Comparative analysis of the proteomic profile of cattle hides that produce loose and tight leather using in-gel tryptic digestion followed by LC-MS/MS / Catherine Maidment in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 11 (11/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 11 (11/2020) . - p. 399-408 Titre : Comparative analysis of the proteomic profile of cattle hides that produce loose and tight leather using in-gel tryptic digestion followed by LC-MS/MS Type de document : texte imprimé Auteurs : Catherine Maidment, Auteur ; Meekyung Ahn, Auteur ; Rafea Naffa, Auteur ; Trevor Loo, Auteur ; Gillian Norris, Auteur Année de publication : 2020 Article en page(s) : p. 399-408 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagène Cuir lache Cuirs et peaux -- Analyse Cuirs et peaux -- Défauts Cuirs et peaux de bovins Extraction (chimie) Protéines Protéomique La protéomique désigne la science qui étudie les protéomes, c'est-à-dire l'ensemble des protéines d'une cellule, d'un organite, d'un tissu, d'un organe ou d'un organisme à un moment donné et sous des conditions données. Dans la pratique, la protéomique s'attache à identifier de manière globale les protéines extraites d'une culture cellulaire, d'un tissu ou d'un fluide biologique, leur localisation dans les compartiments cellulaires, leurs éventuelles modifications post-traductionnelles ainsi que leur quantité. Elle permet de quantifier les variations de leur taux d'expression en fonction du temps, de leur environnement, de leur état de développement, de leur état physiologique et pathologique, de l'espèce d'origine. Elle étudie aussi les interactions que les protéines ont avec d'autres protéines, avec l'ADN ou l'ARN, ou d'autres substances. La protéomique fonctionnelle étudie les fonctions de chaque protéine. La protéomique étudie enfin la structure primaire, secondaire et tertiaire des protéines. (Wikipedia) Statistique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Looseness is a defect found in leather that reduces its quality by causing a wrinkly appearance in the finished product, resulting in a reduction in its value. Earlier studies on loose leather using microscopy and Raman spectroscopy reported a change in the collagen structure of loose leather. In this study, proteomics was used to investigate the possible molecular causes of looseness in the raw material, the first time such a study has been carried out. Proteins extracted from two regions of raw hide using two different methods were analysed; those taken from the distal axilla, an area prone to looseness, and those taken from the backbone which is less prone to looseness. Analyses using 1DE-LC-MS/MS showed that although the overall collagen concentration was similar in both areas of the hide, the distribution of the different types of collagen differed. Specifically, concentrations of type I collagen, and the collagen-associated proteoglycan decorin were lower in samples taken from the distal axilla, symptomatic of a collagen network with excess space seen for these samples using confocal microscopy. This study suggests a possible link between the molecular components of raw cattle hide and looseness and more importantly between the molecular components of skin and skin defects. There is therefore potential to develop biomarkers for looseness which will enable early preventative action. Note de contenu : - EXPERIMENTAL : chemicals - Sample preparation - Protein extraction - Protein digestion - LC-MS/MS - Protein identification - Statistical analysis - Total collagen concentration - 3D confocal microscopy - RESULTS AND DISCUSSION : Proteomic profiles : a comparison of the extraction methods - Differences between the OSP and DA regions of raw cattle hide - Table 1 : Proteins that are significantly down regulated in the DA DOI : https://doi.org/10.34314/jalca.v115i11.4184 En ligne : https://drive.google.com/file/d/1ve1EQeASe3mqkTpkqz0ZFQG6fgEMbxns/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34846 [article]

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Insights into the molecular composition of the skins and hides used in leather manufacture / Rafea Naffa in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 1 (01/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 1 (01/2019) . - p. 29-36 Titre : Insights into the molecular composition of the skins and hides used in leather manufacture Type de document : texte imprimé Auteurs : Rafea Naffa, Auteur ; Catherine Maidment, Auteur ; Geoff Holmes ; Gillian Norris Année de publication : 2019 Article en page(s) : p. 29-36 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux -- Analyse Cuirs et peaux de bovins Cuirs et peaux de chèvres Cuirs et peaux de daims Cuirs et peaux de moutons Structure moléculaire Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Increasing demand for information about the effects of the beamhouse