Applications of Microbial Organophosphate-Degrading Enzymes to Detoxification of Organophosphorous Compounds for Medical Countermeasures against Poisoning and Environmental Remediation.

Mining of organophosphorous (OPs)-degrading bacterial enzymes in collections of known bacterial strains and in natural biotopes are important research fields that lead to the isolation of novel OP-degrading enzymes. Then, implementation of strategies and methods of protein engineering and nanobiotechnology allow large-scale production of enzymes, displaying improved catalytic properties for medical uses and protection of the environment. For medical applications, the enzyme formulations must be stable in the bloodstream and upon storage and not susceptible to induce iatrogenic effects. This, in particular, includes the nanoencapsulation of bioscavengers of bacterial origin. In the application field of bioremediation, these enzymes play a crucial role in environmental cleanup by initiating the degradation of OPs, such as pesticides, in contaminated environments. In microbial cell configuration, these enzymes can break down chemical bonds of OPs and usually convert them into less toxic metabolites through a biotransformation process or contribute to their complete mineralization. In their purified state, they exhibit higher pollutant degradation efficiencies and the ability to operate under different environmental conditions. Thus, this review provides a clear overview of the current knowledge about applications of OP-reacting enzymes. It presents research works focusing on the use of these enzymes in various bioremediation strategies to mitigate environmental pollution and in medicine as alternative therapeutic means against OP poisoning.

Detoxification of V-Nerve Agents Assisted by a Microperoxidase: New Pathway Revealed by the Use of a Relevant VX Simulant.

The biocatalyzed oxidative detoxification of the V-series simulant PhX, by mean of the microperoxidase AcMP11, affords the corresponding phosphonothioate as the prominent product instead of the classical P-S and P-O bond cleavage. While PhX is structurally very close to the live agent VX (the methyl group is replaced by a phenyl), assessment with other surrogates missing the nucleophilic amino function displayed more resistance under the same conditions with no phosphonothioate observed. These encouraging results highlight 1) the efficacy of AcMP11 microperoxidase to efficiently detoxify V-series organophosphorus nerve agents (OPNA), and 2) the necessity to use representative alkyl or aryl phosphonothioates simulants such as PhX bearing the appropriate side chain as well as the P-O and P-S cleavable bond to mimic accurately the V-series OPNA to prevent false positive or false negative results.

Pralidoxime Is no Longer Fit for Purpose as an Antidote to Organophosphate Poisoning in the United Kingdom.

Pralidoxime is the only oxime antidote to organophosphate poisoning stocked in the United Kingdom, produced by rational drug design in the 1950s. Typically, it is used alongside atropine, to reverse the effects of acetylcholinesterase inhibition. However, its efficacy has been questioned by recent meta-analyses of use treating attempted suicides in less economically developed countries, where organophosphate poisoning is more common. This policy analysis assesses the likely efficacy of pralidoxime in the United Kingdom, in scenarios largely different from those evaluated in meta-analyses. In all scenarios, the UK delay in antidote administration poses a major problem, as pralidoxime acts in a time-critical reactivation mechanism before "ageing" of acetylcholinesterase occurs. Additionally, changes in the organophosphates used today versus those pralidoxime was rationally designed to reverse, have reduced efficacy since the 1950s. Finally, the current dosage regimen may be insufficient. Therefore, one must re-evaluate our preparedness and approach to organophosphate poisoning in the United Kingdom.

[Interaction of DNA Methyltransferase Dnmt3a with Phosphorus Analogs of S-Adenosylmethionine and S-Adenosylhomocysteine].

