Related Antioxidant Enzyme Activities Research Articles

X-ray irradiation as a potential postharvest treatment for maintaining the quality of lily (Lilium davidii var. unicolor) bulbs and predicting shelf life using an artificial neural network.

This study aimed to investigate the impact of X-ray irradiation pretreatment at varying doses (0.5, 1.0, 1.5, 2.0kGy) on the preservation quality of lily bulbs and to elucidate its potential regulatory mechanisms. The findings revealed that X-ray irradiation significantly inhibited the growth and propagation of microorganisms, with a pronounced bactericidal efficacy at a dose of 1.0kGy. The bactericidal rate against total bacteria was 79.04% on day 0 and 57.59% on day 60, effectively slowing the degeneration process of lily bulbs. By enhancing antioxidant-related enzyme activities, lily bulbs successfully reduced lipid peroxidation within cellular membranes, thereby increasing overall antioxidant capacity. Additionally, X-ray treatment effectively delayed the discoloration process in lily bulbs. The Backpropagation Neural Network (BPNN) model accurately predicts the shelf life of lily bulbs, which was extended to 110days with a 1.0kGy dose. These pivotal discoveries not only enhance the maintenance of storage quality and prolong the shelf life of lily bulbs but also offer a distinctive perspective on reducing postharvest losses and increasing the utilitarian value of this botanical species.

Glycine betaine enhances chilling tolerance in peach fruit by modulating PpbHLH130-mediated antioxidant metabolism

Peaches are vulnerable to chilling injury (CI) after long-term refrigeration. Glycine betaine (GB) treatment was found to substantially mitigate CI in peach fruit, but its molecular mechanism is still unclear. In this study, 288 uniformly sized fruit for three repetitions were immersed in 10 mmol L−1 GB for 10 min and then stored at 5 ± 0.5 °C for 49 d. GB-treated peaches retained lower levels of internal browning index, relative conductivity and malondialdehyde content compared to control during cold storage. Meanwhile, GB treatment increased the gene expression and activities of catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and peroxidase (POD), accompanied by decreased reactive oxygen species (ROS) content in cold stored peaches. Moreover, PpbHLH130 transcription factor was cloned by a one-step cloning method from peaches, which was located in the nucleus with transcriptional activation ability. PpbHLH130 expression was induced by chilling stress and GB treatment. Further investigation revealed that PpbHLH130 up-regulated the expression of PpPOD and PpAPX by directly interacting with E-box elements in their promoters. Therefore, these results indicated that GB treatment activated the PpbHLH130-mediated transcriptional activation of PpPOD and PpAPX genes, improved the gene expression and activities of antioxidant-related enzymes and suppressed the accumulation of ROS, contributing to the maintenance of cell membrane integrity and the improvement of chilling tolerance in refrigerated peach fruit.

Transcriptomic and Metabolomic Analysis Reveals the Potential Roles of Polyphenols and Flavonoids in Response to Sunburn Stress in Chinese Olive (Canarium album).

Sunburn stress is one of the main environmental stress factors that seriously affects the fruit development and quality of Chinese olive, a tropical and subtropical fruit in south China. Therefore, the understanding of the changes in physiological, biochemical, metabolic, and gene expression in response to sunburn stress is of great significance for the industry and breeding of Chinese olive. In this study, the different stress degrees of Chinese olive fruits, including serious sunburn injury (SSI), mild sunburn injury (MSI), and ordinary (control check, CK) samples, were used to identify the physiological and biochemical changes and explore the differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) by using transcriptomics and metabolomics. Compared with CK, the phenotypes, antioxidant capacity, and antioxidant-related enzyme activities of sunburn stress samples changed significantly. Based on DEG-based KEGG metabolic pathway analysis of transcriptomics, the polyphenol and flavonoid-related pathways, including phenylpropanoid biosynthesis, sesquiterpenoid, and triterpenoid biosynthesis, monoterpene biosynthesis, carotenoid biosynthesis, isoflavonoid biosynthesis, flavonoid biosynthesis, were enriched under sunburn stress of Chinese olive. Meanwhile, 33 differentially accumulated polyphenols and 99 differentially accumulated flavonoids were identified using metabolomics. According to the integration of transcriptome and metabolome, 15 and 8 DEGs were predicted to regulate polyphenol and flavonoid biosynthesis in Chinese olive, including 4-coumarate-CoA ligase (4CL), cinnamoyl-CoA reductase (CCR), cinnamoyl-alcohol dehydrogenase (CAD), chalcone synthase (CHS), flavanone-3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS). Additionally, the content of total polyphenols and flavonoids was found to be significantly increased in MSI and SSI samples compared with CK. Our research suggested that the sunburn stress probably activates the transcription of the structural genes involved in polyphenol and flavonoid biosynthesis in Chinese olive fruits to affect the antioxidant capacity and increase the accumulation of polyphenols and flavonoids, thereby responding to this abiotic stress.

