Here, we describe the development of a bi-enzymatic biosensor that simplifies the sample pretreatment steps for insecticide detection, and opens the way for a highly sensitive detection of phosphorothionates in food. These compounds evolve their inhibitory activity towards acetylcholinesterases (AChEs) only after oxidation, which is performed in vivo by P450 monooxygenases. Consequently, phosph...

Empirical studies suggest that the antidotal effect of pralidoxime depends on plasma concentrations with therapeutic effects associated with concentrations above 4 mg/l. The purpose of this study was to determine the pharmacokinetic-toxicodynamic (PK-TD) relationships for the antidotal effect of pralidoxime on paraoxon-induced toxicity in rats. Diethylparaoxon inactivation of whole-blood cholin...

A novel thermostable arylesterase, a 35-kDa monomeric enzyme, was purified from the thermoacidophilic archaeon Sulfolobus solfataricus P1. The optimum temperature and pH were 94 degrees C and 7.0, respectively. The enzyme displayed remarkable thermostability: it retained 52% of its activity after 50 h of incubation at 90 degrees C. In addition, the purified enzyme showed high stability against ...

A potentiometric microbial biosensor for the direct measurement of organophosphate (OP) nerve agents was developed by modifying a pH electrode with an immobilized layer of Escherichia coli cells expressing organophosphorus hydrolase (OPH) on the cell surface. OPH catalyzes the hydrolysis of organophosporus pesticides to release protons, the concentration of which is proportional to the amount o...

INTRODUCTION Paraoxonase (PON1) is an enigmatic enzyme with multiple enzymatic properties including arylesterase and lactonase activities besides its ability to hydrolyze the toxic metabolite of parathion, paraoxon. The aim of this study was to determine the phenotype distribution of PON1 in patients with cardiac disease who were classified in coronary artery bypass grafting (CABG), heart valve...

An improved whole-cell technology for detoxifying organophosphate nerve agents was recently developed based on genetically engineered Escherichia coli with organophosphorus hydrolase anchored on the surface. This article reports the immobilization of these novel biocatalysts on nonwoven polypropylene fabric and their applications in detoxifying contaminated wastewaters. The best cell loading (2...

The nerve agents soman, sarin, VX, and tabun are deadly organophosphorus (OP) compounds chemically related to OP insecticides. Most of their acute toxicity results from the irreversible inhibition of acetylcholinesterase (AChE), the enzyme that inactivates the neurotransmitter acetylcholine. The limitations of available therapies against OP poisoning are well recognized, and more effective anti...

The synthetic procedures for a large-scale preparation of o- and p-nitrophenyl 2-acetamido-2-deoxy-α-D-mannopyranoside are described. The synthetic pathway employs the glycosylation of phenol with ManNAc oxazoline, followed by nitration of the aromatic moiety yielding a separable mixture of the o- and p-nitrophenyl derivative in a 2:3 ratio.