processes on animal skins and hides led to the need to determine the differences among different animal skins and hides at molecular level which results in significant changes in their strength. This is a comprehensive study of the molecular components of four animal skins commonly used to manufacture shoes, clothing and furniture to identify common indicators of skin strength. First, the strength of each species was assessed using tear strength and the denaturation temperature. Then the concentration of the following molecular compounds: amino acids, natural collagen crosslinks and glycosaminoglycans (GAGs) were determined. Significant differences in their molecular compositions were found particularly the types and amount of the natural collagen crosslinks which are known to be essential for skin strength. We found that sheep skin contained the lowest collagen content and highest GAG concentrations compared to goat and deer skins and cow hide. To the best of our knowledge, this is the first time where the collagen crosslinks of skin and hide of different species are measured and compared. This study shows that different species have different underlying molecular composition of skins and hides resulting in strength differences. This understanding will help to modify the current leather processing protocols to produce stronger leather. Note de contenu : - EXPERIMENTAL : Chemicals & reagents - Preparation of skin samples - Skin thickness measurements - Tear strength of sheep, goat, deer skins and cow hide - Differential scanning calorimetry (DSC) of sheep, goat, deer skins and cow hide - Amino acid extraction from sheep, goat, deer skins and cow hide - Derivatization of amino acids by 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate - Separation of AQC deeivatized amino acids - Extraction and quantitation of glycosaminoglycans in skins - RESULTS AND DISCUSSION : Tear strength of sheep, goat, deer skins and cow hide - Differential scanning calorimetry (DSC) of sheep, goat and deer skins and cow hide - Amino acid composition of sheep, goat and deer skins and cow hide - Collagen I/III ratio in sheep, goat and deer skins and and cow hide - Quantitation of glycosaminoglycans (GAGs) in sheep, goat and deer skins and cow hide - Analysis of crosslinks in sheep, goat and deer skins and cow hide En ligne : https://drive.google.com/file/d/1EPPwJTQrMvg0M1XYcXbJjQzwk94mxEY7/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31551 [article]

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Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS / Yi Zhang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 9 p. Titre : Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS Type de document : texte imprimé Auteurs : Yi Zhang, Auteur ; Rafea Naffa, Auteur ; Christopher J. Garvey, Auteur ; Catherine Maidment, Auteur ; Sujay Prabakar, Auteur Année de publication : 2019 Article en page(s) : 9 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie) Chromatographie en phase liquide Collagène -- Structure Cuirs et peaux Réticulation (polymérisation) Spectrométrie de masse Traceurs radioactifs Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Collagen structure in biological tissues imparts its intrinsic physical properties by the formation of several covalent crosslinks. For the first time, two major crosslinks in the skin dihydroxylysinonorleucine (HLNL) and histidinohydroxymerodesmosine (HHMD), were isotopically labelled and then analysed by liquid-chromatography high-resolution accurate-mass mass spectrometry (LC-HRMS) and small-angle neutron scattering (SANS). The isotopic labelling followed by LC-HRMS confirmed the presence of one imino group in both HLNL and HHMD, making them more susceptible to degrade at low pH. The structural changes in collagen due to extreme changes in the pH and chrome tanning were highlighted by the SANS contrast variation between isotopic labelled and unlabelled crosslinks. This provided a better understanding of the interaction of natural crosslinks with the chromium sulphate in collagen suggesting that the development of a benign crosslinking method can help retain the intrinsic physical properties of the leather. This analytical method can also be applied to study artificial crosslinking in other collagenous tissues for biomedical applications. Note de contenu : - EXPERIMENTAL METHODS : Materials and methods - RESULTS AND DISCUSSION : Characterization of natural crosslinks in skin collagen : isotopic labelling using NaBD4 and mechanism of HHMD formation - Quantification of natural crosslinks in skin collagen : relationship with pH and crosslinking conditions - Structural analysis of skin collagen : interplay between natural and artificial crosslinks - Table 1 : Collagen D-periodicity at different processing stages in control, reduced and labelled skin samples. The D-period decreased for all samples starting from raw to the pickled stage, then increased at the crosslinked stage DOI : https://doi.org/10.1186/s42825-019-0012-x En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0012-x.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36955 [article]

