Multicellular magnetotactic prokaryotes (MMPs) exhibit peculiar coordination of swimming along geomagnetic field lines. Approximately 40–80 cells assemble, with a helical geometry or axisymmetry, into spherical or ellipsoidal MMPs respectively. To contribute to a comprehensive understanding of bacterial multicellularity here we took multiple microscopic approaches to study the diversity, assembly, reproduction and motility of ellipsoidal MMPs. Using correlative fluorescence in situ hybridization and scanning electron microscopy analysis, we found an unexpected diversity in populations of ellipsoidal MMPs in the Mediterranean Sea. The high‐pressure freezing/freeze substitution fixation technique allowed us to show, for the first time, that cells adhere via juxtaposed membranes and are held together by a rimming lattice. Fluorescence confocal microscopy and ultrathin section images revealed not only the one‐layer hollow three‐dimensional architecture, but also periphery–core unilateral constriction of constituent cells and unidirectional binary fission of the ellipsoidal MMPs. This finding suggests the evolution toward MMPs multicellularity via the mechanism of incomplete separation of offspring. Remarkably, thousands of flagellar at the periphery surface of cells underpin the coordinated swimming of MMPs in response to mechanical, chemical, magnetic and optical stimuli, including a magnetotactic photokinesis behaviour. Together these results unveil the unique structure and function property of ellipsoidal MMPs.

中文翻译：

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并列的膜支持细胞粘附并显示多细胞趋磁原核生物的单侧细胞分裂

多细胞趋磁原核生物（MMPs）沿地磁场线表现出独特的游动性。大约40–80个具有螺旋几何形状或轴对称性的细胞分别组装成球形或椭圆形MMP。为了有助于对细菌多细胞性的全面理解，我们在此采取了多种显微镜方法来研究椭圆形MMP的多样性，组装，繁殖和运动性。原位使用相关荧光杂交和扫描电子显微镜分析，我们发现了地中海椭圆形MMP种群中出乎意料的多样性。高压冷冻/冷冻替代固定技术使我们首次展示了细胞通过并列的膜粘附并通过边缘晶格保持在一起。荧光共聚焦显微镜和超薄切片图像不仅显示了一层空心的三维结构，而且还显示了组成细胞的外围核单侧收缩和椭圆形MMP的单向二元裂变。该发现表明通过后代不完全分离的机制向MMPs多细胞进化。值得注意的是 细胞外围表面成千上万的鞭毛支持MMP响应机械，化学，磁性和光学刺激（包括趋磁光动力学行为）而协调游泳。这些结果共同揭示了椭圆形MMP的独特结构和功能特性。