Document Detail


The Azospirillum brasilense Che1 chemotaxis pathway controls swimming velocity, which affects transient cell-to-cell clumping.
MedLine Citation:
PMID:  22522896     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The Che1 chemotaxis-like pathway of Azospirillum brasilense contributes to chemotaxis and aerotaxis, and it has also been found to contribute to regulating changes in cell surface adhesive properties that affect the propensity of cells to clump and to flocculate. The exact contribution of Che1 to the control of chemotaxis and flocculation in A. brasilense remains poorly understood. Here, we show that Che1 affects reversible cell-to-cell clumping, a cellular behavior in which motile cells transiently interact by adhering to one another at their nonflagellated poles before swimming apart. Clumping precedes and is required for flocculation, and both processes appear to be independently regulated. The phenotypes of a ΔaerC receptor mutant and of mutant strains lacking cheA1, cheY1, cheB1, or cheR1 (alone or in combination) or with che1 deleted show that Che1 directly mediates changes in the flagellar swimming velocity and that this behavior directly modulates the transient nature of clumping. Our results also suggest that an additional receptor(s) and signaling pathway(s) are implicated in mediating other Che1-independent changes in clumping identified in the present study. Transient clumping precedes the transition to stable clump formation, which involves the production of specific extracellular polysaccharides (EPS); however, production of these clumping-specific EPS is not directly controlled by Che1 activity. Che1-dependent clumping may antagonize motility and prevent chemotaxis, thereby maintaining cells in a metabolically favorable niche.
Authors:
Amber Bible; Matthew H Russell; Gladys Alexandre
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2012-04-20
Journal Detail:
Title:  Journal of bacteriology     Volume:  194     ISSN:  1098-5530     ISO Abbreviation:  J. Bacteriol.     Publication Date:  2012 Jul 
Date Detail:
Created Date:  2012-06-12     Completed Date:  2012-08-21     Revised Date:  2013-06-26    
Medline Journal Info:
Nlm Unique ID:  2985120R     Medline TA:  J Bacteriol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3343-55     Citation Subset:  IM    
Affiliation:
Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee, USA.
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MeSH Terms
Descriptor/Qualifier:
Azospirillum brasilense / genetics,  metabolism,  physiology*
Bacterial Adhesion / physiology*
Bacterial Proteins / genetics,  metabolism*
Cell Membrane / metabolism
Chemotaxis / physiology*
Gene Expression Regulation, Bacterial*
Mutation
Signal Transduction
Surface Properties
Chemical
Reg. No./Substance:
0/Bacterial Proteins
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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