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Environmental Toxicology May 2012Dicrotophos is a systemic insecticide with a wide range of applications. We investigated the genotoxicity of dicrotophos using the Ames test, the chromosome aberration...
Dicrotophos is a systemic insecticide with a wide range of applications. We investigated the genotoxicity of dicrotophos using the Ames test, the chromosome aberration test in CHO-K1 cells, and the comet assay in the Hep G2 cells, while this chemicals' toxicity to both the cell lines was evaluated with the MTT assay. Results showed that dicrotophos did not show any cytotoxicity to CHO-K1 cells, whereas it was cytotoxic to HepG2 cells incubated for 24 h but not for 2 h. For genotoxicity of dicrotophos, a significant change in the numbers of bacterial reveratnts using Salmomella typhimurium TA97a, TA98, TA100, TA102, and TA1535 as the tester strains, an increase in the frequencies of chromosome aberration in CHO-K1 cells, and an induced DNA damage in HepG2 cells were observed, indicating that dicrotophos was genotoxic in these three performed assays. From this study, we provide further evidence towards of genotoxic effects of dicrotophos.
Topics: Animals; CHO Cells; Chromosome Aberrations; Comet Assay; Cricetinae; Cricetulus; DNA Damage; Hep G2 Cells; Humans; Insecticides; Mutagenicity Tests; Mutagens; Organophosphorus Compounds; Salmonella typhimurium
PubMed: 22499550
DOI: 10.1002/tox.20645 -
Journal of Economic Entomology Apr 2018To assess the toxicity of bifenthrin and four mixtures of insecticides to tarnished plant bug, we used an insecticide dip method of green bean to treat adults of a...
To assess the toxicity of bifenthrin and four mixtures of insecticides to tarnished plant bug, we used an insecticide dip method of green bean to treat adults of a laboratory colony; mortality was assessed after 48 h. LC50s for imidacloprid, bifenthrin, acephate, thiamethoxam, and dicrotophos were 0.12, 0.39, 0.62, 0.67, and 3.96 ppm, respectively. LC75s for imidacloprid, bifenthrin, acephate, thiamethoxam, and dicrotophos were 0.61, 4.22, 5.10, 2.65, and 7.86 ppm, respectively. Based on the LC50s and LC75s, dicrotophos was much less toxic than the other chemicals tested. PoloMix software was used to determine syngerism, antagonism, or addition effects of the mixtures. Three out of four analyses of the joint action of bifenthrin plus imidacloprid or acephate or dicrotophos showed that toxicity was not independent and not correlated. For bifenthrin plus dicrotophos, observed mortality was greater than expected mortality at most concentrations suggesting synergism. Mixtures of bifenthrin plus imidacloprid and bifenthrin plus acephate showed observed mortality significantly less than expected, suggesting antagonism. LC50s for bifenthrin plus dicrotophos, acephate, imidacloprid, and thiamethoxam were 0.38, 1.06, 0.17, and 0.26 ppm, respectively. LC75s for bifenthrin plus dicrotophos, acephate, imidacloprid, and thiamethoxam were 13.61, 13.18, 0.67, and 0.80 ppm, respectively. Based on the LC50s and LC75s, bifenthrin plus acephate was 3- to 10-fold less toxic than the other chemicals tested. Bifenthrin plus acephate is frequently used in tank mixes to control tarnished plant bug and other cotton pests, and the effectiveness of each individual chemical appears to be reduced in one to one ratio mixtures.
Topics: Animals; Heteroptera; Insecticide Resistance; Insecticides; Neonicotinoids; Nitro Compounds; Organophosphorus Compounds; Organothiophosphorus Compounds; Oxazines; Phosphoramides; Pyrethrins; Thiamethoxam; Thiazoles
PubMed: 29361174
DOI: 10.1093/jee/tox341 -
Chemosphere Sep 2016Insecticide resistance is usually associated with pests, but may also evolve in natural enemies. In this study, adult beetles of three distinct North American...
Insecticide resistance is usually associated with pests, but may also evolve in natural enemies. In this study, adult beetles of three distinct North American populations of Hippodamia convergens Guérin-Méneville, and the progeny of reciprocal crosses between the resistant and most susceptible population, were treated topically with varying concentrations of lambda-cyhalothrin and dicrotophos. In addition, the LD50s of both insecticides were applied in combination to resistant individuals. The developmental and reproductive performance of each population was assessed in the absence of insecticide exposure to compare baseline fitness. California and Kansas populations were susceptible to both materials, whereas Georgia (GA) beetles exhibited a resistance ratio (RR50) of 158 to lambda-cyhalothrin and 530 to dicrotophos. Inheritance of lambda-cyhalothrin resistance was X-linked, whereas inheritance of dicrotophos resistance was autosomal. Mortality of resistant beetles treated with a mixture of LD50s of both materials was twice that of those treated with lambda-cyhalothrin alone, but not significantly different from those receiving dicrotophos alone. Life history parameters were largely similar among populations, except that Georgia beetles had higher egg fertility relative to susceptible populations. We conclude that the high levels of resistance to lambda-cyhalothrin and dicrotophos in Georgia beetles reflect heavy loads of these insecticides in local environments, most likely the large acreage under intensive cotton cultivation.
