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Articles de revues sur le sujet "Separations of proteins mixture"
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Hassan, Sammer-ul. « Microchip Electrophoresis ». Encyclopedia 1, no 1 (23 décembre 2020) : 30–41. http://dx.doi.org/10.3390/encyclopedia1010006.
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Microchip electrophoresis (MCE) is a miniaturized form of capillary electrophoresis. Electrophoresis is a common technique to separate macromolecules such as nucleic acids (DNA, RNA) and proteins. This technique has become a routine method for DNA size fragmenting and separating protein mixtures in most laboratories around the world. The application of higher voltages in MCE achieves faster and efficient electrophoretic separations.
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Zagst, Holger, Christin Elgert, Sönke Behrends et Hermann Wätzig. « Combination of strong anion exchange liquid chromatography with microchip capillary electrophoresis sodium dodecyl sulfate for rapid two-dimensional separations of complex protein mixtures ». Analytical and Bioanalytical Chemistry 414, no 4 (6 décembre 2021) : 1699–712. http://dx.doi.org/10.1007/s00216-021-03797-4.
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AbstractTwo-dimensional separations provide a simple way to increase the resolution and peak capacity of complex protein separations. The feasibility of a recently developed instrumental approach for two-dimensional separations of proteins was evaluated. The approach is based on the general principle of two-dimensional gel electrophoresis. In the first dimension, semi-preparative strong anion exchange high-performance liquid chromatography is utilized and fractions are collected by means of a fraction collector. They are subsequently analyzed in the second dimension with microchip capillary electrophoresis sodium dodecyl sulfate. Microchip capillary electrophoresis provides the necessary speed (approximately 1 min/fraction) for short analysis. In this study, three different samples were investigated. Different constructs of soluble guanylyl cyclase were expressed in Sf9-cells using the baculovirus expression system. Cell lysates were analyzed and the resulting separations were compared. In our experimental setup, the soluble guanylyl cyclase was identified among hundreds of other proteins in these cell lysates, indicating its potential for screening, process control, or analysis. The results were validated by immunoblotting. Samples from Chinese hamster ovary cell culture before and after a purification step were investigated and approximately 9% less impurities could be observed. The separation patterns obtained for human plasma are closely similar to patterns obtained with two-dimensional gel electrophoresis and a total of 218 peaks could be observed. Overall, the approach was well applicable to all samples and, based on these results, further directions for improvements were identified. Graphical abstract .
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Pathak, Karishma. « Preliminary Phytochemical Screening and Thin Layer Chromatography of Different Solvent Extract of Bark of Ficus lacor (Pakar) ». Journal of Drug Discovery and Development 5, no 1 (24 février 2022) : 12–16. http://dx.doi.org/10.24321/2581.6861.202102.
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Medicinal plant used for many disease treatments in the form of extract. This study performed for confirmation the different solvents extract such as alcoholic, hydroalcoholic, aqueous. An herbal plant Ficus lacor uses different parts for treating various diseases such a seed, leaves, fruits, roots, berries and bark. In this research perform the Phytochemical activities and also perform thin layer chromatography of extract were performed at SHEAT college laboratory. Phytochemical screening resultant a various chemical constituents are found such as: Carbohydrates, Tannins and Phenolic, Alkaloids, Anthraquinones glycoside, Amino Acid, proteins, Reducing Sugar. Thin layer chromatography for analyzed the mixture by separations of a compounds this test are successfully performed for the expected out come as antiulcer activity.
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McDonald, W. Hayes, et John R. Yates. « Shotgun Proteomics and Biomarker Discovery ». Disease Markers 18, no 2 (2002) : 99–105. http://dx.doi.org/10.1155/2002/505397.
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Coupling large-scale sequencing projects with the amino acid sequence information that can be gleaned from tandem mass spectrometry (MS/MS) has made it much easier to analyze complex mixtures of proteins. The limits of this “shotgun” approach, in which the protein mixture is proteolytically digested before separation, can be further expanded by separating the resulting mixture of peptides prior to MS/MS analysis. Both single dimensional high pressure liquid chromatography (LC) and multidimensional LC (LC/LC) can be directly interfaced with the mass spectrometer to allow for automated collection of tremendous quantities of data. While there is no single technique that addresses all proteomic challenges, the shotgun approaches, especially LC/LC-MS/MS-based techniques such as MudPIT (multidimensional protein identification technology), show advantages over gel-based techniques in speed, sensitivity, scope of analysis, and dynamic range. Advances in the ability to quantitate differences between samples and to detect for an array of post-translational modifications allow for the discovery of classes of protein biomarkers that were previously unassailable.
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Sirkisoon, Leona R., Honest C. Makamba, Shingo Saito et Christa L. Colyer. « Carbon Dot-Mediated Capillary Electrophoresis Separations of Metallated and Demetallated Forms of Transferrin Protein ». Molecules 24, no 10 (18 mai 2019) : 1916. http://dx.doi.org/10.3390/molecules24101916.
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Carbon dots (CDs) are fluorescent nanomaterials used extensively in bioimaging, biosensing and biomedicine. This is due in large part to their biocompatibility, photostability, lower toxicity, and lower cost, compared to inorganic quantum dots or organic dyes. However, little is known about the utility of CDs as separation adjuvants in capillary electrophoresis (CE) separations. CDs were synthesized in-house according to a ‘bottom-up’ method from citric acid or other simple carbon precursors. To demonstrate the applicability of CDs as separation adjuvants, mixtures of holo- (metallated) and apo- (demetallated) forms of transferrin (Tf, an iron transport protein) were analyzed. In the absence of CDs, the proteins were not resolved by a simple CE method; however, upon addition of CDs to the separation buffer, multiple forms of Tf were resolved indicating that CDs are valuable tools to facilitate the separation of analytes by CE. CE parameters including sample preparation, buffer identity, ionic strength, pH, capillary inside diameter, and temperature were optimized. The results suggest that dots synthesized from citric acid provide the best resolution of various different forms of Tf and that CDs are versatile and promising tools to improve current electrophoretic separation methods, especially for metalloprotein analysis.
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Jun, Sei-Hwan, et Eli Ruckenstein. « Separation of a Multicomponent Mixture of Proteins by Potential Barrier Chromatography (PBC) ». Separation Science and Technology 21, no 2 (avril 1986) : 111–38. http://dx.doi.org/10.1080/01496398608058369.
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Hasan, Farhana, Punprabhashi Vidanapathirana, Susmita Das, Vivian E. Fernand, Noureen Siraj, Jack N. Losso et Isiah M. Warner. « Ionic liquids as buffer additives in ionic liquid-polyacrylamide gel electrophoresis separation of mixtures of low and high molecular weight proteins ». RSC Advances 5, no 85 (2015) : 69229–37. http://dx.doi.org/10.1039/c5ra11559k.
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Zaccheria, Federica, Matteo Mariani, Nicola Scotti, Rinaldo Psaro et Nicoletta Ravasio. « Catalytic upgrading of lactose : a rest raw material from the dairy industry ». Green Chemistry 19, no 8 (2017) : 1904–10. http://dx.doi.org/10.1039/c7gc00741h.
