title: Histology and lectin-binding patterns in the skin of the terrestrial horned frog Ceratophrys ornata.
abstract: The terrestrial horned frog, Ceratophrys ornata, lives on a wet substratum and absorbs water through the ventral epidermis; water is lost by evaporation from the dorsal skin. Thus, this species may be useful as a model for determining whether or not skin histology and lectin-binding patterns, indicative of glycoconjugates, are related to skin functions such as osmoregulation and water balance. With this in mind, a histological and lectin-histochemical study was carried out on dorsal and ventral skin of aquatic tadpoles and of a young terrestrial frog of C. ornata. Sections of skin were stained with various dyes to demonstrate general histological features and with two horseradish peroxidase (HRP)-conjugated lectins, Ulex europaeus agglutinin (UEA 1) and soybean agglutinin (SBA) which bind to specific terminal sugar residues of glycoconjugates, namely L-fucose and N-acetyl-D-galactosamine or D-galactose, respectively. In early stage tadpoles both lectin-binding patterns were similar in the bilaminar epidermis of dorsal and ventral skin (i.e., each lectin stained the apical cell layer). However, metamorphic changes resulted in a young frog with typical adult-type skin composed of a stratified squamous epidermis and three distinct types of glands containing glycoconjugates in their secretions. Strikingly different lectin-binding patterns were evident in the epidermis from dorsal and ventral regions of the body. The epidermis from the dorsal region was stained by both lectins; in contrast, that from the ventral region, although stained strongly by HRP-SBA, did not react with HRP-UEA 1, indicating that few, if any, fucose residues were present in the ventral epidermis.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA.
authors.forename: E E
authors.initials: EE
authors.lastname: Faszewski
authors.forename: J C
authors.initials: JC
authors.lastname: Kaltenbach
mesh_terms: D000818:Animals; D001001:Anura / Q000033:anatomy & histology*; D007814:Larva / Q000166:cytology; D037102:Lectins; D012867:Skin / Q000166:cytology* / Q000378:metabolism
chemical_list: D037102:Lectins