Purification of glutathione S-transferase from Van Lake fish (Chalcalburnus tarichii Pallas) muscle and investigation of some metal ions effect on enzyme activity

Investigation of Potential Effects of Some Indole Compounds on the Glutathione S-Transferase Enzyme

Glutathione S-transferases (GSTs) belong to the superfamily of multifunctional detoxification isoenzymes with an important role in cellular signaling. They can prevent reactive electrophilic compounds from harming the body by covalently binding identical type of moleculs to each other. GSTs can be used alone or in combination for cancer detection or diagnosis, in addition to therapeutic interventions. In recent years, indoles have become important due to their structural properties and biological activities such as antitubercular, antiulcer, anti-oxidant, and antidiabetic, as well as for the development of new anticancer agents. The current research investigated effects of some indoles with 3-carboxaldehyde structure on the GST enzyme activity. Impacts of various concentrations of indoles on the in vitro GST activity were examined. While IC50 values for the compounds ranged from 0.042 to 1.570 mM, Ki values changed between 0.018 ± 0.01 and 1.110 ± 0.15 mM. 6-Methylindole-3-carboxaldehyde (1b) exhibited the highest inhibitory effect among the indoles examined. Indole derivatives used in the study can be evaluated in further pharmacological studies due to their effects on GST activity.

Partial Purification of Glutathione S-transferase Enzyme From the Seed of Mallow (Malva Slyvestris L.) and Investigation of the Inhibition Kinetics of Some Heavy Metals

Glutathione S-Transferase (GST) enzyme is abundant in mammals, insects, fish and microorganisms, as well as in various tissues of these species, particularly in tissues exposed to xenobiotics from the environment. As a result, the enzyme execute detoxifying function by scavenging a diverse range of xenobiotics, such as chemotherapeutic medicines, environmental carcinogens and endogenous compounds. In this study, GST enzyme was partially purified from mallow (Malva slyvestris L.) seed for the first time and the kinetic parameters were determined. The optimum ionic intensity was found in 400 mM Tris-Buffer, optimum pH: 7.0, and optimum substrate concentration was determined as 0.2 mM. One of the biggest reasons for deterioration of ecological balance in nature is heavy metal accumulation in soil, air and water which becomes a major threat to the vital activities of living things. In this study, inhibitory effects of Cd^+ 2, Ag⁺, Zn^+ 2 and Fe^+ 3 heavy metals, which are common in nature, on mallow seed glutathione S-transferase enzyme were investigated. Each heavy metal showed micromolar inhibitory effects on enzyme activity. IC₅₀ values of the metals were calculated as 60.93, 74.602, 178.22 and 369 µM, respectively.

Effects of different drugs and hormone treatment on Toxoplasma gondii glutathione S-transferase 2

BACKGROUND

Glutathione S-transferase (GST) in eukaryotic organisms has multiple functions such as detoxifying endogenous/exogenous harmful substances to protect cells from oxidative damage, participating in sterol synthesis and metabolism, and regulating signaling pathways. Our previous work identified an important GST protein in Toxoplasma that contributes to vesicle trafficking called TgGST2, the deletion of which significantly reduces the virulence of the parasite. Meanwhile, we considered that TgGST2 may also play a role in other pathways of parasite life activities.

METHODS

The tertiary structures of TgGST2 as well as estradiol (E2) and progesterone (P4) were predicted by trRosetta and Autodock Vina software, the binding sites were analyzed by PyMol's GetBox Plugin, and the binding capacity was evaluated using Discovery Studio plots software. We examined the influence of E2 and P4 on TgGST2 via glutathione S-transferase enzyme activity and indirect immunofluorescence assay (IFA) and through the localization observation of TgGST2 to evaluate its response ability in different drugs.

RESULTS

TgGST2 could bind to exogenous E2 and P4, and that enzymatic activity was inhibited by the hormones in a concentration-dependent manner. Upon P4 treatment, the localization of TgGST2 changed from Golgi and vesicles to hollow circles, leading to abnormal localization of the molecular transporter Sortilin (VPS10) and microneme proteins (M2AP and MIC2), which ultimately affect the parasite life activities, but E2 had no significant effect. Moreover, diverse types of drugs had divergent effects on TgGST2, among which treatment with antifungal agents (voriconazole and clarithromycin), anticarcinogens (KU-60019, WYE-132 and SH5-07) and coccidiostats (dinitolmide and diclazuril) made the localization of TgGST2 appear in different forms, including dots, circles and rod shaped.

CONCLUSIONS

Our study shows that TgGST2 plays a role in sterol treatment and can be affected by P4, which leads to deficient parasite motility. TgGST2 exerts divergent effects in response to the different properties of the drugs themselves. Its responsiveness to diverse drugs implies a viable target for the development of drugs directed against Toxoplasma and related pathogenic parasites.

