Glutathione S-transferase Activity Research Articles

Toxicological insight of magnetite nanogel: neuro-ethological, hepato-renal, antioxidant, and histopathological traits in Clarias gariepinus

Assessment of acute toxicity of magnetic nanogel (MNG) is crucial to conclude the safe applicable dose and to warrant its application in aquaculture. Therefore, the current study is a novel step to assess behavior, neuro-stress response, hepato-renal, oxidative, and histopathological variations produced by MNG’ acute toxicity in Clarias gariepinus. Two experiments were conducted: the first was a determination of the 96-h lethal concentration 50 (LC50) of MNG in C. gariepinus. Meanwhile, the second was an assessment of the toxicological impacts of three different concentrations of MNG in C. gariepinus following a 10-day exposure period and a subsequent 10-day depuration trial. One hundred and eighty fish were allotted to four groups exposed to 0, 1/10, 1/8, or 1/5 96-h LC50 of MNG. The outcomes exhibited that 96-h LC50 of MNG for C. gariepinus was 44 mg/L. The subjected group to MNG induced a concentration-dependent elevation in the serum values of cortisol, alanine transaminase, aspartate transaminase, urea, and creatinine following MNG exposure. Marked elevation in the oxidative stress indicators (catalase (CAT), glutathione S-transferase activity (GST), and superoxide dismutase (SOD)) was also evident. Meanwhile, the value of the neurological biomarker, acetylcholinesterase (AChE), was markedly reduced in a concentration-dependent way. These biochemical changes were complemented by pathological alterations in the hepato-renal architecture. Interestingly, in response to the 10-day depuration period, most of the tested parameters were eliminated in C. gariepinus exposed to 1/10 of LC50. Conclusively, MNG can induce numerous adverse effects only at higher doses (1/5 and 1/8 of LC50). Meanwhile, the lowest tested concentration of MNG (1/10 of LC50) was safe for application in aquaculture practices with only mild disruptions in the bio-indices. In addition, a retrieval period of 10 days was sufficient to renovate these alterations only in fish exposed to the same concentration.

Diethylhexyl phthalate exposure amplifies oxidant and inflammatory response in fetal hyperglycemia model predisposing insulin resistance in zebrafish embryos.

Exposure of zebrafish embryos to glucose is a suitable model for the fetal hyperglycemia seen in gestational diabetes. Diethylhexyl phthalate (DEHP), which is considered an endocrine-disrupting chemical, is one of the most common phthalate derivatives used in stretching plastic and is encountered in every area where plastic is used in daily life. In the present study, the effects of DEHP on pathways related to insulin resistance and obesity were examined in zebrafish embryos exposed to glucose as a fetal hyperglycemia model. Zebrafish embryos were exposed to DEHP, glucose, and glucose + DEHP for 72 h post-fertilization (hpf), and developmental parameters and locomotor activities were monitored. At 72 hpf ins, lepa, pparγ, atf4a, and il-6 expressions were determined by RT-PCR. Glucose, lipid peroxidation (LPO), nitric oxide (NO) levels, glutathione S-transferase (GST), superoxide dismutase (SOD), and acetylcholine esterase (AChE) activities were measured spectrophotometrically. Compared with the control group, glucose, LPO, GST activity, il6, and atf4a expressions increased in all exposure groups, while body length, locomotor, and SOD activities decreased. While AChE activity decreased in the DEHP and glucose groups, it increased in the glucose + DEHP group. Although glucose exposure increased pparγ and lepa expressions, DEHP significantly decreased the expressions of pparγ and lepa both in the DEHP and glucose + DEHP groups. Our findings showed that DEHP amplified oxidant and inflammatory responses in this fetal hyperglycemia model, predisposing insulin resistance in zebrafish embryos.