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Lactose, a residue from the separation of high value-added proteins from whey, was converted into an equimolar mixture of sorbitol and dulcitol through a one-step cascade hydrolysis plus hydrogenation process.
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Guerrera, Ida Chiara, et Oliver Kleiner. « Application of Mass Spectrometry in Proteomics ». Bioscience Reports 25, no 1-2 (4 février 2005) : 71–93. http://dx.doi.org/10.1007/s10540-005-2849-x.
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Mass spectrometry has arguably become the core technology in proteomics. The application of mass spectrometry based techniques for the qualitative and quantitative analysis of global proteome samples derived from complex mixtures has had a big impact in the understanding of cellular function. Here, we give a brief introduction to principles of mass spectrometry and instrumentation currently used in proteomics experiments. In addition, recent developments in the application of mass spectrometry in proteomics are summarised. Strategies allowing high-throughput identification of proteins from highly complex mixtures include accurate mass measurement of peptides derived from total proteome digests and multidimensional peptide separations coupled with mass spectrometry. Mass spectrometric analysis of intact proteins permits the characterisation of protein isoforms. Recent developments in stable isotope labelling techniques and chemical tagging allow the mass spectrometry based differential display and quantitation of proteins, and newly established affinity procedures enable the targeted characterisation of post-translationally modified proteins. Finally, advances in mass spectrometric imaging allow the gathering of specific information on the local molecular composition, relative abundance and spatial distribution of peptides and proteins in thin tissue sections.
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Haribabu, Malavika, Dave E. Dunstan, Gregory J. O. Martin, Malcolm R. Davidson et Dalton J. E. Harvie. « Simulating the ultrafiltration of whey proteins isolate using a mixture model ». Journal of Membrane Science 613 (novembre 2020) : 118388. http://dx.doi.org/10.1016/j.memsci.2020.118388.
Texte intégralThèses sur le sujet "Separations of proteins mixture"
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Goebel, Lisa Karen. « Electrokinetic separations involving surfactants and proteins ». Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/39443.
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Methods for the analysis of surfactants and proteins by Capillary Electrophoresis (CE) were investigated. Several modifications of the system to achieve detection and separation of these analytes were examined. These modifications included buffer additives, sample additives and surface treatment and modification of the fused silica capillary.
For the analysis of anionic surfactants, the addition of an anionic IN absorbing compound to the buffer was investigated to achieve indirect detection of the non-absorbing surfactants. The effect on detection sensitivity and separation efficiency of the absorbing ion was examined. These parameters were affected by differences in the electrophoretic mobilities of the analytes in comparison to the absorbing ion. The use of organic modifiers was also investigated to minimize micelle formation of the surfactants which leads to zone spreading.
For the analysis of serum and urine proteins, the use of high pH buffers was investigated to minimize solute/capillary surface interactions and achieve separation. At high pH's the proteins are negatively charged; therefore, they should be repelled by the negatively charged fused silica surface. To improve reproducibility of migration times of the proteins the addition of polyvinyl alcohol to the sample was also investigated. The polyvinyl alcohol improved reproducibility by reversibly covering the active sites on the capillary surface to minimize protein interactions. Migration time reproducibility was also improved by optimizing the capillary cleaning procedure. Lastly, the addition of methyl cellulose to the buffer to work as a dynamic molecular sieving medium was investigated to improve resolution.
Analyte/ capillary surface interactions are a major limitation in CE especially for the analyses of proteins. The use of coated capillaries to eliminate these interactions has been widely investigated. However, reproducibility and degree of surface deactivation with these coating can be poor. In this work hydrothennal treatment of the fused silica capillary surface prior to deactivation was examined. Hydrothennal treatment was used to produce a homogenous surface prior to coating which leads to the production of more highly deactivated, reproducible columns. The effects of the treatment were studied by coating the surface with a silane and examining the influence of the coating on electroosmotic flow and analyte adsorption.Ph. D.
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Parmar, Avanish Singh. « Probing interactions and phase separations of proteins, colloids and polymers with light scattering ». [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002977.
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Witkowski, Thomas, Rainer Backofen et Axel Voigt. « The influence of membrane bound proteins on phase separation and coarsening in cell membranes ». Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-139226.
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A theoretical explanation of the existence of lipid rafts in cell membranes remains a topic of lively debate. Large, micrometer sized rafts are readily observed in artificial membranes and can be explained using thermodynamic models for phase separation and coarsening. In live cells such domains are not observed and various models are proposed to describe why the systems do not coarsen. We review these attempts critically and show within a phase field approach that membrane bound proteins have the potential to explain the different behaviour observed in vitro and in vivo. Large scale simulations are performed to compute scaling laws and size distribution functions under the influence of membrane bound proteins and to observe a significant slow down of the domain coarsening at longer times and a breakdown of the self-similarity of the size-distribution functionDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Witkowski, Thomas, Rainer Backofen et Axel Voigt. « The influence of membrane bound proteins on phase separation and coarsening in cell membranes ». Royal Society of Chemistry, 2012. https://tud.qucosa.de/id/qucosa%3A27814.
Texte intégralRésumé :
A theoretical explanation of the existence of lipid rafts in cell membranes remains a topic of lively debate. Large, micrometer sized rafts are readily observed in artificial membranes and can be explained using thermodynamic models for phase separation and coarsening. In live cells such domains are not observed and various models are proposed to describe why the systems do not coarsen. We review these attempts critically and show within a phase field approach that membrane bound proteins have the potential to explain the different behaviour observed in vitro and in vivo. Large scale simulations are performed to compute scaling laws and size distribution functions under the influence of membrane bound proteins and to observe a significant slow down of the domain coarsening at longer times and a breakdown of the self-similarity of the size-distribution function.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Fernando, Ganga Sripali. « DEVELOPMENT AND OPTIMIZATION OF ON-PROBE AFFINTY CAPTURE (OPAC) MALDI MASS SPECTROMETRY FOR THE FRACTIONATION AND ANALYSIS OF COMPLEX PROTEIN MIXTURES ». OpenSIUC, 2009. https://opensiuc.lib.siu.edu/dissertations/68.
