JOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2009
WENTAO LIU
ABSTRACT Pepsin-solubilized collagen prepared from the scales of snakehead (Ophiocephalus argus) was separated into two fractions, major and minor, by NaCl precipitation. The results of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), amino acid composition, and secondary structure showed that the major collagen was typical type I collagen; in contrast, the minor collagen might be classified as type V collagen from the SDS-PAGE patterns and precipitation properties by NaCl. A sharp decrease in solubility of type I collagen was observed at the NaCl concentration of 40 g/L. The maximum and the minimum solubilities of collagen were observed at pH 3 and 8, respectively. Peptide maps of type I collagen digested by trypsin and V8 protease were different from those of calfskin and fish skin collagens. The imino acid content of type I collagen was lower than those of mammalian collagens and so did its denaturation temperature that was 30.3C obtained by viscosity measurement. PRACTICAL APPLICATIONS Collagen has been widely utilized as a material for foods, cosmetics, and pharmaceuticals. However, the use of collagen-derived products from land animals (e.g., bovine and pig) has been called into question because of foot-and-mouth disease crisis etc. Aquatic animal offals, which are readily available and inexpensive, seem to be safe sources for extraction of collagen. This work reports on preparation and characterization of collagen from snakehead scales, which will have potential in supplementing the skins and bones of land animals as an important collagen resource for use in functional food, biomedical, and cosmetic industries. [source]

EFFECT OF SLAUGHTER METHOD ON DEGRADATION OF INTRAMUSCULAR TYPE V COLLAGEN DURING SHORT-TERM CHILLED STORAGE OF CHUB MACKEREL SCOMBER JAPONICUS

JOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2002
KENJI SATO
ABSTRACT The present paper demonstrates that a nonstntggling slaughter method can delay degradation of type V collagen in meat of chub mackerel Scomber japonicus and softening of the meat during postharvest chilled storage. The fish were slaughtered by piercing a knife into nape (nonstruggling method) or by leaving on ground (struggling method) and then stored in an ice box. Sensory study revealed that the postharvest softening of the meat was moderated at 4 and 8 h by the non-struggling slaughter method in comparison with the struggling method. On the basis of the specific solubilization of type V collagen and reduced tyrosine content in it, a cleavage of the nonhelical regions (telopeptides) of the type V collagen occurred during the chilled storage in the fish slaughtered by the struggling method. The degradation of type V collagen was also slower in the meat of the fish slaughtered by the nonstruggling method, which can be directly linked to the moderation of the postharvest softening. [source]

THERAPEUTIC EFFECT OF GREEN TEA EXTRACT ON ADVANCED GLYCATION AND CROSS-LINKING OF COLLAGEN IN THE AORTA OF STREPTOZOTOCIN DIABETIC RATS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2006
Pon Velayutham Anandh Babu
SUMMARY 1The therapeutic effect of green tea extract (GTE) on the aortic collagen content and its characteristics were investigated in streptozotocin diabetic rats. 2Diabetes was induced in rats by a single intra peritoneal injection of streptozotocin (60 mg/kg bodyweight). Six weeks after diabetes induction, GTE was administered orally for four weeks (300 mg/kg bodyweight daily). Systolic blood pressure, blood glucose, anti-oxidant status, collagen content, extent of glycation, collagen linked fluorescence and aortic collagen solubility pattern were determined in experimental rats. 3At the end of the experimental period, there was a significant increase in the systolic blood pressure and blood glucose in diabetic rats. The lipid peroxides increased whereas glutathione and vitamin C levels were decreased in the serum of diabetic rats. The collagen content, extent of glycation, the advanced glycation end products (AGEs) and degree of cross-linking were increased in the aorta of diabetic rats. 4The oral administration of GTE to diabetic rats significantly reduced the systolic blood pressure and blood glucose. The level of lipid peroxides reduced and the content of glutathione and vitamin C increased in the serum of GTE treated diabetic rats. Green tea extract also impede the accumulation of aortic collagen, extent of glycation, formation of AGEs and cross-linking of collagen in diabetic rats. The antihyperglycemic, anti-oxidant and antiglycating effects of GTE ascribed for these beneficial effects. In conclusion, green tea may have therapeutic effect in the treatment of cardiovascular complications characterized by increased AGE accumulation and protein cross-linking associated with diabetes. [source]

CHARACTERIZATION AND COMPARISON OF COLLAGENS EXTRACTED FROM THE DIGESTIVE TRACT AND SKIN OF A JAPANESE AMBERJACK SERIOLA QUINQUERADIATA