Evaluation of the Effects of Alpha-Tocopherol, Quercetin and their Combination on Ethanol-Induced Pancreatic and Duodenal Mucosal injuries: An Experimental Study

Aim: In this study, the effects of alpha-tocopherol (AT), quercetin (QT) or their combination on ethanol-induced pancreatic and duodenal mucosal damage were investigated in rats using morphological and biochemical evaluations.
 Study Design: Experimental study.
 Place and Duration of Study: University of Ibadan, Ibadan, Nigeria.
 Methodology: Ethanol-induced injuries were produced by oral administration of 40% ethanol (0.2 ml/day) for 40 consecutive days, while a control group of rats was served distilled water. Other groups received AT (2.5 mg/kg), QT (50 mg/kg) or their combination with 40% ethanol during the experimental period.
 Results: Blood glucose level was significantly (p<0.05) increased in ethanol-treated rats relative to controls. Ethanol administration caused shrinkage of insulin-secreting islets tissues in the pancreas, while lesions such as erosions, loss of villi and severe inflammatory cell infiltrations of the mucosa and sub-mucosa were observed in the duodenum. These changes were accompanied by significant elevation in the levels of hydrogen peroxide (H2O2), malondialdehyde (MDA) and advanced oxidation protein products (AOPP) in the pancreas and duodenum, along with reduced activities of glutathione peroxidase (GPx) and glutathione S-transferase (GST). Treatment of rats with AT, QT, and especially their combination, yielded profound reversal of ethanol-induced effects indicated by restoration of blood glucose to control levels, preservation of pancreatic and duodenal morphology and the inhibition of ethanol-induced oxidative stress.
 Conclusion: Overall, dietary supplementation with AT and/or QT could potentially counteract the adverse effects associated with chronic alcohol consumption.

Pesticides compromise health: a comparison between lizards collected within and outside an agricultural area.

Reptiles are the least studied vertebrates regarding the impact of pesticides on their health, despite being good models for ecotoxicological studies given their abundance and easy handling. Salvator merianae is widely distributed in South America and often found in agricultural cultivation areas. Here, we compared the morphological, biochemical, and physiological parameters of S. merianae from an exposed area (EA) to pesticides and a reference area (RA) or control. These parameters were measured in plasma (albumin, alanine transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, glucose, total proteins, uric acid, triglycerides, VLDL, and corticosterone) and in erythrocytes (TBARS, glutathione S-transferase, superoxide dismutase, and catalase activity). Blood samples were collected from 28 lizards (EA: three juveniles, three adult females, and three adult males; RA: nine juveniles, four females, and five males) in southern Brazil during the reproductive period. We observed a decrease in body mass, the ratio between body mass and total length and snout-vent length in juvenile lizards collected at EA. The levels of TBARS, glutathione S-transferase, triglycerides, VLDL, and uric acid were altered for juveniles in EA. When comparing the two areas, females differed in superoxide dismutase activity and total proteins, while males differed in superoxide dismutase, catalase, and glutathione S-transferase activity. This set of results shows that S. merianae, especially juveniles, suffers a negative impact when inserted in an agricultural area. The analyzed biomarkers proved suitable for monitoring these lizards and the quality of this environment.

Role of glutathione S-transferases in the mode of action of herbicides that inhibit amino acid synthesis in Amaranthus palmeri

