Biosynthetic Processing of Collagen Molecules

2005 ◽  
pp. 149-183 ◽  
Author(s):  
Daniel S. Greenspan
Keyword(s):  
Collagen Molecules

scholarly journals Heat impact during laser ablation extraction of mineralised tissue micropillars

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Samuel McPhee ◽  
Alexander Groetsch ◽  
Jonathan D. Shephard ◽  
Uwe Wolfram
Keyword(s):  
Laser Ablation ◽  
Mechanical Testing ◽  
Laser Scanning ◽  
Pulsed Laser ◽  
Temperature Response ◽  
Collagen Fibre ◽  
Pulsed Laser Ablation ◽  
Collagen Molecules ◽  
Ultrashort Pulsed Laser ◽  
The Impact

AbstractThe underlying constraint of ultrashort pulsed laser ablation in both the clinical and micromachining setting is the uncertainty regarding the impact on the composition of material surrounding the ablated region. A heat model representing the laser-tissue interaction was implemented into a finite element suite to assess the cumulative temperature response of bone during ultrashort pulsed laser ablation. As an example, we focus on the extraction of mineralised collagen fibre micropillars. Laser induced heating can cause denaturation of the collagen, resulting in ultrastructural loss which could affect mechanical testing results. Laser parameters were taken from a used micropillar extraction protocol. The laser scanning pattern consisted of 4085 pulses, with a final radial pass being 22 $$\upmu {\text {m}}$$ μ m away from the micropillar. The micropillar temperature was elevated to 70.58 $$^{\circ }{\text {C}}$$ ∘ C , remaining 79.42 $$^{\circ }{\text {C}}$$ ∘ C lower than that of which we interpret as an onset for denaturation. We verified the results by means of Raman microscopy and Energy Dispersive X-ray Microanalysis and found the laser-material interaction had no effect on the collagen molecules or mineral nanocrystals that constitute the micropillars. We, thus, show that ultrashort pulsed laser ablation is a safe and viable tool to fabricate bone specimens for mechanical testing at the micro- and nanoscale and we provide a computational model to efficiently assess this.

scholarly journals Chemistry of collagen cross-links: glucose-mediated covalent cross-linking of type-IV collagen in lens capsules

1993 ◽  
Vol 296 (2) ◽  
pp. 489-496 ◽  
Author(s):  
A J Bailey ◽  
T J Sims ◽  
N C Avery ◽  
C A Miles
Keyword(s):  
Type Iv Collagen ◽  
Cross Linking ◽  
Mechanical And Thermal Properties ◽  
Maximum Strain ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Type Iv ◽  
Collagen Molecules ◽  
Cross Links

The incubation of lens capsules with glucose in vitro resulted in changes in the mechanical and thermal properties of type-IV collagen consistent with increased cross-linking. Differential scanning calorimetry (d.s.c.) of fresh lens capsules showed two major peaks at melting temperatures Tm 1 and Tm 2 at approx. 54 degrees C and 90 degrees C, which can be attributed to the denaturation of the triple helix and 7S domains respectively. Glycosylation of lens capsules in vitro for 24 weeks caused an increase in Tm 1 from 54 degrees C to 61 degrees C, while non-glycosylated, control incubated capsules increased to a Tm 1 of 57 degrees C. The higher temperature required to denature the type-IV collagen after incubation in vitro suggested increased intermolecular cross-linking. Glycosylated lens capsules were more brittle than fresh samples, breaking at a maximum strain of 36.8 +/- 1.8% compared with 75.6 +/- 6.3% for the fresh samples. The stress at maximum strain (or ‘strength’) was dramatically reduced from 12.0 to 4.7 N.mm.mg-1 after glycosylation in vitro. The increased constraints within the system leading to loss of strength and increased brittleness suggested not only the presence of more cross-links but a difference in the location of these cross-links compared with the natural lysyl-aldehyde-derived cross-links. The chemical nature of the fluorescent glucose-derived cross-link following glycosylation was determined as pentosidine, at a concentration of 1 pentosidine molecule per 600 collagen molecules after 24 weeks incubation. Pentosidine was also determined in the lens capsules obtained from uncontrolled diabetics at a level of about 1 per 100 collagen molecules. The concentration of these pentosidine cross-links is far too small to account for the observed changes in the thermal and mechanical properties following incubation in vitro, clearly indicating that another as yet undefined, but apparently more important cross-linking mechanism mediated by glucose is taking place.

