Glycoconjugate localization in larval and adult skin of the bullfrog, Rana catesbeiana: A lectin histochemical study

Abstract

This study investigates whether or not the distribution of specific glycoconjugates within the skin is related to the regulation of water balance in the aquatic larvae and semiaquatic adults of the bullfrog, Rana catesbeiana. A lectin histochemical study was carried out on paraffin sections of dorsal and ventral skin from tadpoles in representative stages as well as from adult frogs. Sections were stained with the following horseradish peroxidase (HRP)-conjugated lectins, which bind to specific terminal sugar residues of glycoconjugates: UEA 1 for alpha-L-fucose, SBA for N-acetyl-D-galactosamine, WGA for N-acetyl-B-D-glucosamine, and PNA for beta-galactose. Results indicate that lectins serve as markers for specific skin components (e.g., a second ground substance layer within the dermis was revealed by positive UEA 1 staining). Moreover, each lectin has a specific binding pattern that is similar in dorsal and ventral skin; the larval patterns change as the skin undergoes extensive histological and physiological remodeling during metamorphic climax. These findings enhance our understanding of glycoconjugates and their relationship to skin structure and function-in particular, to the regulation of water balance in R. catesbeiana.

Metamorphic changes in localization of sugars in skin of the leopard frog, Rana pipiens

“…In Rana pipiens, histological features of larval and adult skin are well established (e.g., Bovbjerg, 1963;Fox, 1984Fox, , 1985Mills and Prum, 1984); however, to our knowledge, lectin binding patterns, indicative of cutaneous glycoconjugates, have not been resolved in skin of this species. Yet, numerous studies on lectin binding patterns have been carried out on adult skin of other ranids as well as of aquatic and terrestrial species (review in Kaltenbach et al, 2004). In preliminary research, we found positive lectin staining in larval and adult skin of R. pipiens in all body regions (Kaltenbach et al, 1991;Faszewski and Kaltenbach, 2006); these findings are in contrast to the absence of staining in adult ventral skin of this species as reported by Zaccone et al (1999).…”

Glycoconjugate histochemistry of mucous glands in the skin of metamorphosing Bufo viridis

“…These results indicate that conical cells express mainly mannose, galactose and partially α(2→3) linked sialic acid bearing glycoconjugates. More recently, it was stated that the secretory cells of the mucous glands express α-fucose and α-galactose in Bufo ictericus (de Brito Gitirana et al 2007) and β-galactose in Rana catesbeiana skin (Kaltenbach et al 2004). These different results may be derived from interspecific diversity.…”

“…These different results may be derived from interspecific diversity. On the other hand, there might be a discrepancy in glycoconjugate contents between adult and developing mucous glands; these also could be related to season, habitat and body region from which the skin samples were obtained, as well as the size and gender (Kaltenbach et al 2004). …”

“…It is comprised of two major parts: a mucus-covered epidermis and underlying dermis. During metamorphosis, distinct structural changes occur in the skin paralleled by changes in its functional properties (Takada 1985;Fox 1986), for example, mucous glands develop and dorsal skin of body transforms to adult skin, whereas tail skin disappears by tail resorption at metamorphic climax stage (Kaltenbach et al 2004;Kinoshita et al 2005). Cutaneous mucus produced by intradermal mucous glands protects amphibians from excessive water loss or gain, acts as a barrier that protects from bacterial and fungal infections and minimizes mechanical damage to the skin out of water (Clarke 1997).…”

Exfoliation of the Epidermal cells and Defecation by Amphibian Larvae in Response to Coelomic Fluid and Lysenin from the Earthworm Eisenia foetida

“…It is known that glycolipids prevent the access of lysenin to SM (7). Kaltenbach et al (9) examined histochemically changes in glycoconjugates in larval skin at various developmental stages of the bullfrog. The earliest stage they examined was stage V (27), which is equivalent to stage 36 (the stage after the exfoliation period) in Bufo, as judged from the morphological characteristics of the hind-limb bud.…”