Investigations of cytoskeletal elements in cultured bovine meshwork cells

An ultrastructural, immunohistochemical, and functional study was conducted on cultured bovine meshwork cells. Particular emphasis was placed on the organization of the cytoskeleton, and the cells were viewed either as whole cells or following detergent extraction. For ultrastructural examination, several modes of viewing were adopted, including a detector situated above the specimens collecting secondary electrons (SE), a detector situated beneath the specimen collecting transmitted electrons (STEM), and conventional transmission electron microscopy at 100 KV (TEM). In whole cell mounts, information was obtained about the organization of the cytoskeleton and its relationship to other cytoplasmic organelles. Extraction procedures removed much of the plasma membrane and most organelles. The nucleus and cytoskeleton remained and stress fibers were prominent. Immunohistochemistry showed that the actin content of the cytoskeleton could be preserved after detergent extraction. Detergent-extracted cells decreased their surface area when exposed to MgATP in a dose-dependent manner. The decrease in surface area was associated with disassembly of cytoskeletal stress fibers and was optimal with 1 mM MgATP. Whether or not the change in surface area could be considered a "contractile event" was discussed.