Quantitative electron microscope observations of the collagen fibrils in rat-tail tendon

Biopolymers ◽  
1977 ◽  
Vol 16 (5) ◽  
pp. 1015-1031 ◽  
Author(s):  
D. A. D. Parry ◽  
A. S. Craig
Keyword(s):  
Electron Microscope ◽  
Collagen Fibrils ◽  
Tail Tendon ◽  
Rat Tail

Platelet Adhesion to Native Collagens Involves Proteoglycans and May Be a Two-Step Process

1987 ◽  
Vol 58 (02) ◽  
pp. 786-789 ◽  
Author(s):  
O Behnke
Keyword(s):  
Electron Microscope ◽  
Platelet Adhesion ◽  
Close Contact ◽  
Blood Platelets ◽  
Collagen Fibrils ◽  
Platelet Membrane ◽  
Step Process ◽  
Rat Blood ◽  
Wide Gap ◽  
Rat Tail

SummaryAdhesion of rat blood platelets to native rat tail collagen fibrils was studied in the electron microscope under conditions that preserved collagen-associated proteoglycans (CAPG). The CAPG molecules were aligned in chain-like configurations that encircled the fibrils with a 65 nm period; they appeared to coat the fibrils completely and extended 60-100 nm away from the fibril. The initial platelet-fibril contact occurred between the platelet glycocalyx and the CAPG of the fibrils i.e. between two surfaces with net-negative charges. When close contact was established between the fibril surface proper and the platelet membrane, CAPG were not identified in the area of contact, and the collagen-platelet distance was reduced to a ~10-12 nm wide gap traversed by delicate links in register with fibril periodicities.

An Estimate of the Mean Length of Collagen Fibrils in Rat Tail-Tendon as a Function of age

1989 ◽  
Vol 19 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Alan S. Craig ◽  
Mervyn J. Birtles ◽  
James F. Conway ◽  
David A.D. Parry
Keyword(s):  
Collagen Fibrils ◽  
The Mean ◽  
Tail Tendon ◽  
Rat Tail

Interstitial exclusion of macromolecules studied by graded centrifugation of rat tail tendon

1997 ◽  
Vol 273 (6) ◽  
pp. H2794-H2803 ◽  
Author(s):  
Knut Aukland ◽  
Helge Wiig ◽  
Olav Tenstad ◽  
Eugene M. Renkin
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
Colloid Osmotic Pressure ◽  
Collagen Fibrils ◽  
Free Fluid ◽  
Mechanical Compression ◽  
The Third ◽  
Tail Tendon ◽  
Molecular Sieving ◽  
Rat Tail

Mechanical compression of cartilage and tendon has been shown to expel fluid both from collagen fibrils and from the extrafibrillar space. As reported previously, albumin (Alb) concentration and colloid osmotic pressure in tendon fluid (TF) expelled by repeated centrifugations fell progressively at increasing centrifugation force (G = 600, 2,400, and 13,100), suggesting either molecular sieving in compressed tendon or mobilization of protein-free (excluded) fluid. The present experiments, including analysis of 51Cr-EDTA, aprotinin (Ap), Alb, immunoglobulin G (IgG), and hyaluronan (hyaluronic acid; HA) with molecular weight (MW) ranging from 341 to 5 × 106, strongly favored the exclusion hypothesis; the fraction of Alb, IgG, and HA-free fluid (excluded) was already 0.23–0.36 in the first centrifugate, increasing to 0.73–0.82 in the third. The corresponding numbers were, respectively, 0.11 and 0.43 for Ap (MW 6,500), and 0 and 0.08 for51Cr-EDTA. These data, combined with calculated exclusion by collagen fibrils, proteoglycans, and HA, indicated that the first centrifugate was mainly derived from the extrafibrillar space, with increasing addition of macromolecular free intrafibrillar fluid in the second and third centrifugates, with each space contributing about equally to the total centrifugate volume. The calculations also indicated that Alb-, IgG-, and Ap-free fluid was mobilized from extrafibrillar space by increasing overlap of excluded territories. An excess of HA in tendon compared with that estimated from centrifugate concentrations suggests a large bound or immobilized HA fraction.

An Electron-Microscope Study of the Reaction of Collagen with Some Monoaldehydes and Bifunctional Aldehydes

1973 ◽  
Vol 12 (3) ◽  
pp. 933-949
Author(s):  
R. W. COX ◽  
R. A. GRANT ◽  
C. M. KENT
Keyword(s):  
Electron Microscope ◽  
Electron Microscope Study ◽  
Cross Linking ◽  
Negative Stain ◽  
Valuable Method ◽  
Native Collagen ◽  
Tail Tendon ◽  
Physical Changes ◽  
Rat Tail ◽  
Tendon Collagen

Rat tail tendon collagen has been treated with the monoaldehydes, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and benzaldehyde, and with the dialdehydes, glyoxal and glutaraldehyde. The treated collagen was then examined in the electron microscope using a negative stain. Alterations to the native collagen pattern were seen with formaldehyde, acetaldehyde, propionaldehyde, glyoxal and glutaraldehyde. A correlation was noted between the changes in the band pattern and the degree of cross-linking estimated from chemical and physical changes in the treated collagen and from measurements of cross-linking made by other workers. The results indicate that the use of electron microscopy and negative staining may be a valuable method of assessing the degree of cross-linking in collagen treated with aldehydes and other reagent.

