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Frontiers in Microbiology 2020Acephate is an organophosphate pesticide that has been widely used to control insect pests in agricultural fields for decades. However, its use has been partially... (Review)
Review
Acephate is an organophosphate pesticide that has been widely used to control insect pests in agricultural fields for decades. However, its use has been partially restricted in many countries due to its toxic intermediate product methamidophos. Long term exposure to acephate and methamidophos in non-target organisms results in severe poisonous effects, which has raised public concern and demand for the removal of these pollutants from the environment. In this paper, the toxicological effects of acephate and/or methamidophos on aquatic and land animals, including humans are reviewed, as these effects promote the necessity of removing acephate from the environment. Physicochemical degradation mechanisms of acephate and/or methamidophos are explored and explained, such as photo-Fenton, ultraviolet/titanium dioxide (UV/TiO) photocatalysis, and ultrasonic ozonation. Compared with physicochemical methods, the microbial degradation of acephate and methamidophos is emerging as an eco-friendly method that can be used for large-scale treatment. In recent years, microorganisms capable of degrading methamidophos or acephate have been isolated, including sp., , , , and Enzymes related to acephate and/or methamidophos biodegradation include phosphotriesterase, paraoxonase 1, and carboxylesterase. Furthermore, several genes encoding organophosphorus degrading enzymes have been identified, such as , , and . However, few reviews have focused on the biochemical pathways and molecular mechanisms of acephate and methamidophos. In this review, the mechanisms and degradation pathways of acephate and methamidophos are summarized in order to provide a new way of thinking for the study of the degradation of acephate and methamidophos.
PubMed: 33013750
DOI: 10.3389/fmicb.2020.02045 -
Environmental Research Nov 2023Acephate is a pesticide classified as moderately toxic, and its metabolite methamidophos is highly toxic for mammals and birds; even so, it is one of the most used... (Review)
Review
Acephate is a pesticide classified as moderately toxic, and its metabolite methamidophos is highly toxic for mammals and birds; even so, it is one of the most used insecticides in pest control for agricultural and domestic use. Acephate toxicity affects both target and non-target organisms and causes serious damage to the environment. There are several studies on different perspectives of acephate, such as monitoring, toxicity, and modeling. In this sense, this research aims to identify the structure of intellectual production on acephate and analyze the gaps and trends of scientific production on acephate through a scientometric analysis. The data was obtained from the Web of Science database, and after the refinement, 1.085 documents were used. A temporal pattern of the main research objectives is displayed. Most selected studies evaluated acephate efficiency, followed by toxicity and residue detection methods. The USA, China, India, Brazil, and Japan had the highest number of publications on acephate. The keywords most utilized were pesticides, toxicity, insecticide resistance, and residue. Research involving acephate requires greater attention from areas such as ecotoxicology, biochemistry, genetics, and biotechnology. There needed to be more discussions on chronic toxicity, genotoxicity, and cytotoxicity. Moreover, few studies about metabolic and biochemical pathways and genes related to acephate action and biodegradation were scarce.
PubMed: 37673123
DOI: 10.1016/j.envres.2023.117034 -
Chemical Research in Toxicology Sep 2022Exposure to organophosphorus pesticides (OP) can have chronic adverse effects that are independent of inhibition of acetylcholinesterase, the classic target for acute OP...