Topics: Animals; California; Coleoptera; Female; Fertility; Georgia; Insecticide Resistance; Insecticides; Kansas; Male; Nitriles; Organophosphorus Compounds; Pyrethrins
PubMed: 27266835
DOI: 10.1016/j.chemosphere.2016.05.075 -
Current Pharmaceutical Design 2017Reversible cholinesterase inhibitors, when given prophylactically before exposure to organophosphates, are able to decrease organophosphate-induced mortality. However,...
BACKGROUND
Reversible cholinesterase inhibitors, when given prophylactically before exposure to organophosphates, are able to decrease organophosphate-induced mortality. However, the efficacy of pyridostigmine, the only pre-treatment substance approved by the US Federal Drug Administration, is unsatisfactory.
METHODS
In search of a better prophylactic compound, we determined in vivo the protection conferred by five cholinesterase inhibitors (ranitidine, physostigmine, tacrine, K-27 and pyridostigmine), which were administered in equitoxic dosage (1/4 of LD01) 30 minutes before exposure to the organophosphate dicrotophos. Efficacy was measured in rats by Cox analysis calculating the relative risk of death (RR), RR being 1 for the reference group which received dicrotophos and no prophylaxis.
RESULTS
K-27 (RR=0.06), physostigmine (RR=0.15), pyridostigmine (RR=0.22) and tacrine (RR=0.28) significantly (p ≤ 0.05) reduced dicrotophos-induced mortality in comparison to the reference group (dicrotophos without pre-treatment), whereas ranitidine (RR=0.86) had no significant influence. The experimental oxime K-27, when given before dicrotophos exposure, conferred the best in vivo protection. This was significantly (p ≤ 0.05) more efficacious than pre-treatment with any other tested compound. The differences in efficacy between the second best compound, physostigmine, and the less efficacious substances (tacrine and pyridostigmine) were also statistically significant.
CONCLUSION
These data indicate that K-27 can be considered a very efficacious prophylactic agent for organophosphate exposure.
Topics: Animals; Cholinesterase Inhibitors; Female; Humans; Male; Organophosphates; Organophosphorus Compounds; Oximes; Pre-Exposure Prophylaxis; Pyridinium Compounds; Rats; Rats, Wistar; Survival Rate; Treatment Outcome
PubMed: 27799040
DOI: 10.2174/1381612822666161027154303 -
Neurotoxicology and Teratology 2011Age-related differences in the acute neurotoxicity of cholinesterase (ChE)-inhibiting pesticides have been well-studied for a few organophosphates, but not for many...
Age-related differences in the acute neurotoxicity of cholinesterase (ChE)-inhibiting pesticides have been well-studied for a few organophosphates, but not for many others. In this study, we directly compared dose-responses using brain and red blood cell (RBC) ChE measurements, along with motor activity, for mevinphos, monocrotophos, dicrotophos, and phosphamidon. Long-Evans hooded male rats were tested as adults and at postnatal day (PND) 17; PND11 pups were also tested with dicrotophos only. All chemicals were administered via oral gavage and tests were conducted at times intended to span peak behavioral and ChE effects. All OPs tested produced a rapid onset and recovery from the behavioral effects. There were age-related differences in the inhibition of brain, but not necessarily RBC, ChE. Mevinphos was clearly more toxic, up to 4-fold, to the young rat. On the other hand, monocrotophos, dicrotophos, and phosphamidon were somewhat more toxic to the young rat, but the magnitude of the differences was < 2-fold lower. Motor activity was consistently decreased in adults for all chemicals tested; however, there was more variability with the pups and clear age-related differences were only observed for mevinphos. These data show that three of these four OPs were only moderately more toxic in young rats, and further support findings that age-related differences in pesticide toxicity are chemical-specific.
Topics: Aging; Animals; Animals, Newborn; Behavior, Animal; Brain; Cholinesterase Inhibitors; Cholinesterases; Dose-Response Relationship, Drug; Erythrocytes; Male; Mevinphos; Monocrotophos; Motor Activity; Neurotoxicity Syndromes; Organophosphorus Compounds; Pesticides; Phosphamidon; Rats; Rats, Long-Evans
PubMed: 21679767
DOI: 10.1016/j.ntt.2011.05.012 -
Journal of Wildlife Diseases Jul 2012Common Quail (Coturnix coturnix) were subjected to controlled and replicated experiments in the summer of 2008 to investigate the effects of short-term dehydration on...