JOURNAL OF FOOD BIOCHEMISTRY, Issue 6 2009
MAKI NISHIMOTO
ABSTRACT Collagen was extracted from the digestive tract and skin of a Japanese amberjack (Seriola quinqueradiata) by acid extraction and limited pepsin digestion. The amounts of collagen solubilized from the digestive tract were smaller than those from the skin. Based on the solubility in NaCl solution, electrophoretic and peptide map patterns, and amino acid composition, the main digestive tract collagen was identified as type I, having characteristics different from those of the body wall collagen in cyclostome intestine. Further, the degree of hydroxylation of prolyl and lysyl residues in the type I collagen of the digestive tract is significantly higher than that of the skin. Collagen preparations from the digestive tract have a higher ratio of type V collagen than those from the skin. Hence, the digestive tract collagen differs from that in the skin in the degree or property of intermolecular crosslinking, posttranslational modification, and molecular species composition. PRACTICAL APPLICATIONS Partial hydrolyzate of gelatin, in other word collagen peptide, has gained popularity as a food ingredient, as it has been suggested to have health benefits, such as improvement of skin and joint conditions. Recently, attention toward collagen derived from marine origin such as fish skin increased because of the outbreak of bovine spongiform encephalopathy. Large amounts of the digestive tract, stomach, intestine and adhesion tissues are generated by fishery industries and most of them are by-products of low value. Although these organs are also rich in collagen, the collagen in fish digestive tract has not been characterized. The present study demonstrates that the collagen in digestive tract differs from the skin collagen in the solubility, posttranslational modification and molecular species composition. These facts suggest that modified collagen peptides might be obtained from the digestive tract. [source]

A Randomized, Bilateral, Prospective Comparison of Calcium Hydroxylapatite Microspheres versus Human-Based Collagen for the Correction of Nasolabial Folds

DERMATOLOGIC SURGERY, Issue 2007
STACY SMITH MD
BACKGROUND Current soft tissue fillers are a compromise between ease of use, duration of correction, reactivity, and cost. A product utilizing calcium hydroxylapatite (CaHA) is currently being used as a soft tissue filler. OBJECTIVE The objective was to compare the efficacy and safety of CaHA microspheres versus human-based collagen for the correction of nasolabial folds. MATERIALS AND METHODS Four centers enrolled 117 subjects with moderate to deep nasolabial folds. Subjects received CaHA on one side of the face and human collagen on the other. Up to two touch-ups were allowed. A blinded panel of experts evaluated subject photographs from initial and follow-up visits. RESULTS Seventy-nine percent of subjects had superior improvement on the CaHA side through 6 months (p<.0001). For optimal correction, significantly less volume and fewer injections were needed for CaHA than for collagen (p<.0001). Adverse event rates were comparable, with some increase in bruising and edema for CaHA-treated sides. Adverse event duration was similar for both groups and generally resolved within 14 to 21 days. CONCLUSION This CaHA-based product gives significantly longer-lasting correction of nasolabial folds compared to human collagen. Less total material and fewer injections are required. The adverse event profile of the product is similar to the collagen-based product. [source]

Interaction of Osteoblasts with Macroporous Scaffolds Made of PLLA/PCL Blends Modified with Collagen and Hydroxyapatite,

ADVANCED ENGINEERING MATERIALS, Issue 8 2009
Halil Murat Aydin
To mimic natural bone, a tissue engineering scaffold was developed that combines inorganic and organic components of natural bone, its pore diameter, and its interconnected structure. Collagen was coated onto a PLLA/PCL scaffold and hydroxyapatite particles were delivered throughout the polymer matrix much more easily than with other techniques thanks to the porosity-forming method of combining two porogens, namely, salt leaching and supercritical CO2 extraction. Compared with other coating techniques, this procedure can be performed readily and homogeneous 3D hydroxyapatite coating was achieved. [source]

Aegyptin displays high-affinity for the von Willebrand factor binding site (RGQOGVMGF) in collagen and inhibits carotid thrombus formation in vivo

