The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Yordan Kostov - One of the best experts on this subject based on the ideXlab platform.
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Distinguishing between whole Cells and Cell Debris using surface plasmon coupled emission.
Biomedical optics express, 2018Co-Authors: Muhammad Anisuzzaman Talukder, Curtis R. Menyuk, Yordan KostovAbstract:Distinguishing between whole Cells and Cell Debris is important in microscopy, e.g., in screening of pulmonary patients for infectious tuberculosis. We propose and theoretically demonstrate that whole Cells and Cell Debris can be distinguished from the far-field pattern of surface plasmon coupled emission (SPCE) of a fluorescently-labeled sample placed on a thin metal layer. If fluorescently-labeled whole Cells are placed on the metal film, SPCE takes place simultaneously at two or more different angles and creates two or more distinct rings in the far field. By contrast, if fluorescently-labeled Cell Debris are placed on the metal film, SPCE takes place at only one angle and creates one ring in the far-field. We find that the angular separation of the far-field rings is sufficiently distinct to use the presence of one or more rings to distinguish between whole Cells and Cell Debris. The proposed technique has the potential for detection without the use of a microscope.
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Distinguishing between whole Cells and Cell Debris using surface plasmon coupled emission (Conference Presentation)
Imaging Manipulation and Analysis of Biomolecules Cells and Tissues XV, 2017Co-Authors: Muhammad Anisuzzaman Talukder, Curtis R. Menyuk, Yordan KostovAbstract:Distinguishing between intact Cells, dead but still whole Cells, and Cell Debris is an important but difficult task in life sciences. The most common way to identify dead Cells is using a Cell-impermeant DNA binding dye, such as propidium iodide. A healthy living Cell has an intact Cell membrane and will act as a barrier to the dye so that it cannot enter the Cell. A dead Cell has a compromised Cell membrane, and it will allow the dye into the Cell to bind to the DNA and become fluorescent. The dead Cells therefore will be positive and the live Cells will be negative. The dead Cells later deteriorate quickly into Debris. Different pieces of Debris from a single Cell can be incorrectly identified as separate dead Cells. Although a flow cytometer can quickly perform numerous quantitative, sensitive measurements on each individual Cell to determine the viability of Cells within a large, heterogeneous population, it is bulky, expensive, and only large hospitals and laboratories can afford them. In this work, we show that the distance-dependent coupling of fluorophore light to surface plasmon coupled emission (SPCE) from fluorescently-labeled Cells can be used to distinguish whole Cells from Cell Debris. Once the fluorescent labels are excited by a laser, the fluorescently-labeled whole Cells create two distinct intensity rings in the far-field, in contrast to fluorescently-labeled Cell Debris, which only creates one ring. The distinct far-field patterns can be captured by camera and used to distinguish between whole Cells and Cell Debris.
R. H. Cumming - One of the best experts on this subject based on the ideXlab platform.
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Flocculation of Cell Debris from ultrasonicated Escherichia coli.
Biotechnology and bioengineering, 1991Co-Authors: Elaine Gellan, G. F. Martin, R. H. CummingAbstract:Cell Debris of Escherichia coli produced by ultrasonication was flocculated with acid. The Debris settled at pH 3 and 4, but not at pH 2. Extensive protein precipitate formed in lysates at low pH. The results were compared with whole Cells flocculated by acid.
Muhammad Anisuzzaman Talukder - One of the best experts on this subject based on the ideXlab platform.
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Distinguishing between whole Cells and Cell Debris using surface plasmon coupled emission.