Synergistic Effect of Maternal Micronutrient Supplementation on ORFV DNA Vaccine Immune Response in a Pregnant Model.

Contagious ecthyma is a contagious zoonotic disease caused by the Orf virus that can infect farm animals and humans, but no vaccine is available for pregnant mothers. Excessive oxidative stress during pregnancy can suppress the vaccine immune response in pregnant mothers; hence, maternal micronutrient supplementation could effectively improve the immune response, health, and oxidative status during pregnancy. In this study, we employed an 8-week-old pregnant rat model to receive a single intramuscular dose of 200µg of ORF DNA vaccine with or without vitamin E and selenium supplementation to evaluate their effect on immune responses (specific IgG and IgG isotypes), oxidative stress, liver enzymes, and blood glucose levels in maternal-neonatal serum and milk secretions. Additionally, antioxidant-related gene expressions were analyzed in the maternal placenta and pups' liver. The results showed that supplementation of vitamin E and selenium with ORF DNA vaccination increased the production of specific antibody and IgG isotypes (IgG1 and IgG2a) and reduced the oxidative stress in neonatal-maternal serum and milk compared to both the control group and those vaccinated without supplementation (p < 0.05). Notably, the ORF DNA vaccine did not cause oxidative stress and hepatic damage. However, combined supplementation of vitamin E and selenium with DNA vaccination significantly decreased serum malondialdehyde (MDA) levels and improved the antioxidant-related enzyme activities of glutathione peroxidase (GPX), superoxide dismutase 1 (SOD1), and selenoprotein P (SELP) in the maternal placenta and liver of pups (p < 0.05). In conclusion, maternal supplementation of vitamin E and selenium enhanced the immune responses of the ORF DNA vaccine by mitigating oxidative stress in pregnant rats and could thus be a promising strategy for better health outcomes for both mothers and neonates.

Anesthetic effects of eugenol on adult ridgetail white prawn (Exopalaemon carinicauda) and its protective effects under simulated transportation

Anesthesia is a common practice used to improve animal welfare and reduce the negative impacts of stress factors in aquaculture settings. However, few studies have been conducted to investigate the application of anesthetics in ridgetail white prawn (Exopalaemon carinicauda). In the present study, the anesthetic efficacy and protective effects of eugenol in adults of this species were evaluated. When the prawns (n = 5) were immersed in different concentrations of eugenol in the range of 0–240 μL/L for 30 min, the results showed that 180 and 240 μL/L could lead to quick sedative and anesthesia effects with 100% mortality after 30 min exposure, while 30 μL/L failed to induce any sedative and anesthesia effects. Further tests showed that adult individuals were quickly anesthetized by eugenol at a concentration of 60–90 μL/L with a 30 min immersion, while half of the prawns were sedated in 30 μL/L eugenol after 4 h exposure, then recovered at 2 h without any mortality. Furthermore, we checked the water quality parameters after the adult prawns were immersed in four eugenol concentrations (0, 10, 20, 30 μL/L) for 8 h of simulated transportation followed by a 96 h recovery, we found that 30 μL/L eugenol treatment could significantly decrease the ammonia nitrogen concentration, and increased the survival rate at 96 h post recovery. The oxidative responses of the prawns during the 8 h transportation at 30 μL/L eugenol followed by 96 h recovery period were analyzed. The results showed that eugenol administration significantly decreased the malonaldehyde (MDA) concentration and the activities of most antioxidant-related enzymes immediately. The present data indicated that eugenol was an efficient anesthetic, which could be used for long-distance transportation of this species. It exhibited excellent protective effects to improve the animal's welfare by improving water quality and alleviating oxidative stress.

