Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi, MS, 39762, USA.
Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi, MS, 39762, USA.
Acta Parasitol. 2020 Jun;65(2):388-395. doi: 10.2478/s11686-020-00172-8. Epub 2020 Feb 12.
Myxidium kudoi Meglitsch, 1937 has been described from the type host, blue catfish Ictalurus furcatus, with no additional host records or molecular data available for this species.
To provide molecular data and a novel host locality for this species and carry out phylogenetic analyses to infer the evolutionary relationship of the species to other members of the family Myxidiidae for which DNA sequence data is available.
These data were collected using myxospores from the gallbladder of a blue catfish, Ictalurus furcatus collected from Lake Texoma, Oklahoma, USA. Myxospores were morphologically consistent with the only other account of this species and not any other Myxidium species described from siluriform fishes.
Myxospores were oblong with rounded ends and were 10.8-12.6 (11.6 ± 0.5) µm in length and 4.7-6.6 (5.7 ± 0.5) µm in width. Polar capsules were subspherical and 2.7-3.9 (3.4 ± 0.3) µm in length and 2.4-3.5 (3.1 ± 0.3) µm in diameter, with each capsule containing a polar filament with 3-4 coils. Molecular data consisted of a 2918-bp sequence of the partial 18S, complete ITS1, 5.8S, ITS2, and partial 28S ribosomal rRNA regions as well as a 2455-bp sequence of partial 28S ribosomal RNA. The partial 18S and 28S data was used in a concatenated Bayesian phylogenetic analysis to further infer the evolutionary relationships of the Myxidiidae. Additionally, the partial 18S data was used in a separate phylogenetic analysis.
The present work reports novel morphological and molecular data for Myxidium kudoi as well as a novel locality of occurrence for this species. In concatenated phylogenetic analysis using 18S and 28S data and other molecular data from Myxozoa, M. kudoi grouped with other freshwater Myxidiidae. In the single-locus, 18S analysis, M. kudoi grouped with Myxidium rhodei from Rutilus rutilus and Myxidium amazonense from Corydoras melini, the only other Myxidium species of catfish for which molecular data are available.
Myxidium kudoi Meglitsch，1937 曾被描述于其模式宿主蓝鲶（Ictalurus furcatus），此后该物种再无其他宿主记录或分子数据。
为该物种提供分子数据和新的宿主地点，并进行系统发育分析，以推断其与其他具有可用 DNA 序列数据的粘孢子虫科成员的进化关系。
这些数据是使用从美国俄克拉荷马州 Lake Texoma 的蓝鲶胆囊中收集的粘孢子虫获得的。粘孢子虫的形态与该物种的唯一其他描述一致，而与从鲶形目鱼类中描述的任何其他 Myxidium 物种都不一致。
粘孢子虫呈长圆形，两端圆润，长 10.8-12.6（11.6±0.5）μm，宽 4.7-6.6（5.7±0.5）μm。极囊呈近球形，长 2.7-3.9（3.4±0.3）μm，宽 2.4-3.5（3.1±0.3）μm，每个囊内含有一条带有 3-4 个线圈的极丝。分子数据由部分 18S、完整 ITS1、5.8S、ITS2 和部分 28S 核糖体 rRNA 区域的 2918bp 序列以及部分 28S 核糖体 RNA 的 2455bp 序列组成。部分 18S 和 28S 数据用于联合贝叶斯系统发育分析，以进一步推断粘孢子虫科的进化关系。此外，部分 18S 数据用于单独的系统发育分析。
本研究报告了 Myxidium kudoi 的新形态和分子数据以及该物种的新发生地。在使用 18S 和 28S 数据以及粘孢子虫其他分子数据进行的联合系统发育分析中，M. kudoi 与其他淡水粘孢子虫科成员聚在一起。在单基因座 18S 分析中，M. kudoi 与鲤科鱼类的 Myxidium rhodei 和脂鲤科鱼类的 Myxidium amazonense 聚在一起，这是其他具有可用分子数据的鲶形目鱼类的唯一 Myxidium 物种。
