Toxic Organophosphorus Compounds Research Articles

CHOLINESTERASE IMMOBLIZATION FOR LARGE-SCALE PRODUCTION OF HIGH SENSITIVE TEST CARDS FOR RAPID DETECTION OF ORGANOPHOSPHORUS AND CARBAMATE PESTICIDES IN AGRICULTURAL PRODUCTS

A single step test card for field screening of pesticide residues in vegetables based on simultaneous inhibition and reaction of cholinesterase was previously proposed. Here, favorable conditions to immobilize cholinesterase on filter paper for bulk production of this test card were developed. An amount of 28 mL of 6 U/mL cholinesterase solution was sprayed onto a filter paper sheet (210 mm × 297 mm) with speed of 1.5 mL/s. After incubation at -20 ◦C for 60 min, enzyme coated-papers were dried at 60 ◦C for 30 minutes and stacked on indicator and substrate-coated papers. The stack was cut into 10 mm × 10 mm-sized pieces for depositing on metallised polyester film sheets. Then another metallised film which holed 5 mm diameter holes was placed on the paper pieces, and 15 mm × 15 mm reaction windows were made by heat pressing. The developed test card’s detect limit by naked eyes ranged between 0.0001 and 0.1 ppm of organophosphorus pesticides. This high sensitive test card provides a useful tool for detection of toxic organophosphorus and carbamate compounds in agricultural products, food and environment with cost-effective, minimized reagent consumption, and simple operation.

The estimation of oxime efficiency is affected by the experimental design of phosphylated acetylcholinesterase reactivation

Reactivation of acetylcholinesterase (AChE), an essential enzyme in neurotransmission, is a key point in the treatment of acute poisoning by nerve agents and pesticides, which structurally belong to organophosphorus compounds (OP). Due to the high diversity of substituents on the phosphorous atom, there is a variety of OP-AChE conjugates deriving from AChE inhibition, and therefore not only is there no universal reactivator efficient enough for the most toxic OPs, but for some nerve agents there is still a lack of any reactivator at all. The endeavor of many chemists to find more efficient reactivators resulted in thousands of newly-designed and synthesized oximes−potential reactivators of AChE. For an evaluation of the oximés reactivation efficiency, many research groups employ a simple spectrophotometric Ellman method. Since parameters that describe reactivator efficiency are often incomparable among laboratories, we tried to emphasize the critical steps in the determination of reactivation parameters as well as in the experimental design of a reactivation assay. We highlighted the important points in evaluation of reactivation kinetic parameters with an aim to achieve better agreement and comparability between the results obtained by different laboratories and overall, a more efficient evaluation of in vitro reactivation potency.

Improved Hydrolysis of Organophosphorus Compounds by Engineered Human Prolidases.

Human prolidase has weak hydrolytic activity for toxic organophosphorus compounds including diisopropyl fluorophosphates (DFP), chemical warfare nerve agents and pesticides. In order to use human prolidase as a catalytic bioscavenger against toxic organophosphorus compound exposure, protein engineering is an important issue to improve the catalytic activity of human prolidase towards the hydrolysis of toxic organophosphorus compounds. We developed two human prolidase mutants, A252R and P365R, with a single amino acid substitution using in silico analysis based on the sequence, protein structure and stability to improve the catalytic activity of human prolidase towards DFP hydrolysis. Our results showed that the catalytic efficiencies of A252R and P365R towards DFP hydrolysis were 1.23- and 1.36-fold increases, respectively, than that of the wild type, while the prolidase activities of A252R and P365R towards Leu-Pro hydrolysis were 0.88- and 0.78-fold decreases that of the wild type, respectively, indicating that substitution mutations of A252R and P365R in human prolidase show improved hydrolytic activity for toxic organophosphorus compounds. We report here that by introducing either the A252R or P365R substitution mutation, the structural changes affecting catalytic turnover rate and substrate binding affinity are valuable in improving the catalytic activity of human prolidase towards toxic organophosphorus compound hydrolysis.