Effects of Ferulic Acid on Respiratory Metabolism, Oxidative Lesions, and Apoptotic Parameters in Gills and Red Blood Cells of Carp (Cyprinus carpio Var. Jian) Response to Copper.

In sustainable aquaculture systems, copper sulfate (CuSO4) is widely applied as a disinfectant to control parasitic infections and algal growth. However, aquatic organisms may suffer from exposure to excessive concentrations of Cu. Elevated Cu concentrations could activate damage to the respiratory functions of aquatic animals. Thus, this study explored the effects exerted by ferulic acid (FA) on respiratory metabolism, oxidation-related lesions, and the apoptosis parameters of the gills and red blood cells in copper sulfate pentahydrate (CuSO4·5H2O)-treated carp (Cyprinus carpio var. Jian). When the 30-day feeding experiment was completed, the carp were exposed to 12.5 μM of Cu for 4 days. The results indicated that the Cu decreased the oxygen consumption and ammonia excretion rates in the carp, reduced the metabolic- and antioxidant-related enzyme activities and glutathione levels in the carp, and enhanced the caspase activities and reactive oxygen species and malondialdehyde levels in the gills of the carp. Moreover, in addition to the changes in the above parameters, the Cu decreased the cell numbers and hemoglobin concentrations and increased the phosphatidylserine exposure and cytochrome c levels in the red blood cells of the carp. These results demonstrate that Cu is capable of decreasing respiratory metabolism and increasing oxidation-related lesions and apoptosis inside the gills and red blood cells of the fish. However, dietary FA quenched the Cu-induced apoptosis and oxidative lesions by reversing the same biomarker indicators, thereby suppressing the Cu-induced decrease in respiratory metabolism. Thus, FA can be used as a suppressor of Cu stress in fish.

Evaluation of palmatine as an immunostimulant in diet for genetically improved farmed tilapia (GIFT, Oreochromis niloticus)

Palmatine as a medicinal herbs extract has strong bacteriostatic ability and is a promising source of antibacterial additive. The objective of this study was to assess the feasibility of palmatine as an antibiotic alternative in diet for genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Four experimental diets were formulated with 0, 200, 400, and 800 mg/kg palmatine. Tilapia with consistent size (initial body weight 3.43 ± 0.02 g) were fed the test diets twice daily for ten weeks. Dietary palmatine inclusion regardless of levels unaffected the growth performance and feed efficiency (P > 0.05). However, dietary 200–800 mg/kg palmatine inclusion reduced the levels of total cholesterol and low-density lipoprotein cholesterol as well as the ratios of low-density/high-density lipoprotein cholesterol and aspartate/alanine aminotransferase in serum (P < 0.05), but generally improved the antioxidant-related enzymes activities in intestine, plasma and liver, the immunoglobulin M, complement 3, and complement 4 contents and lysozyme activity in plasma, and the phagocytic activity of macrophages in head kidney. Bacterial challenge test demonstrated that dietary supplementation with 200–800 mg/kg palmatine enhanced the resistance of tilapia to Aeromonas hydrophila, and the relative percentage survival was the highest in fish fed diet with 400 mg/kg palmatine. In conclusion, dietary palmatine supplementation enhanced the antioxidant and innate immune responses as well as the resistance against A. hydrophila without compromising growth performance of tilapia, and the suitable inclusion level of palmatine was 400 mg/kg of diet for tilapia.

Lipid-Lowering and Antioxidant Effects of Self-Assembled Astaxanthin-Anthocyanin Nanoparticles on High-Fat Caenorhabditis elegans.