Biomedical optics express, 2018Co-Authors: Muhammad Anisuzzaman Talukder, Curtis R. Menyuk, Yordan KostovAbstract:Distinguishing between whole Cells and Cell Debris is important in microscopy, e.g., in screening of pulmonary patients for infectious tuberculosis. We propose and theoretically demonstrate that whole Cells and Cell Debris can be distinguished from the far-field pattern of surface plasmon coupled emission (SPCE) of a fluorescently-labeled sample placed on a thin metal layer. If fluorescently-labeled whole Cells are placed on the metal film, SPCE takes place simultaneously at two or more different angles and creates two or more distinct rings in the far field. By contrast, if fluorescently-labeled Cell Debris are placed on the metal film, SPCE takes place at only one angle and creates one ring in the far-field. We find that the angular separation of the far-field rings is sufficiently distinct to use the presence of one or more rings to distinguish between whole Cells and Cell Debris. The proposed technique has the potential for detection without the use of a microscope.
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Distinguishing between whole Cells and Cell Debris using surface plasmon coupled emission (Conference Presentation)
Imaging Manipulation and Analysis of Biomolecules Cells and Tissues XV, 2017Co-Authors: Muhammad Anisuzzaman Talukder, Curtis R. Menyuk, Yordan KostovAbstract:Distinguishing between intact Cells, dead but still whole Cells, and Cell Debris is an important but difficult task in life sciences. The most common way to identify dead Cells is using a Cell-impermeant DNA binding dye, such as propidium iodide. A healthy living Cell has an intact Cell membrane and will act as a barrier to the dye so that it cannot enter the Cell. A dead Cell has a compromised Cell membrane, and it will allow the dye into the Cell to bind to the DNA and become fluorescent. The dead Cells therefore will be positive and the live Cells will be negative. The dead Cells later deteriorate quickly into Debris. Different pieces of Debris from a single Cell can be incorrectly identified as separate dead Cells. Although a flow cytometer can quickly perform numerous quantitative, sensitive measurements on each individual Cell to determine the viability of Cells within a large, heterogeneous population, it is bulky, expensive, and only large hospitals and laboratories can afford them. In this work, we show that the distance-dependent coupling of fluorophore light to surface plasmon coupled emission (SPCE) from fluorescently-labeled Cells can be used to distinguish whole Cells from Cell Debris. Once the fluorescent labels are excited by a laser, the fluorescently-labeled whole Cells create two distinct intensity rings in the far-field, in contrast to fluorescently-labeled Cell Debris, which only creates one ring. The distinct far-field patterns can be captured by camera and used to distinguish between whole Cells and Cell Debris.
Peter Dunnill - One of the best experts on this subject based on the ideXlab platform.
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The use of laboratory centrifugation studies to predict performance of industrial machines: Studies of shear-insensitive and shear-sensitive materials
Biotechnology and Bioengineering, 2000Co-Authors: J. P. Maybury, Mike Hoare, Peter DunnillAbstract:A method for using a bench-top centrifuge is described in order to mimic the recovery performance of an industrial-scale centrifuge, in this case a continuous-flow disc stack separator. Recovery performance was determined for polyvinyl acetate particles and for biological process streams of yeast Cell Debris and protein precipitates. Recovery of polyvinyl acetate particles was found to be well predicted for these robust particles. The laboratory centrifugation scale-down technique again predicted the performance of the disc stack centrifuge for the recovery of yeast Cell Debris particles although there was some suggestion of over-prediction at high levels of Debris recovery due to the nature of any Cell Debris aggregates present. The laboratory centrifuge scale-down technique also proved to be an important investigative probe into the extent of shear-induced breakup of shear-sensitive protein precipitate aggregates during recovery in continuous high speed centrifuges. Such breakup can lead to over 10-fold reduction in separator capacity.
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Monitoring recombinant inclusion body recovery in an industrial disc stack centrifuge
Biotechnology and Bioengineering, 1994Co-Authors: K. Jin, Owen R.t. Thomas, Peter DunnillAbstract:A simple and rapid spectrophotometric method for measuring recombinant inclusion body concentrations in the presence of Escherichia coli Cell Debris has been applied to monitoring the performance of an industrial disc stack centrifuge. Turbidimetric measurements were made at two wavelengths, i.e., 600 nm and 420 nm, and the ratios of OD600nm/OD420nm related to the particle composition in suspension. The principle behind the technique is that inclusion body particles scatter light at 600 nm more effectively than do smaller Cell Debris particles when compared with the degree of light scatter at 420 nm. This technique may have broad potential application in developing an automatic monitoring and control system for industrial-scale inclusion body recovery. © 1994 John Wiley & Sons, Inc.