Development of a sensitive, generic and easy to use organophosphate skin disclosure kit

Various organophosphorus compounds (OP), primarily the nerve agent VX and other V-agents, are highly toxic to humans after skin exposure. Percutaneous exposure by such OP results in a delayed onset of toxic signs which enables the initiation of specific countermeasures if contamination is detected rapidly. Presently available mobile detection systems can hardly detect skin exposure by low volatile OP. In order to fill this gap an OP skin disclosure kit was developed which should fulfill different requirements, i.e. ▪ a high sensitivity, ▪ coverage of human toxic OP, ▪ easy handling, ▪ rapid results, ▪ small dimension and weight. The kit includes a cotton swab to sample skin, human AChE as target and chemicals for a color reaction based on the Ellman assay which is recorded by visual inspection. OP is dissolved from the sampler in a test tube filled with phosphate buffer (0.1M, pH 7.4) and incubated with lyophilized human AChE for 1min. The reaction with acetylthiocholine and 5,5′-dithio-bis-2-nitrobenzoic acid (1min) results in a rich yellow color in the absence of OP and in contrast, in transparent or pale yellow buffer in the presence of OP. At the recommended conditions, the limit of detection is 100ng VX and Russian VX and 50ng Chinese VX on plain surface and 200ng VX on rat skin. With activated pesticides, paraoxon and malaoxon, a concentration of ∼10μg can be detected on plain surface. The ready-to-use kit has a weight of 16g and a size of 10×12×1cm. In the end, this kit has the potential to fill a major gap and to enable timely detection of OP skin exposure and initiation of life-saving countermeasures.

A highly specific BODIPY-based fluorescent probe for the detection of nerve-agent simulants

Nerve agents such as Sarin, Soman and Tabun are all very toxic organophosphorus (OP) compounds capable of being used as chemical weapons. Unfortunately, the ability to rapidly sense OPCs is still an ongoing challenging. In this report, we designed and synthesized a fast-response fluorescent probe (1) for the detection of OP nerve agent simulants with high selectivity and sensitivity. The probe contains an electron donor-to-acceptor system in which a BODIPY moiety acts as a reporter group and the hydroxyl group as a reaction site for nerve agent simulants. The electron deficient nitrile group was introduced to lower the background fluorescence of the probe. A significant enhancement of fluorescence intensities at 531nm was observed upon gradual addition of nerve agent simulants on excitation at 480nm. The emission intensity rapidly reached its maximum within only 540s on adding 6 equiv. of nerve agent simulants with a quantum yield of the reaction product of 0.808, 81-fold larger than the probe itself (Ф=0.01). A color change in following a paper test experiment verified its portable application.

4R-Cembranoid Improves Outcomes after 6-Hydroxydopamine Challenge in Both In vitro and In vivo Models of Parkinson's Disease.

(1S, 2E, 4R, 6R,-7E, 11E)-2, 7, 11-cembratriene-4, 6-diol (4R) is one of the cembranoids found in tobacco leaves. Previous studies have found that 4R protected acute rat hippocampal slices against neurotoxicity induced by N-methyl-D-aspartate (NMDA) and against the toxic organophosphorus compounds paraoxon and diisopropylfluorophosphate (DFP). Furthermore, in vivo, 4R reduced the infarct size in a rodent ischemic stroke model and neurodegeneration caused by DFP. The present study expanded our previous study by focusing on the effect of 4R in Parkinson's disease (PD) and elucidating its underlying mechanisms using 6-hydroxydopamine (6-OHDA)-induced injury models. We found that 4R exhibited significant neuroprotective activity in the rat unilateral 6-OHDA-induced PD model in vivo. The therapeutic effect was evident both at morphological and behavioral levels. 4R (6 and 12 mg/kg) treatments significantly improved outcomes of 6-OHDA-induced PD in vivo as indicated by reducing forelimb asymmetry scores and corner test scores 4 weeks after injection of 6-OHDA (p < 0.05). The therapeutic effect of 4R was also reflected by decreased depletion of tyrosine hydroxylase (TH) in the striatum and substantia nigra (SN) on the side injected with 6-OHDA. TH expression was 70.3 and 62.8% of the contralateral side in striatum and SN, respectively, after 6 mg/kg 4R treatment; furthermore, it was 80.1 and 79.3% after treatment with 12 mg/kg of 4R. In the control group, it was 51.9 and 23.6% of the contralateral striatum and SN (p < 0.05). Moreover, 4R also protected differentiated neuro-2a cells from 6-OHDA-induced cytotoxicity in vitro. The activation of p-AKT and HAX-1, and inhibition of caspase-3 and endothelial inflammation, were involved in 4R-mediated protection against 6-OHDA-induced injury. In conclusion, the present study indicates that 4R shows a therapeutic effect in the rat 6-OHDA-induced PD model in vivo and in 6-OHDA-challenged neuro-2a cells in vitro.