Obesity has become a serious global public health risk threatening millions of people. In this study, the astaxanthin-anthocyanin nanoparticles (AXT-ACN NPs) were used to investigate their effects on the lipid accumulation and antioxidative capacity of the high-sugar-diet-induced high-fat Caenorhabditis elegans (C. elegans). It can be found that the lifespan, motility, and reproductive capacity of the high-fat C. elegans were significantly decreased compared to the normal nematodes in the control group. However, treatment of high-fat C. elegans with AXT-ACN NPs resulted in a prolonged lifespan of 35 days, improved motility, and a 22.06% increase in total spawn production of the nematodes. Furthermore, AXT-ACN NPs were found to effectively extend the lifespan of high-fat C. elegans under heat and oxidative stress conditions. Oil-red O staining results also demonstrated that AXT-ACN NPs have a remarkable effect on reducing the fat accumulation in nematodes, compared with pure astaxanthin and anthocyanin nanoparticles. Additionally, AXT-ACN NPs can significantly decrease the accumulation of lipofuscin and the level of reactive oxygen species (ROS). The activities of antioxidant-related enzymes in nematodes were further measured, which revealed that the AXT-ACN NPs could increase the activities of catalase (CAT), superoxidase dismutase (SOD), and glutathione peroxidase (GSH-Px), and decrease the malondialdehyde (MDA) content. The astaxanthin and anthocyanin in AXT-ACN NPs showed sound synergistic antioxidation and lipid-lowering effects, making them potential components in functional foods.

Anti-aging activities of neutral and acidic polysaccharides from Polygonum multiflorum Thunb in Caenorhabditis elegans

Polygonum multiflorum Thunb (PM) is used to slow the aging process. Although polysaccharides are a major constituent of PM, their anti-aging properties have not been thoroughly investigated. Therefore, this study aimed to examine the anti-aging effects of polysaccharides extracted from PM using the Caenorhabditis elegans (C. elegans) model. Two types of water-soluble heteropolysaccharides, namely a neutral polysaccharide (RPMP-N) and an acidic polysaccharide (RPMP-A), were obtained from PM. Their structures were elucidated by various methods. The effects of these polysaccharides on the lifespan, levels of antioxidants, and activities of antioxidant-related enzymes in C. elegans were also evaluated. The results showed that RPMP-A had higher GalA content compared with RPMP-N. The average molecular weights of RPMP-N and RPMP-A were 245.30 and 28.45 kDa, respectively. RPMP-N is a α-1,4-linked dextran as the main chain, and contains a small amount of branched dextran with O-6 as the branched linkage site；RPMP-A may be a complex of α-1,4-linked dextran, HG and RG-I. Treatment with RPMP-N and RPMP-A increased the mean lifespan of C. elegans, and significantly regulated oxidative stress. RPMP-A exhibited stronger anti-aging effects compared with RPMP-N. These findings suggest that RPMP-A may be a potent antioxidant and anti-aging component that can be used for developing functional food products and effective dietary supplements.

Effects of abamectin on nonspecific immunity, antioxidation, and apoptosis in red swamp crayfish (Procambarus clarkii)

Abamectin, a pesticide of 16-member macrocyclic lactones, is widely applied in agriculture. As an important environmental factor, pesticides pose a great threat to defense system in aquatic animals. Procambarus clarkii is one of the most important economic aquatic animals in China. It is necessary to explore the defense mechanism of P. clarkii to abamectin. In this study, P. clarkii were exposed to 0, 0.2, 0.4, 0.6 mg/L abamectin, immune- and antioxidant-related enzymes activities, genes expression levels, and histological observations were used to analyze the defense capacity of P. clarkii to abamectin. With increasing abamectin concentration, reactive oxygen species (ROS) level and malondiadehyde (MDA) content increased significantly. Meanwhiile, acid phosphate (ACP), alkaline phosphatase (AKP) activities, total haemocyte counts (THC), and Crustin expression level decreased significantly, superoxide dismutase (SOD), catalase (CAT) activities, total antioxidant capacity (T-AOC), and GPX expression level also decreased significantly. Hematoxylin & eosin (H&E) observation showed that with increasing abamectin concentration, hepatopancreas were damaged, especially membrane structure. Through TUNEL observation and apoptosis-related genes (PcCTSL, Bcl-2, Bax, BI-1, PcCytc, caspase-3) expression levels, with increasing abamectin concentration, apoptosis rate increased significantly. Results of this study indicated that abamectin caused oxidative damage to P. clarkii, resulting in damage to defense system, suppression of nonspecific immunity and antioxidation, and promotion of apoptosis. It provided theoretical basis for healthy P. clarkii culture, and for further study on defense mechanism of aquatic animals to pesticides.

