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PHYLOGENETIC AND TAXONOMIC STUDY OF SUBTERRANEAN WATER PROTISTS.

地下水原生生物的系统发育和分类学研究。

基本信息

批准号：
10836001
负责人：
HORIGUCHI Takeo
金额：
$ 2.18万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The subterranean water protists in sandy beach, especially dinoflagellates were investigated by means of light and electron microscopy and their phylogenetic affinities were studied using a molecular phylogenetic techniques. The sampling locality was at Ishikari Beach in Ishikari City, Hokkaido, Japan and samplings were made on a monthly basis. At the time of sampling, water temperature and salinity were also recorded. The salinity of the subterranean habitat in sandy beach seemed to be affected by both seawater and freshwater from inland. Despite it unstable salinity conditions, many species of dinoflagellates were found to inhabit there. By the taxonomic survey, I was able to demonstrate presence of various dinoflagellates, including Amphidinium (11 spp.), Gymnodinium (5 spp.), Gyrodinium (3 spp.), Katodinium (4 spp.), Oxyrrhis (1 sp.), Sinophysis (1 sp.) and Roscoffia (1 sp,). Nearly half of them were found to be new species and formal taxonomic descriptions will be published elsewhere.To assess the phylogenetic affinities of these dinoflagellate, single-cell PCR method was employed to amplify 18S rRNA gene. Use of low temperature and longer annealing time were found to be effective to successfully amplify the gene, but it was not always successful. Almost complete sequence of Gyrodinium viridescens was obtained and this together with those of other dinoflagellates downloaded from DDBJ as well as our own data were aligned and phylogenetic trees were constructed with various phylogenetic methods. The results indicated that G, viridescens was included in the photosynthetic Amphidinium clade. This seems to indicate that G. viridescens had secondarily lost its plastid and later acquired Gyrodinium-type morphology.

利用光学显微镜和电子显微镜对桑迪海滩的地下水原生生物进行了研究，并利用分子系统学方法对它们的亲缘关系进行了分析。采样地点为日本北海道石狩市的石狩海滩，每月进行采样。在取样时，还记录了水温和盐度。桑迪海滩地下生境的盐度似乎受到来自内陆的海水和淡水的共同影响。尽管盐度条件不稳定，但发现许多种类的甲藻栖息在那里。通过分类调查，我能够证明各种甲藻的存在，包括前沟藻（11种），裸盖藻（5种），旋甲藻属（3种），Katodinium（4 spp.），Oxyrrhis（1 sp.），中华扁藻（Sinophysis）1种和Roscoffia（1 sp，）。为了研究这些甲藻的系统发育关系，采用单细胞PCR方法扩增了18SrRNA基因。发现使用低温和较长的退火时间可以有效地成功扩增基因，但并不总是成功的。获得了几乎完整的Gyrodinium viridescens序列，并将其与DDBJ下载的其他甲藻以及我们自己的数据进行比对，并用各种系统发育方法构建了系统发育树。结果表明，绿甲藻属于光合前沟藻分支。这似乎表明G. viridescens其次失去了质体，后来获得了Gyrodinium型形态。