Glutathione S-transferase Enzyme Activity Research Articles

Effect of lipoic acid supplementation on gene expression and activity of glutathione S-transferase enzyme in infertile men

Oxidative stress has become the focus of interest as a potential cause of male infertility. We evaluate effects of lipoic acid (LA) supplementation on glutathione S-transferase (GST) expression. This randomized, triple-blind, placebo-controlled clinical trial was conducted on 44 infertile males with idiopathic asthenozoospermia. Men were randomized to receive 600 mg LA or placebo once daily for 12 weeks and semen samples and venous blood samples were obtained. GST expression, reactive oxygen species (ROS) levels, GST activity and reproductive hormone profiles were also measured. GST expression in the intervention group were significantly higher than the control group. Also, at the end of the study, GST activity increased, and ROS levels decreased significantly compared to the baseline. Additionally, the intervention group showed an increase in testosterone and decrease in serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin after 12 weeks, but this difference was not significant. We conclude a 12-week treatment with LA leads to improvements in reproductive hormones in serum, and significantly reduces the generation of ROS and increases the gene expression and activity of GST in seminal fluid.

Effects of phenol on glutathione S-transferase expression and enzyme activity in Chironomus kiiensis larvae.

Detoxifying enzyme mRNAs are potentially useful stress biomarkers. Glutathione S-transferase (GST) metabolises lipophilic organic contaminants and mitigates oxidative damage caused by environmental pollutants. Herein, 12 Chironomus kiiensis GSTs (CkGSTs1-6, CkGSTt1-2, CkGSTd1-2, CkGSTm1-2) were cloned and grouped into sigma, theta, delta and microsomal subclasses. Open reading frames (450-699 bp) encode 170-232 amino acid proteins with predicted molecular masses of 17.31-26.84 kDa and isoelectric points from 4.94 to 9.58. All 12 GSTs were expressed during all tested developmental stages, and 11 displayed higher expression in fourth-instar larvae than eggs. GST activity after 24 h of phenol exposure was used to estimate environmental phenol contamination. After exposure to sublethal concentrations of phenol for 48 h, expression and activity of CkGSTs were inhibited in C. kiiensis larvae. Expression of CkGSTd1-2 and CkGSTs1-2 varied with phenol concentration, indicating potential use as biomarkers for monitoring environmental phenol contamination.

Investigation of the Polyphenol Composition, Biological Activities, and Detoxification Properties of Some Medicinal Mushrooms from Turkey.

Ethanolic extracts of the mushroom species Ganoderma adspersum, Inonotus hispidus, Russula chloroides, and Sarcodon imbricatus were investigated for their polyphenolic contents and biological activities. The radical scavenging activity of the extracts was evaluated by 2,2-diphenyl-1-(2,4,6-trinitrophenyl) (DPPH) method and their polyphenolic compounds were determined by high performance liquid chromatography (HPLC) analysis. Furthermore, the activity effects of mushroom extracts on the enzyme glutathione-S-transferase (GST) were also examined. Additionally, the antimicrobial activity of mushroom extracts was evaluated by disc diffusion method. Ethanolic extract of I. hispidus demonstrated the highest total phenolic content and total flavonoid contents, with 227.23±4.96 mg gallic acid equivalent/g and 42.14±0.20 quercetin equivalent/g, respectively. The highest DPPH radical scavenging activity was observed for ethanolic extracts of I. hispidus, with 10.687±1.643 µg/mL IC50. HPLC analysis demonstrated that R. chloroides was composed of ferulic acid, gallic acid, and myricetin compounds. The highest GST enzyme activity effect was detected with the ethanol extracts of I. hispidus and S. imbricatus. None of the mushroom extracts demonstrated significant inhibition of the bacterial strains used. These results indicate that I. hispidus may be proposed as a new potential source of natural medicine and its potential may be related to its polyphenolic content, which needs further investigation.

