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Environmental Health Perspectives Apr 2021Inhibition of acetylcholinesterase (AChE), a biomarker of organophosphorous and carbamate exposure in environmental and occupational human health, has been commonly used...
BACKGROUND
Inhibition of acetylcholinesterase (AChE), a biomarker of organophosphorous and carbamate exposure in environmental and occupational human health, has been commonly used to identify potential safety liabilities. So far, many environmental chemicals, including drug candidates, food additives, and industrial chemicals, have not been thoroughly evaluated for their inhibitory effects on AChE activity. AChE inhibitors can have therapeutic applications (e.g., tacrine and donepezil) or neurotoxic consequences (e.g., insecticides and nerve agents).
OBJECTIVES
The objective of the current study was to identify environmental chemicals that inhibit AChE activity using and models.
METHODS
To identify AChE inhibitors rapidly and efficiently, we have screened the Toxicology in the 21st Century (Tox21) 10K compound library in a quantitative high-throughput screening (qHTS) platform by using the homogenous cell-based AChE inhibition assay and enzyme-based AChE inhibition assays (with or without microsomes). AChE inhibitors identified from the primary screening were further tested in monolayer or spheroid formed by SH-SY5Y and neural stem cell models. The inhibition and binding modes of these identified compounds were studied with time-dependent enzyme-based AChE inhibition assay and molecular docking, respectively.
RESULTS
A group of known AChE inhibitors, such as donepezil, ambenonium dichloride, and tacrine hydrochloride, as well as many previously unreported AChE inhibitors, such as chelerythrine chloride and cilostazol, were identified in this study. Many of these compounds, such as pyrazophos, phosalone, and triazophos, needed metabolic activation. This study identified both reversible (e.g., donepezil and tacrine) and irreversible inhibitors (e.g., chlorpyrifos and bromophos-ethyl). Molecular docking analyses were performed to explain the relative inhibitory potency of selected compounds.
CONCLUSIONS
Our tiered qHTS approach allowed us to generate a robust and reliable data set to evaluate large sets of environmental compounds for their AChE inhibitory activity. https://doi.org/10.1289/EHP6993.
Topics: Acetylcholinesterase; Cholinesterase Inhibitors; Humans; Insecticides; Molecular Docking Simulation
PubMed: 33844597
DOI: 10.1289/EHP6993 -
Mikrochimica Acta Feb 2022A rapid detection method is introduced for residual trace levels of triazophos in water and agricultural products using an immunoassay based on catalytic hairpin...
A rapid detection method is introduced for residual trace levels of triazophos in water and agricultural products using an immunoassay based on catalytic hairpin self-assembly (CHA). The gold nanoparticle (AuNPs) surface was modified with triazophos antibody and sulfhydryl bio-barcode, and an immune competition reaction system was established between triazophos and its ovalbumin-hapten (OVA-hapten). The bio-barcode served as a catalyst to continuously induce the CHA reaction to achieve the dual signal amplification. The method does not rely on the participation of enzymes, and the addition of fluorescent materials in the last step avoids interfering factors, such as a fluorescence burst. The emitted fluorescence was detected at 489/521 nm excitation/emission wavelengths. The detection range of the developed method was 0.01-50 ng/mL for triazophos, and the limit of detection (LOD) was 0.0048 ng/mL. The developed method correlates well with the results obtained by LC-MS/MS, with satisfactory recovery and sensitivity. In sum, the designed method is reliable and provides a new approach to detect pesticide residues rapidly and quantitatively.
Topics: Chromatography, Liquid; Gold; Immunoassay; Metal Nanoparticles; Organothiophosphates; Tandem Mass Spectrometry; Triazoles
PubMed: 35190860
DOI: 10.1007/s00604-022-05217-5 -
The Science of the Total Environment May 2020Although the toxicity of triazophos is high and it has been pulled from the market in many countries; it is still widely used and frequently detected in agricultural...
A sensitive fluorometric bio-barcodes immunoassay for detection of triazophos residue in agricultural products and water samples by iterative cycles of DNA-RNA hybridization and dissociation of fluorophores by Ribonuclease H.
