In vitro characterization of cholinesterases in the earthworm Eisenia andrei

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• 作者：Federico Caselli ; Laura Gastaldi ; Naimj Gambi and Elena Fabbri
• 关键词：BW284c51 ; Carbaryl ; Cholinesterase activity ; Earthworm ; Eisenia andrei ; Eserine ; iso-OMPA ; Soil biomonitoring
• 刊名：Comparative Biochemistry and Physiology ; Part C
• 出版年：2006
• 期刊代码：8_15320456
• 类别：pha
• 出版时间：August 2006
• 卷：143
• 期：4
• 页码：416-421
• 文件大小：292 K

摘要

Assessment of pollution impact in soil ecosystems has become a priority and interest has grown concerning the use of invertebrates as sentinel organisms. Inhibition of cholinesterase (ChE) activity has a great potential as a biomarker of pesticide exposure, and we evaluated the ChE kinetic parameters in the earthworm Eisenia andrei in the presence of acetylthiocholine (ASCh), proprionylthiocholine (PSCh) and butyrylthiocholine (BSCh). The highest ChE activity was found in the presence of ASCh and PSCh (42.45 and 49.82 nmol min^{− 1} mg protein^{− 1}, respectively). BSCh was hydrolyzed at a rate of 4.04 nmol min^{− 1} mg protein^{− 1}, but the time course did not reach a plateau under our experimental conditions. K_m values were 0.142 ± 0.006 and 0.183 ± 0.053 mM for ASCh and PSCh, respectively. ASCh and PSCh hydrolysis were significantly inhibited by eserine (IC₅₀ values were 1.44 × 10^{− 8} and 1.20 × 10^{− 8} M, respectively) and by carbaryl (IC₅₀ values of 5.75 × 10^{− 9} and 4.79 × 10^{− 9} M). The presence of different ChEs in tissues from E. andrei was assessed by using selective inhibitors for AChE (BW284c51) and BChE (iso-OMPA). BW284c51 strongly reduced ASCh and PSCh hydrolysis and slightly affected that of BSCh, while iso-OMPA was without effect in all cases.