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Raman and ATR-FTIR spectroscopy towards classification of wet blue bovine leather using ratiometric using ratiometric and chemometric analysis / Megha Mehta in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 2 (Année 2020)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 2 (Année 2020) . - 15 p. Titre : Raman and ATR-FTIR spectroscopy towards classification of wet blue bovine leather using ratiometric using ratiometric and chemometric analysis Type de document : texte imprimé Auteurs : Megha Mehta, Auteur ; Rafea Naffa, Auteur ; Catherine Maidment, Auteur ; Geoff Holmes, Auteur ; Mark Waterland, Auteur Année de publication : 2020 Article en page(s) : 15 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse multivariée Cuirs et peaux -- Analyse Cuirs et peaux -- Défauts Cuirs et peaux de bovins Réflexion totale atténuée Spectroscopie Raman Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : There is a substantial loss of value in bovine leather every year due to a leather quality defect known as “looseness”. Data show that 7% of domestic hide production is affected to some degree, with a loss of $35 m in export returns. This investigation is devoted to gaining a better understanding of tight and loose wet blue leather based on vibrational spectroscopy observations of its structural variations caused by physical and chemical changes that also affect the tensile and tear strength. Several regions from the wet blue leather were selected for analysis. Samples of wet blue bovine leather were collected and studied in the sliced form using Raman spectroscopy (using 532 nm excitation laser) and Attenuated Total Reflectance - Fourier Transform InfraRed (ATR-FTIR) spectroscopy. The purpose of this study was to use ATR-FTIR and Raman spectra to classify distal axilla (DA) and official sampling position (OSP) leather samples and then employ univariate or multivariate analysis or both. For univariate analysis, the 1448 cm− 1 (CH2 deformation) band and the 1669 cm− 1 (Amide I) band were used for evaluating the lipid-to-protein ratio from OSP and DA Raman and IR spectra as indicators of leather quality. Curve-fitting by the sums-of-Gaussians method was used to calculate the peak area ratios of 1448 and 1669 cm− 1 band. The ratio values obtained for DA and OSP are 0.57 ± 0.099, 0.73 ± 0.063 for Raman and 0.40 ± 0.06 and 0.50 ± 0.09 for ATR-FTIR. The results provide significant insight into how these regions can be classified. Further, to identify the spectral changes in the secondary structures of collagen, the Amide I region (1600–1700 cm− 1) was investigated and curve-fitted-area ratios were calculated. The 1648:1681 cm− 1 (non-reducing: reducing collagen types) band area ratios were used for Raman and 1632:1650 cm− 1 (triple helix: α-like helix collagen) for IR. The ratios show a significant difference between the two classes. To support this qualitative analysis, logistic regression was performed on the univariate data to classify the samples quantitatively into one of the two groups. Accuracy for Raman data was 90% and for ATR-FTIR data 100%. Both Raman and ATR-FTIR complemented each other very well in differentiating the two groups. As a comparison, and to reconfirm the classification, multivariate analysis was performed using Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA). The results obtained indicate good classification between the two leather groups based on protein and lipid content. Principal component score 2 (PC2) distinguishes OSP and DA by symmetrically grouping samples at positive and negative extremes. The study demonstrates an excellent model for wider research on vibrational spectroscopy for early and rapid diagnosis of leather quality. Note de contenu : - EXPERIMENTAL : Sample preparation - Data acquisition and spectral processing - RESULTS AND DISCUSSION : Peaks of interest - Univariate analysis - Multivariate analysis - Table 1 : Raman and infrared spectroscopic band assignments for Wet Blue leather - Table 2 : Raman band assignments distinguishing loose and tight wet blue leather - Table 3 : Deconvoluted amide I band assignments for protein secondary structures - Table 4 : Confusion matrix for Raman univariate analysis - Table 5 : Confusion matrix for IR univariate analysis - Table 6 : Confusion matrix for the classification of OSP and DA based on the PCA-LDA model DOI : 10.1186/s42825-019-0017-5 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0017-5.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37139 [article]

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