scholarly journals Supramolecular structure of polymorphic collagen fibrils.

1976 ◽  
Vol 68 (3) ◽  
pp. 521-538 ◽  
Author(s):  
R R Bruns
Keyword(s):  
Electron Microscopy ◽  
Banding Pattern ◽  
Collagen Fibrils ◽  
Graphic Method ◽  
Interaction Sites ◽  
Symmetrical Pattern ◽  
Native Collagen ◽  
Major Period ◽  
Polymorphic Forms ◽  
Specific Band

Reconstituted cartilage collagen fibrils with an oblique banding pattern or with two types of symmetrical patterns, and reconstituted rattail tendon fibrils with a third type of symmetrical pattern were examined by electron microscopy and found to consist of narrow subfibrils having native-type cross-striations. Analysis of the four types of patterns by a graphic method of specific band matching revealed the orientation and axial relation of individual subfibrils and their component molecules. In fibrils with an oblique pattern, subfibrils have the same orientation and a regular 100A axial displacement. Observations on staining characteristics, folded fibrils, and transverse sections of embedded fibrils suggest that the obliquely banded fibrils are ribbonlike or layered structures. In the three types of fibrils with a symmetrical pattern, adjacent subfibrils are oppositely oriented and aligned within a 119-A segment of the 670-A major period. Considered together, the observations suggest that interaction sites on the surface of subfibrils (and perhaps on the surface of native collagen fibrils) occur in various patterns that are manifested accouding to the nature of the environment during fibril formation, and that such patterns can be mapped on the surface of subfibrils by noting the arrangement of subfibrils in polymorphic forms.

Electron Microscopy of Wound Healing in Patients with Hernia

1975 ◽  
Vol 33 ◽  
pp. 352-353
Author(s):  
C.N. Sun ◽  
H.J. White ◽  
R.C. Read
Keyword(s):  
Electron Microscopy ◽  
Wound Healing ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Phosphotungstic Acid ◽  
Rectus Sheath ◽  
Uranyl Acetate ◽  
Collagen Fibrils ◽  
Lead Citrate ◽  
Native Collagen

Previously we have reported the defect of collagen fibrils from herniated rectus sheath. This presentation includes additional sections from postsurgical incisions (10 days) from both control and hernia patients. Small pieces of rectus sheath were fixed in 3% glutaraldehyde in phosphate buffer (pH 7.2) and post fixed with buffered 2% osmium tetroxide. The tissues were then dehydrated in serially increasing concentrations of alcohol and embedded in Epon 812. Sections were stained with 2.5% phosphotungstic acid or uranyl acetate and lead citrate.Previously we found that collagen fibrils from "non-herniated" rectus sheath have uniform diameters and 640 Å periodicity with seven or more intraperiodic bands resembling typical native collagen fibrils, while the fibrils from fascia obtained from patients with direct herniation show considerable variation in diameter. These variations are often found in the same individual fibers with a range from 300 Å to 3000 Å.

scholarly journals THE FINE STRUCTURE OF BOVINE NASAL CARTILAGE

1971 ◽  
Vol 49 (3) ◽  
pp. 650-663 ◽  
Author(s):  
H. Clarke Anderson ◽  
Stanley W. Sajdera
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Banding Pattern ◽  
Collagen Fibrils ◽  
Guanidinium Chloride ◽  
Electron Microscopic ◽  
Nasal Cartilage ◽  
Before And After ◽  
Exhaustive Extraction

Bovine nasal cartilage was studied by electron microscopy before and after extraction with 4 M guanidinium chloride or 1.9 M CaCl2. These solvents removed matrix granules, basophilia, and 85% of the proteoglycan complex, measured as hexuronate. Simultaneously, many collagen fibrils were disaggregated into component microfibrils (approximately 40 A thick). In contrast to the above solvents, exhaustive extraction with 0.5 M guanidinium chloride removed 20% of the proteoglycan complex, and matrix granules were reduced in size but not in number. Extraction with 4 M CaCl2 removed only 10% of the proteoglycan complex, did not remove matrix granules, and caused the normal banding pattern of collagen to disappear. The banding was restored by further treatment with trypsin. Trypsin, before or after 4 M CaCl2, removed matrix granules and 90% of the proteoglycan complex. We conclude that matrix granules are an electron microscopic representation of the proteoglycan complex, and consist of more than one proteoglycan macromolecule. It would appear that 4 M guanidinium chloride and 1.9 M CaCl2, in addition to removing most of the proteoglycan complex, also disaggregate some of the collagen fibrils into their component microfibrils.

