Non‐uniform assembly of the Bacillus anthracis exosporium and a bottle cap model for spore germination and outgrowth
- 23 March 2007
- journal article
- Published by Wiley in Molecular Microbiology
- Vol. 64 (2), 359-367
- https://doi.org/10.1111/j.1365-2958.2007.05658.x
Abstract
Spores of Bacillus anthracis are enclosed by an exosporium composed of a basal layer and an external hair-like nap. The nap is formed by a collagen-like glycoprotein called BclA, while the basal layer contains many different proteins, one of which is a spore-specific alanine racemase (Alr). In this study, we employed fluorescence microscopy and a fluorescently labelled anti-Alr monoclonal antibody (mAb) to examine the distribution of Alr within the exosporium. Binding of the mAb occurred over approximately three-quarters of the exosporium but not in a cap-like region at one end of the spore, indicating the absence or inaccessibility of Alr in this region. We also determined that the cap-like region, or cap, corresponds to the first part of the exosporium assembled within the mother cell during sporulation and the only part of the exosporium assembled in a DeltaexsY mutant strain of B. anthracis. Our results provide the first direct evidence that exosporium assembly is a non-uniform process and suggest that exosporium formation is discontinuous. Finally, we demonstrated that during spore germination and outgrowth, the outgrowing cell always escapes from its exosporium shell by popping through the cap, suggesting that the cap is designed to facilitate the emergence of the outgrowing cell.Keywords
This publication has 54 references indexed in Scilit:
- Morphogenesis of the Bacillus anthracis SporeJournal of Bacteriology, 2007
- Fully Virulent Bacillus anthracis Does Not Require the Immunodominant Protein BclA for PathogenesisInfection and Immunity, 2007
- The ExsY Protein Is Required for Complete Formation of the Exosporium of Bacillus anthracisJournal of Bacteriology, 2006
- Importance of Nitric Oxide Synthase in the Control of Infection by Bacillus anthracisInfection and Immunity, 2006
- Compartmentalization of Gene Expression duringBacillus subtilisSpore FormationMicrobiology and Molecular Biology Reviews, 2004
- Surface Layer Protein EA1 Is Not a Component of Bacillus anthracis Spores but Is a Persistent Contaminant in Spore PreparationsJournal of Bacteriology, 2004
- Discovery of phage display peptide ligands for species-specific detection of Bacillus sporesJournal of Microbiological Methods, 2003
- AnthraxAnnual Review of Microbiology, 2001
- Monoclonal vs. heterogeneous anti‐H‐8 antibodies in the analysis of the anti‐phosphorylcholine response in BALB/c miceEuropean Journal of Immunology, 1981
- Identification of d-Alanine as the Auto-Inhibitor of Germination of Bacillus globigii SporesJournal of General Microbiology, 1964