Acetolactate synthase inhibitors (ALS inhibitors) and glyphosate are two classes of herbicides that act by inhibiting an enzyme in the biosynthetic pathway of branched-chain or aromatic amino acids, respectively. Besides amino acid synthesis inhibition, both herbicides trigger similar physiological effects in plants. The main aim of this study was to evaluate the role of glutathione metabolism, with special emphasis on glutathione S-transferases (GSTs), in the mode of action of glyphosate and ALS inhibitors in Amaranthus palmeri. For that purpose, plants belonging to a glyphosate-sensitive (GLS) and a glyphosate-resistant (GLR) population were treated with different doses of glyphosate, and plants belonging to an ALS-inhibitor sensitive (AIS) and an ALS-inhibitor resistant (AIR) population were treated with different doses of the ALS inhibitor nicosulfuron. Glutathione-related contents, GST activity, and related gene expressions (glutamate-cysteine ligase, glutathione reductase, Phi GST and Tau GST) were analysed in leaves. According to the results of the analytical determinations, there were virtually no basal differences between GLS and GLR plants or between AIS and AIR plants. Glutathione synthesis and turnover did not follow a clear pattern in response to herbicides, but GST activity and gene expression (especially Phi GSTs) increased with both herbicides in treated sensitive plants, possibly related to the rocketing H2O2 accumulation. As GSTs offered the clearest results, these were further investigated with a multiple resistant (MR) population, compressing target-site resistance to both glyphosate and the ALS inhibitor pyrithiobac. As in single-resistant plants, measured parameters in the MR population were unaffected by herbicides, meaning that the increase in GST activity and expression occurs due to herbicide interactions with the target enzymes.

Long-term impact of rearing substrates on susceptibility to insecticides and metabolic enzyme activities in the house fly Musca domestica.

Musca domestica Linnaeus is a devastating insect pest of medical and veterinary importance with reports of resistance development to commonly used insecticides worldwide. Rearing substrates usually play a crucial role in determining susceptibility to insecticides and control of insect pests. The aim of the present study was to investigate the effect of five rearing substrates of M. domestica on its susceptibility to different insecticides and activities of metabolic enzymes. After 30 generations of rearing, susceptibility of M. domestica to tested insecticides, viz., malathion, pirimiphos-methyl, alpha-cypermethrin, deltamethrin, methomyl, propoxur, spinetoram, and chlorfenapyr had evident differences. Musca domestica reared on hen liver exhibited reduced susceptibility to all insecticides followed by the strain reared on poultry manure. However, M. domestica reared on milk-based diet showed the highest susceptibility to tested insecticides followed by the strain reared on manures of buffalo and horse. In addition, M. domestica reared on different substrates exhibited significant differences (p < 0.01) in the activities of glutathione S-transferase (GST), cytochrome P450-dependent monooxygenase, and carboxylesterase (CarE). Overall, hen liver and poultry manure strains exhibited higher activities of metabolic enzymes than those of the milk-based diet, buffalo, and horse manure strains. In conclusion, the data of the present study exhibited a significant effect of rearing substrates on the susceptibility to insecticides and activities of metabolic enzymes in M. domestica. These results could be helpful for the sustainable management of M. domestica on different hosts by selecting appropriate insecticides.

Senolytics prevent age-associated changes in female mice brain

PurposeConsidering that the combination of dasatinib and quercetin (D + Q) demonstrated a neuroprotective action, as well as that females experience a decline in hormonal levels during aging and this is linked to increased susceptibility to Alzheimer’s disease, in this study we evaluated the effect of D + Q on inflammatory and oxidative stress markers and on acetylcholinesterase and Na+, K+-ATPase activities in brain of female mice. MethodsFemale C57BL/6 mice were divided in Control and D (5 mg/kg) + Q (50 mg/kg) treated. Treatment was administered via gavage for three consecutive days every two weeks starting at 30 days of age. The animals were euthanized at 6 months of age and at 14 months of age. ResultsResults indicate an increase in reactive species (RS), thiol content and lipid peroxidation followed by a reduction in nitrite levels and superoxide dismutase, catalase and glutathione S-transferase activity in the brain of control animals with age. D+Q protected against age-associated increase in RS and catalase activity reduction. Acetylcholinesterase activity was increased, while Na+, K+-ATPase activity was reduced at 14 months of age and D+Q prevented this reduction. ConclusionThese data demonstrate that D+Q can protect against age-associated neurochemical alterations in the female brain.

Nondestructive Evaluation of Metal Bioaccumulation and Biochemical Biomarkers in Blood of Broad-Snouted Caiman (Caiman latirostris) from Northeastern Brasil.