Fluorescent Chemosensors with Varying Degrees of Intramolecular Charge Transfer for Detection of a Nerve Agent Mimic in Solutions and in Vapor.

Nerve agents are highly toxic organophosphorus compounds, and their possible use in terrorist attacks has led to increasing interest in the development of reliable and accurate methods to detect these lethal chemicals. In this paper, we have prepared six 6-aminoquinolines with various N-substituents as chemosensors for a nerve-agent mimic diethylchlorophosphate (DCP). The chemosensors with the nucleophilic pyridine-N atom as the active site detect DCP via a catalytic hydrolysis approach to form the protonated sensor. The nucleophilicity of the pyridine-N atom depends on the donating ability of the 6-amine group, which affects the intramolecular charge-transfer (ICT) character of sensors and the protonated sensors, leading to different fluorescence-response modes. The effects of the ICT character on the sensing property have been clarified. Among these charge transfer sensors, the sensor 3 displays ratiometric fluorescence response to DCP and a low limit of detection (8 nM). Furthermore, a facile testing strip with 3 has been fabricated with poly(ethylene oxide) for real-time selective monitoring of DCP vapor.

Investigation of paraoxonase 1 activity of the workers at the plant, who have long-term contact with organophosphorus compounds

Background. Liver enzyme paraoxonase 1 (PON1) plays an important role in protection the organism from toxic effects of organophosphorus compounds (OPs) via their hydrolysis whose rate and efficiency depend on PON1 serum level activity. PON1 activity is largely determined by the polymorphic variants of the PON1 gene. Effect of long-term work with exposure to the toxic OPs on the PON1 activity is almost unknown. The aim of the present work was to study the effect of long-term work with exposure to the toxic OPs on PON1 serum enzymatic activity depending on polymorphisms Q191R, L54M, C(-108)T PON1 gene. Materials and methods. PON1 serum enzymatic activity and PON1 polymorphisms were determined in men, who were categorized in 2 groups: workers of companies providing storage and disposal of the OPs (68) and control group (37). The PON1 191, PON1 55 and PON1 108 polymorphisms were studied by polymerase chain reaction/restriction fragment length polymorphism. PON1 serum enzymatic activity was measured by a spectrophotometric method using paraoxon. Results. PON1 activity in workers with exposure to the toxic OPs relative was increased compared to the control group (p = 0,027). Differences in serum PON1 activity was shown for the carriers of certain genotypes of the PON1 gene: PON1 serum activity was higher in workers compared to controls only for LL genotype (L54M polymorphism) and C allele (C(-108)T polymorphism) carriers (p 0,001 and p = 0,002, correspondently). Conclusion. We suggest that the increase in serum PON1 activity in workers providing storage and disposal of OPs could be modulated with the polymorphic variants of the PON1 gene.

Expression and purification of biologically active recombinant human paraoxonase 1 from a Drosophila S2 stable cell line

Many pesticides and chemical warfare nerve agents are highly toxic organophosphorus compounds (OPs), which inhibit acetylcholinesterase activity. Human paraoxonase 1 (PON1) has demonstrated significant potential for use as a catalytic bioscavenger capable of hydrolyzing a broad range of OPs. However, there are several limitations to the use of human PON1 as a catalytic bioscavenger, including the relatively difficult purification of PON1 from human plasma and its dependence on the presence of hydrophobic binding partners to maintain stability. Therefore, research efforts to efficiently produce recombinant human PON1 are necessary. In this study, we developed a Drosophila S2 stable cell line expressing recombinant human PON1. The recombinant human PON1 was fused with the human immunoglobulin Fc domain (PON1-hFc) to improve protein stability and purification efficiency. We purified the recombinant human PON1-hFc from the S2 stable cell line and characterized its enzymatic properties for OP hydrolysis. We purified the recombinant human PON1-hFc from the S2 stable cell line and characterized its enzymatic properties for OP hydrolysis compared with those of the recombinant human PON1 derived from E. coli. We observed that the recombinant human PON1-hFc is functionally more stable for OP hydrolyzing activities compared to the recombinant human PON1. The catalytic efficiency of the recombinant PON1-hFc towards diisopropyl fluorophosphate (DFP, 0.26 × 106 M−1 min−1) and paraoxon hydrolysis (0.015 × 106 M−1 min−1) was 1.63- and 1.24-fold higher, respectively, than the recombinant human PON1. Thus, we report that the recombinant PON1-hFc exerts hydrolytic activity against paraoxon and DFP.

