Ultrastructure of Selenidium pendula, the Type Species of Archigregarines, and Phylogenetic Relations to Other Marine Apicomplexa
Ultrastructure of Selenidium pendula, the Type Species of Archigregarines, and Phylogenetic Relations to Other Marine Apicomplexa
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DOI：
10.1016/j.protis.2016.06.001
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发表时间：
2016-08-01
期刊：
影响因子：
2.5
通讯作者：
Guillou, Laure
中科院分区：
文献类型：
--
作者：
Schrevel, Joseph;Valigurova, Andrea;Guillou, Laure
Archiggregarines 是顶复门中的一个早期分支谱系，是一种鲜为人知的无脊椎动物寄生虫。根据其系统发育地位，古蠕虫是了解自由生活的有鞭毛捕食者到顶复门中的强制性寄生虫之间发生的功能转变的重要谱系。在这项研究中，我们使用Archigregarines的模式种Selenidiidae Selenidium pendula Giard，1884提供了基于SSU rDNA序列的新的超微结构数据和系统发育。我们首次在超微结构水平上描述了合子和早期配子生殖，揭示了具有中心锥的特征性核增殖、隐有丝分裂、染色质丝状网络、囊壁分泌物和9+0鞭毛雄配子的轴丝。 S. pendula 属于单系谱系，其中包括其他几个相关物种，均感染多毛类植物（Spionidae、Sabellaridae、Sabellidae 和 Cirratulidae）。所有这些硒物种都表现出相似的生物学特征：具有质膜的细胞皮层 - 内膜复合体 - 膜下微管组，具有圆锥体的顶端复合体，大量的棒状体和微线体，具有大食物泡的分核细胞增多症，syzygy 和 younggamonts 期间的核增殖。另外两个关系较远的类硒谱系感染Terebellidae 和Sipunculida，这为Archigregarines 能够寄生广泛的海洋宿主提供了基础。 (C) 2016 爱思唯尔有限公司。版权所有。
Archigregarines, an early branching lineage within Apicomplexa, are a poorly-known group of invertebrate parasites. By their phylogenetic position, archigregarines are an important lineage to understand the functional transition that occurred between free-living flagellated predators to obligatory parasites in Apicomplexa. In this study, we provide new ultrastructural data and phylogenies based on SSU rDNA sequences using the type species of archigregarines, the Selenidiidae Selenidium pendula Giard, 1884. We describe for the first time the syzygy and early gamogony at the ultrastructural level, revealing a characteristic nuclear multiplication with centrocones, cryptomitosis, filamentous network of chromatin, a cyst wall secretion and a 9+0 flagellar axoneme of the male gamete. S. pendula belongs to a monophyletic lineage that includes several other related species, all infecting Sedentaria Polychaeta (Spionidae, Sabellaridae, Sabellidae and Cirratulidae). All of these Selenidium species exhibit similar biological characters: a cell cortex with the plasma membrane - inner membrane complex - subpellicular microtubule sets, an apical complex with the conoid, numerous rhoptries and micronemes, a myzocytosis with large food vacuoles, a nuclear multiplication during syzygy and younggamonts. Two other distantly related Selenidium-like lineages infect Terebellidae and Sipunculida, underlying the ability of archigregarines to parasite a wide range of marine hosts. (C) 2016 Elsevier GmbH. All rights reserved.