Studies on the bioaccumulation and toxicity of contaminants in Crocodylians are scarce. We evaluated alterations in concentrations of the nondestructive biomarkers butyrylcholinesterase (BChE), glutathione-S-transferase (GST), superoxide dismutase (SOD), and reduced glutathione (GSH), together with bioaccumulation of the metals iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), chronium (Cr), aluminium (Al), and lead (Pb) in Caiman latirostris captured in Tapacurá Reservoir (TR; São Lourenço da Mata, Pernambuco, Brasil), in urbanized areas of Pernambuco State (UA; Brasil) and from the AME Brasil caiman farm (AF; Marechal Deodoro, Alagoas, Brasil); the latter was used as a potential reference with low levels of contamination. For metal analysis, 500 µL of blood was digested in 65% HNO3 and 30% H2O2. The samples were analyzed by inductively coupled plasma-optical emission spectrometry. For analysis of biomarkers, an aliquot of blood was centrifuged to obtain plasma in which biochemical assays were performed. Blood concentrations of metals analyzed in animals from AF were lower compared with TR and UA, confirming that animals from the caiman farm could be used as references with low levels of contamination. Iron, Cu, Mn, Al, and Pb exceeded toxic levels for other vertebrates in animals from TR and UA. Butyrylcholinesterase activity showed significant reduction in adults from UA and TR compared with AF. An increase in the activity of GST and GSH, in adults of TR and UA in relation to AF, was verified. Superoxide dismutase activity showed a significant reduction in adults of TR in relation to AF, and the concentrations of Cu and Mn were negatively correlated with SOD activity. Animals from UA and TR showed greater concentrations of the analyzed metals compared with reference animals, and changes in biomarkers were seen, confirming the potential of these nondestructive chemical and biological parameters in blood of C. latirostris for biomonitoring of pollution. Environ Toxicol Chem 2024;43:878-895. © 2024 SETAC.

Diet with optimal glutathione supplement improves growth, nonspecific immunity, intestinal microbiota, and antioxidant ability in Micropterus salmoides.

In this study, Micropterus salmoides were fed with dietary glutathione (GSH, 0, 100, 300, and 500 mg/kg) for 56 days to investigate its effects on growth performance, serum nonspecific immunity, liver antioxidant capacity, tissue morphology, and intestinal microbiota. The results showed that the survival rate, weight gain rate, and specific growth rate and condition factor increased, whereas the feed conversion ratio, hepato-somatic index, and viscerosomatic index decreased in the GSH groups. Compared with the control group, the serum total protein content significantly increased, whereas the triglyceride and total cholesterol significantly decreased in the 300-mg/kg dietary GSH group. The activities of lysozyme, alkaline phosphatase, and acid phosphatase were significantly higher in GSH-supplemented groups, peaking at 300-mg/kg GSH. GSH supplementation significantly increased total antioxidant capacity and decreased malondialdehyde content, with the most pronounced effects at 300-mg/kg GSH. Further antioxidant indicators showed that a dietary supplement of 300-mg/kg GSH significantly increased the activities of superoxide dismutase, glutathione transferase, endogenous glutathione, glutathione reductase, and catalase. At 300-mg/kg GSH, the liver exhibited improved characteristics with alleviated vacuolation and hepatocyte nuclear shift, and intestine showed enhanced structure with increased villus height and intestinal wall thickness. Additionally, a 300-mg/kg GSH supplementation improved the diversity of intestinal microbiota, increased the abundance of probiotics such as Bacillus, and inhibited the development of pathogenic bacteria such as Plesiomonas. Overall, the results suggest that the effect of GSH addition on improving growth performance, nonspecific immunity, antioxidant capacity, and intestinal microbiota of M. salmoides is best in the 300-mg/kg addition group. Based on second-degree polynomial regression analysis of weight gain, the optimum requirement of dietary GSH in M. salmoides is a 336.84-mg/kg diet.

