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Archives of Toxicology May 2023The current approach for the risk assessment of chemicals does not account for the complex human real-life exposure scenarios. Exposure to chemical mixtures in everyday...
The current approach for the risk assessment of chemicals does not account for the complex human real-life exposure scenarios. Exposure to chemical mixtures in everyday life has raised scientific, regulatory, and societal concerns in recent years. Several studies aiming to identify the safety limits of chemical mixtures determined hazardous levels lower than those of separate chemicals. Following these observations, this study built on the standards set by the real-life risk simulation (RLRS) scenario and investigated the effect of long-term exposure (18 months) to a mixture of 13 chemicals (methomyl, triadimefon, dimethoate, glyphosate, carbaryl, methyl parathion, aspartame, sodium benzoate, EDTA, ethylparaben, butylparaben, bisphenol A and acacia gum) in adult rats. Animals were divided into four dosing groups [0xNOAEL (control), 0.0025xNOAEL (low dose-LD), 0.01xNOAEL (medium dose-MD) and 0.05xNOAEL (high dose-HD) (mg/kg BW/day)]. After 18 months of exposure, all animals were sacrificed, and their organs were harvested, weighed, and pathologically examined. While organ weight tended to be higher in males than in females, when sex and dose were taken into account, lungs and hearts from female rats had significantly greater weight than that of males. This discrepancy was more obvious in the LD group. Histopathology showed that long-term exposure to the chemical mixture selected for this study caused dose-dependent changes in all examined organs. The main organs that contribute to chemical biotransformation and clearance (liver, kidneys, and lungs) consistently presented histopathological changes following exposure to the chemical mixture. In conclusion, exposure to very low doses (below the NOAEL) of the tested mixture for 18 months induced histopathological lesions and cytotoxic effects in a dose and tissue-dependent manner.
Topics: Male; Humans; Rats; Female; Animals; No-Observed-Adverse-Effect Level; Rats, Sprague-Dawley; Pesticides; Food Additives; Organ Size
PubMed: 36892595
DOI: 10.1007/s00204-023-03455-x -
Toxics Jan 2023Methyl parathion (MP) has been widely used as an organophosphorus pesticide for food preservation and pest management, resulting in its accumulation in the aquatic...
Methyl parathion (MP) has been widely used as an organophosphorus pesticide for food preservation and pest management, resulting in its accumulation in the aquatic environment. However, the early developmental toxicity of MP to non-target species, especially aquatic vertebrates, has not been thoroughly investigated. In this study, zebrafish embryos were treated with 2.5, 5, or 10 mg/L of MP solution until 72 h post-fertilization (hpf). The results showed that MP exposure reduced spontaneous movement, hatching, and survival rates of zebrafish embryos and induced developmental abnormalities such as shortened body length, yolk edema, and spinal curvature. Notably, MP was found to induce cardiac abnormalities, including pericardial edema and decreased heart rate. Exposure to MP resulted in the accumulation of reactive oxygen species (ROS), decreased superoxide dismutase (SOD) activity, increased catalase (CAT) activity, elevated malondialdehyde (MDA) levels, and caused cardiac apoptosis in zebrafish embryos. Moreover, MP affected the transcription of cardiac development-related genes (, , , , , ) and apoptosis-related genes (, , ). Astaxanthin could rescue MP-induced heart development defects by down-regulating oxidative stress. These findings suggest that MP induces cardiac developmental toxicity and provides additional evidence of MP toxicity to aquatic organisms.
PubMed: 36668810
DOI: 10.3390/toxics11010084 -
Sensors (Basel, Switzerland) Dec 2022In this study, nanostructured gold was successfully prepared on a bare Au electrode using the electrochemical deposition method. Nanostructured gold provided more...
In this study, nanostructured gold was successfully prepared on a bare Au electrode using the electrochemical deposition method. Nanostructured gold provided more exposed active sites to facilitate the ion and electron transfer during the electrocatalytic reaction of organophosphorus pesticide (methyl parathion). The morphological and structural characterization of nanostructured gold was conducted using field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), which was further carried out to evaluate the electrocatalytic activity towards methyl parathion sensing. The electrochemical performance of nanostructured gold was investigated by electrochemical measurements (cyclic voltammetry (CV) and differential pulse voltammetry (DPV)). The proposed nanostructured gold-modified electrode exhibited prominent electrochemical methyl parathion sensing performance (including two linear concentration ranges from 0.01 to 0.5 ppm (R = 0.993) and from 0.5 to 4 ppm (R = 0.996), limit of detection of 5.9 ppb, excellent selectivity and stability), and excellent capability in determination of pesticide residue in real fruit and vegetable samples (bok choy and strawberry). The study demonstrated that the presented approach to fabricate a nanostructured gold-modified electrode could be practically applied to detect pesticide residue in agricultural products via integrating the electrochemical and gas chromatography coupled with mass spectrometry (GC/MS-MS) analysis.