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A high throughput proteomic analysis method is described here that uses more economically favorable, easily manufactured probe surface that can be directly incorporated on the MALDI target. On-Probe Affinity Capture (OPAC) MALDI is a method that uses the RF pulsed plasma modified target surfaces for the protein purification, separation and identification all on the same single probe and one of the highest advantage of this method is the number of different experiments that can be carried out simultaneously using the intelligent design of the probe. The new design of the OPAC probe presented in this dissertation gives the ability to perform about 100 different experiments on one single MALDI target. These OPAC probes can be used for the fractionation and analysis of proteins from complex biologically derived samples. The separated proteins can be identified on the OPAC probe using it directly as the MALDI target and selecting a proper elution solution that depends on the chemistry of the OPAC probe, the surface bound proteins can be eluted and incorporated into the matrix crystal. This dissertation focuses mainly on developing this method for analysis of different samples. A tryptic digest of a single protein was separated and identified by submitting the peak lists to MASCOT database search and the sequence coverage obtained before and after fractionation has been compared. Then a mixture of tryptic peptides of five different known proteins were fractionated on OPAC surfaces and the identification of proteins obtained was compared before and after fractionation. Further developing this technique, biologically derived mixtures of proteins from two different well studied sources have been analyzed using OPAC-MALDI. Escherichia coli bacterial proteome was digested and fractionated and the peptides were studied using De Novo sequencing method and their affinity fractionation behavior is confirmed by calculating the iso electric point (pI) and the hydrophobicity of the predicted peptide sequence. Synechosystis sp PCC 6803 was cultured and the protein extracts were prepared for the OPAC studies. The clear fractionated of this mixture was observed and the amount of information derived after fractionation is found to be significantly higher than the unfractionated sample. Taking a slightly different approach, a phosphoprotein binding OPAC probe was prepared using commercially available poly(methyl methacrylate) (PMMA) film. The hydrolyzed PPMA films were reacted with CuCl2 solution to incorporate metal ions on the surface by electrostatic interaction, which then facilitates the phosphoprotein binding on the OPAC probe. This was demonstrated using a binary mixture of commercially available peptides and fractionating the mixture on Cu-impregnated PMMA film. Finally, in a collaborative work, the possibility of increased surface binding capacity was explored by using a synthetic organic nanosponge surface that expands and collapses due to change of pH. These brush polymers were prepared by Dyer group and a binary mixture of peptides were fractionated and analyzed by MALDI MS.
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Sahasrabuddhe, Aniruddha. « Characterization of Proteins and Protein Complexes by Online Chromatographic Separations and Direct Infusion Native Mass Spectrometry ». The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1515171055447523.
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Van, der Mijnsbrugge Adriaan. « Mechano-chemical model study of the mixing process of water/flour mixtures in the context of the industrial wheat gluten-starch separation process ». Thesis, Montpellier, SupAgro, 2015. http://www.theses.fr/2015NSAM0022.
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Le processus de séparation gluten-amidon est un des éléments clés du procédé de fractionnement de la farine de blé, pour la production d'amidon, de produits dérivés de l'amidon et de gluten de blé. Le procédé industriel comprend une étape de malaxage du mélange farine/eau, une étape de dilution de la pâte obtenue et enfin des opérations de séparation gluten-amidon par tamisage ou centrifugation. Le procédé industriel est très consommatoire en eau, et plusieurs flux d'eau sont recyclés des étapes situés en aval du procédé vers les étapes en amont comme la préparation et la dilution de la pâte. L'objective de cette étude était d'étudier l'impact de ces flux d'eau recyclés sur l'agglomération du gluten, et d'identifier les principaux paramètres du procédé qui influencent le rendement d'extraction du gluten. Basé sur l'échantillonnage de plusieurs flux d'eau de différentes usines, un composant clé de ces flux d'eau recyclée a été identifié. Les mécanismes de développement de la pâte ont été étudiés à l'échelle laboratoire en utilisant un mélangeur planétaire (P600). La présence du composant au niveau de l'étape de préparation de la pâte retarde sa cinétique de développement et augmente l'énergie mécanique à fournir pour le développement. A l'échelle moléculaire ce composant ralentit la dépolymérisation des polymères de gluténine insolubles dans le SDS (UPP) de la farine lors du malaxage de la pâte. L'agglomération du gluten est contrariée par la présence de ce composé que ce soit au moment de la préparation de la pâte ou de sa dilution. Au cours de l'étape de dilution ce composé modifie chimiquement les arabinoxylanes de la farine, ce qui a un effet négatif très direct sur la capacité d'agglomération des protéines du gluten. Un paramètre de conduite de l'opération de malaxage a été identifié qui rend compte de la capacité d'agglomération du gluten (rendement du procédé) et de la distribution en taille des macromolécules de gluténines présentent dans le gluten extrait. Ce dernier paramètre est également sous l'influence de la composition en gluténines, codées par le locus Glu-1D du génome du bléThe gluten-starch separation process is a key part of an industrial wheat fractionation plant, producing starch, starch-derived products, and vital wheat gluten. The industrial process consists of an initial flour hydration and dough mixing phase, a dough dilution step, followed by a gluten-starch separation by sieving or centrifugation. As this process is highly water consuming, several water streams are recycled from downstream unit operation of the process back upstream, to stages such as dough preparation and dough dilution. The aim of the present study was to investigate the impact of these recycled water streams on gluten agglomeration, and provide a further insight on the main process parameters influencing the gluten extraction yield. Based on the sampling of several water streams of different industrial plants, a key compound of these recycled water streams was characterized. A lab scale planetary mixer was used to study the dough development mechanisms. The presence of this compound at the dough preparation stage delayed dough development, as it increased the energy demand of the dough. On a molecular scale this constituent induced a delay of the depolymerization of SDS-insoluble glutenin (UPP) during dough mixing. Gluten agglomeration is impeded by this compound, both when present at the stage of dough preparation and dough dilution. The presence of this compound at the dough dilution stage chemically modified the flour arabinoxylans, impairing gluten agglomeration. A mixing parameter directly influencing both the molecular distribution of extracted gluten, as well as their agglomerating capacity, was proposed. The evolution of the molecular distribution of the extracted gluten with this mixing parameter was shown to be influenced by the wheat its glutenin composition, coded by the Glu-1D locus of the wheat genome
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Tambosi, Reem. « Stress and toxicity of metal in photosynthetic bacteria : multi-scale study of the effects and the targets of metal ions and nanoparticles Silver and Copper Acute Effects on Membrane Proteins and Impact on Photosynthetic and Respiratory Complexes in Bacteria Silver Effect on Bacterial Cell Membrane Structure Investigated by Atomic Force and Scanning Electron Microscopes Cadmium and Copper Cross-tolerance. Cu+ alleviates Cd2+ toxicity, and both cations target heme and chlorophyll biosynthesis pathway in Rubrivivax gelatinosus Additive effects of metal excess and superoxide, a highly toxic mixture in bacteria ». Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL070.