Interactive effects of bismuth exposure (water and diet) and temperature on snail fatty acid composition, antioxidant enzymes and lipid peroxidation

Despite the growing prevalence of Bismuth (Bi), very little research has been carried to assess its potential toxic effects on aquatic organisms. This study aimed to address this gap by investigating the interactive effects of Bi exposure and elevated temperature on freshwater snails of the genus Lymnaea, specifically on their fatty acid (FA) profiles, oxidative stress markers (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST)) and lipid peroxidation (malondialdehyde (MDA) content). Bismuth exposure was introduced through two distinct routes: i) food via Bi-exposed biofilm (grown under 2 μM Bi), and ii) water (2 μM Bi). Exposed snails were maintained at two temperatures, 19°C and 25°C, over a duration of 14 days. Bismuth bioaccumulation occurred in Bi-exposed biofilm concurrently with a pronounced increase in polyunsaturated fatty acids (PUFA), likely as a protective mechanism to preserve cell structure and integrity. Bismuth bioaccumulation also occurred in snails with their FA composition largely reflecting the composition of their dietary source highlighting the direct link between diet and snail FA profiles. Additionally, the antioxidant enzymes studied exhibited diverse responses under Bi exposure and thermal stress, suggesting the induction of oxidative stress in snails. SOD activity increased at 25°C, suggesting a thermal stress. CAT activity remained high under all conditions, unaffected by temperature or Bi exposure. GPx levels increased in snails fed with Bi-laden biofilm, particularly at 19°C. GST activity showed great variability with a significant three-way interaction. The observed elevation in MDA levels among Bi-exposed snails suggested a potential deficiency in their antioxidant enzyme systems, leading to an increased susceptibility to lipid peroxidation. This research highlights the complex interaction between Bi contamination, temperature, and the physiological responses of aquatic organisms, and reveals the need for future research into the environmental impact of Bi in aquatic ecosystems. We further highlight the importance of food for Bi transfer to higher consumers and the importance of considering dietborne exposures in ecotoxicological studies.

The symbiont Wolbachia alleviates pesticide susceptibility in the two-spotted spider mite Tetranychus urticae through enhanced host detoxification pathways.

The two-spotted spider mite (Tetranychus urticae) is one of the most well-known pesticide-resistant agricultural pests, with resistance often attributed to changes such as target-site mutations and detoxification activation. Recent studies show that pesticide resistance can also be influenced by symbionts, but their involvement in this process in spider mites remains uncertain. Here, we found that infection with Wolbachia, a well-known bacterial reproductive manipulator, significantly increased mite survival after exposure to the insecticides abamectin, cyflumetofen, and pyridaben. Wolbachia-infected (WI) mites showed higher expression of detoxification genes such as P450, glutathione-S-transferase (GST), ABC transporters, and carboxyl/cholinesterases. RNA interference experiments confirmed the role of the two above-mentioned detoxification genes, TuCYP392D2 and TuGSTd05, in pesticide resistance. Increased GST activities were also observed in abamectin-treated WI mites. In addition, when wild populations were treated with abamectin, WI mites generally showed better survival than uninfected mites. However, genetically homogeneous mites with different Wolbachia strains showed similar survival. Finally, abamectin treatment increased Wolbachia abundance without altering the mite's bacterial community. This finding highlights the role of Wolbachia in orchestrating pesticide resistance by modulating host detoxification. By unraveling the intricate interplay between symbionts and pesticide resistance, our study lays the groundwork for pioneering strategies to combat agricultural pests.

Personal care products: an emerging threat to the marine bivalve Ruditapes philippinarum

In the last few decades, there has been a growing interest in understanding the behavior of personal care products (PCPs) in the aquatic environment. In this regard, the aim of this study is to estimate the accumulation and effects of four PCPs within the clam Ruditapes philippinarum. The PCPs selected were triclosan, OTNE, benzophenone-3, and octocrylene. A progressive uptake was observed and maximum concentrations in tissues were reached at the end of the exposure phase, up to levels of 0.68 µg g−1, 24 µg g−1, 0.81 µg g−1, and 1.52 µg g−1 for OTNE, BP-3, OC, and TCS, respectively. After the PCP post-exposure period, the removal percentages were higher than 65%. The estimated logarithm bioconcentration factor ranged from 3.34 to 2.93, in concordance with the lipophobicity of each substance. No lethal effects were found although significant changes were observed for ethoxyresorufin O-demethylase activity, glutathione S-transferase activity, lipid peroxidation, and DNA damage.