Exposure to organophosphorus pesticides (OP) can have chronic adverse effects that are independent of inhibition of acetylcholinesterase, the classic target for acute OP toxicity. In pure proteins, the organophosphorus pesticide chlorpyrifos oxon induces a cross-link between lysine and glutamate (or aspartate) with loss of water. Tubulin is particularly sensitive to OP-induced cross-linking. Our goal was to explore OP-induced cross-linking in a complex protein sample, MAP-rich tubulin from and to test 8 OP for their capacity to promote isopeptide cross-linking. We treated 100 μg of MAP-rich tubulin with 100 μM chlorpyrifos, chlorpyrifos oxon, methamidophos, paraoxon, diazinon, diazoxon, monocrotophos, or dichlorvos. Each sample was separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and stained with Coomassie blue. Five gel slices (at about 30, 50, 150, and 300 kDa, and the top of the separating gel) were removed from the lanes for each of the eight OP samples and from untreated control lanes. These gel slices were subjected to in-gel trypsin digestion. MSMS fragmentation spectra of the tryptic peptides were examined for isopeptide cross-links. Sixteen spectra yielded convincing evidence for isopeptide cross-linked peptides. Ten were from the chlorpyrifos oxon reaction, 1 from dichlorvos, 1 from paraoxon, 1 from diazinon, and 3 from diazoxon. It was concluded that catalysis of protein cross-linking is a general property of organophosphorus pesticides and pesticide metabolites. Data are available via ProteomeXchange with identifier PXD034529.
Topics: Acetylcholinesterase; Aspartic Acid; Chlorpyrifos; Diazinon; Dichlorvos; Glutamates; Lysine; Monocrotophos; Organophosphorus Compounds; Paraoxon; Peptides; Pesticides; Sodium Dodecyl Sulfate; Trypsin; Tubulin; Water
PubMed: 36048166
DOI: 10.1021/acs.chemrestox.2c00194 -
BMC Public Health Apr 2023Poisoning of children after exposure to pesticides is a major public health concern, particularly in countries with poorer urban populations, such as South Africa. This... (Review)
Review
BACKGROUND
Poisoning of children after exposure to pesticides is a major public health concern, particularly in countries with poorer urban populations, such as South Africa. This may stem from the illegal distribution and domestic use of street pesticides, which are highly hazardous agricultural pesticides. The aim of this study was to profile paediatric deaths due to acute pesticide poisoning in the west-metropole of Cape Town, South Africa; to identify whether the active ingredients were highly hazardous pesticides according to the FAO and WHO; and to inform policy and public health interventions to prevent future exposures and mortality.
METHODS
A retrospective and descriptive analysis of forensic post-mortem records (2010 to 2019) was conducted to identify cases of paediatric deaths (< 18 years old) in the west metropole of Cape Town, involving pesticide poisoning admitted to the Salt River mortuary (one out of 16 mortuaries in the Western Cape province). Demographic, circumstantial, autopsy, and toxicological information was captured. Descriptive statistics, together with chi-square tests, Fisher's probability tests, and Mann-Whitney U tests were used to analyse the data.
RESULTS
In total, 54 paediatric pesticide deaths were identified, including 22 (40.7%) males and 32 (59.3%) females, out of 5,181 paediatric unnatural deaths admitted over the 10-year period. The median age of the decedents was 8.3 years (range: 1 day to 17.9 years), with the majority under five years (42.6%) or between 15 and 18 years old (40.7%). All incidents occurred in peri-urban areas of Cape Town, with most individuals being admitted to hospital (88.9%) for a median survival time of 4.8 h. Toxicological analysis was requested in 50 cases (92.6%) with the organophosphate pesticides terbufos (n = 29), methamidophos (n = 2) and diazinon (n = 2) detected most frequently. Adolescent (15-18 years) suicides (29.6%) and accidental child deaths (< 4 years) (18.5%) were common.
CONCLUSIONS
Terbufos and methamidophos are highly hazardous pesticide (HHP) active ingredients registered in South Africa for agricultural uses, yet commonly sold as street pesticides for domestic use in lower socioeconomic areas. Reducing access and availability of toxic pesticides, especially through the illegal selling of street pesticides, and providing low toxic alternatives to poorer communities, may support mortality reduction initiatives. Mortality and toxicology data provide important, often overlooked, surveillance tools for informing policy and public health interventions to reduce toxic pesticide harm in local communities.
