HISTOCHEMICAL ANALYSIS OF GLYCOPROTEINS IN THE EPIDERMAL MUCOUS CELLSAND SACCIFORM CELLS OF AN INDIAN SWAMP EEL MONOPTERUS-CUCHIA (HAMILTON) (SYNBRANCHIFORMES, PISCES)

In the epidermis of the fish Monopterus cuchia, the mucous and saccifo rm cells have been studied by means of a series of histochemical proce dures for localizing and characterizing glycoprotein (GP) classes invo lving oxidizable vicinal diols, O-acyl sugars, O-sulfate esters and si alic acid residues without or with O-acyl substituents. GPs secreted b y these gland cells belong to three general categories. These are (i) GPs synthesized by type A mucous cells and predominantly containing O- sulfate esters and small amounts oxidizable vicinal diols, O-acyl suga rs and sialic acid residues without or with O-acyl substitution at C7, C8 (or which are di- or tri- substituted) or C9, (ii) GPs elaborated by type B mucous cells primarily with O-sulfate esters, and relatively small amounts of oxidizable vicinal diols and sialic acid residues pr edominantly without or with O-acyl substitution at C7 as well, and (ii i) GPs secreted by sacciform cells with exceedingly small amounts of o xidizable vicinal diols and O-sulfate esters. Mixed GPs on the surface mucous layer are considered to play an important function for lubrica tion, adherence of micro-organisms and inhibition of their invasion an d proliferation in the epidermis, hydration and viscoelastic propertie s, in relation to an adaptation for the maintenance of this semi-terri strial fish frequently exposed to semi-arid conditions.