Enzymatic methyltransferase reactions are of crucial importance for cell metabolism. S-Adenosyl-L-methionine (AdoMet) is a main donor of the methyl group. DNA, RNA, proteins, and low-molecular-weight compounds are substrates of methyltransferases. In mammals, DNA methyltransferase Dnmt3a de novo methylates the C5 position of cytosine residues in CpG sequences in DNA. The methylation pattern is one of the factors that determine the epigenetic regulation of gene expression. Here, interactions with the catalytic domain of Dnmt3a was for the first time studied for phosphonous and phosphonic analogs of AdoMet and S-adenosyl-L-homocysteine (AdoHcy), in which the carboxyl group was substituted for respective phosphorus-containing group. These AdoMet analogs were shown to be substrates of Dnmt3a, and the methylation efficiency was only halved as compared with that of natural AdoMet. Both phosphorus-containing analogs of AdoHcy, which is a natural methyltransferase inhibitor, showed similar inhibitory activities toward Dnmt3a and were approximately four times less active than AdoHcy. The finding that the phosphonous and phosphonic analogs are similar in activity was quite unexpected because the geometry and charge of their phosphorus-containing groups differ substantially. The phosphorus-containing analogs of AdoMet and AdoHcy are discussed as promising tools for investigation of methyltransferases.

Accumulation and release of organic pollutants by conventional and biodegradable microplastics in the marine environment.

The issue of microplastic (MP) litter in the aquatic environment and its capability of accumulating and/or releasing pollutants has been brought to light in recent years. Biodegradable plastics have been proposed as one of the different solutions to decrease environmental input of discarded plastics; however, their ability to accumulate and release pollutants once in the marine environment has not been assessed yet. In this study, we compare the accumulation and the release of a wide range of compounds by biodegradable (polyhydroxyalkanoates (PHA) and polybutylene succinate (PBS)) and conventional (polyethylene (PE)) MPs following exposure to natural seawater for 64 days. We quantified polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organophosphorus flame retardants (PFRs), phthalates, and alternative plasticizers in MPs, before and after exposure. Results indicated that PBS- and PHA-MPs accumulated the largest amount of PAHs and PFRs, respectively. Leaching of PFRs and plasticizers was observed for all polymers and was approximately twofold greater for PE- when compared to PBS- and PHA-MPs. Overall, our study suggests that biodegradable MPs may release less additives and accumulate a larger amount of contaminants from seawater compared to conventional ones: these findings may have implications on the risk assessment of biodegradable polymers for marine biota; and on potential widespread adoption of these types of plastics.

Functionalized oxacalix[4]arene based fluorescent probes for the detection of organophosphorus nerve agent simulants.

Despite the largely tranquil environment in which humans live, a chemical terrorism attack is still a public safety problem, for which the capacity to quickly and accurately detect chemical warfare agents (CWAs) constitute a significant barrier. In this study, a straightforward fluorescent probe based on dinitrophenylhydrazine has been synthesised. It exhibits great selectivity and sensitivity for the nerve agent mimicking dimethyl chlorophosphate (DMCP) in the MeOH solution. Dinitrophenylhydrazine-oxacalix[4]arene (DPHOC), a 2,4-dinitrophenylhydrazine (2,4-DNPH) derivative, was synthesised and characterized with NMR and ESI-MS. Photophysical behavior, specially spectrofluorometric analysis was introduced to investigate the sensing phenomena of DPHOC toward dimethyl chlorophosphate (DMCP). The LOD of DPHOC toward DMCP was determined to be 2.1 µM, with a linear range from 5 to 50 µM (R2 = 0.99933). Moreover, DPHOC has been proven to be a promising probe toward the real time detection of DMCP.

Breast carcinogenesis induced by organophosphorous pesticides.

Breast cancer is a major health threat to women worldwide and the leading cause of cancer-related death. The use of organophosphorous pesticides has increased in agricultural environments and urban settings, and there is evidence that estrogen may increase breast cancer risk in women. The mammary gland is an excellent model for examining its susceptibility to different carcinogenic agents due to its high cell proliferation capabilities associated with the topography of the mammary parenchyma and specific stages of gland development. Several experimental cellular models are presented here, in which the animals were exposed to chemical compounds such as pesticides, and endogenous substances such as estrogens that exert a significant effect on normal breast cell processes at different levels. Such models were developed by the effect of malathion, parathion, and eserine, influenced by estrogen demonstrating features of cancer initiation in vivo as tumor formation in rodents; and in vitro in the immortalized normal breast cell line MCF-10F, that when transformed showed signs of carcinogenesis such as increased cell proliferation, anchorage independence, invasive capabilities, modulation of receptors and genomic instability. The role of acetylcholine was also demonstrated in the MCF-10F, suggesting a role not only as a neurotransmitter but also with other functions, such as induction of cell proliferation, playing an important role in cancer. Of note, this is a unique experimental approach that identifies mechanistic signs that link organophosphorous pesticides with breast carcinogenesis.

