The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Amanda Callaghan - One of the best experts on this subject based on the ideXlab platform.
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relationship between biomarker activity and developmental endpoints in chironomus riparius meigen exposed to an Organophosphate Insecticide
Ecotoxicology and Environmental Safety, 2002Co-Authors: Mark Crane, Wanwisu Sildanchandra, R Kheir, Amanda CallaghanAbstract:The biomarkers acetylcholinesterase (AChE) and glutathione S-transferase (GST) were measured in fourth-instar Chironomus riparius Meigen larvae exposed to the Organophosphate Insecticide pirimiphos methyl (0, 5, 10, and 50 ng/g) for 48 or 96 h, and at high or low food ration. Larvae exposed to 50 ng/g pirimiphos methyl died within 48 h. The weight of larvae exposed to 10 ng/g pirimiphos methyl was significantly lower than those exposed to 0 and 5 ng/g. AChE activity was significantly reduced in larvae exposed to 10 ng/g, but GST activity remained unaffected. Lower food ration reduced larval weights across all treatments but did not affect biomarker measurements. Insecticide exposure was associated with a longer time to adult emergence and oviposition, fewer egg masses, a greater proportion of deformed egg masses, and fewer eggs.
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a comparison of the effects of Organophosphate Insecticide exposure and temperature stress on fluctuating asymmetry and life history traits in culex quinquefasciatus
Chemosphere, 2001Co-Authors: Mandla Mpho, Graham J Holloway, Amanda CallaghanAbstract:Effects of exposure to a non-chemical (temperature) or chemical (Organophosphate Insecticide) stressor during larval development were compared in Culex quinquefasciatus mosquitoes. Stress was measured in two ways: using conventional life history traits (survival, development time and a measure of body size) and by calculating the degree of developmental instability from the departure from bilateral symmetry of wing characters (fluctuating asymmetry). Increasing Insecticide dose, but not temperature, was observed to elevate wing fluctuating asymmetry in male but not female mosquitoes. Insecticide treatment reduced survival and was associated with a significant reduction in wing trait sizes in both females and males but did not significantly affect development time. Temperature was associated with a significant reduction in all life history traits in both sexes. Therefore wing fluctuating asymmetry in C. quinquefasciatus cannot be used as a general biomonitor of all stress, although it may have potential as a more specific monitor of chemical stress. It needs to be complimented with other measures such as life history and biochemical methods. The significant differences in response between sexes may impact on results of short-term larval exposures to Insecticides.
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an optimized microtiterplate assay to detect acetylcholinesterase activity in individual chironomus riparius meigen
Environmental Toxicology and Chemistry, 2000Co-Authors: Thomas C Fisher, Mark Crane, Amanda CallaghanAbstract:A sensitive microtiter plate assay to detect acetylcholinesterase activity in fourth-instar Chironomus riparius (Meigen) larvae was developed and optimized to allow the measurement of pesticide inhibition in individuals. Optimal conditions, including enzyme concentration, pH, and substrate concentration, allow the sensitive measurement of changes in activity following exposure to the Organophosphate Insecticide chlorpyrifos. Significant reductions in activity were observed at pesticide doses of 0.05, 0.1, 1.0, and 5 mg/L following a 48-h exposure.
Gisela Kristoff - One of the best experts on this subject based on the ideXlab platform.
