We previously isolated a symbiotic environmental amoeba, harboring an environmental chlamydia, Neochlamydia S13. Interestingly, this bacterium failed to survive outside of host cells and was immediately digested inside other amoebae, indicating bacterial distribution via cytokinesis. This may provide a model for understanding organelle development and chlamydial pathogenesis and evolution; therefore, we assessed our hypothesis of Neochlamydia S13 distribution via cytokinesis by comparative analysis with other environmental Chlamydiae (Protochlamydia R18 and Parachlamydia Bn₉). Dual staining with 4′,6‐diamidino‐2‐phenylindole and phalloidin revealed that the progeny of Neochlamydia S13 and Protochlamydia R18 existed in both daughter cells with a contractile ring on the verge of separation. However, in contrast to other environmental Chlamydiae, little Neochlamydia S13 16S ribosomal DNA was amplified from the culture supernatant. Interestingly, Neochlamydia S13 failed to infect aposymbiotic amoebae, indicating an intimate interaction with the host cells. Furthermore, its infectious rates in cultures expanded from a single amoeba were always maintained at 100%, indicating distribution via cytokinesis. We concluded that unlike other environmental Chlamydiae, Neochlamydia S13 has a unique ability to divide its progeny only via host amoebal cytokinesis. This may be a suitable model to elucidate the mechanism of cell organelle distribution and of chlamydial pathogenesis and evolution.

中文翻译：

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变形虫内共生环境衣原体Neochlamydia S13通过变形虫胞质分裂的分布

我们以前分离出一种共生的环境变形虫，窝藏环境衣原体，Neochlamydia S13。有趣的是，这种细菌无法在宿主细胞外存活，并立即在其他变形虫内被消化，表明细菌通过胞质分裂进行分布。这可能为理解细胞器发育和衣原体的发病机制和进化提供一个模型；因此，我们通过与其他环境衣原体（Protochlamydia R18 和Parachlamydia Bn ₉）的比较分析，评估了我们的新衣原体S13 通过胞质分裂分布的假设。4',6-二脒基-2-苯基吲哚和鬼笔环肽双重染色显示新衣原体的后代S13 和原衣原体R18 存在于两个子细胞中，在分离的边缘有一个收缩环。然而，与其他环境衣原体相比，从培养上清液中扩增出很少的新衣原体S13 16S 核糖体 DNA。有趣的是，新衣原体S13 未能感染无共生变形虫，表明与宿主细胞有密切的相互作用。此外，它在从单个变形虫扩展的培养物中的感染率始终保持在 100%，表明通过胞质分裂进行分布。我们得出的结论是，与其他环境衣原体不同，新衣原体S13 具有仅通过宿主变形虫胞质分裂分裂其后代的独特能力。这可能是阐明细胞器分布和衣原体发病机制和进化机制的合适模型。