FEBS JOURNAL, Issue 2 2010
Eric Calvo
Aegyptin is a 30 kDa mosquito salivary gland protein that binds to collagen and inhibits platelet aggregation. We have studied the biophysical properties of aegyptin and its mechanism of action. Light-scattering plot showed that aegyptin has an elongated monomeric form, which explains the apparent molecular mass of 110 kDa estimated by gel-filtration chromatography. Surface plasmon resonance identified the sequence RGQOGVMGF (where O is hydroxyproline) that mediates collagen interaction with von Willebrand factor (vWF) as a high-affinity binding site for aegyptin, with a KD of approximately 5 nm. Additionally, aegyptin interacts with the linear peptide RGQPGVMGF and heat-denatured collagen, indicating that the triple helix and hydroxyproline are not a prerequisite for binding. However, aegyptin does not interact with scrambled RGQPGVMGF peptide. Aegyptin also recognizes the peptides (GPO)10 and GFOGER with low affinity (,m range), which respectively represent glycoprotein VI and integrin ,2,1 binding sites in collagen. Truncated forms of aegyptin were engineered, and the C-terminus fragment was shown to interact with collagen and to attenuate platelet aggregation. In addition, aegyptin prevents laser-induced carotid thrombus formation in the presence of Rose Bengal in vivo, without significant bleeding in rats. In conclusion, aegyptin interacts with distinct binding sites in collagen, and is useful tool to inhibit platelet,collagen interaction in vitro and in vivo. Structured digital abstract ,,MINT-7299280, MINT-7299290: Collagen (uniprotkb:P02461) binds (MI:0407) to Aegyptin (uniprotkb:O01949) by enzyme linked immunosorbent assay (MI:0411) ,,MINT-7298991, MINT-7299153, MINT-7299208: Collagen (uniprotkb:P02452) binds (MI:0407) to Aegyptin (uniprotkb:O01949) by surface plasmon resonance (MI:0107) ,,MINT-7299266: Collagen (uniprotkb:P02452) binds (MI:0407) to Aegyptin (uniprotkb:O01949) by fluorescence microscopy (MI:0416) ,,MINT-7299256: Collagen (uniprotkb:P02452) binds (MI:0407) to Aegyptin (uniprotkb:O01949) by solid phase assay (MI:0892) [source]

Y-position cysteine substitution in type I collagen (,1(I) R888C/p.R1066C) is associated with osteogenesis imperfecta/Ehlers-Danlos syndrome phenotype,,

HUMAN MUTATION, Issue 4 2007
Wayne A. Cabral
Abstract The most common mutations in type I collagen causing types II,IV osteogenesis imperfecta (OI) result in substitution for glycine in a Gly-Xaa-Yaa triplet by another amino acid. We delineated a Y-position substitution in a small pedigree with a combined OI/Ehlers-Danlos Syndrome (EDS) phenotype, characterized by moderately decreased DEXA z-score (,1.3 to ,2.6), long bone fractures, and large-joint hyperextensibility. Affected individuals have an ,1(I)R888C (p.R1066C) substitution in one COL1A1 allele. Polyacrylamide gel electrophoresis (PAGE) of [3H]-proline labeled steady-state collagen reveals slight overmodification of the ,1(I) monomer band, much less than expected for a substitution of a neighboring glycine residue, and a faint ,1(I) dimer. Dimers form in about 10% of proband type I collagen. Dimer formation is inefficient compared to a possible 25%, probably because the SH-side chains have less proximity in this Y-position than when substituting for a glycine. Theoretical stability calculations, differential scanning calorimetry (DSC) thermograms, and thermal denaturation curves showed only weak local destabilization from the Y-position substitution in one or two chains of a collagen helix, but greater destabilization is seen in collagen containing dimers. Y-position collagen dimers cause kinking of the helix, resulting in a register shift that is propagated the full length of the helix and causes resistance to procollagen processing by N-proteinase. Collagen containing the Y-position substitution is incorporated into matrix deposited in culture, including immaturely and maturely cross-linked fractions. In vivo, proband dermal fibrils have decreased density and increased diameter compared to controls, with occasional aggregate formation. This report on Y-position substitutions in type I collagen extends the range of phenotypes caused by nonglycine substitutions and shows that, similar to X- and Y-position substitutions in types II and III collagen, the phenotypes resulting from nonglycine substitutions in type I collagen are distinct from those caused by glycine substitutions. Hum Mutat 28(4), 396,405, 2007. Published 2007 Wiley-Liss, Inc. [source]

Embryo development of Corticium candelabrum (Demospongiae: Homosclerophorida)

INVERTEBRATE BIOLOGY, Issue 3 2007
Sonia De Caralt
Abstract. Corticium candelabrum is a homosclerophorid sponge widespread along the rocky Mediterranean sublittoral. Scanning and transmission electron microscopy were used to describe the gametes and larval development. The species is hermaphroditic. Oocytes and spermatocytes are clearly differentiated in April. Embryos develop from June to July when the larvae are released spontaneously. Spermatic cysts originate from choanocyte chambers and spermatogonia from choanocytes by choanocyte mitosis. Oocytes have a nucleolate nucleus and a cytoplasm filled with yolk granules and some lipids. Embryos are surrounded by firmly interlaced follicular cells from the parental tissue. A thin collagen layer lies below the follicular cells. The blastocoel is formed by migration of blastomeres to the morula periphery. Collagen is spread through the whole blastocoel in the embryo, but is organized in a dense layer (basal lamina) separating cells from the blastocoel in the larva. The larva is a typical cinctoblastula. The pseudostratified larval epithelium is formed by ciliated cells. The basal zone of the ciliated cells contains lipid inclusions and some yolk granules; the intermediate zone is occupied by the nucleus; and the apical zone contains abundant electron-lucent vesicles and gives rise to cilia with a single cross-striated rootlet. Numerous paracrystalline structures are contained in vacuoles within both apical and basal zones of the ciliated cells. Several slightly differentiated cell types are present in different parts of the larva. Most cells are ciliated, and show ultrastructural particularities depending on their location in the larvae (antero-lateral, intermediate, and posterior regions). A few smaller cells are non-ciliated. Several features of the C. candelabrum larva seem to support the previously proposed paraphyletic position of homoscleromorphs with respect to the other demosponges. [source]