Residue analysis of selected organophosphorus and organochlorine pesticides in commercial tomato fruits by gas chromatography mass spectrometry.

In this study, analysis of some selected organophosphorus and organochlorine pesticides was carried out in tomato samples collected from the markets of Mettu town, Ilu Aba Bora Zone, Oromia, Ethiopia. The quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was used for the extraction of collected samples using acetonitrile with 1% acetic acid, anhydrous magnesium sulfate, and anhydrous sodium acetate, followed by dispersive solid-phase extraction (d-SPE). Chromatographic separation and quantitative determination of the pesticides were performed by gas chromatography equipped with a mass spectrometer. The calibration curves for each analyte constructed in tomato samples were linear in the concentration range of 2-200 µg/kg with R2 > 0.99 and the LODs and LOQs of the method were in the range of 0.01-0.04 µg/kg and 0.04-0.13 µg/kg, respectively. The recovery and precision study results were within acceptable standard guidelines. Of the fourteen pesticides tested, chlordane, hexachlorobenzene, 4, 4'-DDE, 4, 4'-DDD, 4, 4'- DDT, and profenofos were detected at 0.15, 0.09, 0.17, 0.032, 1.24 and 0.062 µg/kg, respectively. Despite the concentrations of the detected pesticides being lower than the maximum residue limit recommended by FAO/WHO, the presence of these toxic chemicals in tomatoes indicates product contamination and requires extensive further investigation with the inclusion of other pesticides.

Pesticide exposure and asthma morbidity in children residing in urban, multi-family housing.

BACKGROUND: Children are potentially more susceptible to the adverse effects of pesticides due to more sensitive organ systems and lower capacity to metabolize and eliminate chemicals compared to adults. The health risks are particularly concerning children with asthma, living in low-income neighborhoods in multi-family housing because of their impaired respiratory health, and factors associated with low-income, multi-family environments. OBJECTIVE: To assess the association between pesticide exposure and asthma morbidity among children 7-12 years residing in low-income, multi-family housing. METHODS: The concentrations of seven urinary pesticide biomarkers: 3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-4-methyl-6-hydroxypyrimidine, para-nitrophenol (PNP), 3-phenoxybenzoic acid (3-PBA), 4-fluoro-3-phenoxybenzoic acid, trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid, and 2,4-dichlorophenoxyacetic acid (2,4-D) were measured. Children (n = 162) were followed for one year with three measures of pesticides biomarkers. Associations between individual biomarkers and asthma attack, asthma related health care utilization, and fraction of exhaled nitric oxide (FeNO), adjusting for demographic and household factors were examined with Generalized Estimating Equations (GEE). Weighted Quantile Sum (WQS) regression was used to examine the effect of pesticide mixture on asthma attacks and asthma-related health care utilization (HCU). RESULTS: In adjusted GEE models, positive non-significant associations were found between PNP and HCU (adjusted Odds Ratio(aOR):2.05 95% CI:0.76-5.52) and null associations for 3-PBA and HCU (aOR:1.07 95% CI: 0.88-1.29). Higher concentrations of PNP and 2,4-D were associated with significantly lower FeNO levels (PNP: -17.4%; 2,4-D:-19.74%). The mixture was positively associated with HCU in unadjusted (OR: 1.56 97.5% CI: 1.08-2.27) but not significant in adjusted models (aOR: 1.40 97.5% CI: .86-2.29). The non-specific pyrethroid biomarker 3-PBA at baseline contributed the greatest weight to the index (45%). SIGNIFICANCE: There were non-significant associations between pesticide biomarkers and respiratory outcomes in children with asthma. There was a suggestive association between urinary pesticide biomarkers and HCU. Further studies with larger sample sizes could help to confirm these findings. IMPACT STATEMENT: Pesticide exposure among children in the urban environment is ubiquitous and there is a dearth of information on the impact of low-level chronic exposure in vulnerable populations. This study suggested that pesticide exposure at concentrations below the national average may not affect asthma morbidity in children. However, different biomarkers of pesticides showed different effects, but the mixture suggested increasing pesticide exposure results in asthma related HCU. The results may show that children with asthma may be at risk for negative health outcomes due to pesticides and the need to further examine this relationship.