Topics: Adolescent; Child; Female; Humans; Infant, Newborn; Male; Pesticides; Retrospective Studies; South Africa; Suicide
PubMed: 37118778
DOI: 10.1186/s12889-023-15652-5 -
Scientific Reports Jun 2021This study analysed the clinical patterns and outcomes of elderly patients with organophosphate intoxication. A total of 71 elderly patients with organophosphate...
This study analysed the clinical patterns and outcomes of elderly patients with organophosphate intoxication. A total of 71 elderly patients with organophosphate poisoning were seen between 2008 and 2017. Patients were stratified into two subgroups: survivors (n = 57) or nonsurvivors (n = 14). Chlorpyrifos accounted for 33.8% of the cases, followed by methamidophos (12.7%) and mevinphos (11.3%). Mood, adjustment and psychotic disorder were noted in 39.4%, 33.8% and 2.8% of patients, respectively. All patients were treated with atropine and pralidoxime therapies. Acute cholinergic crisis developed in all cases (100.0%). The complications included respiratory failure (52.1%), aspiration pneumonia (50.7%), acute kidney injury (43.7%), severe consciousness disturbance (25.4%), shock (14.1%) and seizures (4.2%). Some patients also developed intermediate syndrome (15.5%) and delayed neuropathy (4.2%). The nonsurvivors suffered higher rates of hypotension (P < 0.001), shock (P < 0.001) and kidney injury (P = 0.001) than survivors did. Kaplan-Meier analysis indicated that patients with shock suffered lower cumulative survival than did patients without shock (log-rank test, P < 0.001). In a multivariate-Cox-regression model, shock was a significant predictor of mortality after intoxication (odds ratio 18.182, 95% confidence interval 2.045-166.667, P = 0.009). The mortality rate was 19.7%. Acute cholinergic crisis, intermediate syndrome, and delayed neuropathy developed in 100.0%, 15.5%, and 4.2% of patients, respectively.
Topics: Acute Kidney Injury; Affect; Aged; Antidotes; Atropine; Chlorpyrifos; Female; Humans; Insecticides; Male; Mevinphos; Middle Aged; Organophosphate Poisoning; Organothiophosphorus Compounds; Pneumonia, Aspiration; Pralidoxime Compounds; Psychotic Disorders; Respiratory Insufficiency; Retrospective Studies; Seizures; Shock; Survival Analysis; Treatment Outcome
PubMed: 34079035
DOI: 10.1038/s41598-021-91230-2 -
Environmental and Molecular Mutagenesis Jan 2022We previously showed that farmers in Bolivia are exposed to many pesticides, some at elevated levels, and that this was associated with increased risk of genetic damage....
We previously showed that farmers in Bolivia are exposed to many pesticides, some at elevated levels, and that this was associated with increased risk of genetic damage. To improve the understanding of possible mixture effects, the cytotoxicity and genotoxicity of pesticides were studied in vitro using human liver HepG2 cells. The studied pesticides were 2,4-D, chlorpyrifos, cypermethrin, glyphosate, methamidophos, paraquat, profenofos, and tebuconazole. Three mixtures (U1, U2, and U3) were based on profiles of urinary pesticide metabolites and one mixture on the most frequently used pesticides (S1). The results showed that paraquat and methamidophos were the most cytotoxic pesticides (EC ≤0.3 mM). Paraquat, chlorpyrifos, tebuconazole, and the U1, U2, and U3 mixtures, which contained a large proportion of either chlorpyrifos or tebuconazole, significantly increased intracellular ROS levels. Most pesticides activated DNA damage signaling through proteins Chk1 and H2AX. Strongest responses were elicited by paraquat, profenofos, chlorpyrifos, cypermethrin, and the S1 mixture, which contained 25% paraquat. Comet assay revealed significant increases of DNA damage in response to paraquat, cypermethrin, and U2 and S1 mixtures, which contained high levels of cypermethrin and paraquat, respectively. In summary, we showed that the tested pesticides, alone or in mixtures, in general induced oxidative stress and that most pesticides, and especially paraquat and cypermethrin, were genotoxic in HepG2 cells. We could also show that mixtures dominated by these two pesticides displayed a marked genotoxic potency, which agreed with our previous population studies.