Collagen architecture and failure processes in bovine patellar cartilage

JOURNAL OF ANATOMY, Issue 4 2001
JACK L. LEWIS
Cartilage fails by fibrillation and wearing away. This study was designed to identify the microscopic failure processes in the collagen network of bovine cartilage using scanning electron microscopy. Cartilage samples from fibrillated cartilage from the bovine patella were removed from the bone, fixed, digested to remove proteoglycans, freeze-fractured, and processed for SEM. The architecture of the collagen network in the normal cartilage was first defined, and then the failure processes were identified by examining sites of fibrillation and at crack tips. The bovine patellar cartilage was organised with a superficial layer composed of 3,5 lamina, attached to a sub-superficial tissue by angled bridging fibrils. Collagen in the sub-superficial tissue was organised in lamina oriented in the radial direction up to the transition zone. Failure of the system occurred by cracks forming in superficial layer and lamina, creating flaps of lamina that rolled up into the larger ,fronds'. Larger cracks not following the laminar planes occurred in the transition, mid, and deep zones. Failure at the crack tips in the sub-superficial tissue appeared to be by peeling of collagen fibrils, as opposed to breaking of collagen fibrils, suggesting a ,glue' bonding the collagen fibrils in a parallel fashion. Cracks propagated by breaking these bonds. This bond could be a site of disease action, since weakening of the bond would accelerate crack propagation. [source]

Composite coating of bonelike apatite particles and collagen fibers on poly L-lactic acid formed through an accelerated biomimetic coprecipitation process

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2006
Yun Chen
Abstract Collagen and apatite were coprecipitated as a composite coating on poly L-lactic acid (PLLA) in an accelerated biomimetic process. The incubation solution contained collagen (1 g/L) and simulated body fluid with 5 times inorganic ionic concentrations as human blood plasma. The coating formed on PLLA films and scaffolds after a 24-h incubation was characterized by using energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM). It was shown that the coating contained carbonated bonelike apatite and collagen, which was similar in composition to natural bone. SEM showed a complex composite coating of submicron bonelike apatite particulates combined with collagen fibrils. It is expected that such biocomposite coating may better facilitate cell interaction and osteoconductivity. This work provided an efficient process to obtain bonelike apatite/collagen composite coating, which is potentially useful in bone tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source]

Influence of cosolvents and in situ forming hydroxyapatite on the mechanical characteristics of collagen films

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2002
Hsiu-O Ho
Abstract Collagen was processed into films in mixtures containing various ratios of water, propylene glycol, and ethanol. An experimental mixture design was applied to characterize the effects of individual solvents and their interactions on the mechanical properties of collagen films. Scanning electron microscopy (SEM) was used to examine the surface properties of collagen films. The ultimate tensile strength (UTS) and related characteristics of collagen films were also evaluated with dynamic mechanical analysis. The effect of in situ forming hydroxyapatite (HAP) within collagen films at a concentration of 10 mM on the physical characteristics of these films was evaluated by the same methods. With X-ray and SEM examinations, it was confirmed that HAP was formed inside the collagen film. However, the UTS of collagen films without HAP was 4,5 times higher than that with HAP. This was probably due to the discontinuity of the film structure caused by HAP in the collagen films. The results of a statistical analysis of the experimental design revealed the influence of the solvent mixtures on the mechanical properties of the collagen films with and without HAP, showing similar responses for the UTS and modulus of elasticity. Both parameters showed a maximal response in the solvent range containing a lower percentage of ethanol with the desired percentage of propylene glycol to plasticize the collagen films. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 22,29, 2002 [source]

