Wilson David P, Whittum-Hudson Judith A, Timms Peter, Bavoil Patrik M
National Centre in HIV Epidemiology and Clinical Research, Faculty of Medicine, University of New South Wales, Level 2, 376 Victoria Street, Darlinghurst, Sydney, NSW 2010, Australia.
J Bacteriol. 2009 Sep;191(18):5734-42. doi: 10.1128/JB.00293-09. Epub 2009 Jun 19.
A crucial process of chlamydial development involves differentiation of the replicative reticulate body (RB) into the infectious elementary body (EB). We present experimental evidence to provide support for a contact-dependent hypothesis for explaining the trigger involved in differentiation. We recorded live-imaging of Chlamydia trachomatis-infected McCoy cells at key times during development and tracked the temporospatial trajectories of individual chlamydial particles. We found that movement of the particles is related to development. Early to mid-developmental stages involved slight wobbling of RBs. The average speed of particles increased sharply at 24 h postinfection (after the estimated onset of RB to EB differentiation). We also investigated a penicillin-supplemented culture containing EBs, RBs, and aberrantly enlarged, stressed chlamydiae. Near-immobile enlarged particles are consistent with their continued tethering to the chlamydial inclusion membrane (CIM). We found a significantly negative, nonlinear association between speed and size/type of particles, providing further support for the hypothesis that particles become untethered near the onset of RB to EB differentiation. This study establishes the relationship between the motion properties of the chlamydiae and developmental stages, whereby wobbling RBs gradually lose contact with the CIM, and RB detachment from the CIM is coincidental with the onset of late differentiation.
衣原体发育的一个关键过程涉及复制型网状体（RB）向感染性原体（EB）的分化。我们提供实验证据以支持一种接触依赖性假说，该假说用于解释分化过程中涉及的触发因素。我们在发育的关键时间点记录了沙眼衣原体感染的 McCoy 细胞的实时成像，并追踪了单个衣原体颗粒的时空轨迹。我们发现颗粒的运动与发育有关。发育的早期到中期阶段，RB 会有轻微摆动。感染后 24 小时（估计 RB 向 EB 分化开始后），颗粒的平均速度急剧增加。我们还研究了一种添加青霉素的培养物，其中含有 EB、RB 和异常增大、处于应激状态的衣原体。几乎不动的增大颗粒与它们持续附着在衣原体包涵体膜（CIM）上一致。我们发现颗粒的速度与大小/类型之间存在显著的负向非线性关联，这进一步支持了颗粒在 RB 向 EB 分化开始时脱离附着的假说。这项研究确立了衣原体运动特性与发育阶段之间的关系，即摆动的 RB 逐渐与 CIM 失去接触，并且 RB 从 CIM 脱离与晚期分化的开始同时发生。
