Abstract

The karyotypes of Biomphalaria alexandrina and Bulinus truncatus were analyzed comparatively and classified on the basis of centromere position and the electrophoretic analysis of tissue protein has been used to determine the relationships between the ova of Schistosoma mansoni and Schistosoma haematobium and their respective snail hosts. The two species have the same diploid chromosome number, 2n = 36. The mitotic chromosomes of B. alexandrina are organized in three groups and consist of 8 metacentric pairs, 8 submetacentric pairs and 2 subtelocentric pairs of chromosomes. While, the karyotype of B. truncatus is organized in four groups and consists of 10 metacentric pairs, 4 submetacentric pairs, 2 telocentric pairs, and 2 subtelocentric pairs of chromosomes. Also, SDS-PAGE revealed 7 similar protein bands in the ova of S. mansoni and its snail host B. alexandrina and 5 similar protein bands in S. haematobium and its snail host B. truncatus. Additionally, the highest similarity coefficient was found between B. alexandrina and B. truncatus and their respective trematode hosts. It is hoped in the near future to identify targets in the snail host that interfere with parasite survival and develop alternate and/or novel methods to disrupt the transmission of schistosomiasis.

Key words: Biomphalaria alexandrina, Bulinus truncatus, Schistosoma mansoni, Schistosoma haematobium, chromosomes, electrophoretic analysis.