Cis-Acting Intronic Elements That Regulate Cartilage-Specific Alternative Splicing of the Type II Collagen (Col2) Pre-mRNA Lie at or Near Splice Site Junction Sequences Flanking Exon 2 of the Gene,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2003
Takayuki Nishiyama
Abstract Knowledge of the cis-acting elements is required for identifying trans-acting splicing factors underlying cartilage-specific alternative splicing of Col2 pre-mRNA. By performing desired deletions in the mouse Col2 pre-mRNA, location of the intronic cis-acting elements was narrowed down to be at or near splice-junction sequences flanking exon 2 of the gene. Introduction: Type II collagen (Col2) pre-mRNA undergoes cartilage-specific alternative splicing involving exon 2 during chondrocyte differentiation. Thus, the trans-acting protein factors that regulate the splicing are associated with the differentiation of chondrocytes. Knowledge of the cognate cis-acting elements is necessary to eventually identify the trans-acting factors. Materials and Methods: To localize the cis-acting sequences, we created several deletions within a minigene containing exon 1 to exon 4 of mouse Col 2 gene and evaluated alternative splicing of the resulting pre-mRNAs in ATDC5 cells, a model of insulin-stimulated chondrocyte differentiation. The first deletion reduced intron 1 from 3799 to 259 bp, the second reduced intron 2 from 1108 to 94 bp, the third combined the above two deletions, and the fourth was derived from the third by removing intron 3 and exon 4. ATDC5 cells harboring these constructs were cultured for up to 21 days with or without insulin. Alternative splicing was evaluated by determining the ratio of Col2B (lacks exon 2) to Col2A (has exon 2) RNAs by reverse transcription-polymerase chain reaction. Results: The deletion in intron 1 had no effect on the alternative splicing while other deletions affected splicing (demonstrated by the presence of splicing intermediates) in cells cultured without insulin or with insulin for 1 week. The splicing intermediates were not seen from any construct when cells were cultured longer (14,21 days) with insulin. Conclusion: These results show that the 259-bp intron 1, the 94-bp intron 2, and exon 2 sequences retained in the fourth construct provide cis-acting signal sufficient for insulin-induced cartilage-specific alternative splicing of Col2 pre-mRNA. [source]

Regional Alterations of Type I Collagen in Rat Tibia Induced by Skeletal Unloading,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2002
Masashi Shiiba
Abstract Skeletal unloading induces loss of mineral density in weight-bearing bones that leads to inferior bone mechanical strength. This appears to be caused by a failure of bone formation; however, its mechanisms still are not well understood. The objective of this study was to characterize collagen, the predominant matrix protein in bone, in various regions of tibia of rats that were subjected to skeletal unloading by 4 weeks tail suspension. Sixteen male Sprague-Dawley rats (4 months old) were divided into tail suspension and ambulatory controls (eight rats each). After the tail suspension, tibias from each animal were collected and divided into five regions and collagen was analyzed. The collagen cross-linking and the extent of lysine (Lys) hydroxylation in unloaded bones were significantly altered in proximal epiphysis, diaphysis, and, in particular, proximal metaphysis but not in distal regions. The pool of immature/nonmineralized collagen measured by its extractability with a chaotropic solvent was significantly increased in proximal metaphysis. These results suggest that skeletal unloading induced an accumulation of post-translationally altered nonmineralized collagen and that these changes are bone region specific. These alterations might be caused by impaired osteoblastic function/differentiation resulting in a mineralization defect. [source]

Hard tissue alterations after socket preservation with additional buccal overbuilding: a study in the beagle dog

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 10 2009
Stefan Fickl
Abstract Objectives: The aim of this study was to histometrically assess alterations of the ridge following socket preservation alone and socket preservation with additional buccal overbuilding. Material and Methods: In five beagle dogs four extraction sites were randomly subjected to one of the following treatments: Tx 1: The socket was filled with BioOss Collagen® and covered with a free gingival graft from the palate. Tx 2: The buccal bone plate was augmented using the GBR-technique, the socket was filled with BioOss Collagen® and covered with a free gingival graft. Tx 3: The buccal bone plate was forced into a buccal direction using a manual bone spreader. The socket was filled with BioOss Collagen® and covered with a free gingival graft from the palate. Tx 4: The socket was filled with BioOss Collagen® and a combined free gingival/connective tissue graft was used to cover the socket and for buccal tissue augmentation. For each experimental site, two histological sections were subjected to histometric analysis and evaluated for (i) vertical bone dimensions and (ii) horizontal bone dimensions. Results: All treatment groups showed horizontal and vertical bone loss. The mean vertical bone loss of the buccal bone plate was significantly lower in Tx 4 than in the other groups, while no statistical significant differences could be detected among the groups in the horizontal dimension. Conclusion: Overbuilding the buccal aspect in combination with socket preservation does not seem to be a suitable technique to compensate for the alterations after tooth extraction. [source]

Tissue alterations after tooth extraction with and without surgical trauma: a volumetric study in the beagle dog