The association of prenatal phthalates, organophosphorous pesticides, and organophosphate esters with early child language ability in Norway.

BACKGROUND: Prenatal exposure to phthalates, organophosphate esters, and organophosphorous pesticides have been associated with neurodevelopmental deficits including language ability, however, few studies consider the effect of exposure mixtures and the potential longitudinal detriments over time. OBJECTIVE: This study examines the influence of prenatal exposure to phthalates, organophosphate esters, and organophosphorous pesticides, on children's language ability from toddlerhood to the preschool period. METHODS: This study includes 299 mother-child dyads from Norway in the Norwegian Mother, Father and Child Cohort Study (MoBa). Prenatal exposure to chemicals were assessed at 17 weeks' gestation, and child language skills were assessed at 18 months using the Ages and Stages Questionnaire communication subscale and at preschool age using the Child Development Inventory. We ran two structural equation models to examine the simultaneous influences of chemical exposures on parent-reported and teacher-reported child language ability. RESULTS: Prenatal organophosphorous pesticides were negatively associated with preschool language ability through language ability at 18 months. Additionally, there was a negative association between low molecular weight phthalates and teacher-reported preschool language ability. There was no effect of prenatal organophosphate esters on child language ability at either 18 months or preschool age. CONCLUSIONS: This study adds to the literature on prenatal exposure to chemicals and neurodevelopment and highlights the importance of developmental pathways in early childhood.

Evaluation of paraoxonase I and hemoglobin levels in farmers and agricultural workers in relation to organophosphorus and carbamate levels in their blood and urine samples: A cross sectional study.

Background: Pesticides are chemicals that have become common household products in developing countries. The purpose of pesticides is to manage agricultural work. The majority of pesticides for indoor and agricultural use are carbamate and organophosphorus. Toxicity is caused due to excess and improper use or disposal of these chemical agents. Slow exposure to pesticides causes chronic poisoning whereas rapid exposure causes acute poisoning. The paraoxonase I (PON 1) enzyme has a role in detoxifying some of the oxon derivatives which thereby inhibit acetylcholinesterase and butyrylcholinesterase. Methods: This study analyzed farmers who were exposed intermittently to organophosphorus and carbamates pesticides during farming for more than five years. Serum paraoxonase I was evaluated by colorimetry method, and hemoglobin levels were evaluated using portable Fresenius Kabi haemoglobinometer. Results: The study showed that the pesticides were found in the blood and urine samples of farmers and there was an alteration of paraoxonase I and hemoglobin levels in them due to the exposure of pesticides in large quantities over some time. The present study showed around 81% of the participants who were intermittently exposed to pesticides for more than five years were detected with pesticide toxicity. The paraoxonase I level was altered in farmers who were positive for organophosphorus and carbamate pesticides. The hemoglobin level did not show much variation among the farmers exposed to pesticides. This may be due to the lifestyle of the subjects, climatic variations and also their eating habits. Conclusions: The study suggested that there was alteration in the levels of PON1 and hemoglobin in farmers and agricultural workers with positive organophosphorus and carbamates in their blood and urine samples. As our study was done without quantifying the amount of pesticides, further studies can be done by quantifying the pesticide level and comparing it with the paraoxonase I level.