From simple in vitro test to complex models: The example of developmental toxicity of organophosphorus compounds

From simple in vitro test to complex models: The example of developmental toxicity of organophosphorus compounds

Exploration of Unimolecular Gas-Phase Detoxication Pathways of Sarin and Soman: A Computational Study from the Perspective of Reaction Energetics and Kinetics.

A mechanistic investigation has been carried out to explore all possible gas phase unimolecular isomerization as well as decomposition pathways of toxic organophosphorus compounds (OPCs), namely, sarin (GB) and soman (GD), which are better known as nerve agents. We have identified a total of 13 detoxication pathways for sarin, where the α-H, β-H, and γ-H take part in the H-transfer process. However, for soman, due to the presence of ω-H, three additional detoxication pathways are obtained, where the ω-H is involved in the H-transfer process. Among all the pathways, the D3 decomposition pathway, where the phosphorus oxoacid derivative and alkene are generated via the formation of a six-membered ring in the transition state, is identified as the most feasible pathway from the perspective of both activation barrier and reaction enthalpy values. Moreover, we have studied the feasibility of the isomerization and decomposition pathways by performing the reaction kinetics in the temperature range of 300 K-1000 K using the one-dimensional Rice-Ramsperger-Kassel-Marcus (RRKM) master equation. From the RRKM calculation also, D3 pathway is confirmed as the most feasible pathway for both OPCs. The rate constant values associated with the D3 pathway within the temperature range of 600 K-700 K imply that the degradation of the OPCs is possible within this temperature range via the D3 pathway, which is in good agreement with the earlier reported experimental result. It is also observed that at higher temperature range (∼900 K), the increased rate constant values of other detoxication pathways indicate that along with D3, all other pathways become more or less equally feasible. Therefore, the entire work provides a widespread idea about the kinetic as well as thermodynamic feasibility of the explored detoxication pathways of the titled OPCs.

Asymmetric biocatalysis of the nerve agent VX by human serum paraoxonase 1: molecular docking and reaction mechanism calculations

Organophosphorus compounds have been employed in agricultural activity for a long time, causing serious public health problems. Due to their toxic properties, these compounds have also been used as chemical weapons. In view of this scenario, the catalytic degradation and the development of bioremediation processes of organophosphorus compounds have been of wide interest. Among several enzymes capable of degrading organophosphorus compounds, the human serum paraoxonase 1 has shown good potential for this purpose. To evaluate the interaction mode between the human serum paraoxonase 1 (wild-type and mutants) enzymes and the VX compound, one of the most toxic organophosphorus compounds known, molecular docking calculations were conducted. In addition, seeking to analyze the reaction pathway and the stereochemistry preference by human serum paraoxonase 1 and the R p and S p enantiomers of VX, quantum mechanical/molecular mechanics calculations were performed. Our theoretical findings put in evidence that the wild-type and mutant human serum paraoxonase 1 enzymes strongly interact with VX. Moreover, with the quantum mechanical/molecular mechanics study, we observed that the human serum paraoxonase 1 preferentially degrades one enantiomer in relation to the other. The current results indicate key points for designing new, more efficient mutant human serum paraoxonase 1 enzymes for VX degradation.

Acetylcholine-hydrolyzing activities in soluble brain fraction: Characterization with reversible and irreversible inhibitors

Some effects of organophosphorus compounds (OPs) esters cannot be explained through actions on currently recognized targets acetylcholinesterase or neuropathy target esterase (NTE). In soluble chicken brain fraction, three components (Eα, Eβ and Eγ) of pheny lvalerate esterase activity (PVase) were kinetically discriminated and their relationship with acetylcholine-hydrolyzing activity (cholinesterase activity) were studied in previous works. In this work, four enzymatic components (CS1, CS2, CS3 and CS4) of cholinesterase activity have been discriminated in soluble fraction, according to their sensitivity to irreversible inhibitors mipafox, paraoxon, PMSF and iso-OMPA and to reversible inhibitors ethopropazine and BW284C51. Cholinesterase component CS1 can be related to the Eα component of PVase activity and identified as butyrylcholinesterase (BuChE). No association and similarities can be stablished among the other PVase component (Eβ and Eγ) with the other cholinesterase components (CS2, CS3, CS4). The kinetic analysis has allowed us to stablish a method for discriminating the enzymatic component based on a simple test with two inhibitors. It can be used as biomarker in toxicological studies and for monitoring these cholinesterase components during isolation and molecular identification processes, which will allow OP toxicity to be understood by a multi-target approach.

