ACTIN EXPRESSION IN SOME PLATYHELMINTHE SPECIES

Actin expression in some Platyhelminthe species was demonstrated by we stern-blotting and immunocytochemical analysis using two distinct anti -actin antibodies: the anti-total actin that reacts against all actin isoforms of higher vertebrates and the anti-alpha SM-1 that recognizes the alpha-smooth muscle (alpha SM) isotype of endothermic vertebrates (Skalli et al., 1986). Western-blotting experiments showed that all s pecies tested, including some free-living Platyhelminthes (Tricladida and Rhabdocoela) and the parasitic Fasciola hepatica, were stained by anti-total actin antibody while only Dugesidae and Dendrocoelidae show ed a positive immunoreactivity against anti-alpha SM-1. These results were confirmed by cytochemical immunolocalization using both avidin bi otin conjugated peroxidase reaction on paraffin sections, and immunogo ld staining on Lowicryl 4KM embedded specimens. Our findings may contr ibute to the understanding of Platyhelminthes phylogeny.