Intermediate syndrome following organophosphate poisoning: A case report in a low resource and poor socio-economic setting.

Intermediate syndrome with respiratory failure is a serious complication that can be fatal as in our case of a 24-year-old-man who developed intermediate syndrome requiring intubation and respiratory support. Furthermore, the patient's socio-economic situation significantly impacts the illness's progress and prognosis.

Recovery of Metals from Electronic Waste-Printed Circuit Boards by Ionic Liquids, DESs and Organophosphorous-Based Acid Extraction.

The extraction of metals from waste printed circuit boards (WPCBs) with ionic liquids (ILs), Deep Eutectic Solvents (DESs) and organophosphorous-based acid (Cyanex 272) has been presented. The study was undertaken to assess the effectiveness of the application of the new leaching liquids, and the new method of extraction of metals from the leachate and the solid phase with or without the leaching process. Solvent extraction from the liquid leachate phase has been studied in detail with popular ILs, such as tetraoctylphosphonium bromide, {[P8,8,8,8][Br] and tributyltetradecylphosphonium chloride, [P4,4,4,14][Cl] using Aqueous Biphasic Systems (ABS) method. Trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate, [P6,6,6,14][Cyanex272], ([P6,6,6,14][BTMPP]), trihexyltetradecylphosphonium thiocyanate, [P6,6,6,14][SCN], methyltrioctylammonium chloride (Aliquat 336), as well as bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) were also used in the extraction of metals from the leachate. Two DESs (1) {choline chloride + lactic acid, 1:2} and (2) {choline chloride + malonic acid, 1:1} were used in the extraction of metals from the solid phase. The extraction behavior of metals with DESs was compared with that performed with three new bi-functional ILs: didecyldimethylammonium salicylate, [N10,10,1,1][Sal], didecyldimethylammonium bis(2-ethylhexyl) phosphate, [N10,10,1,1][D2EHPA], and didecyldimethylammonium bis(2,4,4-trimethylpentyl) phosphinate, [N10,10,1,1][Cyanex272]. The [P6,6,6,14][Cyanex272]/toluene and (Cyanex 272 + diethyl phosphite ester) mixtures exhibited a high extraction efficiency of about 50-90% for different metal ions from the leachate. High extraction efficiency of about 90-100 wt% with the ABS method using the mixture {[P8,8,8,8][Br], or [P4,4,4,14][Cl] + NaCl + H2O2 + post-leaching liquid phase} was obtained. The DES 2 revealed the efficiency of copper extraction, ECu = 15.8 wt% and silver, EAg = 20.1 wt% at pH = 5 from the solid phase after the thermal pre-treatment and acid leaching. The solid phase extraction efficiency after thermal pre-treatment only was (ECu = 9.6 wt% and EAg = 14.2 wt%). The use of new bi-functional ILs did not improve the efficiency of the extraction of metal ions from the solid phase. Process factors such as solvent concentration, extraction additives, stripping and leaching methods, temperature, pH and liquid/solid as well as organic/water ratios were under control. For all the systems, the selectivity and distribution ratios were described. The proposed extraction processes can represent alternative paths in new technologies for recovering metals from electronic secondary waste.

Nanostructured polyaniline SPME fiber coating for chemical warfare agents analysis.

