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  • 1
    ISSN: 0173-0835
    Keywords: Band dispersion ; Polyacrylamide gel ; Uncrosslinked polyacrylamide solutions ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The dispersion coefficient, D′, of the representative homogeneous protein, conalbumin, decreases linearly as the polyacrylamide concentration increases from 4 to 14%T (2%C), and varies in a biphasic fashion as %C (Bis) is increased from 2 to 20%, with a broad peak between 5 and 15%C. D′ increases linearly with the concentration of the initiator, potassium persulfate, in the range of 0.01-0.15%. D′ remains constant when the field strength is varied from 5 to 15 V/cm. A DNA fragment (1857 bp) exhibits a constant D′ in 4-6% polyacrylamide (2%C) at a field strength of 1 V/cm, and a linearly increasing D′ at 5 V/cm, in analogy to its previously observed behavior in agarose gels. In solutions of uncrosslinked polyacrylamide, the decrease of the D′ of conalbumin with polymer concentration is not significantly different from that in 2% N,N′-methylenebisacrylamide-crosslinked gels in the range of 4-14%T, while the decrease of mobility with polyacrylamide concentration is much steeper in 2% crosslinked compared to uncrosslinked polymer. Finally, -∂ (log D′)/∂T was found to be proportional to the retardation coefficient, KR (= -∂ (log μ)/∂T), in polyacrylamide gels. The ratio of -∂ (log D′)/∂T over KR increases with field strength in the range of 5-15 V/cm.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 17 (1996), S. 80-83 
    ISSN: 0173-0835
    Keywords: Automated gel electrophoresis apparatus ; Resolution ; Gel thickness ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Gel electrophoresis in commercial automated apparatus (HPGE-1000, LabIntelligence, Menlo Park, CA) is conventially conducted in gels of 3 mm thickness at about 15 V/cm. Since the intermittent scanning of the gel allows one to measure band width as a function of migration time, resolution may be evaluated quantitatively. Comparing the value of resolution between two proteins in electrophoresis on agarose gels of 0.5 and 3.0 mm thickness and at various field strengths, it was found that within the given Joule heat dissipation capacity of the apparatus, resolution between the proteins is improved when the gel thickness is reduced from 3.0 to 0.5 mm, which allows for an increase in field strength from 15 V/cm, conventional for that apparatus, to 45 V/cm.
    Additional Material: 3 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 16 (1995), S. 2069-2073 
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Dynamic control ; Reproducibility ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Dynamic control in capillary electrophoresis (CE) is able to provide better resolution, shorter separation time, reduced band broadening and better reproducibility for the separations of organic and inorganic ions and large molecules such as proteins and DNA. This article provides an overview of dynamic control in CE by several techniques: pH, temperature, external electric field, and field amplification. These techniques take advantage of the changes in electroosmotic flow coefficient, electrophoretic mobilities of the analytes due to changes in equilibrium, viscosity of the buffer solution, and/or electric field strength. The basic theories and applications to the improvement of the separation performance for standard samples in CE by using these dynamic control techniques are presented. Finally, the advantages and shortcomings of these techniques and the future trends of dynamic control for the separations of real samples are discussed.
    Additional Material: 2 Ill.
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  • 4
    ISSN: 0173-0835
    Keywords: Band area ; Protein ; Automated electrophoresis ; Automated apparatus ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: An automated gel electrophoresis apparatus, recently available commercially, allows one to follow the band during electrophoresis in real time, and lends itself therefore to an evaluation of bandwidth as a function of migration time (the dispersion coefficient), resolution and band shape. These determinations assume the constancy of band area with migration time and at various gel concentrations. The purpose of the present study was to verify these assumptions. Representative proteins and sodium dodecyl sulfate (SDS)-proteins, either natively fluorescent or fluorescein carboxylate labeled, were found to exhibit band areas which approach constancy as a function of migration time in both agarose and polyacrylamide gel electrophoresis, provided that (i) the protein concentration under the band was low enough to obviate self-quenching of fluorescence; (ii) the separation of the protein of interest from contaminants had progressed sufficiently during the time at which band areas were measured; (iii) the baseline under the peak was sufficiently well defined. However, band areas decrease with increasing gel concentration. Protein peaks exhibited leading and trailing tails. The ratio of the combined tail area to total area appeared to be near-constant at varying migration times. However, that ratio increases with increasing gel concentration. The tail area does not appear to be an artifact of fluorometric detection since it is reproduced upon fluorimetric analysis of the protein eluted from gel slices after electrophoresis. However, it may be due to photochemical destruction under the conditions of repetitive fluorometric peak detection.
    Additional Material: 6 Ill.
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  • 5
    ISSN: 0173-0835
    Keywords: Poly(ethylene oxide) solution ; kbp-sized dsDNA ; Capillary electrophoresis ; Electroosmotic flow ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: DNA fragments of 1 to 10 kbp in length were separated by capillary electrophoresis (CE), using poly(ethylene oxide) (PEO) solutions in the presence of electroosmotic flow. The technique requires filling the capillary with the polymer solution by means of electroosmotic flow (EOF). Separation times of 6-7 min in PEO solutions ranging from 0.3 to 8 × 106 Mr at 375 V/cm were sufficient to separate the 11 components of the dsDNA ladder (0.5 to 10 kbp) by size. The migration behavior of the double-stranded (ds)DNA fragments, interpreted by “Ferguson plot analysis”, in the system is indistinguishable from that previously reported for capillary zone electrophoresis (CZE) in a polyacrylamide solution without EOF. Potential advantages of conducting CZE using polymer solutions in the presence of EOF are: (i) Possibility of long migration times on short columns; (ii) possibility of introducing relatively viscous, high Mr polymer solutions into narrow capillaries; (iii) possibility of establishing polymer concentration gradients in capillaries; (iv) possibility of concentrating the starting zone by balancing electrophoretic migration and electroosmotic transport.
    Additional Material: 5 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 16 (1995), S. 952-957 
    ISSN: 0173-0835
    Keywords: Electrophoresis ; Stacking ; Sample volume capacity ; Automated apparatus ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Horizontal gel electrophoresis has previously suffered from lack of an instrumental design that would allow for application of large sample volumes. A recently introduced commercial apparatus (HPGE-1000, LabIntelligence) remedies that problem in application to gel electrophoresis with intermittent scanning of fluorescence by using the concentrator module of that apparatus as a stacking gel reservoir. By using this technique and a 3 mL stacking gel, protein samples of up to 1.5 mL yield bands in the horizontal resolving gel that are independent of sample volume in their width, area and migration rate. A remaining procedural problem relates to the apparent nonsimultaneity of dye and protein entrance into the resolving gel, which necessitates peak characterization by absolute rather than relative mobilities.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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