| Popis: |
Bovine mammary epithelial cells (BMEC) were isolated as “organoids” from a mammary gland of a Holstein cow by collagenase/pronase dissociation and low speed centrifugation. When BMEC were cultured on porous membrane or porous plastic sheet coated with extracellular matrixes such as “Matrigel”, they assembled together and showed dramatic morphological changes, i.e. construction of nodule-like, alveolar and tubular structures. When BMEC were cultured in the presence of 35S-Met, several radio-labeled proteins corresponding to bovine milk proteins were detected in the BMEC culture supernatant. Synthesis and secretion of the protein corresponding to αsl-casein were remarkably increased by prolactin, hydrocortisone and insulin. Furthermore, αsl-, β-and κ-caseins were immunologically detected in the culture supernatant by immuno-blotting analysis. As a preliminary experiment for gene manipulation of BMEC, a model gene containing LacZ was introduced into BMEC by the calcium phosphate precipitation method. β-Galactosidase activity was detected in some cells by activity-staining with X-gal, though transfection efficiency was not very high. |
