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Auteur Eleanor M. Brown
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United States Department of Agriculture, Agricultural Research Service Eastern Regional Research Center - Mermaid Lane, Wyndmoor, PA - USA
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Effects of neutral salts on collagen structure and chromium-collagen interactions / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIV, N° 2 (02-03/1999)
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Titre : Effects of neutral salts on collagen structure and chromium-collagen interactions Type de document : texte imprimé Auteurs : Eleanor M. Brown, Auteur Année de publication : 1999 Article en page(s) : p. 59-67 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Tanning, the multi-step process whereby complex salts of Cr(III) crosslinking collagen fibrils, is more an art form than a science and the mechanism of the chromium-collagen interaction is poorly understoos. The long range goal of this research is to develop an experimental model with which to study the interactions of Cr(III) with collagen that are characteristic of tanning. In the present study, the thermal stability of acid soluble collagen from bovine skin is studied by circular dichroism spectropolarimetry. The melting curve for the triple helix of calf skin collagen in 0.05 M acetic acid was analyzed in terms of a pre-transition followed by complete denaturation, with a characteristic Tp=34.0°C Td=40.7°C. For pepsin solubilized, adult bovine dermal collagen, slightly lower denaturation temperatures were observed - Tp=31.0°C, Td=37.7°C probably due to the removal of the nonhelical telopeptides in the solubilization of adult skin collagen. The addition of salts, NaCl or KCl, initially had a destabilizing effect on the triple helix, lowering both Tp and Td nearly in parallel. At low concentrations of Nacl, preferential binding occured with apparent dissociation constants Kd(Tp)=0.034 M and K(Td)=0.017 M for calf skin collagen at 1 mg/mL in 0.05 M acetic acid, suggesting the possibility of site preferential interactions contributing to the observed melting behavior. As the salt concentration was increased between 0.1 M and 0.5 M, little further destabilization was observed, Tp and Td became indistinguishable. At 0.4 M NaCl (0.5 M KCl)the samples began to gel. Here, water-structuring effects may play a role. In contrast, under conditions of the model tanning system, where Cr(III) was added at pH 2 and the pH was then adjusted to 4.5 with bicarbonated, the "tanned" collagen gelled at a salt concentration of 0.1 M. Note de contenu : - EXPERIMENTAL : Materials - Spectroscopy - Simulated tanning procedure
- RESULTS : Characterization of soluble collagen - Effects of salts - Simulated tanningEn ligne : https://drive.google.com/file/d/10YW7UOTUD3Ga7f-kWr2fVXz-7Xsp_wEj/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4489
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIV, N° 2 (02-03/1999) . - p. 59-67[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 006972 - Périodique Bibliothèque principale Documentaires Disponible Effects of pretanning processes on bovine hide collagen structure / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVII, N° 1 (01/2012)
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Titre : Effects of pretanning processes on bovine hide collagen structure Type de document : texte imprimé Auteurs : Eleanor M. Brown, Auteur ; Renée J. Latona, Auteur ; Maryann M. Taylor, Auteur ; Rafael A. Garcia, Auteur Année de publication : 2012 Article en page(s) : p. 1-7 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagénases Les collagénases sont des enzymes capables de rompre les liaisons peptidiques du collagène. Elles facilitent la destruction des structures extracellulaires lors de la pathogenèse bactérienne. Ce sont des exotoxines.
La production de collagénases peut être induite lors d'une réponse immunitaire, par les cytokines qui stimulent les cellules telles que les fibroblastes et les ostéoplastes et occasionnent indirectement des lésions tissulaires.
