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AN AUTORADIOGRAPHIC AND HISTOCHEMICAL LOCALIZATION OF SULFATED POLYSACCHARIDES IN EUCHEUMA NUDUM (RHODOPHYTA) 1
Author(s) -
Claire John W.,
Dawes Clinton J.
Publication year - 1976
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1976.tb02859.x
Subject(s) - middle lamella , biology , sulfation , golgi apparatus , polysaccharide , biochemistry , lamella (surface anatomy) , cell wall , endoplasmic reticulum , anatomy
SUMMARY The predominant sulfated polysaccharide, ˛‐carrageenan, was localized in the middle lamella of epidermal, cortical and medullary cells of Eucheumanudum J. Agardh. Autoradiographic studies with 35 SO 4 = indicated that the label was first incorporated in the inner wall and ultimately deposited in the middle lamella of all cells, and in an outer wall layer of the epidermal cells. There was no evidence for cytoplasmic incorporation of the label. The middle lamella stained with alcian blue, was γ‐metachromatic with toluidina blue O and bound diaminobenzidine‐osmium tetroxide. This region was also positive with periodic acid‐Schiff's (PAS) ragent, possibly demonstrating cellulose and/or a nonsulfated precursor of ˛‐carrageenan. A proposed model for extracellular sulfation includes production and secretion of a nonsulfated polygalactan and sulfotransferase enzyme(s) by the golgi apparatus and endoplasmic reticulum, respectively. Free sulfate in the wall would be bound to the precursor polysaccharide, with much of the resulting carrageenan migrating to the middle lamella facilitating mutual cell growth.