Topics: Methyl Parathion; Pesticides; Organophosphorus Compounds; Gold; Pesticide Residues; Nanocomposites; Electrodes; Electrochemical Techniques; Limit of Detection; Metal Nanoparticles
PubMed: 36560305
DOI: 10.3390/s22249938 -
ACS Omega Dec 2022Pesticide usage is one of the significant issues in modern agricultural practices; hence, monitoring pesticide content and its degradation is of utmost importance. A...
Pesticide usage is one of the significant issues in modern agricultural practices; hence, monitoring pesticide content and its degradation is of utmost importance. A novel and simple one-pot deep eutectic solvent-based solvothermal method has been developed for the synthesis of FeVO/reduced graphene oxide (FeV/RGO) nanocomposite. The band gap of FeV decreased upon anchoring with RGO. Enhanced activity in the detection and photocatalytic degradation has been achieved in the FeV/RGO nanocomposite compared to pure FeV and RGO. FeV/RGO was used to modify glassy carbon electrode (GCE), and the fabricated electrode was evaluated for its electrochemical detection of methyl parathion (MP). The amperometric technique was found to be more sensitive with a 0.001-260 μM (two linear ranges; 0.001-20 and 25-260 μM) wide linear range and low limit of detection value (0.70 nM). The practical applicability of modified GCE is more selective and sensitive to real samples like river water and green beans. Photocatalytic degradation of MP has been examined using FeV, RGO, and FeV/RGO nanocomposite. FeV/RGO managed to degrade 95% of MP under solar light in 80 min. Degradation parameters were optimized carefully to attain maximum efficiency. Degradation intermediates were identified using liquid chromatography-mass spectrometry analysis. The degradation mechanism has been studied in detail. FeV/RGO could serve as a material of choice in the field of electrochemical sensors as well as heterogeneous catalysis toward environmental remediation.
PubMed: 36530306
DOI: 10.1021/acsomega.2c05729 -
Toxicological Sciences : An Official... Feb 2023High-fidelity nonanimal screening methods are needed that can rapidly and accurately characterize organophosphorus compound (OP)-induced neurotoxicity. Herein, the...
High-fidelity nonanimal screening methods are needed that can rapidly and accurately characterize organophosphorus compound (OP)-induced neurotoxicity. Herein, the efficacy of human neuroblastoma cell line (SH-SY5Y) to provide molecular and cellular responses characteristic of the OP neurotoxicity pathway was investigated in response to the OP-model compound, ethyl-parathion. Undifferentiated SH-SY5Y cells were exposed to ethyl-parathion for 30 min at 0 (control), 0.5, 2.5, 5, 10, and 25 µg/ml. Dose-responsive reductions in cell viability were observed with significant reductions at ≥10 µg/ml. From these results, ethyl-parathion exposures of 0 (control), 5, and 10 µg/ml were selected to examine bioindicators underlying the OP neurotoxicity pathway including: reactive oxygen species (ROS), cell membrane peroxidation, mitochondrial membrane potential (MMP), and apoptosis. Ethyl-parathion elicited highly significant increases in ROS relative to controls (p < .01) at both exposure concentrations, confirmed using N-acetyl cysteine (NAC) as a ROS quencher which alleviated ROS increases. A response characteristic of increased ROS exposure, cell membrane-lipid peroxidation, significantly increased (p < .05) at the highest ethyl-parathion exposure (10 µg/ml). As a likely consequence of membrane-lipid peroxidation, ethyl-parathion-induced reductions in MMP were observed with significant effects at 10 µg/ml, reducing MMP by 58.2%. As a culmination of these cellular-damage indicators, apoptosis progression was investigated by phosphatidylserine translocation where ethyl-parathion-induced dose-responsive, highly significant (p < .01) increases at both 5 and 10 µg/ml. Overall, the mechanistic responses observed in undifferentiated SH-SY5Y cells corresponded with in vivo mammalian results demonstrating potential for this nonanimal model to provide accurate OP neurotoxicology screening.
Topics: Humans; Reactive Oxygen Species; Parathion; Cell Line, Tumor; Neuroblastoma; Apoptosis; Neurotoxicity Syndromes; Cell Survival
PubMed: 36458919
DOI: 10.1093/toxsci/kfac125 -
RSC Advances Oct 2022Zr(CUR)/NiCoS/CuCoS and Zr(CUR)/CuCoS/AgS ternary composites were synthesized as efficient photocatalysts, and well characterized through XRD, FTIR, DRS, FE-SEM, EDS,...
