ABSTRACT
To increase our knowledge of the natural susceptibility of Triatoma infestans to an organophosphate insecticide, we performed toxicological and biochemical studies on three sylvatic populations from Bolivia and two populations from domestic dwellings from Bolivia and Argentina. Fifty-per-cent lethal doses (LD50) were determined based on the topical application of fenitrothion on first instar nymphs and mortality was assessed at 24 h. Both type of populations exhibited LD50ratios significantly higher than 1 with a range of the values (1.42-2.47); the maximum value were found in a sylvatic (-S) population, Veinte de Octubre-S. Samples were biochemically analysed using a glutathione S-transferase activity assay. The highest significant activity was obtained for Veinte de Octubre-S and the lowest activity was obtained for the reference population (102.69 and 54.23 pmol per minute per mg of protein respectively). Two out of the three sylvatic populations (Veinte de Octubre-S and Kirus Mayu-S) exhibited significantly higher glutathione S-transferase activity than that of the reference population. Based on this analysis of the natural susceptibility of this organism to organophosphate insecticides, continental and focal surveys of organophosphate susceptibility should be conducted to evaluate the evolution and distribution of this phenomenon.
Subject(s)
Animals , Fenitrothion , Glutathione Transferase/metabolism , Insecticides , Insecticide Resistance/physiology , Triatoma/drug effects , Bolivia , Housing , Nymph/drug effects , Trees , Triatoma/enzymologyABSTRACT
Microsomal glutathione transferase 1 (MGST1) is an integral homo-trimeric membrane protein with transferase and peroxidase activities. With glutathione as a co-substrate, it scavenges toxic compounds and may exert anti-apoptotic effect. We examined the effect of suppression of plasma membrane Ca2+-ATPase isoforms — PMCA2 or PMCA3 on MGST1 in PC12 cells. GSH level was significantly higher in PMCA2-reduced line, but similar GSSG/GSH ratios in all cell lines suggested an efficient protection or absence of oxidative stress. The ATP concentration decreased in both modified lines, although in PMCA2-suppressed cells the decrease was higher. Total GSTs activity in postmitochondrial fraction increased by 30% in the cells with reduced PMCA3. After treatment with MGST1 activator N-ethylmaleimide (NEM), the activity increased in both transfected lines by 30-40%. Real-time PCR also showed a higher mRNA expression of MGST1 in these lines. Staining with antibody recognizing all cytosolic and membrane-bound GSTs revealed the difference in oligomeric forms of GSTs, and specific anti-MGST1 antibody showed the presence of MGST1 hexamers in the transfected cells. Formation of similar hexamers was detected in the control line after treatment with peroxynitrite. Modification of MGST1 under reduced PMCAs amount may represent an adaptive mechanism that offers protection against the cytotoxicity mediated by increased Ca2+.
Subject(s)
Adaptation, Physiological/physiology , Animals , Enzyme Activation , Glutathione Transferase/metabolism , Microsomes/enzymology , PC12 Cells , Plasma Membrane Calcium-Transporting ATPases/metabolism , RatsABSTRACT
Objective To develop and optimize a module for the automatic production of N-succinimidyl-4-[18F] fluorobenzoate (18F-SFB) that is used for further 18F labelling C2A domain of Synaptotagmin Ⅰ . The conjugated compound was applied for detecting the tumor apoptosis in rabbit model after chemotherapy. Methods GE TRACERlab and TRACERlab FXF-N modules were modified and programmed to automatically produce 18 F-SFB which was further analyzed by high performance liquid chromatography (HPLC).C2A-glutathione S transferase (GST) was conjugated with 18F-SFB (18F-FB-C2A-GST) and subsequently purified by HPLC. Two rabbits grafted with VX2 lung cancer were first treated with chemotherapy and then,37 MBq of 18F-FB-C2A-GST was administered via the auricular vein. Serial PET/CT imagings were performed at 0.5, 1 and 2 h post-injection respectively. Tumor apoptosis was examined by pathological study. Results The TRACERlab FXFoG and TRACERlab FXF-N modules were successfully adapted to synthesize18F-SFB, with the radiochenmical yield (76.41 ±4.00)% (n = 10), the corrected yield (45.43 ±5.90 ) % and the radiochemical purity about 95%. The whole procedure for labeling 18 F-SFB was about 87 min.From PET/CT imagings, significant uptake was found in the tumor after chemotherapy, but no obvious up-take was found in heart, lungs and liver. HE staining demonstrated large number of apoptotic bodies within the tumor tissues. Conclusions 18 F-SFB can be automatically synthesized. 18F-FB-C2A-GST might be useful for the detection of apoptosis in tumor after chemotherapy.
