Ultrastructure of ellipsoidal magnetotactic multicellular prokaryotes depicts their complex assemblage and cellular polarity in the context of magnetotaxis
Ultrastructure of ellipsoidal magnetotactic multicellular prokaryotes depicts their complex assemblage and cellular polarity in the context of magnetotaxis
复制标题
椭圆体趋磁多细胞原核生物的超微结构描绘了它们在趋磁性背景下的复杂组合和细胞极性
DOI：
10.1111/1462-2920.13677
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发表时间：
2017-06-01
影响因子：
5.1
通讯作者：
Lins, Ulysses
中科院分区：
文献类型：
--
作者：
Leao, Pedro;Chen, Yi-Ran;Lins, Ulysses
趋磁性多细胞原核生物(MMPs)是由基因上相同的革兰氏阴性细菌组成的独特微生物组成的，这些细菌作为单个个体生活，能够产生被称为磁小体的磁性纳米颗粒。已知的MMPs有两种不同的形态：球形MMPs(SMMPs)和椭圆形MMPs(EMMPs)。SMMPs已被广泛研究，但有关eMMPs的信息较少。在这里，我们报道了磁铁矿磁小体生产者eMMPCandidatus Magnetananas rongchenensis的超微结构和组织以及与磁小体和鞭毛生物合成有关的基因簇。透射电子显微镜和聚焦离子束扫描电子显微镜(FIB-SEM)的三维重建显示，细胞以中心空间为中心排列，具有明显的核心-外围极性。磁小体被组织成沿每个细胞外围排列的多个链。在部分测序的基因组中，鉴定出与磁铁矿相关的maMAB基因和MAD基因簇。观察到两种细胞形态：不规则椭圆形、锥形和H形细胞。IECF细胞融合形成H型细胞，表明eMMPs的结构更加复杂，与考虑多细胞特性的sMMPs相比，eMMPs可能具有明显的进化地位。
Magnetotactic multicellular prokaryotes (MMPs) consist of unique microorganisms formed by genetically identical Gram-negative bacterial that live as a single individual capable of producing magnetic nanoparticles called magnetosomes. Two distinct morphotypes of MMPs are known: spherical MMPs (sMMPs) and ellipsoidal MMPs (eMMPs). sMMPs have been extensively characterized, but less information exists for eMMPs. Here, we report the ultrastructure and organization as well as gene clusters responsible for magnetosome and flagella biosynthesis in the magnetite magnetosome producer eMMP Candidatus Magnetananas rongchenensis. Transmission electron microscopy and focused ion beam scanning electron microscopy (FIB-SEM) 3D reconstruction reveal that cells with a conspicuous core-periphery polarity were organized around a central space. Magnetosomes were organized in multiple chains aligned along the periphery of each cell. In the partially sequenced genome, magnetite-related mamAB gene and mad gene clusters were identified. Two cell morphologies were detected: irregular elliptical conical ` frustum-like' (IECF) cells and H-shaped cells. IECF cells merge to form H-shaped cells indicating a more complex structure and possibly a distinct evolutionary position of eMMPs when compared with sMMPs considering multicellularity.