Ackee (Blighia sapida K.D. Koenig) Leaves and Arils Methanolic Extracts Ameliorate CdCl2-Induced Oxidative Stress Biomarkers in Drosophila melanogaster

Different ethnomedical benefits have been documented on different parts of Ackee (Blighia sapida); however, their roles in ameliorating oxidative damages are not well established. CdCl2 inhibitory effects on some oxidative-stress biomarkers and ameliorative potentials of Ackee leaves (AL) and arils (AS) methanolic extracts were studied using Drosophila melanogaster as a model. One to 3-day-old D. melanogaster flies were orally exposed to different concentrations of CdCl2 in their diet for 7 days. The fly’s survival profile and negative geotaxis assays were subsequently analysed. Methanolic extracts of AL and AS treatments showed negative geotaxis behaviour, and extracts were able to ameliorate the effect of Cd2+ on catalase and GST activities and increase total thiol and GSH levels, while it reduced the H2O2 generation ( $p\le 0.05$ ) when compared to the control. Furthermore, Cd2+ exhibited noncompetitive and uncompetitive enzyme inhibition on catalase and GST activities, respectively, which may have resulted in the formation of Enzyme-substrate-Cd2+ transition complexes, thus inhibiting the conversion of substrate to product. This study, thus, suggests that the Cd2+ mechanism of toxicity was associated with oxidative damage, as evidenced by the alteration in the oxidative stress-antioxidant imbalance, and that the AL and AS extracts possess essential phytochemicals that could alleviate possibly deleterious oxidative damage effects of environmental pollutants such as CdCl2. Thus, Ackee plant parts possess essential phytonutrients which could serve as valuable resources in heavy metal toxicity management.

Toxoplasma gondii glutathione S-transferase 2 plays an important role in partial secretory protein transport

Toxoplasma gondii is an apicomplexan parasite, which has three unique secretory organelles: micronemes, rhoptries, and dense granules. Almost all the secreted proteins are transported through the endoplasmic reticulum (ER) and Golgi system to function in their respective destination by accurate targeting and packaging. Glutathione S-transferase (GST) is a supergene family enzyme that has multiple functions, which include regulation of cell proliferation and death signaling pathways, and participation in transportation and metabolism in mammal cells. However, the role of GST in Toxoplasma gondii has not been explained. In this study, we identified three GST proteins in T gondii, of which GST2 acts as a membrane protein that localizes to the Golgi-endosomal system and colocalizes with proteins involved in vesicle transport as well, including synaptobrevin, putative sortilin (VPS10), Rab5 and Rab6, which function as vesicle transport factors. Moreover, the loss of TgGST2 leads to Rab5 and Rab6 distribution of discrete puncta, and incorrect localization and decreased expression of several secretory proteins, and to significantly reduced invasion capacity and virulence to mice. Consistent with its relation to vesicle transport proteins, the distribution of TgGST2 relies on post-Golgi trafficking. Overall, our findings demonstrated that TgGST2 contributes to vesicle trafficking and plays a critical role in parasite lytic cycle.

How safe are the new green energy resources for marine wildlife? The case of lithium

Considering the increasing use of Lithium (Li) and the necessity to fulfil this demand, labile Li occurrence in the environment will be enhanced. Thus, additional research is needed regarding the presence of this element in marine environment and its potential toxic impacts towards inhabiting wildlife. The aim of the present study was to evaluate Li toxicity based on the exposure of Mytilus galloprovincialis to this metal, assessing the biochemical changes related with mussels' metabolism, oxidative stress and neurotoxicity. For this, organisms were exposed to different Li concentrations (100, 250, 750 μg/L) for 28 days. The results obtained clearly demonstrated that Li lead to mussels' metabolism depression. The present study also revealed that, especially at the highest concentrations, antioxidant and biotransformation enzymes were not activated, leading to the occurrence of lipid peroxidation and loss of redox homeostasis, with increased content in oxidized glutathione in comparison to the reduced form. Furthermore, after 28 days, higher Li exposure concentrations induced neurotoxic effects in mussels, with a decrease in acetylcholinesterase enzyme activity. The responses observed were closely related with Li concentrations in mussels' tissues, which were more pronounced at higher exposure concentrations. Such results highlight the potential toxic effects of Li to marine species, which may even be higher under predicted climate changes and/or in the presence of other pollutants.

