scholarly journals DISTINCTIVE CHARACTERISTICS OF NUCLEOLI OF TWO ESTABLISHED CELL LINES

1971 ◽  
Vol 49 (3) ◽  
pp. 803-815 ◽  
Author(s):  
David M. Phillips ◽  
Stephanie G. Phillips
Keyword(s):  
Cell Lines ◽  
Cultured Cells ◽  
Chinese Hamster ◽  
Mouse Cell ◽  
Particulate Material ◽  
Gradual Disappearance ◽  
Established Cell ◽  
Nucleolar Volume ◽  
Light Area ◽  
Nucleolar Components

Nucleoli of cultured cells of the established lines KB and L were found to possess a distinctive fine structural organization. The major portion of the nucleolar volume was composed of compact, particulate material. Spheroidal fibrillar zones about 0.4 µ in diameter occurred within the particulate mass. These fibrillar zones had a central light area and a denser rim. Toyocamycin treatment, which sharply inhibited the appearance of newly synthesized RNA in the cytoplasm, caused the gradual disappearance of the fibrillar material from nucleoli. Actinomycin D treatment, which inhibited virtually all RNA synthesis, caused varying types of segregation of nucleolar components. The morphology of nucleoli of KB and L cells and the reorganization of these nucleoli in response to drugs appear to be different from those of nucleoli of freshly initiated Chinese hamster and mouse cell lines.

scholarly journals Demonstration of Isoantigenic Receptors on Human Epidermal Cells and Established Cell Lines

Blood ◽  
1965 ◽  
Vol 25 (1) ◽  
pp. 96-104 ◽  
Author(s):  
EDMOND J. YUNIS ◽  
JORGE J. YUNIS ◽  
K. GERHARD BRAND
Keyword(s):  
Cell Lines ◽  
Human Cell ◽  
Cultured Cells ◽  
Mouse Cell ◽  
Epidermal Cells ◽  
Established Cell Lines ◽  
Human Cell Cultures ◽  
Human Epidermal Cells ◽  
Established Cell ◽  
Cell Strains

Abstract This paper describes mixed agglutination and serum absorption experiments for the demonstration of A, B, H, M, N, D, C, E, c and e isoantigens in human epidermal cells and cultured cells. It was found that only A, B and H antigens are present on human epidermal cells and that this does not appear to be related to the secretor status of the donor. The same antigens were also examined on six different established human cell strains (HeLa, EE, ERK-1, Maben, Chang conjunctiva, Chang liver), and one established mouse cell strain (L). It was found that the H antigen persists in established human cell cultures. The M antigen which is not seen in normal epithelial cells can be demonstrated on HeLa cells by mixed agglutination reaction and by absorption experiments. Guinea pig antisera against established cell lines of human origin were found to contain a small fraction of agglutinins with H specificity, but no anti-M, anti-N or anti-Rh agglutinins.

scholarly journals NUCLEOLI OF DIPLOID CELL STRAINS

1971 ◽  
Vol 49 (3) ◽  
pp. 785-802 ◽  
Author(s):  
Stephanie G. Phillips ◽  
David M. Phillips
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Chinese Hamster ◽  
Diploid Cell ◽  
Particulate Material ◽  
Gradual Disappearance ◽  
Mouse Cells ◽  
Cell Strains ◽  
Nucleolar Components

Nucleoli of cultured Chinese hamster or mouse cells in early passages had a loosely reticular substructure. Within the reticulum small, irregularly shaped, light fibrillar zones occurred which were contiguous with denser fibrillar zones. These denser zones appeared to be connected in some places to the particulate material which composed the mass of the nucleolus. Generally, electron-transparent spaces separated the particulate zones from the fibrillar areas. Treatment with toyocamycin, an agent which is reported to cause a blockage in the processing of ribosomal RNA, greatly inhibited the accumulation of newly synthesized RNA in the cytoplasm, as monitored by radioautography. Toyocamycin treatment caused the gradual disappearance of the granules from the particulate region of the nucleoli, and resulted ultimately in the nucleoli appearing homogeneously fibrillar. Actinomycin D treatment, which inhibited virtually all RNA synthesis, caused a segregation, and finally a disaggregation, of nucleolar components.

scholarly journals Studies of fibronectin matrices in living cells with fluoresceinated gelatin.

