Direct visualization of the outer membrane of mycobacteria and corynebacteria in their native state.

Zuber, Benoît; Chami, Mohamed; Houssin, Christine; Dubochet, Jacques; Griffiths, Gareth; Daffé, Mamadou (2008). Direct visualization of the outer membrane of mycobacteria and corynebacteria in their native state. Journal of bacteriology, 190(16), pp. 5672-5680. American Society for Microbiology 10.1128/JB.01919-07

[img] Text
J. Bacteriol.-2008-Zuber-5672-80.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (1MB) | Request a copy
[img] Image
figSuppl1.tif - Supplemental Material
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (2MB) | Request a copy

The cell envelope of mycobacteria, which include the causative agents of tuberculosis and leprosy, is crucial for their success as pathogens. Despite a continued strong emphasis on identifying the multiple chemical components of this envelope, it has proven difficult to combine its components into a comprehensive structural model, primarily because the available ultrastructural data rely on conventional electron microscopy embedding and sectioning, which are known to induce artifacts. The existence of an outer membrane bilayer has long been postulated but has never been directly observed by electron microscopy of ultrathin sections. Here we have used cryo-electron microscopy of vitreous sections (CEMOVIS) to perform a detailed ultrastructural analysis of three species belonging to the Corynebacterineae suborder, namely, Mycobacterium bovis BCG, Mycobacterium smegmatis, and Corynebacterium glutamicum, in their native state. We provide new information that accurately describes the different layers of the mycobacterial cell envelope and challenges current models of the organization of its components. We show a direct visualization of an outer membrane, analogous to that found in gram-negative bacteria, in the three bacterial species examined. Furthermore, we demonstrate that mycolic acids, the hallmark of mycobacteria and related genera, are essential for the formation of this outer membrane. In addition, a granular layer and a low-density zone typifying the periplasmic space of gram-positive bacteria are apparent in CEMOVIS images of mycobacteria and corynebacteria. Based on our observations, a model of the organization of the lipids in the outer membrane is proposed. The architecture we describe should serve as a reference for future studies to relate the structure of the mycobacterial cell envelope to its function.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy

UniBE Contributor:

Zuber, Benoît

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

0021-9193

Publisher:

American Society for Microbiology

Language:

English

Submitter:

Benoît Zuber

Date Deposited:

28 Jan 2016 15:00

Last Modified:

28 Jan 2016 15:00

Publisher DOI:

10.1128/JB.01919-07

PubMed ID:

18567661

BORIS DOI:

10.7892/boris.74802

URI:

https://boris.unibe.ch/id/eprint/74802

Actions (login required)

Edit item Edit item
Provide Feedback