Effect of volatiles produced by Trichoderma spp. on expression of glutathione transferase genes in Sclerotinia sclerotiorum

This study was carried out to determine the effect of volatile compounds produced from different Trichoderma spp. against different biological parameters of S. sclerotiorum. The results showed that volatiles of all tested Trichoderma spp. including T. reesei, T. ceramicum, T. rossicum, T. longibrachiatum, T. atroviride, T. viridescens, T. hamatum, T. harzianum, T. virens, T. koningii and T. koningiopsis were able to markedly reduce mycelial growth, sclerogenesis as well as mycelial and carpogenic germination of the sclerotia. The exposure of pathogen mycelium to volatiles of T. ceramicum, T. atroviride, T. viridescens, T. virens, T. koningii and T. koningiopsis for 24 h up-regulated four potential glutathione S-transferase (GST) genes including SS1G_10295.1, SS1G_00703.1, SS1G_01918.1 and SS1G_07195.1. In SS1G_07319.1, the volatiles of Trichoderma spp. did not show any effect on expression of the GST genes. In addition, enzyme activity of GST was determined with 1-chloro-2, 4-dinitrobenzene as substrate. While enzymatic activity was 42.5 units mg−1 protein in the control, it was recorded as 79.4, 89.3, 85.1, 88.9, 88.7 and 87.5 units mg−1 protein for volatiles of T. ceramicum, T. atroviride, T. viridescens, T. virens, T. koningiopsis and T. koningii, respectively.

Detoxification of host plant phenolic aglycones by the spruce budworm.

This study examines the post-ingestive fate of two host-plant derived small-molecule phenolics (the acetophenones piceol and pungenol) that have previously been shown to be toxic to the outbreaking forest pest, spruce budworm (Choristoneura fumiferana). We test first whether these compounds are transformed during passage through the midgut, and second whether the budworm upregulates activity of the detoxification enzyme glutathione-s-transferase (GST) in response to feeding on these compounds. Insects were reared on either foliage or artificial diet to the fourth instar, when they were transferred individually to one of two treatment diets, either control or phenolic-laced, for approximately 10 days, after which midguts were dissected out and used for Bradford soluble protein and GST enzyme activity analysis. Frass was collected and subjected to HPLC-DAD-MS. HPLC showed that the acetophenones do not autoxidize under midgut pH conditions, but that glucose- and glutathione- conjugates are present in the frass of insects fed the phenolic-laced diet. GST enzyme activity increases in insects fed the phenolic-laced diet, in both neutral pH and alkaline assays. These data show that the spruce budwom exhibits counter-adaptations to plant phenolics similar to those seen in angiosperm feeders, upregulating an important detoxifying enzyme (GST) and partially conjugating these acetophenones prior to elimination, but that these counter-measures are not totally effective at mitigating toxic effects of the ingested compounds in the context of our artifical-diet based laboratory experiment.

Phthalate induced oxidative stress and DNA damage in earthworms (Eisenia fetida)

Phthalates (phthalic acid esters) have been widely applied as plasticizers. They are ubiquitous contaminants in soils, thereby posing a threat to human health. In this study, ecotoxicological effects of three typical PAEs (dimethyl phthalate-DMP, di-n-octyl phthalate-DOP and butyl benzyl phthalate-BBP) were investigated. As a biological indicator, earthworms (Eisenia fetida) were exposed to phthalates at various doses (0, 0.1, 1, 10 and 50 mg/kg) for different times (7, 14, 21, and 28 d). We evaluated the effects of phthalates on reactive oxygen species (ROS) generation, antioxidant enzymes (superoxide dismutase-SOD, peroxidase-POD and catalase-CAT) activities, glutathione S-transferase enzyme (GST) activity, malondialdehyde (MDA) content and DNA damage. Results showed that ROS content increased with increasing phthalates, whereas ROS content generally increased and then decreased with exposure time. However, antioxidant enzymes activities in earthworms displayed different trends. The GST activity in high-dose treatment group was significantly activated. For DMP and DOP, lipid peroxidation mainly occurred between 14 and 28 d, while for BBP, it primarily existed after 7 d and then disappeared after 28 d. Besides, comet assay indicated that there was a dose-response relationship between the DNA damage and phthalate dose, following DMP > DOP > BBP. Given their toxicity, it is important to understand the mechanisms associated with their eco-toxicity and to reduce their adverse impacts on the environment.

