Architecture and host interface of environmental chlamydiae revealed by electron cryotomography

Author(s)
Martin Pilhofer, Karin Aistleitner, Mark S. Ladinsky, Lena König, Matthias Horn, Grant J. Jensen
Abstract

Chlamydiae comprise important pathogenic and symbiotic bacteria that alternate between morphologically and physiologically different life stages during their developmental cycle. Using electron cryotomography, we characterize the ultrastructure of the developmental stages of three environmental chlamydiae: Parachlamydia acanthamoebae, Protochlamydia amoebophila and Simkania negevensis. We show that chemical fixation and dehydration alter the cell shape of Parachlamydia and that the crescent body is not a developmental stage, but an artefact of conventional electron microscopy. We further reveal type III secretion systems of environmental chlamydiae at macromolecular resolution and find support for a chlamydial needle-tip protein. Imaging bacteria inside their host cells by cryotomography for the first time, we observe marked differences in inclusion morphology and development as well as host organelle recruitment between the three chlamydial organisms, with Simkania inclusions being tightly enveloped by the host endoplasmic reticulum. The study demonstrates the power of electron cryotomography to reveal structural details of bacteria-host interactions that are not accessible using traditional methods.

Organisation(s)
External organisation(s)
California Institute of Technology (Caltech)
Journal
Environmental Microbiology
Volume
16
Pages
417-429
No. of pages
13
ISSN
1462-2912
DOI
https://doi.org/10.1111/1462-2920.12299
Publication date
2014
Peer reviewed
Yes
Austrian Fields of Science 2012
106022 Microbiology
ASJC Scopus subject areas
Ecology, Evolution, Behavior and Systematics, Microbiology
Portal url
https://ucrisportal.univie.ac.at/en/publications/fd1f1334-f844-478c-a179-0a3997b08c3b