Inhibitory effect of metals on animal and plant glutathione transferases

Glutathione transferases (GSTs) represent a widespread enzyme superfamily in eukaryotes and prokaryotes catalyzing different reactions with endogenous and xenobiotic substrates such as organic pollutants. The latter are often found together with metal contamination in the environment. Besides performing of essential functions, GSTs protect cells by conjugation of glutathione with various reactive electrophiles. The interference of toxic metals with this functionality of GSTs may have unpredictable toxicological consequences for the organisms. In this review results from the recent literature are summarized and discussed describing the ability of metals to inhibit intracellular detoxification processes in animals and plants.

In vivo biochemical evaluations of some β-lactam group antibiotics on glutathione reductase and glutathione S- transferase enzyme activities

OBJECTIVES

The aim of this study was to investigate whether some of the cephalosporin group antibiotics have inhibition effects on GR and GST enzymes with important functions in the metabolic pathway.

METHODS

In this study, some selected cephalosporin group antibiotics on GST and GR enzyme was carried out using 96 rats. 16 groups (16 × 6) were created from these rats, divided to another 4 groups (4 × 24). The resulting groups were named as sham groups, cefazolin groups, cefuroxime groups and cefoperazone groups, respectively. The antibiotics used were injected to cefazolin, cefuroxime and cefoperazone groups. The inhibition effects of the antibiotics were measured in the different time intervals (1st, 3th, 5th, 7th). The statistical investigation of the results was performed using the SPSS software program.

RESULTS

Results revealed the complex effects of the tested substances on GR and GST activity at different time intervals and in different tissues (p < 0.05). This indicated that the tested substances could be exposed to different interactions in vivo.

CONCLUSION

The tested antibiotics showed some significant inhibition effects on the GST and GR enzyme activity in some tissues of brain, eye and muscle. The interaction of enzyme - the drug is a key factor to highlight the toxicological mechanism. For this reason, the results obtained from in vivo experiments are crucial to explane the physiological properties of the enzymes.

The effects of some cephalosporins on acetylcholinesterase and glutathione S-transferase: an in vivo and in vitro study

BACKGROUND

Glutathione S-transferase (GST) and acetylcholinesterase (AChE) are important enzymes in the metabolism. GSTs are primarily available in phase II metabolism. AChE is vital for neurodegenerative disorders.

SUBJECTS AND METHODS

The in vitro and in vivo effects of cefoperazone sodium (CFP), cefuroxime (CXM), and cefazolin (CZO) were investigated on GST and AChE activity in the present study. GST was purified using Glutathione-Agarose affinity chromatography.

RESULTS

K_i constants of CFP, CXM, and CZO were 0.1392 ± 0.02, 1.5179 ± 0.33, and 1.006 ± 0.11 mM for GST and 0.3010 ± 0.07, 0.3561 ± 0.09, and 0.3844 ± 0.04 mM, for AChE, respectively. The most effective inhibitor was CFP for both enzymes in in vitro. CZO (50 mg/kg), CXM (25 mg/kg), and CFP (100 mg/kg) inhibit in vivo GST and AChE activities. CXM had the most effective in vivo inhibition on AChE and GST.

CONCLUSIONS

CZO, CXM, and CFP are effective AChE and GST inhibitors in both in vitro and in vivo.

Inhibitory Effects of Usnic and Carnosic Acid on Some Metabolic Enzymes: An In vitro Study

Background:

Natural products are produced via primary and secondary metabolism in different organisms. The compounds obtained via secondary metabolism are not essential for the survival of the organism, but they can have a different value for humans.

Objective:

The objective of this study was to examine inhibitory effects of Usnic Acid (UA), a well-known lichen secondary metabolite, and Carnosic Acid (CA), the primary antioxidant compound of Rosmarinus officinalis L., on purified Human Paraoxonase, (PON1), Glutathione Reductase (GR) and Glutathione S-Transferase (GST). These enzymes have antioxidant properties and a protective effect on the oxidation of free radicals. Hence, deficiencies of such enzymes inside cells can result in a buildup of toxic substances and cause some metabolic disorders.

Methods:

UA and CA were tested in various concentrations against human GST, PON1, and GR activity in vitro and they reduced human GST, PON1, and GR activity.

Results:

UA Ki constants were calculated as 0.012±0.0019, 0.107±0.06 and 0.21±0.1 mM for GST, PON1, and GR enzymes. CA Ki constants were determined as 0.028±0.009, 0.094±0.03 and 0.79±0.33 mM, for GST, PON1, and GR enzymes. UA and CA showed competitive inhibition for GR and GST enzymes, while they exhibited non-competitive inhibition for PON1.

Conclusion:

These findings indicate that UA and CA could be useful in drug development studies.

