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Hayashi K, Kitayama C, Saito T, Ohari Y, Hayashi K, Kondo S, Takashima Y, Kuroki T, Shibahara T, Itagaki T. Detection and molecular characteristics of Pyelosomum cochlear (Digenea: Pronocephalidae) in the urinary bladder of the green sea turtle (Chelonia mydas) in the Northwest Pacific Ocean. INFECTION GENETICS AND EVOLUTION 2021; 93:104962. [PMID: 34111570 DOI: 10.1016/j.meegid.2021.104962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/20/2021] [Accepted: 06/02/2021] [Indexed: 11/17/2022]
Abstract
The genus Pyelosomum consists of parasitic flukes occurring primarily in marine turtles; Pyelosomum cochlear Looss 1899 is the only species of this genus that parasitizes the urinary bladder. In this study, we detected flukes in the urinary bladders of 20 of 88 green sea turtles (Chelonia mydas) harvested in the Ogasawara Islands, in the Northwest Pacific Ocean. We identified the flukes as P. cochlear based on detailed morphological observations and comparisons of morphometric measurements of the species reported previously. Nucleotide sequences of nuclear ribosomal 18S and 28S regions and the mitochondrial cytochrome c oxidase subunit 1 (COI) region were determined for the flukes. The 18S and 28S phylogenetic trees revealed that the species of the superfamily Pronocephaloidea, including P. cochlear, constituted a single clade, but the species of the family Pronocephalidae did not constitute a single taxon. These findings suggest that Pronocephalidae is a paraphyletic group. The COI sequences of P. cochlear exhibited high genetic diversity, suggesting that they would be useful markers to understand the genetic structure of the parasite and its evolutionary relationship with the host turtle populations. This is the first study to provide the nucleotide sequences of Pyelosomum species; these data will be available for further molecular studies of this genus and its related taxa.
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Affiliation(s)
- Kei Hayashi
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoinooka, Imabari 794-8555, Japan
| | - Chiyo Kitayama
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Ogasawara, Tokyo 100-2101, Japan
| | - Taizo Saito
- The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Yuma Ohari
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku Sapporo, Hokkaido 060-0818, Japan
| | - Kaoru Hayashi
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoinooka, Imabari 794-8555, Japan
| | - Satomi Kondo
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Ogasawara, Tokyo 100-2101, Japan
| | - Yasuhiro Takashima
- The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Department of Veterinary Parasitological Diseases, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan
| | - Toshiro Kuroki
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoinooka, Imabari 794-8555, Japan
| | - Toshiyuki Shibahara
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoinooka, Imabari 794-8555, Japan
| | - Tadashi Itagaki
- Laboratory of Veterinary Parasitology, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka 020-8550, Japan.
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