Banded Structures in the Connective Tissue of Meningioma

1976 ◽  
Vol 34 ◽  
pp. 234-235
Author(s):  
C. N. Sun ◽  
H. J. White
Keyword(s):  
Connective Tissue ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Collagen Fibrils ◽  
Lead Citrate ◽  
Connective Tissues ◽  
Native Collagen ◽  
Routine Procedures

Previously, we have reported on extracellular cross-striated banded structures in human connective tissues of a variety of organs (1). Since then, more material has been examined and other techniques applied. Recently, we studied a fibrocytic meningioma of the falx. After the specimen was fixed in 4% buffered glutaraldehyde and post-fixed in 1% buffered osmium tetroxide, other routine procedures were followed for embedding in Epon 812. Sections were stained with uranyl acetate and lead citrate. There were numerous cross striated banded structures in aggregated bundle forms found in the connecfive tissue of the tumor. The banded material has a periodicity of about 450 Å and where it assumes a filamentous arrangement, appears to be about 800 Å in diameter. In comparison with the vicinal native collagen fibrils, the banded material Is sometimes about twice the diameter of native collagen.

scholarly journals SYNTHESIS, MIGRATION, AND RELEASE OF PRECURSOR COLLAGEN BY ODONTOBLASTS AS VISUALIZED BY RADIOAUTOGRAPHY AFTER [3H]PROLINE ADMINISTRATION

1974 ◽  
Vol 60 (1) ◽  
pp. 92-127 ◽  
Author(s):  
Melvyn Weinstock ◽  
C. P. Leblond
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Phosphotungstic Acid ◽  
Secretory Granules ◽  
Low Ph ◽  
Collagen Fibrils ◽  
Dentin Collagen ◽  
Odontoblast Process ◽  
High Radioactivity

The elaboration of dentin collagen precursors by the odontoblasts in the incisor teeth of 30–40-g rats was investigated by electron microscopy, histochemistry, and radioautography after intravenous injection of tritium-labeled proline. At 2 min after injection, when the labeling of blood proline was high, radioactivity was restricted to the rough endoplasmic reticulum, indicating that it is the site of synthesis of the polypeptide precursors of collagen, the pro-alpha chains. At 10 min, when the labeling of blood proline had already declined, radioactivity was observed in spherical portions of Golgi saccules containing entangled threads, and, at 20 min, radioactivity appeared in cylindrical portions containing aggregates of parallel threads. The parallel threads measured 280–350 nm in length and stained with the low pH-phosphotungstic acid technique for carbohydrate and with the silver methenamine technique for aldehydes (as did extracellular collagen fibrils). The passage of label from spherical to cylindrical Golgi portions is associated with the reorganization of entangled into parallel threads, which is interpreted as the packing of procollagen molecules. Between 20 and 30 min, prosecretory and secretory granules respectively became labeled. These results indicate that the cylindrical portions of Golgi saccules transform into prosecretory and subsequently into secretory granules. Within these granules, the parallel threads, believed to be procollagen molecules, are transported to the odontoblast process. At 90 min and 4 h after injection, label was present in predentin, indicating that the labeled content of secretory granules had been released into predentin. This occurred by exocytosis as evidenced by the presence of secretory granules in fusion with the plasmalemma of the odontoblast process. It is proposed that pro-alpha chains give rise to procollagen molecules which assemble into parallel aggregates in the Golgi apparatus. Procollagen molecules are then transported within secretory granules to the odontoblast process and released by exocytosis. In predentin procollagen molecules would give rise to tropocollagen molecules, which would then polymerize into collagen fibrils.

The morphogenesis of avian tendon

1956 ◽  
Vol 144 (917) ◽  
pp. 556-572 ◽  
Keyword(s):  
Electron Microscopy ◽  
Average Diameter ◽  
Relative Volume ◽  
Morphological Features ◽  
Collagen Fibrils ◽  
Intercellular Spaces ◽  
Intercellular Substance ◽  
Thin Sections ◽  
Cellular Components ◽  
Development Proceeds