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different effects of subchronic exposure to low concentrations of the Organophosphate Insecticide chlorpyrifos in a freshwater gastropod
Ecotoxicology and Environmental Safety, 2013Co-Authors: Pamela R Rivadeneira, Gisela Kristoff, Macarena Agrelo, Sofia OteroAbstract:Abstract Chlorpyrifos is an Organophosphate Insecticide used for pest control on a number of food crops in many parts of the world. In recent years, there has been an important decrease in the number of organisms of Planorbarius corneus. Since the presence of pesticides in the water can be one of the reasons for this decrease, it is very important to study the effect of subchronic exposure to environmental concentrations of pesticides on these organisms. The aim of the present work was to investigate different effects of the subchronic exposure to low concentrations of the Organophosphate chlorpyrifos in P. corneus and the possibility to use these as biomarkers. To this end, we have exposed the organisms to 0.4 and 5 μg L−1 of chlorpyrifos for 14 days and recorded the number of egg masses, the number of eggs per mass, the number of eggs without embryo, the time for hatching, and the % of hatching and survival. We have also determined the activities of cholinesterases, carboxylesterases and glutathione S-transferase in whole organism soft tissue and in the gonads. A 14 days exposure to 0.4 μg L−1 caused an increase in the number of egg masses without eggs and a decrease in carboxylesterases measured with p-nitrophenyl butyrate. However the exposure to 5 μg L−1 also caused an increase in the time for hatching, a decrease in the % of hatching and survival and also inhibition of cholinesterases and carboxylesterases with p-nitrophenyl acetate and butyrate. In contrast, the glutathione S-transferase has not been modified with the tested concentrations. We concluded that when P. corneus exposed to chlorpyrifos for 14 days, the CES determined with p-nitrophenyl butyrate proved to be the most sensitive biomarker. However, exposure to environmental concentrations showed a decrease in the reproduction ability which could cause a decrease in the number of organisms of this species.
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Effects of the Organophosphate Insecticide azinphos-methyl on the reproduction and cholinesterase activity of Biomphalaria glabrata
Chemosphere, 2011Co-Authors: Gisela Kristoff, Luis Claudio Cacciatore, Noemí R. Verrengia Guerrero, Adriana C. CochónAbstract:Abstract Azinphos-methyl is an Organophosphate Insecticide used for pest control on a number of food crops in many parts of the world. The snail Biomphalaria glabrata is a freshwater gastropod widely distributed in South America, Central America and Africa. The aim of the present work was to investigate whether azinphos-methyl causes alterations in the reproduction of B. glabrata . To this end, gastropod pigmented specimens were exposed to various concentrations of the Insecticide (0.021, 0.5, 2.5, and 5 mg L −1 ) for either 2 or 14 d. Along 14 d, several reproduction parameters and cholinesterase (ChE) activity were evaluated. In each group, the number of egg masses, the number of eggs per mass, the number of hatchings, the time to hatching, and the survival of the offspring after one month of treatment was evaluated. The results showed that, depending on the concentration and time of exposure, azinphos-methyl induced alterations in the reproduction of B. glabrata . These alterations were mainly represented by a decrease in the number of egg masses, and, in some cases, by a lower number or even the total absence of hatchings. Thus, the gastropods exposed to 2.5 and 5 mg L −1 of azinphos-methyl for 14 d showed ChE inhibitions higher than 35% along time and completely lost their ability to reproduce. On the other hand, exposure to high acute concentrations or exposure to low concentrations for 14 d resulted in ChE inhibition equal to or lower than 35% between 7 and 14 d of treatment and similar alterations in reproduction. These were represented by a decrease in the number of egg masses. At low pestice levels, the number of egg masses and the number of offspring resulted to be more sensitive biomarkers than ChE inhibition. It is concluded that the Insecticide azinphos-methyl can cause a decline in the reproductive performance of B. glabrata .
Thomas C Fisher - One of the best experts on this subject based on the ideXlab platform.
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an optimized microtiterplate assay to detect acetylcholinesterase activity in individual chironomus riparius meigen
Environmental Toxicology and Chemistry, 2000Co-Authors: Thomas C Fisher, Mark Crane, Amanda CallaghanAbstract:A sensitive microtiter plate assay to detect acetylcholinesterase activity in fourth-instar Chironomus riparius (Meigen) larvae was developed and optimized to allow the measurement of pesticide inhibition in individuals. Optimal conditions, including enzyme concentration, pH, and substrate concentration, allow the sensitive measurement of changes in activity following exposure to the Organophosphate Insecticide chlorpyrifos. Significant reductions in activity were observed at pesticide doses of 0.05, 0.1, 1.0, and 5 mg/L following a 48-h exposure.
Mark Crane - One of the best experts on this subject based on the ideXlab platform.