Combined effect of short-term dehydration and sublethal acute oral dicrotophos exposure confounds the diagnosis of anticholinesterase exposure in common quail (Coturnix coturnix) using plasma cholinesterase activity.
Common Quail (Coturnix coturnix) were subjected to controlled and replicated experiments in the summer of 2008 to investigate the effects of short-term dehydration on cholinesterase activity in brain and plasma and the interaction between dehydration and exposure to the organophosphorus pesticide dicrotophos in these same tissues. Our objective was to determine if dehydration could confound the diagnosis of anticholinesterase exposure using inhibition of cholinesterase activity in quail tissues. The effect of dehydration was quantified using measures of plasma osmolality and hematocrit. Dicrotophos exposure caused significant inhibition of cholinesterase activity in brain, while the effects of dehydration and interaction were not significant. Dehydration caused significant duration-dependent increases in plasma osmolality and hematocrit. Dehydration also caused a significant increase in plasma cholinesterase activity. Variation in the change in plasma cholinesterase activity in response to dehydration was significantly and positively correlated with dehydration-induced variation in both the change in plasma osmolality and the change in hematocrit. These correlations suggest that plasma cholinesterase activity in quail is not limited to plasma but occupies some larger pool of the extracellular fluid volume, and we suggest lymph is part of that pool. The effects of dehydration on plasma cholinesterase activity masked the inhibitory effects of dicrotophos. Here, the combination of dehydration and dicrotophos exposure produced plasma cholinesterase activity that was not significantly different from reference and pre-exposure values, confounding the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail. A method to adjust plasma cholinesterase activities for the confounding effects of dehydration and enable the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail was developed. Clinicians and practitioners responsible for the diagnosis of anticholinesterase exposure in birds are cautioned that dehydration, commonly observed in sick wildlife, may mask the effect of anticholinesterases on plasma cholinesterase activity.
Topics: Animals; Bird Diseases; Brain; Cholinesterase Inhibitors; Coturnix; Dehydration; Environmental Exposure; Female; Hematocrit; Insecticides; Male; Organophosphorus Compounds; Osmolar Concentration
PubMed: 22740535
DOI: 10.7589/0090-3558-48.3.695 -
Journal of Economic Entomology Jun 2005Certain neonicotinoids are used in cotton, Gossypium hirsutum (L.), to control various piercing-sucking pests. We conducted field studies using three neonicotinoids...
Certain neonicotinoids are used in cotton, Gossypium hirsutum (L.), to control various piercing-sucking pests. We conducted field studies using three neonicotinoids (acetamiprid, thiamethoxam, and imidacloprid) and an organophosphate (dicrotophos) to assess the activity of these insecticides against nontarget arthropods, particularly predators, and to determine the potential economic consequences of such activity. Mortality among populations of the big-eyed bug, Geocoris punctipes (Say), and the red imported fire ant, Solenopsis invicta Buren, was highest after thiamethoxam and dicrotophos treatments. Numbers of arachnids were consistently lower after dicrotophos treatments, whereas none of the neonicotinoids caused appreciable mortality. Total predators in pooled data from five separate studies revealed that numbers, compared with untreated plots, were reduced by -75% in dicrotophos, 55-60% in thiamethoxam, and only 30% in both acetamiprid and imidacloprid plots. Acetamiprid and thiamethoxam exhibited significant mortality against field-deposited eggs of bollworm, Helicoverpa zea (Boddie). Both thiamethoxam and dicrotophos plots exhibited bollworm numbers that were approximately three times higher than treatment thresholds (three per 100 plants), whereas numbers in untreated plots were below threshold levels. In one study on Bt cotton, a significant negative correlation was observed between numbers of predators and bollworm larvae. Results demonstrated that neonicotinoids differ in activity against predaceous arthropods and bollworm eggs and that high predator mortality can result in resurgence of bollworm larvae and additional insecticide costs.