ABSTRACT
Glutathione S-transferases(GSTs) are a family of soluble detoxification enzymes which use reduced glutathione(GSH) in conjugation and reduction reactions.Toxic electrophiles,including a variety of carcinogens,are substrates for the GSTs and are more easily excreted into bile or urine after conjugation or reduction .The three-dimensional structures of GSTs from several species,including humans,have been determined.GST activity has been found to present in all human tissues,and expression of the various GST isoenzymes differs in degree in the various tissues. Glutathione S-transferases may play a role in the protection of cells against toxic electrophiles and in the resistance to cancer chemotherapeutic agants.The polymorphisms of GSTs genes are one of the important factors that exercise influence on individual susceptibility to cancer.
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AIM: To investigate the relationship between the expressions of DNA topoisomerase (Topo), glutathione S-transferases (GSTs) and chemotherapy response, prognosis in acute leukemia (AL). METHODS: Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of TopoⅠ, Ⅱ?, Ⅱ? and GST?, ? from patients with AL. RESULTS: The results showed that the relative mRNA expression level of TopoⅡ?, TopoⅡ? and GST ? in AL group were significantly higher than that in normal subjects. GST?, however, was exactly reverse ( P
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AIM: To analyse the frequencies of individuals of the GSTP1 genotypes among the Han nationality in Guangdong province. METHODS: Polymerase chain reaction-restriction fragment length polymorphism was taken to analyse the GSTP1 genotypes and identify the gene frequencies. RESULTS: The proportion of AA(Ile/Ile),AG(Ile/Val) and GG(Val/Val) genotypes were 57 4%,35 9% and 6 7%, respectively. CONCLUSION: The frequencies of individuals carrying homozygous of the GSTP1 variant allele were 6.7% among the Han nationality in Guangdong province.
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AIM: To detect the effect of Sini decoction on glutathione S-transferase (GST) mRNA expression in the ischemic myocardium. METHODS: Kunming mice were randomly divided into control group, ischemic group and Sini decoction group. Total RNA was extracted from the myocardium of mice in each group. The effect of Sini decoction on the expression of GST gene was detected by RT-PCR. RESULTS: The expression of GST mRNA in Sini decoction group was significantly up-regulated compared with the ischemic group and control group. CONCLUSION: Sini decoction can promote the expression of GST gene, which may be related to its protective effect on ischemic myocardium.
ABSTRACT
The clnical significance of serum glutathione S-transferase (GST) activity determination was evaluated by parallel measurements of GST and GPT activity inthe seraof 192 patients with liver diseases and 721 patients without liver diseas es. TheGST activity was significantly increased in the former, but it hadn't anychanges in patients without liver diseases. The highest GST activity was found in patients with severe hepatitis. In contrast to survival, the GST activity was persistently increased in those patients died later,and there appeared a "GST/GPT dissociation phenomenon". Although GPT activity had been normal in the convalescent stage of patients with hepatitis, the GST level in most of them was still high and different degree of pathological changes were also present in liver biopsy. Our data suggested that GST activity measurements might be a more sensitive parameter of liver cell damage than usual GPT measurements, and it might be valuable in evaluation of prognosis of severe hepatitis, and differentiation of hepa-tocellular jaundice from obstructive and hemolytic jaundice.