Meeting Abstract

P1.148  Friday, Jan. 4  Enzyme Activity in Early Life Stages of Planktotrophic Slipper Snails (Gastropoda: Calyptraeidae) STARR, M. J.*; COLLIN, R.; Smithsonian Tropical Research Institute; Smithsonian Tropical Research Institute mjs3424@louisiana.edu

Enzymatic activities of 19 intracellular enzymes were studied in four planktotrophic species of calyptraeid gastropods (Crepidula incurva, Crepidula cf. marginalis, Crucibulum spinosum, and Bostrycapulus calyptraeformis). Standardized embryo homogenates were assayed for 19 enzymes at four embryonic stages and once after hatching and exposure to exogenous food. Eight enzymes showed significant species differences. When differences were observed among species, generally C. incurva and C. spinosum were different. Enzyme activity in C. incurva was significantly higher than the other species for three enzymes and lower for three. For C. spinosum activity was higher for five and lower for one enzyme. Differences among developmental stages varied for the enzymes assayed. Alkaline phosphatase, α-fucosidase, N-acetyl-β-glucosaminidase, and Esterase Lipase (C8) increased significantly throughout development. Two enzymes increase significantly early in development then remained constant (Acid phosphatase and Naphthol-AS-BI-phosphohydrolase). β-glucosidase increased significantly after hatching and after exposure to isochrysis. Two enzymes showed high activity throughout development (Leucine arylamidase and Esterase (C4)). Three enzymes peaked in mid development (α-mannosidase, Cystine arylamidase, α-chymotrypsin). Seven enzymes showed little (β-galactosidase, β-glucuronidase, Caline arylamidase, Lipase (C14)) or no (Trypsin, α-galactosidase, and α-glucosidase) activity and no significant changes during development. Few interactions between species and stage were observed, suggesting that planktotrophs all show the same general patterns. This study is a useful baseline against which to compare enzyme expression in other modes of development.