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Chemotaxis in a gliding bacterium.

Authors
  • Kearns, D B
  • Shimkets, L J
Type
Published Article
Journal
Proceedings of the National Academy of Sciences
Publisher
Proceedings of the National Academy of Sciences
Publication Date
Sep 29, 1998
Volume
95
Issue
20
Pages
11957–11962
Identifiers
PMID: 9751772
Source
Medline
License
Unknown

Abstract

Myxococcus xanthus cells exhibit directed motility up phosphatidylethanolamine (PE) gradients, and we suggest that PE behaves as a chemoattractant. Computer-assisted stop-motion digital microscopy was used to record cell movements in slide culture. PE decreased cellular reversal frequency with molecular specificity that was correlated with the fatty acid composition. Synthetic dilauroyl (di C12:0) PE and dioleoyl (di C18:1 omega9c) PE suppressed direction reversals and stimulated movement up the gradient. Sensory adaptation occurred about 1 hr after the onset of stimulation. Null mutants in a methylated chemotaxis protein homolog (FrzCD) and a CheA/CheY homolog (FrzE) moved up a PE gradient at a reduced rate. The mutants displayed normal excitation but were defective in adaptation. A dominant, hyper-reversal mutant in the M. xanthus methyl accepting chemotaxis protein homolog, frzCD224, failed to respond to PE stimulation, which argued that PE was a transduced stimulus. Neither dilauroyl PE nor dioleoyl PE is present at high enough concentrations in vegetative or developmental PE to account for all of the chemotactic activity. It appears then that there are additional, as yet unknown, PE species that serve as autoattractants. We report on a discrete phospholipid chemoattractant in a gliding bacterium

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