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J.a. Tsitsipis - One of the best experts on this subject based on the ideXlab platform.
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Organophosphate resistance in olive fruit fly, Bactrocera oleae, populations in Greece and Cyprus.
Pest management science, 2006Co-Authors: Panagiotis J. Skouras, Kostas D. Mathiopoulos, John T. Margaritopoulos, Nicos Seraphides, Ioannis M. Ioannides, Evi G Kakani, J.a. TsitsipisAbstract:The olive fruit fly Bactrocera oleae (Gmelin) (Diptera: Tephritidae) is the most important pest of olives in countries around the Mediterranean basin. Its control has been based mostly on bait sprays with organophosphate insecticides (usually Dimethoate or fenthion) for about 40 years. In the present study, the resistance status of olive fruit fly populations to Dimethoate was examined in Greece and Cyprus over 2 years. Thirty-one populations from various regions of Greece, nine from Cyprus and one laboratory susceptible strain, which served as a control, were assayed by topical application of Dimethoate. Considerable variation in the resistance levels to Dimethoate was recorded in the populations of B. oleae, with resistance ratios ranging from 6.3 to 64.4 (ED50 values 12.5–128.7 ng Dimethoate per insect). The highest resistance ratios were found in populations from Crete, and the lowest in those from Cyprus. This variation could be attributed to different selection pressures from insecticidal applications among populations from the various regions. Migration of resistant genotypes, either autonomous or via commerce, may also be involved. Copyright © 2006 Society of Chemical Industry
Janet Hemingway - One of the best experts on this subject based on the ideXlab platform.
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Altered Acetylcholinesterase Confers Organophosphate Resistance in the Olive Fruit Fly Bactrocera oleae
Pesticide Biochemistry and Physiology, 2001Co-Authors: John Vontas, Nikos Cosmidis, Michael Loukas, Spyridon C. Tsakas, Mir Jalil Hejazi, Anna Ayoutanti, Janet HemingwayAbstract:Abstract An organophosphate-resistant strain of the olive fruit fly Bactrocera oleae , the most important pest for olive orchards worldwide, was obtained by laboratory selection with Dimethoate. Resistance mechanisms were investigated in comparison with the colonized parental strain and a field population collected from the same area after 12 years of continuous Dimethoate-based insecticide pressure. Combined biochemical and bioassay data suggested that, although esterase and/or glutathione S -transferase metabolic pathways were present and active against Dimethoate, they were not selected for and did not have a major role in resistance. There was no evidence of increased oxidase activity in the resistant strains or significant synergism of Dimethoate toxicity by piperonyl butoxide; thus, oxidative metabolism was not a major component of resistance. An altered acetylcholinesterase (AChE) with poorer catalytic efficiency for the substrate acetylthiocholine iodide and 5- to 16-fold lower sensitivity to inhibition by omethoate was the major resistance mechanism. Dimethoate selected the insensitive AChE allele(s) in the resistant insects, which were also insensitive to paraoxon, but the altered AChE mechanism conferred negative cross-resistance to the carbamate propoxur.
Lotfi Achour - One of the best experts on this subject based on the ideXlab platform.
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antioxidant rich date palm fruit extract inhibits oxidative stress and nephrotoxicity induced by Dimethoate in rat
Journal of Physiology and Biochemistry, 2012Co-Authors: Emna Behija Saafiben Salah, Amira El Arem, Mouna Louedi, Mongi Saoudi, Abdelfattah Elfeki, Abdelfattah Zakhama, Mohamed Fadhel Najjar, Mohamed Hammami, Lotfi AchourAbstract:Recent investigations have proved the crucial role of nutritional antioxidants to prevent the damage caused by toxic compounds. In this study, the antioxidant effect of date palm fruit extract on Dimethoate-induced oxidative stress and nephrotoxicity in rat is investigated and compared with the effect of the well-known antioxidant vitamin C. Male Wistar rats were randomly divided into six groups of ten each: a control group (C), a group that received Dimethoate (20 mg/kg body weight) (D), a group given Deglet Nour extract (DNE), a group treated with DNE 30 min before the administration of Dimethoate (DNE + D), a group which received VitC (100 mg/kg body weight) plus Dimethoate (Vit C + D), and a group given Dimethoate for the first month and DNE 30 min after administration of Dimethoate, during the second month (D + DNE). These components were daily administered by gavage for 2 months. After completing the treatment period, blood samples from rats were collected under inhaled diethyl ether anesthesia for serum urea, uric acid, and creatinine levels, while the rat kidneys were obtained for enzyme assays and histology. Oral administration of Dimethoate in rats induced a marked renal failure characterized by a significant increase in serum creatinine and urea levels (p < 0.01) in addition to a significant decrease in serum uric acid (p < 0.05). Interestingly, these drastic modifications were accompanied by a marked enhancement of lipid peroxidation in kidney, indicating a significant induction of oxidative damage (p < 0.01) and dysfunctions of enzymatic antioxidant defenses. These biochemical alterations were also accompanied by histological changes in kidney revealed by a narrowed Bowman’s space, tubular degeneration, tubular cell desquamation, and tubular dilatation of proximal tubules. Treatment with date palm fruit extract (Deglet Nour) and also with vitamin C significantly (p < 0.05) reversed the serum renal markers to their near-normal levels when compared with Dimethoate-treated rats. In addition, Deglet Nour extract and vitamin C significantly reduced lipid peroxidation, restored the antioxidant defense enzymes in the kidney, and improved the histopathology changes. The present findings indicate that in vivo date palm fruit may be useful for the prevention of oxidative stress-induced nephrotoxicity.