Assessment of triclosan impact on enzymatic biomarkers in an Indian major carp, Catla catla

BackgroundThe present study was designed to determine the median lethal concentration (96-h LC50) of triclosan (TCS) and to investigate the effect of a sublethal concentrations of TCS on the activities of glutamic oxaloacetic transaminases (GOT), glutamic pyruvic transaminases (GPT), and glutathione S-transferase (GST) in the gill, liver, and muscle of an Indian major carp Catla catla.ResultsIn this study, static renewal procedure was followed to determine the 96 LC50 value. The results indicated that the 96-h LC50 of TCS for C. catla was 0.36 mg L−1. 1/10th, 1/25th, and 1/50th of 96-h LC50 value (0.036, 0.014, 0.007 mg L−1) were selected for sublethal studies, and the fish were examined every 5 days for 20 days. The results indicated that TCS exposure to fish at three different sublethal concentrations significantly (p < 0.05, p < 0.01) enhanced GOT, GPT, and GST enzyme activity in all the tissues with increased dose and exposure period.ConclusionProlonged exposure (20 days) to TCS at sublethal concentrations induces severe physiological alterations in Catla catla, and these biomarkers can be used as a mechanistic tool for evaluating the toxicity-derived alterations in fish.

Evaluation of amino acid contents and enzyme activities of seeds from Semillon and Carignane wine grape cultivars grown under different irrigation conditions

The effects of deficit irrigations (DI50, DI75) and full irrigation (FI100) level together with control (Rainfed) treatment on amino acid contents and enzyme activities of seeds of Semillon and Carignane wine grape varieties were evaluated. Irrigation was started when the midday leaf water potential reached -10 bars. Accordingly, irrigation was initiated after berry set and continued at weekly intervals until the harvest time in the study area. To calculate of water volumes applied to the irrigated plots were considered 50%, 75% and 100% of the cumulative evaporation from the Class A Pan for a week duration. The results of this study showed that irrigation affected the phytochemical parameters in both cultivars. In terms of glutathione S-transferase enzyme activity and amino acid contents (except aspartate), Semillon gave higher values than those of Carignane. However, values of glutathione and catalase enzyme activities, quaternary amines and aspartate amino acids were higher in Carignane. Phytochemical contents of the seeds changed according to the irrigation levels. Generally, the values of quaternary amines, dehydrins and histidine, cystine, lysine, proline in amino acids considerably increased in the control and DI50 treatments. However, there were no significance differences in terms of amino acids (glutamine, glycine, thionine, arginine, hydroxy proline and sarcosine) among the irrigation levels. As a result of the study, it can be concluded that the amounts of compounds analyzed in the grape seeds increased with rainfed and deficit irrigation together with the rainfall under experimental conditions.

Adverse effects, expression of defense-related genes, and oxidative stress-induced MAPK pathway in the benzo[α]pyrene-exposed rotifer Brachionus rotundiformis

To examine the adverse effects of the benzo[α]pyrene (B[α]P), the monogonont rotifer Brachionus rotundiformis was exposed to various concentration of B[α]P (0 [control], 1, 10, and 100 μg/L) and measured life cycle parameters (e.g., mortality, fecundity [cumulated number of offspring], and lifespan), reactive oxygen species (ROS), antioxidant enzymatic activity of glutathione S-transferase (GST). In addition, defense-related transcripts (e.g., glutathione S-transferases [GSTs], ATP binding cassette [ABCs] transporters) and Western blot analysis of mitogen-activated protein kinase (MAPK) signaling pathway were investigated in B[α]P-exposed rotifer. In this study, the total intracellular ROS level and GST activity were significantly increased (P < 0.05), while fecundity and lifespan were also significantly (P < 0.05) reduced in a concentration dependent manner in B[α]P-exposed B. rotundiformis. In addition, transcriptional regulation of GSTs and ABC transporters were significantly upregulated and downregulated (P < 0.05), respectively, suggesting that B[α]P can induce oxidative stress leading to induction of antioxidant system and detoxification mechanism. In addition to detoxification-related genes, B[α]P-exposed B. rotundiformis showed the increased levels of the p-JNK and p-p38, suggesting that B[α]P can activate MAPK signaling pathway in B. rotundiformis.