Transcriptomic and Physiological Analysis Reveals Genes Associated with Drought Stress Responses in Populus alba × Populus glandulosa.

Drought stress affects plant productivity by altering plant responses at the morphological, physiological, and molecular levels. In this study, we identified physiological and genetic responses in Populus alba × Populus glandulosa hybrid clones 72-30 and 72-31 after 12 days of exposure to drought treatment. After 12 days of drought treatment, glucose, fructose, and sucrose levels were significantly increased in clone 72-30 under drought stress. The Fv/Fo and Fv/Fm values in both clones also decreased under drought stress. The changes in proline, malondialdehyde, and H2O2 levels were significant and more pronounced in clone 72-30 than in clone 72-31. The activities of antioxidant-related enzymes, such as catalase and ascorbate peroxidase, were significantly higher in the 72-31 clone. To identify drought-related genes, we conducted a transcriptomic analysis in P. alba × P. glandulosa leaves exposed to drought stress. We found 883 up-regulated and 305 down-regulated genes in the 72-30 clone and 279 and 303 in the 72-31 clone, respectively. These differentially expressed genes were mainly in synthetic pathways related to proline, abscisic acid, and antioxidants. Overall, clone 72-31 showed better drought tolerance than clone 72-30 under drought stress, and genetic changes also showed different patterns.

Dandelion (Taraxacum mongolicum) Extract Alleviated H2O2-Induced Oxidative Damage: The Underlying Mechanism Revealed by Metabolomics and Lipidomics.

Dandelion has received wide attention in food and medicine fields due to its excellent antioxidant properties. Nonetheless, the underlying mechanism of this action has not yet been fully clarified, particularly at the metabolic level. Herein, the effects of dandelion extract (DE) on H2O2-induced oxidative damage was investigated. The results indicate that the DE alleviated H2O2-induced cell damage (increased by 14.5% compared to H2O2 group), reduced the reactive oxygen species (ROS) level (decreased by 80.1% compared to H2O2 group), maintained the mitochondrial membrane potential (MMP) level, and increased antioxidant-related enzyme activities. Importantly, the metabolic response of PC12 cells indicates that H2O2 disturbed phospholipid metabolism and damaged cell membrane integrity. In addition, energy metabolism, the central nervous system, and the antioxidant-related metabolism pathway were perturbed. In contrast, DE rescued the H2O2-induced metabolic disorder and further alleviated oxidative damage. Collectively, these findings provide valuable stepping stones for a discussion of the mechanism and show the promise of DE as a suitable additive for functional food products.

Sparassis latifolia Polysaccharide Attenuates Cholesterol in Rats Maintained on a High-Fat, High-Cholesterol Diet

Sparassis latifolia polysaccharide (SLP) has broad application prospects as a raw material of functional food. This study aimed to investigate the effects of SLP on liver cholesterol metabolism and its mechanism. Sprague–Dawley rats were fed a high-fat, high-cholesterol diet, and various assessments were conducted including hematoxylin and eosin staining, measurement of liver and metabolic indices, and antioxidant analysis. In addition, fluorescence quantitative reverse transcription-polymerase chain reaction was performed to analyze mRNA expression, and gas chromatography-mass spectrometry was employed for screening differential metabolites. The results demonstrated that SLP reduced the abnormal increase in the liver index caused by high fat and cholesterol and improved liver tissue morphology, metabolism level, and antioxidant-related enzyme activities. The polysaccharide regulated the liver sterol metabolism pathway, decreased the mRNA expression levels of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoAR) and sterol O-acyltransferase 1 (SOAT1), upregulated the mRNA expression levels of cholesterol 7α hydroxylase (CYP7α-1) and ABCA1, and increased the contents of propionic acid and butyric acid in the liver. These findings indicated a novel pathway through which SLP prevented hepatic lipid deposition and ameliorated sterol metabolism via regulating the HMG-CoAR-CYP7α-1 axis.

