ABSTRACT
The adverse effects of chlorpyrifos, cypermethrin, and imidacloprid on mitochondrial dysfunction and oxidative stress biomarkers were studied in rat liver. The liver deficiency was also confirmed by histological analysis and gel electrophoresis. Each insecticide was administered orally with five doses per week for 28 days to male albino rats at 1/50 of the LD50 per insecticide. The results demonstrated that the mitochondrial dysfunction was confirmed by a significant decrease in NADH dehydrogenase and ATPase activities. Oxidative stress biomarkers include malondialdehyde (MDA), and protein carbonyl content (PCC) were significantly increased. However, superoxide dismutase (SOD) and glutathione S-transferase (GST) as antioxidant enzymes were significantly decreased in the mitochondria of the rat liver. HPLC analysis showed a significant increase of the 8-hydroxy-2'-deoxyguanosine (8-OH-2DG) as a biomarker of the DNA damage in rat liver. In addition, the residue levels of 0.96 and 0.29 µg/mL serum were found for cypermethrin and imidacloprid, respectively. However, chlorpyrifos not detected using the HPLC analysis. Blue native polyacrylamide gel electrophoresis (BN-PAGE) analysis showed a change in the pattern and sequence of complexions of the electron transport chain in liver mitochondria with treatment by such insecticides. The hepatic histological examination also showed symptoms of abnormalities after exposure to these insecticides.
Subject(s)
Chlorpyrifos , Insecticides , Animals , Antioxidants/metabolism , Chlorpyrifos/metabolism , Chlorpyrifos/toxicity , Insecticides/metabolism , Insecticides/toxicity , Liver/metabolism , Mitochondria , Neonicotinoids , Nitro Compounds , Oxidative Stress , Protein Carbonylation , Pyrethrins , RatsABSTRACT
1,1-bis (p-chlorophenyl)-2, 2, 2-trichloroethane (DDT) has been used for control of malaria mosquitoes and other insect vectors of human diseases since 1945. Its use poses an environmental dilemma and efforts to replace it have been hampered by lack of information about its molecular target. This work identifies the 23 kDa band responsible for the DDT sensitivity in bees, as the OSCP and subunit "d" of the ATP synthase. The OSCP of the bee's ATP synthase contained 207 amino acids compared to 190 in bovine, which is insensitive to DDT, and the identities were only 47%. Subunit "d" of the bees had no counterpart in the bovine. Whether DDT is interacting only with OSCP, only with subunit "d", or with both subunits, remains to be assessed. Identification of the molecular target of DDT will lead the way to new target based insecticides aimed to protect plant, combat malaria and other insect transmitted diseases.
Subject(s)
Bees/enzymology , DDT/chemistry , Insect Proteins/chemistry , Insecticides/chemistry , Mitochondrial Proton-Translocating ATPases/chemistry , Animals , Bees/genetics , Cattle , Drug Resistance/drug effects , Drug Resistance/genetics , Humans , Insect Proteins/genetics , Insect Proteins/metabolism , Mitochondrial Proton-Translocating ATPases/genetics , Mitochondrial Proton-Translocating ATPases/metabolism , Protein Subunits , Species SpecificityABSTRACT
1,1-bis-(p-Chlorophenyl)-2,2,2-trichloroethane (DDT) inhibited the ATP hydrolytic activity of the ATP synthase from a DDT-susceptible insect (Apis mellifera) as well as a DDT-tolerant insect (Spodoptera littoralis), and from rat liver and bovine heart in a parallel way to its insecticidal properties and selectivity of action. Inhibition of the ATPase activity of these preparations by DDT was parallel to the poisoning of the source organism with DDT. Furthermore, both the inhibition and poisoning of insects were affected similarly by temperature. Inhibition of the insect enzyme activity by DDT was specific and differed from that by oligomycin or N,N-dicyclohexylcarbodi-imide (DCCD). PAGE analysis of the various preparations of the enzyme showed that the inhibition of the enzyme activity by DDT was associated with the presence of a selective protein band with an apparent molecular mass of 23 kDa. This protein band exists in the preparations from the DDT-susceptible insects but was absent from the preparations of the enzyme from the DDT-insensitive sources. Removal of this protein band from the enzyme rendered its activity insensitive to inhibition by DDT. The protein was purified directly from mitochondria and the DDT sensitivity was reconstituted upon its addition to the DDT-insensitive F1-ATPase. We conclude that this identified protein of the ATP synthase is the DDT target protein in insects.
