中国动物和人类感染的弓形虫分离株的基因型与鼠毒力。
Genotypes and mouse virulence of Toxoplasma gondii isolates from animals and humans in China.
机构信息
Department of Parasitology, Provincial Laboratory of Microbiology & Parasitology, Anhui Medical University, Hefei, Anhui, China.
出版信息
PLoS One. 2013;8(1):e53483. doi: 10.1371/journal.pone.0053483. Epub 2013 Jan 7.
BACKGROUND
Recent population structure studies of T. gondii revealed that a few major clonal lineages predominated in different geographical regions. T. gondii in South America is genetically and biologically divergent, whereas this parasite is remarkably clonal in North America and Europe with a few major lineages including Types I, II and III. Information on genotypes and mouse virulence of T. gondii isolates from China is scarce and insufficient to investigate its population structure, evolution, and transmission.
METHODOLOGY/PRINCIPAL FINDINGS: Genotyping of 23 T. gondii isolates from different hosts using 10 markers for PCR-restriction fragment length polymorphism analyses (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) revealed five genotypes; among them three genotypes were atypical and two were archetypal. Fifteen strains belong to the Chinese 1 lineage, which has been previously reported as a widespread lineage from swine, cats, and humans in China. Two human isolates fall into the type I and II lineages and the remaining isolates belong to two new atypical genotypes (ToxoDB#204 and #205) which has never been reported in China. Our results show that these genotypes of T. gondii isolates are intermediately or highly virulent in mice except for the strain TgCtwh6, which maintained parasitemia in mice for 35 days post infection although it possesses the uniform genotype of Chinese 1. Additionally, phylogenetic network analyses of all isolates of genotype Chinese 1 are identical, and there is no variation based on the sequence data generated for four introns (EF1, HP2, UPRT1 and UPRT7) and two dense granule proteins (GRA6 and GRA7).
CONCLUSION/SIGNIFICANCE: A limited genetic diversity was found and genotype Chinese 1 (ToxoDB#9) is dominantly circulating in mainland China. The results will provide a useful profile for deep insight to the population structure, epidemiology and biological characteristics of T. gondii in China.
背景
最近对刚地弓形虫的种群结构研究表明，少数几个主要的无性系在不同的地理区域占主导地位。南美洲的刚地弓形虫在遗传和生物学上存在差异，而在北美的寄生虫非常克隆，主要有几个谱系，包括 I 型、II 型和 III 型。关于中国的刚地弓形虫分离株的基因型和小鼠毒力的信息很少，不足以调查其种群结构、进化和传播。
方法/主要发现：使用 10 个 PCR 限制性片段长度多态性分析（SAG1、SAG2、SAG3、BTUB、GRA6、c22-8、c29-2、L358、PK1 和 Apico）对来自不同宿主的 23 株刚地弓形虫进行基因分型，结果显示有 5 种基因型；其中 3 种为非典型基因型，2 种为典型基因型。15 株属于中国 1 谱系，该谱系此前曾在中国的猪、猫和人类中广泛报道。两例人类分离株属于 I 型和 II 型，其余分离株属于两种新的非典型基因型（ToxoDB#204 和#205），在中国从未报道过。我们的结果表明，除了 TgCtwh6 株外，这些刚地弓形虫分离株在小鼠中的毒力为中等或高度，尽管它具有中国 1 型的均匀基因型，但在感染后 35 天仍保持寄生虫血症。此外，所有基因型中国 1 的分离株的系统发生网络分析是相同的，根据生成的四个内含子（EF1、HP2、UPRT1 和 UPRT7）和两个致密颗粒蛋白（GRA6 和 GRA7）的序列数据没有变化。
结论/意义：发现遗传多样性有限，中国 1 型（ToxoDB#9）在中国大陆占主导地位。研究结果将为深入了解中国刚地弓形虫的种群结构、流行病学和生物学特征提供有用的信息。
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