Influence of some β-lactam drugs on selected antioxidant enzyme and lipid peroxidation levels in different rat tissues

Antioxidant enzymes play an important role in body defense and free radical removal. Cephalosporins are β-lactam antibiotics. In this work, the effects of cefazolin, cefuroxime and cefoperazone which are cephalosporins on some selected antioxidant enzyme and levels of malondialdehyde (MDA) as lipid peroxidation product were investigated in kidney, liver, and brain tissues of albino female rats. Ninety-six albino rats were randomly divided into 16 groups of equal number (n = 6). 50 mg/kg cefazolin, 25 mg/kg cefuroxime, and 100 mg/kg cefoperazone were injected intraperitoneally to the groups (5th-8th and 9th-12th, and 13th-16th groups), respectively. The changes in glutathione reductase (GR), glutathione S-transferase (GST), superoxide dismutase (SOD), peroxidase (POD), and glutathione peroxidase (GSH-Px) levels were studied in each time point group and a time-dependent manner (at the 1st, 3rd, 5th and 7th hour). In addition, MDA levels were examined in all the tissues. The drugs evaluated in this study had different effects on the same enzyme in different tissues depending on time. MDA levels especially in cefazolin and cefoperazone experiments were lower in all the tissues; however, MDA levels were higher in brain and kidney tissues in the cefuroxime groups in a time-dependent manner (p < 0.05). These results revealed the complex effects of the tested drugs on different tissues at different time points. Therefore, the dose and use of these drugs should be adjusted correctly.

Overview of the toxic effects of titanium dioxide nanoparticles in blood, liver, muscles, and brain of a Neotropical detritivorous fish

The toxicity of titanium dioxide nanoparticles (TiO₂ -NP) in the blood, liver, muscle, and brain of a Neotropical detritivorous fish, Prochilodus lineatus, was tested. Juvenile fish were exposed to 0, 1, 5, 10, and 50 mg L^-1 of TiO₂ -NP for 48 hours (acute exposure) or 14 days (subchronic exposure) to evaluate changes in hematology, red blood cell (RBC) genotoxicity/mutagenicity, liver function (reactive oxygen species (ROS) production, antioxidant responses, detoxification, and histopathology), acetylcholinesterase (AChE) activity in muscles and brain, and Ti bioaccumulation. TiO₂ -NP did not cause genetic damage to RBC, but acutely decreased white blood cells (WBC) and increased monocytes. Subchronically, RBC decreased, mean cell volume and hemoglobin increased, and WBC and lymphocytes decreased. Therefore, NP has the potential to affect immune system and increase energy expenditure, reducing the fish's ability to avoid predator and to resist pathogens. In the liver, acute exposure decreased ROS and increased glutathione (GSH) content, while subchronic exposure decreased superoxide dismutase activity and increased glutathione-S-transferase (GST) activity and GSH content. GSH and GST seem to play an essential role in metabolizing NP and ROS, likely increasing hepatocytes' metabolic rate, which may be the cause of observed cell hypertrophy, disarrangement of hepatic cords and degenerative morphological alterations. Although most studies indicate that the kidney is responsible for metabolizing and/or eliminating TiO₂ -NP, this study shows that the liver also has a main role in these processes. Nevertheless, Ti still accumulated in the liver, muscle, and brain and decreased muscular AChE activity after acute exposure, showing neurotoxic potential. More studies are needed to better understand the biochemical pathways TiO₂ -NP are metabolized and how its bioaccumulation may affect fish homeostasis and survival in the environment.

Genome-wide identification of the entire 90 glutathione S-transferase (GST) subfamily genes in four rotifer Brachionus species and transcriptional modulation in response to endocrine disrupting chemicals

Genome-wide identification of glutathione S-transferase (GST), a major phase II detoxification enzyme, was investigated in four different aquatic model rotifer species Brachionus koreanus, B. plicatilis, B. rotundiformis, and B. calyciflorus. GSTs are ubiquitous antioxidant enzymes that play versatile function including cellular detoxification, stress alleviation, and production of the radical conjugates. Among the four rotifers, B. rotundiformis was found with the least number of GST genes (total 19 GST genes), whereas the other three species shared 23 to 24 GST genes. Among the identified GST genes, belonging to the cytosolic GST superfamily, the expansion of GST sigma classes mainly occurs through tandem duplication, resulting in tandem-arrayed gene clusters on the chromosomes. Overall, the number of genes discovered in this study was highest in the sigma class, zeta, alpha, and omega in descending order. With integration of phylogenetic analysis and xenobiotic-mediated GST mRNA expression patterns along with previous enzymatic activities, the functional divergence among species-specific GST genes was clearly observed. This study covers full identification of GST classes in three marine rotifer and one fresh-water rotifer species and their important role in marine environmental ecotoxicology.