Expression Of Glutathione S-transferase Research Articles

Walnut ethylene response factor JrERF2-2 interact with JrWRKY7 to regulate the GSTs in plant drought tolerance

Juglans regia is a world-famous woody oil plant, whose yield and quality are affected by drought stress. Ethylene-responsive factors (ERFs) play vital role in plant stress response. In current study, to comprehend the walnut molecular mechanism of drought stress response, an ERF transcription factor was clarified from J. regia (JrERF2–2) and its potential function mechanism to drought was clarified. The results showed that JrERF2–2 could be induced significantly by drought. The transgenic Arabidopsis over-expression of JrERF2–2 displayed enhanced growth, antioxidant enzyme vitalities, reactive oxygen species scavenging and proline produce under drought stress. Especial the glutathione-S-transferase (GST) activity and most GST genes’ transcription were elevated obviously. Yeast one-hybrid (Y1H) and co-transient expression (CTE) methods revealed that JrERF2–2 could recognize JrGST4, JrGST6, JrGST7, JrGST8, and JrGSTF8 by binding to GCC-box, and recognize JrGST11, JrGST12, and JrGSTN2 by binding to DRE motif. Meanwhile, the binding activity was strengthened by drought stress. Moreover, JrERF2–2 could interact with JrWRKY7 to promote plant drought tolerance; JrWRKY7 could also distinguish JrGST4, JrGST7, JrGST8, JrGST11, JrGST12, and JrGSTF8 via binding to W-Box motif. These results suggested that JrERF2–2 could effectively improve plant drought tolerance through interacting with JrWRKY7 to control the expression of GSTs. JrERF2–2 is a useful plant representative gene for drought response in molecular breeding.

Identification and characterization of the novel genes encoding glutathione S-transferases in Mytilus galloprovincialis

The superfamily of glutathione S-transferases (GST) plays an essential role in the xenobiotic metabolism, binding compounds to the glutathione, and is like a cell protector during the influence of various negative external factors. Nevertheless, there are very few works devoted to the investigation of these genes in marine invertebrates. Up to this time, only three classes of cytosolic GSTs for one of the leading commercial molluscs Mytilus galloprovincialis were described. We sequenced the whole transcriptome from the gill tissues and, using bioinformatic analysis, detected ten classes of glutathione S-transferases, which are expressed in the mussel M. galloprovincialis. For the first time, two subfamilies were described: mitochondrial GST (kappa class) and microsomal (MAPEG), as well as five classes of the family of cytosolic GSTs (mu, omega, rho, tau, theta). Omega and sigma GST classes might be rapidly regulated genes due to the lack of introns and this assumption was confirmed by the investigation of short-term hypoxia on M. galloprovincialis. Seven new classes of GST revealed a greater gene variety of this detoxifying enzyme in mussels than expected. The obtained nucleotide sequences are necessary for future investigations of GSTs expression in response to various external factors (pollution, oxygen starvation, infection, etc.).

Environmentally relevant lead (Pb) water concentration induce toxicity in zebrafish (Danio rerio) larvae

Early developmental stages of aquatic organisms including fish are inherently vulnerable to lead (Pb) and other water metal contaminants. However, reports on the deleterious effects of environmentally relevant Pb levels are limited. To this end, we exposed 2.5 h post fertilization (hpf) old zebrafish (Danio rerio) embryos to a range of Pb concentrations encompassing environmentally relevant levels (1, 10, 25, 50 and 100 μg/L Pb) until 96 hpf. Exposure negatively impacted the development and survival of zebrafish embryos by inducing embryo coagulation related mortalities in a concentration-dependent manner. At 24 hpf, the highest level of exposure (100 μg/L Pb) had impaired embryo activity characterized by reduced burst activity and the number of movements per minute made by embryos. At 72 hpf, newly hatched larvae exhibited adverse cardiovascular effects (100 μg/L Pb group) and neuromuscular effects (50 and 100 μg/L Pb groups). The antioxidant system dysregulation evidenced by downregulation of catalase, and upregulation of mRNA expression of glutathione S-transferase and cytochrome oxidase subunit I were observed. The pro-apoptotic tumour protein P53 (TP53) and the anti-apoptotic B cell lymphoma −2 (Bcl-2) mRNA expression levels were also affected. The former was downregulated across exposed groups and the latter was upregulated and downregulated in the groups with Pb concentrations less than 50 μg/L Pb and downregulated in 50 μg/L Pb, respectively. These findings suggest that Pb within environmentally relevant levels may be deleterious to developing zebrafish.