Collagène
Cuirs et peaux
Electrophorèse
Microscopie électronique à balayage
Prétannage
Stabilité thermiqueIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The US meat industry currently produces approximately 35 million cattle hides annually as its most valuable coproduct. These hides serve as raw material, first for the leather industry, and then for the gelatin, and biomaterials industries. The conversion of animal hides into leather is a multistep process that has evolved more as art form than as science. Economic or environmental issues typically dictate changes in beam-house processes that prepare the hide for tanning. The tanner evaluates these changes, in terms of impact on tannery costs and quality of leather produced. Thus far, the effects of beam-house processes on the molecular characteristics of collagen have received little attention. The basis for tanning and most biomaterials applications is the stabilization of the collagen matrix, thus any changes to the molecular characteristics of hide collagen may be expected to impact these applications. This study showed that while the effects of different dehairing processes on the structure and stability of monomeric collagen were similar, the effects on the collagen fiber structure were distinct. These results are anticipated to assist the tanner as well as the manufacturers of collagen-based biomaterials and gelatin to better understand their substrate and changes to it that may occur when beam-house processes are altered. Note de contenu : - Materials
- Sample preparation : powdered hide - Extracted collagen
- Analyses - Scanning Electron Microscopy (SEM) - Susceptibility to collagenase - Electrophoresis - Hydrothermal stability of powdered hide - Thermal stability of extracted collagen
- RESULTS AND DISCUSSION : Scanning Electron Microscopy (SEM) - Susceptibility to collagenase - Hydrothermal stability of powdered hide - Thermal stability of extracted collagenEn ligne : https://drive.google.com/file/d/1HTNem7IR_uqd6Jser9U60Bz_eD4ySqLG/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13296
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Code-barres Cote Support Localisation Section Disponibilité 13555 - Périodique Bibliothèque principale Documentaires Disponible Enzymatic modification of hydrolysis products from collagen using a microbial transglutaminase. I. Physical properties / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVI, N° 9 (09/2001)
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Titre : Enzymatic modification of hydrolysis products from collagen using a microbial transglutaminase. I. Physical properties Type de document : texte imprimé Auteurs : Maryann M. Taylor, Auteur ; Luisa F. Cabeza, Auteur ; William N. Marmer, Auteur ; Eleanor M. Brown, Auteur Année de publication : 2001 Article en page(s) : p. 319-332 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In previously reported research from this laboratory, gelatins, both commercial and experimental of varying gel strengths, were chemically modified using glutaraldehyde, glyoxal, and carbodiimide. These classical modifications effectively changed the physical and functional properties of gelatin; however, they have drawbacks in that the crosslinking agents are potentially toxic. Transglutaminase is an enzyme capable of forming inter- or intra-molecular cross-links in many proteins. The enzyme catalyzes an acyl transfer reaction between the g-carboxamide group of peptide-bound glutamine residues as acyl donors and primary amines as acceptors. When the e-amino group of peptide-bound lysine acts as acyl acceptor, an e-(g-glutamyl) lysine cross-link is formed. This enzyme, now isolated by fermentation, is commercially available, relatively inexpensive, and environmentally safe. We modified gelatins of varying quality with microbial transglutaminase. Gel strengths of low bloom gelatins improved with increasing enzyme concentrations, whereas the gel strengths of higher bloom gelatins either remained the same or decreased with increasing enzyme concentrations. All gelatins gave higher melting points with increasing amounts of enzyme, some even higher than 90ºC. Viscosities, measured at 60ºC and at or near room temperature, increased with increasing enzyme concentrations. The temperature of gelation, as described in the literature, increased not only with the quality of the gelatin but also with increasing enzyme concentrations. Potential applications for this enzyme in by-product utilization and possibly the leather-making process are numerous. En ligne : https://drive.google.com/file/d/1wvenobFOzHHSyBVxHpPVwLjdWfOQ9qxk/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4363
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Code-barres Cote Support Localisation Section Disponibilité 001566 - Périodique Bibliothèque principale Documentaires Disponible Enzymatic modification of hydrolysis products from collagen using a microbial transglutaminase. II. Preparation of films / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 6 (06/2002)
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Titre : Enzymatic modification of hydrolysis products from collagen using a microbial transglutaminase. II. Preparation of films Type de document : texte imprimé Auteurs : Maryann M. Taylor, Auteur ; Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur ; William N. Marmer, Auteur ; Eleanor M. Brown, Auteur Année de publication : 2002 Article en page(s) : p. 225-234 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The use of renewable resources in the production of goods traditionally made from petroleum products has recently gained increasing research interest. Environmental concerns, such as biodegradability and ever increasing landfill fees, could be allayed by use of these products. During the conversion of hides and skins into leather, a high percentage of the original collagen substrate becomes waste. This waste has potential for recycling into useful products. Historically, gelatins (a collagen by-product) have been modified chemically, and the physical properties of these products have been improved. However, because of cost and the toxicity issues associated with some crosslinking chemicals, enzymatically modified products would be highly desirable. Commercial gelatins were treated enzymatically with a microbial transglutaminase, mixed with glycerol as plasticizer, and films were prepared. It was found that the amount of glycerol added affected the mechanical properties, particularly the maximum strain. Increasing the concentration of cross-linking agent gave products with higher tensile strengths that were less soluble in water and had improved water absorption properties. The products resulting from these studies have implications not only in the preparation of edible films and sausage casings, but also in the packaging material market, a market not previously utilized because of poor mechanical properties of gelatin films. En ligne : https://drive.google.com/file/d/1su4LsTGTT8SqZfWaqGbeArqyVz3oJwhB/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4291