Performance evaluation of Zr(CUR)/NiCoS/CuCoS and Zr(CUR)/CuCoS/AgS composites for photocatalytic degradation of the methyl parathion pesticide using a spiral-shaped photocatalytic reactor.
Zr(CUR)/NiCoS/CuCoS and Zr(CUR)/CuCoS/AgS ternary composites were synthesized as efficient photocatalysts, and well characterized through XRD, FTIR, DRS, FE-SEM, EDS, and EDS mapping techniques. The potential of a spiral-shaped photocatalytic reactor was evaluated for degradation of the methyl parathion (MP) pesticide using synthesized photocatalysts under visible light irradiation. Computational fluid dynamics (CFD) was applied for analysis of the hydrodynamics behaviour and mass transport occurring inside the reactor. The experiments were performed based on a developed CCD-RSM model, while the desirability function (DF) was used for optimization of the process. Findings showed that the highest MP degradation percentage was 98.70% at optimal operating values including 20 mg L, 0.60 g L, 8 and 40 min for MP concentration, catalyst dosage, pH, and reaction time, respectively. This study clearly demonstrated that high degradation efficiency can be achieved using a spiral-shaped photocatalytic reactor rather than a traditional annular reactor at same conditions. The increase in reaction rate is related to the higher average turbulence kinetic energy in the spiral-shaped reactor over the traditional reactor, which results in the increased diffusivity and improves the mass and momentum transfer.
PubMed: 36320776
DOI: 10.1039/d2ra06277a -
New Biotechnology Dec 2022In Escherichia coli, acyl carrier protein (ACP) is posttranslationally converted into its active holo-ACP form via covalent linkage of 4'-phosphopantetheine (4'-PP) to...
In Escherichia coli, acyl carrier protein (ACP) is posttranslationally converted into its active holo-ACP form via covalent linkage of 4'-phosphopantetheine (4'-PP) to residue serine-36. We found that the long flexible 4'-PP arm could react chemoselectively with the iodoacetyl group introduced on solid supports with high efficiency under mild conditions. Based on this finding, we developed site-selective immobilisation of proteins via the active holo-ACP fusion tag, independently of the physicochemical properties of the protein of interest. Furthermore, the molecular ratios of co-immobilised proteins can be manipulated because the tethering process is predominantly directed by the molar concentrations of diverse holo-ACP fusions during co-immobilisation. Conveniently tuning the molecular ratios of co-immobilised proteins allows their cooperation, leading to a highly productive multi-protein co-immobilisation system. Kinetic studies of enzymes demonstrated that α-amylase (Amy) and methyl parathion hydrolase (MPH) immobilised via active tag holo-ACP had higher catalytic efficiency (k/Km) in comparison with their corresponding counterparts immobilised via the sulfhydryl groups (-SH) of these proteins. The immobilised holo-ACP-Amy also presented higher thermostability compared with free Amy. The enhanced α-amylase thermostability upon immobilisation via holo-ACP renders it more suitable for industrial application.
Topics: Kinetics; Pantetheine; Acyl Carrier Protein; Escherichia coli; alpha-Amylases; Immobilized Proteins
PubMed: 36307012
DOI: 10.1016/j.nbt.2022.10.004 -
Frontiers in Toxicology 2022Organophosphorus pesticides (OPs) are a chemically diverse class of commonly used insecticides. Epidemiological studies suggest that low dose chronic prenatal and infant...
Organophosphorus pesticides (OPs) are a chemically diverse class of commonly used insecticides. Epidemiological studies suggest that low dose chronic prenatal and infant exposures can lead to life-long neurological damage and behavioral disorders. While inhibition of acetylcholinesterase (AChE) is the shared mechanism of acute OP neurotoxicity, OP-induced developmental neurotoxicity (DNT) can occur independently and/or in the absence of significant AChE inhibition, implying that OPs affect alternative targets. Moreover, different OPs can cause different adverse outcomes, suggesting that different OPs act through different mechanisms. These findings emphasize the importance of comparative studies of OP toxicity. Freshwater planarians are an invertebrate system that uniquely allows for automated, rapid and inexpensive testing of adult and developing organisms in parallel to differentiate neurotoxicity from DNT. Effects found only in regenerating planarians would be indicative of DNT, whereas shared effects may represent neurotoxicity. We leverage this unique feature of planarians to investigate potential differential effects of OPs on the adult and developing brain by performing a comparative screen to test 7 OPs (acephate, chlorpyrifos, dichlorvos, diazinon, malathion, parathion and profenofos) across 10 concentrations in quarter-log steps. Neurotoxicity was evaluated using a wide range of quantitative morphological and behavioral readouts. AChE activity was measured using an Ellman assay. The toxicological profiles of the 7 OPs differed across the OPs and between adult and regenerating planarians. Toxicological profiles were not correlated with levels of AChE inhibition. Twenty-two "mechanistic control compounds" known to target pathways suggested in the literature to be affected by OPs (cholinergic neurotransmission, serotonin neurotransmission, endocannabinoid system, cytoskeleton, adenyl cyclase and oxidative stress) and 2 negative controls were also screened. When compared with the mechanistic control compounds, the phenotypic profiles of the different OPs separated into distinct clusters. The phenotypic profiles of adult vs. regenerating planarians exposed to the OPs clustered differently, suggesting some developmental-specific mechanisms. These results further support findings in other systems that OPs cause different adverse outcomes in the (developing) brain and build the foundation for future comparative studies focused on delineating the mechanisms of OP neurotoxicity in planarians.