ACC deaminase-producing Brevibacterium linens RS16 enhances heat-stress tolerance of rice (Oryza sativa L.).

The rapid rise in global temperature has adverse effects on rice productivity. The lack of eminent resources for heat stress alleviation is threatening the agricultural sector. Heat stress alleviation by endophytic plant growth-promoting bacteria (PGPB) can be a sustainable and eco-friendly approach. The present study was conducted to check the colonization of Brevibacterium linens RS16 producing ACC (1-aminocyclopropane-1-carboxylate) deaminase in the rice endosphere and to characterize its efficiency in enhancing stress tolerance. The ethylene emission pathway, reactive oxygen species (ROS) concentrations, proline accumulation, expression of glutathione S-transferase (GST), and small heat shock proteins (sHSPs) were monitored at two different levels of heat stress (40°C and 45°C). Bacterial inoculation decreased ethylene emission levels by 26.9% and 24.4% in rice plants exposed to 40°C and 45°C, respectively, compared with the non-inoculated plants. B. linens RS16 also enhanced the expression profiles of glutathione S-transferase. The collective effect of GST expression profiles and decrease in ethylene emission due to bacterial ACC deaminase activity subsequently resulted in a decrease in ROS concentrations. Additionally, HSP16 and HSP26 increased expression in heat-stressed plants inoculated with B. linens RS16 resulted in enhanced stress tolerance (i.e., lesser proline accumulation) than non-inoculated plants. Hence, this study demonstrates the bacteria-mediated tolerance against heat stress by regulating the ethylene emission pathway and upregulating antioxidant enzymes and heat shock proteins.

Sulfur deficiency exacerbates phytotoxicity and residues of imidacloprid through suppression of thiol-dependent detoxification in lettuce seedlings

Sulfur, an essential macronutrient, plays important roles in plant development and stress mitigation. Sulfur deficiency, a common problem in agricultural soils, may disturb plant stress resistance and xenobiotic detoxification. In the present study, the function and mechanism of limited sulfur nutrition on the residues and phtotoxicity of imidacloprid were investigated in lettuce plants. Sulfur deficiency significantly increased imidacloprid accumulation in lettuce tissues, exacerbated imidacloprid biological toxicity by enhancing the accumulation of toxic metabolites, like imidacloprid-olefin. Simultaneously, imidacloprid-induced detoxification enzymes including cytochromes P450, glutathione S-transferases (GSTs) and glycosyltransferases were inhibited under limited sulfur supply. On the other hand, sulfur deficiency further enhanced the generation of reactive oxygen species and exacerbated lipid peroxidation in lettuce tissues. Sulfur deficiency mainly reduced the abundance of thiol groups, which are essential redox modulators as well as xenobiotic conjugators, and significantly inhibited GSTs expression. These results clearly suggested that sulfur deficiency inhibited the synthesis of sulfur-containing compounds, leading to increased accumulation of pesticide residues and toxic metabolites as well as reduced detoxification capacity, consequently leading to oxidative damage to plants. Therefore, moderate sulfur supply in regions where neonicotinoid insecticides are intensively and indiscriminately used may be an efficient strategy to reduce pesticide residues and the potential risk to ecosystem.

Pharmacological and ameliorative effects of Withania somnifera against cadmium chloride-induced oxidative stress and immune suppression in Nile tilapia, Oreochromis niloticus.