Reactive adsorption of toxic organophosphates parathion methyl and DMMP on nanostructured Ti/Ce oxides and their composites

Pure titanium and cerium oxides and their composites were prepared by the modified method of homogeneous hydrolysis with urea as the precipitating agent. The as-synthesized nanostructured oxides were examined by XRD, XPS, microscopic techniques (SEM, HRTEM), nitrogen physisorption, and vibrational spectroscopies (FTIR, Raman). Decontamination ability of the samples towards the toxic organophosphorus compounds was determined by two methods. The reactive adsorption of the warfare agent simulant Dimethyl methylphosphonate (DMMP) was observed by in situ FTIR spectroscopy. The degradation of the pesticide parathion methyl in a liquid medium was investigated by liquid chromatography (HPLC). Nano-ceria exhibited substantially higher degradation ability compared to nano-titania. The highest degradation efficiency was achieved with the composites with Ti:Ce 2:8 and 1:1 molar ratio. The strong interaction of Ti with Ce led to an increase of Ce3+ and formation of Ti<4+ states and changed surface area and porosity which may cause improved degradation efficacy for both DMMP and parathion methyl.

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds.

The aim of this review is to provide an update on the current use of cyclodextrins against organophosphorus compound intoxications. Organophosphorus pesticides and nerve agents play a determinant role in the inhibition of cholinesterases. The cyclic structure of cyclodextrins and their toroidal shape are perfectly suitable to design new chemical scavengers able to trap and hydrolyze the organophosphorus compounds before they reach their biological target.

Butyrylcholinesterase identification in a phenylvalerate esterase-enriched fraction sensitive to low mipafox concentrations in chicken brain.

Multiple epidemiological and experimental studies have demonstrated that exposure to organophosphorus compounds (OPs) is associated with a variety of neurological disorders. Some of these exposure symptoms cannot be precisely correlated with known molecular targets and mechanisms of toxicity. Most of the known molecular targets of OPs fall in the protein family of serine esterases. We have shown that three esterase components in the soluble fraction of chicken brain (an animal model frequently used in OP neurotoxicity assays) can be kinetically distinguished using paraoxon, mipafox and phenylmethyl sulfonyl fluoride as inhibitors, and phenyl valerate as a substrate; we termed them Eα, Eβ and Eγ. The Eα-component, which is highly sensitive to paraoxon and mipafox and resistant to PMSF, has shown sensitivity to the substrate acetylthiocholine, and to ethopropazine and iso-OMPA (specific inhibitors of butyrylcholinesterase; BChE) but not to BW 284C51 (a specific inhibitor of acetylcholinesterase; AChE). In this work, we employed a large-scale proteomic analysis B with a LC/MS/MS TripleTOF system; 259 proteins were identified in a chromatographic fractionated sample enriched in Eα activity of the chicken brain soluble fraction. Bioinformatics analysis revealed that BChE is the only candidate protein identified to be responsible for almost all the Eα activity. This study demonstrates the potential information to be gained from combining kinetic dissection with large-scale proteomics and bioinformatics analyses for identification of proteins that are targets of OP toxicity and may be involved in detoxification of phosphoryl and carbonyl esters.

Mesoporous manganese oxide for the degradation of organophosphates pesticides

Manganese(IV) oxide used for degradation of toxic organophosphorus compounds was prepared by homogeneous hydrolysis of potassium permanganate (KMnO4) with 2-chloroacetamide. The prepared sample was characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and nitrogen physisorption. The degradation efficiency was determined with parathion methyl (PM) as representative of organophosphate pesticides using high-performance liquid chromatography. For a comparison, the commercially obtained product and the two synthesized manganese(IV) oxides prepared by direct reaction of manganese(II) sulfate (MnSO4·H2O) and potassium permanganate (KMnO4) and potassium permanganate (KMnO4) with urea in aqueous solution were tested. The sample prepared by homogeneous hydrolysis of KMnO4 with 2-chloroacetamide showed the highest degradation efficacy. The reaction half-time in non-polar organic solvent (n-heptane) was around 0.9 min with the degradation efficiency of about 90 % within 2 h. It was shown that comparative samples of manganese(IV) oxides were variously effective in decomposition of PM by cleavage of the P–O-aryl bond in the pesticide molecule. The degradation mechanism for PM on the MnO2 surfaces was proposed.