Observations by electron microscopy on thin sections of the metatarsal tendon of embryonic fowls show that in the 8-day embryo the earliest definable collagen fibrils of 80 Å in diameter are intimately associated with the cytoplasm of the compact, apparently syncytial, cells of which the tendon rudiment is composed. As development proceeds, some intracytoplasmic groups of fibrils are distinguishable, but intercellular spaces also develop and these gradually become filled with fibrils; finally, bundles are formed and lie packed between the adjacent cells. Soon the extracellular organization predominates until at 20days the average diameter of the fibrils is 400 Å and the normal 640 Å periodicity of collagen has been achieved. The morphological features demonstrated have been correlated with histochemical data, and the possible function of the various cellular components in the formation of the intercellular substance has been discussed. By the use of sections in which fibrils have been cut exactly transverse to the bundle axis it has been shown that each fibril is invested by interfibrillar material. As the diameter of the fibrils increases with age the relative volume of interfibrillar material within a bundle diminishes; it is therefore concluded that this material must contain either collagen or the necessary precursors in order to account for the enlargement of the fibrils. Thus the interfibrillar material is of fundamental importance to the formation and growth of the collagen fibrils.

Collagen Phagocytosis by Fibroblasts in the Periodontal Ligament of the Mouse Molar During the Initial Phase of Hypofunction

1987 ◽  
Vol 66 (12) ◽  
pp. 1708-1712 ◽  
Author(s):  
W. Beertsen
Keyword(s):  
Electron Microscopy ◽  
Morphometric Analysis ◽  
Extracellular Space ◽  
Periodontal Ligament ◽  
Initial Phase ◽  
Volume Density ◽  
Collagen Fibrils ◽  
Fibrillar Collagen ◽  
Collagen Phagocytosis

This study was undertaken in order to determine whether hypofunction of teeth is associated with changes in collagen phagocytosis by fibroblasts of the periodontal ligament. In mice, the lower right molars were extracted and the animals killed one, two, three, four, or seven days later. The maxillary first molars with their surrounding periodontium were processed for electron microscopy and their periodontal ligament subjected to morphometric analysis. It was observed that, whereas the volume density of extracellular collagen in the ligament of the hypofunctional molars decreased from 50% to 30% during the course of the experiment the fraction of fibrillar collagen ingested by the cells increased over two-fold. This increase was already manifest very shortly after the onset of the experiment and offers an explanation for the net loss of collagen fibrils from the extracellular space.

scholarly journals Comparison of the Structural Characteristics of Native Collagen Fibrils Derived from Bovine Tendons Using Two Different Methods: Modified Acid-Solubilized and Pepsin-Aided Extraction

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 358 ◽  
Author(s):  
Haiyan Ju ◽  
Xiuying Liu ◽  
Gang Zhang ◽  
Dezheng Liu ◽  
Yongsheng Yang
Keyword(s):  
Type I Collagen ◽  
Structural Characteristics ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Dry Weight ◽  
Collagen Fibrils ◽  
Type I ◽  
X Ray Diffraction ◽  
Aggregation Structure ◽  
Native Collagen

Native collagen fibrils (CF) were successfully extracted from bovine tendons using two different methods: modified acid-solubilized extraction for A-CF and pepsin-aided method for P-CF. The yields of A-CF and P-CF were up to 64.91% (±1.07% SD) and 56.78% (±1.22% SD) (dry weight basis), respectively. The analyses of both amino acid composition and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that A-CF and P-CF were type I collagen fibrils. Both A-CF and P-CF retained the intact crystallinity and integrity of type I collagen’s natural structure by FTIR spectra, circular dichroism spectroscopy (CD) and X-ray diffraction detection. The aggregation structures of A-CF and P-CF were displayed by UV–Vis. However, A-CF showed more intact aggregation structure than P-CF. Microstructure and D-periodicities of A-CF and P-CF were observed (SEM and TEM). The diameters of A-CF and P-CF are about 386 and 282 nm, respectively. Although both A-CF and P-CF were theoretically concordant with the Schmitt hypothesis, A-CF was of evener thickness and higher integrity in terms of aggregation structure than P-CF. Modified acid-solubilized method provides a potential non-enzyme alternative to extract native collagen fibrils with uniform thickness and integral aggregation structure.

scholarly journals Highly sensitive single-fibril erosion assay demonstrates mechanochemical switch in native collagen fibrils

2012 ◽  
Vol 12 (2) ◽  
pp. 291-300 ◽  
Author(s):  
Brendan P. Flynn ◽  
Graham E. Tilburey ◽  
Jeffrey W. Ruberti
Keyword(s):  
Collagen Fibrils ◽  
Highly Sensitive ◽  
Native Collagen
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