Vector and Waterborne Pathogens Research Group, Harry Butler Institute, Murdoch University, Murdoch, Western Australia, 6150, Australia.
Australian National Phenome Centre, Health Futures Institute, Murdoch University, Harry Perkins Building, Perth, Western Australia, 6150, Australia.
Parasitol Res. 2021 Mar;120(3):1037-1047. doi: 10.1007/s00436-021-07046-6. Epub 2021 Jan 18.
A new coccidian species, Isospora lugensae n. sp., was described from a single Kerguelen petrel (Lugensa brevirostris). Sporulated oocysts (n = 25) were characterized as subspheroidal to ellipsoidal measuring 24-25 μm × 21-23 μm (24.8 × 22.2 μm) in length/width (L/W), respectively, with a ratio of 1.07-1.14 μm (1.12). They contained a bi-layered wall with a thickness of 0.8-1.2 μm (1.0) and the outer layer smooth, with c.2/3 of total thickness. The oocyst contained two polar granules with both micropyle and oocyst residuum absent. Ovoidal sporocysts (n = 25) measured 15-16 μm × 10-11 μm (15.7 × 10.8 μm) in L/W, with a ratio of 1.41-1.49 μm (1.46). A flattened to knob-like Stieda body was present (c.0.5 μm deep × 2.5 μm wide) as well as a rounded to trapezoidal sub-Stieda (c.1.5 μm deep × 3.0 μm wide); however, no para-Stieda body was detected. The sporocyst residuum was composed of scattered spherules of different sizes, while vermiform sporozoites contained a refractile body, nucleus and visible striations. Analysis of the full-length mitochrondrial (mtDNA) genome revealed 3 protein-coding genes, (CytB, COI and COIII), 18 LSU and 14 small subunit (SSU) rDNA fragments, without transfer RNA genes with a total length of 6257 bp. Phylogenetic analysis of genomic SSU ribosomal sequences indicated that Isospora lugensae n. sp. is genetically similar to Eimeria reichenowi, isolated from a red-crowned crane (Grus japonensis) from Japan, with a 96.6% homology. The mtDNA sequence is most similar to Isospora serinuse with a 95.8% genetic similarity. Based on morphological and molecular data, this isolate is a new species of coccidian parasite that to date has only been found in a Kerguelen petrel.
一种新的等孢球虫种，Isospora lugensae n. sp.，是从一只 Kerguelen 信天翁（Lugensa brevirostris）中描述的。孢子化卵囊（n=25）呈亚球形到椭圆形，长径和短径分别为 24-25μm×21-23μm（24.8μm×22.2μm），长宽比为 1.07-1.14μm（1.12）。它们具有双层壁，厚度为 0.8-1.2μm（1.0），外层光滑，占总厚度的约 2/3。卵囊内含有两个极粒，均无微口和卵囊残余物。卵囊内含有 25 个卵形孢子囊，长径和短径分别为 15-16μm×10-11μm（15.7μm×10.8μm），长宽比为 1.41-1.49μm（1.46）。存在一个扁平到圆头状的斯泰达体（深约 0.5μm，宽 2.5μm）和一个圆形到梯形的亚斯泰达体（深约 1.5μm，宽 3.0μm）；然而，没有检测到副斯泰达体。孢子囊残余物由不同大小的散在的球体组成，而蠕虫状的孢子含有一个折光体、细胞核和可见的条纹。全长线粒体（mtDNA）基因组分析显示了 3 个蛋白编码基因（CytB、COI 和 COIII）、18 个 LSU 和 14 个小亚基（SSU）rDNA 片段，没有转移 RNA 基因，总长度为 6257bp。基因组 SSU 核糖体序列的系统发育分析表明，Isospora lugensae n. sp. 在遗传上与从日本红冠鹤（Grus japonensis）中分离的 Eimeria reichenowi 相似，同源性为 96.6%。mtDNA 序列与 Isospora serinuse 最相似，遗传相似度为 95.8%。基于形态学和分子数据，该分离株是一种新的等孢子球虫寄生虫，迄今为止仅在一只 Kerguelen 信天翁中发现。