Topics: Bolivia; Chlorpyrifos; DNA Damage; Farmers; Humans; Paraquat; Pesticides
PubMed: 34881454
DOI: 10.1002/em.22468 -
Journal of Separation Science May 2022Acephate is widely used in crops as racemate. However, the enantioselective dissipation of acephate enantiomers has not been investigated in pakchoi. A sensitive and...
Acephate is widely used in crops as racemate. However, the enantioselective dissipation of acephate enantiomers has not been investigated in pakchoi. A sensitive and effective approach was established for determining residues of acephate and its highly toxic metabolite methamidophos enantiomers by supercritical fluid chromatography tandem mass spectrometry. Baseline separations for their enantiomers were achieved by using a Chiralcel OD-H column. The optimal chromatographic conditions were obtained as follows: CO /ethanol (95/5) as mobile phase; flow rate, 3.0 mL/min; column temperature, 40°C. The mean recoveries (RSDs) of analytes were in the range of 77-83.1% (6.1-9.9%), 75.4-87.5% (9.3-13.2%), and 81.5-84.2% (7.1-13.4%) at three fortification levels (0.005, 0.05, and 0.5 mg/kg for each enantiomer) for interday assay (n = 18). The method was used to evaluate the enantioselective dissipation of acephate and methamidophos in pakchoi. S-acephate dissipated faster than R-acephate, while the concentration of R-methamidophos was higher than that of S-methamidophos during the entire study period. The results indicated that the R-enantiomer of acephate and methamidophos was preferentially enriched in pakchoi. The established analysis approach and the study data provided useful information for the rational use of acephate in agriculture.
Topics: Chromatography, Supercritical Fluid; Insecticides; Organothiophosphorus Compounds; Phosphoramides; Stereoisomerism; Tandem Mass Spectrometry
PubMed: 35261148
DOI: 10.1002/jssc.202200006 -
Journal of UOEH 2021We gave mice a 540 mg/kg dose of LD50 acephate, followed by an assessment of acephate, methamidophos (MP), and choline esterase (ChE) activity for up to 4 hours (hr) in...
We gave mice a 540 mg/kg dose of LD50 acephate, followed by an assessment of acephate, methamidophos (MP), and choline esterase (ChE) activity for up to 4 hours (hr) in order to investigate the time course of acephate intoxication. At 1 hr, the blood acephate and MP levels were 428 ± 90 µg/ml (mean ± SEM) and 4.2 ± 0.4 µg/ ml, respectively. The liver acephate levels were similar to those in the blood, but the liver MP levels were approximately 3.5 times that of the blood at 1 hr. The brain MP level tended to be higher than the blood MP at 1 hr. These levels decreased gradually over 4 hr, but the brain acephate and MP levels surpassed the blood levels significantly at 4 hr, and after 2 hr, respectively. Serum, liver, cerebrum, cerebellum, and brainstem cholinesterase activity (ChE) were inhibited at 1 hr, and remained inhibited in all but the cerebellum until the end of the experiment. The obtained data were applied to previously reported autopsy cases of acephate intake. Experimental data suggest that brain MP is involved in acute acephate-induced poisoning, even after a reduction in blood acephate. In autopsy cases with suspected acephate poisoning, the MP level in the brain should be considered in addition to the ChE activity to diagnose the cause of death.
Topics: Animals; Brain; Cholinesterase Inhibitors; Insecticides; Mice; Organothiophosphorus Compounds; Phosphoramides
PubMed: 34092764
DOI: 10.7888/juoeh.43.197 -
Journal of Analytical Toxicology Feb 2022The presence and use of carbamate and organophosphate pesticides with agricultural and urban purposes in Colombia has been justified for pest control. However, these...
