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Pest Management Science Apr 2013An evaluation was made of the effects of seven neurotoxic insecticides (esfenvalerate, indoxacarb, clothianidin, thiacloprid, azinphosmethyl, phosmet and imidacloprid),...
BACKGROUND
An evaluation was made of the effects of seven neurotoxic insecticides (esfenvalerate, indoxacarb, clothianidin, thiacloprid, azinphosmethyl, phosmet and imidacloprid), one insect growth regulator (novaluron) and two fungicides (myclobutanin and mancozeb), with water as the control, on the horizontal mobility of plum curculios exposed to dried pesticide residues. Mobility was recorded over a 2 h period using ethological tracking software. Mortality was recorded immediately after horizontal mobility experiments and 24 h later.
RESULTS
Esfenvalerate had the greatest impact on mobility. Immediately after exposure to this compound, plum curculios moved significantly greater distances and for a significantly longer period of time compared with all other compounds. After 24 h, esfenvalerate also led to high mortality rates (>86.0%). Exposure to azinphosmethyl and phosmet also led to high rates of mortality, although the impact on mobility was less pronounced. Exposure to indoxacarb, thiacloprid, imidacloprid, novaluron, myclobutanin and mancozeb had no impact on mobility and resulted in little to no mortality. Clothianidin affected mobility after a 2 h exposure period, and high mortality (60%) was recorded after 24 h.
CONCLUSIONS
The results indicate that, in the context of a treated orchard, plum curculios exposed to dried pesticide residues may be capable of foraging before succumbing to toxicant exposure, while exposure to pesticides such as esfenvalerate may rapidly incapacitate adult plum curculios.
Topics: Animals; Behavior, Animal; Female; Fungicides, Industrial; Insect Control; Insecticides; Male; Pesticide Residues; Weevils
PubMed: 23213003
DOI: 10.1002/ps.3445 -
Chemosphere Jun 2007Spraydrift and edge-of-field runoff are important routes of pesticide entry into streams. Pesticide contamination originating from spraydrift usually resides in the...
Spraydrift and edge-of-field runoff are important routes of pesticide entry into streams. Pesticide contamination originating from spraydrift usually resides in the water phase, while pesticides in contaminated runoff are to a large extent associated with suspended particles (SPs). The effects of two organophosphorous insecticides (OPs), chloropyrifos (CPF) and azinphos-methyl (AZP), on acetylcholinesterase (AChE) activity in rainbow trout were compared between two exposure scenarios, simulating spraydrift- and runoff-borne contamination events in the Lourens River (LR), Western Cape, South Africa. NOECs of brain AChE inhibition, determined after 1h of exposure followed by 24h of recovery, were 0.33microgl(-1) for aqueous CPF, 200mgkg(-1) for SP-associated CPF and 20mgkg(-1) for SP-associated AZP (at 0.5gl(-1) SP). The highest aqueous AZP concentration tested (3.3microgl(-1)) was without significant effects. Previously reported peak levels of aqueous CPF in the LR ( approximately 0.2microgl(-1)) are close to its NOEC (this study), suggesting a significant toxicological risk to fish in the LR. By contrast, reported levels of SP-associated OPs in the LR are 20-200-fold lower than their NOECs (this study). In a comparative in situ study, trout were exposed for seven days at agricultural (LR2, LR3) and upstream reference (LR1) sites. No runoff occurred during the study. Brain AChE was significantly inhibited at LR3. However, OP levels at LR3 (CPF 0.01microgl(-1); AZP 0.14microgl(-1)) were minor compared to concentrations having effects in the laboratory (see above). Additionally, muscle AChE activity was significantly higher in caged trout from LR1 than in animals maintained in laboratory tanks.
Topics: Acetylcholinesterase; Animals; Azinphosmethyl; Brain; Chlorpyrifos; Cholinesterase Inhibitors; Environmental Monitoring; Insecticides; Muscles; Oncorhynchus mykiss; Rivers; South Africa; Water Pollutants, Chemical
PubMed: 17418885
DOI: 10.1016/j.chemosphere.2007.02.056 -
Toxicology and Applied Pharmacology Sep 2001Ethylazinphos increases the passive proton permeability of lipid bilayers reconstituted with dipalmitoylphosphatidylcholine (DPPC) and mitochondrial lipids. A sharp...
Ethylazinphos increases the passive proton permeability of lipid bilayers reconstituted with dipalmitoylphosphatidylcholine (DPPC) and mitochondrial lipids. A sharp increase of proton permeability is detected at insecticide/lipid molar ratios identical to those inducing phase separation in the plane of DPPC bilayers, as revealed by differential scanning calorimetry (DSC). Ethylazinphos progressively depresses the transmembrane potential (DeltaPsi) of mitochondria supported by piruvate/malate, succinate, or ascorbate/TMPD. Additionally, a decreased depolarization induced by ADP depends on ethylazinphos concentration, reflecting a phosphorylation depression. This loss of phosphorylation is a consequence of a decreased DeltaPsi. A decreased respiratory control ratio is also observed, since ethylazinphos stimulates state 4 respiration and inhibits ADP-stimulated respiration (state 3). Ethylazinphos concentrations up to 100 nmol/mg mitochondrial protein increase the rate of state 4 together with a decrease in DeltaPsi, without significant perturbation of state 3 and carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP)-uncoupled respiration. For increased insecticide concentrations, the state 3 and FCCP-uncoupled respiration are inhibited to approximately the same extent. The perturbations are more pronounced when the energization is supported by pyruvate/malate and less effective when succinate is used as substrate. The present data, in association with previous DSC studies, indicate that ethylazinphos, at concentrations up to 100 nmol/mg mitochondrial protein, interacts with the lipid bilayer of mitochondrial membrane, changing the lipid organization and increasing the proton permeability of the inner membrane. The increased proton permeability explains the decreased oxidative phosphorylation coupling. Resulting disturbed ATP synthesis may significantly underlie the mechanisms of ethylazinphos toxicity, since most of cell energy in eukaryotes is provided by mitochondria.
