Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, 0033 Oslo, Norway.
Parasitol Res. 2012 Mar;110(3):1225-37. doi: 10.1007/s00436-011-2619-6. Epub 2011 Aug 19.
Sarcocysts were isolated from the muscle tissue of three roe deer from southeastern Norway and examined by light microscopy, scanning electron microscopy and/or sequencing of the small subunit ribosomal RNA (ssu rRNA) gene. By light microscopy, four sarcocyst types were found, including those of Sarcocystis gracilis and Sarcocystis oviformis, which had been characterized previously. The third cyst type had about 10 μm long, flexible, hair-like surface protrusions, consistent with those of Sarcocystis capreolicanis, and differed genetically from other known species. The name S. capreolicanis was therefore assigned to this sequence type. The fourth cyst type had densely packed, upright, finger-like surface protrusions, about 8 μm long, and was morphologically similar to an unnamed Sarcocystis sp. reported from roe deer in other countries, and identical at the ssu rRNA gene to Sarcocystis sp. Type D previously reported from moose. This species was assigned the new name Sarcocystis silva. Both S. capreolicanis and S. silva displayed considerable intraspecific variation at the ssu rRNA gene. In phylogenetic analyses based on ssu rRNA gene sequences, S. capreolicanis grouped together with other canine-transmitted Sarcocystis species, whereas S. silva was most closely related to Sarcocystis rangiferi and Sarcocystis tarandi of reindeer. Roe deer muscles containing numerous cysts of S. gracilis were fed to a silver fox (Vulpes vulpes) and a blue fox (Vulpes lagopus), both of which started shedding Sarcocystis sporocysts in their faeces 9 days later, and harboured numerous oocysts, measuring about 20 × 15 μm, in their intestinal mucosa upon euthanasia 14 days post-inoculation. DNA derived from these oocysts was amplified and sequenced at the ssu rRNA gene and belonged to S. gracilis, confirming for the first time by molecular methods that foxes are definitive hosts for this species.
从挪威东南部的三只狍子的肌肉组织中分离出肉孢子虫，并用光学显微镜、扫描电子显微镜和/或小亚基核糖体 RNA (ssu rRNA) 基因测序进行检查。通过光学显微镜，发现了四种肉孢子虫类型，包括先前已被描述的 Sarcocystis gracilis 和 Sarcocystis oviformis。第三种囊泡类型具有约 10 μm 长的、灵活的、毛发状的表面突起，与 Sarcocystis capreolicanis 的一致，并且在遗传上与其他已知物种不同。因此，将该序列类型命名为 S. capreolicanis。第四种囊泡类型具有密集排列的、直立的、指状的表面突起，约 8 μm 长，形态上与其他国家报道的来自狍子的未命名的 Sarcocystis sp. 相似，并且与先前从驼鹿中报道的 Sarcocystis sp. Type D 在 ssu rRNA 基因上完全相同。该物种被赋予新名称 Sarcocystis silva。S. capreolicanis 和 S. silva 在 ssu rRNA 基因上显示出相当大的种内变异。基于 ssu rRNA 基因序列的系统发育分析表明，S. capreolicanis 与其他犬传播的肉孢子虫物种聚集在一起，而 S. silva 与驯鹿的 Sarcocystis rangiferi 和 Sarcocystis tarandi 最为密切相关。含有大量 S. gracilis 囊泡的狍子肌肉被喂给一只银狐（Vulpes vulpes）和一只蓝狐（Vulpes lagopus），两者在 9 天后开始在粪便中排出肉孢子虫孢子囊，并在接种后 14 天安乐死时在其肠黏膜中寄生了大量大小约为 20 × 15 μm 的卵囊。从这些卵囊中提取的 DNA 在 ssu rRNA 基因上进行扩增和测序，属于 S. gracilis，这是首次通过分子方法证实狐狸是该物种的终末宿主。
