Ellis J T, Holmdahl O J, Ryce C, Njenga J M, Harper P A, Morrison D A
Department of Cell & Molecular Biology, University of Technology, Sydney, NSW, Australia.
Protist. 2000 Dec;151(4):329-36. doi: 10.1078/S1434-4610(04)70031-0.
Knowledge on parasites of the genus Besnoitia is sparse, which are classified in the subfamily Toxoplasmatinae of the phylum Apicomplexa. This arrangement hypotheses that Besnoitia represents the sister group to species such as Toxoplasma gondii and Hammondia hammondi. In order to test this hypothesis, phylogenetic analyses of 18S ribosomal DNA (rDNA) from Besnoitia, Hammondia, Isospora, Frenkelia, Eimeria, Neospora, Sarcocystis and Toxoplasma were performed. The 18S rDNA of Besnoitia besnoiti, Besnoitia jellisoni and Eimeria alabamensis were amplified by PCR and sequenced. Phylogenetic analyses by parsimony and maximum-likelihood methods showed Besnoitia to be reproducibly the sister group to a clade containing Hammondia, Neospora and Toxoplasma. Furthermore, Besnoitia of cattle, wildebeest and goats had identical ITS1 rDNA sequences, which questions the use of the taxon Besnoitia caprae to describe the Besnoitia found in goats.
关于贝斯诺虫属（Besnoitia）寄生虫的知识匮乏，该属被归类于顶复门（Apicomplexa）的弓形虫亚科（Toxoplasmatinae）。这种分类假设贝斯诺虫属是刚地弓形虫（Toxoplasma gondii）和哈蒙德氏球虫（Hammondia hammondi）等物种的姐妹群。为了验证这一假设，对来自贝斯诺虫属、哈蒙德氏球虫属、等孢球虫属（Isospora）、弗伦克球虫属（Frenkelia）、艾美耳球虫属（Eimeria）、新孢子虫属（Neospora）、肉孢子虫属（Sarcocystis）和弓形虫属的18S核糖体DNA（rDNA）进行了系统发育分析。通过聚合酶链反应（PCR）扩增并测序了贝氏贝斯诺虫（Besnoitia besnoiti）、杰氏贝斯诺虫（Besnoitia jellisoni）和阿拉巴马艾美耳球虫（Eimeria alabamensis）的18S rDNA。简约法和最大似然法的系统发育分析表明，贝斯诺虫属可重复性地成为包含哈蒙德氏球虫属、新孢子虫属和弓形虫属的一个进化枝的姐妹群。此外，牛、角马和山羊的贝斯诺虫属具有相同的ITS1 rDNA序列，这对使用山羊贝斯诺虫（Besnoitia caprae）这一分类单元来描述在山羊中发现的贝斯诺虫提出了质疑。
