Journal
JOURNAL OF BACTERIOLOGY
Volume 192, Issue 15, Pages 4012-4021Publisher
AMER SOC MICROBIOLOGY
DOI: 10.1128/JB.00197-10
Keywords
-
Categories
Funding
- National Institute of Allergy and Infectious Diseases [AI057472]
Ask authors/readers for more resources
Bacillus cereus spores are assembled with a series of concentric layers that protect them from a wide range of environmental stresses. The outermost layer, or exosporium, is a bag-like structure that interacts with the environment and is composed of more than 20 proteins and glycoproteins. Here, we identified a new spore protein, ExsM, from a beta-mercaptoethanol extract of B. cereus ATCC 4342 spores. Subcellular localization of an ExsM-green fluorescent protein (GFP) protein revealed a dynamic pattern of fluorescence that follows the site of formation of the exosporium around the forespore. Under scanning electron microscopy, exsM null mutant spores were smaller and rounder than wild-type spores, which had an extended exosporium (spore length for the wt, 2.40 +/- 0.56 mu m, versus that for the exsM mutant, 1.66 +/- 0.38 mu m [P < 0.001]). Thin-section electron microscopy revealed that exsM mutant spores were encased by a double-layer exosporium, both layers of which were composed of a basal layer and a hair-like nap. Mutant exsM spores were more resistant to lysozyme treatment and germinated with higher efficiency than wild-type spores, and they had a delay in outgrowth. Insertional mutagenesis of exsM in Bacillus anthracis Delta Sterne resulted in a partial second exosporium and in smaller spores. In all, these findings suggest that ExsM plays a critical role in the formation of the exosporium.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available