Transcriptomics and metabolomics reveal the molecular and metabolic adaptation to heat stress in Manila clam Ruditapes philippinarum

Temperature is an important environmental factor affecting metabolism, growth and life activities of marine bivalves. To reveal the molecular and metabolic responses to heat stress, comparative transcriptomics and metabolomics were performed in the commercially important bivalve, Manila clam Ruditapes philippinarum. Comparative transcriptomics revealed a total of 3980 differential genes (DEGs) mainly involved in energy metabolism, protein processing, glycerolphospholipid metabolism, inoxidizability and anti-apoptosis. Comparative metabolomic analysis identified 293 differential metabolites (DEMs) in the heat-stressed clams, including Acetyl-CoA, Beta-D-Glucose, phosphatidylcholine and free amino acids. For the heat-stress clams, they showed the significantly increased enzyme activities of AKP and ACP, as well as antioxidant-related enzyme activities (SOD and CAT) and oxidative damage substance (MDA). The changes in gene expression of glycolysis-related genes (GLUT1, GLK, HK1 and GPI6) and metabolites (Beta-D-Glucose and Acetyl-CoA) reflect the adjusted energy metabolism in the heat-stressed clams. The protein processing in endoplasmic reticulum may play the important roles in the stability of cell membrane structure during heat adaptation. The increased contents of glycerophospholipid (PC) may be essential to maintain the stability and permeability of cell membrane in the heat-stressed clams. Molecular chaperones (HSP70 and HSP90) may participate in the degradation of misfolded proteins to maintain cell homeostasis during the heat stress. To defense the heat stress, clams also initiate the protection and defense mechanisms by activating antioxidant system, innate immune system and anti-apoptotic system. These findings will shed new lights on molecular and metabolic adaptation to heat stress in the intertidal mollusks in a warming climate at the global scale.

Bacillus coagulans (Weizmannia coagulans) XY2 attenuates Cu-induced oxidative stress via DAF-16/FoxO and SKN-1/Nrf2 pathways and gut microbiota regulation

Copper (Cu) pollution has become a serious environmental problem especially in recent decades. In this study, the mechanisms of Bacillus coagulans (Weizmannia coagulans) XY2 against Cu-induced oxidative stress were explored through a dual model. In mice, Cu disturbed microbial community structure, revealing an increased level of Enterorhabdus abundance and decreased levels of Intestinimonas, Faecalibaculu, Ruminococcaceae and Coriobacteriaceae_UCG-002 abundance. Meanwhile, B. coagulans (W. coagulans) XY2 intervention reversed this trend along with alleviated Cu-induced metabolic disturbances by increasing levels of hypotaurine and L-glutamate and declining levels of phosphatidylcholine and phosphatidylethanolamine. In Caenorhabditis elegans, nuclear translocation of DAF-16 and SKN-1 was inhibited by Cu, which in turn suppressed antioxidant-related enzymes activities. XY2 mitigated biotoxicity associated with oxidative damage caused by Cu exposure via regulating DAF-16/FoxO and SKN-1/Nrf2 pathways and intestinal flora to eliminate excess ROS. Our study provides a theoretical basis formulating future strategy of probiotics against heavy metal contamination.

The Effect of Guisangyou Tea on Abnormal Lipid Metabolism in Mice Induced by High-Fat Diet.

This study was aimed to investigate the effect of Guisangyou tea (GSY tea) in improving abnormal lipid metabolism in mice with obesity induced by a high-fat diet (HFD). The results showed that intervention of the water extract of GSY tea (WE) decreased serum levels of lipids, and positively regulated the related antioxidant enzyme activities and the inflammatory factors in the serum and liver. In the liver, the mRNA and protein expression levels of sterol regulatory element-binding proteins-1 (SREBP-1), stearoyl-CoA desaturase-1 (SCD-1), fatty acid synthase (FASN), and acetyl CoA carboxylase (ACC) related to lipid synthesis were downregulated, and the mRNA and protein expression levels of the farnesoid X receptor (FXR) and small heterodimer partner (SHP) related to bile acid production were upregulated. The results demonstrate that GSY tea can improve abnormal lipid metabolism in obese mice by improving the body's antioxidant capacity, regulating the inflammatory state, and reducing the synthesis of lipids and increasing the production of bile acids. GSY tea can be processed and utilized as a safe and effective resource for improving abnormal lipid metabolism.

