Daniela Boassa, Jennifer Lee, Germán Enciso, Christopher Chander, Tracy Lou, Sean Pairawan, Melody Guo, Frederic Wan, Mark Ellisman, Christine Sütterlin, Ming Tan (2017) CIL:50054, Chlamydia trachomatis, Human HeLa. CIL. Dataset

Chlamydia trachomatis is the most common cause of bacterial sexually transmitted infection. It produces an unusual intracellular infection: within a membrane-bound compartment called the chlamydial inclusion, the elementary body (EB) converts into the larger, metabolically-active reticulate body (RB). This RB replicates and then converts into an EB, which is the infectious form. We used quantitative three-dimensional electron microscopy to show that C. trachomatis RBs divide by binary fission and undergo a six-fold reduction in size as the population expands. Conversion only occurs after at least six rounds of replication, and correlates with smaller RB size. These results suggest that RBs only convert into EBs below a size threshold, reached by repeatedly dividing before doubling in size. Our findings support a model in which RB size controls the timing of RB-to-EB conversion without the need for an external signal.

沙眼衣原体是细菌性性传播感染最常见的原因。它产生了一种独特的细胞内感染：在称为衣原体包涵体的膜包被室中，原体（EB）转化为较大、具有代谢活性的网状体（RB）。此RB进行复制并随后转化为EB，后者为感染形式。我们采用定量三维电子显微镜技术，展示了沙眼衣原体RB通过二分裂进行分裂，并且在种群扩大的过程中尺寸减小六倍。这种转化仅在至少六轮复制之后发生，并且与较小的RB尺寸相关。这些发现表明，RB仅在达到一个尺寸阈值以下时才转化为EB，该阈值是通过在体积加倍前反复分裂而实现的。我们的研究结果支持了一种模型，即RB的大小控制了RB向EB转化的时机，而不需要外部信号的介入。