1980 ◽  
Vol 87 (1) ◽  
pp. 14-22 ◽  
Author(s):  
P Hsieh ◽  
R Segal ◽  
L B Chen
Keyword(s):  
Extracellular Matrix ◽  
Chick Embryo ◽  
Cell Surface ◽  
Cell Lines ◽  
Cultured Cells ◽  
Living Cells ◽  
Low Concentration ◽  
Established Cell Lines ◽  
The Matrix ◽  
Established Cell

We have used fluorescein isosthiocyanate-conjugated gelatin (FITC-gelatin) (1 mg/ml) to localize cell surface fibronectin in unfixed live cells in cultures. FITC-gelatin stains the fibronectin matrix on primary cultures of rat and chick embryo fibroblasts as well as untransformed, established cell lines. In live cultured cells, fibronectin in many areas of the extracellular matrix is inaccessible to antibody and cannot be visualized by immunofluorescence staining. In contrast, fibronectin in these areas is fully stainable by FITC-gelatin. At a low concentration (20 micrograms/ml), FITC-gelatin stains the fibronectin matrix of primary cultured cells but not of "untransformed" established cell lines. SEM can detect only the matrix stainable with the low concentration of FITC-gelatin, such as that expressed by primary chick embryo fibroblasts. The binding of fibronectin to the extracellular matrix is very stable and FITC-gelatin remained bound to the matrix for at least 10 d in culture. Radioiodinated gelatin has been used to quantitate the level of cell surface fibronectin in living normal and transformed cells. FITC-gelatin appears to be a useful probe for studying the fibronectin of living cells in culture.

In vitro growth-stimulatory property of pigeon milk

1993 ◽  
Vol 71 (5-6) ◽  
pp. 303-307 ◽  
Author(s):  
L. Bharathi ◽  
K. B. Shenoy ◽  
M. Mojamdar ◽  
S. N. Hegde
Keyword(s):  
Cell Lines ◽  
Cho Cells ◽  
Cultured Cells ◽  
Guanidine Hydrochloride ◽  
Chinese Hamster ◽  
Growth Stimulation ◽  
Relative Mass ◽  
Good Growth ◽  
In Vitro Growth

Five cell lines were employed to test the growth-stimulating property of pigeon milk in vitro. All the cell lines except A431 showed good growth response to crude homogenates of pigeon milk. Enhancement of DNA synthesis in quiescent Chinese hamster ovary (CHO) cells by pigeon milk was dose dependent up to a concentration of 1%. In vitro growth stimulation by 1% pigeon milk was approximately equal to that by 2% foetal bovine serum (FBS) when CHO cells were used, growth stimulation of Vero cells by 1% pigeon milk was roughly three times of that by 2% FBS. In contrast, 1% pigeon milk was only half as active as 2% FBS on NIH/3T3 cells and five times less active than 2% FBS on human foetal lung fibroblast cells. After dialysis using a relative mass (Mr) cutoff of 3500, the pigeon milk mitogenic activity was retained in the dialyzed solution, although it decreased by 40–60% when dialyzed with Mr cutoffs of 8000 and 12 000 – 14 000. The growth-stimulating activity of pigeon milk was resistant to heat, acid, alkali, and the action of urea, guanidine hydrochloride, dithiothreitol, and trypsin. We suggest that pigeon milk is a new source of growth factor(s) capable of stimulating in vitro the growth of many mammalian cell types.Key words: pigeon milk, growth stimulation, cultured cells.

scholarly journals Effects of Physicochemical Properties of Polyacrylamide (PAA) and Polydimethylsiloxane (PDMS) on Cardiac Cell behavior

