Biochemical and Enzymatic Characterization of an Acetylcholinesterase From Nereis diversicolor (Annelida, Polychaeta): Comparison With the Cholinesterases of Eisenia fetida (Annelida, Oligochaeta)

Abstract

This study constitutes the first report of a biochemical characterization, involving both substrates and inhibitors and electrophoretic analysis, of a cholinesterase (ChE) from a polychaete annelid (Nereis diversicolor). The ChE of N. diversicolor appears to be an acetylcholinesterase (AChE); i.e., it hydrolyzes acetylthiocholine iodide at a higher rate than other substrates and is inhibited by eserine but not by iso-OMPA. The ChEs of Eisenia fetida are different from that of N. diversicolor and include at least two types of PrChEs. The AChE activity is located principally in the anterior region of the worm (head) in N. diversicolor, whereas the ChE activity of E. fetida is located throughout the body. The electrophoretic characterization of N. diversicolor and E. fetida ChEs showed, respectively, six and two isoforms with disc-PAGE, and three (55,000, 47,000, and 17,000) and five molecular forms (628,000, 301,000, 235,000, 106,000, and 53,800) with PAGGE; substantial activity remained at the top of the PAGGE gel in both species.

Immune defense and biological responses induced by toxics in Annelida

“…Among annelids, ChEs have been characterized in the marine polychaete N. diversicolor (Scaps et al 1996), in two species of terrestrial oligochaete, A. caliginosa (Principato et al 1978(Principato et al , 1979(Principato et al , 1989Kaloustian 1981) and E. fetida (Andersen et al 1978;Stenersen 1980aStenersen , 1980bScaps et al 1996), and in the freshwater hirudinean H. medicinalis (Principato et al 1981(Principato et al , 1983Talesa et al 1995).…”

“…Using 7.5% disc polyacrylamide gel electrophoresis (disc-PAGE), Scaps et al (1996) observed 6 isoforms of AChEs. In N. diversicolor the AChE is represented by two components with similar molecular masses (47 and 55 kDa), a third component with lower molecular mass (18 kDa), and a very important fraction that does not enter the gel (Scaps et al 1996).…”

Environmental applications of earthworm esterases in the agroecosystem

“…35) These two ChEs in E. fetida was later corroborated by Scaps et al, 36) although Andersen et al 37) reported the presence of a ChE activity solely in this earthworm species. Esterase characterization has also been performed with other earthworm species.…”

“…First, selection of earthworm species is critical. Most of the laboratory studies have used Eisenia species to investigate the interaction between ChE activity and OP or CB pesticides, 32,33,[35][36][37][38][39][41][42][43]46,47) and similar studies are comparatively limited with soil-dwelling species. 45) Indeed, sensitivity of ChE activity to pesticides and its recovery rate vary markedly with the species.…”

Earthworm biomarkers of pesticide contamination: Current status and perspectives

“…23) Five different AChE forms corresponding to polymerization of AChE monomers were also isolated by polyacrylamide gradient gel electrophoresis from E. fetida. 46) These studies and other more recent investigations showed that earthworm ChE activity should be referred as a true AChE because of its response to BW284c51 (inhibition) and iso-OMPA (no effect), and its preference for the substrate PrSCh. 39) However, a BChE activity showing some different enzymological properties than those of mammals can be also present in some earthworm species.…”