A Comparative Study of Willaertia magna (Free-Living Amoeba) from Different Geographic Areas Using Whole-cell and Small-subunit rDNA Restriction Fragment Length Polymorphisms

Abstract

Nine strains of the free-living amoeba Willaertia magna and one of Naegleria fowlen were compared by detection of whole-cell and small subunit ribosomal DNA (ssurDNA) restriction fragment length polymorphisms (RFLPs). Ail strains of W. magna showed identical Pst I whole-cell RFLPs, although variation in Bg1 II, Hae III and Kpn I RFLPs were found. These RFLPs did not correlate with the geographic origin of the strains. Phylogenetic analysis of the whole-cell RFLPs separated the W. magna strains into three distinct clusters. However, these were not sufficiently diverse to indicate interspecies variation. Homologous ssurDNA RFLPs were found for ail strains of W. magna regardless of the restriction endonuclease used. Both the whole-cell and ssurDNA RFLPs were different for W. magna and N. fowleri and can be used to identify the species. On the basis of homologous whole-cell Pst I and ssurDNA RFLPS, the findings of this study confirm that W. magna is a single species genus.