Fine structure of the abdominal epidermis of the adult mudpuppy, Necturus maculosus (Rafinesque)

Abstract

The ventral epidermis of adult Necturus maculosus has been studied using electron and light microscopy. Many larval characteristics of amphibian epidermal structure are retained in adult Necturus. The epidermis is a stratified epithelium consisting of four cell layers and five cell types. Major differences compared with other adult amphibians are: the absence of a well defined moulting cycle together with an apparently diminished synthetic and mitotic activity in the stratum germinativum; an outermost cell layer (stratum mucosum) that is unkeratinized and appears to synthesize a mucous layer; and numerous large club-shaped Leydig cells which span the epidermis between the cells of the stratum germinativum and stratum mucosum. The apical region of the stratum granulosum and stratum mucosum cells shows evidence of extensive synthesis. The stratum mucosum appears to be involved in the secretion of vesicular contents onto the outermost surface of the epithelium. The external surfaces of the stratum mucosum cells possess numerous microridges which are supported by an intricate network of cytofilaments in the apical region of these cells. The significance of these features is discussed in relation to the physiology and ecology of this species.

Microridges in Cyprinus carpio scale epidermis

“…Similar protruding structures have also been identified in the epithelial enveloping layer (EVL) of gastrulating zebrafish embryos (Crawford, Henry, Clason, Becker, & Hille, 2003;Zalik, Lewandowski, Kam, & Geiger, 1999) and the surface of unfertilized Brachydanio eggs (Hart & Donovan, 1983). Furthermore microridges are not restricted to fish and are indeed found in the epithelial tissue of a wide range of animal species including, for example, frog epidermis (Goniakowska-Witalinska & Kubiczek, 1998;Saito & Itoh, 1992), mudpuppy (Lindinger, 1984), human epidermal lamina densa (Mihara, Miura, Suyama, & Shimao, 1992) and cornea (Versura, Bonvicini, Caramazza, & Laschi, 1985), unfertilized eggs of the sea cucumber (Holland, 1981) and rhesus monkey oesophagus (Andrews, 1976). Furthermore microridges are not restricted to fish and are indeed found in the epithelial tissue of a wide range of animal species including, for example, frog epidermis (Goniakowska-Witalinska & Kubiczek, 1998;Saito & Itoh, 1992), mudpuppy (Lindinger, 1984), human epidermal lamina densa (Mihara, Miura, Suyama, & Shimao, 1992) and cornea (Versura, Bonvicini, Caramazza, & Laschi, 1985), unfertilized eggs of the sea cucumber (Holland, 1981) and rhesus monkey oesophagus (Andrews, 1976).…”

“…Microridges cover the surface of the maxillary barbel of zebrafish, an integumentary sense organ of the adult fish (LeClair & Topczewski, 2010). Furthermore microridges are not restricted to fish and are indeed found in the epithelial tissue of a wide range of animal species including, for example, frog epidermis (Goniakowska-Witalinska & Kubiczek, 1998;Saito & Itoh, 1992), mudpuppy (Lindinger, 1984), human epidermal lamina densa (Mihara, Miura, Suyama, & Shimao, 1992) and cornea (Versura, Bonvicini, Caramazza, & Laschi, 1985), unfertilized eggs of the sea cucumber (Holland, 1981) and rhesus monkey oesophagus (Andrews, 1976). Microridges have also been observed in vitro in the A6 kidney cell line (Gorelik et al, 2003) and cultured melanoma cells (Poole & Muller, 2005).…”

Cellular diversity in the epidermis of Raja clavata (Chondrichthyes)

“…This condition can be most closely compared with that in Latimeria chalumnae (Whitear, 1977); adult neotenous urodeles, also, accumulate a layer of secretory vesicles in the subapical region of the super®cial epithelial cells (Whitear, pers. obs., Fa Èhrmann, 1971;Lindinger, 1984). Connections between epithelial cells, by tight junctions at the surface, and desmosomes below, and the general cytology of the epithelial cells, are similar in the ray and in a generalized teleost type.…”

Morphology and ultrastructure of the gills in two Urodela species:Salamandrina terdigitataandTriturus carnifex

“…They are often assumed to be mucussecreting cells: this hypothesis was supported by several authors (Langerhans 1873;Leydig 1876;Seeger 1933) and confirmed most recently by several other researches (Lindiger 1984;Jarial 1989).…”