PDF(Sci-hub)
Abstract：
A great deal of evidence demonstrates that a strongly clonal population structure of Toxoplasma gondii strains exists in humans and animals in North America and Europe, while the strains from South America are genetically separate and more diverse. Potential differences in virulence between different strains mean that an understanding of strain diversity is important to human and animal health. However, to date, only one predominant genotype, ToxoDB#9 (Chinese I), and a few other genotypes, including ToxoDB#205, have been identified in China. By using DNA sequence-based phylogenetic analyses, we have re-evaluated the population structure of T. gondii strains collected from China and compared them with other global strains. Based on phylogenetic analysis of restriction fragment length polymorphisms, multilocus sequence typing and intron sequences from T. gondii, we propose that the Chinese isolates described as Chinese I are divided into two groups called Chinese I and Chinese III. Our results demonstrate that significant differences were found in mouse mortality caused by some Chinese strains, and also the archetypal I, II, III strains in mice. Furthermore, a comparison of cyst loading in the brains of infected rats showed some Chinese strains to be capable of a high degree of cyst formation. Furthermore we show that genotyping using neutral genetic markers may not be a useful predictor of pathogenic phenotypes.
摘要：
大量证据表明，在北美和欧洲的人类和动物中存在弓形虫菌株的强克隆种群结构，而来自南美的菌株在基因上是分开的，而且更加多样化。不同菌株之间毒力的潜在差异意味着对菌株多样性的理解对人类和动物健康很重要。然而,到目前为止,只有一个主要基因型，ToxoDB#9(中文I),和其他一些基因型，包括ToxoDB#205，已在中国确定。通过使用基于DNA序列的系统发育分析，我们重新评估了从中国收集的弓形虫菌株的种群结构，并将其与其他全球菌株进行了比较。基于限制性片段长度多态性的系统发育分析，来自弓形虫的多位点序列分型和内含子序列，我们建议将描述为中文I的中文分离株分为两组，称为中文I和中文III。我们的结果表明，一些中国品系引起的小鼠死亡率存在显着差异，还有原型I,II,小鼠中的III株。此外，感染大鼠大脑中囊肿负荷的比较表明，某些中国菌株能够高度形成囊肿。此外，我们表明使用中性遗传标记进行基因分型可能不是致病表型的有用预测因子。
