In vitro hydrolysis of paraoxon by parathion resistant houseflies

Welling, W.; Blaakmeer, P.; Vink, G.J.; Voerman, S.

doi:10.1016/0048-3575(71)90211-2

Cited by 35 publications

(5 citation statements)

References 9 publications

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“…virescens 11,12) but its high K m for OPs (Ͼ700 mM, c.f. Ͻ Ͻ1 mM for the dipteran esterases that confer OP resistance 13,14) ) casts doubt on its physiological relevance. And there are at least two genetic mechanisms by which detoxifying enzymes not causally involved in a particular resistance could nevertheless show an association with resistance.…”

Section: Heliothine Resistance To Opsmentioning

confidence: 99%

Esterase-based metabolic resistance to insecticides in heliothine and spodopteran pests

Farnsworth

Teese

Yuan

et al. 2010

Journal of Pesticide Science

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IntroductionCarboxylesterases have been implicated in metabolic resistance to several classes of insecticide in a wide variety of pest insect species. [1][2][3] The classes most commonly involved are synthetic pyrethroids (SPs) and organophosphates (OPs), and carbamates (CBs) are also involved in several cases. There are also occasional reports of carboxylesterase phenotypes associated with resistance to benzoylureas, the oxadiazine indoxacarb, the diacylhydrazine tebufenozide, the organochlorine endosulfan and the proteinaceous Cry1Ac toxin of Bacillus thuringiensis that is expressed in transgenic crops. Figure 1 gives structures for some key compounds among these various classes of insecticide.It might be expected that carboxylesterases would be involved in SP resistance because the great majority of SPs are carboxylesters. However, no precise molecular mechanisms for esterase-based SP resistance have yet been elucidated in any insect. OPs are generally phosphotriesters rather than carboxylesters but nevertheless they bind many carboxylesterases with high affinity and this provides a basis for two forms of resistance, both now elucidated at a molecular level in several species. One form involves substantial overexpression of the esterase, allowing for effective sequestration of the insecticide. The other involves specific mutations in the active site of the enzyme which convert it to an OP hydrolase (the so-called "mutant ali-esterase" mechanism). CBs are carbamic acid (NH 2 COOH) derivatives, in which a functional group has been added as an ester; these esters are chemically similar to carboxylesters. Carbamates bind carboxylesterases with quite high affinity, but as yet the molecular mechanisms by which a (mutant) carboxylesterase confers CB resistance have not been elucidated in any species. Of the other insecticide classes occasionally linked to esterase-based resistance only indoxacarb has ester bonds (two Elevated esterase activities and increased band intensities of multiple esterase isozymes after electrophoresis are commonly associated with resistance to organophosphate, pyrethroid and carbamate insecticides in various heliothine and spodopteran pests. One possible explanation for this involves a 'master regulator' mutation in a more general chemical stress response. An association between elevated esterase activities and isozyme intensities has also been reported for resistance to the Cry1Ac toxin of Helicoverpa armigera. The basis for this is unclear albeit some involvement of esterases could be mediated by the toxin's affinity for N-acetyl galactosamine glycans on certain gut-expressed esterases in this species.

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Section: Heliothine Resistance To Opsmentioning

confidence: 99%

Esterase-based metabolic resistance to insecticides in heliothine and spodopteran pests

Farnsworth

Teese

Yuan

et al. 2010

Journal of Pesticide Science

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“…Nakatsugawa et al (48,49) reported that DETP was released from PTN in eucaryotes primarily by microsomal oxygenases but not by non-oxidative hydrolytic enzymes. The hydrolysis of PTN by "thionase" enzymes was reported by Matsumura and Hogendijk (42) to occur in PTN-resistant houseflies, but this postulated non-oxidative hydrolysis has since been questioned (48,71). One of the only reports of desulfuration of a thioate to an oxon by a microorganism concerned the intra-cellular desulfuration of Dyfonate to dyfoxon by soil fungi (16).…”

Section: Discussionmentioning

confidence: 99%

Parathion utilization by bacterial symbionts in a chemostat

Daughton¹,

Hsieh²

1977

Appl Environ Microbiol

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A continuous-culture device was used to select and enrich for microorganisms, from sewage and agricultural runoff, that were capable of using the organophosphorus insecticide parathion as a sole growth substrate. Parathion was dissimilated by the highly acclimated symbiotic activities of Pseudomonas stutzeri, which non-oxidatively and cometabolically hydrolyzed the parathion to ionic diethyl thiophosphate and p-nitrophenol, and P. aeruginosa, which utilized the p-nitrophenol as a sole carbon and energy source. Ionic diethyl thiophosphate was found to be inert to any transformations. Methyl parathion was dissimilated in an analogous way. The device functioned as a chemostat with parathion as the growth-limiting nutrient, and extraordinarily high dissimilation rates were attained for parathion (8 g/liter per day) and for p-nitrophenol (7 g/liter per day). This is the first report of parathion utilization by a defined microbial culture and by symbiotic microbial attack and of dissimilation of an organophosphorus pesticide in a chemostat. Continuous-cultivation techniques have rarely been used for studying the interactions of microorganisms and xenobiotics, e.g., microbial degradation of pesticides and toxic wastes.

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“…Since a partially purified enzyme preparation was used, it seems improbable that the mixed-function oxidases were involved in the reaction. However, according to Welling et al (1971) and Nakatsugawa et al (1969), they could not reproduce the results with [14C]parathion or [35S]parathion. Thus most of the recent reviewers Oppenoorth, 1971; Wilkinson, 1971) concluded that phosphates are preferred substrates for hydrolysis by phosphatase, but phosphorothioates probably are not.…”

Section: Malathionmentioning

confidence: 98%

“…The partially purified enzyme from the resistant strain showed higher activity against parathion than that of the susceptible strain and produced diethyl phosphorothioic acid. Welling et al (1971) investigated the in vitro degradation of paraoxon in resistant and susceptible strains of the housefly. The microsomal fraction of the resistant strain degraded paraoxon and produced diethyl phosphoric acid as the major product, as well as two other minor products.…”

Section: Malathionmentioning

confidence: 99%