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Kinematics of intracellular chlamydiae provide evidence for contact-dependent development

David P Wilson1, Judith A Whittum-Hudson, Peter Timms

  • 1National 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.

Journal of Bacteriology
|June 23, 2009
PubMed

Insights

Chlamydia trachomatis differentiation from reticulate bodies (RB) to elementary bodies (EB) is triggered by detachment from the inclusion membrane. This movement change indicates the onset of RB to EB differentiation.

Area of Science:

  • Microbiology
  • Cell Biology
  • Infectious Diseases

Background:

  • Chlamydial development involves a complex differentiation process from replicative reticulate bodies (RB) to infectious elementary bodies (EB).
  • The precise trigger for RB to EB differentiation remains incompletely understood, with hypotheses suggesting various environmental or host-cell interactions.

Purpose of the Study:

  • To investigate the hypothesis that particle detachment from the chlamydial inclusion membrane (CIM) is a contact-dependent trigger for RB to EB differentiation.
  • To establish a relationship between the motility characteristics of Chlamydia trachomatis particles and their developmental stages.

Main Methods:

  • Live-imaging microscopy was used to track the temporospatial trajectories of individual Chlamydia trachomatis particles within infected McCoy cells.
  • Analysis of particle movement patterns, speed, size, and type was correlated with key developmental time points and antibiotic-induced stress conditions.

Main Results:

  • RB particles exhibited slight wobbling during early to mid-developmental stages, with increased average speed observed around 24 hours postinfection, coinciding with RB to EB differentiation.
  • Aberrantly enlarged, near-immobile particles in penicillin-supplemented cultures suggested continued tethering to the CIM.
  • A significant negative, nonlinear association was found between particle speed and particle size/type, supporting the hypothesis of detachment preceding differentiation.

Conclusions:

  • RB detachment from the CIM is coincident with the onset of late-stage RB to EB differentiation.
  • The study provides experimental evidence supporting a contact-dependent mechanism for chlamydial differentiation, linking particle motility to developmental transitions.

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