Acetylcholinesterase, Butyrylcholinesterase and Glutathione S-Transferase Enzyme Activities and Their Correlation with Genotypic Variations Based on GST M1 and GST T1 Loci in Long Term-Pesticide-Exposed Tea Garden Workers of Sub-Himalayan West Bengal

Organophosphates (OPs) and carbamates (CBs) are known to reduce acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) and increase Glutathione S-Transferase (GST) activities in the exposed individuals. We have evaluated AChE, BChE and GST activities in long-term pesticide exposed tea garden workers of sub-Himalayan West Bengal and tried to relate enzyme activities with polymorphisms in GST M1 and GST T1 genes. Enzyme activities were measured spectro-photometrically in blood samples of sprayers and pluckers in relation to age-matched control individuals. Allele-specific multiplex-PCR was employed to score the presence of GST M1 and GST T1 alleles. Significantly lower (p < 0.01) level of AChE and BChE activities were found in the worker group (3.15 ± 0.69 µmol/min/mL of lysate and 1.2 ± 0.54 µmol/min/mL of plasma respectively) compared to the control group (3.74±0.26 µmol/min/mL of lysate and 2.21 ±0.27 µmol/min/mL of plasma respectively). Whereas, significantly higher (p < 0.01) level of GST activity was detected in the worker group (3.83 ±0.97 lU/gm of Hb) comprising of 61 individuals compared to control group (2.47 ±0.29 lU/gm of Hb) comprising of equal number of individuals. Out of total 122 individuals, 34.43% had both GST M1 and GST T1, 23.77% had single-null genotype for GST T1, 27.05% had the single-null genotype for GST M1 and 14.75% individuals had double-null genotypes. We found no significant difference in enzyme activities among the four genotypes when test and control groups were compared. This study for the first time explored changes in AChE, BChE and GST activities in tea garden workers exposed chronically to OPs and CBs in the studied region. Our study indicated that exposure to OP and CB pesticides leads to changes in AChE, BChE and GST activities and the presence or absence of GST M1 and GST T1 alleles are possibly not related to the changes in AChE, BChE and GST activities.

Glutathione S-transferase enzyme activity and protein expression in patients with recurrent tonsillitis and idiopathic tonsillar hypertrophy.

The palatine tonsil is a significant part of the secondary immune system. Tonsillitis and idiopathic tonsillar hypertrophy (ITH) are the most common pathologies of this component. Although there are studies on their pathogenesis, there is insufficient study of the role of antioxidant agents. Glutathione S-transferase (GST) isozymes contribute to the antioxidation reactions in the tissue via the glutathione pathway. The purpose in this study was to reveal the levels of the GST enzyme activity and protein expression of GSTP1 and GSTA1 isozymes in patients with tonsillitis and tonsil hypertrophy, and to investigate their role in the pathogenesis of these diseases. Sixteen patients with recurrent tonsillitis and 5 patients with ITH and were included in the study. Cytosolic extracts were prepared from post-tonsillectomy tissues of both patient groups and GST enzyme activities were measured. The expression of GSTP1 was found to be significantly higher than GSTA1 in tissue samples of patients with ITH and recurrent tonsillitis (P<0.001). Increased GST activity and GSTP1 isozyme expression were shown in patients with recurrent tonsillitis compared to the idiopathic tonsillar hypertrophy study group. There was a positive correlation between the expressions of GSTP1 (P=0.040; r=0.47). Increased GST activity and GSTP1 isozymes were demonstrated histologically in the pathogenesis of ITH and recurrent tonsillitis. We believe that the data of changes in antioxidant capacity, obtained from studies with more extensive and larger samples, would support our findings.