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L’usage intensif des métaux et des ions métalliques dans l'industrie et l'agriculture représente une menace sérieuse pour l'environnement et pour tous les êtres vivants en raison de la toxicité aiguë de ces ions. Cependant, cela peut aussi être un outil prometteur. En effet, les ions comme les nanoparticules d'argent sont très utilisés dans diverses applications médicales, industrielles et sanitaires. L'effet antimicrobien de ces nanoparticules est en partie lié aux ions Ag⁺ libérés et à leur capacité à interagir avec les membranes bactériennes. L'objectif de ce projet est d'étudier l'interaction entre un objet biologique (les bactéries) et des objets physiques (métaux), pour comprendre l'impact des métaux sous différentes formes (ions, nanoparticules et nanostructures) sur les cellules bactériennes en utilisant différentes approches: de physiologie, biochimie, génétique et de biologie cellulaire. Nous avons utilisé comme modèles biologiques, principalement la bactérie photosynthétique pourpre Rubrivivax (R.) gelatinosus, mais aussi Escherichia coli; et pour les objets physiques, nous avons utilisé l'argent comme métal principal mais aussi d'autres métaux (cuivre, cadmium et nickel) à titre de comparaison. Les principaux objectifs de ce travail sont: 1- d'étudier l'impact et les mécanismes de toxicité de ces ions métalliques / NPs sur les métabolismes bactériens respiratoire et photosynthétique. 2- Identifier des gènes bactériens impliqués dans la réponse à un excès d'ions Ag⁺. 3- Etudier l'internalisation et l'interaction des ions métalliques et des NP au sein des membranes biologiques. Ainsi, nous avons pu identifier, à la fois in vitro et in vivo, des cibles spécifiques d'ions Ag⁺ et Cu²⁺ dans la membrane des bactéries. Cela inclut des complexes impliqués dans la photosynthèse, mais également des complexes de la chaine respiratoire. Il a été démontré que les ions Ag⁺ et Cu²⁺ ciblent spécifiquement une bactériochlorophylle exposée au solvant dans les antennes de collecte de lumière du photosystème de la bactérie. Ceci présente également, à notre connaissance, la première preuve directe de dommages induits par des ions Ag⁺ sur les protéines membranaires impliquées dans ces métabolismes. Par ailleurs, nous avons également réalisé une étude comparative par microscopie (AFM/ MEB) de l'effet de l'Ag⁺ en solution ou des Ag-NPs synthétisés dans notre laboratoire, sur la morphologie des cellules bactériennesThe extensive use of metal ions in industry and agriculture represents a serious threat to the environment and to all living being because of the acute toxicity of these ions. However, it can also be a promising tool, silver ions and nanoparticles are some of the most widely used metals in various industrial and health applications. The antimicrobial effect of these nanoparticles is in part related to the released Ag⁺ ions and their ability to interact with bacterial membranes. The goal of this project is to study the interaction between biological subject (the bacteria) and physical objects (metals), and more specifically to understand the impact of metals in different forms (ions, nanoparticles and nanostructures) on the growth of the bacterial cells using different approaches : physiology, biochemistry, genetics and cell biology. We used as biological models, principally the purple photosynthetic bacterium Rubrivivax (R.) gelatinosus, but also Escherichia coli; and for physical objects, we used silver as main metal but also other metals (copper, cadmium and nickel) for comparison. The main objectives are: 1- to study the impact and the mechanisms of toxicity of these metallic ions/NPs on the bacterial respiratory and photosynthesis metabolisms. 2- To identify the bacterial genes involved in response to excess silver. 3- To study the internalization and interaction of metals ions and NPs within biological membranes. The results showed that we were able to identify, both in vitro and in vivo, specific targets of Ag⁺ and Cu²⁺ ions within the membrane of bacteria. This include complexes involved in photosynthesis, but also complexes involved in respiration. Ag⁺ and Cu²⁺ were shown to specificaly target a solvent exposed bacteriochlorophyll in the light harvesting antennae of the photosystem. This also presents, in our knowledge, the first direct evidence of silver ions damages to membrane proteins involved in these metabolisms. We also carried out a microscopy (AFM/ SEM) comparative study of the effect of Ag⁺ ions or Ag-NPs synthesized in our laboratory, on the bacterial cell morphology
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Moreira, Ana Sofia Pereira. « Study of modifications induced by thermal and oxidative treatment in oligo and polysaccharides of coffee by mass spectrometry ». Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17074.
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Doutoramento em BioquímicaOs polissacarídeos são os componentes maioritários dos grãos de café verde e torrado e da bebida de café. Os mais abundantes são as galactomananas, seguindo-se as arabinogalactanas. Durante o processo de torra, as galactomananas e arabinogalactanas sofrem modificações estruturais, as quais estão longe de estar completamente elucidadas devido à sua diversidade e à complexidade estrutural dos compostos formados. Durante o processo de torra, as galactomananas e arabinogalactanas reagem com proteínas, ácidos clorogénicos e sacarose, originando compostos castanhos de alto peso molecular contendo nitrogénio, designados de melanoidinas. As melanoidinas do café apresentam diversas atividades biológicas e efeitos benéficos para a saúde. No entanto, a sua estrutura exata e os mecanismos envolvidos na sua formação permanecem desconhecidos, bem como a relação estrutura-atividade biológica. A utilização de sistemas modelo e a análise por espectrometria de massa permitem obter uma visão global e, simultaneamente, detalhada das modificações estruturais nos polissacarídeos do café promovidas pela torra, contribuindo para a elucidação das estruturas e mecanismos de formação das melanoidinas. Com base nesta tese, oligossacarídeos estruturalmente relacionados com a cadeia principal das galactomananas, (β1→4)-Dmanotriose (Man3), e as cadeias laterais das arabinogalactanas, (α1→5)-Larabinotriose (Ara3), isoladamente ou em misturas com ácido 5-Ocafeoilquínico (5-CQA), o ácido clorogénico mais abundante nos grãos de café verde, e péptidos compostos por tirosina e leucina, usados como modelos das proteínas, foram sujeitos a tratamento térmico a seco, mimetizando o processo de torra. A oxidação induzida por radicais hidroxilo (HO•) foi também estudada, uma vez que estes radicais parecem estar envolvidos na modificação dos polissacarídeos durante a torra. A identificação das modificações estruturais induzidas por tratamento térmico e oxidativo dos compostos modelo foi feita por estratégias analíticas baseadas principalmente em espectrometria de massa, mas também em cromatografia líquida. A cromatografia de gás foi usada na análise de açúcares neutros e ligações glicosídicas. Para validar as conclusões obtidas com os compostos modelo, foram também analisadas amostras de polissacarídeos do café obtidas a partir de resíduo de café e café instantâneo. Os resultados obtidos a partir dos oligossacarídeos modelo quando submetidos a tratamento térmico (seco), assim como à oxidação induzida por HO• (em solução), indicam a ocorrência de despolimerização, o que está de acordo com estudos anteriores que reportam a despolimerização das galactomananas e arabinogalactanas do café durante a torra. Foram ainda identificados outros compostos resultantes da quebra do anel de açúcares formados durante o tratamento térmico e oxidativo da Ara3. Por outro lado, o tratamento térmico a seco dos oligossacarídeos modelo (individualmente ou quando misturados) promoveu a formação de oligossacarídeos com um maior grau de polimerização, e também polissacarídeos com novos tipos de ligações glicosídicas, evidenciando a ocorrência de polimerização através reações de transglicosilação não enzimática induzidas por tratamento térmico a seco. As reações de transglicosilação induzidas por tratamento térmico a seco podem ocorrer entre resíduos de açúcares provenientes da mesma origem, mas também de origens diferentes com formação de estruturas híbridas, contendo arabinose e manose como observado nos casos dos compostos modelo usados. Os resultados obtidos a partir de amostras do resíduo de café e de café instantâneo sugerem a presença de polissacarídeos híbridos nestas amostras de café processado, corroborando a ocorrência de transglicosilação durante o processo de torra. Além disso, o estudo de misturas contendo diferentes proporções de cada oligossacarídeo modelo, mimetizando regiões do grão de café com composição distinta em polissacarídeos, sujeitos a diferentes períodos de tratamento térmico, permitiu inferir que diferentes estruturas híbridas e não híbridas podem ser formadas a partir das arabinogalactanas e galactomananas, dependendo da sua distribuição nas paredes celulares do grão e das condições de torra. Estes resultados podem explicar a heterogeneidade de estruturas de melanoidinas formadas durante a torra do café. Os resultados obtidos a partir de misturas modelo contendo um oligossacarídeo (Ara3 ou Man3) e 5-CQA sujeitas a tratamento térmico a seco, assim como de amostras provenientes do resíduo de café, mostraram a formação de compostos híbridos compostos por moléculas de CQA ligadas covalentemente a um número variável de resíduos de açúcar. Além disso, os resultados obtidos a partir da mistura contendo Man3 e 5-CQA mostraram que o CQA atua como catalisador das reações de transglicosilação. Por outro lado, nas misturas modelo contendo um péptido, mesmo contendo também 5-CQA e sujeitas ao mesmo tratamento, observou-se uma diminuição na extensão das reações transglicosilação. Este resultado pode explicar a baixa extensão das reações de transglicosilação não enzimáticas durante a torra nas regiões do grão de café mais ricas em proteínas, apesar dos polissacarídeos serem os componentes maioritários dos grãos de café. A diminuição das reações de transglicosilação na presença de péptidos/proteínas pode dever-se ao facto de os resíduos de açúcares redutores reagirem preferencialmente com os grupos amina de péptidos/proteínas por reação de Maillard, diminuindo o número de resíduos de açúcares redutores disponíveis para as reações de transglicosilação. Além dos compostos já descritos, uma diversidade de outros compostos foram formados a partir dos sistemas modelo, nomeadamente derivados de desidratação formados durante o tratamento térmico a seco. Em conclusão, a tipificação das modificações estruturais promovidas pela torra nos polissacarídeos do café abre o caminho para a compreensão dos mecanismos de formação das melanoidinas e da relação estrutura-atividade destes compostos.
