Environmental applications of earthworm esterases in the agroecosystem

Abstract

Chemical control of pests is still necessary in agriculture, despite the growing efforts to introduce biocontrolbased strategies. Many studies have evidenced the harm of pesticide side-effects on natural populations of pest enemies and other non-target organisms. Moreover, pesticide-contaminated soils can act as a secondary pollution source causing contamination in environmental compartments of critical concern to public health (water resource). These environmental risks need to be assessed and monitored for decision-making related to the post-authorization management of pesticides. Under these considerations, earthworm esterases can be a suitable tool for these regulatory and environmental purposes. Herein, it is suggested the use of earthworm esterases as biomarkers to be included in a field toxicity test. Furthermore, the potential role of gut carboxylesterases (CEs) in the modulation of pesticide toxicity is discussed in view of their contribution to the natural tolerance of earthworms to pesticides, and consequently the appropriate selection of earthworm species for regulatory toxicity testing. Finally, it is postulated that CE secretion into the earthworm gut could be an environmental friendly methodology in the enzymatic bioremediation of pesticide-contaminated soils.

Toxicity, bioaccumulation and metabolism of pesticides in the earthworm

“…132) Their activity in the post-mitochondrial fraction is generally examined by spectrophotometrically monitoring hydrolysis product of a phenyl (thio) acetate derivative. Fenitrothion (E. fetida), 133) pirimiphosmethyl and deltamethrin (E. andrei), 134) and dimethoate (E. 135) significantly decreased the CaE activity in the paper contact test.…”

Acute toxicity of organophosphate fenitrothion on biomarkers in prawn Palaemonetes argentinus (Crustacea: Palaemonidae)

“…The primary physiological role of BChE is not completely clear, but some studies suggest that this enzyme may play an important role in the hydrolysis of acetylcholine at cholinergic synapses like AChE (Kristoff et al 2012). Also, BChE could play a protective role in anticholinesterase intoxication by removing the pesticide prior to reaching the target site AChE and contribute to the sensitivity of the species to anticholinesterase pesticides (Sanchez-Hernandez 2007). A number of studies have been performed to urge ChE as a biomarker for prediction of OPs in aquatic invertebrates (Day and Scott 1990;Monserrat et al 1997;Chang et al 2006;Frasco et al 2006;Liu et al 2012;Rivadeneira et al 2013).…”

Toxicity of Binary Mixtures of Enantiomers in Chiral Organophosphorus Insecticides: The Significance of Joint Effects Between Enantiomers

“…A previous study has shown that the highly toxic oxon metabolites had a greater affinity for carboxylesterases (CEs) than their parent compounds. 29 However, the in vitro AChE system was not able to oxidatively desulfurize the P = S moiety. Consequently, the affinity for the active site of AChE was lower for the enantiomers of fensulfothion in the in vitro system.…”

“…Phosphorothioate‐type organophosphate insecticides such as fensulfothion need to be bioactivated by monooxygenases. A previous study has shown that the highly toxic oxon metabolites had a greater affinity for carboxylesterases (CEs) than their parent compounds . However, the in vitro AChE system was not able to oxidatively desulfurize the P = S moiety.…”