This study was carried out to evaluate the effects of dietary supplementation of aqueous extract of Withania somnifera (W. somnifera) against cadmium chloride-induced toxicity in the Nile tilapia, Oreochromis niloticus. Five experimental groups were designed: group (I) was free from cadmium chloride and W. somnifera and served as a control, group (II) was exposed to 1.775 mg L-1 of cadmium chloride only (which is equivalent to 1/4 96-h LC50), while groups (III), (IV), and (V) were exposed to 1.775 mg cadmium chloride L-1 with co-supplementation of dietary W. somnifera in doses of 1.0, 2.0, and 3.0 mL kg-1 body weight (bwt), respectively. The experiment lasted for 4 weeks. In the second and fourth weeks of the experiment, the following indicators were evaluated: hematological (hemogram and blood protein profile), biochemical (activities of serum liver enzymes, namely alanine transaminase (ALT) and aspartate transaminase (AST)), immunological (immunoglobulin M (IgM), serum lysozyme), and tissue antioxidant changes (malondialdehyde (MDA) levels and activities of catalase (CAT) and superoxide dismutase (SOD)). Additionally, gene expressions of glutathione-S-transferase (GST) in the liver were assessed. At the end of the experiment, all fish in all groups were experimentally challenged with Aeromonas hydrophila and the relative protection survival (RPS) was demonstrated. The results revealed that groups exposed to cadmium chloride toxicity and co-supplemented with dietary aqueous extract of W. somnifera at high doses showed significant ameliorative effects in hemogram parameters, total protein, globulin, IgM, and lysozyme against cadmium chloride-induced toxicity compared to the control group and the group exposed to a sublethal dose of cadmium chloride without co-suplemntation of W. somnifera. The results showed also that groups supplemented orally with W. somnifera at high doses have higher antioxidant activities of CAT and SOD and reduction of MDA formation. Levels of gene expressions of GST in the liver were higher in W. somnifera extract-supplemented groups more than those in the group exposed to cadmium chloride-induced toxicity without W. somnifera supplementation. In addition, the results revealed improved RPS with the dietary supply of W. somnifera extract in high doses. In conclusion, this study showed that the dietary supplementation of W. somnifera extract to diets of O. niloticus could be suggested as an effective way to overcome cadmium chloride-induced toxicity because it improves blood parameters and antioxidants, and it can be used as an immunostimulant against the invading bacterial pathogens.

Differential regulation of antioxidant enzymes in Frankliniella occidentalis (Thysanoptera: Thripidae) exposed to thermal stress

Frankliniella occidentalis is an invasive insect pest that incites damage to ornamental and agronomic crops on a global scale. In this study, the effects of temperature on gene expression and enzyme activity were studied for superoxide dismutase (SOD), peroxidase (POD), and glutathione-S-transferase (GST) in F. occidentalis. SOD, POD and GST enzyme activity increased significantly at 35–37 °C but declined as the temperature increased to 41 °C. In a time course study at 35 °C, SOD, POD and GST activities were significantly elevated at 0.5, 1 and 2 h in comparison to the control at 26 °C. Expression patterns were evaluated for the three antioxidant genes under high and low temperature stress. In a time course study at –4 °C, SOD, POD and GST expression peaked at 1 h and declined at 2 h of exposure. In contrast, when transcription was monitored at 35 °C, expression was lowest at 1 h and increased at 2 h. The results provide data that will be useful in deciphering the role of antioxidant enzymes in the adaptation of F. occidentalis to climate change.

Transcriptome analysis and response of three important detoxifying enzymes to Serratia marcescens Bizio (SM1) in Hyphantria cunea (Drury) (Lepidoptera: Noctuidae)

Hyphantria cunea (Drury) (Lepidoptera: Noctuidae) is a main pest of forest trees. In this study, the effects of Serratia marcescens Bizio (SM1) infection on the transcriptome of H. cunea were studied. The expression of 1068 unigenes in the transcriptome of H. cunea infected by S. marcescens was markedly different from that in the control of H. cunea; 474 genes were upregulated, and 594 genes were downregulated in the former. Among them, 8 cytochrome P450s (CYPs), 5 uridine diphosphate-glycosyltransferases (UGTs) and 3 glutathione S-transferases (GSTs) were significantly differentially expressed. Pathway enrichment analysis indicated that these differentially expressed detoxification enzyme genes were mainly involved in the drug metabolism pathway, glutathione metabolism pathway and ABC transporter pathway. Interestingly, we found that five UGTs were related to oestradiol metabolism in the steroid hormone biosynthesis pathway. Furthermore, the real-time fluorescent quantitative PCR results showed that SM1 could induce the expression of CYPs and UGTs, but inhibit the expression of GSTs. This research will identify the response of important detoxification enzymes to S. marcescens, which will provide a theoretical foundation for the development of new immunosuppressants for H. cunea control. Furthermore, H. cunea was performed transcriptome sequencing to explore the key metabolic pathways, signalling pathways and genes affected by S. marcescens, which will clarify the mechanisms of S. marcescens infection of H. cunea. In addition, this study also explored the relationship between H. cunea and S. marcescens, which will provide a theoretical basis for the biological control of H. cunea by using S. marcescens.