Polysaccharides are the major components of green and roasted coffee beans, and coffee brew. The most abundant ones are galactomannans, followed by arabinogalactans. During the roasting process, galactomannans and arabinogalactans undergo structural modifications that are far to be completely elucidated due to their diversity and complexity of the compounds formed. During the roasting process, galactomannans and arabinogalactans react with proteins, chlorogenic acids, and sucrose, originating high molecular weight brown compounds containing nitrogen, known as melanoidins. Several biological activities and beneficial health effects have been attributed to coffee melanoidins. However, their exact structures and the mechanisms involved in their formation remain unknown, as well as the structure-biological activity relationship. The use of model systems and mass spectrometry analysis allow to obtain an overall view and, simultaneously, detailed, of the structural modifications in coffee polysaccharides promoted by roasting, contributing to the elucidation of the structures and formation mechanisms of melanoidins. Based on this thesis, oligosaccharides structurally related to the backbone of galactomannans, (β1→4)-D-mannotriose, and the side chains of arabinogalactans, (α1→5)-Larabinotriose, alone or in mixtures with 5-O-caffeoylquinic acid, the most abundant chlorogenic acid in green coffee beans, and dipeptides composed by tyrosine and leucine, used as models of proteins, were submitted to dry thermal treatments, mimicking the coffee roasting process. The oxidation induced by hydroxyl radicals (HO•) was also studied, since these radicals seem to be involved in the modification of the polysaccharides during roasting. The identification of the structural modifications induced by thermal and oxidative treatment of the model compounds was performed mostly by mass spectrometry-based analytical strategies, but also using liquid chromatography. Gas chromatography was used in the analysis of neutral sugars and glycosidic linkages. To validate the conclusions achieved with the model compounds, coffee polysaccharide samples obtained from spent coffee grounds and instant coffee were also analysed. The results obtained from the model oligosaccharides when submitted to thermal treatment (dry) or oxidation induced by HO• (in solution) indicate the occurrence of depolymerization, which is in line with previous studies reporting the depolymerization of coffee galactomannans and arabinogalactans during roasting. Compounds resulting from sugar ring cleavage were also formed during thermal treatment and oxidative treatment of Ara3. On the other hand, the dry thermal treatment of the model oligosaccharides (alone or when mixed) promoted the formation of oligosaccharides with a higher degree of polymerization, and also polysaccharides with new type of glycosidic linkages, evidencing the occurrence of polymerization via non-enzymatic transglycosylation reactions induced by dry thermal treatment. The transglycosylation reactions induced by dry thermal treatment can occur between sugar residues from the same origin, but also of different origins, with formation of hybrid structures, containing arabinose and mannose in the case of the model compounds used. The results obtained from spent coffee grounds and instant coffee samples suggest the presence of hybrid polysaccharides in these processed coffee samples, corroborating the occurrence of transglycosylation during the roasting process. Furthermore, the study of mixtures containing different proportions of each model oligosaccharide, mimicking coffee bean regions with distinct polysaccharide composition, subjected to different periods of thermal treatment, allowed to infer that different hybrid and non-hybrid structures may be formed from arabinogalactans and galactomannans, depending on their distribution in the bean cell walls and on roasting conditions. These results may explain the heterogeneity of melanoidins structures formed during coffee roasting. The results obtained from model mixtures containing an oligosaccharide (Ara3 or Man3) and 5-CQA and subjected to dry thermal treatment, as well as samples derived from spent coffee grounds, showed the formation of hybrid compounds composed by CQA molecules covalently linked to a variable number of sugar residues. Moreover, the results obtained from the mixture containing Man3 and 5-CQA showed that CQA acts as catalyst of transglycosylation reactions. On the other hand, in the model mixtures containing a peptide, even if containing 5-CQA and subjected to the same treatment, it was observed a decrease in the extent of transglycosylation reactions. This outcome can explain the low extent of non-enzymatic transglycosylation reactions during roasting in coffee bean regions enriched in proteins, although polysaccharides are the major components of the coffee beans. The decrease of transglycosylation reactions in the presence of peptides/proteins can be related with the preferential reactivity of reducing residues with the amino groups of peptides/proteins by Maillard reaction, decreasing the number of reducing residues available to be directly involved in the transglycosylation reactions. In addition to the compounds already described, a diversity of other compounds were formed from model systems, namely dehydrated derivatives formed during dry thermal treatment. In conclusion, the identification of the structural modifications in coffee polysaccharides promoted by roasting pave the way to the understanding of the mechanisms of formation of melanoidins and structure-activity relationship of these compounds.
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MENDIETHA, Martha Elena. « New methods for separations of proteins mixtures in capillary electrophoresis and for detection of "low-abundance" proteome ». Doctoral thesis, 2008. http://hdl.handle.net/11562/337634.
Texte intégralLivres sur le sujet "Separations of proteins mixture"
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Gupta, Munishwar Nath, dir. Methods for Affinity-Based Separations of Enzymes and Proteins. Basel : Birkhäuser Basel, 2002. http://dx.doi.org/10.1007/978-3-0348-8127-2.
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Nath, Gupta Munishwar, dir. Methods for affinity-based separations of enzymes and proteins. Basel : Birkhäuser Verlag, 2002.
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Neil, Barnes, dir. Electrophoresis in practice : A guide to methods and applications of DNA and protein separations. 3e éd. Weinheim : Wiley-VCH, 2001.
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Neil, Barnes, dir. Electrophoresis in practice : A guide to methods and applications of DNA and protein separations. 2e éd. Weinheim : VCH, 1997.
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Roe, Simon, dir. Protein Purification Techniques. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780199636747.001.0001.
