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A Daphnia Parasite ( Caullerya mesnili ) Constitutes a New Member of the Ichthyosporea, a Group of Protists near the Animal–Fungi Divergence
Author(s) -
LOHR JENNIFER N.,
LAFORSCH CHRISTIAN,
KOERNER HENRIKE,
WOLINSKA JUSTYNA
Publication year - 2010
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2010.00479.x
Subject(s) - biology , internal transcribed spacer , parasite hosting , zoology , host (biology) , daphnia , protozoa , spore , divergence (linguistics) , evolutionary biology , ecology , crustacean , genetics , ribosomal rna , microbiology and biotechnology , gene , linguistics , philosophy , world wide web , computer science
.Caullerya mesnili is a protozoan endoparasite in the gut epithelium of Daphnia , which causes regular epidemics in lakes throughout Europe. Its classification has remained unchanged for over a century, leaving it placed with the Haplosporidia, despite speculation that this position is incorrect. The difficulty in classifying C. mesnili stems from its few known morphological and ecological characteristics, as well as a lack of genetic markers. Here we sequenced the nuclear small subunit (SSU) and internal transcribed spacer rDNA regions of C. mesnili samples from 10 locations. Based on sequence similarities, we suggest the re‐classification of C. mesnili to the Ichthyosporea, a class of protists near the animal–fungi divergence. We report average intragenomic variation of 0.75% and 2.27% in the SSU and internal transcribed spacer regions, respectively. From electron micrographs and light microscopy of histological sections we determined that C. mesnili spores grow within the intestinal epithelium where they establish themselves intercellularly. In addition, we confirmed previous accounts regarding the high virulence of this parasite. Caullerya mesnili reduces host lifespan, the number of clutches, and the total number of offspring. This high selection pressure placed on hosts supports the importance of C. mesnili as a model parasite for the study of host–parasite biology in permanent lakes.