Amelioration of Salt-Induced Damage on Paeonia ostii ‘Fengdan’ by Exogenous Application of Silicon

To investigate the amelioration of salt-induced damage on Paeonia ostii ‘Fengdan’ by exogenous silicon, we analyzed the photosynthetic and physiological characteristics of 1.5-year-old ‘Fengdan’ seedlings under NaCl stress by applying exogenous silicon (0, 0.75, and 1.5 mmol/L). Our results showed that the contents of the photosynthetic pigments chlorophyll a, chlorophyll b, and carotene, the transpiration rate, stomatal conductance, and intercellular CO2 were significantly enhanced under salt stress when silicon treatment was applied, implying that the net photosynthetic rate was greatly improved. In addition, the plant height, stem thickness, and above-ground dry biomass of tree peony seedlings were effectively increased under salt stress with low-concentration silicon (0.75 mmol/L) treatment, along with osmotic substance (SS, SP, and Pro) content, total polyamine (TP) contents, and the activities of antioxidant-related enzymes (SOD, POD, and CAT) and polyamine-related synthetases (ADC, ODC, and SAMDC). In the low-concentration silicon treatment, malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anions (O2−) were transformed quickly, which eventually reduced cell oxidative damage and improved seedling tolerance. This is an important finding in the understanding of how exogenous low-concentration silicon can alleviate salt-induced damage and promote the growth of tree peony seedlings, thus providing a new perspective on tree peony cultivation.

The role of AccCDK20 and AccCDKN1 from Apis cerana cerana in development and response to pesticide and heavy metal toxicity

Apis cerana cerana is a native bee species in China and plays a key role in agricultural production and ecological balance. However, the growth and development of Apis cerana cerana has not been smooth, and pesticide and heavy metal stress are key factors that have forced a dramatic decline in population size. This study was performed with the objective of investigating the role of AccCDK20 and AccCDKN1 in honey bee resistance to pesticide and heavy metal stress. RT–qPCR analysis revealed that AccCDK20 transcript levels were highest in brown-eyed pupae and AccCDKN1 transcript levels were highest in 1-day-old worker bees. In different tissues and body parts of adult bees, AccCDK20 transcript levels were highest in the head, and AccCDKN1 transcript levels were highest in the thorax. It was further observed that environmental stress can affect the transcript levels of the AccCDK20 and AccCDKN1 genes. Silencing of the AccCDK20 and AccCDKN1 genes resulted in altered activities of antioxidant-related genes and antioxidant-related enzymes. AccCDK20 and AccCDKN1 transcript levels were upregulated under glyphosate stress, and silencing of the genes resulted in reduced resistance to glyphosate and greatly increased mortality in Apis cerana cerana. In addition, gene function was verified by in vitro repression assays. Overexpression of the AccCDK20 and AccCDKN1 proteins in E. coli cells increased the resistance to ROS damage induced by CHP. In conclusion, AccCDK20 and AccCDKN1 play an indispensable role in honey bee resistance to pesticide and heavy metal stress.

Impact of Titanium Dioxide-Graphene Oxide (TiO2-GO) Composite Nanoparticle on the Juveniles of the Giant River Prawn, Macrobrachium rosenbergii: Physio-Biochemistry and Transcriptional Response