Transcriptome Responses of Ripe Cherry Tomato Fruit Exposed to Chilling and Rewarming Identify Reversible and Irreversible Gene Expression Changes.

Tomato fruit stored below 12°C lose quality and can develop chilling injury upon subsequent transfer to a shelf temperature of 20°C. The more severe symptoms of altered fruit softening, uneven ripening and susceptibility to rots can cause postharvest losses. We compared the effects of exposure to mild (10°C) and severe chilling (4°C) on the fruit quality and transcriptome of ‘Angelle’, a cherry-type tomato, harvested at the red ripe stage. Storage at 4°C (but not at 10°C) for 27 days plus an additional 6 days at 20°C caused accelerated softening and the development of mealiness, both of which are commonly related to cell wall metabolism. Transcriptome analysis using RNA-Seq identified a range of transcripts encoding enzymes putatively involved in cell wall disassembly whose expression was strongly down-regulated at both 10 and 4°C, suggesting that accelerated softening at 4°C was due to factors unrelated to cell wall disassembly, such as reductions in turgor. In fruit exposed to severe chilling, the reduced transcript abundances of genes related to cell wall modification were predominantly irreversible and only partially restored upon rewarming of the fruit. Within 1 day of exposure to 4°C, large increases occurred in the expression of alternative oxidase, superoxide dismutase and several glutathione S-transferases, enzymes that protect cell contents from oxidative damage. Numerous heat shock proteins and chaperonins also showed large increases in expression, with genes showing peak transcript accumulation after different times of chilling exposure. These changes in transcript abundance were not induced at 10°C, and were reversible upon transfer of the fruit from 4 to 20°C. The data show that genes involved in cell wall modification and cellular protection have differential sensitivity to chilling temperatures, and exhibit different capacities for recovery upon rewarming of the fruit.

Glutathione-S-transferases genes-promising predictors of hepatic dysfunction.

One of the most commonly known genes involved in chronic diffuse liver diseases pathogenesis are genes that encodes the synthesis of glutathione-S-transferase (GST), known as the second phase enzyme detoxification system that protects against endogenous oxidative stress and exogenous toxins, through catalisation of glutathione sulfuric groups conjugation and decontamination of lipid and deoxyribonucleic acid oxidation products. The group of GST enzymes consists of cytosolic, mitochondrial and microsomal fractions. Recently, eight classes of soluble cytoplasmic isoforms of GST enzymes are widely known: α-, ζ-, θ-, κ-, μ-, π-, σ-, and ω-. The GSTs gene family in the Human Gene Nomenclature Committee, online database recorded over 20 functional genes. The level of GSTs expression is considered to be a crucial factor in determining the sensitivity of cells to a broad spectrum of toxins. Nevertheless, human GSTs genes have multiple and frequent polymorphisms that include the complete absence of the GSTM1 or the GSTT1 gene. Current review supports the position that genetic polymorphism of GST genes is involved in the pathogenesis of various liver diseases, particularly non-alcoholic fatty liver disease, hepatitis and liver cirrhosis of different etiology and hepatocellular carcinoma. Certain GST allelic variants were proven to be associated with susceptibility to hepatological pathology, and correlations with the natural course of the diseases were subsequently postulated.

Functional divergence of three glutathione transferases in two biotypes of the English grain aphid, Sitobion avenae

