Ruybal Paula, Moretta Rosalia, Perez Andres, Petrigh Romina, Zimmer Patricia, Alcaraz Elda, Echaide Ignacio, Torioni de Echaide Susana, Kocan Katherine M, de la Fuente Jose, Farber Marisa
Instituto de Biotecnología, Centro de Investigaciones de Ciencias Veterinarias y Agronómicas, Instituto Nacional de Tecnología Agropecuaria (INTA), Los Reseros y Las Cabañas, CP 1686, Hurlingam, Buenos Aires, Argentina.
Vet Parasitol. 2009 May 26;162(1-2):176-80. doi: 10.1016/j.vetpar.2009.02.006. Epub 2009 Feb 12.
Bovine anaplasmosis caused by Anaplasma marginale is a worldwide major constraint to cattle production. The A. marginale major surface protein 1 alpha (msp1alpha) gene contains a variable number of tandem repeats in the amino terminal region and has been used for the characterization of pathogen genetic diversity. This study reports the first characterization of A. marginale genetic diversity in Argentina based on msp1alpha genotypes and its putative relationship with Rhipicephalus (Boophilus) microplus infestations. Herein, we analyzed whole blood bovine samples from anaplasmosis outbreaks in R. microplus infested (9 samples) and eradicated/free (14 samples) regions. Sequence analysis revealed the existence of 15 different msp1alpha genotypes with 31 different repeat units. Six new repeat sequences were discovered in this study and 13/31 (42%) repeats were unique to Argentinean strains. The analysis of msp1alpha repeat sequences according to R. microplus infestations resulted in three repeat groups: (i) found in tick-infested regions (20 repeats), (ii) found in tick free regions (6 repeats) and (iii) randomly distributed (5 repeats). Moreover, A. marginale msp1alpha genetic diversity was higher in tick-infested regions than in tick free areas. These results, together with previous evidence suggesting that A. marginale msp1alpha repeat units co-evolved with the tick vector, might represent an evidence of the role of tick-mediated transmission for the generation of pathogen genetic diversity.
由边缘无形体引起的牛无浆体病是全球范围内牛生产的主要制约因素。边缘无形体主要表面蛋白1α（msp1α）基因在氨基末端区域含有可变数量的串联重复序列，已被用于病原体遗传多样性的表征。本研究报告了基于msp1α基因型对阿根廷边缘无形体遗传多样性的首次表征及其与微小扇头蜱（牛蜱）感染的推定关系。在此，我们分析了来自微小扇头蜱感染地区（9份样本）和已根除/无蜱地区（14份样本）无浆体病暴发的全血牛样本。序列分析揭示了存在15种不同的msp1α基因型，具有31个不同的重复单元。本研究发现了6个新的重复序列，31个重复序列中有13个（42%）是阿根廷菌株所特有的。根据微小扇头蜱感染情况对msp1α重复序列进行分析，得到三个重复组：（i）在蜱感染地区发现的（20个重复序列），（ii）在无蜱地区发现的（6个重复序列）和（iii）随机分布的（5个重复序列）。此外，边缘无形体msp1α的遗传多样性在蜱感染地区高于无蜱地区。这些结果，连同先前表明边缘无形体msp1α重复单元与蜱传播媒介共同进化的证据，可能代表了蜱介导的传播在病原体遗传多样性产生中的作用的证据。
