Morphology and molecular phylogeny of a marine interstitial tetraflagellate with putative endosymbionts: Auranticordis quadriverberis n. gen. et sp. (Cercozoa).
Morphology and molecular phylogeny of a marine interstitial tetraflagellate with putative endosymbionts: Auranticordis quadriverberis n. gen. et sp. (Cercozoa).
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DOI：
10.1186/1471-2180-8-123
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发表时间：
2008-07-22
期刊：
影响因子：
4.2
通讯作者：
Leander, Brian S.
中科院分区：
文献类型：
--
作者：
Chantangsi, Chitchai;Esson, Heather J.;Leander, Brian S.
比较形态学研究和环境测序调查表明，海洋底栖环境中含有各种各样的微生物，这些微生物刚刚开始被探索和鉴定。这些生境中最明显的捕食性鞭毛虫大小约为20-150 μm，属于三个主要的真核生物类群，彼此关系非常远：甲藻、裸藻和尾藻。尾虫是一个不同的组的变形虫鞭毛虫聚集在一起的分子遗传学推断主要是从核糖体基因序列。这些分子系统发育研究表明，一些神秘的类群，以前被视为真核生物insertae sedis，落在尾虫，并建议，这组的实际多样性在很大程度上是未知的。提高尾虫多样性的知识，预计将有助于解决真核生物树中的主要分支，并展示重要的细胞创新，了解真核生物的进化。一种罕见的四鞭毛藻，四河金藻。gen.et sp.，是从海砂样本中分离出来的未培养的细胞丰度低，并单独制备用于电子显微镜和DNA测序。这些鞭毛虫具有几个新的特征，如（1）四束回鞭毛的滑动运动，（2）直径约35-75 μm的心形细胞，（3）粘液体呈线状排列，呈明亮的橙子。每个细胞还具有2-30个淡橙子小体，直径一般为4-5 μm。由两层膜和囊状囊泡包裹。最内层的膜内陷，形成未堆叠的类囊体，并向含有尾病毒颗粒的中央蛋白核延伸。虽然据我们所知，这些机构从来没有在任何其他真核生物中描述，超微结构是最符合光合作用的蓝藻起源的内共生体。这种形态学特征的组合不允许我们将A.与任何已知的真核生物超群的同源性。因此，我们从两个不同的分离物的小亚基rDNA序列进行测序，并证明了这一谱系内的尾藻进化。我们发现并鉴定了A. quadriverfenum强调了我们对尾虫多样性的了解是多么的少，并且可能代表了尾虫内及以外的少数几个独立的初级内共生案例之一。
Comparative morphological studies and environmental sequencing surveys indicate that marine benthic environments contain a diverse assortment of microorganisms that are just beginning to be explored and characterized. The most conspicuous predatory flagellates in these habitats range from about 20–150 μm in size and fall into three major groups of eukaryotes that are very distantly related to one another: dinoflagellates, euglenids and cercozoans. The Cercozoa is a diverse group of amoeboflagellates that cluster together in molecular phylogenies inferred mainly from ribosomal gene sequences. These molecular phylogenetic studies have demonstrated that several enigmatic taxa, previously treated as Eukaryota insertae sedis, fall within the Cercozoa, and suggest that the actual diversity of this group is largely unknown. Improved knowledge of cercozoan diversity is expected to help resolve major branches in the tree of eukaryotes and demonstrate important cellular innovations for understanding eukaryote evolution. A rare tetraflagellate, Auranticordis quadriverberis n. gen. et sp., was isolated from marine sand samples. Uncultured cells were in low abundance and were individually prepared for electron microscopy and DNA sequencing. These flagellates possessed several novel features, such as (1) gliding motility associated with four bundled recurrent flagella, (2) heart-shaped cells about 35–75 μm in diam., and (3) bright orange coloration caused by linear arrays of muciferous bodies. Each cell also possessed about 2–30 pale orange bodies (usually 4–5 μm in diam.) that were enveloped by two membranes and sac-like vesicles. The innermost membrane invaginated to form unstacked thylakoids that extended towards a central pyrenoid containing tailed viral particles. Although to our knowledge, these bodies have never been described in any other eukaryote, the ultrastructure was most consistent with photosynthetic endosymbionts of cyanobacterial origin. This combination of morphological features did not allow us to assign A. quadriverberis to any known eukaryotic supergroup. Thus, we sequenced the small subunit rDNA sequence from two different isolates and demonstrated that this lineage evolved from within the Cercozoa. Our discovery and characterization of A. quadriverberis underscores how poorly we understand the diversity of cercozoans and, potentially, represents one of the few independent cases of primary endosymbiosis within the Cercozoa and beyond.
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蓝绿藻共生体的超微结构研究。
影响因子：
7.8
作者：
HALL, W T;CLAUS, G
通讯作者：
CLAUS, G
DOI：
10.1099/ijs.0.63229-0
发表时间：
2004-11-01
影响因子：
2.8
作者：
Bass, D;Cavalier-Smith, T
通讯作者：
Cavalier-Smith, T
影响因子：
5.4
作者：
Berney C;Fahrni J;Pawlowski J
通讯作者：
Pawlowski J
影响因子：
2.2
作者：
Atkins, MS;Teske, AP;Anderson, OR
通讯作者：
Anderson, OR
影响因子：
2.5
作者：
Bass, D;Moreira, D;Cavalier-Smith, T
通讯作者：
Cavalier-Smith, T