Although the toxicity of triazophos is high and it has been pulled from the market in many countries; it is still widely used and frequently detected in agricultural products. While conventional analyses have been routinely used for the quantification and monitoring of triazophos residues, those for detecting low residual levels are deemed necessary. Therefore, we developed a novel and sensitive fluorometric signal amplification immunoassay employing bio-barcodes for the quantitative analysis of triazophos residues in foodstuffs and surface water. Herein, monoclonal antibodies (mAbs) attached to gold nanoparticles (AuNPs) were coated with DNA oligonucleotides (used as a signal generator), and a complementary fluorogenic RNA was used for signal amplification. The system generated detection signals through DNA-RNA hybridization and subsequent dissociation of fluorophores by Ribonuclease H (RNase H). It has to be noted that RNase H can only disintegrate the RNA in DNA-RNA duplex, but not cleave single or double-stranded DNA. Hence, with iterative cycles of DNA-RNA hybridization, sufficient strong signal was obtained for reliable detection of residues. Furthermore, this method enables quantitative detection of triazophos residues through fluorescence intensity measurements. The competitive immunoassay shows a wide linear range of 0.01-100 ng/mL with a limit of detection (LOD) of 0.0032 ng/mL. The assay substantially meets the demand for the low residue detection of triazophos residues in agricultural products and water samples. Accuracy (expressed as spiked recovery %) and coefficient of variation (CV) were ranged from 73.4% to 116% and 7.04% to 17.4%, respectively. The proposed bio-barcodes immunoassay has the advantages of being stable, reproducible, and reliable for residue detection. In sum, the present study provides a novel approach for detection of small molecules in various sample matrices.
Topics: DNA; Gold; Immunoassay; Limit of Detection; Metal Nanoparticles; Organothiophosphates; RNA; Ribonuclease H; Triazoles
PubMed: 32084695
DOI: 10.1016/j.scitotenv.2020.137268 -
Toxicology Reports 2018Pesticides are applied to control the pests indoor and outdoor; however, their remarkable amount reaches to the aquatic system through various routes like run-off,...
Pesticides are applied to control the pests indoor and outdoor; however, their remarkable amount reaches to the aquatic system through various routes like run-off, leaching, spray-drift, effluent from factories. These are reported to have negative metabolic impact on different non-target aquatic organisms like fishes. Thus, present study is aimed to evaluate the acute toxicity of two groups of pesticides, organophosphate and pyrethroid, namely triazophos and deltamethrin, respectively. The test was conducted for 96 h period in a freshwater teleost, . The LC values for triazophos and deltamethrin after 96 h treatment was found to be 0.069 mg/L and 7.33 μg/L. The deltamethrin was found to be about ten times more toxic than triazophos to the fish. In treated fish, alterations in various behavioural patterns were observed with increasing concentrations of both the pesticides as compared to control. Further, tissue specific as well as dose dependent inhibition in the acetylcholinesterase (AChE, EC 3.1.1.7) activity was found in brain, muscle and gills in exposed to both the insecticides. However, the effect was more pronounced in triazophos treated fishes than the deltamethrin. A futuristic approach on biochemical and molecular studies may throw light on the mechanism of action of these pesticides.
PubMed: 29379743
DOI: 10.1016/j.toxrep.2017.12.006 -
Foods (Basel, Switzerland) Sep 2023Pesticide residues in kumquat fruits from China, and the quality and chronic/acute intake risks in Chinese consumers, were assessed using the QuEChERS procedure and...
Pesticide residues in kumquat fruits from China, and the quality and chronic/acute intake risks in Chinese consumers, were assessed using the QuEChERS procedure and UHPLC-MS/MS and GC-MS/MS methods. Our 5-year monitoring and survey showed 90% of the 573 samples of kumquat fruits collected from two main production areas contained one or multiple residual pesticides. Overall, 30 pesticides were detected, including 16 insecticides, 7 fungicides, 5 acaricides, and 2 plant growth modulators, of which 2 pesticides were already banned. Two or more residual pesticides were discovered in 81% of the samples, and pesticide residues in 9.4% of the samples surpassed the , such as profenofos, bifenthrin, triazophos, avermectin, spirodiclofen, difenoconazole, and methidathion. The major risk factors on the safety of kumquat fruits before 2019 were profenofos, bifenthrin, and triazophos, but their over-standard frequencies significantly declined after 2019, which was credited to the stricter supervision and management policies by local governments. Despite the high detection rates and multi-residue occurrence of pesticides in kumquat fruits, about 81% of the samples were assessed as qualified. Moreover, the accumulative chronic diet risk determined from is very low. To better protect the health of customers, we shall formulate stricter organic phosphorus pesticide control measures and stricter use guidelines, especially for methidathion, triazophos, chlorpyrifos, and profenofos. This study provides potential data for the design of kumquat fruit quality and safety control guidelines and for the reduction in health risks to humans.