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Proteins are an integral part of molecular and cellular structure and function and are probably the most purified type of biological molecule. In order to elucidate the structure and function of any protein it is first necessary to purify it. Protein purification techniques have evolved over the past ten years with improvements in equipment control, automation, and separation materials, and the introduction of new techniques such as affinity membranes and expanded beds. These developments have reduced the workload involved in protein purification, but there is still a need to consider how unit operations linked together to form a purification strategy, which can be scaled up if necessary. The two Practical Approach books on protein purification have therefore been thoroughly updated and rewritten where necessary. The core of both books is the provision of detailed practical guidelines aimed particularly at laboratory scale purification. Information on scale-up considerations is given where appropriate. The books are not comprehensive but do cover the major laboratory techniques and common sources of protein. Protein Purification Techniques focuses on unit operations and analytical techniques. It starts with an overview of purification strategy and then covers initial extraction and clarification techniques. The rest of the book concentrates on different purification methods with the emphasis being on chromatography. The final chapter considers general scale-up considerations. Protein Purification Applications describes purification strategies from common sources: mammalian cell culture, microbial cell culture, milk, animal tissue, and plant tissue. It also includes chapters on purification of inclusion bodies, fusion proteins, and purification for crystallography. A purification strategy that can produce a highly pure single protein from a crude mixture of proteins, carbohydrates, lipids, and cell debris to is a work of art to be admired. These books (available individually or as a set)are designed to give the laboratory worker the information needed to undertake the challenge of designing such a strategy.
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Gupta, Munishwar N. Methods for Affinity-Based Separations of Enzymes and Proteins. Birkhauser Verlag, 2013.
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Gupta, Munishwar N. Methods for Affinity Based Separations for Enzymes and Proteins. Birkhäuser Basel, 2002.
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Westermeier, Reiner. Electrophoresis in Practice : A Guide to Methods and Applications of DNA and Protein Separations. Wiley & Sons, Incorporated, John, 2016.
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Westermeier, Reiner. Electrophoresis in Practice : A Guide to Methods and Applications of DNA and Protein Separations. Wiley & Sons, Incorporated, John, 2005.
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Westermeier, Reiner. Electrophoresis in Practice : A Guide to Methods and Applications of DNA and Protein Separations. Wiley & Sons, Incorporated, John, 2016.
Trouver le texte intégralChapitres de livres sur le sujet "Separations of proteins mixture"
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Skidmore, Graham L., et Howard A. Chase. « Multi-Component Adsorption of Proteins to Ion Exchangers ». Dans Separations for Biotechnology 2, 418–27. Dordrecht : Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0783-6_45.
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Hill, C. R. « The Manufacture of Proteins for Human Therapeutic Use ». Dans Separations for Biotechnology 2, 431–43. Dordrecht : Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0783-6_46.
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Birkenmeier, Gerd, Per-Ake Ålbertsson et Gerhard Kopperschläger. « Dye Affinity Partitioning of Serum Proteins ». Dans Separations Using Aqueous Phase Systems, 15–23. Boston, MA : Springer US, 1989. http://dx.doi.org/10.1007/978-1-4684-5667-7_3.
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Franco, T., B. A. Andrews, O. Cascone, C. Hodgson, A. T. Andrews et J. A. Asenjo. « Affinity Separation of Proteins in Aqueous Two-Phase Systems ». Dans Separations for Biotechnology 2, 335–44. Dordrecht : Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0783-6_36.
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Hustedt, Helmut, Karl-Heinz Kroner et Neophytos Papamichael. « Continuous Crosscurrent Extraction of Proteins in Process Scale ». Dans Separations Using Aqueous Phase Systems, 299–307. Boston, MA : Springer US, 1989. http://dx.doi.org/10.1007/978-1-4684-5667-7_49.
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Zaslavsky, Boris Y. « Use of the Aqueous Two-Phase Partition Technique for Characterization and Quality Control of Recombinant Proteins ». Dans Aqueous Biphasic Separations, 177–83. Boston, MA : Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-1953-9_15.
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D’ Addario, Ezio, Michele Patrissi, Maurizio Masi, Giuseppe Storti et Sergio Carra’. « Adsorption-Desorption of Proteins in RP-HPLC RNase on C4 Supports ». Dans Separations for Biotechnology 2, 305–14. Dordrecht : Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0783-6_33.
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Adachi, Motonari. « Affinity-Based Reverse Micellar Separations ». Dans Methods for Affinity-Based Separations of Enzymes and Proteins, 181–94. Basel : Birkhäuser Basel, 2002. http://dx.doi.org/10.1007/978-3-0348-8127-2_10.
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Zydney, Andrew L., et Ralf Kuriyel. « 4 High-Performance Tangential Flow Filtration for Protein Separations ». Dans Downstream Processing of Proteins, 35–46. Totowa, NJ : Humana Press, 2000. http://dx.doi.org/10.1007/978-1-59259-027-8_4.
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McIntosh, Ronald V., et Peter R. Foster. « Process Design for the Inactivation of Viruses in the Manufacture of Pharmaceutical Proteins ». Dans Separations for Biotechnology 2, 499–505. Dordrecht : Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0783-6_53.
Texte intégralActes de conférences sur le sujet "Separations of proteins mixture"
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Hsieh, Yi-Cheng, Huinan Liang et Jeffrey D. Zahn. « Microdevices for Microdialysis and Membrane Separations ». Dans ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-55052.
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Microdialysis is a commonly used technique for separating small biomolecules within a complex biological mixture for continuous biochemical monitoring. Microdialysis is based upon controlling the mass transfer rate of small biomolecules diffusing across a semipermeable membrane into a dialysis fluid while excluding larger molecules such as proteins. These small molecules are subsequently sensed using a biosensor. Since many biosensors are extremely susceptible to fouling, their stability and lifetime can be extended if metabolites are filtered through a microdialysis membrane before the dialysis fluid is moved into the sensor. Dialysis is also used commonly in biological laboratories to desalt high ionic strength protein solutions. As biochemical analysis systems become more integrated for μTAS systems there is a need to automate this process. Thus, an on-chip dialysis system is useful for biochemical reaction engineering where very tight control of ionic conditions must be maintained for effective enzymatic activity. This work demonstrates the ability to integrate polymer microdialysis membranes with microfluidic systems. Microchannels are bonded with a regenerated cellulose membrane. After microchannels are produced using standard processing techniques, they are integrated with these membranes. The cellulose is activated in an oxygen plasma followed by a lamination bond to the microchannels at moderate pressure and elevated temperature. Devices were placed in a solution of rhodamine dye, and dialysis fluid was allowed to flow through the microchannels. The outlet dye concentration was measured by fluorescence intensity as a function of flow rate and follows analytically predicted results.
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Fan, Z. Hugh, Champak Das, Cesar Moreira, Daniel Olivero et Hong Chen. « Microfluidic Devices for Rapid Protein Separation ». Dans 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70208.
