A Method for Fast Assessment of OP/CB Exposure in the Japanese Quail (Coturnix coturnix japonica) Using Combined Esterases Enzyme Activity as Biomarkers

Abstract

The aims of this study were to investigate the presence of different esterase activities in plasma and liver for Japanese quail and to combine determination of both carboxylesterase and cholinesterase as biochemical biomarker in order to identify the effects of carbamate and organophosphate compounds exposure. Carboxylesterase exhibits larger sensitivity to carbamate and organophosphate compounds than to cholinesterase and is present at higher levels. This permitted nature and distribution of carboxylesterase or cholinesterase to be measured. One predominant toxicological form of enzyme level constant in its patterns of motivation and inhibition with cholinesterase was identified in plasma with an apparent Michaelis constant for butyrylthiocholine iodide of 0.394 mM. Carboxylesterase activity in liver was considered by its preferential hydrolysis of the S-phenyl thioacetate. A concentration dependent decrease of carboxylesterase and cholinesterase has demonstrated during in vitro incubation of malathion, parathion, and trichlorfon in the range 0.125–2 mM, while with methomyl was in the range 0.25–4 mM. When quail (n = 15) was exposed orally for 48 h to concentrations of carbamate or organophosphate compounds of 3–200 mg/kg, the percentage inhibition of cholinesterase was in each case larger than that of carboxylesterase and reached statistical significance (P < 0.05) at lower concentrations.

Experimental Measurements for the Effect of Dilution Procedure in Blood Esterases as Animals Biomarker for Exposure to OP Compounds

“…In summary, this study used an in vitro assay to measure detoxification by CbE and ChE of a malathion compound (Table 3). This screening method could be useful for predicting the degree of esterase detoxification, and this information could be useful in assessment of animal variability due to differences in esterase activities [2]. Dilution 1 : 5 was observed to have the highest specificity constant ( k cat / K m ), and the K m and k cat values were 176  μ M and 16,765 s −1 , respectively, for PSA ester, while dilution 1 : 15 had the lowest specificity constant ( k cat / K m ), and the K m and k cat values were 943  μ M and 1154 s −1 , respectively, for AcTChI ester.…”

“…Plasma was separated by centrifugation at 5000 g for 10 min [2]. To obtain serum, blood samples were allowed to clot for at least 2 h at 25°C, after which they were centrifuged at 5000 g for 10 min.…”

“…Then the data were fitted with nonlinear regression analysis using a single exponential decay by SigmaPlot 11 (Systat software, Inc.). The Michaelis constant ( K m ) and turnover number ( k cat ) were determined according to Abass [2]. …”

“…An esterase is a hydrolase enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis [ 1 , 2 ]. Carboxylesterase (CbE)/cholinesterase (ChE) family members are under esterase enzyme and are responsible for controlling the nerve impulse, detoxification, and various developmental functions and are a major target of pesticides and chemical warfare agents [ 2 – 4 ]. Comparative structural analysis of these enzymes is thus important [ 2 , 5 , 6 ].…”

Efeito protetor das esterases em tilápias do Nilo (Oreochromis niloticus) expostas ao organofosforado Masoten®

“…No entanto, isso pode variar de acordo com a espécie estudada. De fato, Abass 43 , ao estudar esterases de Coturnix coturnix, japonica, observou que a atividade de butirilcolinesterase no plasma é cerca de 10 vezes maior do que a de CarbE. O perfil de inibição de esterases frente ao trichlorfon, porém, é semelhante ao encontrado nas tilápias, em que as BChE são mais sensíveis do que as CarbE.…”