PubMed: 37761133
DOI: 10.3390/foods12183423 -
PloS One 2021On 4th December 2020, a sudden outbreak, with neurological symptoms like seizures, loss of consciousness etc., was reported in a town from south India. By 3rd day about...
On 4th December 2020, a sudden outbreak, with neurological symptoms like seizures, loss of consciousness etc., was reported in a town from south India. By 3rd day about 400 people were involved. A multi disciplinary team from our institute visited the site to investigate the outbreak. Based on the case history and clinical examination of the patients, the team suspected a probable diagnosis of an acute pesticide, heavy metal and/or mycotoxin exposure for which, biological samples (blood, urine) were collected from those who reported the symptoms as well as from a few who did not report symptoms (controls). To identify the source, water and food samples were collected. The samples were subjected to ICP-MS for heavy metal analysis, LC-MS/MS for pesticide analysis, microbiological analysis and ELISA-Kit method for aflatoxins if any. Clinical and dietary details were collected from a total of 112 participants, of which, 103 cases (77 active cases at Hospital and 26 recovered cases from community) and 9 were controls. A total of 109 biological samples, 36 water samples and food samples were collected. The mean age of the study participants was 29.2 years. Among cases, Seizures were seen in 84%, loss of consciousness in 66%, mental confusion in 35%, pinpoint pupil in 11%. Triazophos (organophosphate) pesticide was present in 74% of Blood samples and its metabolites were present in 98% of the urine samples collected from the cases. All the ten heavy metals investigated including lead, mercury and nickel were found to be within permissible limits except for a few samples. No presence of mycotoxins was observed in Food samples. Water samples which included Head pump and reservoir were free from pesticides; however, all water samples from households of cases had triazophos pesticide with a mean concentration of 1.00 ug/L. Thus, it was concluded that, the probable cause of outbreak was Triazophos (Organophosphate) pesticide contamination in water at the Household level. Regular surveillance for the presence of residual pesticides in soil, water and food with heightened vigour is recommended to prevent future outbreaks.
Topics: Chromatography, Liquid; Disease Outbreaks; Female; Food Contamination; Heavy Metal Poisoning; Humans; India; Male; Mycotoxins; Nervous System Diseases; Organothiophosphates; Pesticides; Tandem Mass Spectrometry; Triazoles
PubMed: 34748567
DOI: 10.1371/journal.pone.0259192 -
Toxicology Research Sep 2018Triazophos is a highly toxic organophosphorus pesticide, causing acute toxicity to brain tissue, and neurotoxicity and embryotoxicity to animals. Therefore, triazophos...
Triazophos is a highly toxic organophosphorus pesticide, causing acute toxicity to brain tissue, and neurotoxicity and embryotoxicity to animals. Therefore, triazophos is considered as a public health problem due to its acute hazard index. MicroRNAs (miRNAs), a class of endogenous noncoding RNAs, can regulate the expression of target gene(s) by mediating mRNA cleavage or translational repression in organisms exposed to environmental chemicals. We found that is targeted by , which was significantly regulated in adult zebrafish () exposed to triazophos (phenyl-1,2,4-triazolyl-3-(,-diethyl thionophosphate)). The expression of in both mRNA and protein levels was downregulated in a dose-dependent manner upon stimulation with triazophos. A dual luciferase reporter assay demonstrated that interacted with the 3'-untranslated regions (3'-UTR) of . The expression of in both mRNA and protein level was reduced in ZF4 cells when transfected with an mimic, but increased when transfected with an inhibitor. As a result, is targeted by upon triazophos exposure. We suggest that could be a potential toxicological biomarker for triazophos.
PubMed: 30310668
DOI: 10.1039/c8tx00065d -
Heliyon Jul 2020In the current investigation, bacterial strain MB497 was examined for production of intracellular and extracellular organophosphorus phosphatase (OPP) enzymes. This...
In the current investigation, bacterial strain MB497 was examined for production of intracellular and extracellular organophosphorus phosphatase (OPP) enzymes. This strain produced significant amount of extracellular acidic and alkaline phosphatases. Production of neutral phosphatase was negligible. Production of OPP was generally highest at pH 11 and at 45-50 °C. However, activity and stability of OPP was highest at 37 °C and reduced at higher temperatures. OPP production was decreased after 48 h of incubation. Largely, OPP activity was inhibited by SDS and EDTA and significantly enhanced by metals (Zn, Cu and Cd). Both acidic and alkaline OPPs were capable of bio-precipitation of selected metals (Ni, Mn, Cr and Cd) up to 86-100%. When used against 50 mg/l of three OP pesticides (Chlorpyrifos, Triazophos, and Dimethoate), 81-94.6% degradation of pesticides was observed by alkaline OPP, while acidic OPP showed less degradation (61-70.5%) within 30 min of incubation.
PubMed: 32642578
DOI: 10.1016/j.heliyon.2020.e04221 -
Food Chemistry Jun 2021Herein, a novel visual method for detecting triazophos based on competitive bio-barcode immunoassay was described. The competitive immunoassay was established by gold...
Herein, a novel visual method for detecting triazophos based on competitive bio-barcode immunoassay was described. The competitive immunoassay was established by gold nanoparticles (AuNPs), magnetic microparticle (MMPs) and triazophos, combined with biochip hybridization system to detect the residual of triazophos in water and apple. Because AuNPs carried many bio-barcodes, which hybridized with labeled DNA on the biochip, catalyzed signal amplification using silver staining was detected by grayscale values as well as the naked eye. Notably, the grayscale values decreases with increasing the concentrations of triazophos, and the color change weakened gradually. The detection range was in between 0.05 and 10 ng/mL and the minimum detection limit was set at 0.04 ng/mL. Percent recovery calculated from spiked water and apple samples ranged between 55.4 and 107.8% with relative standard deviations (RSDs) of 12.4-24.9%. It has therefore been shown that this protocol provides a new insight for rapid detection of small molecule pesticides in various matrices.
Topics: Gold; Immunoassay; Malus; Metal Nanoparticles; Organothiophosphates; Silver Staining; Triazoles; Water
PubMed: 33461115
DOI: 10.1016/j.foodchem.2021.129024 -
Scientific Reports Jun 2018White-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), one of the main agricultural insect pests in China, is resistant to a wide variety of... (Comparative Study)
Comparative Study
White-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), one of the main agricultural insect pests in China, is resistant to a wide variety of insecticides. We used transcriptome analysis to compare the expression patterns of resistance- and stress-response genes in S. furcifera subjected to imidacloprid, deltamethrin, and triazophos stress, to determine the molecular mechanisms of resistance to these insecticides. A comparative analysis of gene expression under imidacloprid, deltamethrin, and triazophos stress revealed 1,123, 841, and 316 upregulated unigenes, respectively, compared to the control. These upregulated genes included seven P450s (two CYP2 clade, three CYP3 clade, and two CYP4 clade), one GST, one ABC transporter (ABCF), and seven Hsps (one 90 and six Hsp70s) under imidacloprid stress; one P450 (CYP3 clade), two ABC transporters (one ABCF and one ABCD), and one Hsp (Hsp90) under deltamethrin stress; one P450 (CYP3 clade) and one ABC transporter (ABCF) under triazophos stress. In addition, 80 genes were commonly upregulated in response to the three insecticide treatments, including laminin, larval cuticle protein, and fasciclin, which are associated with epidermal formation. These results provide a valuable resource for the molecular characterisation of insecticide action in S. furcifera, especially the molecular characteristics of insecticide cross resistance.
Topics: Animals; Hemiptera; Insecticide Resistance; Insecticides; Neonicotinoids; Nitriles; Nitro Compounds; Organothiophosphates; Phylogeny; Pyrethrins; Transcriptome; Triazoles; Up-Regulation
PubMed: 29884844
DOI: 10.1038/s41598-018-27062-4