Phytoremediation: green technology for the removal of mixed contaminants of a water supply reservoir

The Iraí Reservoir, a water supply in Brazil, is constantly impacted by anthropogenic activities such as waste inputs from agriculture, hospitals and urbanization, resulting toxic cyanobacterial blooms causing economic, social and environmental problems. This study assessed the concentration of some common contaminants of the Iraí Reservoir, namely paracetamol, diclofenac and microcystin-LR and tested whether a laboratory scale Green Liver System® would serve as a suitable technology to remove these contaminants. Further, the study investigated whether the pollutants caused adverse effects to the macrophytes using catalase as a biomarker for oxidative stress and investigated whether biotransformation (glutathione S-transferase) was a main route for detoxification. Egeria densa, Ceratophyllum demersum and Myriophyllum aquaticum were exposed to a mixture of the three contaminants for 14 days in a concentration range similar to those detected in the reservoir. The plants removed 93% of diclofenac and 100% of MC-LR after 14 days. Paracetamol could not be detected. Catalase and glutathione S-transferase enzyme activities remained unaltered after the 14-day exposure, indicating that the mixture did not cause oxidative stress. The study showed that the aquatic macrophytes used are suitable tools to apply in a Green Liver System® for the remediation of mixed pollutants.

The activity of enzymes of glutathione metabolism in blood cells of patients with a high risk of manifestation of endogenous psychoses and patients with the first psychotic episode

To assess the activity of glutathione reductase (GR) and glutathione-S-transferase (GST) in blood cells of patients at clinical high-risk (HR) state for psychosis, in first-episode patients with schizophrenia and schizoaffective disorder (SD), and control group, and to seek correlations of these biochemical parameters with clinical assessments in patients. The study included male patients at HR (n=21, 16-25 years old), first-episode patients with schizophrenia (F20, n=14, 18-25 years old) and SD (F25, n=20, 16-25 years old), and 12 people of the control group (19-25 years old). Psychometric scales (SOPS, HDRS, and PANSS) and psychopathological methods were employed. GR and GST enzymatic activities were determined spectrophotometrically. The activities of platelet GR and GST in all groups of patients both before and after treatment were lower than in controls (p<0.01). The platelet GST activity was lower in patients at HR compared to patients with schizophrenia before treatment and lower than in patients with SD after treatment (p<0.05), it was higher in patients with schizophrenia than in patients with SD before treatment (p<0.05). Erythrocyte GST activity in patients with HR was lower than in patients with SD after treatment, and in the latter it exceeded that in patients with schizophrenia and controls (p<0.05). Complex and different patterns of changes in the activities of erythrocyte and platelet GR and GST in patients with schizophrenia spectrum disorders, occurring both before the first psychotic episode in the initial stage of disease, and in the first-episode patients, were detected. The activity of glutathione-converting enzymes in endogenous psychoses of the schizophrenic spectrum, including its early stages, can be used as a biomarker for predicting the development of psychosis, the course of disease, and as criteria for evaluation of therapeutic response to antipsychotic treatment.

Antioxidant Potential of Solanum nigrum Aqueous Leaves Extract in Modulating Restraint Stress-Induced Changes in Rat's Liver.

Introduction:This study was carried out to evaluate the antioxidant potential of crude extract of Solanum nigrum leaves and its active constituents as treatment against restraint stress in rat’s liver.Methods:For this purpose, male albino Wistar rats were treated with crude extract of leaves and its alkaloid and flavonoid fractions both before and after 6 h of acute restraint stress. Prooxidant status of rat liver was assessed by determining the levels of thiobarbituric acid reactive substances, reduced glutathione, alkaline phosphatase, alanine transaminase, aspartate aminotransferase, and the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST).Results:Six hours of restraint stress generated oxidative stress in rat’s liver resulted in a significant rise in the level of the aforementioned liver enzymes. On the other hand, SOD, CAT, and GST enzymatic activities showed a significant decline in their level. The administration of crude leaves extract, both before and after stress exposure, significantly prevented the rise in the level of liver enzymes and reverted the activities of studied biochemical parameters toward their normal control values. However, the reversion was found to be more prominent in after-stress group.Conclusion:The aforementioned results highlight the significant antioxidant potential of S. nigrum extracts. On the basis of our study, we suggest the possible use of S. nigrum leaves extract as a nutritional supplement for combating oxidative stress induced damage.

