Inhibition of cholinesterases and carboxylesterases of two invertebrate species, Biomphalaria glabrata and Lumbriculus variegatus, by the carbamate pesticide carbaryl
ABSTRACT In this study, the effects of sublethal concentrations of the carbamate carbaryl on the cholinesterase (ChE) and carboxylesterase (CES) activities present in the oligochaete Lumbriculus variegatus and in the pigmented Biomphalaria glabrata gastropod were investigated. The results showed that ChE activity from both species was inhibited by in vivo and in vitro exposure to carbaryl, with EC(50) and IC(50) values approximately 20 times lower for the oligochaete than for the gastropod. On the other hand, the recovery process in uncontaminated media was more efficient in oligochaetes than in snails. Thus, in only 2h the oligochaetes showed no inhibition with respect to control values whereas the snails did not reach control values even after 48h of being in pesticide-free water. CES activity was investigated in whole body soft tissue homogenates using three different substrates: p-nitrophenyl butyrate, 1-naphthyl acetate (NA) and 2-NA. In addition, the presence of multiple CES isozymes in L. variegatus and B. glabrata extracts, with activity towards 1- and 2-NA, was confirmed by native polyacrylamide electrophoresis. In both species, the activities measured using the naphthyl substrates were higher than the activity towards p-nitrophenyl butyrate. In addition, B. glabrata showed a higher CES activity than L. variegatus independently of the substrate used. In L. variegatus, in vivo CES activity towards the different substrates was less sensitive to carbaryl inhibition than ChE activity. In contrast, in B. glabrata, CES activity towards p-nitrophenyl butyrate was inhibited at lower insecticide concentrations than ChE. The results of this study contribute to the knowledge of the sensitivity of non-target freshwater invertebrate Type B-esterases towards pesticides.
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- "The success of this new class of insecticides is explained by their high efficacy across a wide range of insect species and safety regarding humans and other non-insect species. Diamide insecticides are thus replacing major uses of pyrethroids, neonicotinoids, carbamates and organophosphates (Damásio et al., 2011a, 2011b; Domingues et al., 2010; Fulton and Key, 2001; Guilhermino et al., 1996; Isaacs et al., 2012; Kristoff et al., 2010; Payne et al., 1996; Pest Management Regulatory Agency, PMRA, 2008). Nevertheless, chlorantraniliprole has been shown to be highly toxic to non-target invertebrates such as D. magna (EC 50 of 11.6 μg/L, immobilization) and other aquatic non-target species such as mayflies Table 1 Values of the Michaelis–Menten constant (K m ), maximal velocity (V max ), and the catalytic efficiency (V max /K m ) of Sericostoma vittatum cholinesterases for the three substrates tested. "
ABSTRACT: Sericostoma vittatum is a caddisfly species, endemic to the Iberian Peninsula, proposed as a biomonitor species for lotic ecosystems. Since inhibition of cholinesterases׳ (ChE) activity has been used to evaluate the exposure of macroinvertebrates to organophosphates and carbamate pesticides, this work intended to characterize the ChE present in this species so their activity can be used as a potential biomarker of exposure. Biochemical and pharmacological properties of ChE were characterized in this caddisfly species using different substrates (acetylthiocholine iodide, propionylthiocholine iodide, and butyrylthiocholine iodide) and selective inhibitors (eserine sulfate, BW284c51, and iso-OMPA). Also, the in vitro effects of two insecticides (carbaryl and chlorantraniliprole) and two psychiatric drugs (fluoxetine and carbamazepine) on ChE activity were investigated. The results suggest that S. vittatum possess mainly AChE able to hydrolyze both substrates acetylthiocholine and propionylthiocholine since: (1) it hydrolyzes the substrate acetylthiocholine and propionylcholine at similar rates and butyrylthiocholine at a much lower rate; (2) it is highly sensitive to eserine sulfate and BW284c51, but not to iso-OMPA; and (3) its activity is inhibited by excess of substrate, a characteristic of typical AChE. in vitro inhibitions were observed only for carbaryl exposure while exposure to chlorantraniliprole and to relevant environmental concentrations of psychiatric drugs did not cause any significant effect on AChE activity. This study suggests that AChE activity in caddisflies can indeed be used to discriminate the effects of specific insecticides in monitoring programs. The use of non-target species such as caddisflies in ecotoxicological research in lotic ecosystems is also discussed.Ecotoxicology and Environmental Safety 04/2014; 104C:263-268. DOI:10.1016/j.ecoenv.2014.03.012 · 2.76 Impact Factor
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- "Carboxylesterases (EC 220.127.116.11) activity was determined in 11,000xg supernatants obtained by homogenization in 20 mM Tris–HCl buffer (pH 7.5) plus 5 mM EDTA, according to Kristoff et al. (2010) "
ABSTRACT: In this study, the impact of technical grade glyphosate acid on Limnoperna fortunei was assessed employing outdoor microcosms treated with nominal glyphosate concentrations of 1, 3 and 6mgL(-1). At the end of the experiment (26 days), catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), acetylcholinesterase (AChE), carboxylesterases (CES) and alkaline phosphatase (ALP) activities, and lipid peroxidation levels were analyzed. GST and ALP activities and lipid peroxidation levels showed a significant increase with respect to controls in the mussels exposed to glyphosate (up to 90, 500 and 69 percent, respectively). CES and SOD activities showed a significant decrease in glyphosate exposed bivalves with respect to controls (up to 48 and 37 percent, respectively). CAT and AChE did not show differences between exposed and no exposed bivalves. The increase in lipid peroxidation levels and the decrease in SOD and CES activities observed in L. fortunei indicate that glyphosate had adverse effects on the metabolism of this bivalve. The results of the present study also indicate that a "multibiomarker approach" provides a more precise knowledge of the impact of glyphosate on L. fortunei.Ecotoxicology and Environmental Safety 06/2013; 95. DOI:10.1016/j.ecoenv.2013.05.024 · 2.76 Impact Factor
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- "Many studies have pointed out the interest of the measurement of AChE inhibition in aquatic invertebrates as exposure/effect biomarker in coastal waters and rivers (Moulton et al., 1996; Stien et al., 1998; Forget et al., 2003; Dailianis et al., 2003; Matozzo et al., 2005; Kristoff et al., 2010). There are several reasons why AChE inhibition in invertebrates could be very attractive in environmental monitoring. "
ABSTRACT: Acetylcholinesterase (AChE) is a key enzyme in the nervous system, terminating nerve impulses by catalyzing the hydrolysis of neurotransmitter acetylcholine. AChE is the target site of inhibition by organophosphorus and carbamate pesticides. In particular, organophosphorous pesticides inhibit the enzyme activity by covalently phosphorylating the serine residue within the active site group. They irreversibly inhibit AChE, resulting in excessive accumulation of acetylcholine, leading to the hyperactivities and consequently paralysis of the neural and muscle system. Therefore, monitoring of AChE inhibition is widely used as a biomarker of organophosphorous and carbamate exposure either in aquatic or terrestrial environments. Recently, new insights are emerging in the use of AChE as biomarker in environmental biomonitoring. A number of important contaminants other than carbamate and organophosphorus pesticides have recently been shown to have anticholinesterase properties, including heavy metals, detergents, hydrocarbons, and herbicides. It is also worth noting that not only different compounds may reach levels of significance in terms of anticholinesterase effect, but, moreover, combinations of different chemical classes were shown to be highly synergistic in their ability to inhibit AChE activity.Biochemistry, 01/2012: chapter 8: pages 205-224; InTech., ISBN: 978-953-51-0076-8