Luuk A.m. Van Der Wielen - One of the best experts on this subject based on the ideXlab platform.
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selective recovery of polyhydroxyalkanoate inclusion bodies from fermentation broth by dissolved air flotation
Journal of Colloid and Interface Science, 2006Co-Authors: Pim Van Hee, Rob G. J. M. Van Der Lans, Andrea C M R Elumbaring, Luuk A.m. Van Der WielenAbstract:Selective dissolved-air flotation for the separation of medium-chain-length polyhydroxyalkanoate (PHA) inclusion bodies (IBs) from Pseudomonas putida Cell Debris is investigated. Measurements show that both P. putida Cell Debris and PHA IBs have an iso-electric point of approximately pH 3.5. Selective aggregation and as a result selective flotation of PHA IBs was observed near this pH. Qualitative prediction of the aggregation behaviour was possible on the basis of the Van der Waals, hydrophobic and electrostatic interactions. In some cases however, the stability of the suspension could not be explained with these forces alone. It was therefore suggested that additional interactions, such as steric/brush effects, play an important role in the aggregation process.
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Relation between Cell disruption conditions, Cell Debris particle size, and inclusion body release.
Biotechnology and Bioengineering, 2004Co-Authors: Pim Van Hee, Anton P. J. Middelberg, Rob G. J. M. Van Der Lans, Luuk A.m. Van Der WielenAbstract:The efficiency of physical separation of inclusion bodies from Cell Debris is related to Cell Debris size and inclusion body release and both factors should be taken into account when designing a process. In this work, Cell disruption by enzymatic treatment with lysozyme and Cellulase, by homogenization, and by homogenization with ammonia pretreatment is discussed. These disruption methods are compared on the basis of inclusion body release, operating costs, and Cell Debris particle size. The latter was measured with cumulative sedimentation analysis in combination with membrane-associated protein quantification by SDS-PAGE and a spectrophotometric peptidoglycan quantification method. Comparison of the results obtained with these two Cell Debris quantification methods shows that enzymatic treatment yields Cell Debris particles with varying chemical composition, while this is not the case with the other disruption methods that were investigated. Furthermore, the experiments show that ammonia pretreatment with homogenization increases inclusion body release compared to homogenization without pretreatment and that this pretreatment may be used to control the Cell Debris size to some extent. The enzymatic disruption process gives a higher product release than homogenization with or without ammonia pretreatment at lower operating costs, but it also yields a much smaller Cell Debris size than the other disruption process. This is unfavorable for centrifugal inclusion body purification in this case, where Cell Debris is the component going to the sediment and the inclusion body is the floating component. Nevertheless, calculations show that centrifugal separation of inclusion bodies from the enzymatically treated Cells gives a high inclusion body yield and purity.
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Quantification of solid Cell material by detection of membrane-associated proteins and peptidoglycan.
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2004Co-Authors: Pim Van Hee, Anton P. J. Middelberg, Rob G. J. M. Van Der Lans, Luuk A.m. Van Der WielenAbstract:Quantification of solid Cell material (Cell Debris) is necessary for the optimisation of the efficiency of bioseparations. Cell Debris can be quantified by detection of a component present in the Cell wall that can act as a marker for Cell Debris. Membrane-associated proteins have previously been used as a marker for Cell Debris. This marker was quantified by SDS-PAGE with densiometry. In this paper Cell Debris quantification methods are presented that are faster and more accurate, i.e. membrane-associated protein quantification with the Protein 50 Labchip(R) of Agilent Technologies, or that make use of peptidoglycan as marker for Cell Debris, i.e. a spectrophotometric muramic acid assay. (C) 2004 Elsevier B.V. All rights reserved.