Lectin-Binding Differences on Hemocytes of Two Geographic Strains of the American Oyster, Crassostrea virginica

Abstract

The saccharidal constituents of the surfaces of hemocytes of the American oyster, Crassostrea virginica, from Apalachicola Bay, Florida, and Galveston Bay, Texas, were determined by employing eight lectins with known sugar specificities (Con A, Tetragonolobus purpureas, Limulus polyphemus, Dilichos biflorus, Sambucas nigra, Glycine max, Triticum vulgaris, and Lathyrus odoratus). Known inhibiting sugar residues were used to inhibit clumping of lectin-treated oyster hemocytes. As a result, the following saccharides were demonstrated to occur on oyster hemocytes: N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, methyl-a-D-mannopyranoside, D(+)-glucose, sucrose, D(+)mannose, a-methyl-D-galactoside, -D(-)-fructose, L(-)-fucose, N-acetylneuraminic acid, and D(+)-galactose. In addition, D-glucuronic acid occurred only on oyster cells from Apalachicola Bay and an unidentified sugar that binds to the L. odoratus lectin that is neither D(+)-glucose nor D(+)-mannose, the usual inhibiting sugars, occurs on hemocytes from both Apalachicola and Galveston Bays. Quantitative and qualitative differences in the saccharidal constituents on the surfaces of hemocytes from oysters from the two collecting sites are attributed to strain differences. Naturally occurring lectins in invertebrates have been repeatedly proposed, among other functions, to play a role in the recognition of self from nonself (Anderson & Good, 1976; Cheng, 1984; Cheng et al., 1984; Renwrantz, 1981). These proteins or glycoproteins include binding sites that recognize specific sugar residues. In order to identify the carbohydrates, which are the primary determinants of cellular identity of many cells (Gaveriaux & Loor, 1987), and by so doing increase our understanding of lectin-mediated attachment or nonattachment of biotic invaders, we have tested the effects of selected lectins with known saccharidal specificities on hemocytes of the American oyster, Crassostrea virginica (Gmelin). MATERIALS AND METHODS Oysters. The oysters employed in this study originated from two sources: Apalachicola Bay, Florida, and Galveston Bay, Texas, U.S.A. All were harvested during the last week in February through the second week in April 1992. All oysters were held in the laboratory at 3?C in 15% seawater until 1 h prior to bleeding. None was held for more than three days. i The outstanding technical assistance by Ms. Janet M. Barto is gratefully acknowledged. This research was supported by a grant (NA16FLO408-01) from the National Marine Fisheries Service, U.S. Department of Commerce. TRANS. AM. MICROSC. Soc., 112(2): 151-157. 1993. ? Copyright, 1993, by the American Microscopical Society, Inc. This content downloaded from 207.46.13.124 on Wed, 22 Jun 2016 05:21:35 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC.