Nuclear transplantation with melanophores, ciliated epidermal cells, and the established cell-line A-8 in Xenopus laevis

Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 539-547
Author(s):  
H. R. Kobel ◽  
R. B. Brun ◽  
M. Fischberg
Keyword(s):  
Cell Line ◽  
Cultured Cells ◽  
Important Change ◽  
Epidermal Cells ◽  
Nuclear Transplantation ◽  
Established Cell Line ◽  
Donor Nucleus ◽  
Established Cell ◽  
Developmental Programme ◽  
Set Up

The developmental potencies of melanophores, ciliated epidermal cells and cells from an established line were tested by means of nuclear transplantation into enucleated Xenopus eggs. Donor nuclei from ciliated epidermal cells of hatching tadpoles never gave rise, after transplantation, to development beyond the blastula stage; nuclei from non-ciliated cells of the same larvae, on the other hand, could fully replace a zygote nucleus. Melanophore nuclei taken from the tailfin of advanced larvae (stage 56) gave rise to blastulae and, in one case, an incipient invagination was observed. Melanophore nuclei taken from tissue cultures, set up from hatching tadpoles, proved to be competent for leading development as far as the heartbeat stage, (stage 33/34), the embryo showing well-elaborated eye Anlagen, muscles, notochord, cement gland, etc. Nuclei from the highly aneuploid established cell-line A-8 were able to give rise to hatching-stage embryos. These results suggest that some condition, provided by culturing, influences the differentiated state so as to improve the chances of the donor nucleus co-operating with the egg's developmental programme. The important change might be the state of proliferation attained in cultured cells.

Studies on the use of cultured cells in a bioassay for parathyroid hormone

1994 ◽  
Vol 143 (2) ◽  
pp. 261-268
Author(s):  
A E Armston ◽  
P J Wood
Keyword(s):  
Parathyroid Hormone ◽  
Cyclic Amp ◽  
Cell Line ◽  
Cultured Cells ◽  
Biologically Active ◽  
Kidney Cell Line ◽  
Opossum Kidney ◽  
Pre Treatment ◽  
Set Up ◽  
Insufficient Sensitivity

Abstract Measurement of parathyroid hormone (PTH) is important for diagnosing hyper- and hypoparathyroidism. The move to two-site immunometric assays that detect the whole molecule has improved the discrimination of these conditions but these assays may be too restrictive because some PTH fragments that are biologically active may not be detected. In addition, PTH-like peptide of malignancy, an important cause of malignancy-associated hypercalcaemia, is not detected by the two-site assays. Experiments were performed to set up a simple, robust and inexpensive bioassay for PTH, exploiting a kidney cell line and using cyclic AMP or an eluted stain assay as the end point. Of the 12 cell lines tested, an opossum kidney (WOK) cell line showed the most promise. Despite optimization of the procedure to include pre-treatment with dexamethasone, insulin and PTH, followed by incubation in the presence of 5′ -guanylimidodiphosphate, isobutyl-1-methylxanthine and forskolin, the WOK cells showed insufficient sensitivity for use in a cultured cell bioassay for PTH in human serum. In addition, the cells were less sensitive to PTH-like peptide precluding their use for an assay for this molecule. Journal of Endocrinology (1994) 143, 261–268

Enhancement of pheomelanogenesis by L-dopa in the mouse melanocyte cell line, TM10, in vitro

1987 ◽  
Vol 87 (4) ◽  
pp. 507-512
Author(s):  
C. Sato ◽  
S. Ito ◽  
T. Takeuchi
Keyword(s):  
Cell Line ◽  
Growth Medium ◽  
Yellow Pigment ◽  
Black Pigment ◽  
Established Cell Line ◽  
Treatment Results ◽  
Common Precursor ◽  
Established Cell ◽  
The Common

Cells of TM10, an established cell line, are melanocytes that contain equal amounts of eumelanin (black pigment) and pheomelanin (yellow pigment). The content of pheomelanin drastically increased when the cells were cultured in growth medium containing 0.2mM-L-dopa (L-dihydroxyphenylalanine), which is the common precursor for both eumelanogenesis and pheomelanogenesis. After this treatment, the amount of pheomelanin was 3.7-fold greater than that of control in TM10, whereas the amount of eumelanin changed very little. In contrast, 5-S-cysteinyl-dopa, which is the specific precursor for pheomelanogenesis downstream of L-dopa, did not cause preferential increase in pheomelanogenesis. Ultrastructural observations also confirmed these results; in 0.2mM-L-dopa, an increase in the number of pheomelanosomes was observed in the cytoplasm of TM10 cells. Our results also suggest that the L-dopa treatment results in a decrease in tyrosinase activity per melanosome.

Sodium channels in membrane vesicles from cultured toad bladder cells

1988 ◽  
Vol 254 (4) ◽  
pp. C512-C518 ◽  
Author(s):  
C. Asher ◽  
A. Moran ◽  
B. C. Rossier ◽  
H. Garty
Keyword(s):  
Hormonal Regulation ◽  
Cultured Cells ◽  
Electrical Potential ◽  
Membrane Vesicles ◽  
Tracer Uptake ◽  
Established Cell Line ◽  
Na Channel ◽  
Porous Support ◽  
Established Cell ◽  
Bladder Cells

Electrical potential-driven 22Na+ fluxes were measured in membrane vesicles prepared from TBM-18(c123) cells (a clone of the established cell line TB-M). Fifty to seventy percent of the tracer uptake in vesicles derived from cells that were cultivated on a porous support were blocked by the diuretic amiloride. The amiloride inhibition constant was less than 0.1 microM, indicating that this flux is mediated by the apical Na+-specific channels. Vesicles prepared from cells that were not grown on a porous support exhibited much smaller amiloride-sensitive fluxes. Two Ca2+-dependent processes that down-regulate the channel conductance and were previously identified in native epithelia were found in the cultured cells as well. Vesicles isolated from cells that were preincubated with 5 X 10(-7) M aldosterone for 16-20 h exhibited higher amiloride-sensitive conductance than vesicles derived from control, steroid-depleted cells. Thus membrane derived from TBM-18(c123) cells can be used to characterize the epithelial Na+ channel and its hormonal regulation.

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