Ratio between external force flagella can withstand without breaking and the force produced by a swimming cell

Value >=100 Unitless
Organism Bacteria Salmonella enterica
Reference Darnton NC, Berg HC. Bacterial flagella are firmly anchored. J Bacteriol. 2008 Dec190(24):8223-4.PubMed ID18849436
Method The cell-bead mixture was placed on a microscope slide within a grease ring, covered with a no. 1 coverslip, and viewed with the optical trap used previously to measure filament force-extension curves (ref 4). The experiments were done at room temperature (~22°C).
Comments There are mutants of Salmonella enterica (with mutations in fliF and fliL) that shed flagella when they are swimming in a viscous medium or on the surface of soft agar. Filaments with hooks and the distal rod segment FlgG are recovered. We tried to extract flagellar filaments from such cells by pulling on them with an optical trap but failed, even when we used forces large enough to straighten the filaments. Thus, flagella are firmly anchored.
Entered by Uri M
ID 103814