Localization and Identification of Mucoprotein in the Skin and Gills Epidermal Mucous cells of Cynoglossus semifasciatus

Localization and characterization of skin and gill epidermal mucoproteins (SEM, GEM) in the mucous cells located in the gills of the fish Cyanoglossus arel were investigated. Using histological procedures pavement cells are the most abundant type of cell on both primary and secondary lamellae and there are a great number of mucous and chloride cells between them. Histochemical characteristics that included methods for localization and characterizat ion of glycoproteins (GPs), showed no differences between the mucous cell contents of the primary and secondary lamellae. In the tongue sole skin, four morphologically distinct layers were identified: cuticle, epidermis, dermis and hypodermis. Neutral mucosubstances and/or glycoconjugates were observed in the epidermis, dermis and hypodermis of C.semif asciatus skin. Proteins rich in different amino acids, such as arginine and cysteine, reacted negatively or weakly positive in the epidermis, dermis and hypodermis. Blue at pH 2.5. When Alcian Blue pH 2.5–PAS reaction was performed, most mucous cells were stained blue (carboxylated mucins) and some mucocytes stained purple, indicating a combination of neutral and acid mucins. Proteins rich in cysteine-bound sulphydryl (-SH-) and cystine disulphide (-S-S-) g roups were strongly detected in epidermal mucous cells, where as lysine, tyrosine and arginine containing proteins showed very weak staining in epidermal mucous cells. Protein reactions were strongly positive in the pillar cells, except for those rich in tryptophan. It is concluded from this study that cytohistochemical features of the tongue sole skin and Gill may serve as structures in natural systems to monitor or detect environmental stress responses at the histological level and histochemical level. The GPs were identified with (a) oxidizab le vecinal dio ls; (b) sialic acids; (c) carboxyl groups and (d) sulphate groups. The distribution pattern of the mucous was identical in the primary and secondary lamellae. This work clearly demonstrates the heterogeneity of the mucous cell glycoconjugates, which could be involved in various functions, such as lubrication, protection, inhibit ion in microorganisms and a role in the regulation and diffusion.