AbstractThe English grain aphid, Sitobion avenae (Fabricius) (Hemiptera: Aphididae), is a significant pest of cereal crops, but molecular factors and mechanisms that underpin its ability to develop differential biotypes on variable host plants are still not well understood. In this study, we investigated the interactions between two plant secondary metabolites (i.e., gramine and gallic acid) and three glutathione S‐transferases (GSTs) of S. avenae. Using artificial diets complemented or not with one of these two plant compounds, we found that gramine had relatively stronger negative effects on fitness of S. avenae biotype 3 (adapted to barley), and gallic acid on that of biotype 4 (adapted to wheat). Gramine significantly induced overexpression of SaveGST1 and SaveGST2 in biotype 4, but not in biotype 3. Gramine also reduced SaveGST3 expression in biotype 4, but not in biotype 3, suggesting biotype‐specific effect of GSTs’ regulation. In the treatments with gallic acid, the overexpression of SaveGST1, but not SaveGST2 or SaveGST3, was significantly induced in both biotypes, suggesting a critical role of SaveGST1 in detoxification of phenolic compounds such as gallic acid. The total constitutive GST activity was much higher in biotype 4 than in biotype 3. Significant increase in GST activity was obtained by the addition of both secondary metabolites in biotype 4, but not in biotype 3, showing significantly higher expression plasticity of GSTs in biotype 4. Thus, both constitutive and induced expression of GSTs could affect the adaptability of S. avenae on plants with variable secondary compounds, and thus contribute to the divergence of biotypes in this aphid species.

An increase in O-GlcNAcylation of Sp1 down-regulates the gene expression of pi class glutathione S-transferase in diabetic mice

Oxidative stress is a key factor contributing to the development of diabetes complications. Glutathione S-transferases (GSTs) protect against products of oxidative stress by conjugating glutathione to electrophilic substrates, producing compounds that are generally less reactive and more soluble. The expression and activity of GSTs during diabetes have been extensively studied, but little is known about regulation mechanisms of Pi-class GST (GSTP). The aim of the present study was to evaluate how GSTP is regulated in a Streptozotocin (STZ)-induced murine diabetes model. GST activity and GSTP expression were determined in adult male mice diabetized with STZ. Specificity protein 1 (Sp1) expression and O-glycosylation, as well as the role of AP-1 members Jun and Fos in the regulation of GSTP expression, were also assessed. The results showed that GST total activity and GSTP mRNA and protein levels were decreased in the diabetic liver, and returned to normal values after insulin administration. The insulin-mimetic drug vanadate was also able to restore GST activity, but failed to recover GSTP mRNA/protein levels. In diabetic animals, O-glycosylated Sp1 levels were increased, whereas, in insulin-treated animals, glycosylation values were similar to those of controls. After vanadate administration, Sp1 expression levels and glycosylation were lower than those of controls. Our results suggest that hyperglycemia could lead to the observed increase in Sp1 O-glycosylation, which would, in turn, lead to a decrease in the expression of Sp1-dependent GSTP in the liver of diabetic mice.

Effects of Zinc Oxide Nanoparticles on Growth, Intestinal Barrier, Oxidative Status and Mineral Deposition in 21-Day-Old Broiler Chicks.

This experiment was to study the effects of zinc oxide nanoparticles (ZnO-NPs) on growth, intestinal barrier, oxidative status, and mineral deposition. In total, 256 one-day-old chicks were randomly allotted to 4 dietary groups and fed with basal diet plus 80mg/kg ZnSO4 (ZnSO4 group) or plus 40, 80, and 160mg/kg ZnO-NPs, respectively, for 21days. Compared with the ZnSO4 group, dietary 40, 80, and 160mg/kg ZnO-NPs did not alter growth (average daily gain, body weight, and gain to feed ratio), and serum activities of glutamic-pyruvic transaminase, alkaline phosphatase and glutamic oxalacetic transaminase (P > 0.05). However, dietary 80 and 160mg/kg ZnO-NPs linearly decreased serum D-lactate content and diamine oxidase activity (P < 0.01). Moreover, 80mg/kg ZnO-NPs enhanced zonula occludens-1 (ZO-1) mRNA expression in jejunal mucosa (P = 0.02). Dietary ZnO-NPs increased total antioxidant capacity activity (P = 0.01), and 80mg/kg ZnO-NPs decreased malondialdehyde content in jejunal mucosa as compared to the ZnSO4 group (P = 0.02). In contrast, dietary ZnO-NPs did not alter mRNA expressions of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, heme oxygennase-1 (HO-1) and NAD (P)H: quinone oxidoreductase 1 (NQO1) (P > 0.05). No significant difference was found in selected mineral concentrations (Mn, Cu, Fe and Zn) in the liver among ZnSO4 and 3 ZnO-NP groups (P > 0.05). However, 160mg/kg ZnO-NPs increased fecal contents of Zn, Fe and Cu (P < 0.01), but did not affect fecal Mn level (P > 0.05). Therefore, results suggested that ZnO-NPs could be an additive to enhance the intestinal barrier and antioxidant capacity of broiler chicks, whereas the inclusion of 80mg/kg would be more efficient.