Nanostructured polyaniline (PANI) was electrochemically obtained as a fiber coating of solid-phase microextraction (SPME) and then used in the analysis of selected organoarsenic and organophosphorus compounds in soil samples. Also, comparative studies of the obtained PANI fibers with seven commercially available fibers for varying miscellaneous polarity, and various absorption and/or adsorption natures, were carried out. Quantitative analysis of environmental samples was performed using a gas chromatograph coupled with a tandem mass spectrometer. During the analysis of organophosphorus compounds, the PANI fiber showed at least 20% greater sorption efficiency than any commercially available fiber, whereas, in the case of organoarsenic compounds, the sorption efficiency of the PANI fiber increased with the expansion in the number of phenyl rings in the molecule. The PANI coating material was characterised by N2 adsorption-desorption, scanning electron microscopy, infrared spectroscopy and thermogravimetric analysis. SEM imaging confirmed a nanostructured form of PANI. The repeatability for one fiber (n = 7), expressed as the relative standard deviation ranges from 3.2% to 4.4% depending on the kind of tested chemical compound. The reproducibility (calculated as relative standard deviation of the 9 prepared fibers) was not greater than 7.2% Under the optimized conditions, the proposed method was linear over approximately 4 orders for organophosphorus compounds (0.02-100 ng g-1) and 5 orders for organoarsenic compounds (0.12-5000 ng g-1) of magnitude for the tested compounds, with linear determination coefficients (R2) greater than 0.972, and the limit of detection for the home-made PANI fiber was relatively low (0.006-0.45 ng g-1). In comparison with all commercially available SPME fibers, the new PANI fiber was more selective for the tested aromatic and organophosphorus compounds and easily as well as inexpensively prepared. The resulting stationary phase allowed for quantitative analysis of selected organophosphorus and organoarsenic compounds from the group of warfare agents.

Critical review of analytical methods for the determination of flame retardants in human matrices.

Human biomonitoring is a powerful approach in assessing exposure to environmental pollutants. Flame retardants (FRs) are of particular concern due to their wide distribution in the environment and adverse health effects. This article reviews studies published in 2009-2020 on the chemical analysis of FRs in a variety of human samples and discusses the characteristics of the analytical methods applied to different FR biomarkers of exposure, including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), novel halogenated flame retardants (NHFRs), bromophenols, incl. tetrabromobisphenol A (TBBPA), and organophosphorous flame retardants (PFRs). Among the extraction techniques, liquid-liquid extraction (LLE) and solid phase extraction (SPE) were used most frequently due to the good efficiencies in the isolation of the majority of the FR biomarkers, but with challenges for highly lipophilic FRs. Gas chromatography-mass spectrometry (GC-MS) is mainly applied in the instrumental analysis of PBDEs and most NHFRs, with recent inclusions of GC-MS/MS and high resolution MS techniques. Liquid chromatography-MS/MS is mainly applied to HBCD, bromophenols, incl. TBBPA, and PFRs (including metabolites), however, GC-based analysis following derivatization has also been used for phenolic compounds and PFR metabolites. Developments are noticed towards more universal analytical methods, which enable widening method scopes in the human biomonitoring of FRs. Challenges exist with regard to sensitivity required for the low concentrations of FRs in the general population and limited sample material for some human matrices. A strong focus on quality assurance/quality control (QA/QC) measures is required in the analysis of FR biomarkers in human samples, related to their variety of physical-chemical properties, low levels in most human samples and the risk of contamination.

Synthesis, Molecular Docking, BSA, and In Vitro Reactivation Study of Imidazopyridine Oximes Against Paraoxon Inhibited Acetylcholinesterase.