Effect of acute cadmium exposure on oxidative stress and antioxidant system of the scallop Aequipecten tehuelchus

This study aimed to assess the impact of acute exposure (96 h) to Cd in gills, digestive gland and muscle of the Tehuelche scallop Aequipecten tehuelchus from San José gulf in Patagonia, Argentina. Scallops were exposed to Cd concentrations of 0, 25, 50, 100, 150, 204, 275, 371, and 500 μg/L, and mortality rates were recorded after 96 h of exposure. Surviving organisms were analyzed for the biochemical response through reactive oxygen and nitrogen species (RONS), activities of catalase (CAT) and glutathione-S-transferase (GST), metallothioneins (MT), lipid peroxidation (LPO) and liposoluble antioxidants α-tocopherol (α-T) and β-carotene (β-C). The mean lethal concentration (LC50) was 155.8 μg Cd/L, a lower value than other scallops' species, showing that A. tehuelchus has a particular sensitivity to Cd. In the three tissues, at all exposure concentrations, there was no significant response in RONS levels, GST activity or LPO. Nevertheless, CAT activity and α-T levels decreased in the gills but increased in the digestive gland, with no significant response in the muscle. Two-way ANOVA revealed a significant interaction between Cd concentration and tissue on MT, which increased significantly in gills, decreased in digestive gland with 100 compared to 50 μg Cd/L; whereas in muscle a significant increase was observed with 25 μg Cd/L compared to control. The results show a significant effect of Cd in scallop's gills on CAT activity and α-T levels, highlighting this tissue as the primary target against relevant concentrations of metal in seawater. The effect on digestive gland and muscle was minimal. The overall results suggest that Cd toxicity is tissue-specific. This study will help reduce the existence knowledge gap regarding potential impacts of acute exposure to Cd in a bivalve species with high ecological and commercial importance, as well as identifying the most responsive biomarkers associated with Cd stress for monitoring assessment.

Glutathione S-transferase activity facilitates rice tolerance to the barnyard grass root exudate DIMBOA

BackgroundIn paddy fields, the noxious weed barnyard grass secretes 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) to interfere with rice growth. Rice is unable to synthesize DIMBOA. Rice cultivars with high or low levels of allelopathy may respond differently to DIMBOA.ResultsIn this study, we found that low concentrations of DIMBOA (≤ 0.06 mM) promoted seedling growth in allelopathic rice PI312777, while DIMBOA (≤ 0.08 mM) had no significant influence on the nonallelopathic rice Lemont. DIMBOA treatment caused changes in the expression of a large number of glutathione S-transferase (GST) proteins, which resulting in enrichment of the glutathione metabolic pathway. This pathway facilitates plant detoxification of heterologous substances. The basal levels of GST activity in Lemont were significantly higher than those in PI312777, while GST activity in PI312777 was slightly induced by increasing DIMBOA concentrations. Overexpression of GST genes (Os09g0367700 and Os01g0949800) in these two cultivars enhanced rice resistance to DIMBOA.ConclusionsTaken together, our results indicated that different rice accessions with different levels of allelopathy have variable tolerance to DIMBOA. Lemont had higher GST activity, which helped it tolerate DIMBOA, while PI312777 had lower GST activity that was more inducible. The enhancement of GST expression facilitates rice tolerance to DIMBOA toxins from barnyard grass root exudates.