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protective effect of date palm fruit extract phoenix dactylifera l on Dimethoate induced oxidative stress in rat liver
Experimental and Toxicologic Pathology, 2011Co-Authors: Emna Behija Saafi, Mouna Louedi, Abdelfattah Elfeki, Abdelfattah Zakhama, Mohamed Fadhel Najjar, Mohamed Hammami, Lotfi AchourAbstract:Abstract Nowadays, people’s exposure to chemical compounds such as organophosphorus insecticides is continuously on the rise more and more. Theses compounds have induced an excessive production of free radicals which are responsible for several cell alterations in the organism. Recent investigations have proved the crucial role of nutritional antioxidants to prevent the damage caused by toxic compounds. In this study, we investigate the role of date palm fruit extract (Phoenix dactylifera L.) in protection against oxidative damage and hepatotoxicity induced by subchronic exposure to Dimethoate (20 mg/kg/day). Oral administration of Dimethoate caused hepatotoxicity as monitored by the increase in the levels of hepatic markers enzymes (transaminases, alkaline phosphatase, gamma-glutamyl transferase and lactate dehydrogenase), as well as in hepatic malondialdehyde thus causing drastic alteration in antioxidant defence system. Particularly, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were found increased by Dimethoate while catalase (CAT) activity was reduced significantly. These biochemical alterations were accompanied by histological changes marked by appearance of vacuolization, necrosis, congestion, inflammation, and enlargement of sinusoids in liver section. Pretreatment with date palm fruit extract restored the liver damage induced by Dimethoate, as revealed by inhibition of hepatic lipid peroxidation, amelioration of SOD, GPx and CAT activities and improvement of histopathology changes. The present findings indicate that in vivo date palm fruit may be useful for the prevention of oxidative stress induced hepatotoxicity.
Panagiotis J. Skouras - One of the best experts on this subject based on the ideXlab platform.
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Organophosphate resistance in olive fruit fly, Bactrocera oleae, populations in Greece and Cyprus.
Pest management science, 2006Co-Authors: Panagiotis J. Skouras, Kostas D. Mathiopoulos, John T. Margaritopoulos, Nicos Seraphides, Ioannis M. Ioannides, Evi G Kakani, J.a. TsitsipisAbstract:The olive fruit fly Bactrocera oleae (Gmelin) (Diptera: Tephritidae) is the most important pest of olives in countries around the Mediterranean basin. Its control has been based mostly on bait sprays with organophosphate insecticides (usually Dimethoate or fenthion) for about 40 years. In the present study, the resistance status of olive fruit fly populations to Dimethoate was examined in Greece and Cyprus over 2 years. Thirty-one populations from various regions of Greece, nine from Cyprus and one laboratory susceptible strain, which served as a control, were assayed by topical application of Dimethoate. Considerable variation in the resistance levels to Dimethoate was recorded in the populations of B. oleae, with resistance ratios ranging from 6.3 to 64.4 (ED50 values 12.5–128.7 ng Dimethoate per insect). The highest resistance ratios were found in populations from Crete, and the lowest in those from Cyprus. This variation could be attributed to different selection pressures from insecticidal applications among populations from the various regions. Migration of resistant genotypes, either autonomous or via commerce, may also be involved. Copyright © 2006 Society of Chemical Industry
V K Das - One of the best experts on this subject based on the ideXlab platform.
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acute toxicity and behavioral responses of common carp cyprinus carpio linn to an organophosphate Dimethoate
World Journal of Zoology, 2009Co-Authors: R N Singh, N N Singh, R K Pandey, V K DasAbstract:2 Abstract: Dimethoate, a broad spectrum OP insecticide is a potential toxic pollutant, adversely affecting the fauna of aquatic ecosystem. The aim of present study was to assess the acute toxicity of Dimethoate on fingerlings of common carp, Cyprinus carpio. The fingerlings were exposed to Dimethoate to determine LC values for 24, 48, 72 and 96 h and to study the behavioural alterations. The mortality data obtained was 50 analyzed by LC software program of U.S. EPA based on Finney's Probit Analysis statistical method and was 50 found to be 1.84, 1.78, 1.68 and 1.61 mg/L respectively. The test fish exhibited erratic swimming, increased surfacing, decreased rate of opercular movement, copious mucous secretion, reduced agility and inability to maintain normal posture and balance with increasing exposure time. Dissolved oxygen content of the troughs was measured at 24, 48, 72 and 96 h to assess the impact of toxicant exposure on oxygen consumption. Oxygen consumption of exposed fishes showed significant decline at all concentrations. It is concluded that Dimethoate is highly toxic to fingerlings of common carp and severely affects their physiology and behaviour.