Cells of most bacterial species are around 2 micrometers in length, with some of the largest specimens reaching 750 micrometers. Using fluorescence, x-ray, and electron microscopy in conjunction with genome sequencing, we characterized Candidatus ( Ca. ) Thiomargarita magnifica, a bacterium that has an average cell length greater than 9000 micrometers and is visible to the naked eye. These cells grow orders of magnitude over theoretical limits for bacterial cell size, display unprecedented polyploidy of more than half a million copies of a very large genome, and undergo a dimorphic life cycle with asymmetric segregation of chromosomes into daughter cells. These features, along with compartmentalization of genomic material and ribosomes in translationally active organelles bound by bioenergetic membranes, indicate gain of complexity in the Thiomargarita lineage and challenge traditional concepts of bacterial cells.

中文翻译：

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一种厘米长的细菌，其 DNA 包含在代谢活跃的膜结合细胞器中

大多数细菌物种的细胞长度约为 2 微米，其中一些最大的标本达到 750 微米。我们使用荧光、X 射线和电子显微镜与基因组测序相结合，表征了候选人(钙。) Thiomargarita magnifica，一种平均细胞长度大于 9000 微米且肉眼可见的细菌。这些细胞比细菌细胞大小的理论极限增长了几个数量级，显示出前所未有的多倍体，超过 50 万份非常大的基因组，并且经历了染色体不对称分离到子细胞中的二态生命周期。这些特征，连同基因组物质和核糖体在由生物能量膜结合的翻译活性细胞器中的区室化，表明基因组物质的复杂性增加。硫玛格丽塔谱系和挑战细菌细胞的传统概念。