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 4 2008
Stefan Fickl
Abstract Objectives: The aim of this study is to evaluate whether tooth extraction without the elevation of a muco-periosteal flap has advantageous effects on the resorption rate after tooth extraction. Material and Methods: In five beagle dogs polyether impressions were taken before the surgery. The roots of the first and second pre-molars (P1 and P2) were extracted and the sites were assigned to one of the following treatments: treatment group (Tx) 1, no treatment; Tx 2, surgical trauma (flap elevation and repositioning); Tx 3, the extraction socket was filled with BioOss Collagen® and closed with a free soft-tissue graft; Tx 4, after flap elevation and repositioning, the extraction socket was treated with BioOss Collagen® and a free soft-tissue graft. Impressions were taken 2 and 4 months after surgery. The casts were scanned, matched together with baseline casts and evaluated with digital image analysis. Results: The "flapless groups" demonstrated significant lower resorption rates both when using socket-preservation techniques and without. Furthermore, socket-preservation techniques yielded better results compared with not treating the socket. Conclusion: The results demonstrate that leaving the periosteum in place decreases the resorption rate of the extraction socket. Furthermore, the treatment of the extraction socket with BioOss Collagen® and a free gingival graft seems beneficial in limiting the resorption process after tooth extraction. [source]

Stability of the hydration layer of tropocollagen: A QM study

JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 4 2010
K. Pálfi
Abstract Collagen is a triple helical protein, highly hydrated in nature. Bella and Berman (J Mol Biol 1996, 264, 734) have reported the structure of the first hydration layer. Water molecules form bridges of different length around the POG repeats and self assemble into left-handed helical water threads. To explore the stability of these specifically hydrated places, we have designed suitable QM models: each comprises a triple helix formed by 18 residues surrounded by 8 to 12 explicit waters. Two sets of amino acids were used, one standing for the core structural subunit of tropocollagen (POG-model) and one for its natural enzyme recognition sites (AAG-model). We have determined the stability order of the water binding places, the strongest being ,8.1 kcal mol,1, while the weakest ,6.1 kcal mol,1 per hydrogen bond. In X-ray structures, each triplet of tropocollagen is shielded by six to nine water molecules. Beside the mandatory six, the "surplus" three water molecules further strengthen the binding of all the others. However, the displacement of selected water molecules turns out to be energy neutral. These water binding places on the surface of the triple helix can provide explanation on how an almost liquid-like hydration environment exists between the closely packed tropocollagens (Henkelman et al., Magn Reson Med 1994, 32, 592). It seems that these water reservoirs or buffers can provide space for "hole conduction" of water molecules and thus contribute to the elasticity of collagen. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 [source]

Cutaneous mesenchymal hamartoma with mixed myogenous differentiation

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 4 2006
John Edwin Schrecengost
A 3-month-old infant girl presented with a polypoid lesion in the perianal region. No changes in this lesion had been noted since birth. Microscopic examination of the excised specimen showed a mixture of mesenchymal elements, dominated by haphazard thin fascicles of skeletal muscle. Collagen and vascular changes were also apparent. Immunohistochemistry showed positive staining for muscle-specific actin and desmin in the fascicular components of the lesion, and smooth muscle actin, desmin, and h-caldesmon positivity in a haphazard collection of muscle fibers in the deep dermis and anal submucosa. Numerous Verhoeff-van Gieson positive elastic fibers were also noted. Hamartomas containing skeletal muscle have rarely been reported outside of the head and neck region. They must be distinguished from a variety of other tumors, including juvenile rhabdomyoma, benign Triton tumor, and rhabdomyosarcoma. [source]

CHARACTERIZATION AND COMPARISON OF COLLAGENS EXTRACTED FROM THE DIGESTIVE TRACT AND SKIN OF A JAPANESE AMBERJACK SERIOLA QUINQUERADIATA

PREPARATION AND CHARACTERIZATION OF PEPSIN-SOLUBILIZED TYPE I COLLAGEN FROM THE SCALES OF SNAKEHEAD (OPHIOCEPHALUS ARGUS)

Partially Purified Collagen from Refiner Discharge of Pacific Whiting Surimi Processing

JOURNAL OF FOOD SCIENCE, Issue 8 2005
Jin Soo Kim
ABSTRACT The physicochemical properties of acid-soluble collagen (ASC) from refiner discharge and the partially purified collagen (PPC) from both the refiner discharge and the fish skin were evaluated. Yield of collagen from refiner discharge was 34% higher in PPC than ASC. Mercury, lead, cadmium, and chromium contents of PPC from refiner discharge were not detected. There was no difference in the pattern of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) between ASC and PPC from refiner discharge. PPC from refiner discharge showed better functional properties than that from skin and was similar to ASC: whiteness, solubility, emulsifying activity, and cooking stability. Therefore, PPC from refiner discharge could be used as a new resource. [source]

Interdependence Between Heat Solubility and Pyridinoline Contents of Squid Mantle Collagen

JOURNAL OF FOOD SCIENCE, Issue 2 2001
M. Ando
ABSTRACT: A considerable amount of squid mantle collagen, 45% to 70% of total collagen, was not solubilized even after 30 min of heating in boiling water with its fibrous structure left intact. Pyridinoline, one of the major intermo-lecular crosslinks in matured collagen, was more predominantly included in the insoluble collagen than in the soluble one (p < 0.05). These results suggest that pyridinoline is closely related to the heat solubility of squid collagen. [source]

