Correlation of Ultrastructure and Tensile Properties of a Collagenous Composite Material, the Egg Capsule of the Dogfish, Scyliorhinus spp, a Sophisticated Collagenous Material

Hepworth, David; Gathercole, L.J.; Knight, David P.; Feng, Dian; Vincent, John F.

doi:10.1006/jsbi.1994.1023

Cited by 16 publications

(17 citation statements)

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“…The open meshwork structure of the collagen fibrils (Woodhead-Galloway, I 986) and existence, described above, of transverse channels produced by the registration of the broad (B) and narrow (A) low density bands (Knight & Feng, 1994) may help to explain the high permeability of this material. The binding of acidic glycosaminoglycans to the collagen molecules within these bands revealed by cuprolinic acid staining ) may help to account for the existence of very fine, negatively charged pores.…”

Section: Function Of the Egg Capsule And Related Structuresmentioning

confidence: 97%

“…The secretory granules of the C-and E-zones both contain PO, DO, DOPA and protein(s) exceptionally rich in tyrosine . The C-zone granules, however, do not appear to contain collagen and coalesce to form a varnish-like polymer (Knight & Feng, 1994). The layer L, resembles a phenolic varnish, whereas L, has the structure of cross-linked fibrous composite containing microspherical polymer filler particles (Knight & Feng,I 992).…”

Section: (6) Stabilization Of the Egg Casementioning

confidence: 99%

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Structure and Function of the Salachian Egg Case

1996

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Section: Function Of the Egg Capsule And Related Structuresmentioning

confidence: 97%

Section: (6) Stabilization Of the Egg Casementioning

confidence: 99%

Structure and Function of the Salachian Egg Case

1996

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“…High-angle experiments, carried out by Knight & Hunt (1974) and Rusaouen et al (1976), reported a 2.9-Ð meridional arc typical of a collagen triple helix. Low-angle X-ray di¡raction studies were reported by Gathercole et al (1993), who proposed a unit cell with a b 22.6 nm, c 39.3 nm, and also by Hepworth et al (1994) in which the tensile properties of the egg wall were related to the capsule's multilaminate construction.…”

Section: Introductionmentioning

confidence: 98%

X–ray diffraction analysis of the 3D organization of collagen fibrils in the wall of the dogfish egg case

Knupp

Squire

1998

Proc. R. Soc. Lond. B

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The wall of the egg case of the dog¢sh, Scyliorhinus canicula, contains a network-forming collagen assembled into a regular three-dimensional (3D) structure. It accomplishes supportive, protective and ¢ltering functions for the embryo contained within it. The collagen molecules in the egg case are organized into a body-centred unit cell of dimensions (mean AE s.d.) (11.6 AE 1.0) nm Â (11.6 AE 1.0) nm Â (81.6 AE 3.2) nm, which belongs to the I422 space group. At a higher hierarchical level, the collagen molecules assemble into parallel arrays of ¢brils, ca. 100 nm in diameter, which aggregate to form laminae ca. 0.5 mm thick. These laminae are organized into a plywood-like structure and account for 98% of the thickness of the wall of the egg case. X-ray di¡raction patterns of the wall of the egg case were taken along mutually perpendicular directions, one being perpendicular to the surface of the egg case. Three di¡erent kinds of di¡raction pattern were observed. One of the patterns was characteristic of an X-ray direction perpendicular to the laminae in the egg case (along the x-direction). The two other patterns were obtained with the X-rays directed parallel to the plane of the laminae, either along the capsule long axis (z) or perpendicular to this ( y). These two patterns were observed interchangeably in either of the xor y-directions depending on the specimen. The di¡raction patterns were analysed and interpreted taking into consideration the 3D electron microscope data of the egg case. The results con¢rm and extend previous ¢ndings from transmission electron microscopy and low-angle X-ray di¡raction and they suggest that there is only one major type of ordered collagen arrangement in the wall of the egg case.

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“…The structures of the collagen assemblies in the egg case of the dogfish S. canicula have been studied previously using electron microscopy and 3D reconstruction [3,4,8,10,[13][14][15][16][17] as well as X-ray diffraction [9,18,19]. From these studies, the collagen forming the bulk of egg case appears to assemble in layers of variable thickness, in which oriented quasi-crystalline fibers are laid down in approximately orthogonal directions systematically from one layer to an other [1,2,20].…”

Section: Introductionmentioning

confidence: 99%