Actin filaments in the ruminal epithelium of cattle

Phalloidin and immunogold labeling were used to localize actin filaments in the ruminal pilar epithelium of adult cattle on the light and electron microscopic level. Incubation with rhodaminyl-phalloidin permitted an overview of general actin distribution pattern. Distinct subcellular localization of actin was revealed with the biotin-streptavidin bridge technique in a postembedding procedure. Superior fixation of membranes and filaments was achieved with tannic acid-glutaraldehyde. Surface-etching prior to immunoincubation ensured restoration of actin immunoreactivity. Patterns of distribution in non-keratinized and keratinized epithelial cells as well as in pericytes and endothelial cells point to cell-specific cytoskeletal and motile functions of actin filaments.