A new model for packing of type-I collagen molecules in the native fibril

1981 ◽  
Vol 1 (10) ◽  
pp. 801-810 ◽  
Author(s):  
Karl A. Piez ◽  
Benes L. Trus
Keyword(s):  
Type I Collagen ◽  
Hexagonal Lattice ◽  
Three Dimensional ◽  
Equatorial Region ◽  
Type I ◽  
X Ray Diffraction ◽  
X Ray ◽  
Left Handed ◽  
Crystal Model ◽  
Collagen Molecules

A specific fibril model is presented consisting of bundles of five-stranded microfibrils, which are usually disordered (except axially) but under lateral compression become ordered. The features are as follows (where D = 234 residues or 67 nm): (1) D-staggered collagen molecules 4.5 D long in the helical microfibril have a left-handed supercoil with a pitch of 400–700 residues, but microfibrils need not have helical symmetry. (2) Straight-tilted 0.5-D overlap regions on a near-hexagonal lattice contribute the discrete x-ray diffraction reflections arising from lateral order, while the gap regions remain disordered. (3) The overlap regions are equivalent, but are crystallographically distinguished by systematic displacements from the near-hexagonal lattice. (4) The unit cell is the same as in a recently proposed three-dimensional crystal model, and calculated intensities in the equatorial region of the x-ray diffraction pattern agree with observed values.

Assembly of Type I Collagen on PVA Film Induced by Glutaraldehyde Vapor

2011 ◽  
Vol 284-286 ◽  
pp. 1794-1799 ◽  
Author(s):  
Yu Lu Wang ◽  
Xue Pin Liao ◽  
Bi Shi
Keyword(s):  
Network Structure ◽  
Type I Collagen ◽  
Collagen Fibers ◽  
Type I ◽  
Collagen Concentration ◽  
Collagen Molecules ◽  
Induced Reaction ◽  
Calf Skin

Type I collagen was isolated from calf skin and its assembly on PVA film induced by glutaraldehyde vapor was investigated. It was found that the collagen molecules were firstly orientationally assembled into collagen fibers under the inducement of glutaraldehyde vapor. Then the collagen fibers could be further aggregated into novel network structure in proper conditions of the induced reaction. The morphology of the assembled collagen fibers was depended on induced time and concentration of collagen. The network arrangement could be obtained after being induced for 72h when collagen concentration was 2.5mg/ml. At higher concentration of collagen (5 mg/ml), the collagen fibers with larger dimension were obtained, but the growth of fibers was almost in one direction.

scholarly journals Collagen heterogeneity within different growth regions of long bones of rachitic and nonrachitic chicks

1972 ◽  
Vol 127 (4) ◽  
pp. 715-720 ◽  
Author(s):  
Bryan P. Toole ◽  
Andrew H. Kang ◽  
Robert L. Trelstad ◽  
Jerome Gross
Keyword(s):  
Vitamin D ◽  
Amino Acid ◽  
Bone Matrix ◽  
Bone Collagen ◽  
Long Bone ◽  
Long Bones ◽  
Collagen Structure ◽  
Collagen Molecules ◽  
Relationship Of ◽  
Chain Type

The different anatomical regions involved in osteogenesis in the chick long bone have been examined for heterogeneities in collagen structure that might relate to the mechanism of ossification. Experimentally induced lathyrism was employed to enhance collagen solubility, and vitamin D deficiency to allow accumulation of osteoid, the precursor of bone matrix. The extractable lathyritic collagens of the cartilaginous and osseous regions of growing long bones from rachitic and non-rachitic chicks were examined for α-chain type and amino acid composition. In both groups of animals the growth plate and cartilaginous regions of the epiphysis gave collagen molecules of the constitution [α1(II)]3, whereas the ossifying regions contained [α1(I)]2 α2. The degree of hydroxylation of the lysine moieties was increased by approximately 50% in the α1(I)-chain and α2-chain of rachitic bone collagen. Since uncalcified osteoid is greatly enriched in rachitic bone, it is concluded that the collagen of osteoid has the configuration [α1(I)]2 α2, similar to that of bone matrix, but has an elevated hydroxylysine content. The possible relationship of this difference to the mechanism of calcification is discussed.

scholarly journals Inhibition of laminin self-assembly and interaction with type IV collagen by antibodies to the terminal domain of the long arm.

1986 ◽  
Vol 103 (5) ◽  
pp. 1689-1697 ◽  
Author(s):  
A S Charonis ◽  
E C Tsilibary ◽  
T Saku ◽  
H Furthmayr
Keyword(s):  
Self Assembly ◽  
Binding Sites ◽  
Type Iv Collagen ◽  
Specific Interaction ◽  
Basement Membranes ◽  
Complex Domain ◽  
Peptide Fragment ◽  
Type Iv ◽  
Collagen Molecules

Laminin is a major glycoprotein of the basement membrane. Although its precise localization and orientation within this structure is unknown, it is presumably anchored to other macromolecules such as type IV collagen or proteoheparan sulfate. In vitro, laminin has the ability to self-assemble and to bind to type IV collagen molecules at distinct sites. To identify more precisely the domains of the complex, cross-shaped laminin molecule that are involved in these interactions, images of laminin-laminin dimers and laminin-type IV collagen complexes obtained by the rotary shadowing method were analyzed. We observed that the complex domain at the end of the long arm of laminin is predominantly involved in these interactions. By using Fab fragments of antibodies specific for a peptide fragment derived from this complex domain, it is shown that laminin self-assembly is inhibited in their presence, as measured by turbidity and by electron microscopy. In addition, these antibodies inhibit the specific interaction of laminin with type IV collagen. These data suggest that the complex domain at the end of the long arm of laminin contains binding sites of potential importance for the assembly of basement membranes.

scholarly journals Ultrastructural localization of type V collagen in rat kidney.

