IMMUNOLOGICAL COMPARISONS OF MAJOR CORTICAL CYTOSKELETAL PROTEINS IN 4 ENTODINIOMORPHID CILIATES

Biochemical and immunological studies of the membrane cytoskeleton wer e carried out using the entodiniomorphid ciliated protozoa: Entodinium bursa, Eudiplodinium magii, Epidinium caudatum and Polyplastron multi vesiculatum. Immunological cross-reactions within the four ciliates sh ow significant labelling of proteins with the same or different molecu lar weights among species. Antigenic homologies among cytoskeletal pro teins with variable MW suggest that Ophryoscolecidae have maintained b oth a similar architectural organization and a cytoskeletal function w hile diversifying the MW of many cytoskeletal proteins. A comparative study of the antigenic relationships points away from an evolutionary lineage from simplest (the ancestral Entodinium) to more complex (the intermediate Eudiplodinium and the more advanced Epidinium and then Po lyplastron), and also the linear evolution based on the increasing com plexity of the cytoalimentary system. It suggests a bushy evolution by radiation from unknown ancestral forms. This is supported by sequenci ng of the different entodiniomorphid ribosomal RNAs.