Nanomaterials are used in many fields, resulting in inevitably releasing into the aquatic environment. The presence of nanomaterials, including TiO2-GO in the aquatic environment, can be toxic to aquatic organisms. However, few studies have focused on the effects of TiO2-GO composite nanoparticle on crustaceans. In the present study, the giant river prawn Macrobrachium rosenbergii juveniles were exposed to two concentrations of TiO2-GO composite nanoparticle (0.1 and 0.5mg/L). The effects of TiO2-GO composite exposure on activities of digestive and antioxidant-related enzymes and expressions of growth and immune-related genes at the transcriptome were studied. The results showed that the survival rate and growth performance were not negatively affected by TiO2-GO composite at the two exposure levels. Nevertheless, exposure to TiO2-GO composite causes an effect on the activities of digestive and antioxidant enzymes in the juvenile prawns. The enzyme activities of CAT, SOD, GSH-Px, AMS, TPS, and LPS in the 0.1mg/L TiO2-GO composite experimental group were markedly reduced than those in the control group. Additionally, the expression level of genes involved in growth and immunity was significantly affected by TiO2-GO composite. After exposure to the 0.1mg/L TiO2-GO composite, the mRNA expression level of MSTN was significantly increased, but the level of EcR, Raptor, and CaBP was significantly decreased. However, the mRNA levels of the CTL, TLR, JAK, and STAT were significantly increased after exposure to the 0.5mg/L concentration of TiO2-GO composite. Furthermore, to understand the molecular mechanism of M. rosenbergii under TiO2-GO composite exposure, RNA-Seq was employed to analyze the changes of the muscle and hepatopancreas transcriptome. Compared with the control group, we identified 5166 and 4784 differentially expressed genes (DEGs) in the muscle and hepatopancreas, respectively (p < 0.05). Based on gene ontology and KEGG analysis, significant differences were observed in the DEGs involved in activity and binding, metabolism, immune response, and environmental information processing. These results showed that exposure to TiO2-GO composite nanoparticle led to the changes of enzyme activity and gene expression, suggesting that TiO2-GO composite existing in aquatic environments would disrupt the physiology of M. rosenbergii. This study will serve as a foundation for subsequent research into the evaluation of nanomaterial toxicity on crustacean species.

Effects of titanium dioxide (TiO2)/activated carbon (AC) nanoparticle on the growth and immunity of the giant freshwater prawn, Macrobrachium rosenbergii: potential toxicological risks to the aquatic crustaceans.

Due to their unique physicochemical characteristics, nanomaterials exhibit many excellent properties and functions, leading to their applications in numerous fields. The large-scale production and widespread application of nanomaterials have inevitably resulted in their release into the environment, especially the water environment. Several studies have confirmed that exposure to nanomaterials can be toxic to aquatic organisms. However, few studies have focused on the effects of nanomaterial exposure on growth and immunity in crustaceans. In the present study, juvenile Macrobrachium rosenbergii were exposed to different concentrations of titanium dioxide (TiO2)/activated carbon (AC) composite nanomaterial (0.1 and 0.5mg/L) for 45days. The effects of nanoparticle exposure on digestion and antioxidant-related enzyme activities, as well as the expression of growth and immunity-related genes and signaling pathway, were evaluated. Our results show that in response to low concentration of TiO2/AC nanoparticle (0.1mg/L), most of the enzyme activities related to digestion and antioxidation (TPS, LPS, AMS, SOD, and CAT) were diminished. On the contrary, the GSH-Px activity increased under the 0.1mg/L group of TiO2/AC nanoparticle concentration. Additionally, the level of digestive and antioxidant enzyme activities we detected was increased when exposed to 0.5mg/L TiO2/AC nanoparticle. By comparison to the expression level of growth-related genes in the control group, MSTN, CaBP, E75, Raptor, EcR, and EGF were significantly inhibited at 0.1 and 0.5mg/L concentrations of TiO2/AC nanoparticle, whereas the expression level of genes (TLR, JAK, STAT, PPAF, ACP, and AKP) related to immunity was increased when exposed to different concentrations of TiO2/AC nanoparticle. Compared with the control group (0mg/L concentration), 5166 DEGs were identified in the TiO2/AC nanoparticle group, and a large number of DEGs were involved in molting, energy metabolism, stress tolerance, and germ cell development. Moreover, KEGG analysis revealed that many DEGs were assigned into signaling pathways related to metabolic growth and immune stress. These results showed that exposure to TiO2/AC nanoparticle will result in the changes of enzyme activity and routine mRNA expression, suggesting that TiO2/AC nanoparticle which existed in aquatic environment might affect the physiology of M. rosenbergii. This study will provide significant information for the evaluation of nanomaterial toxicity on aquatic crustaceans.