A butyrylcholinesterase in the early development of the brine shrimp (Artemia salina) larvae: a target for phthalate ester embryotoxicity?

R.A. Acey, S. Bailey, P. Healy, C. Jo, T.F. Unger, R.A. Hudson-2002

Biochemical and Biophysical Research Communications, 299(4): 659-662 (from Current Contents- via ISI Current Contents)

Abstract:
The phthalate ester insensitive blue-green algae (Synechococcus lividus) were used as a food source to extend the survival of synchronously hatched brine shrimp (Artemia salina) larvae allowing measurement of a reduced toxic response to phthalate esters at late post-hatching stages of development. The maximum acute toxicity due to di-n-butyl phthalate (DNBP) correlated with the expression of a phthalate ester-hydrolyzing enzyme. The purified enzyme was identified as a butyrylcholinesterase due to its rapid inactivation by low concentrations (10(-7) M) of diisopropyl fluorophosphate and inhibition by physostigmine (IC50 = 6 x 10(-7) M) and tetraisopropylpyrophosphoramide (I-OMPA, IC50 = 5 x 10(-6) M) but not by BW284c5. Apparently competition of the phthalates with the endogenous substrates of the enzyme led to development-dependent toxicity.

(California State University, Long Beach, Dept. Chem. & Biochem., Long Beach CA 90840, USA, e-mail: racey@csulb.edu)

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