Identification of Glutathione S-Transferase Genes in Hami Melon (Cucumis melo var. saccharinus) and Their Expression Analysis Under Cold Stress.

As a group of multifunctional enzymes, glutathione S-transferases (GSTs) participate in oxidative stress resistance and cellular detoxification. Here, we identified 39 CmGST genes with typical binding sites from the Hami melon genome, and they can be classified into seven subfamilies. Their molecular information, chromosomal locations, phylogenetic relationships, synteny relationships, gene structures, protein–protein interactions, structure of 3-D models, and expression levels under cold stress were analyzed. Expression analysis indicates that cold-tolerant Jia Shi-310 (JS) had higher GST enzyme activities and expression levels of 28 stress-related genes under cold stress. Some CmGSTs belonging to Tau, Phi, and DHAR classes play significant roles under cold stress, and they could be regarded as candidate genes for further studies. The present study systematically investigated the characterization of the Hami melon GST gene family, extending our understanding of Hami melon GST mediated stress-response mechanisms in this worldwide fruit.

Different effects of two dietary levels of tea polyphenols on the lipid deposition, immunity and antioxidant capacity of juvenile GIFT tilapia (Oreochromis niloticus) fed a high-fat diet

Long-term feeding of fish with a high-fat diet (HFD) causes excess fat deposition and an impairment of immune function. In the present study, we aimed to determine whether dietary tea polyphenols (TPs) would ameliorate the adverse effects of HFD-feeding in GIFT tilapia. Juvenile GIFT tilapias (5.4 ± 0.9 g) were raised in twelve 200-L tanks (three tanks per diet, 20 fish per tank) and fed a control diet (6% fat, 36% protein), an HFD (12% fat, 36% protein), or an HFD supplemented with 50 mg/kg or 200 mg/kg TP for 8 weeks. The fish were hand-fed 5% of their body weight per day in three feeds, and maintained at 28 ± 1 °C under a 14-h light/10-h dark cycle. The fish in each tank were bulk weighed and counted fortnightly, and the daily feed amount was adjusted accordingly. At the end of the trial, the cumulative survival rate was calculated, and the weight gain and feed conversion ratio were calculated according to the bulk weight of fish in each tank. Tissues were collected from nine fish per diet, their organs were weighed, and biochemical and molecular indices were subsequently measured. HFD-feeding significantly increased lipid deposition, reduced cumulative survival from 96% to 75%, reduced hepatic alkaline phosphate activity (AKP) and serum total antioxidant capacity (T-AOC); and reduced the hepatic expression of immunoglobulin M (IgM), transforming growth factor-beta (TGF-β) and glutathione-S-transferase (GST) genes versus the control diet. The addition of TPs at 50 or 200 mg/kg both ameliorated the HFD-induced increase in lipid droplets in the liver (50 mg/kg TP from 40.83% to 17.27%; 200 mg/kg TP to 25.33%), and increased the cumulative survival rate of the tilapia. The addition of 50 mg/kg TP had a marked effect increasing cumulative survival to 90%, and increasing the activities of serum acid phosphatase (ACP), T-AOC; and IgM, TGF-β, nuclear factor-κB (NF-κB), superoxide dismutase (SOD), and GST gene expression to the highest level of the HFD-fed groups. The 50 mg/kg TP-containing diet also significantly increased the hepatic expression of carnitine palmitoyltransferase 1 alpha (CPT1α) versus the control diet. In contrast, the tilapia fed an HFD supplemented with 200 mg/kg TPs had the lowest expression of adipose triglyceride lipase, hormone-sensitive lipase, CPT1α, fatty acid synthase and acetyl-CoA carboxylase alpha genes of any of the groups, which implies that the lower and higher levels of TP supplementation have differing effects on lipid metabolism. The 200 mg/kg supplement had lower cumulative survival rate (82%), and smaller effects on serum ACP and hepatic AKP activities than the 50 mg/kg dose, and had no significant effect on serum T-AOC or the expression of IgM, TGF-β, GST, or NF-κB genes in the tilapia. These results indicate that the beneficial effects of TPs on the lipid metabolism and health of fish fed an HFD are dose-related. Moreover, they are likely to be largely mediated through lipid catabolism.

