title: Multiple species of the dinophagous dinoflagellate genus Amoebophrya infect the same host species.
abstract: Populations of the dinoflagellate Dinophysis norvegica in the Baltic Sea and in the adjacent North Sea are infected by the endoparasite Amoebophrya sp. The high diversity recently unveiled within the genus Amoebophrya brings uncertainty about their identities. We applied molecular biology techniques--18S rDNA sequencing and fluorescent in situ hybridization (FISH)--to compare this host-parasite system from both environments. The North Sea Amoebophrya sp. 18S rDNA sequence was 89% identical to the previously described Baltic Sea Amoebophrya sp. sequence, suggesting they are different species. In spite of that, a phylogenetical analysis placed the North Sea parasite sequence in a well-supported cluster with other Amoebophrya sp. sequences. The D. norvegica 18S rDNA sequences from both environments were 100% identical, indicating that the hosts have not evolved independently. A DNA probe designed for the Baltic Sea Amoebophrya sp. 18S rRNA was used in FISH assays on infected D. norvegica populations from both environments. The probe stained all infected cells from the Baltic sample, whereas none from the North Sea were stained. The results indicate that D. norvegica is released from one parasite when entering the Baltic Sea, and become less infected by an alternative parasite species.
authors.affiliation: Department of Biology and Environmental Science, Kalmar University, SE 391 82, Kalmar, Sweden. paulo.salomon@hik.se
authors.forename: Paulo S
authors.initials: PS
authors.lastname: Salomon
authors.forename: Sven
authors.initials: S
authors.lastname: Janson
authors.forename: Edna
authors.initials: E
authors.lastname: Granéli
mesh_terms: D000818:Animals; D016054:DNA, Protozoan / Q000737:chemistry / Q000302:isolation & purification; D004141:Dinoflagellida / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification*; D006790:Host-Parasite Interactions / Q000235:genetics / Q000502:physiology; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012623:Seawater / Q000469:parasitology*; D017422:Sequence Analysis, DNA
chemical_list: D016054:DNA, Protozoan; D012337:RNA, Ribosomal, 18S