AIM: To synthesize and evaluate the fused heterocyclic imidazo[1,2-a]pyridine based oxime as a reactivator against paraoxon inhibited acetylcholinesterase. BACKGROUND: Organophosphorus compounds (OPs) include parathion, malathion, chlorpyrifos, monocrotophos, and diazinon, which are commonly used in agriculture for enhancing agricultural productivity via killing crop-damaging pests. However, people may get exposed to OPs pesticides unintentionally/intentionally via ingestion, inhalation, or dermal. The current treatment regimen includes reactivator such as mono or bis-pyridinium oximes along with anticholinergic and anticonvulsant drugs that are recommended for the treatment of OP poisoning. Unfortunately, the drawback of the existing reactivator is the permanent charge present on the pyridinium, making them inefficient to cross the blood-brain barrier (BBB) and reactivate OP-inhibited central nervous system (CNS) acetylcholinesterase. Therefore, there is a need of a reactivator that could cross the BBB and reactivate the OP inhibited acetylcholinesterase. OBJECTIVE: The objectives of the study were synthesis, molecular docking, BSA binding, and in-vitro estimation of oximes of various substituted imidazo [1,2-a]pyridine against paraoxon inhibited acetylcholinesterase. METHODS: The reactivators were synthesized in three steps and characterized using various spectroscopic techniques. The molecular docking study was performed on 2WHP and 3ZLV PDB using the Glide-XP software. The acid dissociation constant (pKa) of oximes was calculated experimentally, and the drug-likeness properties of the oximes were calculated in silico using Molinspiration and Swiss ADME software. The binding of oximes with bovine serum albumin (BSA) was also investigated using a Fluorescence spectrophotometer. The reactivation potential of the oximes was determined by in vitro enzymatic assay. RESULTS: The In-silico study inferred that the synthesized molecules fulfilled the parameters required for a successful CNS drug candidate. Furthermore, in-vitro enzymatic assay indicated reasonable reactivation potential of the oximes against paraoxon-inhibited AChE. The binding of oximes with bovine serum albumin (BSA) revealed that there was a static quenching of intrinsic fluorescence of BSA by the oxime. The binding constant value and number of binding sites were found to be 0.24 x 104 mol-1 and 1, respectively. CONCLUSION: The results of the study concluded that this scaffold could be used for further designing of more efficient uncharged reactivators.

Biodegradation pathway of the organophosphate pesticides chlorpyrifos, methyl parathion and profenofos by the marine-derived fungus Aspergillus sydowii CBMAI 935 and its potential for methylation reactions of phenolic compounds.

The indiscriminate use of organophosphate pesticides causes serious environmental and human health problems. This study aims the biodegradation of chlorpyrifos, methyl parathion and profenofos with the proposal of new biodegradation pathways employing marine-derived fungi as biocatalysts. Firstly, a growth screening was carried out with seven fungi strains and Aspergillus sydowii CBMAI 935 was selected. For chlorpyrifos, 32% biodegradation was observed and the metabolites tetraethyl dithiodiphosphate, 3,5,6-trichloropyridin-2-ol, 2,3,5-trichloro-6-methoxypyridine, and 3,5,6-trichloro-1-methylpyridin-2(1H)-one were identified. Whereas 80% methyl parathion was biodegraded with the identification of isoparathion, methyl paraoxon, trimethyl phosphate, O,O,O-trimethyl phosphorothioate, O,O,S-trimethyl phosphorothioate, 1-methoxy-4-nitrobenzene, and 4-nitrophenol. For profenofos, 52% biodegradation was determined and the identified metabolites were 4-bromo-2-chlorophenol, 4-bromo-2-chloro-1-methoxybenzene and O,O-diethyl S-propylphosphorothioate. Moreover, A. sydowii CBMAI 935 methylated different phenolic substrates (phenol, 2-chlorophenol, 6-chloropyridin-3-ol, and pentachlorophenol). Therefore, the knowledge about the fate of these compounds in the sea was expanded, and the marine-derived fungus A. sydowii CBMAI 935 showed potential for biotransformation reactions.

Development and validation of an analysis method for pesticide residues by gas chromatography-tandem mass spectrometry in Daikenchuto.

Daikenchuto (DKT) is one of the most widely used "Kampo" in Japan as a representative of herbal medicine. Because DKT is made from a natural product like food, it requires the management of pesticides; therefore, an analysis of residual pesticides in Kampo is required. The World Health Organization (WHO) indicates that pesticide residue analysis by the U.S. Pharmacopeia (USP) is required. USP defines 107 compounds containing organochlorine pesticides and organophosphorus pesticides and their metabolites, which have a high residual risk. Accordingly, to guarantee the safety of herbal medicines according to global standards is a very important issue. In this study, we developed an analytical method for 91 compounds, which are listed in USP, using DKT as the subject. The method could extract pesticides from DKT with acetone, elute pesticides with acetonitrile using a SepPak C18 column (5 g) and with ethyl acetate using a DSC-NH2 column (2 g), and perform simultaneous analyses by gas chromatography-tandem mass spectrometry (GC-MS/MS). This method, which could quantify 88 compounds, was validated according to USP. A pesticide residue analysis method that meets USP requirements enables the analysis of pesticide residues with a high residue risk and contributes to improving the safety of "Kampo" and other herbal medicines.

