of 4.75 units/mg protein. After the 15 repetitive cycles, the immobilized HRP on AuNPs@TA-HAC and AgNPs@TA-HAC retained 75 and 59% of their enzymatic activity, respectively. The immobilized HRP on both material supporters retained its activity better compared to the free HRP when exposed to all tested organic solvents. The Michaelis constant (Km) for free HRP and HRP immobilized on AuNPs@TA-HAC and AgNPs@TA-HAC were determined to be 6.23, 8.65, and 9.11 mM, respectively. The maximum reaction rates (V max) for the immobilized HRP on both supports were slightly reduced at 0.71 and 0.69 U/mL, compared to 0.74 U/mL for free HRP. This approach of utilizing acrylic fabrics and metal nanoparticles provides a promising method for enzyme immobilization, with potential applications in various industries.

Microbacterium azadirachtae CNUC13 Enhances Salt Tolerance in Maize by Modulating Osmotic and Oxidative Stress.

Soil salinization is one of the leading threats to global ecosystems, food security, and crop production. Plant growth-promoting rhizobacteria (PGPRs) are potential bioinoculants that offer an alternative eco-friendly agricultural approach to enhance crop productivity from salt-deteriorating lands. The current work presents bacterial strain CNUC13 from maize rhizosphere soil that exerted several PGPR traits and abiotic stress tolerance. The strain tolerated up to 1000 mM NaCl and 30% polyethylene glycol (PEG) 6000 and showed plant growth-promoting (PGP) traits, including the production of indole-3-acetic acid (IAA) and siderophore as well as phosphate solubilization. Phylogenetic analysis revealed that strain CNUC13 was Microbacterium azadirachtae. Maize plants exposed to high salinity exhibited osmotic and oxidative stresses, inhibition of seed germination, plant growth, and reduction in photosynthetic pigments. However, maize seedlings inoculated with strain CNUC13 resulted in significantly improved germination rates and seedling growth under the salt-stressed condition. Specifically, compared with the untreated control group, CNUC13-treated seedlings exhibited increased biomass, including fresh weight and root system proliferation. CNUC13 treatment also enhanced photosynthetic pigments (chlorophyll and carotenoids), reduced the accumulation of osmotic (proline) and oxidative (hydrogen peroxide and malondialdehyde) stress indicators, and positively influenced the activities of antioxidant enzymes (catalase, superoxide dismutase, and peroxidase). As a result, CNUC13 treatment alleviated oxidative stress and promoted salt tolerance in maize. Overall, this study demonstrates that M. azadirachtae CNUC13 significantly enhances the growth of salt-stressed maize seedlings by improving photosynthetic efficiency, osmotic regulators, oxidative stress resilience, and antioxidant enzyme activity. These findings emphasize the potential of utilizing M. azadirachtae CNUC13 as a bioinoculant to enhance salt stress tolerance in maize, providing an environmentally friendly approach to mitigate the negative effects of salinity and promote sustainable agriculture.

Physiological and oxidative stress response of carrot (Daucus carota L.) to jumping plant-louse Bactericera trigonica Hodkinson (Hemiptera: Psylloidea) infestation

BackgroundCarrot is an important vegetable crop grown worldwide. The major economic problem in carrot cultivation is yellow disease caused by Bactericera trigonica, which induces biotic stress and has the greatest impact on crop productivity. Comprehensive studies on the mechanism of carrot defense response to biotic stress caused by B. trigonica infestation have yet to be conducted.MethodsThe changes in photosynthetic pigments, proline, TPC, H2O2 and MDA content, DPPH radical scavenging ability, and antioxidant enzyme activity of SOD, CAT, and POX in carrot leaves in response to insect sex (female and male), rapid response (during the first six hours), and long-term response to B. trigonica infestation were evaluated.ResultsThe results of our study strongly suggest that B. trigonica infestation causes significant changes in primary and secondary metabolism and oxidative status of carrot leaves. Photosynthetic pigment content, TPC, and DPPH and CAT activities were significantly reduced in carrot leaves in response to insect infestation. On the other hand, proline, H2O2 content, and the activity of the antioxidant enzymes superoxide dismutase and peroxidase were increased in carrot leaves after B. trigonica infestation. The results indicate that B. trigonica attenuates and delays the oxidative stress responses of carrot, allowing long-term feeding without visible changes in the plant. Carrot responded to long-term B. trigonica infestation with an increase in SOD and POX activity, suggesting that these enzymes may play a key role in plant defense mechanisms.ConclusionsThis is the first comprehensive study strongly suggesting that B. trigonica infestation causes significant changes in primary and secondary metabolism and an attenuated ROS defense response in carrot leaves that enables long-term insect feeding. The information provides new insights into the mechanisms of carrot protection against B. trigonica infestation.

