Collagen Fibrils, Spongin, Matrix Substances
Collagen fibrillogenesis is a universal process in sponges and in some species represents the secretory process while in others it is overshadowed by mineralization. In some ceractinomorph demosponges, colossal quantities of collagen are elaborated and requirements for precursors are undoubtedly very high. Although a major process, fibrillogenesis is a relatively slow one that presents challenging problems experimentally as does the resistance of sponge collagens to enzymatic degradation. Sponges also elaborate glycoproteins, and proteoglycans, and evidence is accumulating that some of these are associated with cell surfaces and collagen fibrils in addition to their presumed role in forming the intercellular ground substance. Some aspects of these substances as well as sponge lectins are dealt with further in Chapter Nine. Collagen has been best studied and an outstanding monograph on sponge collagens has recently appeared (Garrone, 1978). There is a wealth of information in this volume, including some original data not reported elsewhere, and reference to it is mandatory for those requiring complete details.
KeywordsCollagen Fibril Rough Endoplasmic Reticulum Sponge Collagen Sponge Tissue Matrix Substance
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