Evidence for intermediate-like filaments in a heterotrichous ciliate

Abstract

In the heterotrichous ciliate Nyctotherus ovalis, a meshwork of 10 nm filaments present in the cell cortex surrounds cytostome and cytoproct and is connected by thin strands to a perinuclear coat. Like intermediate filaments (If) of higher organisms the filaments are insoluble in non-ionic detergent, and paracrystals can be formed after dissolution in 8 M urea. The cross-reactions of these filaments with monoclonal anti-vimentin and anti-cytokeratin antibodies suggest that they share common epitopes with both types of If proteins.