2003 Volume 36 Issue 2 Pages 141-146
Previous studies on cell contraction in the ciliate Spirostomum have suggested that action may not be present, in spite of its ubiquity in other ciliates including Paramecium and Tetrahymena. In this study, different anti-actin antibodies were used to re-examine whether actin occurs in Spirostomum. Western blotting analysis with these anti-actin antibodies showed that actin-like proteins may exist in Spirostomum. Intracellular localization of actin-like proteins was examined by immunofluorescene microscopy with the same antibodies. Fluorescent signals were seen at the cleavage furrow, around the macronucleus, and at the ciliary bases including those of the membranelle. These results suggest that actin may exist in Spirostomum, but it is different from skeletal muscle actin and Tetrahymena actin in antigenic characteristics.
