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Gliding motility and polarized slime secretion.
1Departments of Biochemistry and of Developmental Biology, Stanford University School of Medicine Stanford, CA 94305, USA.
Molecular Microbiology
|December 21, 2006
Summary
Bacterial gliding motility relies on slime secretion. Disrupting slime secretion from one pole halts motility, while secretion from both poles prevents movement, revealing key genes for Myxococcus xanthus motility.
Area of Science:
- Microbiology
- Bacterial Motility
- Cellular Biology
Background:
- Myxococcus xanthus exhibits social gliding motility, essential for its life cycle.
- This motility involves the secretion of slime filaments, primarily observed at one cell pole.
- Understanding the genetic basis of this motility is crucial for deciphering bacterial movement mechanisms.
Purpose of the Study:
- To identify genes critical for Myxococcus xanthus adventurous (A) motility.
- To investigate the role of slime secretion polarity in regulating A motility.
- To elucidate the genetic control of slime production and its impact on bacterial swarming.
Main Methods:
- Generation and analysis of transposon insertion mutants with defective A motility.
- Phenotypic characterization of motility defects, including slime secretion patterns.
- Quantification of swarm expansion rates and elasticotaxis coefficients in mutant strains.
- Identification of mutated genes, particularly focusing on glycosyltransferase genes.
Main Results:
- Fifteen mutants completely lost A motility, exhibiting bipolar slime secretion, which prevents movement.
- Eighteen partial gliding (pgl) mutants showed reduced swarming rates, with secretion from a single pole.
- Swarm rate reduction in pgl mutants correlated with decreased elasticotaxis.
- Many pgl mutants resulted from insertions in glycosyltransferase genes, suggesting their role in slime synthesis.
Conclusions:
- Bipolar slime secretion is detrimental to Myxococcus xanthus A motility.
- Glycosyltransferases are likely involved in synthesizing the repeat unit polysaccharide of the slime.
- The regulation of slime secretion polarity and composition is fundamental for efficient bacterial gliding and swarming.
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