Immunochemical and Immunohistochemical Identification of a Minor Collagen in Raw Muscles of Decapod Mollusks

JOURNAL OF FOOD SCIENCE, Issue 4 2000
S. Mizuta
ABSTRACT: Approximately 10% of total muscle collagen in 6 decapod molluskan species was recovered as minor collagenous fractions by limited pepsin digestion and differential salt precipitation. The main alpha components (,1) in these fractions showed similar peptide maps of V-8 protease and lysyl endopeptidase digests to each other and had reactivity to the antiserum against the al component of the minor collagen (named Type SQ-II) from Todarodes pacificus muscle in immunoblot analysis. These results suggested that the minor molecular species of collagen corresponding to Type SQ-II of Todarodes pacificus was widely distributed in the mantle muscle of decapod mollusks. In addition, immunohistochemical experiments revealed that Type SQ-II collagen distributed mainly in intramuscular thin connective tissue (endomysium), suggesting the functional importance of this molecule to the development of meat texture of decapod mollusks. [source]

Non-enzymatic glycation of chondrocyte-seeded collagen gels for cartilage tissue engineering

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 11 2008
Rani Roy
Abstract Collagen glycated with ribose (250 mM) in solution (pre-glycation) and as a gel (post-glycation) was seeded with chondrocytes and the effects of glycation on chondrocyte matrix assembly in culture were determined. Pre-glycation enhanced GAG accumulation significantly over controls at both 2 and 4 weeks (p,<,0.05), although at both time points there were no statistical differences in cell number between pre-glycated and control gels. The increased proteoglycan accumulation was shown to be in part due to significantly increased GAG retention by the pre-glycated constructs (p,<,0.05). Total collagen content in these pre-glycated gels was also significantly higher than unglycated gels at 4 weeks (p,<,0.05). With post-glycation of collagen gels, chondrocyte number and GAG accumulation were all significantly lower than controls (p,<,0.05). Post-glycation also inhibited GAG retention by the constructs (p,<,0.05). Given these results, pre-glycation may be an improved processing method for collagen gels for tissue engineering techniques. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1434,1439, 2008 [source]

Changes in gene expression of individual matrix metalloproteinases differ in response to mechanical unloading of tendon fascicles in explant culture

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 10 2008
Diane R. Leigh
Abstract Immobilization of the tendon and ligament has been shown to result in a rapid and significant decrease in material properties. It has been proposed that tissue degradation leading to tendon rupture or pain in humans may also be linked to mechanical unloading following focal tendon injury. Hence, understanding the remodeling mechanism associated with mechanical unloading has relevance for the human conditions of immobilization (e.g., casting), delayed repair of tendon ruptures, and potentially overuse injuries as well. This is the first study to investigate the time course of gene expression changes associated with tissue harvest and mechanical unloading culture in an explant model. Rat tail tendon fascicles were harvested and placed in culture unloaded for up to 48 h and then evaluated using qRT-PCR for changes in two anabolic and four catabolic genes at 12 time points. Our data demonstrates that Type I Collagen, Decorin, Cathepsin K, and MMP2 gene expression are relatively insensitive to unloaded culture conditions. However, changes in both MMP3 and MMP13 gene expression are rapid, dramatic, sustained, and changing during at least the first 48 h of unloaded culture. This data will help to further elucidate the mechanism for the loss of mechanical properties associated with mechanical unloading in tendon. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1306,1312, 2008 [source]

Role of side chains in collagen triple helix stabilization and partner recognition,

JOURNAL OF PEPTIDE SCIENCE, Issue 3 2009
Rita Berisio
Abstract Collagen is a widespread protein family involved in a variety of biological processes. The complexity of collagen and its fibrous nature prevent detailed investigations on the full-length protein. Reductionist approaches conducted by dissecting the protein complexity through the use of model peptides have proved to be quite effective. There are, however, several issues regarding structure,stability relationships, aggregation in higher-order assemblies, and partner recognition that are still extensively investigated. In this review, we discuss the role that side chains play in triple helix stabilization and in partner recognition. On the basis of recent literature data, we show that collagen triple helix stability is the result of the interplay of different factors. As a general trend, interactions established by amino/imino acid side chains within the triple helix scaffold effectively modulate the intrinsic residue propensity for this common structural motif. The use of peptide models has also highlighted the role that side chains play in collagen self-association and in its interactions with receptors. Valuable examples in these fields are illustrated. Finally, future actions required to obtain more detailed information on the structure and the function of this complex protein are also delineated. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd. [source]