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Code-barres Cote Support Localisation Section Disponibilité 001575 - Périodique Bibliothèque principale Documentaires Disponible Enzymatic modification of hydrolysis products from collagen using a microbial transglutaminase. III. Preparation of films with improved mechanical properties / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 11 (11/2003)
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Titre : Enzymatic modification of hydrolysis products from collagen using a microbial transglutaminase. III. Preparation of films with improved mechanical properties Type de document : texte imprimé Auteurs : Maryann M. Taylor, Auteur ; Eleanor M. Brown, Auteur ; William N. Marmer, Auteur ; Cheng-Kung Liu, Auteur Année de publication : 2003 Article en page(s) : p. 435-444 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Previous work from this laboratory demonstrated that films prepared from gelatins that had been enzymatically modified with microbial transglutaminase had improved tensile strength and toughness, were less soluble in water than gelatin alone and had improved hydrophilic properties. In the present study, our goal was to further enhance functional properties of the enzymatically prepared films and at the same time determine if biodegradability is retained. Orienting films has been described as a method to improve mechanical properties. We found that tensile strength, maximum strain, and Young's Modulus improved significantly when orientation took place on either unmodified or crosslinked dry gelatin films or on films that were swollen in water and then were subsequently dried in the strained position. We further demonstrated that the temperature of drying affects mechanical properties; drying at ambient temperature gives products with significantly higher tensile strength and reduced maximum strain over those products that had been dried at a higher temperature. Furthermore, we found that mechanical properties of strained and unstrained films, dried at ambient temperature, will give similar tensile strengths, thus indicating the importance of careful drying in film preparation. Finally, when polyvinyl alcohol was added to the gelatin mixture, films with improved tensile strength and maximum strain were obtained. In all studies, not only was biodegradability demonstrated but it was also found that by enzymatically modifying the gelatin, the resulting products were superior. En ligne : https://drive.google.com/file/d/1M2Qt5WzslSGYHiiFn-Ct8QNDW0aCzLgs/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4166
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Code-barres Cote Support Localisation Section Disponibilité 001593 - Périodique Bibliothèque principale Documentaires Disponible Essential chromium ? / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 10 (10/2003)
PermalinkEvaluation of polymers prepared from gelatin and casein or whey as potential fillers / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CII, N° 4 (04/2007)
PermalinkExploring a role in tanning for the gap region of the collagen fibril : catechin-collagen interactions / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIII, N° 9 (09/2008)
PermalinkExtraction of value added byproducts from the treatment of chromium containing collagenous leather industry waste / Maryann M. Taylor in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 81, N° 1 (01-02/1997)
PermalinkFabrication of composite films based on chitosan and vegetable-tanned collagen fibers crosslinked with genipin / Jie Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVI, N° 10 (10/2021)
PermalinkFunctional properties of hydrolysis products from collagen / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIII, N° 2 (02-03/1998)
PermalinkGenipin -aluminium or -vegetable tannin combinations on hide powder / Keyi Ding in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CII, N° 5 (05/2007)
PermalinkInfluence of pepsin and trypsin on chemical and physical properties of isolated gelatin from chrome shavings / Luisa F. Cabeza in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCII, N° 8 (10/1997)
PermalinkIsolation of protein products from chromium-containing leather waste using two consecutive enzyme and purification of final chromium product : pilot plant studies / Luisa F. Cabeza in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 83, N° 1 (01-02/1999)
PermalinkModel of the helical portion of a type I collagen microfibril / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCII, N° 1 (01/1997)
PermalinkModified collagen hydrolysate, potential for use as a filler for leather / Wuyong Chen in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVI, N° 7 (07/2001)
PermalinkMolecular modeling approach to vegetable tanning : Preliminary results for gallotannin interactions with the collagen microfibril / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVI, N° 5 (05/2011)
PermalinkMolecular modeling of N-terminal telopeptides of bovine type I collagen / Phoebe X. Qi in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 6 (06/2002)
PermalinkMolecular size and conformation of protein recovered from chrome shavings / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXIX, N° 7 (07/1994)
PermalinkMolecular weight distribution and functional properties of enzymatically modified commercial and experimental gelatins / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIX, N° 3 (03/2004)
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