The aqueous solubilities of 27 insecticides and related compounds were determined. Diazinon, fensulfothion and paraoxon had solubilities greater than reported in the literature. The presence of impurities and/or additional components in the mixture altered the measured solubility values. Addition of acetone in amounts up to 1% (volume) produced increases in parathion solubility up to 11%. The p...

SNF4435C and D are new immunosuppressants isolated from the culture broth of a strain of Streptomyces spectabilis. Their molecular formulas were determined as C28H31NO6 based on the HRFAB-MS analyses. The structures of SNF4435C and D were elucidated to be novel nitrophenyl pyrones having an intriguing tricyclic ring system and diastereoisomers of each other by spectroscopic analyses including v...

Rhipicephalus (Boophilus) microplus cDNAs, BmAChE1, BmAChE2, and BmAChE3, were previously identified as presumptively encoding acetylcholinesterases (AChEs), but biochemical identity was confirmed only for recombinant BmAChE3. In the present study, four recombinant BmAChE1 constructs and single recombinant constructs of BmAChE2 and BmAChE3 were expressed in baculovirus. Biochemical characteriza...

Certain organic phosphorus esters produce sensorimotor axonopathy in man and other species. There is an excellent correlation between the capacity of an organophosphorus compound to produce axonopathy and its ability to inhibit brain neurotoxic esterase (NTE) in hens. Because NTE is present in peripheral lymphocytes of both hen and man, it has been suggested that the lymphocyte enzyme might be ...

We have in vitro tested the ability of common, commercially available, cholinesterase reactivators (pralidoxime, obidoxime, methoxime, trimedoxime and HI-6) to reactivate human acetylcholinesterase (AChE), inhibited by five structurally different organophosphate pesticides and inhibitors (paraoxon, dichlorvos, DFP, leptophos-oxon and methamidophos). We also tested reactivation of human butyrylc...

A microbial biosensor for rapid, sensitive, selective, and cost-effective determination of the total content of organophosphorus nerve agents with p-nitrophenyl substituent is reported. The biosensor consisted of genetically engineered PNP-degrader Pseudomonas putida JS444 expressing organophosphorus hydrolase (OPH) on its cell surface immobilized on a dissolved oxygen electrode. Surface-expres...

The fluorogenic acetylesterase (acetic ester hydrolase EC 3.1.1.6.) substrate, fluorescein diacetate, was used to measure enzyme activity in living protist cells. The visual enzyme assay was done by monitoring fluorochromasia by fluorescent microscopy. Quantitative fluorogenic assays were done by measuring the evolved fluorescein in a fluorometer. Of 59 strains of bacteria, 35 were fluorochroma...

A potentiometric enzyme electrode for the direct measurement of organophosphate (OP) nerve agents was developed. The basic element of this enzyme electrode was a pH electrode modified with an immobilized organophosphorus hydrolase (OPH) layer formed by cross-linking OPH with bovine serum albumin (BSA) and glutaradehyde. OPH catalyses the hydrolysis of organophosphorus pesticides to release prot...

An optical biosensing method using CdTe quantum dots (QDs) and bi-enzyme-immobilized eggshell membranes for the determination of organophosphorus pesticides (OPs) has been developed. Increasing amounts of OPs led to a decrease of the enzymatic activity and thus a decrease in the production of hydrogen peroxide (H2O2), which can quench the fluorescence of the CdTe QDs. Under the optimum conditio...

Rapid and sensitive detection methods are in urgent demand for the screening of extensively used organophosphorus pesticides and highly toxic nerve agents for their neurotoxicity. In this study, we developed a novel Fe(3)O(4) magnetic nanoparticle (MNP) peroxidase mimetic-based colorimetric method for the rapid detection of organophosphorus pesticides and nerve agents. The detection assay is co...