Soft Matter ◽  
2021 ◽  
Author(s):  
Karim Daliri ◽  
Kurt Pfannkuche ◽  
Bora Garipcan
Keyword(s):  
Cell Lines ◽  
Cultured Cells ◽  
Cell Behavior ◽  
Cardiac Cell ◽  
Established Cell Lines ◽  
The World ◽  
Established Cell ◽  
Primary Origin ◽  
Transformed Cell Lines

In vitro cell culture is commonly applied in laboratories around the world. Cultured cells are either of primary origin or established cell lines. Such transformed cell lines are increasingly replaced...

scholarly journals Differential activation of the hprt gene on the inactive X chromosome in primary and transformed Chinese hamster cells.

1989 ◽  
Vol 9 (4) ◽  
pp. 1635-1641 ◽  
Author(s):  
S G Grant ◽  
R G Worton
Keyword(s):  
Cell Lines ◽  
X Chromosome ◽  
Gene Activation ◽  
Chinese Hamster ◽  
Fibroblast Cell ◽  
Dna Demethylation ◽  
Hprt Gene ◽  
Primary Fibroblast ◽  
Chinese Hamster Cells ◽  
Inactive X Chromosome

We have investigated the genetic activation of the hprt (hypoxanthine-guanine phosphoribosyltransferase) gene located on the inactive X chromosome in primary and transformed female diploid Chinese hamster cells after treatment with the DNA methylation inhibitor 5-azacytidine (5azaCR). Mutants deficient in HPRT were first selected by growth in 6-thioguanine from two primary fibroblast cell lines and from transformed lines derived from them. These HPRT- mutants were then treated with 5azaCR and plated in HAT (hypoxanthine-methotrexate-thymidine) medium to select for cells that had reexpressed the hprt gene on the inactive X chromosome. Contrary to previous results with primary human cells, 5azaCR was effective in activating the hprt gene in primary Chinese hamster fibroblasts at a low but reproducible frequency of 2 x 10(-6) to 7 x 10(-6). In comparison, the frequency in independently derived transformed lines varied from 1 x 10(-5) to 5 x 10(-3), consistently higher than in the nontransformed cells. This increase remained significant when the difference in growth rates between the primary and transformed lines was taken into account. Treatment with 5azaCR was also found to induce transformation in the primary cell lines but at a low frequency of 4 x 10(-7) to 8 x 10(-7), inconsistent with a two-step model of transformation followed by gene activation to explain the derepression of hprt in primary cells. Thus, these results indicate that upon transformation, the hprt gene on the inactive Chinese hamster X chromosome is rendered more susceptible to action by 5azaCR, consistent with a generalized DNA demethylation associated with the transformation event or with an increase in the instability of an underlying primary mechanism of X inactivation.

scholarly journals Affecting HEK293 Cell Growth and Production Performance by Modifying the Expression of Specific Genes

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1667
Author(s):  
Laura Abaandou ◽  
David Quan ◽  
Joseph Shiloach
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Hek293 Cell ◽  
Chinese Hamster ◽  
Production Performance ◽  
Cellular Processes ◽  
Hek293 Cell Line ◽  
Global Engineering ◽  
Genomic Tools ◽  
Serum Free Suspension

The HEK293 cell line has earned its place as a producer of biotherapeutics. In addition to its ease of growth in serum-free suspension culture and its amenability to transfection, this cell line’s most important attribute is its human origin, which makes it suitable to produce biologics intended for human use. At the present time, the growth and production properties of the HEK293 cell line are inferior to those of non-human cell lines, such as the Chinese hamster ovary (CHO) and the murine myeloma NSO cell lines. However, the modification of genes involved in cellular processes, such as cell proliferation, apoptosis, metabolism, glycosylation, secretion, and protein folding, in addition to bioprocess, media, and vector optimization, have greatly improved the performance of this cell line. This review provides a comprehensive summary of important achievements in HEK293 cell line engineering and on the global engineering approaches and functional genomic tools that have been employed to identify relevant genes for targeted engineering.

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