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  • Artikel  (4)
  • CHO cells  (4)
  • Springer  (4)
  • American Meteorological Society
  • Blackwell Publishing Ltd
  • International Union of Crystallography
  • Springer Nature
  • Wiley
  • 2020-2022
  • 2000-2004  (4)
  • 1975-1979
  • Werkstoffwissenschaften, Fertigungsverfahren, Fertigung  (4)
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  • Artikel  (4)
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  • Springer  (4)
  • American Meteorological Society
  • Blackwell Publishing Ltd
  • International Union of Crystallography
  • Springer Nature
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  • 1
    ISSN: 1573-0778
    Schlagwort(e): CHO cells ; erythropoietin ; glycosylation ; glutamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The molecular heterogeneity of recombinant humanerythropoietin (EPO) increased during the course of abatch culture of transfected Chinese hamster ovary(CHO) cells grown in serum-free medium. This wasshown by both an increased molecular weight and pIrange of the isolated EPO at the end of the culture. However, analysis of the N-glycan structures of themolecule by fluorophore-assisted carbohydrateelectrophoresis (FACE) and HPLC anion exchangechromatography indicated a consistent pattern ofglycosylation. Seven glycoforms were identified, thepredominant structure being a fully sialylatedtetra-antennary glycan. The degree of sialylationwas maintained throughout the culture. Analysis ofthe secreted EPO indicated a time-dependent increasein the molecular weight band width of the peptideconsistent with proteolytic degradation. A highglutamine concentration (16–20 mM) in the culturedecreased the apparent degradation of the EPO.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1573-0778
    Schlagwort(e): CHO cells ; culture condition ; modelparticles ; operation cut off ; perfusion cultivation ; retention ; spinfilter ; tip speed
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Since 1969 much attention has been devoted to the useof spinfilter systems for retention of mammalian cellsin continuous perfusion cultivations. Previousinvestigations dealt with hydrodynamic conditions,fouling processes and upscaling. But hydrodynamicconditions and fouling processes seem to have asecondary importance in spinfilter performance duringauthentic perfusion cultivations. Obviously,alterations in culture condition are more relevantespecially during long-term processes. Therefore, ourpratical approach focussed on the performance qualityof a commercially available 20 μm spinfilterduring a perfusion cultivation of a recombinant CHOcell line in pilot scale regarding the followingissues: 1) retention of viable cells in thebioreactor; 2) removal of dead cells and cell debrisfrom the bioreactor; 3) alterations in culturecondition; and 4) changes in perfusion mode.Furthermore, we tested the performance of 20 μmspinfilters in 2 and 100 l pilot scale using solidmodel particles instead of cells. Our investigationsshowed that retention of viable cells in pilot scalewas independent of spinfilter rotation velocity andperfusion rate; the retention increased from 75 to 95%corresponding to operation time, enlarging celldiameter and enhanced formation of aggregates in theculture during the perfusion cultivation. By means ofthe Cell Counter and Analyzer System (CASY) anoperation cut off of 13 μm was determined forthis spinfilter. Using solid model particles in 2 lscale, optimal retention was achieved at a tip speedof 0.43 m s-1 (141 rpm) – furtherenhancement of spinfilter rotation velocity up to0.56 m s-1 (185 rpm) decreased the retentionrapidly. In pilot scale best retention performance wasobtained with tip speeds of 0.37 m s-1(35 rpm) and 1.26 m s-1 (120 rpm). Hence,significant retention in pilot scale could already beachieved with low agitation. Therefore, the additionof shear force protectives could be avoided so thatthe purification of the target protein from thesupernatant would be facilitated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1573-0778
    Schlagwort(e): CHO cells ; gel microdrops ; human antibody ; population parameters ; productivity ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The long-term stability of high-level expression is the mostimportant factor to consider when choosing cell lines for the expression of recombinant proteins. Declining volumetricyields in large-scale fermentation can be caused by changes affecting the cell population as a whole such as loss in viability, depletion of nutrients or accumulation of metabolites affecting cell growth. Alternatively, geneticinstability may lead to the outgrowth of a less productive,metabolically favored sub-population. Currently a variety ofparameters are measured to monitor the condition of cells infermenters including glucose uptake, lactate accumulation andoxygen consumption; in addition, periodic viable cell countsallow the determination of the growth rate and viability of the population. All of these methods measure the condition ofthe cell population as a whole and changes must involve a significantly large proportion of the total culture in orderto be detectable. Here we report on a method that allows theevaluation of the productivity of individual cells. Using the gel microdrop secretion assay, we detected the appearance ofa sub-population of cells with lower productivity. Subsequentanalysis of the culture confirmed the existence of lower productivity cells with a lower vector copy number. Therefore,the single cell secretion assay proved to be a rapid method todetect and isolate a low productivity variant of the producer cell line.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1573-0778
    Schlagwort(e): adherent CHO cells ; CHO cells ; morphology of CHO cells ; osmolarity ; suspended CHO cells ; tissue plasminogen activator
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The effects of constant osmolarity, between 300 and500 mOsm/kg, on the metabolism of Chinese HamsterOvary (CHO) cells producing tissue plasminogenactivator (tPA) were compared between adhesion andsuspension cultures. In both suspension and adhesionculture, the specific rates of glucose consumption(νG), lactate production (qL), and tPAproduction (qtPA) increased as osmolarityincreased, while these rates decreased when osmolaritywas higher than the respective critical levels. However, specific growth rate (μ) decreased withincrease in osmolarity and this slope grew steeper inthe osmolarity range higher than the critical level. The decrease in μ in the adhesion culture was morerapid than that in the suspension culture. Thecritical osmolarity for adhesion culture (400 mOsm/kg)was lower than that for suspension culture (450 mOsm/kg). These results indicated that the adhesionculture was more sensitive to increase of osmolaritythan the suspension culture, while the specific ratesobtained from the adhesion cultures were in general1.5- to 3-fold higher than those obtained from thesuspension cultures. Cell volume increased asosmolarity increased in both the suspension andadhesion cultures, as reported previously forsuspension culture of hybridoma cells, but there wasno morphological change in the suspension culture. Incontrast, cell height decreased and cell adhesion areamarkedly increased as osmolarity increased in theadhesion culture. This morphological change inadhesion cultures may be one reason for the highersensitivity of adherent cells to the increase ofosmolarity than suspended cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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