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relationship between biomarker activity and developmental endpoints in chironomus riparius meigen exposed to an Organophosphate Insecticide
Ecotoxicology and Environmental Safety, 2002Co-Authors: Mark Crane, Wanwisu Sildanchandra, R Kheir, Amanda CallaghanAbstract:The biomarkers acetylcholinesterase (AChE) and glutathione S-transferase (GST) were measured in fourth-instar Chironomus riparius Meigen larvae exposed to the Organophosphate Insecticide pirimiphos methyl (0, 5, 10, and 50 ng/g) for 48 or 96 h, and at high or low food ration. Larvae exposed to 50 ng/g pirimiphos methyl died within 48 h. The weight of larvae exposed to 10 ng/g pirimiphos methyl was significantly lower than those exposed to 0 and 5 ng/g. AChE activity was significantly reduced in larvae exposed to 10 ng/g, but GST activity remained unaffected. Lower food ration reduced larval weights across all treatments but did not affect biomarker measurements. Insecticide exposure was associated with a longer time to adult emergence and oviposition, fewer egg masses, a greater proportion of deformed egg masses, and fewer eggs.
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an optimized microtiterplate assay to detect acetylcholinesterase activity in individual chironomus riparius meigen
Environmental Toxicology and Chemistry, 2000Co-Authors: Thomas C Fisher, Mark Crane, Amanda CallaghanAbstract:A sensitive microtiter plate assay to detect acetylcholinesterase activity in fourth-instar Chironomus riparius (Meigen) larvae was developed and optimized to allow the measurement of pesticide inhibition in individuals. Optimal conditions, including enzyme concentration, pH, and substrate concentration, allow the sensitive measurement of changes in activity following exposure to the Organophosphate Insecticide chlorpyrifos. Significant reductions in activity were observed at pesticide doses of 0.05, 0.1, 1.0, and 5 mg/L following a 48-h exposure.
Muhammad Helmi - One of the best experts on this subject based on the ideXlab platform.
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Geospatial model of Organophosphate Insecticide residues in shallot land in Wanasari Sub-district, Brebes Regency, Central Java Province, Indonesia
E3S Web of Conferences, 2020Co-Authors: Indratin, Mochamad Arief Budihardjo, Muhammad HelmiAbstract:Organophosphates are a group of chemicals that are still allowed to be used in Indonesia and much preferred by most farmers. Excessive usage of Organophosphate is expected to contaminate the soil, water, plants, the environment and humans. This research was aimed to create the geospatial models of Organophosphate Insecticide residues which consist of Chlorpyrifos, Diazinon and Profenofos on farms of shallots production centers. The research was performed in the field of shallots production agriculture in Wanasari sub-district, Brebes Regency in March-June 2020. The extraction of multiresidue pesticides method used was the QuECheRS and the measurement of residues used the 2014 GC Shimadzu with Electron Capture Detector (ECD) which was carried out in the IAERI Laboratory. Meanwhile, the geospatial modeling of Organophosphate Insecticide residues was done by using the Spline Interpolation method in ArcGIS 10.4, which was carried out in Diponegoro University's CoREM laboratory. The analysis of soil samples taken from 44 sampling points showed that the Organophosphate Insecticide Chlorpyrifos was at the level of
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Geospatial model of Organophosphate Insecticide residues in shallot land in Wanasari Sub-district, Brebes Regency, Central Java Province, Indonesia
E3S Web of Conferences, 2020Co-Authors: Indratin, Mochamad Arief Budihardjo, Muhammad HelmiAbstract:Organophosphates are a group of chemicals that are still allowed to be used in Indonesia and much preferred by most farmers. Excessive usage of Organophosphate is expected to contaminate the soil, water, plants, the environment and humans. This research was aimed to create the geospatial models of Organophosphate Insecticide residues which consist of Chlorpyrifos, Diazinon and Profenofos on farms of shallots production centers. The research was performed in the field of shallots production agriculture in Wanasari sub-district, Brebes Regency in March-June 2020. The extraction of multiresidue pesticides method used was the QuECheRS and the measurement of residues used the 2014 GC Shimadzu with Electron Capture Detector (ECD) which was carried out in the IAERI Laboratory. Meanwhile, the geospatial modeling of Organophosphate Insecticide residues was done by using the Spline Interpolation method in ArcGIS 10.4, which was carried out in Diponegoro University's CoREM laboratory. The analysis of soil samples taken from 44 sampling points showed that the Organophosphate Insecticide Chlorpyrifos was at the level of <LoD-0.0949 mg/kg, Diazinon found at the level of <LoD-28.1732 mg/kg, and Profenofos was at the level of <LoD-0,0919 mg/kg.