Developmental iron exposure induces locomotor alterations in Drosophila: Exploring potential association with oxidative stress

Prenatal iron (Fe) exposure has been associated with learning and cognitive impairments, which may be linked to oxidative stress resulting from elevated Fe levels and harm to the vulnerable brain. Drosophila melanogaster has contributed to our understanding of molecular mechanisms involved in neurological conditions. This study aims to explore Fe toxicity during D. melanogaster development, assessing oxidative stress and investigating behaviors in flies that are related to neurological conditions in humans. To achieve this goal, flies were exposed to Fe during the developmental period, and biochemical and behavioral analyses were conducted. The results indicated that 20 mM Fe decreased fly hatching by 50 %. At 15 mM, Fe exposure increased lipid peroxidation, and GSH levels decreased starting from 5 mM of Fe. Superoxide Dismutase activity was enhanced at 15 mM, while Glutathione S-Transferase activity was inhibited from 5 mM. Although chronic Fe exposure did not alter acetylcholinesterase (AChE) activity, flies exhibited reduced locomotion, increased grooming, and antisocial behavior from 5 mM of Fe. This research highlights potential Fe toxicity risks during development and underscores the utility of D. melanogaster in unraveling neurological disorders, emphasizing its relevance for future research.

Investigation of crude methanolic extract from poison secreted by the Rhaebo gutattus on status redox antioxidant in mice

The study evaluated the antioxidant properties of a crude methanolic extract (CME) from Rhaebo guttatus poison in mice over a period of 7 and 30 days. The mice were divided into groups and treated with different concentrations of the extract (0; 8 μg mL-1; 16 μg mL-1 and 32 μg mL-1 or vehicle; 100 μL/animal/day; via gavage). The liver samples were analyzed for status redox parameters as catalase (CAT), glutathione-S-transferase (GST), reduced glutathione (GSH) and thiobarbituric acid reactive substances (TBARS). The results showed that the CME caused changes in the levels of various antioxidants and oxidative stress markers. At 7 days, there was an increase in TBARS levels (8 μg mL-1 dose) and GST activity (16 μg mL-1 dose), and a reduction in GSH levels (32 μg mL-1 dose) compared to the control group. At 30 days, TBARS and GSH levels returned to control values in the same period, but GSH increased (32 μg mL-1 dose) compared at 7 days; GST activity remained high after 30 days for 32 μg mL-1 dose compared other groups and time of treatment (7 days). Overall, the study suggests that the extract modulates antioxidant properties per se that can affect various markers of status redox in the liver of mice, mainly 16 μg mL-1 dose demonstrated to act under antioxidant enzymes in different times (7 or 30 days).

Pyroxasulfone Metabolism in Resistant Lolium rigidum: Is It All Down to GST Activity?

Resistance to the herbicide pyroxasulfone has slowly but steadily increased in agricultural weeds. The evolved resistance of one Lolium rigidum population has been attributed to the conjugation of pyroxasulfone to reduced glutathione, mediated by glutathione transferase (GST) activity. To determine if GST-based metabolism is a widespread mechanism of pyroxasulfone resistance in L. rigidum, a number of putative-resistant populations were screened for GST activity toward pyroxasulfone, the presence of GSTF13-like isoforms (previously implicated in pyroxasulfone conjugation in this species), tissue glutathione concentrations, and response to inhibitors of GSTs and oxygenases. Although there were no direct correlations between pyroxasulfone resistance levels and these individual parameters, a random forest analysis indicated that GST activity was of primary importance for L. rigidum resistance to this herbicide.

