Guillou L, Moon-Van Der Staay S Y, Claustre H, Partensky F, Vaulot D
Station Biologique de Roscoff, UPR CNRS 9042, INSU, and Université Pierre et Marie Curie, F-29682 Roscoff Cedex, France.
Appl Environ Microbiol. 1999 Oct;65(10):4528-36. doi: 10.1128/AEM.65.10.4528-4536.1999.
The diversity and abundance of the Bolidophyceae (Heterokonta), a newly described picoplanktonic algal class which is a sister group to the diatoms, was assessed in the equatorial Pacific Ocean and in the Mediterranean Sea by culture isolation, molecular biology techniques, and pigment analyses. Eight strains of Bolidophyceae were isolated in culture from different mesotrophic and oligotrophic areas. The corresponding small subunit (SSU) rRNA gene sequences allowed us to design two probes specific for the Bolidophyceae. These probes have been used in natural samples (i) to selectively amplify and detect Bolidophyceae sequences and (ii) to quantify the relative abundance of Bolidophyceae within the picoeukaryote community. Sequences available to date indicate that the class Bolidophyceae comprises at least three different clades, two corresponding to the previously described species Bolidomonas pacifica and Bolidomonas mediterranea and the third one corresponding to a subspecies of B. pacifica. Amplification of the SSU rRNA gene from natural samples with universal primers and hybridization using a Bolidomonas-specific probe followed by a eukaryote-specific probe allowed us to estimate the contribution of the Bolidophyceae to the eukaryotic DNA in both Pacific and Mediterranean waters to be lower than 1%. Similarly, high-performance liquid chromatography analyses of fucoxanthin, the major carotenoid present in Bolidophyceae, indicated that less than 4% of the total chlorophyll a in the picoplanktonic fraction in the equatorial Pacific was due to Bolidophyceae. Consequently, although strains of Bolidophyceae have been isolated from samples collected at several stations, this new class seems to have been a minor component of the natural picoeukaryotic populations in the ecosystems investigated, at least during the periods sampled.
定鞭藻纲（不等鞭毛类）是一个新描述的微微型浮游藻类纲，是硅藻的姐妹类群。通过培养分离、分子生物学技术和色素分析，对赤道太平洋和地中海地区定鞭藻纲的多样性和丰度进行了评估。从不同的中营养和贫营养区域分离出了8株定鞭藻纲菌株。相应的小亚基（SSU）rRNA基因序列使我们能够设计出两种针对定鞭藻纲的特异性探针。这些探针已用于天然样品中：（i）选择性扩增和检测定鞭藻纲序列；（ii）定量定鞭藻纲在微微型真核生物群落中的相对丰度。迄今为止可获得的序列表明，定鞭藻纲至少包括三个不同的进化枝，两个对应于先前描述的太平洋定鞭金藻和地中海定鞭金藻物种，第三个对应于太平洋定鞭金藻的一个亚种。使用通用引物从天然样品中扩增SSU rRNA基因，并先用定鞭金藻特异性探针杂交，然后用真核生物特异性探针杂交，这使我们能够估计定鞭藻纲在太平洋和地中海海域的真核生物DNA中所占比例低于1%。同样，对定鞭藻纲中主要类胡萝卜素岩藻黄质的高效液相色谱分析表明，赤道太平洋微微型浮游生物部分中总叶绿素a的不到4%归因于定鞭藻纲。因此，尽管已从多个站点采集的样品中分离出定鞭藻纲菌株，但至少在所采样的时期内，这个新纲似乎一直是所研究生态系统中天然微微型真核生物种群的次要组成部分。
