Barta J R, Coles B A, Schito M L, Fernando M A, Martin A, Danforth H D
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Ont., Canada.
Int J Parasitol. 1998 Mar;28(3):485-92. doi: 10.1016/s0020-7519(97)00211-7.
Two laboratory strains from the eastern shore of Maryland 15 years ago and from an Ontario broiler house 23 years ago and three recent field strains of Eimeria maxima (isolated in Maryland, North Carolina and Florida) were examined for phenotypic and genotypic variation using protein profiles, random amplified polymorphic DNA-PCR analysis and DNA sequences obtained from the internal transcribed spacer regions of the rRNA genes. Staining profiles obtained by one-dimensional SDS-PAGE of sporozoite proteins were identical in all five strains. Using random amplified polymorphic DNA-PCR analysis with high %G-C content decamers as primers, we were able to confirm that the five strains are all E. maxima, but were unable to discern any relationships among them because of the limited number of shared polymorphisms identified. In contrast, cloning and sequencing of the internal transcribed spacer-1, 5.8S rDNA and internal transcribed spacer-2 regions of the rRNA genes provided sufficient sequence information to infer phylogenetic relationships among the strains. Almost all of the infraspecific variation was located in the internal transcribed spacer regions. Only two base changes were identified within the 5.8S rRNA gene. Evolutionary relationships among the strains inferred using parsimony analysis of the aligned internal transcribed spacer sequences were well supported, but the hypothesised relationships did not correlate well with the demonstrated immunological cross-reactivities of these strains.
对15年前来自马里兰州东海岸以及23年前来自安大略省一家肉鸡场的两个实验室菌株，和最近的三个巨型艾美耳球虫野外菌株（分别分离自马里兰州、北卡罗来纳州和佛罗里达州），利用蛋白质谱、随机扩增多态性DNA - PCR分析以及从rRNA基因内部转录间隔区获得的DNA序列，检测其表型和基因型变异。通过子孢子蛋白的一维SDS - PAGE获得的染色图谱在所有五个菌株中都是相同的。使用以高%G - C含量的十聚体作为引物的随机扩增多态性DNA - PCR分析，我们能够确认这五个菌株均为巨型艾美耳球虫，但由于鉴定出的共享多态性数量有限，无法辨别它们之间的任何关系。相比之下，rRNA基因内部转录间隔区1、5.8S rDNA和内部转录间隔区2的克隆和测序提供了足够的序列信息来推断菌株之间的系统发育关系。几乎所有种内变异都位于内部转录间隔区。在5.8S rRNA基因内仅鉴定出两个碱基变化。使用比对后的内部转录间隔序列的简约分析推断出的菌株间进化关系得到了充分支持，但假设的关系与这些菌株已证明的免疫交叉反应性相关性不佳。
