scholarly journals Calcium-binding protein of chorioallantoic membrane: identification and development expression.

1977 ◽  
Vol 74 (5) ◽  
pp. 1946-1949 ◽  
Author(s):  
R. S. Tuan ◽  
W. A. Scott
Keyword(s):  
Calcium Binding ◽  
Binding Protein ◽  
Chorioallantoic Membrane ◽  
Calcium Binding Protein

scholarly journals Calcium-binding protein of the chick chorioallantoic membrane. I. Immunohistochemical localization

1978 ◽  
Vol 77 (3) ◽  
pp. 743-751 ◽  
Author(s):  
RS Tuan ◽  
WA Scott ◽  
ZA Cohn
Keyword(s):  
Calcium Binding ◽  
Calcium Transport ◽  
External Surface ◽  
Binding Protein ◽  
Chorioallantoic Membrane ◽  
Immunohistochemical Localization ◽  
Calcium Binding Protein ◽  
Transport Function ◽  
Chick Chorioallantoic Membrane

The preparation of a specific antiserum (anti-CaBP) against the calcium-binding protein (CaBP) of the chorioallantoic membrane (CAM) is described. The anti-CaBP appeared to be specific for the CaBP by immunodiffusion and immunoelectrophoresis. Application of the anti-CaBP in immunofluorescence histochemistry revealed that the CaBP is present in the CAM only at developmental ages corresponding with the expression of the calcium transport function of the membrane. Furthermore, the CaBP is localized to the ectoderm of the CAM, appears to be exposed to the entire external surface of the ectoderm, and can be shown to be associated with cells enzymatically dissociated from the CAM. These results are consistent with a functional role of the CaBP in the CAM calcium transport process.

Calcium-transport function of the chick embryonic chorioallantoic membrane. II. Functional involvement of calcium-binding protein, Ca2+-ATPase and carbonic anhydrase

1986 ◽  
Vol 82 (1) ◽  
pp. 85-97
Author(s):  
R.S. Tuan ◽  
M.J. Carson ◽  
J.A. Jozefiak ◽  
K.A. Knowles ◽  
B.A. Shotwell
Keyword(s):  
Carbonic Anhydrase ◽  
Calcium Binding ◽  
Calcium Transport ◽  
Calcium Uptake ◽  
Binding Protein ◽  
Chorioallantoic Membrane ◽  
Calcium Binding Protein ◽  
Transport Pathway ◽  
Functional Involvement ◽  
Active Calcium

This study aimed to investigate the mechanism of active calcium transport in the chick embryonic chorioallantoic membrane (CAM) by assessing the functional involvement of three previously identified, putative components of the transport pathway. These components are a calcium-binding protein (CaBP), Ca2+-activated ATPase and carbonic anhydrase. Using specific reagents, including antibodies and enzyme inhibitors in vivo and in vitro in CAM calcium uptake assays, it was shown that these biochemically identified components were all functionally involved. The results of these studies also indicate that active calcium uptake by the CAM requires the presence of the CaBP on the cell surface in a laterally mobile manner, while carbonic anhydrase appeared to be a cytosolic component. We further analysed the subcellular location of the calcium-uptake activity by gel filtration and density-gradient fractionation of cell-free microsomes of the CAM and the results suggest that this activity is associated with the plasma membrane.

scholarly journals Calcium-binding protein of the chick chorioallantoic membrane. II. Vitamin K-dependent expression

1978 ◽  
Vol 77 (3) ◽  
pp. 752-761 ◽  
Author(s):  
RS Tuan ◽  
WA Scott ◽  
ZA Cohn
Keyword(s):  
Vitamin D ◽  
Vitamin K ◽  
Calcium Binding ◽  
Binding Protein ◽  
Vitamin K Antagonists ◽  
Chorioallantoic Membrane ◽  
Calcium Binding Protein ◽  
Simple Method ◽  
Chick Chorioallantoic Membrane

A simple method was devised for the maintenance of the chorioallantoic membrane (CAM) of chick embryos in organ culture. Explants of CAM survived for up to 5 days in this system and retained the characteristic three-layered morphology (ectoderm, mesoderm, and endoderm). Induction of the CAM calcium-binding protein (CaBP) by effectors of calcium metabolism was studied in these organ cultures. Vitamin K was found to elicit a seven- to eightfold increase in CaBP, whereas no increase in CaBP activity occurred on supplementation with vitamin A, parathyroid hormone, an analogue of vitamin D, vitamin D and its hydroxylated metabolites, or with elevated calcium levels. The vitamin K-mediated induction of CaBP was dose-dependent, inhibited by the vitamin K antagonists warfarin and dicoumarol, selective for vitamin K5, and maximal at the developmental stage (13-15 days of incubation) corresponding to the onset of calcium transport by the CAM in vivo. CaBP levels increased after 60-70 h in cultures of 13-15 day CAM supplemented with vitamin K and reached maximal levels around 80-90 h of culture. The CAM ectoderm underwent extensive proliferation and often assumed a villuslike morphology in the vitamin K cultures.

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