Bacteria are nearly ubiquitous, play vital roles in industry and the environment, and are important actors in both health and disease for humans and other organisms. Given their importance, it is surprising how much we still don't understand about basic bacterial cell biology. We still don't know, for instance, how bacteria generate and maintain their characteristic shapes, establish polarity, organize their genomes, segregate their chromosomes, divide, and in some cases move. In eukaryotes, all these tasks are performed by cytoskeletal filaments, but because previous imaging technologies failed to reveal analogous structures in bacteria, it was long thought that bacteria don't possess cytoskeletons. More recently, fluorescence microscopy has shown that bacteria have substantial internal order. In the first cycle of this grant, we used another young technology, electron cryotomography (ECT), to produce three- dimensional images of intact bacterial cells in a near-native state to "molecular" (~4-6 nm) resolution. Using ECT we directly visualized hundreds of cytoskeletal filaments in ~20 different bacterial species, proving that the bacterial cytoskeleton is in fact both general and complex. Here we propose to develop and apply new correlated light and electron microscopy techniques to identify these filaments generally. This should allow us to resolve key discrepancies between the existing light and electron microscopical results and generate much-needed insight into the structures and functions of the bacterial cytoskeleton. We also propose work to improve EM image quality generally and expand the number of filaments being studied.

Public Health Relevance

Knowing the structure and function of the bacterial cytoskeleton will help us understand how bacteria accomplish their roles in health and disease and perhaps in the long-term future suggest new antibiotic targets.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM094800-08
Application #
8389595
Study Section
Microscopic Imaging Study Section (MI)
Program Officer
Deatherage, James F
Project Start
2005-12-15
Project End
2014-11-30
Budget Start
2012-12-01
Budget End
2013-11-30
Support Year
8
Fiscal Year
2013
Total Cost
$330,487
Indirect Cost
$122,317
Name
California Institute of Technology
Department
None
Type
Schools of Arts and Sciences
DUNS #
009584210
City
Pasadena
State
CA
Country
United States
Zip Code
91125
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Gan, Lu; Jensen, Grant J (2012) Electron tomography of cells. Q Rev Biophys 45:27-56
Tocheva, Elitza I; Matson, Eric G; Morris, Dylan M et al. (2011) Peptidoglycan remodeling and conversion of an inner membrane into an outer membrane during sporulation. Cell 146:799-812