Spatial organization of collagen in annelid cuticle: order and defects
- 1 January 1988
- journal article
- research article
- Published by Wiley in Biology of the Cell
- Vol. 62 (1), 17-31
- https://doi.org/10.1016/0248-4900(88)90040-8
Abstract
The epidermis of Paralvinella grasslei (Polychaete, Annelida) is covered by an extracellular matrix, the cuticle, mainly composed as in other annelids of superimposed layers of non-striated collagen fibrils. The collagen fibrils of annelid cuticle are shown to be composed of parallel and sinuous microfibrils (thin sections and freeze-fracture replicas). The 3-dimensional organization of collagen is characterized by 2 different types of geometrical order: (a) Fibrils form a quasiorthogonal network, whose structure is comparable to that of a "plywood"; (b) Fibrils are helical, and goniometric studies show that microfibrils present a definite order within each fibril, which is termed "cylindrical twist". These 2 characteristics are those which have recently been evidenced in "blue phases", i.e., liquid crystals which are closely related to cholesteric liquid crystalline phases. Non-fluid analogues of cholesteric liquids are widespread among invertebrate cuticles and the presence of blue phase analogues suggests that a self-assembly mechanism is involved in cuticle morphogenesis, which is derived from that governing blue phase growth. The cuticular network presents local rearrangements of fibrils called "defects", despite the fact that they are elaborate structures which trigonal and pentagonal singularities. Branched fibrils are regularly observed. We discuss the involvement of these pattern disruptions in the cuticle growth process.Keywords
This publication has 13 references indexed in Scilit:
- Nereis cuticle collagen: Relationship of fiber ultrastructure to biochemical and biophysical propertiesJournal of Ultrastructure Research, 1981
- DIFFERENCES IN THE MICROFIBRILLAR ARRANGEMENT OF COLLAGEN FIBRILS - DISTRIBUTION AND POSSIBLE SIGNIFICANCE1981
- Collagen fibrils with straight and helicoidal microfibrils: a` freeze-fracture and thin-section studyJournal of Ultrastructure Research, 1979
- Invertebrate CollagensScience, 1978
- Relationships between fibronectin (LETS protein) and actinCell, 1978
- Nereis cuticle collagen. Isolation and properties of a large fragment resistant to proteolysis by bacterial collagenase.Journal of Biological Chemistry, 1977
- Freeze-fracture replication and surface sublimation of frozen collagen fibrilsJournal of Cell Science, 1977
- Collagen structure: Evidence for a helical organization of the collagen fibrilJournal of Ultrastructure Research, 1977
- Collagen fibrillogenesis: intermediate aggregates and suprafibrillar order.Proceedings of the National Academy of Sciences, 1976
- Collagenous and other organizations in mature annelid cuticle and epidermisJournal of Morphology, 1976