Determination of Aldicarb, Carbofuran and Methamidophos in Blood Derived from Forensic Cases through Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry (LC--ESI-MS-MS).
The presence and use of carbamate and organophosphate pesticides with agricultural and urban purposes in Colombia has been justified for pest control. However, these substances pose a national problem because of their toxic nature, which is associated with accidental poisoning or even with homicides or suicides related to acute fatal poisoning. This study aims to develop and to validate an analytical methodology for the determination of the aldicarb, carbofuran and methamidophos pesticides in blood through liquid chromatography--tandem mass spectrometry (LC-MS-MS). To this end, the method for extracting pesticides from the blood was developed, the conditions of LC were defined, the instrumental system MS-MS was optimized and the bioanalytical methodology was validated. This methodology proved to be selective, precise, accurate and linear in the concentration range from 0.10 to 5.0 µg/mL, with a limit of detection of 0.020 µg/mL for aldicarb and carbofuran and 0.050 µg/mL for methamidophos, recovery between 90% and 102%, and stability at room temperature and in the autosampler between 80% and 120%. The analytical methodology was applied to 34 forensic cases. Carbofuran was found at a concentration ranging from 0.020 to >5.0 µg/mL, aldicarb was found at a concentration ranging from 0.10 to 2.5 µg/mL and methamidophos was found at a concentration >5.0 µg/mL. In 62% of the cases, the pesticides under study were used to commit suicide. Necropsy findings of pesticide poisoning are non-specific. Therefore, toxicological blood analysis provides significant information at the forensic level, and the analytical method validated represents a sensitive, fast and reliable analysis with little solvent consumption of a small sample amount, so it is suitable for routine application in fatal pesticide poisonings.
Topics: Aldicarb; Carbofuran; Chromatography, Liquid; Humans; Organothiophosphorus Compounds; Spectrometry, Mass, Electrospray Ionization; Suicide; Tandem Mass Spectrometry
PubMed: 33258956
DOI: 10.1093/jat/bkaa182 -
International Journal of Legal Medicine May 2017Poisoning by organophosphorus insecticides such as methamidophos makes up a significant portion of forensic identification cases in China. Stability of methamidophos...
Poisoning by organophosphorus insecticides such as methamidophos makes up a significant portion of forensic identification cases in China. Stability of methamidophos during specimen storage remains largely unknown. This study aimed to examine the long-term stability of methamidophos in postmortem specimens. Three experimental dogs after oral administration of methamidophos were sacrificed, and blood and liver specimens were collected and stored at various conditions. Gas chromatography-mass spectrometry (GC/MS) was used to measure the methamidophos concentrations after 0, 4, 7, 12, 16, 60, and 180 days of storage. The results showed that methamidophos was not stable and followed first-order degradation kinetics at all storage conditions investigated. The degradation half-life in blood was 12.2, 16.9, 11.0, and 1.0 days when the samples were stored at room temperature (RT, 20 °C), 4 °C, -20 °C, and at RT with 1 % sodium fluoride (NaF), respectively. The degradation half-life in liver was 4.1, 9.8, 17.8, and 2.0 days when the samples were stored at RT, 4 °C, -20 °C, and at RT with liver fixed in 10 % formaldehyde solution, respectively. These findings are significant in guiding sample storage and data interpretation. Specimens containing methamidophos should be stored at -20 °C and analyzed as early as possible. Addition of NaF in blood and fixation of liver in formaldehyde should be avoided due to the accelerated degradation of methamidophos under these conditions. The preliminary study suggests that it might be possible to calculate methamidophos concentration at the time of death based on its first-order degradation kinetic under specific storage conditions.
Topics: Animals; Dogs; Drug Stability; Fixatives; Forensic Toxicology; Formaldehyde; Half-Life; Insecticides; Liver; Organothiophosphorus Compounds; Sodium Fluoride; Specimen Handling; Temperature
PubMed: 27990599
DOI: 10.1007/s00414-016-1518-x