POSTERS - BLAST X - University of Utah
POSTERS - BLAST X - University of Utah
POSTERS - BLAST X - University of Utah
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<strong>BLAST</strong> X Thurs. Evening Session<br />
FUNCTION OF MULTIPLE CHEMOTAXIS-LIKE PATHWAYS IN MEDIATING CHANGES IN<br />
MOTILITY PATTERNS AND CELLULAR MORPHOLOGY IN AZOSPIRILLUM BRASILENSE<br />
Amber N. Bible 1 , Zhihong Xie 1 , Matthew Russell 1 and Gladys Alexandre 1,2<br />
1 Department <strong>of</strong> Biochemistry, Cellular and Molecular Biology and 2 Department <strong>of</strong> Microbiology,<br />
The <strong>University</strong> <strong>of</strong> Tennessee, Knoxville, TN 37996<br />
Molecular details on bacterial chemotaxis have been derived from studies <strong>of</strong> model<br />
organisms such as Escherichia coli and Bacillus subtilis which genome encode for a single<br />
chemotaxis pathway that functions to modulate changes in motility patterns. Comparative<br />
genomics analysis indicates that the genome <strong>of</strong> many bacteria possess multiple chemotaxis-like<br />
(Che) pathways. A. brasilense is a plant-associated bacterium that can differentiate in at least<br />
four different cell types (swimmer, swarmer, aggregated and cyst cells). Transition from one cell<br />
type to the other depends on the environmental (especially nutritional) conditions. One <strong>of</strong> the 4<br />
Che-like pathways (Che1) encoded within the genome <strong>of</strong> the alphaproteobacterium A.<br />
brasilense was recently shown to regulate changes in motility patterns, cell-to-cell aggregation<br />
concomitant with changes in cell length (Bible et al., 2008). We will present evidence for the role<br />
<strong>of</strong> two Che pathways and several chemoreceptors in controlling the ability <strong>of</strong> cells to modulate<br />
multiple cellular responses, including cell length, that suggest that cross-regulation between<br />
parallel chemotaxis pathways may function to coordinate and integrate a set <strong>of</strong> cellular<br />
functions. Experimental evidence suggests that proteins that function in the<br />
methylation/demethylation <strong>of</strong> chemoreceptors may have a critical role in this cross-regulation.<br />
The implications in the lifestyle <strong>of</strong> this bacterium will also be discussed in lights <strong>of</strong> recent<br />
experimental evidence obtained.<br />
Bible, A. N., Stephens, B. B., Ortega, D. R., Xie, Z. and G. Alexandre (2008) Function <strong>of</strong> a<br />
chemotaxis-like signal transduction pathway in modulating motility, cell clumping, and cell length<br />
in the alphaproteobacterium Azospirillum brasilense. J Bacteriol 190: 6365-6375.<br />
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