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Environmental Health Perspectives Dec 2002In November 1994 methyl parathion (MP), a restricted agricultural pesticide, was discovered to have been illegally sprayed within hundreds of residences in Lorain...
In November 1994 methyl parathion (MP), a restricted agricultural pesticide, was discovered to have been illegally sprayed within hundreds of residences in Lorain County, Ohio. Surface levels and air concentrations of MP revealed detectable levels of the pesticide 3 years after spraying. Because of the high toxicity of MP (lethal dose to 50% of rats tested [LD50] = 15 mg/kg) and long half-life indoors, risk-based relocation and decontamination criteria were created. Relocation criteria were derived based on levels of p-nitrophenol in urine, a metabolic byproduct of MP exposure. In Ohio, concentrations of MP on surfaces and in the air were also used to trigger relocations. The criteria applied in Ohio underwent refinement as cases of MP misuse were found in Mississippi and then in several other states. The MP investigation (1994-1997) was the largest pesticide misuse case in the nation, ultimately involving the sampling of 9,000 residences and the decontamination of 1,000 properties. This article describes the methodology used for relocation of residents and decontamination of properties having MP.
Topics: Adolescent; Adult; Aged; Air Pollution, Indoor; Child; Child, Preschool; Environmental Monitoring; Environmental Pollution; Female; Housing; Humans; Infant; Infant, Newborn; Insect Control; Insecticides; Male; Methyl Parathion; Middle Aged; Nitrophenols; Ohio; Public Policy; Risk Assessment; Transportation
PubMed: 12634141
DOI: 10.1289/ehp.02110s61061 -
Water Research Dec 2008The photodegradation of parathion in aqueous solutions by UV and UV/H(2)O(2) processes was evaluated. Direct photolysis of parathion both by LP (low pressure) and MP...
The photodegradation of parathion in aqueous solutions by UV and UV/H(2)O(2) processes was evaluated. Direct photolysis of parathion both by LP (low pressure) and MP (medium pressure) lamps at pH 7 was very slow with quantum yields of 6.67+/-0.33x10(-4) and 6.00+/-1.06x10(-4)molE(-1), respectively. Hydrogen peroxide enhanced the photodegradation of parathion through the reaction between UV generated hydroxyl radical and parathion with a second-order reaction rate constant of 9.70+/-0.45x10(9)M(-1)s(-1). An optimum molar ratio between hydrogen peroxide and parathion was determined to be between 300 and 400. Photodegradation of parathion yielded several organic byproducts, of which the paraoxon, 4-nitrophenol, O,O,O-triethyl thiophosphate and O,O-diethyl-methyl thiophosphate were quantified and their occurrence during UV/H(2)O(2) processes were discussed. NO(2)(-), PO(4)(3-), NO(3)(-) and SO(4)(2-) were the major anionic byproducts of parathion photodegradation and their recover ratios were also discussed. A photodegradation scheme suggesting three simultaneous pathways was proposed in the study.
Topics: Hydrogen Peroxide; Insecticides; Oxidation-Reduction; Parathion; Solutions; Ultraviolet Rays; Water
PubMed: 18834610
DOI: 10.1016/j.watres.2008.08.023 -
Nature Communications Jun 2021Enzymes can evolve new catalytic activity when environmental changes present them with novel substrates. Despite this seemingly straightforward relationship, factors...
Enzymes can evolve new catalytic activity when environmental changes present them with novel substrates. Despite this seemingly straightforward relationship, factors other than the direct catalytic target can also impact adaptation. Here, we characterize the catalytic activity of a recently evolved bacterial methyl-parathion hydrolase for all possible combinations of the five functionally relevant mutations under eight different laboratory conditions (in which an alternative divalent metal is supplemented). The resultant adaptive landscapes across this historical evolutionary transition vary in terms of both the number of "fitness peaks" as well as the genotype(s) at which they are found as a result of genotype-by-environment interactions and environment-dependent epistasis. This suggests that adaptive landscapes may be fluid and molecular adaptation is highly contingent not only on obvious factors (such as catalytic targets), but also on less obvious secondary environmental factors that can direct it towards distinct outcomes.
Topics: Adaptation, Physiological; Amino Acid Sequence; Bacteria; Bacterial Proteins; Biocatalysis; Epistasis, Genetic; Evolution, Molecular; Gene-Environment Interaction; Genotype; Hydrolases; Kinetics; Metals; Methyl Parathion; Mutation; Protein Domains; Sequence Homology, Amino Acid
PubMed: 34162839
DOI: 10.1038/s41467-021-23943-x -
Journal of Applied Microbiology Nov 2014Isolation and identification of bacteria capable of degrading organophosphate pesticide quinalphos and elucidation of its biodegradative pathway.
AIMS
Isolation and identification of bacteria capable of degrading organophosphate pesticide quinalphos and elucidation of its biodegradative pathway.