Flutamide inhibits nifedipine- and interleukin-1,-induced collagen overproduction in gingival fibroblasts

JOURNAL OF PERIODONTAL RESEARCH, Issue 4 2010
H.-K. Lu
Lu H-K, Tseng C-C, Lee Y-H, Li C-L, Wang L-F. Flutamide inhibits nifedipine- and interleukin-1,-induced collagen overproduction in gingival fibroblasts. J Periodont Res 2010; 45: 451,457. © 2010 John Wiley & Sons A/S Background and Objective:, To understand the role of the androgen receptor in gingival overgrowth, the effects of flutamide on interleukin-1,- and nifedipine-induced gene expression of connective tissue growth factor (CTGF/CCN2) and collagen production in gingival fibroblasts were examined. Material and Methods:, Gingival fibroblasts from healthy subjects and patients with dihydropyridine-induced gingival overgrowth (DIGO) were used. Confluent cells were treated with nifedipine, interleukin-1, or both. The mRNA expression was examined using real-time polymerase chain reaction, and the concentration of total soluble collagen in conditioned media was analysed by Sircol Collagen Assay. In addition, the protein expressions of androgen receptor, CTGF/CCN2 and type I collagen in gingival tissue were determined by western blot. Results:, Interleukin-1, was more potent than nifedipine in stimulating CTGF/CCN2 and procollagen ,1(I) mRNA expression, and there was an additive effect of the two drugs. Healthy cells exhibited an equal or stronger response of procollagen ,1(I) than those with DIGO, but DIGO cells displayed a stronger response in the secretion of soluble collagen in the same conditions. Flutamide, an androgen receptor antagonist, inhibited stimulation by nifedipine or interleukin-1,. Additionally, the protein expressions of androgen receptor and type I collagen were higher in DIGO gingival tissue than those in healthy gingival tissue. Conclusion:, The data suggest that both nifedipine and interleukin-1, play an important role in DIGO via androgen receptor upregulation and that gingival overgrowth is mainly due to collagen accumulation. Flutamide decreases the gene expression and protein production of collagen from dihydropyridine-induced overgrowth cells. [source]

Nucleation of Hydroxyapatite Crystal through Chemical Interaction with Collagen

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2000
Sang-Hoon Rhee
The nucleation of hydroxyapatite (HAp) crystal through chemical interaction with collagen was investigated. A collagen membrane was soaked in a supersaturated simulated body fluid (1.5 SBF) solution with ion concentrations at 1.5 times that of normal simulated body fluid (1.0 SBF). A few carbonate-containing HAp crystals were formed mostly on the edge-side of the collagen membrane after 4 weeks. In the Fourier-transform infrared spectometry (FTIR) results, the carboxylate band of the collagen membrane showed red chemical shifts after the formation of HAp crystals, which coincided well with the decrease of the calculated bond orders of the carboxylate group when chelated with a calcium ion, which emulated the first-step nucleation of HAp crystal on the carboxylate group of collagen. The result implies that the binding of a calcium ion to the carboxylate group of collagen is one of the key factors for the nucleation of HAp crystals in a 1.5 SBF solution. [source]

Collagen promotes sustained glycoprotein VI signaling in platelets and cell lines

JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2007
M. G. TOMLINSON
Summary. Background:,Glycoprotein (GP)VI is the major signaling receptor for collagen on platelets and signals via the associated FcR,-chain, which has an immunoreceptor tyrosine-containing activation motif (ITAM). Objective:,To determine why GPVI,FcR, signals poorly, or not at all, in response to collagen in hematopoietic cell lines, despite robust responses to the GPVI-reactive snake venom toxin convulxin. Methods and results:,Using a nuclear factor of activated T-cells (NFAT) transcriptional reporter assay, a sensitive readout for sustained ITAM signaling, we demonstrate collagen-induced GPVI,FcR, signaling in hematopoietic cell lines. This is accompanied by relatively weak but sustained protein tyrosine phosphorylation, in contrast to the stronger but transient response to convulxin. Sustained signaling by collagen is also observed in platelets and is necessary for the maintenance of spreading on collagen. Finally, in cell lines, the inhibitory collagen receptor leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1), which is not expressed on platelets but is present on most hematopoietic cells, inhibits GPVI responses to collagen but not convulxin. Conclusion:,The inability of previous studies to readily detect GPVI collagen signaling in cell lines is probably because of the weak but sustained nature of the signal and the presence of the inhibitory collagen receptor LAIR-1. In platelets, we propose that GPVI,FcR, has evolved to transmit sustained signals in order to maintain spreading over several hours, as well as facilitating rapid activation through release of feedback agonists and integrin activation. The establishment of a cell line NFAT assay will facilitate the molecular dissection of GPVI signaling and the identification of GPVI antagonists in drug discovery. [source]