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We present our investigation of using microfluidic devices for rapid protein separation. The devices were made from cyclic olefin copolymers that have high optical clarity and high glass transition temperature. Protein separation was achieved by using isoelectric focusing (IEF) and polyacrylamide gel electrophoresis (PAGE). A laser-induced fluorescence (LIF) imaging system was developed to detect proteins while they migrated under an electric field. IEF was carried out in a separation medium consisting of carrier ampholytes and a mixture of linear polymers. Dynamic coating of the linear polymers prevented proteins from adsorption and suppressed electroosmotic flows. PAGE was achieved in twenty-nine parallel channels. In addition, we integrated IEF with PAGE in a microfluidic device for two-dimensional protein separation.
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Myung, Ja Hye, Cari A. Launiere, Khyati A. Gajjar, David T. Eddington et Seungpyo Hong. « Enhanced Tumor Cell Separation by Surfaces Functionalized With Combinations of Bioadhesive Proteins ». Dans ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13210.
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Effective detection of circulating tumor cells (CTCs) can provide important diagnostic and prognostic information of metastatic cancer. However, CTCs are extremely rare and estimated to be only in the range of one tumor cell in the background of 106–109 normal blood cells, hindering clinically significant detection.[1–2] The specific capturing and potential enrichment of CTCs using anti-epithelial cell adhesion molecule (anti-EpCAM)[3] and selectin, respectively, inspire a biofunctionalized surface that mimics biological complexity may detect and isolate target cells at a greater sensitivity and specificity. This concept is supported by the initial physiological interactions between CTCs and endothelium in the bloodstream, which include concurrent rolling and stationary binding steps. Towards this aim, we investigated the following: i) two proteins with distinct biofunctions (selectin to induce rolling and anti-EpCAM to statically capture target cells) can be co-immobilized; ii) a combined rolling and stationary binding can be induced by the mixture of the proteins; and iii) the biomimetic combination enhances overall capture efficiency of the surface. As a proof-of-concept study for the hypothesis of enhanced separation capacity and capture efficiency using protein mixtures, the surfaces are tested using in vitro cell lines (MCF-7 cells as a CTC model and HL-60 cells as a leukocyte model) under flow conditions. The effects of the combination of rolling (E-selectin) and stationary binding (anti-EpCAM) on capture efficiency are compared to a surface functionalized solely with anti-EpCAM.
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Piët, M. P. J., S. Chin, A. M. Prince et B. Horowitz. « INACTIVATION OF VIRUSES IN PLASMA ON TREATMENT WITH TRI(N-BUTYL) PHOSPHATE (TNBP) DETERGENT MIXTURES ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644149.
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Treatment of plasma with organic solvent/ detergent mixtures at the time of plasma collection or plasma pooling could reduce the exposure of technical staff to infectious virus and enhance the viral safety of final product. Treatment of plasma for 4 hours with 2% TNBP at 37°C or with 1% TNBP and 1% Tween 80 or Triton X-45 at 30°C resulted in the rapid and complete inactivation of ≥104 tissueculture infectious doses (TCID-50) ofvesicularstomatitis and Sindbis viruses, used as surrogates. TNBP and TNBP/Tween treatment of plasma was shown to inactivate ≥104 TCID-50 of human immunodeficiency virus. TNBPtreatment of plasma contaminated with 106 chimpanzee infectious doses (CID-50) of HBV and 105 CID-50 of NANBHV prevented the transmission of hepatitisto chimpanzees through 6 months follow-up.Immediately following treatment with 2% TNBP, the recovery of AHF, factor IX, factor V, and antithrombin IIIwas 75%,90%, 65% and 100%,respectively. A ⊕90% recovery of AHF was observed with TNBP/detergent mixtures. Treated plasma was fractionated intoAHF and prothrombin complex concentrates, immune globulin, and albumin by published techniques. Prior treatmentwithTNBP or TNBP and detergent did not affect the separations of desired proteins. Therefore, it appears possible to inactivate viruses in plasma prior to execution of standard fractionation procedures. If desirable, products prepared from TNBP-treated plasmacan be subjected to additional procedures to further insure virus safety.
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MacDonald, Ian, et George Berg. « A Mixture of Experts Method for Predicting Domain Boundaries in Proteins ». Dans 2007 IEEE 7th International Symposium on BioInformatics and BioEngineering. IEEE, 2007. http://dx.doi.org/10.1109/bibe.2007.4375751.
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Davis, Bradley J., Guillaume Michal, Cheng Lu et Valerie Linton. « Separation Characteristics of an X65 Linepipe Steel From Laboratory-Scale to Full-Scale Fracture Tests ». Dans 2020 13th International Pipeline Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipc2020-9545.
Texte intégralRésumé :
Abstract Separations are small fissures that form along the rolling-plane of some steels when sufficient stresses are created to open planes of weakness in the material. In the pipeline industry, separations have been observed on the fracture surfaces of tensile, Charpy, and drop-weight tear tests — the key tests for determining the fracture arrest capabilities of line pipe steels. When compared, the separation appearance between lab-scale tests and full-scale fracture test are noticeably dissimilar. Therefore, the influence separations have on the fracture behaviour may not clearly scale between lab-scale and full-scale tests. In this study, the separation severity of Charpy, DWTT, and full-fracture propagation test fracture surfaces was measured and compared. Two full-scale burst tests were carried out with pipes containing a CO2/N2 mixture. Fracture surfaces were observed along the length of the pipe and captured when the separation appearance changed. For each pipe section, the corresponding lab-scale test surfaces were compared. With the separations measured across all fracture faces, the separation appearance of the full-scale test surfaces did not provide the same values as the lab-scale tests. However, the lab-scale tests did capture the trend in separation severity for each pipe section. Only the lab-scale test surfaces showed a correlation in separation severity.
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Bresee, James C., Patricia D. Paviet et Terry A. Todd. « US Department of Energy’s CoDCon Project : An Aqueous Safeguards R&D Program ». Dans 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-67965.
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In 2015, Office of Nuclear Energy of the U.S. Department of Energy established a research and development project at Pacific Northwest National Laboratory to evaluate the process control capability to produce a specific uranium/plutonium product from used commercial nuclear fuel using an aqueous co-decontamination separations process. The process is controlled using on-line instrumentation supported by a dynamic process model. The new program is called the CoDCon project. The result of the study will be a quantitative measure of the current capability to produce a specific U/Pu product, using U-IV to reduce plutonium to Pu-III and prepare a mixed product, the composition predicted by a dynamic model, measured with on-line instrumentation and controlled by the adjustment of process variables. This approach would be an alternative to the use of the PUREX aqueous separations process that produces separate plutonium and uranium products that are later blended to prepare the desired mixture. Since plutonium is always accompanied by uranium, the project will provide a safeguards-by-design tool for possible use in future commercial separations plant designs. The effectiveness of the design tool will be quantified using a methodology published by B. Cipiti, et al1. The paper describes the process and the control system used by the project and provides details on the current status of the research and development program. Since this advanced process control system may have international applications, arrangements will be described for possible foreign participation in the project.
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Zubair, Muhammad, Aman Ullah et Jianping Wu. « Spent hen proteins : An untapped bioresource for food packaging applications ». Dans 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/wasw9203.