Topics: Animals; Azinphosmethyl; Calorimetry, Differential Scanning; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; Cytoplasmic Vesicles; Dose-Response Relationship, Drug; Female; Insecticides; Intracellular Membranes; Male; Membrane Lipids; Membrane Potentials; Mitochondria, Liver; Oxidative Phosphorylation; Permeability; Protons; Rats; Rats, Sprague-Dawley
PubMed: 11559019
DOI: 10.1006/taap.2001.9246 -
Environmental Health Perspectives May 1985Male mice (Q strain) received two consecutive injections of organophosphorus insecticides: a phosphonate (trichlorfon) was combined to a thiophosphate (methylparathion)...
Male mice (Q strain) received two consecutive injections of organophosphorus insecticides: a phosphonate (trichlorfon) was combined to a thiophosphate (methylparathion) or a dithiophosphate (malathion or methylazinphos) in order to evaluate the interactions at the genetic and cytogenetic levels. No increase in chromosome damage was observed in bone marrow cells, spermatogonia, and primary spermatocytes. In a dominant lethal mutation assay, the frequency of postimplantation lethality was not significantly increased over the control level. The percentage of preimplantation losses was enhanced, probably due to a toxic effect on male germ cells.
Topics: Animals; Azinphosmethyl; Chromosome Aberrations; Drug Synergism; Female; Insecticides; Malathion; Male; Methyl Parathion; Mice; Mutagens; Reproduction; Spermatozoa; Trichlorfon
PubMed: 4029101
DOI: 10.1289/ehp.8560395 -
Biochimica Et Biophysica Acta May 1996The interaction of ethylazinphos with the physical organization of model and native membranes was investigated by means of fluorescence polarization of...
The interaction of ethylazinphos with the physical organization of model and native membranes was investigated by means of fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and of its propionic acid derivative (DPH-PA). Ethylazinphos shifts the phase transition midpoint to lower temperature values and broadens the phase transition profile of bilayers reconstituted with dimyristoyl-, dipalmitoyl- and distearoylphosphatidylcholines (DMPC, DPPC, DSPC), as detected by DPH and DPH-PA. Additionally, both probes detect significant effects of ethylazinphos in the fluid phase of the above lipid bilayers. The insecticide perturbations are more pronounced in bilayers of short-chain lipids, e.g., DMPC, in correlation with the higher partition in these membranes. On the other hand, the insecticide increases to some extent the ordering promoted by cholesterol in the fluid phase of DMPC, but high cholesterol concentrations (> or = 30 mol%) almost prevent insecticide interaction, as revealed by DPH and DPH-PA. In agreement with the results in models of synthetic lipids, the increase of intrinsic cholesterol in fluid native membranes depresses the partition values of ethylazinphos and consequently its effects.
Topics: Azinphosmethyl; Cell Membrane; Cholesterol; Diphenylhexatriene; Fluorescence Polarization; Fluorescent Dyes; Insecticides; Lipid Bilayers; Phospholipids
PubMed: 8652607
DOI: 10.1016/0005-2736(96)00012-0 -
Sensors (Basel, Switzerland) 2011An approach to an inhibition bioelectronic tongue is presented. The work is focused on development of an automated flow system to carry out experimental assays, a custom...
An approach to an inhibition bioelectronic tongue is presented. The work is focused on development of an automated flow system to carry out experimental assays, a custom potentiostat to measure the response from an enzymatic biosensor, and an inhibition protocol which allows on-line detections. A Multi-commuted Flow Analysis system (MCFA) was selected and developed to carry out assays with an improved inhibition method to detect the insecticides chlorpyrifos oxon (CPO), chlorfenvinfos (CFV) and azinphos methyl-oxon (AZMO). The system manifold comprised a peristaltic pump, a set of seven electronic valves controlled by a personal computer electronic interface and software based on LabView® to control the sample dilutions into the cell. The inhibition method consists in the injection of the insecticide when the enzyme activity has reached the plateau of the current; with this method the incubation time is avoided. A potentiostat was developed to measure the response from the enzymatic biosensor. Low limits of detection of 10 nM for CPO, CFV, and AZMO were achieved.
Topics: Acetylcholinesterase; Animals; Azinphosmethyl; Benzenesulfonates; Biosensing Techniques; Chlorpyrifos; Drosophila; Enzyme Inhibitors; Insecticides; Potentiometry; Software
PubMed: 22163822
DOI: 10.3390/s110403791