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  • Biochemistry and Biotechnology  (3)
  • Molecular Cell Biology  (2)
  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 10 (1991), S. 22-32 
    ISSN: 0887-3585
    Schlagwort(e): distance geometry ; DISHAN ; DISGEO ; protein structure ; NMR ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: When calculating three-dimensional structures from NMR data, alternative solutions with very large RMS deviation can be obtained. Sometimes local or global inversions of the protein folding can be observed. We call these different solutions topological mirror images, as they keep the correct amino acid chirality. They are observed when the number of restraints is insufficient and represent different solutions from the same scalar information. Therefore they are common in small peptides where the NMR data are often limited and the secondary structure is not very well defined. They can also be observed in large molecules in regions of higher flexibility. In our experience the observation of topological mirror images is independent of the efficiency of sampling of the algorithm used. We present four examples of proteins with different size and folding. We also discuss ways to distinguish among the different solutions.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 930-943 
    ISSN: 0006-3592
    Schlagwort(e): Eschscholtzia californica ; embryogenesis ; somatic embryos ; bioreactor ; macronutrients ; kinetics ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Embryogenic cultures of a transformed Eschscholtzia californica cell line were carried out in a 11-L helical ribbon impeller bioreactor operated under various conditions to evaluate the performance of this equipment for somatic embryo (SE) production. All bioreactor cultures produced SE suspensions with maximum concentrations at least comparable to those obtained from flask control cultures (∼8-13 SE · mL-;1). However, an increase of the mixingspeed, from 60 to 100 rpm, and low sparging rate (∼0.05 VVM, kL a ∼ 6.1 h-;1) for dissolved oxygen concentration (DO) control yielded poorer quality embryogenic cultures. The negative effects on SE production were attributed mainly to the low but excessive shear experienced by the embryogenic cells and/or embryoforming aggregates. High DO (∼60% of air saturation) conditions favored undifferentrated biomass production and high nutrient uptake rates at the expense of the slower SE differentiation process in both flask and bioreactor cultures. Too low DO (-5-10%) inhibited biomass and SE production. The best production of SE (∼44 SE · mL-1 or ∼757 SE · g dw-1 · d-1) was achieved by operating the bioreactor at 60 rpm while controlling DO at ∼20%by surface oxygenation only (0.05 VVM, kL a ∼ 1.4 h-;1). This production was found to be a biomass production/growth-associated process and was mainly limited by the availability of extracellular phosphate, magnesium, nitrogen salts, and carbohydrates. © 1994 John Wiley & Sons, Inc.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 40 (1992), S. 971-977 
    ISSN: 0006-3592
    Schlagwort(e): adsorption ; benzophenanthridine alkaloid ; sanguinarine ; plant cells ; suspension culture ; elicitation ; Papaver somniferum ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The suitability of adsorbent polymeric resins, Amberlite XAD-4 and XAD-7 (Rohm and Hass, Inc.), was investigated for the accumulation of sanguinarine from Papaver somniferum cell cultures. The adsorption and desorption of sanguinarine from aqueous solution was most effective with XAD-7. In addition to sanguinarine, the resins were found to absorb growth regulators and vitamins from the culture medium. Growth inhibition was overcome by delaying for ∼4 days resin addition after cell inoculation in fresh medium. Resin addition (5% wt/vol) to actively growing uneclicited cultures led to increases in sanguinarine production and release of 30% to 40% and 60%, respectively. The addition of resins to elicited cultures led to increases in alkaloid production of up to 50% to 85% with similar increases in alkaloid release as observed for nonelicited cells. Overall yield of sanguinarine increased from 21 mg · g biomass dry weight-1 (dw) for elicited cultures to more than 39 mg · gdw-1 when elicitation was combined with resin addition. Higher quantities of resin (10% to 20% wt/vol) increased marginally the release of sanguinarine into the medium, and on the resin, up to 85% of total production. The use of resin appears promesing for the development of a bioprocess for sanguinarine production by cultured plant cells. © 1992 John Wiley & Sons, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 2 (1974), S. 629-645 
    ISSN: 0091-7419
    Schlagwort(e): Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Concanavalin A (Con A) binding and Con A-mediated hemadsorption to LM cells were found to decrease significantly at both 5-7°C and 15-19°C. The higher of these critical temperatures responds to a change in state of the membrane lipids and can be increased or decreased in cells where the membrane phospholipids contain less or more double bonds, respectively. The lower critical temperature for Con A binding or Con A-mediated hemadsorption does not respond to these changes in membrane lipid composition. Though the amount of Con A bound to the cell surface is a determinant of Con A-mediated agglutinability, the major components of the decreases in Con A-mediated hemadsorption which occur at both these critical temperatures do not have their origin in the decreases in Con A binding which occur over these same temperature ranges - that is 5-7°C and 15-19°C.Con A-mediated hemadsorption measured at 22°C was dramatically inhibited when LM cells were first incubated at 7°C or less. Reversal of this inhibition required 20-30 min of subsequent incubation at 22°C, indicating that factors other than membrane lipid “fluidity” are determinants of agglutinability. LM cells treated with the microtubule-disrupting alkaloids colchicine, colcemid, or vinblastine at concentrations as low as 10-6 M were as much as fourfold more agglutinable with Con A. By contrast, lumicolchicine, an inactive derivative of colchicine, had a slight inhibitory effect on Con A-mediated hemadsorption. Colchicine, vinblastine, or lumicolchicine treatment of LM cells did not alter the quantitative binding of labeled lectin. The results suggest that membrane lipid “fluidity” and the cell cytoskeleton (microtubule/microfilament system) are important determinants of lectin interactions with cell surfaces. The results are interpreted in terms of a model of cell-cell and cell-lectin interactions which assigns a central role to the Con A receptor.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 9 (1978), S. 147-156 
    ISSN: 0091-7419
    Schlagwort(e): variant cell lines ; receptors ; cell surface properties ; concanavalin A ; colchicine ; tumorigenicity ; growth ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: We report the use of three classes of variants from the long-established malignantly transformed LM cell line to demonstrate that the apparent mobility of cell surface receptors need not be dependent on the expression of the transformed phenotype in vitro.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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