METHODS AND RESULTS
A bacterium capable of degrading organophosphate pesticides was isolated from the pesticide-contaminated soil samples by selective enrichment on quinalphos (QP) as a sole source of carbon and energy. The bacterial strain was identified as Ochrobactrum sp. strain HZM on the basis of its morphological and biochemical characteristics and by phylogenetic analysis based on 16S rRNA gene sequences. The organism utilized various organophosphate pesticides such as quinalphos, profenofos, parathion-methyl and chlorpyrifos as growth substrates. Response surface methodology (RSM) showed optimum conditions for quinalphos degradation at pH 7 and 27°C. 2-Hydroxyquinoxaline and diethyl phosphate were identified as metabolites of quinalphos degradation by HPLC and GC-MS analysis. Cell-free extract of Ochrobactrum sp. strain HZM grown on quinalphos contained the quinalphos hydrolase activity.
CONCLUSIONS
A bacterial strain capable of degrading quinalphos was isolated and identified as Ochrobactrum sp. strain HZM. The organism utilized organophosphate pesticides quinalphos, profenofos, parathion-methyl and chlorpyrifos as carbon sources. The organism degraded quinalphos by hydrolysis to yield 2-hydroxyquinoxaline and diethyl phosphate which were further utilized as carbon sources.
SIGNIFICANCE AND IMPACT OF THE STUDY
The isolated bacterium Ochrobactrum sp. strain HZM was versatile in degrading various organophosphate pesticides. There was complete mineralization of quinalphos by Ochrobactrum sp. This strain could potentially be useful in the bioremediation of soil and water contaminated with toxic organophosphate pesticides.
Topics: Biodegradation, Environmental; Insecticides; Ochrobactrum; Organophosphates; Organothiophosphorus Compounds
PubMed: 25155583
DOI: 10.1111/jam.12627 -
Molecules (Basel, Switzerland) Nov 2023An unprecedented photocatalyst, SmEuSbO, was successfully fabricated in this paper, through a high-temperature solid-state calcination method, which represented its...
An unprecedented photocatalyst, SmEuSbO, was successfully fabricated in this paper, through a high-temperature solid-state calcination method, which represented its first ever synthesis. Additionally, using the solvothermal method, the SmEuSbO/ZnBiSbO heterojunction photocatalyst (SZHP) was fabricated, marking its debut in this study. XRD analysis confirmed that both SmEuSbO and ZnBiSbO exhibited pyrochlore-type crystal structures with a cubic lattice, belonging to the Fd3m space group. The crystal cell parameter was determined to be 10.5682 Å or 10.2943 Å for SmEuSbO or ZnBiSbO, respectively. The band gap width measured for SmEuSbO or ZnBiSbO was 2.73 eV or 2.61 eV, respectively. Under visible light irradiation for 150 min (VLTI-150 min), SZHP exhibited remarkable photocatalytic activity, achieving 100% removal of parathion methyl (PM) concentration and 99.45% removal of total organic carbon (TOC) concentration. The kinetic constant () for PM degradation and visible light illumination treatment was determined to be 0.0206 min, with a similar constant of 0.0202 min observed for TOC degradation. Remarkably, SZHP exhibited superior PM removal rates compared with SmEuSbO, ZnBiSbO, or N-doped TiO photocatalyst, accompanied by removal rates 1.09 times, 1.20 times, or 2.38 times higher, respectively. Furthermore, the study investigated the oxidizing capability of free radicals through the use of trapping agents. The results showed that hydroxyl radicals had the strongest oxidative capability, followed by superoxide anions and holes. These findings provide a solid scientific foundation for future research and development of efficient heterojunction compound catalysts.
PubMed: 38067453
DOI: 10.3390/molecules28237722 -
Beilstein Journal of Nanotechnology 2020Methyl parathion (MP) is one of the most neurotoxic pesticides. An inexpensive and reliable one-step degradation method of MP was achieved through an aqueous suspension...
Methyl parathion (MP) is one of the most neurotoxic pesticides. An inexpensive and reliable one-step degradation method of MP was achieved through an aqueous suspension of copper(I) oxide nanoparticles (NPs). Three different NPs sizes (16, 29 and 45 nm), determined with X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM), were synthesized using a modified Benedict's reagent. H nuclear magnetic resonance (NMR) results show that the hydrolytic degradation of MP leads to the formation of 4-nitrophenol (4-NPh) as the main product. While the P=S bond of MP becomes P=O, confirmed by P NMR. Although CuO is a widely known photocatalyst, the degradation of methyl parathion was associated to the surface basicity of CuO NPs. Indirect evidence for the basicity of CuO NPs was achieved through UV-vis absorption of 4-NPh. Likewise, it was shown that the surface basicity increases with decreasing nanoparticle size. The presence of CuCO on the surface of CuO, identified using X-ray photoelectron spectroscopy (XPS), passivates its surface and consequently diminishes the degradation of MP.