Dramatic Increase in Cerebral Blood Flow following Soman Intoxication If Signs of Symptoms Can Be Seen

Organophosphate poisoning is associated with adverse effects on the central nervous system such as seizure/convulsive activity and long term changes in neuronal networks. This study report an investigation designed to assess the consequences of Soman, a highly toxic organophosphorus compound, exposure on regional blood flow in the rat brain and peripheral organs. We performed repeated blood flow measurements in the same animal, using the microspheres technique, to characterize changes in regional blood flow at different times after Soman intoxication. In addition, the cardiopulmonary effects of Soman were followed during the intoxication. Administration of Soman (1 LD50; 90 µg/kg, s.c.) to anaesthetized rats produced a decrease in blood acetylcholinesterase activity in all animals tested. Although, only six out of ten rats showed signs of poisoning like a decrease in respiratory rate, the results show that only animals with significant signs of poisoning demonstrated an increase in cerebral blood flow. We conclude that it is of great importance to treat all data individually. An overall mean can easily be misinterpreted and conceal important effects. We also conclude that the increase in cerebral blood flow has an important role in the effect on respiration and that this effect is independent of the blood acetylcholinesterase activity.

Engineering the Organophosphorus Acid Anhydrolase Enzyme for Increased Catalytic Efficiency and Broadened Stereospecificity on Russian VX.

The enzyme organophosphorus acid anhydrolase (OPAA), from Alteromonas sp. JD6.5, has been shown to rapidly catalyze the hydrolysis of a number of toxic organophosphorus compounds, including several G-type chemical nerve agents. The enzyme was cloned into Escherichia coli and can be produced up to approximately 50% of cellular protein. There have been no previous reports of OPAA activity on VR {Russian VX, O-isobutyl S-[2-(diethylamino)ethyl] methylphosphonothioate}, and our studies reported here show that wild-type OPAA has poor catalytic efficacy toward VR. However, via application of a structurally aided protein engineering approach, significant improvements in catalytic efficiency were realized via optimization of the small pocket within the OPAA's substrate-binding site. This optimization involved alterations at only three amino acid sites resulting in a 30-fold increase in catalytic efficiency toward racemic VR, with a strong stereospecificity toward the P(+) enantiomer. X-ray structures of this mutant as well as one of its predecessors provide potential structural rationales for their effect on the OPAA active site. Additionally, a fourth mutation at a site near the small pocket was found to relax the stereospecificity of the OPAA enzyme. Thus, it allows the altered enzyme to effectively process both VR enantiomers and should be a useful genetic background in which to seek further improvements in OPAA VR activity.

Efficient Surface Display of Diisopropylfluorophosphatase (DFPase) in E. coli for Biodegradation of Toxic Organophosphorus Compounds (DFP and Cp).

Compounds including organophosphorus pesticides (OPs) and chemical nerve agents are toxic compounds synthesized recently which disrupt the mechanisms of neural transmission. Therefore, a critical requirement is the development of a bio-refining technology to facilitate the biodegradation of organophosphorus pollutants. The diisopropylfluorophosphatase (DFPase, EC 3.1.8.2) from the ganglion and brain of Loligo vulgaris acts on P-F bonds present in some OPs. Intracellular production of OPs-degrading enzymes or the use of native bacteria and fungi leads to a low degradation rate of OPs due to a mass transfer issue which reduces the overall catalytic efficiency. To overcome this challenge, we expressed DFPase on the surface of E. coli for the first time by employing the N-terminal domain of the ice nucleation protein (InaV-N) as an anchoring motif. Tracking the recombinant protein confirmed that DFPase is successfully located on the outer membrane. Further studies on its activity to degrade diisopropylfluorophosphate (DFP) showed its significant ability for the biodegradation of diisopropylfluorophosphate (DFP) with a specific activity of 500 U/mg of wet cell weight. Recombinant cells could also degrade chlorpyrifos (Cp) with an activity equivalent to a maximum value of 381.44 U/ml with a specific activity of 476.75 U/mg of cell, analyzed using HPLC technique. The optimum activity of purified DFPase was found at 30 °C. A more increased activity was also obtained in the presence of glucose-mineral-salt (GMS) supplemented with tryptone and 100 mg/L Co(2+) ion. These results highlight the high potential of the InaV-N anchoring domain to produce an engineered bacterium that can be used in the bioremediation of pesticide-contaminated environments.