Campbell S R, van Keulen H, Erlandsen S L, Senturia J B, Jarroll E L
Department of Biology, Cleveland State University, Ohio 44115.
Exp Parasitol. 1990 Nov;71(4):470-82. doi: 10.1016/0014-4894(90)90073-l.
Species in the genus Giardia have been named on the basis of host specificity, cell dimensions, and median body morphology. Despite these criteria, the species taxonomy of Giardia is still in question. To investigate Giardia taxonomy on a molecular level, Giardia chromosomal DNA was analyzed by orthogonal-field-alternation gel electrophoresis (OFAGE) and transverse alternating field electrophoresis (TAFE). Chromosomal DNA of G. duodenalis isolates (human, muskrat, sheep, dog, beaver), G. muris (mouse), and G. ardeae (great blue heron) were subjected to OFAGE and TAFE analyses. Comparable DNA patterns were obtained by both electrophoretic methods, but OFAGE required 8 days while TAFE required only 3 days. DNA patterns among all G. duodenalis isolates, although quite similar to each other, were distinctly different from those of G. muris and G. ardeae; G. muris and G. ardeae DNA patterns were distinctly different from each other. A G. duodenalis (Portland 1) total DNA probe hybridized to the DNA of all G. duodenalis isolates on Southern blots, but not detectably to G. muris and G. ardeae DNA. Similarly, G. muris and G. ardeae total DNA probes only hybridized detectably to their respective DNA. One probe that appears to hybridize to the DNA of all G. duodenalis and to G. ardeae DNA rather than G. muris DNA has been developed. Another probe that hybridizes only to G. muris and G. ardeae DNA has been developed. These data suggest that the differentiation of Giardia isolated from host and environmental samples may eventually be accomplished by DNA probes. Additionally, these techniques perhaps combined with other criteria may lead to the establishment of a sound taxonomic scheme for this genus.
贾第虫属的物种是根据宿主特异性、细胞大小和中体形态来命名的。尽管有这些标准，但贾第虫的物种分类仍存在疑问。为了在分子水平上研究贾第虫的分类，通过正交交变电场凝胶电泳（OFAGE）和横向交变电场电泳（TAFE）对贾第虫染色体DNA进行了分析。对十二指肠贾第虫分离株（人、麝鼠、绵羊、狗、海狸）、鼠贾第虫（小鼠）和苍鹭贾第虫（大蓝鹭）的染色体DNA进行了OFAGE和TAFE分析。两种电泳方法都获得了可比的DNA图谱，但OFAGE需要8天，而TAFE只需要3天。所有十二指肠贾第虫分离株的DNA图谱虽然彼此非常相似，但与鼠贾第虫和苍鹭贾第虫的图谱明显不同；鼠贾第虫和苍鹭贾第虫的DNA图谱彼此也明显不同。十二指肠贾第虫（波特兰1）总DNA探针在Southern杂交中与所有十二指肠贾第虫分离株的DNA杂交，但未检测到与鼠贾第虫和苍鹭贾第虫DNA杂交。同样，鼠贾第虫和苍鹭贾第虫总DNA探针仅能检测到与其各自的DNA杂交。已经开发出一种似乎能与所有十二指肠贾第虫和苍鹭贾第虫DNA而非鼠贾第虫DNA杂交的探针。另一种仅与鼠贾第虫和苍鹭贾第虫DNA杂交的探针也已开发出来。这些数据表明，从宿主和环境样本中分离的贾第虫的分化最终可能通过DNA探针来完成。此外，这些技术可能与其他标准相结合，从而为该属建立一个合理的分类方案。