Ensayo estandarizado (ISO 17512) de comportamiento de evitación de suelos contaminados. Efecto del pesticida dimetoato sobre la lombriz de tierra Aporrectodea caliginosa / Standardized avoidance test (ISO 17512) for contaminated soils. Effect of the pesticide dimethoate on the earthworm Aporrectodea caliginosa

La creciente preocupación por el bienestar animal ha propiciado el rechazo por parte de la sociedad a la utilización de animales en experimentación. Por este motivo, actualmente se están desarrollando métodos alternativos que cumplan con el principio de las 3Rs (reemplazar, reutilizar y refinar). Muchos de estos métodos se basan en la utilización de organismos inferiores, como las lombrices de tierra. El presente estudio desarrolla el ensayo estandarizado de la Organización Internacional de Normalización (ISO) 17512-1:2008, en el que se evalúa la toxicidad producida por el plaguicida organofosforado dimetoato en el suelo, utilizando la capacidad de repulsión o evitación que presentan las lombrices de tierra pertenecientes a la especie Aporrectodea caliginosa. Las concentraciones seleccionadas han sido 0,06, 0,3 y 1,5 mg/kg de suelo, ensayada cada una de ellas por triplicado, empleando 10 lombrices por cada réplica. Los resultados reflejan la capacidad de las lombrices de tierra de la especie Aporrectodea caliginosa para evitar suelos contaminados con el formulado comercial de dimetoato. Por otra parte, se confirma la tendencia de las lombrices a evitar el suelo contaminado a medida que aumenta la concentración de plaguicida ensayada, con significación estadística a la dosis más alta empleada (1,5 mg/kg). (AU)

The increasing concern about animal wellness has induced the repulse of society to the use of animals in research. For this reason, alternative methods which comply with the 3Rs principle (Replace, Reuse and Refine) are currently being developed. Many of these methods are based on the use of lower organisms on the evolutionary scale, such as earthworms. The present study develops the standardized test of the International Organization of Standardization (ISO) 17512-1:2008, in which the toxicity produced by the pesticide organophosphate dimethoate in the soil is evaluated, using the capacity of repulsion or avoidance that presents the earthworms Aporrectodea caliginosa. The assayed concentrations were 0.06, 0.3 and 1.5 mg/kg of soil, each one tested in triplicated, using 10 earthworms for each repetition. The results reflect the ability of earthworms of the species Aporrectodea calliginosa to avoid soils contaminated with the commercial formulation of dimethoate. On the other hand, the tendency of worms to avoid contaminated soils is confirmed as the concentration of pesticide increases, with statistical significance at the highest concentration used (1.5 mg/kg). (AU)

Double-side microcantilevers as a key to understand the adsorption mechanisms and kinetics of chemical warfare agents on vertically-aligned TiO2 nanotubes.

Microgravimetric sensor platforms with physico- or chemo-selective interfaces offer promising sensing properties. They are widely used to detect chemical warfare agents (CWAs). However, a comprehensive insight into adsorption mechanisms and interactions between low concentrations of these adsorbates and low-mass adsorbents is still lacking. In this study, we report a complete and detailed analytical method to model the adsorption processes of low traces of vapor-phase DiMethyl MethylPhosphonate (DMMP), a conventional simulant of CWAs, on a double-side nanostructured microcantilever coated with vertically-aligned titanium dioxide nanotubes (TiO2-NTs). We find that the geometrical configuration of NTs plays an important role in the diffusion regimes of molecules during the adsorption. This study shines light on the adsorption and kinetic mechanisms of low-traces DMMP offering opportunities to have a better insight of the adsorption of CWAs on complex nanostructures and to improve microcantilever sensors.