1982 ◽  
Vol 92 (2) ◽  
pp. 343-349 ◽  
Author(s):  
A Martinez-Hernandez ◽  
S Gay ◽  
E J Miller
Keyword(s):  
Type I Collagen ◽  
Rat Kidney ◽  
Ultrastructural Localization ◽  
Particulate Material ◽  
Basement Membranes ◽  
Type I ◽  
Type V Collagen ◽  
Collagen Molecules ◽  
Immunohistochemical Studies ◽  
Type V

Antibodies specific for the alpha 1 (V) chain and native collagen molecules containing the alpha 1 (V) chain have been used in electron immunohistochemical studies of rat kidney to determine the ultrastructural distribution of this class of collagen molecules. In addition, antibodies against type I collagen and whole basement membrane were used as markers for interstitial collagen and authentic basement membranes. Our results indicate that type V collagen is present in the renal interstitium in different forms: in close apposition to interstitial collagen fibers; in the stromal aspect of vascular basement membranes; and as particulate material not bound to other structures. On the basis of these findings, we postulate a binding or connecting function for this collagen type.

Solid State NMR Analysis for Hide Powder Tanned by Aluminum, Silicon and Phosphorus Tanning Agents before and after Hydrothermal Denaturation

2021 ◽  
Vol 116 (10) ◽  
Author(s):  
Jun Liu ◽  
Da-hai He ◽  
Hua-lin Chen ◽  
Ke-yi Ding
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
High Field ◽  
Chemical Shifts ◽  
Covalent Bond ◽  
29Si Nmr ◽  
Before And After ◽  
Collagen Molecules ◽  
Field Area ◽  
Aluminum Silicon

In order to investigate the change of chemical bonds between tanning agents and collagen molecules directly, hide powder tanned by aluminum, silicon and phosphorus tanning agents were prepared. The chemical shifts of Al, Si and P in tanned hide powder were analyzed by solid-state 27Al NMR, 29Si NMR and 31P NMR. The results showed that, the chemical shift of Al in aluminum tanned hide powder which interacted with collagen molecules through coordination bond could be regarded as unchanging after hydrothermal denaturation (only slightly moved to high field area). The chemical shift of Si in silicon tanned hide powder which interacted with collagen molecules through hydrogen bond did not change after hydrothermal denaturation. The chemical shift of P in phosphorus tanned hide powder, which interacted with collagen molecules through covalent bond, was obviously shifted to the high field area after hydrothermal denaturation.

scholarly journals Opuntiol Prevents Photoaging of Mouse Skin via Blocking Inflammatory Responses and Collagen Degradation

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
P. Veeramani kandan ◽  
Agilan Balupillai ◽  
G. Kanimozhi ◽  
Haseeb A. Khan ◽  
Abdullah S. Alhomida ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Mouse Skin ◽  
Skin Lesions ◽  
Tnf Α ◽  
Skin Photoaging ◽  
Dermal Collagen ◽  
Collagen Molecules ◽  
Experimental Mouse ◽  
Inflammatory Proteins ◽  
Uva Radiation

In the present study, we investigated the potential of opuntiol, isolated from Opuntia ficus-indica, against UVA radiation-mediated inflammation and skin photoaging in experimental animals. The skin-shaved experimental mouse was subjected to UVA exposure at the dosage of 10 J/cm2 per day for ten consecutive days (cumulative UVA dose: 100 J/cm2). Opuntiol (50 mg/kg b.wt.) was topically applied one hour before each UVA exposure. UVA (100 J/cm2) exposure induces epidermal hyperplasia and collagen disarrangement which leads to the photoaging-associated molecular changes in the mouse skin. Opuntiol pretreatment prevented UVA-linked clinical macroscopic skin lesions and histological changes in the mouse skin. Further, opuntiol prevents UVA-linked dermal collagen fiber loss in the mouse skin. Short-term UVA radiation (100 J/cm2) activates MAPKs through AP-1 and NF-κB p65 transcriptional pathways and subsequently induces the expression of inflammatory proteins and matrix-degrading proteinases in the mouse skin. Interestingly, opuntiol pretreatment inhibited UVA-induced activation of iNOS, VEGF, TNF-α, and COX-2 proteins and consequent activation of MMP-2, MMP-9, and MMP-12 in the mouse skin. Moreover, opuntiol was found to prevent collagen I and III breakdown in UVA radiation-exposed mouse skin. Thus, opuntiol protects mouse skin from UVA radiation-associated photoaging responses through inhibiting inflammatory responses, MAPK activation, and degradation of matrix collagen molecules.

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