Koch Trine A, Ekelund Flemming
Department of Terrestrial Ecology, Institute of Biology, Copenhagen University, Universitetsparken 15, DK-2100, Copenhagen, Denmark.
Protist. 2005 Jun;156(1):97-112. doi: 10.1016/j.protis.2004.12.001.
The morpho species Bodo designis is widespread and abundant globally in highly contrasting terrestrial and aquatic ecosystems. Whether the forms of Bodo designis from contrasting environments are conspecific, i.e. largely genetically identical, or whether they merely share the external morphology is presently not known. We examined the ability of different strains of Bodo designis isolated from different environments at different geographical sites to survive and grow at a salinity range of 0.5-45%. The Bodo designis strains from marine, freshwater, and terrestrial environments showed a different ability to cope with altered physiological conditions. Most of the tested strains were only able to tolerate a small salinity range, whereas others were able to withstand all tested salinity levels. We further examined the phylogenetic relationship between the different strains by sequencing the small subunit (SSU) rRNA gene. The resulting phylogenetic analyses suggest a huge genetic variation within Bodo designis, and also imply that Dimastigella and Rhyncomonas are developed inside Bodo designis. If the biological species concept is used, the genetic differences as well as the physiological barriers between the different strains of Bodo designis, would suggest that they should be assigned to different species.
形态物种博多设计体（Bodo designis）在全球范围内广泛分布且数量众多，存在于截然不同的陆地和水生生态系统中。目前尚不清楚来自不同环境的博多设计体形态是否为同种，即基因上基本相同，还是仅仅共享外部形态。我们研究了从不同地理地点的不同环境中分离出的不同博多设计体菌株在0.5%-45%盐度范围内生存和生长的能力。来自海洋、淡水和陆地环境的博多设计体菌株应对生理条件变化的能力不同。大多数测试菌株只能耐受较小的盐度范围，而其他菌株则能够承受所有测试的盐度水平。我们通过对小亚基（SSU）rRNA基因进行测序，进一步研究了不同菌株之间的系统发育关系。由此产生的系统发育分析表明，博多设计体内存在巨大的遗传变异，同时也意味着双鞭毛虫属（Dimastigella）和吻滴虫属（Rhyncomonas）是在博多设计体内演化而来的。如果采用生物物种概念，博多设计体不同菌株之间的遗传差异以及生理障碍表明，它们应被归为不同的物种。
