Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz - UESC, Rodovia Ilhéus-Itabuna, km 16, Salobrinho, Ilhéus, BA 45662-000, Brazil.
Vet Parasitol. 2012 Oct 26;189(2-4):153-61. doi: 10.1016/j.vetpar.2012.04.036. Epub 2012 May 3.
This study genetically Toxoplasma gondii isolates obtained from pigs intended for human consumption in northeastern Brazil; multilocus PCR-RFLP and sequencing techniques were utilized. Bioassays were conducted using the brain and tongue of 20 pig heads purchased at butcher shops in the city of Ilheus, Bahia, Brazil. Overall, 11 T. gondii isolates designated TgPgBr06-16 were identified. Application of multilocus PCR-RFLP with seven molecular markers (SAG1, SAG2, SAG3, BTUB, C22-8, PK1 and Apico) identified six different genotypes. Isolates TgPgBr 06, 08, 11, 12, 14 and 15 were indistinguishable by this technique, forming a single genotype; the remaining isolates were characterized as distinct genotypes. However, when five genetic markers (SAG1, SAG2, SAG3, BTUB and c22-8) were employed in multilocus PCR-sequencing, all eleven strains of T. gondii were shown to be different. All isolates differed from Type I, II and III clonal genotypes using both genotyping techniques. These results demonstrate that the multilocus PCR-RFLP assay underestimated the true diversity of the T. gondii population in this study. Thus, DNA sequencing is the preferred technique to infer the genetic diversity and population structure of T. gondii strains from Brazil. Moreover, it is necessary to develop new molecular markers to group and characterize atypical T. gondii isolates from South America.
本研究对来自巴西东北部供人类食用的猪的弓形虫分离株进行了基因分析；采用多位点 PCR-RFLP 和测序技术。使用从巴西巴伊亚州伊列乌斯市肉店购买的 20 个头猪的大脑和舌头进行生物测定。总共鉴定出 11 株命名为 TgPgBr06-16 的弓形虫分离株。应用 7 个分子标记（SAG1、SAG2、SAG3、BTUB、C22-8、PK1 和 Apico）的多位点 PCR-RFLP 鉴定出 6 种不同的基因型。分离株 TgPgBr06、08、11、12、14 和 15 无法通过该技术区分，形成单一基因型；其余分离株被表征为不同的基因型。然而，当使用 5 个遗传标记（SAG1、SAG2、SAG3、BTUB 和 c22-8）进行多位点 PCR-测序时，所有 11 株弓形虫均表现出不同。所有分离株均与 I 型、II 型和 III 型克隆基因型不同，两种基因分型技术均如此。这些结果表明，多位点 PCR-RFLP 分析低估了本研究中弓形虫种群的真实多样性。因此，DNA 测序是推断巴西弓形虫株遗传多样性和种群结构的首选技术。此外，有必要开发新的分子标记来对来自南美洲的非典型弓形虫分离株进行分组和特征描述。
