DAO 46:115-121 (2001)  -  doi:10.3354/dao046115

Identity of Naegleria strains isolated from organs of freshwater fishes

I. Dyková1,2,*, I. Kyselová1,2, H. Pecková1, M. Oborník1,2, J. Lukes1,2

1Institute of Parasitology, Academy of Sciences of the Czech Republic, and
2Faculty of Biological Sciences, University of South Bohemia, Branisovská 31,
370 05 Ceské Budejovice, Czech Republic

ABSTRACT: Eighteen Naegleria strains were isolated from organs of freshwater fishes belonging to 5 species. Morphometric study allowed the separation of the Naegleria strains from the non-vahlkampfiid amoeboflagellates, but was inadequate for species determination. Six strains, representatives of groups that had a slightly different cyst size, were selected and corresponding derived clones were subjected to sequence analysis and riboprinting restriction fragment length polymorphism (RFLP)-PCR analysis of the small subunit (SSU) rRNA genes. One strain isolated from the brain of a fish with systemic infection was characterised by an intronless 2 kb long SSU rRNA gene and was identified as N. australiensis. Another 5 strains had a 1.3 kb long group I intron in their SSU rRNA gene and, based on the SSU rRNA sequences and riboprints, RFLP-PCR patterns appeared in phylogenetic trees to be closely related to Naegleria clarki.

KEY WORDS: Naegleria spp. · Fish strains · Molecular taxonomy · SSU rRNA

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