Functional identification and characterization of GST genes in the Asian gypsy moth in response to poplar secondary metabolites

The Asian gypsy moth, Lymantria dispar, as one of the most important forest pests in the world, can feed on more than 500 species of host plants, causing serious damage to the forests. Poplar is one of the favorite host plants of L. dispar. The present study aimed to explore the effects of poplar secondary metabolites on the growth and detoxification function of L. dispar larvae. We also aimed to study the expression of glutathione S-transferase (GST) genes in different developmental stages and in response to treatment with secondary metabolites. Six kinds of main secondary metabolites and three groups of characteristic mixed secondary metabolites were selected as follows: Caffeic acid, salicin, rutin, quercetin, catechol, flavone, mixture 1 (salicin and flavone), mixture 2 (salicin, caffeic acid and catechol), and mixture 3 (flavone, caffeic acid and catechol) according to the content changes of secondary metabolites in poplar. The thirteen GST genes were selected as candidate genes to study the expression of GST genes in different developmental stages and after treatment with secondary metabolites using quantitative real-time reverse transcription PCR. The LdGSTe4 and LdGSTo1 genes could be induced by secondary metabolites and were screened to explore their detoxification function against secondary metabolites using RNA interference technology. The results showed that salicin and rutin significantly induced the expression of LdGSTe4 and LdGSTo1. Under the stress of secondary metabolites, LdGSTe4 silencing affected the adaptability of L. dispar larvae to salicin and rutin. LdGSTe4 silencing resulted in a significant decrease in the body weight of L. dispar, but had little effect on the relative growth rate, relative consumption rate, efficiency of conversion of ingested food, efficiency of conversion of digested food, and approximate digestibility, as well as the survival rate and development time. These results provide a deeper understanding of the adaptive mechanism of L. dispar to host plants, form the foundation for the further research into the host resistance mechanism, and identify target genes for breeding resistant transgenic poplar.

Detection of atrazine metabolites in blood serum and liver of mice exposed via their waters to 0, 3 and 30 ppb atrazine.

Atrazine, which is an herbicide used on crops throughout the Midwest, is present in drinking water due to its ability to be carried in runoff from fields. While levels of less than 3 ppb in drinking water is deemed as safe by the USDA, atrazine is often found at much higher levels in nature due to the widespread use of this chemical on fields. Recent studies have identified that atrazine decreases Glutathione-S-transferase (GST) gene hepatic expression when mice are exposed to atrazine in their drinking water. This study investigated if there was a build up of atrazine metabolites in the serum and liver of exposed mice and correlate the species of metabolite amount to the effect it has on gene expression of GST.

Effects of chronic sublethal progestogen exposure on development, reproduction, and detoxification system of water flea, Daphnia magna

The presence of sex steroid hormones in aquatic ecosystems is of rapidly growing concern worldwide since they can affect the different non-target species including cladocerans. Although data are available on the effects of estrogens on the well-established ecotoxicological model organism Daphnia magna, the molecular or behavioural alterations induced by environmentally relevant concentrations (from a few ng L−1 to a few hundred ng L−1 in average) of progestogens have not been investigated on this species. In the present study, we exposed neonates of D. magna to relevant equi-concentrations (1, 10, 100, 500 ng L−1) of mixtures of four progestogens (progesterone, drospirenone, gestodene, levonorgestrel) in short-term (6 days) and long-term (21 days) experiments. Significant alterations were observed at the molecular, cellular, and individual levels. During the short-term exposure, all of the mixtures increased the gene expression of glutathione S-transferase (GST) detoxification enzyme, moreover, the activity of GST was also significantly increased at the concentrations of 10, 100, and 500 ng L−1. In long-term exposure, the number of days until production of the first eggs was reduced at the 10 ng L−1 concentration compared to control, furthermore, the maximum egg number per individual increased at the concentrations of 1 and 10 ng L−1. Based on the authors' best knowledge, this is the first study to investigate the effects of progestogens in mixtures and at environmentally relevant concentrations on D. magna. Our findings contribute to the understanding of the possible physiological effects of human progestogens. Future research should be aimed at understanding the potential mechanisms (e.g., perception) underlying the changes induced by progestogens.