The equivalence of electron-microscope and X-ray observations on collagen fibres

1955 ◽  
Vol 233 (1192) ◽  
pp. 1-16 ◽  
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Density Fluctuations ◽  
Density Functions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Biological Interest ◽  
Wide Range ◽  
Tail Tendon ◽  
Rat Tail

One of the outstanding properties of collagen fibrils is an axial periodicity of about 640 Å and associated fine structure which can be observed directly in the electron microscope and also may be deduced from observation of low-angle X-ray diffraction. This paper gives first an account of measurements of density fluctuations along the fibril axis for unstained, unshadowed fibrils for one mammalian collagen, rat-tail tendon, and one avian collagen, fowl-neck tendon. The main and subsequent part of the paper shows how the density functions derived from electron micrographs obtained under specified conditions may be used to calculate the intensities of low-angle X-ray diffraction. Complications arise from the fact—of considerable biological interest—that for any one material a wide range of fine structure exists. For this reason it has been necessary to introduce a modulating function to represent the behaviour of a system of fibrils with differing density functions. The calculated structure amplitudes are compared with those measured from low-angle X-ray photographs of dry fibres. Good agreement between the two sets of results is found for rat-tail tendon and fair agreement for fowl-neck tendon. The agreement for fowl-neck tendon is improved by the application of a more general modulating function.

Tendon and ligament from the horse: an ultrastructural study of collagen fibrils and elastic fibres as a function of age

1978 ◽  
Vol 203 (1152) ◽  
pp. 293-303 ◽  
Keyword(s):  
Flexor Tendon ◽  
Extensor Tendon ◽  
Collagen Fibrils ◽  
Collagen Content ◽  
Elastic Fibres ◽  
Suspensory Ligament ◽  
Tail Tendon ◽  
Fibril Diameter ◽  
Rat Tail ◽  
Diameter Distributions

A study has been made of the ultrastructural organization of the collagen fibrils and elastic fibres in tendons and ligaments from horses of ages ranging from 2 months premature to 19 years. Diameter distributions of the collagen fibrils in the common digital extensor tendon, the superficial flexor tendon and the suspensory ligament are unimodal in the foetal tissue and at birth, and at these stages of development the three collagenous tissues are virtually indistinguishable. However, at maturity, the ligament and flexor tendon have bimodal distributions similar to that found for rat-tail tendon. The fibril distribution for extensor tendon remains unimodal until the onset of maturity, beyond which the distribution becomes bimodal. Fibril diameter distributions for ligament, extensor and flexor tendon at old age are, as at birth, virtually identical. An estimate has been made of fibrillar collagen content in the three tissues as a function of age. As with rat-tail tendon, the collagen content increases steadily from birth to maturity, at which stage the content remains fairly constant though it does drop slowly with increasing age. The presence of well developed elastic tissue in foetal and immature tendon and ligament shows that the development of the elastic fibres does not parallel the development of the collagen fibrils. In diseased tissues from a 3 year suspensory ligament and an 8.5 year superficial flexor tendon only immature elastic fibres have been observed. Furthermore, since the collagen fibril diameter distributions in these specimens show a marked change from the norm, it would be expected that the mechanical properties of these tissues would be altered significantly.

scholarly journals The supramolecular structure of bone: X-ray scattering analysis and lateral structure modeling

2016 ◽  
Vol 72 (9) ◽  
pp. 986-996 ◽  
Author(s):  
Hong-Wen Zhou ◽  
Christian Burger ◽  
Hao Wang ◽  
Benjamin S. Hsiao ◽  
Benjamin Chu ◽  
...  
Keyword(s):  
Collagen Fibrils ◽  
Bone Collagen ◽  
X Ray ◽  
X Ray Scattering ◽  
Mineralized Tissues ◽  
Collagen Molecules ◽  
Tail Tendon ◽  
Lateral Structure ◽  
Rat Tail ◽  
Ray Scattering

The evolution of vertebrates required a key development in supramolecular evolution: internally mineralized collagen fibrils. In bone, collagen molecules and mineral crystals form a nanocomposite material comparable to cast iron in tensile strength, but several times lighter and more flexible. Current understanding of the internal nanoscale structure of collagen fibrils, derived from studies of rat tail tendon (RTT), does not explain how nucleation and growth of mineral crystals can occur inside a collagen fibril. Experimental obstacles encountered in studying bone have prevented a solution to this problem for several decades. This report presents a lateral packing model for collagen molecules in bone fibrils, based on the unprecedented observation of multiple resolved equatorial reflections for bone tissue using synchrotron small-angle X-ray scattering (SAXS; ∼1 nm resolution). The deduced structure for pre-mineralized bone fibrils includes features that are not present in RTT: spatially discrete microfibrils. The data are consistent with bone microfibrils similar to pentagonal Smith microfibrils, but are not consistent with the (nondiscrete) quasi-hexagonal microfibrils reported for RTT. These results indicate that collagen fibrils in bone and tendon differ in their internal structure in a manner that allows bone fibrils, but not tendon fibrils, to internally mineralize. In addition, the unique pattern of collagen cross-link types and quantities in mineralized tissues can be can be accounted for, in structural/functional terms, based on a discrete microfibril model.

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