Notes

Conflict of interest statement: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper
G. Tronci, S.J. Russell and D.J. Wood are named inventors on a patent related to the fabrication of collagen-based materials.

Type II collagen quantification in experimental chondrogenesis.Type II collagen is an excellent indicator of the cartilage phenotype. Accurate quantification with existing methods requires about 100 micrograms of collagen. We have developed a method which allows for accurate quantification of type II collagen in samples as small as 1 microgram (and sample volumes as little as 1 microliters). Types I and II collagen were pepsin purified, cleaved with cyanogen bromide, and dissolved in sample buffer at concentrations of 025-200 micrograms/microliters. Volumes of 1 microliter were analyzed by electrophoresis on microgels. squalene were scanned on a laser densitometer and the ratios of the alpha 1 (II)CB10 to the alpha 1(I)CB7,8 plus alpha 1(II)CB11 determined.

The cyanogen bromide-derived (CNBr) peptides could be resolved at concentrations as low as 05 microgram/microliter. The ideal working concentration for purified collagens was 1-8 micrograms/microliters. Standard mixtures of both purified and non-purified types I and II collagen were analyzed. At a concentration of 1 microgram/microliter the ratio of the bands referred to above was closely related to the relative proportion of type II collagen, in a polynomial fashion. At 8 micrograms/microliters there was an almost perfect linear relationship. The presence of 15-30% type III collagen had < 5% effect on the measurements of type II collagen. The method is simple, reliable, fast and automated.

It should have good potential for application in cartilage research as it permits quantitation of type II collagen in extremely small samples of tissue.10080/07391102020753578. Epub 2020 Apr 20.Comparative analysis of the viscoelastic properties of collagen-like proteins by Viscoelasticity of collagen is essential for the integrity of connective tissue and its aberrancy may result in collagen dysfunction and the emergence of connective tissue diseases. Precise identification of viscoelastic properties of collagens, and affecting factors are necessary to understand collagen behavior in the extracellular matrix as well as the mechanism of collagen-related diseases. The aim of this study is to investigate the mechanical and viscoelastic properties and time-lapse changes of protein-protein and protein-solvent hydrogen bonds of proline-rich and hydroxyproline-rich collagens by molecular dynamics simulation applying a virtual creep test. To this end, ten different collagen-like protein structures including [(Gly-Pro-Ala)7]3, [(Gly-Pro-Arg)7]3, [(Gly-Pro-Asp)7]3, [(Gly-Pro-Lys)7]3, [(Gly-Pro-Ser)7]3, [(Gly-Pro-Hyp)7]3, [(Gly-Ala-Hyp)7]3, [(Gly-Glu-Hyp)7]3, [(Gly-Leu-Hyp)7]3 and [(Gly-Val-Hyp)7]3 were virtually built and the viscoelastic properties of the structures were determined by virtual creep test according to Kelvin-Voigt model with various constant pulling forces.

squalene pulling forces ranged from 500 piconewton (pN) to 5000 pN were applied. As a result, Young's modulus of the collagens was found positively correlated with the pulling force. The viscosity values and relaxation times were negatively correlated. Results also revealed a decreased number of intramolecular hydrogen bonds in hydroxyproline-rich collagens (but not in proline-rich collagens) and an increased number of protein-solvent hydrogen bonds in response to the increasing pulling force. Our results also confirmed that proline and hydroxyproline are the most critical amino acids in determining the collagen viscoelasticity. We suggest that collagen length and mechanical force may be additional important factors for biomechanical properties and behavior of collagen in the extracellular matrix.Communicated by Ramaswamy H.

Sarma.Collagen species in human aorta: with special reference to basement membrane-associated collagens in the intima and media and their alteration with Collagen species, especially basement membrane or short chain types, of human aorta extracted by limited and repeated pepsin digestions were investigated as to their type dependent solubility by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after differential salt precipitation and cyanogen bromide cleavage. Basement membrane-associated collagens, i.e., types IV, V and VI, were more extractable in the earlier limited pepsin digests than in the later repeated ones, whereas type I collagen was continually extracted. The content of collagen type IV as well as that of type V increased with the proliferative fibrotic process in the intima including the media. Basement membrane collagen type IV showed heterogenous molecular sizes, including alpha 1(IV) and alpha 2(IV) chains.

The alpha 3(V) chain of type V collagen was found in addition to the alpha 1(V) and alpha 2(V) chains. Short chain collagen type VI was detected in the intima and media at a position corresponding to 145 Kd and was reduced to Synovial origins of Rice bodies in joint fluid.Cheung HS, Ryan LM, Kozin F, McCarty DJ.Rice bodies and synovia obtained from knee joints of rheumatoid arthritis patients were solubilized by limited pepsin treatment.
Here's my website: http://en.wikipedia.org/wiki/Squalene