Envelope Components of Gliding Bacteria

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Many bacteria are able to move over solid surfaces (often these are biological polymers such as agar, cellulose, chitin, pectin, or xylan) by a process termed gliding. This is an important aspect of these organisms' central role in the mineralization processes which so many "higher" forms of life are unable to effect, but upon which they are dependent. The mechanism by which the gliding bacteria accomplish this translocation remains a mystery; however, the sulfonolipids first isolated and described in this laboratory are the first molecules to be recognized as necessary (in the cytophagas an flexibacters) for gliding motility. A cell-surface polysaccharide also plays an accessory role. The current focus on the features of the cell envelope that are important in cell translocation will include a peptidoglycan-associated protein and other cell envelope features that change when a particular nongliding mutant regains, reversibly, the ability to glide. %%% The question of how gliding bacteria glide has been one of the most intractable problems in microbiology. There are no morphological clues to the mechanism of gliding. A number of laboratories have been working on the problem for many years, using both genetic and biochemical approaches, with minimal success. The Leadbetter laboratory made a breakthrough discovery when it was found that a particular nongliding mutant of Cytophaga johnsonae had a defect in the pathway of biosynthesis of a novel sulfonolipid, and that the nongliding phenotype could be reversed by the addition of the appropriate metabolic precursor (cysteate) to the culture medium. This project is a biochemical followup to that seminal discovery, and holds the promise of actually deciphering the nature of the bacterial molecule(s) involved in the gliding mechanism.