Texte intégralRésumé :
Spent hens, a poultry by-product, have little economic value for processing due to poor meat quality and low yield. In North America alone, 150 million spent hens are produced every year which are either end up in landfill or burnt. However, there are concerns over disposal of spent hens; therefore, it is pertinent to find out alternative uses that are environmentally friendly. On the other hand, single-use plastic packaging is leading to a global environmental crisis. The development of hybrid bionanocomposite films from spent hen proteins using cellulose nanocrystals (CNCs) is a viable option for food packaging applications. In this study, proteins were harvested from spent hen using alkali aided extraction method. To develop protein derived bionanocomposite films, glycerol was used as a plasticizer and chitosan as a cross-linker agent. Furthermore, cellulose nanocrystals (1,3,5%) were incorporated into the proteins/glycerol/chitosan mixture and sonicated it for an hour. Finally, mixture was transformed into food packaging films using compression molding and characterized using FTIR, XRD, TEM, DMA, DSC and TGA.The results indicated that alkali aided method provided excellent proteins recovery yield (74%) and percentage purity (96%) from spent hen. The physicochemical analysis showed an improvement in the thermal, mechanical, and barrier properties of the prepared bionanocomposite films. A greater enhancement in mechanical strength (2.65± 0.50 to 8.48±0.98 MPa) of CNCs derived films was observed as compared to films without nanoparticles. Transmission electron microscopy images confirmed the dispersion of CNCs into the protein polymeric chains which resulted in good exfoliation/intercalation of CNCs and improved the overall properties of the films.The above results suggested that spent hen proteins have great future potential to develop protein/CNCs hybrid bionanocomposite films with improved functional properties for food packaging applications. The petro-based plastic environmental impacts can be reduced with the development of these environmentally benign bionanocomposite films.
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Han, Chungmin, et Jaesung Park. « Size Based Particle Separation Method by Zero Diffusivity ». Dans ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53393.
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Separation is one of the most basic and frequently using techniques for biological research. Researchers have been using gel-electrophoresis for DNA separation and also using various chromatography techniques for protein and bio-molecule separations. Recently, as micro and nano fabrication techniques have developed, interest in miniaturized micro scale biology research tools has also increased. According to this trend, micro scale devices for separating various sized of particles such as cells, organelles, proteins, lipids and vesicles play an important role in a total system. Therefore, separation devices based on various methods are suggested. Widely used separation methods for micro devices are electro-kinetics with special channel geometries and laminar flow control. In electro-kinetic methods, micro channel electrophoresis and DEP (dielectrophoresis) are commonly used.[1] These separation methods, however, can only be used in very narrow range because their working conditions, high voltage and charge dependence, are not compatible with many biomaterials.
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Castro, Alonso, et Brooks Shera. « Electrophoresis of Single Fluorescent Molecules ». Dans Laser Applications to Chemical Analysis. Washington, D.C. : Optica Publishing Group, 1994. http://dx.doi.org/10.1364/laca.1994.thd.3.
Texte intégralRésumé :
The fast, efficient detection and separation of minute quantities of biologically important molecules plays a central role in a variety of fields, such as molecular biology, biotechnology, immunology, medical diagnostics, and forensic analysis. It has proven difficult to identify and separate biomolecules at such low concentrations by existing means. Thus, it is of importance to develop methods that are able to probe such low concentrations with adequate sensitivity, resolution and ease. Here, we describe a new method for detecting and identifying individual fluorescent molecules in solution. The technique involves the measurement of electrophoretic velocities of individual molecules in a mixture, and identification by comparison with the electrophoretic velocity known to be characteristic of a particular molecular species. The application of the method to the detection and size identification of DNA restriction fragments in solution at the single molecule level has been demonstrated. In a similar experiment, the electrophoretic velocities of single molecules of the protein phycoerythrin was determined. Although we have focused on the detection and identification of biologically important molecules, the technique has the potential to find applications in organic and inorganic chemical analysis.
Rapports d'organisations sur le sujet "Separations of proteins mixture"
1
Naim, Michael, Andrew Spielman, Shlomo Nir et Ann Noble. Bitter Taste Transduction : Cellular Pathways, Inhibition and Implications for Human Acceptance of Agricultural Food Products. United States Department of Agriculture, février 2000. http://dx.doi.org/10.32747/2000.7695839.bard.
Texte intégralRésumé :
Historically, the aversive response of humans and other mammals to bitter-taste substances has been useful for survival, since many toxic constituents taste bitter. Today, the range of foods available is more diverse. Many bitter foods are not only safe for consumption but contain bitter constituents that provide nutritional benefits. Despite this, these foods are often eliminated from our current diets because of their unacceptable bitterness. Extensive technology has been developed to remove or mask bitterness in foods, but a lack of understanding of the mechanisms of bitterness perception at the taste receptor level has prevented the development of inhibitors or efficient methods for reducing bitterness. In our original application we proposed to: (a) investigate the time course and effect of selected bitter tastants relevant to agricultural products on the formation of intracellular signal molecules (cAMP, IP3, Ca2+) in intact taste cells, in model cells and in membranes derived therefrom; (b) study the effect of specific bitter taste inhibitors on messenger formation and identify G-proteins that may be involved in tastant-induced bitter sensation; (c) investigate interactions and self-aggregation of bitter tastants within membranes; (d) study human sensory responses over time to these bitter-taste stimuli and inhibitors in order to validate the biochemical data. Quench-flow module (QFM) and fast pipetting system (FPS) allowed us to monitor fast release of the aforementioned signal molecules (cGMP, as a putative initial signal was substituted for Ca2+ ions) - using taste membranes and intact taste cells in a time range below 500 ms (real time of taste sensation) - in response to bitter-taste stimulation. Limonin (citrus) and catechin (wine) were found to reduce cellular cAMP and increase IP3 contents. Naringin (citrus) stimulated an IP3 increase whereas the cheese-derived bitter peptide cyclo(leu-Trp) reduced IP3 but significantly increased cAMP levels. Thus, specific transduction pathways were identified, the results support the notion of multiple transduction pathways for bitter taste and cross-talk between a few of those transduction pathways. Furthermore, amphipathic tastants permeate rapidly (within seconds) into liposomes and taste cells suggesting their availability for direct activation of signal transduction components by means of receptor-independent mechanisms within the time course of taste sensation. The activation of pigment movement and transduction pathways in frog melanophores by these tastants supports such mechanisms. Some bitter tastants, due to their amphipathic properties, permeated (or interacted with) into a bitter tastant inhibitor (specific phospholipid mixture) which apparently forms micelles. Thus, a mechanism via which this bitter taste inhibitor acts is proposed. Human sensory evaluation experiments humans performed according to their 6-n-propyl thiouracil (PROP) status (non-tasters, tasters, super-tasters), indicated differential perception of bitterness threshold and intensity of these bitter compounds by different individuals independent of PROP status. This suggests that natural products containing bitter compounds (e.g., naringin and limonin in citrus), are perceived very differently, and are in line with multiple transduction pathways suggested in the biochemical experiments. This project provides the first comprehensive effort to explore the molecular basis of bitter taste at the taste-cell level induced by economically important and agriculturally relevant food products. The findings, proposing a mechanism for bitter-taste inhibition by a bitter taste inhibitor (made up of food components) pave the way for the development of new, and perhaps more potent bitter-taste inhibitors which may eventually become economically relevant.