TY - JOUR T1 - Mikrocytos roughleyi taxonomic affiliation leads to the genus Bonamia (Haplosporidia) A1 - Cochennec,Nathalie A1 - Reece,K. A1 - Berthe,Franck A1 - Hine,Mike AD - IFREMER, Lab Genet & Pathol, F-17390 La Tremblade, France. AD - Virginia Inst Marine Sci, Aquaculture Genet & Breeding Technol Ctr, Gloucester Point, VA 23062 USA. AD - MAF Operat, Natl Ctr Dis Invest, Aquat Anim Dis, Wellington 6007, New Zealand. UR - https://archimer.ifremer.fr/doc/00000/2816/ DO - 10.3354/dao054209 KW - Small subunit rDNA KW - Taxonomy KW - Microcell KW - Bonamosis KW - Saccostrea glomerata KW - Mikrocytos roughleyi N2 - Microcell-type parasites of oysters are associated with a complex of diseases in different oyster species around the world. The etiological agents are protists of very small size that are very difficult to characterize taxonomically. Associated lesions may vary according to the host species, and their occurrence may be related to variations in tissue structure. Lesion morphology cannot be used to distinguish the different agents involved. Ultrastructural observations on Mikrocytos roughleyi revealed similarities with Bonamia spp., particularly in regard to the presence of electron-dense haplosporosomes and mitochondria, whose absence from M mackini also indicate that M roughleyi and M mackini are not congeneric. A partial small subunit (ssu) rRNA gene sequence of M roughleyi was determined. This partial sequence, 951 nucleotides in length, has 95.2 and 98.4% sequence similarities with B. ostreae and B. exitiosus ssu rDNA sequences, respectively. Polymorphisms among the ssu rDNA sequences of B. ostreae, B. exitiosus and M roughleyi allowed identification of restriction enzyme digestion patterns diagnostic for each species. Phylogenetic analysis based on the ssu rDNA data suggested that M roughleyi belongs in the phylum Haplosporidia and that it is closely related to Bonamia spp. On the basis of ultrastructural and molecular considerations, M roughleyi should be considered a putative member of the genus Bonamia. Y1 - 2003/04 PB - Inter-Research JF - Diseases of aquatic organisms SN - 0177-5103 VL - 54 IS - 3 SP - 209 EP - 217 ID - 2816 ER -