All ETDs from UAB

Advisory Committee Chair

Stephen A Watts

Advisory Committee Members

Leo Pezzementi

R Douglas Watson

Document Type


Date of Award


Degree Name by School

Master of Science (MS) College of Arts and Sciences


Acetylcholinesterase (AChE) in a deuterostome invertebrate, the echinoid Lytechinus variegatus, has been characterized. Kinetic parameters Vmax, Km, Kss, and b were 453 ± 183 μM ATCh hydrolyzed/minute, 185 ± 11 μM, 308 ± 100 mM, and 0.2, respectively for the substrate acetylthiocholine (ATCh) and 3.1 ± 1.2 μM BTCh hydrolyzed/minute, 654 ± 424 μM, 36 ± 31 mM, and 0.6, respectively for substrate butyrylthiocholine (BTCh). Pharmacologic analyses were performed with four inhibitors of cholinesterases, physostigmine, BW284c51, ethopropazine, and iso-OMPA, and yielded IC50 values of 106 ± 4 nM, 718 ± 118 nM, 2.57 ± 0.6 mM, and > 0.0300 M, respectively. Both kinetic and pharmacologic results confirmed the existence of AChE in larval L. variegatus. Molecular forms were determined by velocity sedimentation on sucrose gradients. Dimeric (G2) and tetrameric (G4) globular forms were found to be present in L. variegatus larvae. Activity of AChE increased significantly as larvae progressed in development from embryos to 8-arm larvae. Acetylcholinesterase activity of F1 larvae derived from sea urchins collected from wild populations and of F1 larvae derived from sea urchins cultured in the laboratory and fed two different diets suggest that the nutritional and/or environmental history of the adult sea urchin affect the developmental progression of AChE activity in the F1 offspring. Acetylcholinesterase activity was detected in wild adult sea urchin tissues. Activity was significantly higher in iii the gonad than the esophagus, stomach, and intestine. The functional consequences of differential AChE activities among tissues are unknown.



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