title: Ultrastructure and molecular phylogeny of Mesodinium coatsi sp. nov., a benthic marine ciliate.
abstract: Mesodinium is a globally distributed ciliate genus forming frequent and recurrent blooms in diverse marine habitats. Here, we describe a new marine species, Mesodinium coatsi n. sp., originally isolated from interstitial water of surface sand samples collected at Mohang Beach, Korea. The species was maintained under a mixotrophic growth condition for longer than 1 yr by providing a cryptomonad, Chroomonas sp., as the sole prey. Cell morphology and subcellular structure were examined by light microscopy, scanning, and transmission electron microscopy, and molecular phylogeny was inferred from nuclear-encoded 18S rDNA sequence data. Like other Mesodinium species, M. coatsi consisted of two hemispheres separated by two types of kinetids, and had tentacles located at the oral end of the cell. Several food vacuoles were observed in the cytoplasm, and partially digested prey cells sometimes existed in food vacuoles. Kinetids and the associated accessory structures were quite similar to those previously reported, but M. coatsi was differentiated from other marine Mesodinium species by ultrastructural characters of the dikinetids, polykinetids, and tentacles. We also provided a detailed illustration of infraciliature. Molecular phylogeny revealed that M. coatsi and Mesodinium chamaeleon were closely related to each other.
authors.affiliation: Department of Biology, Chungnam National University, Daejeon, 305-764, Korea.
authors.forename: Seung Won
authors.initials: SW
authors.lastname: Nam
authors.forename: Woongghi
authors.initials: W
authors.lastname: Shin
authors.forename: Misun
authors.initials: M
authors.lastname: Kang
authors.forename: Wonho
authors.initials: W
authors.lastname: Yih
authors.forename: Myung Gil
authors.initials: MG
authors.lastname: Park
mesh_terms: D059001:Aquatic Organisms / Q000145:classification / Q000235:genetics / Q000648:ultrastructure*; D016798:Ciliophora / Q000145:classification / Q000235:genetics / Q000648:ultrastructure*; D044785:Cryptophyta; D020387:Food Chain; D020459:Genes, rRNA; D015388:Organelles / Q000502:physiology / Q000648:ultrastructure*; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D012337:RNA, Ribosomal, 18S
keywords: Mesodinium coatsi; infraciliature; mixotrophic; taxonomy