THE EFFECT OF CANTHARIDIN AND ENDOTHALL ON GENE EXPRESSION OF THE KEY REGULATING ENZYMES IN CICHORIUM INTYBUS L.

Background: the underlying mechanisms regulating biosynthesis and the very existence of a cellular system in plants have yet to be clarified to a satisfying point. Aim: this experiment tried to reveal the influence of cantharidin and endothall on gene expression of critical enzymes, glutathione S-transferase, protein phosphatase and, aspartate phosphatase in Cichorium intybus L., an important medicinal plant. Methods: two concentrations of cantharidin and endothall, 2.5 and 10 ?gml-1, were applied on C. intybus seedlings, and the changes in genes evaluated in shoots and roots. Results and Discussion: Cantharidin and endothall-treated seedlings had the lowest expression level of glutathione S-transferase in 2.5 ?gml-1 (0.92±0.11 and 1.07±0.61, respectively) while in 10 ?gml-1, the expression levels were slightly higher. The glutathione S-transferase expression in roots followed a similar trend. The Cantharidin effect on protein phosphatases in shoots and roots of C. intybus followed a similar pattern where the expression level of protein phosphatases in shoots and roots of treated seedlings with 2.5 ?gml-1 (0.51±0.03 and 1.34±0.12, respectively) reduced. At 10 ?gml-1 cantharidin, protein phosphatases' expression markedly increased in both shoots and roots (3.55±0.21 and 3.96±032, respectively). The expression of protein phosphatases in shoots received 2.5 ?gml-1 endothall considerably enhanced (43.21±3.1), whereas its expression was close to zero in roots. The expression of aspartate phosphatases in shoots with cantharidin 2.5 ?gml-1 was almost zero. Whereas in 10 ?gml-1, its expression was radically increased (3.76±0.23). Roots treated with cantharidin indicated high levels of expression, particularly in 10 ?gml-1 (2.07±0.11). Root treated with 2.5 ?gml-1 cantharidin similarly did not express aspartate phosphatases. Seedlings exposed to endothall, the relative expression level of aspartate phosphatases in shoots under 2.5 ?gml-1 was 17.49±1.21 while in roots with 2.5 ?gml-1 was down to 0.45±0.09. Conclusion: It can be reliably expressed that cantharidin and endothall halt plant growth in a dosage-dependent manner by downregulating critical enzymes C. intybus.

Cross-resistance, fitness costs, and biochemical mechanism of laboratory-selected resistance to tenvermectin A in Plutella xylostella.

Tenvermectin A is a new avermectin derivative that has good insecticidal and acaricidal effects. In order to study the resistance of Plutella xylostella to tenvermectin A, a sensitive strain (SS) and a laboratory-selected tenvermectin A-resistant strain (RS, 33.57-fold) were used to evaluate cross-resistance and fitness costs as well as to determine the resistance mechanism. There was no cross-resistance with common pesticides except for moderate cross-resistance with cypermethrin (resistance ratio = 10.26-fold) observed in RS. The activities of metabolic enzymes were measured, and the results showed that mixed function oxidase (MFO) and carboxylate esterase (CarE) in RS increased significantly by 2.92- and 2.86-fold, respectively, compared with SS. In addition, there was no obvious difference in glutathione-S-transferase (GST), which indicated that enhanced MFO and CarE activities may be the main mechanisms of detoxification. In the four typical resistance-related genes, expression of GluCl (4.86-fold), ABCC2 (3.85-fold), and CYP6 (2.94-fold) in RS were significantly promoted, but expression of GST was not. The clone and sequence of the PxGluClα subunit displayed six mutations that could lead to changes in the amino acid residues. High suitability related to tenvermectin A resistance was observed in RS, and it was found that the developmental stages of RS were significantly shortened and the survival rate of females was reduced. In addition, the mechanism of resistance to tenvermectin A may be regulated by the glutamate-gated chloride channel, ATP-binding cassette transporter, and MFO. In general, the study of resistance and biochemical mechanisms can provide beneficial and rational information for the management of resistance in P. xylostella. © 2021 Society of Chemical Industry.