PubMed: 33133999
DOI: 10.3762/bjnano.11.137 -
Journal of Agricultural and Food... Jul 2010The stability, hydrolysis, and uptake of the organophosphates methyl parathion and methyl paraoxon were investigated in SH-SY5Y cells. The stabilities of... (Comparative Study)
Comparative Study
The stability, hydrolysis, and uptake of the organophosphates methyl parathion and methyl paraoxon were investigated in SH-SY5Y cells. The stabilities of ((14)CH(3)O)(2)-methyl parathion ((14)C-MPS) and ((14)CH(3)O)(2)-methyl paraoxon ((14)C-MPO) at 1 microM in culture media had similar half-lives of 91.7 and 101.9 h, respectively. However, 100 microM MPO caused >95% cytotoxicity at 24 h, whereas 100 microM MPS caused 4-5% cytotoxicity at 24 h ( approximately 60% cytotoxicity at 48 h). Greater radioactivity was detected inside cells treated with MPO as compared to MPS, although >80% of the total MPO uptake was primarily dimethyl phosphate (DMP). Maximum uptake was reached after 48 h of (14)C-MPS or (14)C-MPO exposure with total uptakes of 1.19 and 1.76 nM/10(6) cells for MPS and MPO, respectively. The amounts of MPS and MPO detected in the cytosol after 48 h of exposure time were 0.54 and 0.37 nM/10(6) cells, respectively.
Topics: Carbon Radioisotopes; Cell Line, Tumor; Drug Stability; Humans; Insecticides; Isotope Labeling; Methyl Parathion; Paraoxon
PubMed: 20590114
DOI: 10.1021/jf100976v -
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 -
RSC Advances Oct 2021Developing a new functional sensitized structure for improving the inherent property of photoactive materials and selecting an efficient electron donor as a...
A one-step hydrothermal route to fabricate a ZnO nanorod/3D graphene aerogel-sensitized structure with enhanced photoelectrochemistry performance and self-powered photoelectrochemical biosensing of parathion-methyl.
Developing a new functional sensitized structure for improving the inherent property of photoactive materials and selecting an efficient electron donor as a photoelectrochemical (PEC) signal amplification strategy are crucial for achieving excellent PEC biosensors. Herein, we present a facile one-pot hydrothermal strategy for fabricating ZnO nanorod-decorated 3D graphene aerogels (ZnO/GAs). In this nanoarchitecture, GAs act as a new generation enhanced carrier, which can effectively improve the photoactivity of ZnO under visible light by enhancing the interfacial charge transfer. In addition, the as-prepared ZnO/GA nanocomposites exhibited two times higher photocurrent intensity than that of ZnO/graphene. Furthermore, we developed a novel self-powered PEC biosensor based on a ZnO/GAs sensitized structure with the amplification of enzymolysis products for the detection of parathion-methyl. Thiocholin, as a sacrificial electron donor, which is produced from the hydrolysis of acetylthiocholine catalyzed by acetylcholinesterase (AChE), can further significantly improve the photocurrent. Then, the inhibition of AChE activity by parathion-methyl prevented the production of thiocholine, resulting in an obvious decrease in photocurrents. Based on the above results, we fabricated an AChE-based self-powered PEC biosensor for the sensitive and selective determination of parathion-methyl with a linear range of 0.1 ng mL to 0.1 μg mL and a detection limit of 0.03 ng mL (S/N = 3). This PEC biosensing strategy not only gives insights into using GAs as a novel sensibilizer to improve the PEC nature of semiconductors but also provides a promising flexible platform for organophosphorus pesticide detection.
PubMed: 35493183
DOI: 10.1039/d1ra06339a -
Nanomaterials (Basel, Switzerland) Apr 2022Flexible sensors are highly advantageous for integration in portable and wearable devices. In this work, we propose and validate a simple strategy to achieve whole...
Flexible sensors are highly advantageous for integration in portable and wearable devices. In this work, we propose and validate a simple strategy to achieve whole wafer-size flexible SERS substrate via a one-step metal-assisted chemical etching (MACE). A pre-patterning Si wafer allows for PSi structures to form in tens of microns areas, and thus enables easy detachment of PSi film pieces from bulk Si substrates. The morphology, porosity, and pore size of PS films can be precisely controlled by varying the etchant concentration, which shows obvious effects on film integrity and wettability. The cracks and self-peeling of Psi films can be achieved by the drying conditions after MACE, enabling transfer of Psi films from Si wafer to any substrates, while maintaining their original properties and vertical alignment. After coating with a thin layer of silver (Ag), the rigid and flexible PSi films before and after transfer both show obvious surface-enhanced Raman scattering (SERS) effect. Moreover, flexible PSi films SERS substrates have been demonstrated with high sensitivity (down to 2.6 × 10 g/cm) for detection of methyl parathion (MPT) residues on a curved apple surface. Such a method provides us with quick and high throughput fabrication of nanostructured materials for sensing, catalysis, and electro-optical applications.
PubMed: 35407309
DOI: 10.3390/nano12071191