The Effect of Mercury Chloride and Boric Acid on Rat Erythrocyte Enzymes

The aim of this study was to investigate the effects of mercury chloride and boric acid on rat (Wistar albino) erythrocyte: glucose 6-phosphate dehydrogenase (G6PD), 6-phosphoglucona-te dehydrogenase (6PGD), thioredoxin reductase (TrxR), glutathione reductase (GR) and glutathione S-transferase (GST) enzymes in vivo, and the rat erythrocyte G6PD enzyme in vitro. In the in vivo study, 24 male rats were divated into three different groups: control (C), mercury chloride (M), and mercury chloride + boric acid (M + BA). At the completion of this study, a significant degree of inhibition for both G6PD and GST enzyme activity was observed in the M groups when compared to the C group (p < 0.05), and no significant effect was observed in the 6PGD enzyme. However, there was significantly increased TrxR and GR enzyme activity of both the M and M + BA groups (p < 0.05). In the in vitro study, the G6PD enzyme from rat erythrocytes was purified with 2',5'-ADP Sepharose-4B affinity chromatography, and the effect of both mercury chloride and boric acid on the enzyme activity was investigated. The results showed that boric acid increased the G6PD enzyme activity while the mercury ions that inhibited the enzyme activity (IC50 values of 346μM and Ki values of 387μM) were noncompetitive.

Acaricide resistance in Tetranychus urticae red form (Acari: Tetranychidae) collected from strawberry in southern Turkey: Bioassay and biochemical studies

Recent population outbreaks of Tetranychus urticae Koch (red form) (Acari: Tetranychidae) were observed in strawberry fields in southern Turkey. Growers frequently complained that acaricides becoming an inefficient means of controlling this polyphagous pest. Therefore, a laboratory based bioassay and biochemical tests were conducted to determine comparative acaricide resistance status of five fields and a lab population of T. urticae. Larval bioassays were conducted using etoxazole and spiromesifen, whereas adult bioassays were performed with abamectin and tebufenpyrad. Kinetic esterase and glutathione S-transferase (GST) enzyme activities were also determined using a microplate reader. When compared to the lab population, based on LC50 values, the resistance rations of field populations were found between 2.39–7.86, 6.80–15.39, 4.61–9.73, and 5.51–12.47-fold for abamectin, etoxazole, spiromesifen and tebufenpyrad, respectively. Total esterase and GST activities of field populations were much higher than of the lab population. A 7.72–10.69 mOD/min/mg protein and a 5.92–7.56 mOD/min/mg protein, esterase and GST enzyme activities were determined for field populations, respectively. Whereas these enzyme activities were found to be 3.83 and 5.49 mOD/min/mg protein for the susceptible lab population, respectively. The higher detoxification enzyme activities indicate that these two enzymes play an important role in metabolic pathway of acaricides in different T. urticae populations.

Ecotoxicological effects of fertilizers made from pulping waste liquor on earthworm Eisenia fetida

In recent years, increasing efforts have focused on production of organic-inorganic compound fertilizers using ammonium sulfite pulping waste liquor. However, their ecological effects on soil have not been studied. In this study, earthworm Eisenia fetida was exposed to various doses (0, 0.13, 0.26 and 0.52 kg/m2) for different time (7, 14, 21, and 28 d) to evaluate the effects of fertilizers made from pulping waste liquor, including reactive oxygen species (ROS) generation, antioxidant enzymes activities, glutathione S-transferase enzyme (GST) activity, malondialdehyde (MDA) content and DNA damage. Results showed that there were significant increase of ROS and MDA levels after 14 d, inducing production of antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)) as well as GST. Before 14 d, excess ROS and MDA caused damage to the DNA of earthworms, leading to gradual increase of Olive tail moment (OTM) in the comet assay. With the exposure time extended to 28 d, owing to the combined effects of elimination of free radicals by antioxidant enzymes and detoxification enzymes as well as self-repairing function of cells, ROS and MDA levels declined slightly and OTM gradually decreased. In summary, this study indicated that there was a toxicological effect on earthworms when fertilizers made from pulping waste liquor were applied to soil, which needs more attention.