Ecotoxicological responses of juvenile Sparus aurata to BDE-99 and BPA exposure: A multi-biomarker approach integrating immune, endocrine and oxidative endpoints

Pentabromodiphenyl ether (BDE-99) and bisphenol A (BPA) are synthetic organic compounds present in several daily use products. Due to their physicochemical properties, they are ubiquitously present in aquatic ecosystems and considered highly persistent. Recent evidence has confirmed that both emerging compounds are toxic to humans and terrestrial mammals eliciting a wide range of detrimental effects at endocrine and immune levels. However, the ecotoxicological responses that they can trigger in vertebrate marine species have not yet been established. Hence, this study aimed to investigate the ecotoxicological responses of juvenile Sparus aurata upon chronic (28 days) dietary exposure to BDE-99 and BPA (alone and combined) following an integrated multi-biomarker approach that combined fitness indicators (Fulton's K and splenosomatic indexes) with endocrine [cortisol, 17β-estradiol (E2), 11-ketotestosterone (11-KT) concentrations] and immune (peroxidase and antiprotease activities) endpoints in fish plasma, and oxidative stress [superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) activities, and lipid peroxidation (LPO)] endpoints in the fish spleen. The mixture of BDE-99 and BPA yielded the highest IBR index value in both plasma and spleen biomarkers, therefore, suggesting that the effects of these compounds are more severe when they act together. Endocrine biomarkers were the most responsive in the three contaminated treatments. Fitness indicators were not affected by the individual nor the interactive effects of BDE-99 and BPA. These findings highlight the relevance of accounting for the interactive effects of emerging chemical contaminants and integrating responses associated with distinct biological pathways when investigating their impacts on marine life, as such a multi-biomarker approach provides a broader, more realistic and adequate perspective of challenges faced by fish in a contaminated environment.

Confirmation and differential metabolism associated with quinclorac resistance in smooth crabgrass (Digitaria ischaemum)

AbstractQuinclorac controls crabgrass (Digitaria spp.) in cool- and warm-season turfgrass species. Herbicide-resistant smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] biotypes have evolved due to recurrent usage of quinclorac. Two Mississippi populations (MSU1 and MSU2) of D. ischaemum were characterized using standard greenhouse dose–response screens to assess their resistance relative to known susceptible populations. Subsequent investigations explored mechanisms of resistance, including examining cyanide accumulation, glutathione S-transferase (GST) activity, and the potential involvement of cytochrome P450s in MSU1, MSU2, and a susceptible (SMT2). Resistant populations MSU1 and MSU2 required 80 and 5 times more quinclorac, respectively, to reach 50% biomass reduction than susceptible populations. The SMT2 biotype accumulated three times more cyanide than the resistant MSU1 and MSU2 populations. GST activity was elevated in resistant MSU1 and MSU2 populations. Furthermore, quinclorac concentrations in treated resistant populations were elevated when plants were pretreated with the P450 inhibitor malathion. These findings suggest a non–target site based mechanism of resistance involving the accumulation of cyanide. This may provide a scientific basis for understanding the occurrence of quinclorac-resistant D. ischaemum, although further research is needed to investigate potential target-site mechanisms of resistance.

Evaluation of the Anti-Inflammatory and Antioxidant Potential of Cymbopogon citratus Essential Oil in Zebrafish.

This study explored the protective capacity of the essential oil (EO) of Cymbopogon citratus against oxidative stress induced by hydrogen peroxide (H2O2) and the inflammatory potential in zebrafish. Using five concentrations of EO (0.39, 0.78, 1.56, 3.12, and 6.25 μg/mL) in the presence of 7.5 mM H2O2, we analyzed the effects on neutrophil migration, caudal fin regeneration, cellular apoptosis, production of reactive oxygen species (ROS), and activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) after 96 h of exposure. A significant decrease in neutrophil migration was observed in all EO treatments compared to the control. Higher concentrations of EO (3.12 and 6.25 μg/mL) resulted in a significant decrease in caudal fin regeneration compared to the control. SOD activity was reduced at all EO concentrations, CAT activity significantly decreased at 3.12 μg/mL, and GST activity increased at 0.78 μg/mL and 1.56 μg/mL, compared to the control group. No significant changes in ROS production were detected. A reduction in cellular apoptosis was evident at all EO concentrations, suggesting that C. citratus EO exhibits anti-inflammatory properties, influences regenerative processes, and protects against oxidative stress and apoptosis.