Expressing organophosphorus

Comparison of whole cell biocatalytic reaction kinetics for recombinant Escherichia coli with periplasmic-secreting or cytoplasmic-expressing organophosphorus hydrolase... 

A. Mulchandani, I. Kaneva, and W. Chen, Biosensor for direct determination of organophosphate nerve agents using recombinant Escherichia coli with surface-expressed organophosphorus hydrolase. 2. Fiber-optic microbial biosensor. Anal. Chem. 70, 5042-5046 (1998). 

Richins RD, Kaneva I, Mulchandani A et al. Biodegradation of organophosphorus pesticides by surface-expressed organophosphorus hydrolase. Nat Biotechnol 1997 15(10) 984-987. 

Mulchandani P, Chen W, Mulchandani A et al. Amperometric microbial biosensor for direct determination of organophosphate pesticides using recombinant microorganism with surface expressed organophosphorus hydrolase. Biosens Bioelectron 2001 16(7-8) 433-437. 

Mulchandani A., Kaneva I., and Chen W., Detoxification of organophosphate nerve agents by immobilized Escherichia coli with surface-expressed organophosphorus hydrolase, Biotechnol. Bioeng., 63, 216-223, 1999. 

Cheng T-C, SP Harvey, GL Chen (1996) Cloning and expression of a gene encoding a bacterial enzyme for decontamination of organophosphorus nerve agents and nucleotide sequence of the enzyme. Appl Environ Microbiol 62 1636-1641. 

Newcomb R. D., Campbell P. M., Russell R. J. and Oakeshott J. G. (1997) cDNAcloning, baculovirus-expression and kinetic properties of the esterase, E3, involved in organophosphorus resistance in Lucilia cuprina. Insect Biochem. Mol. Biol. 27, 15— 25. 

Sweeney, R.E., Maxwell, D.M. (2003). A theoretical expression for the protection associated with stoichiometric and catalytic scavengers in a single compartment model of organophosphorus poisoning. Math. Biosci. 181 133 3. 

Millard, C.B., Lockridge, O., Broomfield, C.A. (1995). Design and expression of organophosphorus acid anhydride hydrolase activity in human butyrylcholinesterase. Biochemistry 34 15925-33. 

Wang, Y., Boeck, A.T., Duysen, E.G., van Keuren, M., Saunders, T.L., Lockridge, O. (2004). Resistance to organophosphorus agent toxicity in transgenic mice expressing the G117H mutant of human hutyrylcholinesterase. Toxicol. Appl. Pharmacol. 196 356-66. 

The report by Haas and Guardia (18) pertains to their efforts to apply immunological methods for the assay of pesticide residues, and expresses their aim to test the suitability of methods for field analytical purposes. Haas and Guardia also used DDT and malathion to represent two of the most important classes of insecticides, chlorinated hydrocarbons and organophosphorus compounds. They first attempted to prepare insecticide-protein antigens in which enzymes were used as the protein carrier. Antiserum of rabbits injected with DDA-carbonic anhydrase or malathion-chymotrypsin failed to show the presence of the respective antibodies. 

Richins, R.D., A. Mulchandani, and W. Chen. 2000. Expression, immobilization, and enzymatic characterization of cellulose-binding domain-organophosphorus hydrolase fusion enzymes. Biotechnology and Bioengineering 69(6) 591-596. 

Organophosphorus insecticides give very stable acylated enzymes (AE does not hydrolyze because +3 is very small). The potency of an inhibitor is much determined by how stable the Michaelis complex is (as expressed by the size of Kd) and how fast the acylated enzyme is formed (expressed as the size of k+2). A constant including Kd and k+2, called the bimolecular inhibition constant, is often used to describe the strength of an inhibitor because it is very easy to determine experimentally and it tells us how potent the inhibitor is ... 

Wallace, T. J., Ghosh, S., and McLean Grogan, W. (1999). Molecular cloning and expression of rat lung carboxylcstcra.se and its potential role in the detoxification of organophosphorus compounds. Am. J. Respir. Cell. Mol. Biol. 20, 1201—1208. 

Although there is nu doubt (hut humans are exposed to low doses of mixtures of pesticides (Caslorina e( at, 2003 Duggan et ai, 2003 Fenskc et al. 2002 Sanchez-Pena et ai, 2004), the question is whether mixtures are more toxic than the sum of the toxicity for each pesticide alone. In the literature describing the toxicity of mixtures of organophosphorus (OP) or carbamate (CM) pesticides, concern is expressed that exposure to mixtures of pesticides may be much more toxic than the toxicity of the individual pesticides. This concern about potentiated toxicity is all the more worrisome because data are lacking on the toxicity of pesticide mixtures, whether OP or CM, at less than lethal dosages. There is such scarcity of data, and the data arc so disparate, that a science-ba.scd conclusion on the toxicity of OP or CM pesticide mixtures is not possible,... 

Wu C.F., Cha H.J., Rao G., Valdes J.J. and Bentley W.E. 2000. A green fluorescent protein fusion strategy for monitoring the expression, cellular location, and separation of biologically active organophosphorus hydrolase. Appl. Microbiol. Biotechnol., 54, 78-83. 

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