Effects of sperm concentration on the quality of cryopreserved sperm in Yangtze sturgeon (Acipenser dabryanus)

The Yangtze sturgeon (Acipenser dabryanus) is extinct in the wild; however, artificial propagation in captivity under fully controlled conditions has been successful. Sperm cryopreservation is an effective method for germplasm conservation and aquaculture. Sperm concentration affects the quality of cryopreserved spermatozoa. Thus, in this study, we optimized the concentration (0.25 × 109, 0.5 × 109, 1.0 × 109, and 2.0 × 109 spermatozoa [spz]/mL) for Yangtze sturgeon sperm cryopreservation in a 0.5 mL plastic straw. The greatest value for the kinetic parameters was achieved when sperm were cryopreserved at 0.5 × 109 spz/mL. In comparison to other concentrations, there was a notable increase in both acrosomal and plasma membrane integrity when sperm was cryopreserved at a concentration of 0.5 × 109 spz/mL. No significant difference of superoxide dismutase and glutathione peroxidase enzyme activity was present in post-thaw sperm, except in sperm cryopreserved at a concentration of 2.0 × 109 spz/mL. Catalase activity was significantly higher in post-thaw sperm at a concentration of 0.5 × 109 spz/mL than at other concentrations. Excluding sperm cryopreserved at 2.0 × 109 spz/mL, the fertilization rate of cryopreserved sperm was not significantly different among the different concentrations. This concentration optimization improves cryopreserved sperm quality and standardizes sperm cryopreservation procedures for the Yangtze sturgeon. These findings are especially beneficial for the establishment of a sperm cryobank.

Controlled Atmosphere Storage and Sorbitol Dipping Minimize Chilling Injuries in ‘Palmer’ Mangoes

Our previous studies have shown that ‘Palmer’ mangoes immersed in solutions containing 2.5% sorbitol and stored under a controlled atmosphere (CA) at 8 °C for 30 days had fewer symptoms of a chilling injury. However, there is no information regarding the effectiveness of sorbitol treatment in other atmospheres and/or in combination with lower temperatures. Thus, the objective of this study was to assess the impact of dipping ‘Palmer’ mangoes in 0.1% and 2.5% (w/v) sorbitol solutions and storing the fruit under a CA without atmosphere modification (21 kPa O2 + 0.03 kPa CO2) at 8 °C/95% relative humidity (RH) or with 5 kPa O2 + 5 kPa CO2 at 4 °C/95% RH for 28 days. The fruits were evaluated periodically for chilling injuries, quality, and oxidative metabolism. A chilling injury (CI) was correlated with increased fresh weight loss (FWL) and changes in the color of the epicarp (Lpeel, h°peel, and Cpeel) and mesocarp (L*pulp). Lipid peroxidation (LPpulp and LPpeel) and the hydrogen peroxide content (H2O2peel and H2O2pulp) were associated with the development of a CI, particularly after being transferred to ambient. The treatment with 2.5% sorbitol was more effective in minimizing the chilling injury symptoms and did not compromise the fruit quality, especially when it was stored at 4 °C in association with a CA containing 5 kPa O2 + 5 kPa CO2. This treatment reduced lipid peroxidation and increased the activities of the superoxide dismutase (SOD) and ascorbate peroxidase (APX) enzymes in the epicarp and mesocarp, providing greater cold tolerance. The use of 2.5% sorbitol has been identified as the most efficacious approach for mitigating the adverse impacts of chilling injuries, preserving the fruit quality, and enhancing oxidative metabolism, even at lower temperatures. Thus, this treatment represents a viable alternative for managing chilling injuries in mangoes.