Document Detail


Measuring the stiffness of bacterial cells from growth rates in hydrogels of tunable elasticity.
MedLine Citation:
PMID:  22548341     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Although bacterial cells are known to experience large forces from osmotic pressure differences and their local microenvironment, quantitative measurements of the mechanical properties of growing bacterial cells have been limited. We provide an experimental approach and theoretical framework for measuring the mechanical properties of live bacteria. We encapsulated bacteria in agarose with a user-defined stiffness, measured the growth rate of individual cells and fit data to a thin-shell mechanical model to extract the effective longitudinal Young's modulus of the cell envelope of Escherichia coli (50-150 MPa), Bacillus subtilis (100-200 MPa) and Pseudomonas aeruginosa (100-200 MPa). Our data provide estimates of cell wall stiffness similar to values obtained via the more labour-intensive technique of atomic force microscopy. To address physiological perturbations that produce changes in cellular mechanical properties, we tested the effect of A22-induced MreB depolymerization on the stiffness of E. coli. The effective longitudinal Young's modulus was not significantly affected by A22 treatment at short time scales, supporting a model in which the interactions between MreB and the cell wall persist on the same time scale as growth. Our technique therefore enables the rapid determination of how changes in genotype and biochemistry affect the mechanical properties of the bacterial envelope.
Authors:
Hannah H Tuson; George K Auer; Lars D Renner; Mariko Hasebe; Carolina Tropini; Max Salick; Wendy C Crone; Ajay Gopinathan; Kerwyn Casey Huang; Douglas B Weibel
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2012-05-02
Journal Detail:
Title:  Molecular microbiology     Volume:  84     ISSN:  1365-2958     ISO Abbreviation:  Mol. Microbiol.     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-05-23     Completed Date:  2012-09-17     Revised Date:  2014-03-19    
Medline Journal Info:
Nlm Unique ID:  8712028     Medline TA:  Mol Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  874-91     Citation Subset:  IM    
Copyright Information:
© 2012 Blackwell Publishing Ltd.
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MeSH Terms
Descriptor/Qualifier:
Bacillus subtilis / growth & development,  physiology*
Bacteriological Techniques / methods*
Biomechanical Phenomena
Culture Media / chemistry*
Elasticity*
Escherichia coli / growth & development,  physiology*
Hydrogels*
Models, Theoretical
Pseudomonas aeruginosa / growth & development,  physiology*
Grant Support
ID/Acronym/Agency:
5K25 GM075000/GM/NIGMS NIH HHS; DP2 OD008735/OD/NIH HHS; DP2 OD008735-01/OD/NIH HHS; DP2OD006466/OD/NIH HHS; DP2OD008735/OD/NIH HHS; T32 GM07215/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Culture Media; 0/Hydrogels
Comments/Corrections

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