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The Scientific World Journal
Volume 2012 (2012), Article ID 960159, 12 pages
Research Article

Ultrastructure and Glycoconjugate Pattern of the Foot Epithelium of the Abalone Haliotis tuberculata (Linnaeus, 1758) (Gastropoda, Haliotidae)

1Instituto Español de Oceanografía, Centro Oceanográfico de Vigo, Apdo. 1552, 36200 Vigo, Spain
2Department of Biochemistry, Genetics and Immunology, University of Vigo, 36310 Vigo, Spain
3Department of Functional Biology and Health Science, University of Vigo, 36310 Vigo, Spain

Received 29 October 2011; Accepted 21 December 2011

Academic Editors: M. Gotte and S. Hong

Copyright © 2012 I. Bravo Portela et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The foot epithelium of the gastropod Haliotis tuberculata is studied by light and electron microscopy in order to contribute to the understanding of the anatomy and functional morphology of the mollusks integument. Study of the external surface by scanning electron microscopy reveals that the side foot epithelium is characterized by a microvillus border with a very scant presence of small ciliary tufts, but the sole foot epithelium bears a dense field of long cilia. Ultrastructural examination by transmission electron microscopy of the side epithelial cells shows deeply pigmented cells with high electron-dense granular content which are not observed in the epithelial sole cells. Along the pedal epithelium, seven types of secretory cells are present; furthermore, two types of subepithelial glands are located just in the sole foot. The presence and composition of glycoconjugates in the secretory cells and subepithelial glands are analyzed by conventional and lectin histochemistry. Subepithelial glands contain mainly N-glycoproteins rich in fucose and mannose whereas secretory cells present mostly acidic sulphated glycoconjugates such as glycosaminoglycans and mucins, which are rich in galactose, N-acetyl-galactosamine, and N-acetyl-glucosamine. No sialic acid is present in the foot epithelium.