PubMed: 36267428
DOI: 10.3389/ftox.2022.948455 -
Global Challenges (Hoboken, NJ) Sep 2022Glyphosate is a globally applied herbicide yet it has been relatively undetectable in-field samples outside of gold-standard techniques. Its presumed nontoxicity toward...
Glyphosate is a globally applied herbicide yet it has been relatively undetectable in-field samples outside of gold-standard techniques. Its presumed nontoxicity toward humans has been contested by the International Agency for Research on Cancer, while it has been detected in farmers' urine, surface waters and crop residues. Rapid, on-site detection of glyphosate is hindered by lack of field-deployable and easy-to-use sensors that circumvent sample transportation to limited laboratories that possess the equipment needed for detection. Herein, the flavoenzyme, glycine oxidase, immobilized on platinum-decorated laser-induced graphene (LIG) is used for selective detection of glyphosate as it is a substrate for GlyOx. The LIG platform provides a scaffold for enzyme attachment while maintaining the electronic and surface properties of graphene. The sensor exhibits a linear range of 10-260 m, detection limit of 3.03 m, and sensitivity of 0.991 nA m . The sensor shows minimal interference from the commonly used herbicides and insecticides: atrazine, 2,4-dichlorophenoxyacetic acid, dicamba, parathion-methyl, paraoxon-methyl, malathion, chlorpyrifos, thiamethoxam, clothianidin, and imidacloprid. Sensor function is further tested in complex river water and crop residue fluids, which validate this platform as a scalable, direct-write, and selective method of glyphosate detection for herbicide mapping and food analysis.
PubMed: 36176938
DOI: 10.1002/gch2.202200057 -
Environment International Nov 2022Exposure of pet dogs and cats to pesticides used in and around homes (e.g., lawns and gardens) is a significant health concern. Furthermore, some pesticides are directly...
Exposure of pet dogs and cats to pesticides used in and around homes (e.g., lawns and gardens) is a significant health concern. Furthermore, some pesticides are directly used on dogs and cats for flea, lice, and tick control. Despite this, little is known regarding the extent of pesticide exposure in pets. In this study, we determined the concentrations of 30 biomarkers of pesticide exposure in urine collected from dogs and cats in New York State, USA: 6 dialkylphosphate (DAP) metabolites of organophosphates (OPs); 14 neonicotinoids (neonics); 3 specific metabolites of OPs; 5 pyrethroids (PYRs); and 2 phenoxy acids (PAs). The sum median concentrations of these 30 pesticide biomarkers (ΣPesticides) in dog and cat urine were 35.2 and 38.1 ng/mL, respectively. Neonics were the most prevalent in dogs (accounting for 43% of the total concentrations), followed by DAPs (17%), PYRs (16%), OPs (13%), and PAs (∼10%). In cat urine, neonics alone accounted for 83% of the total concentrations. Elevated concentrations of imidacloprid were found in the urine of certain dogs (max: 115 ng/mL) and cats (max: 1090 ng/mL). Some pesticides showed gender- and sampling location- related differences in urinary concentrations. We calculated daily exposure doses of pesticides from the measured urinary concentrations through a reverse dosimetry approach. The estimated daily intakes (DIs) of chlorpyrifos, diazinon, and cypermethrin were above the chronic reference doses (cRfDs) in 22, 76, and 5%, respectively, of dogs. The DIs of chlorpyrifos, parathion, diazinon, and imidacloprid were above the cRfDs in 33, 14, 100, and 29%, respectively, of cats. This study thus provides evidence that pet dogs and cats are exposed to certain pesticides at levels that warrant immediate attention.
Topics: Animals; Biomarkers; Cat Diseases; Cats; Chlorpyrifos; Diazinon; Dog Diseases; Dogs; Environmental Exposure; Neonicotinoids; New York; Nitro Compounds; Parathion; Pesticides; Pyrethrins; United States
PubMed: 36155914
DOI: 10.1016/j.envint.2022.107526