Demuynck S

References (2)

Title : Effects of organophosphate and carbamate pesticides on acetylcholinesterase and choline acetyltransferase activities of the polychaete Nereis diversicolor - Scaps_1997_Arch.Environ.Contam.Toxicol_33_203
Author(s) : Scaps P , Demuynck S , Descamps M , Dhainaut A
Ref : Archives of Environmental Contamination & Toxicology , 33 :203 , 1997
Abstract : A toxicity test for organophosphates (OP) and carbamates (C) was improved with the adult ragworm Nereis diversicolor. Animals were maintained in U-shaped glass tubes of 4-mm inner diameter fixed vertically on a plastic plate and placed in glass aquaria. Each tank was covered with glass in order to reduce evaporation and heat dissipation. Temperature varied between 15 and 16 degrees C and salinity was constant (34 per thousand) during the entire length of the experiment. Experiments were performed with a fixed day length of 12 h and seawater was gently aerated. The maintenance system allowed the administration of OP and C compounds via the seawater. An acclimatization period of 48 h was not sufficient to accomodate worms to their artificial burrows; accordingly, we chose to acclimate worms for a week before beginning the exposure. Choline acetyltransferase (ChAT) activity was very low and was not significantly modified by two OP compounds: malathion and parathion-ethyl. ChAT is not a target for these pesticides and should not be used for future studies about OP and C toxicity. On the other hand, inhibitory effects on acetylcholinesterase (AChE) activity were determined at concentrations of 10(-6) M for three OP compounds-malathion, parathion-ethyl, and phosalone-and a carbamate pesticide-carbaryl. We measured only short-term effects and no cumulative effect was determined, the maximum percentage of AChE activity inhibition being between 2 (carbaryl) and 7 (OP compounds) days after exposure and then remaining stable. Mortality occured only after a period of intoxication of 14 days. N diversicolor, which can be easily maintained at the laboratory, seems to be a good candidate for future laboratory studies to test the toxicity of other pollutants.
ESTHER : Scaps_1997_Arch.Environ.Contam.Toxicol_33_203
PubMedSearch : Scaps_1997_Arch.Environ.Contam.Toxicol_33_203
PubMedID: 9294250

Title : Biochemical and Enzymatic Characterization of an Acetylcholinesterase From Nereis diversicolor (Annelida, Polychaeta): Comparison With the Cholinesterases of Eisenia fetida (Annelida, Oligochaeta) - Scaps_1996_Biological.Bulletin_190_396
Author(s) : Scaps P , Demuynck S , Descamps M , Dhainaut A
Ref : Biol Bull , 190 :396 , 1996
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.
ESTHER : Scaps_1996_Biological.Bulletin_190_396
PubMedSearch : Scaps_1996_Biological.Bulletin_190_396
PubMedID: 29227704