Laboratory of Parasitology, Joint Graduate School of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan.
Laboratory of Parasitology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan.
Parasitol Res. 2022 Feb;121(2):601-612. doi: 10.1007/s00436-021-07418-y. Epub 2022 Jan 10.
Multiple Kudoa spp. (Myxozoa: Myxosporea: Multivalvulida) have been recorded in Japanese parrotfish (Calotomus japonicus) from the Philippine Sea (Northwest Pacific Ocean), off southwestern Japan; Kudoa yasunagai in the brain, and K. igami, K. lateolabracis, and K. thalassomi in the muscles. This study examined eight Philippine Sea Japanese parrotfish samples collected in January and February 2019 and found K. prunusi in the brain (3-57 plasmodia/fish; average 17.9) and K. lateolabracis plasmodia in the trunk muscle of all fish individuals examined. The K. prunusi in this study was characterized by myxospores predominatetly with six shell valves (SVs) and a corresponding number of polar capsules (PCs), contrasting with the original description of the species from farmed Pacific bluefin tuna (Thunnus orientalis) brain that characterized the species as having predominately five SVs/PCs. Molecular-genetic characterization of 18S and 28S ribosomal RNA genes and mitochondrial DNA genes (cytochrome c oxidase subunit 1 and small and large ribosomal RNA subunits) clearly differentiated the K. prunusi isolate from K. yasunagai, commonly characterized by six or seven, but rarely five, SVs/PCs myxospores. The Japanese parrotfish is a new host record for K. prunusi and speculated to be an important reservoir host in its natural waters. Kudoa lateolabracis myxospores isolated from pseudocysts in the myofiber were morphologically and phylogenetically close to a clade of the Kudoa spp. that exhibit cruciform myxospores similar to K. thyrsites. This study is the first to sequence a mitochondrial DNA of small and large subunit ribosomal RNA of K. lateolabracis.
多种 Kudoa 种（粘孢子虫门：多瓣目：多瓣科）已在来自菲律宾海（西北太平洋）的日本鹦嘴鱼（Calotomus japonicus）中被记录，该鱼分布于日本西南部；脑中有 Kudoa yasunagai，肌肉中有 K. igami、K. lateolabracis 和 K. thalassomi。本研究检查了 2019 年 1 月和 2 月采集的 8 个菲律宾海日本鹦嘴鱼样本，发现脑中有 K. prunusi（3-57 个孢子/鱼；平均 17.9），所有检查的鱼个体的躯干肌肉中都有 K. lateolabracis 孢子。本研究中的 K. prunusi 的特点是粘孢子主要有 6 个壳瓣（SVs）和相应数量的极囊（PCs），与从养殖的太平洋蓝鳍金枪鱼（Thunnus orientalis）脑中描述的该物种形成对比，该物种的特点是主要有 5 个 SVs/PCs。18S 和 28S 核糖体 RNA 基因和线粒体 DNA 基因（细胞色素 c 氧化酶亚单位 1 和小、大亚基核糖体 RNA 亚单位）的分子遗传特征清楚地区分了 K. prunusi 分离株和常见的 6 或 7 个、但很少 5 个 SVs/PCs 粘孢子的 K. yasunagai。日本鹦嘴鱼是 K. prunusi 的新宿主记录，推测在其自然水域中是一个重要的储存宿主。从肌纤维中的假囊泡中分离出的 Kudoa lateolabracis 粘孢子在形态和系统发育上与表现出类似 Kudoa thyrsites 的十字形粘孢子的 Kudoa 种的一个分支密切相关。本研究首次对 Kudoa lateolabracis 的小、大亚基核糖体 RNA 的线粒体 DNA 进行了测序。
