AJP - Cell Physiology, Vol 249, Issue 1 32-C40, Copyright © 1985 by American Physiological Society
Primary culture of duck salt gland. I. Morphology of confluent cell layers
R. J. Lowy, J. H. Schreiber, D. C. Dawson and S. A. Ernst
Dissociated avian salt gland secretory cells were maintained in primary
culture after plating on hydrated collagen gels. When seeded at 3 X 10(6)
cells/cm2, confluent cell sheets formed within 2-3 days, whereas cultures
seeded at lower densities formed a complex reticulum of cell aggregates,
which remained nonconfluent even after 7 days. Scanning electron microscopy
showed that the free surface of 3-day confluent cultures consisted of
intermixed convex and flattened cell membranes with prominent junctional
boundaries and abundant microvilli. Transmission electron microscopy
indicated that these cultures were multilayers of 1-4 cells in thickness.
The plasma membranes of the superficial cells were polarized into apical
and basolateral regions displaying, respectively, microvilli and
interdigitating lateral membrane folds. These membrane domains were
separated by shallow occluding junctions, which consisted of both single
strands and simple net-like arrays in freeze-fracture images. Underlying
epithelial cells retained lateral membrane folds and formed desmosomal
contacts with superficial and neighboring cells. These cultures, unlike the
intact tissue, allow direct access to the apical and basolateral cell
surfaces for electrophysiological analysis of transmural active ion
transport.