Topics: Animals; Arthropods; Gossypium; Heterocyclic Compounds, 1-Ring; Insect Control; Insecticides; Lepidoptera; Organophosphorus Compounds; Ovum
PubMed: 16022310
DOI: 10.1603/0022-0493-98.3.814 -
Journal of Applied Toxicology : JAT Jan 2019Organophosphorus compounds (OPCs), inhibitors of acetylcholinesterase (AChE), are useful agents as pesticides, but also represent a serious health hazard. Standard... (Review)
Review
Organophosphorus compounds (OPCs), inhibitors of acetylcholinesterase (AChE), are useful agents as pesticides, but also represent a serious health hazard. Standard therapy with atropine and established oxime-type enzyme reactivators (pralidoxime, obidoxime) is unsatisfactory. Better therapeutic results are obtained, when reversible AChE inhibitors are administered before OPC exposure. This review summarizes the history of such a pretreatment approach and sums up a set of experiments undertaken in search of compounds that are efficacious when given before a broad range of OPCs. The prophylactic efficacy of 10 known AChE inhibitors, either already used clinically for different indications (physostigmine, pyridostigmine, ranitidine, tiapride, tacrine, amiloride, metoclopramide, methylene blue) or developed for possible therapeutic use in the future (7-methoxytacrine, K-27) was compared, when administered before exposure to six chemically diverse OPCs in the same experimental setting: ethyl-paraoxon, methyl-paraoxon, diisopropylfluorophosphate, terbufos sulfone, azinphos-methyl and dicrotophos. The experimental oxime K-27 was the most efficacious compound, affording best protection, when administered before terbufos sulfone, azinphos-methyl and dicrotophos, second best before ethyl- and methyl-paraoxon exposure and third best before diisopropylfluorophosphate administration. This ranking was similar to that of physostigmine, which was superior to the Food and Drug Administration-approved pretreatment for soman with pyridostigmine. Tiapride, amiloride, metoclopramide, methylene blue and 7-methoxytacrine did not achieve protection. No correlation was observed between the IC of the reversible AChE inhibitors and their protective efficacy. These studies indicate that K-27 can be considered a very promising broad-spectrum prophylactic agent in case of imminent organophosphate exposure, which may be related to its AChE reactivating activity rather than its AChE inhibition.
Topics: Animals; Cholinesterase Inhibitors; Humans; Models, Animal; Organophosphate Poisoning; Organophosphates; Pre-Exposure Prophylaxis
PubMed: 30027640
DOI: 10.1002/jat.3662 -
The Anatomical Record Nov 1985White Leghorn chicken eggs, specific pathogen free, were treated with the organophosphate insecticide dicrotophos and the early defects thus induced were characterized...
White Leghorn chicken eggs, specific pathogen free, were treated with the organophosphate insecticide dicrotophos and the early defects thus induced were characterized histologically. Eggs were incubated for 24, 48, 72, or 96 hr, injected with doses of dicrotophos ranging from 250 micrograms to 2.0 mg per egg, and observed after an additional 48 hr of incubation. Treated embryos displayed general developmental retardation as well as unilateral retardation of the cranial sense organs, the youngest embryos being most severely affected. Many embryos injected with insecticide at 24 hr, and all but one injected at 48 or 72 hr, displayed notochordal folding, usually restricted to the cervical region; most of these also showed deformities of the adjacent spinal cord. Other defects, seen on a less consistent basis, included branching of the neural canal in the lumbar region, bifurcation of the neural epiphysis, deformation of the lens vesicle, and distention of the major blood vessels. The incidence and severity of epiphyseal, lens, and vascular defects were greatest among embryos treated at 24 hr, whereas notochordal and both types of neural defects were greatest among those treated at 48 hr. The incidence and severity of the abnormalities diminished with increasing age such that by 96 hr the only defect noted was a weak notochordal folding in one embryo. To a lesser extent, incidence and severity were dose-related also. Histological similarities between embryos displaying vascular distention and recently dead treated embryos suggested that this abnormality is a precursor to death.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Blood Vessels; Chick Embryo; Epiphyses; Female; Fetal Growth Retardation; Insecticides; Lens, Crystalline; Nervous System Malformations; Notochord; Organophosphorus Compounds; Pregnancy; Prenatal Exposure Delayed Effects; Time Factors
PubMed: 3840961
DOI: 10.1002/ar.1092130312 -
Talanta Oct 1997A simple, sensitive and rapid differential pulse polarographic method has been developed for the quantitative determination of organophosphorus pesticides such as...
A simple, sensitive and rapid differential pulse polarographic method has been developed for the quantitative determination of organophosphorus pesticides such as dicrotophos, crotoxyphos and chlorfenvinphos in agricultural formulations in universal buffers of a pH range 2.0-12.0. The sample is treated with ethanol to facilitate the dissolution of these pesticides. Both standard addition and calibration methods can be used for the analyses. The lower detection limits are 1.25x10(-9), 1.05x10(-9) and 1.0x10(-9) M, respectively. The method can be applied successfully to determination of these pesticides in grains and soil.
PubMed: 18966927
DOI: 10.1016/S0039-9140(97)00081-7