Influence of sex on biomarkers of oxidative stress in the kidney, lungs, and liver of rabbits after exposure to diazinon

The present study evaluated the effect of two oral doses of the pesticide diazinon (25 and 125mg/kg bw) on four biochemical parameters (malondialdehyde and glutathione levels, and catalase and glutathione S-transferase enzymatic activities) in the kidney, lungs, and liver of rabbit after 10days of exposure. Malondialdehyde levels were significantly greater in exposed animals compared to controls, especially in the animals exposed to the higher dose of the pesticide. This result was reflected in the glutathione levels, which were significantly lower at that same higher dose. Catalase activity was also inhibited by the higher dose of the pesticide in all three organs analysed, whereas inhibition of glutathione S-transferase activity was only significant for the kidney and lungs. There were some slight differences between the sexes: taking the results for all three organs, the higher dose of diazinon resulted in a clearly significant inhibitory effect on the catalase activity and glutathione levels in males, and a significant enhancing effect on the malondialdehyde levels in females. These results help to confirm the interest of considering such endogenous factors in future ecotoxicological studies, and that the four biomarkers considered are suitable for reflecting the toxic effects of diazinon on rabbits, especially the effects related to oxidative stress. Graphical abstract.

Integration of multi-tissue PAH and PCB burdens with biomarker activity in three coastal shark species from the northwestern Gulf of Mexico

Tissue-based burdens of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were integrated with ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST) enzyme activity in bull (Carcharhinus leucas), blacktip (Carcharhinus limbatus), and bonnethead (Sphyrna tiburo) sharks from Galveston Bay, TX. The potential toxicity of these burdens was evaluated by calculation of toxic equivalents (TEQs). Concentrations of total PAHs (∑PAHs) were significantly greater in blacktip and bonnethead sharks than bull sharks in liver, but did not exhibit differences in muscle among species. Hepatic concentrations of ∑PAHs in these sharks (range of means: 1560–2200 ng/g wet wt.) were greater than concentrations previously reported in oysters from Galveston Bay (range of means: 134–333 ng/g dry wt.), which suggests that trophic dilution of PAHs may not be reflected in sharks. Total PCBs (∑PCBs) were significantly greatest in bull sharks and lowest in bonnetheads, while blacktips were intermediate to these species. EROD activity was greater in bonnetheads than the other species, whereas GST activity was significantly higher in blacktips and bonnetheads than in bull sharks. Integration of hepatic burdens with biomarker activity via constrained multivariate analysis found correlations for only a small number of individual PAH/PCB congeners. Hepatic TEQ measurements suggest potential physiological effects of these burdens compared to established TEQ thresholds for other taxa, although the likelihood of similar effects in sharks requires further study and the inclusion of toxic endpoints. Our findings indicate that sharks may be prone to the accumulation of PAHs and PCBs, which may result in negative health outcomes for these cartilaginous fishes.

Biochemical CuSO4 Toxicity in Drosophila melanogaster Depends on Sex and Developmental Stage of Exposure.

Copper is a transition metal that exists in different chemical forms (e.g., Cu2+,Cu+, and Cu0) and at high concentrations it is toxic. Here, we investigated the Cu2+-induced toxicity in Drosophila melanogaster, evaluating the survival, locomotion, and the activity of acetylcholinesterase (AChE) and glutathione S-transferase (GST) enzymes. Flies were exposed to Cu2+(0.1-1mmol CuSO4/kg of diet or approximately 0.1-1mM Cu2+) and allowed to mate during 24h. GST and AChE enzymes were evaluated in the larvae and in the head and the body (thorax + abdomen) of the adult male and females flies. The total number of adult females (0.4-1mM) and males (0.75 and 1mM) was decreased by CuSO4. The climbing ability was hampered in flies exposed to 1mM Cu2+. In larvae, Cu2+(0.4-1mM) increased AChE activity (P < 0.002). In males' heads, 0.4mM Cu2+ increased the AChE activity (P <0.01). In adults' bodies, Cu2+inhibited the activity in both sexes, but with greater effectiveness in males (0.1 to 1mM) than in females (1mM). Regarding GST activity, 0.1mM Cu2+increased, but 1mM decrease GST in larvae. In the head of flies, Cu2+decreased the GST activity at intermediate (0.4mM) and increased GST at the highest concentration (1mM) in males. In the bodies, the effect of Cu2+was similar. In conclusion, Cu2+exposure in D. melanogaster disrupted locomotion and enzymatic parameters that can be related to changes in AChE and in the detoxifying GST enzyme.