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31.
A new disposable cell culture unit for adherent cell lines, the CellCube, was used to grow a variety of mammalian cell lines. A small unit with 2m2 growth surface area generated up to 4·109 cells. The disposable system consists of a series of polystyrene plates, mounted into a cubical container. A simple construction consisting of a spinner system for medium conditioning, rotameters for gas mixing and a peristaltic pump for medium circulation provided conditions for culture growth.Abbreviations COS M6
Green Monkey Kidney Cells
- SKNMC
Human Neuroblastoma Cell Line
- BHK
Baby Hamster Kidney Cells
- CHO
Chinese Hamster Ovary Cells
- EDTA
Ethtylenediaminetetraacetic Acid
- PBS
Phosphate Buffered Saline
- FCS
Fetal Calf Serum
- MEM
Minimum Essential Medium, Alpha Modification 相似文献
32.
Red blood cells from neonatal calves, but not from adult cows, rapidly hemolyze in buffered 300 mM solutions of a variety of nonelectrolytes and amino acids. Of these compounds, sucrose is chosen to elucidate the mechanism by which this preferential hemolysis takes place. As in other mammalian red cells, both calf and cow cells are found to be impermeable to sucrose and, in an isosmolar sucrose solution, to undergo volume shrinkage caused by the net loss of chloride ions with concomitant increase in intracellular pH. To test the potential role of intracellular pH change associated with chloride loss in promoting hemolysis, intracellular pH was altered by: (a) a direct addition of fixed acid or base to sucrose solution; (b) the removal of dissolved CO(2) from sucrose solution; and (c) the addition of cells to isotonic NaHCO(3) solution in the absence of sucrose. In all cases, only calf and not cow cells underwent hemolysis. Moreover, 4-acetamido-4’-isothiocyano-2,2’-stilbene disulfonic acid, a potent anion transport inhibitor, completely protected calf cells from hemolysis and caused a nearly total inhibition of both chloride loss and intracellular alkalinization. Furthermore, the hemolytic process is closely related to the integrity of a membrane protein, the band 3 protein, which can be cleaved to varying degrees by the combined treatment of pronase and lipase. Hemolysis is progressively inhibited as the band 3 protein undergoes proteolysis, until a total inhibition of hemolysis takes place when almost all of the band 3 protein is digested into smaller protein components with a mol wt of 65,000 and 35,000 daltons. These results suggest that the intracellular alkalinization process leading to a structural instability of the membrane band 3 protein is responsible for this calf cell hemolysis. 相似文献
33.
Pig Reticulocytes. III. Glucose permeability in naturally occurring reticulocytes and red cells from newborn piglets 总被引:1,自引:1,他引:0
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The loss of facilitated glucose transport of red cells occurring in the newborn pig was monitored in 11 density-separated cells from birth to a 4 wk of age. At birth there was a threefold increase in glucose permeability from the lightest cells to the most dense, suggesting that cells having progressively less glucose permeability are released into the circulation as gestation proceeds. Because of extraordinary stimulation of erythropoietic activity, the uppermost top fraction constituting 2-3 percent of the total cells is composed purely of reticulocytes in the growing animal. The glucose permeability of these reticulocytes which at birth has a slow but significant rate of 3.7 μmol/ml cell x min at 25 degrees C is rapidly decreased within 3-4 days to the level of reticulocytes produced in the adult in response to phenylhydrazine assault. Moreover, reticulocytes themselves discard their membrane permeability to glucose in the course of maturation to red cells. Thus, even though reticulocytes at birth are permeable to glucose, they will become red cells practically impervious to glucose within a few days. These findings suggest that the transition from a glucose- permeable fetal state to a glucose-impermeable postnatal state is brought about by two mechanisms: (a) dilution of fetal cells by glucose-impervious cells produced coincidentally with or shortly after birth; and (b) elimination of fetal cells, which have a shorter half-life, from the circulation. 相似文献
34.
Large scale transient 5-HT3 receptor production with the Semliki Forest Virus Expression System 总被引:1,自引:0,他引:1
H. D. Blasey B. Brethon R. Hovius H. Vogel H A. P. Tairi K. Lundström L. Rey A. R. Bernard 《Cytotechnology》2000,32(3):199-208
The expression of recombinant proteins with the Semliki Forest Virus (SFV) system has been scaled up to bioreactor scale. As a model protein for this study the human 5-HT3 receptor was chosen. The gene for the receptor was subcloned into the SFV expression plasmid pSFV1. Virus production by in vivo packaging and production of the recombinant protein was scaled up, the latter to a reactor volume of 11.5 l. A VibromixTM agitation system was chosen to overcome aggregation problems of BHK cells in suspension. In the process, cells were first grown to a density of 106 cells/ml, the medium was then exchanged with fresh medium and the culture was infected with the recombinant virus at an estimated multiplicity of infection of 30. 24 h post infection we measured an expression level of 3 million functional 5-HT3 receptors per cell. For harvesting, the cells were pelleted by centrifugation. The receptor protein was purified in a single step (Hovius et al., 1998) by exploiting the hexa-His tag at minimal protein loss (51% yield). Experiments to optimise expression resulted in yields up to 8 million receptors per cell, when the pH of a suspension culture was controlled at pH 7.3. Rapid virus generation and protein production, high protein yields as well as successful large scale application have made the SFV expression system attractive to produce large quantities of recombinant protein in a very short time. After optimisation of the expression conditions (in particular by setting the pH at 7.3), yields were increased twofold. 相似文献
35.
Accessing genetic diversity for crop improvement 总被引:1,自引:0,他引:1
36.
Tanja Sigl Gregor Schlamberger Hermine Kienberger Steffi Wiedemann Heinrich HD Meyer Martin Kaske 《Acta veterinaria Scandinavica》2010,52(1):32
Background
Conjugated linoleic acid (CLA) is a collective term for isomers of octadecadienoic acid with conjugated double-bond system. Thus, it was the objective to investigate whether milk composition and metabolic key parameters are affected by adding CLA to the diet of dairy cows in the first four weeks of lactation. 相似文献37.
Better discrimination was possible between phenylthiocarbamide (PTC)
solutions and the pure solvent when the solvent was a tasteless low-
concentration NaCl solution to which the subject had adapted than when the
solvent was purified water. The reverse was true for 6-n- propylthiouracil
(PROP). The differences in discrimination for PROP and PTC in the different
solvents were caused by differences in the intensity and persistence of
aftertastes, rather than a more intense perception of the PTC and PROP
tastes per se. This has consequences for traditional approaches to
measuring taste sensitivity, as well as indicating that PTC and PROP are
not necessarily equivalent indicators of 'taster' versus 'non-taster'
status.
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