This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Scharf, B. Search for Related Content PubMed PubMed Citation Articles by Scharf, B.

 Previous Article  |  Next Article 

Journal of Bacteriology, November 2002, p. 5979-5986, Vol. 184, No. 21
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.21.5979-5986.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Real-Time Imaging of Fluorescent Flagellar Filaments of Rhizobium lupini H13-3: Flagellar Rotation and pH-Induced Polymorphic Transitions

Lehrstuhl für Genetik, Universität Regensburg, D-93040 Regensburg, Germany

Received 14 June 2002/ Accepted 12 August 2002

The soil bacterium Rhizobium lupini H13-3 has complex right-handed flagellar filaments with unusual ridged, grooved surfaces. Clockwise (CW) rotation propels the cells forward, and course changes (tumbling) result from changes in filament speed instead of the more common change in direction of rotation. In view of these novelties, fluorescence labeling was used to analyze the behavior of single flagellar filaments during swimming and tumbling, leading to a model for directional changes in R. lupini. Also, flagellar filaments were investigated for helical conformational changes, which have not been previously shown for complex filaments. During full-speed CW rotation, the flagellar filaments form a propulsive bundle that pushes the cell on a straight path. Tumbling is caused by asynchronous deceleration and stops of individual filaments, resulting in dissociation of the propulsive bundle. R. lupini tumbles were not accompanied by helical conformational changes as are tumbles in other organisms including enteric bacteria. However, when pH was experimentally changed, four different polymorphic forms were observed. At a physiological pH of 7, normal flagellar helices were characterized by a pitch angle of 30°, a pitch of 1.36 µm, and a helical diameter of 0.50 µm. As pH increased from 9 to 11, the helices transformed from normal to semicoiled to straight. As pH decreased from 5 to 3, the helices transformed from normal to curly to straight. Transient conformational changes were also noted at high viscosity, suggesting that the R. lupini flagellar filament may adapt to high loads in viscous environments (soil) by assuming hydrodynamically favorable conformations.

This article has been cited by other articles:

• Meier, V. M., Muschler, P., Scharf, B. E. (2007). Functional Analysis of Nine Putative Chemoreceptor Proteins in Sinorhizobium meliloti. J. Bacteriol. 189: 1816-1826 [Abstract] [Full Text]  
• Nather, D. J., Rachel, R., Wanner, G., Wirth, R. (2006). Flagella of Pyrococcus furiosus: Multifunctional Organelles, Made for Swimming, Adhesion to Various Surfaces, and Cell-Cell Contacts.. J. Bacteriol. 188: 6915-6923 [Abstract] [Full Text]  
• Rotter, C., Muhlbacher, S., Salamon, D., Schmitt, R., Scharf, B. (2006). Rem, a New Transcriptional Activator of Motility and Chemotaxis in Sinorhizobium meliloti.. J. Bacteriol. 188: 6932-6942 [Abstract] [Full Text]  
• Eggenhofer, E., Rachel, R., Haslbeck, M., Scharf, B. (2006). MotD of Sinorhizobium meliloti and Related {alpha}-Proteobacteria Is the Flagellar-Hook-Length Regulator and Therefore Reassigned as FliK. J. Bacteriol. 188: 2144-2153 [Abstract] [Full Text]  
• Yao, S.-Y., Luo, L., Har, K. J., Becker, A., Ruberg, S., Yu, G.-Q., Zhu, J.-B., Cheng, H.-P. (2004). Sinorhizobium meliloti ExoR and ExoS Proteins Regulate both Succinoglycan and Flagellum Production. J. Bacteriol. 186: 6042-6049 [Abstract] [Full Text]  
• Trachtenberg, S., Fishelov, D., Ben-Artzi, M. (2003). Bacterial Flagellar Microhydrodynamics: Laminar Flow over Complex Flagellar Filaments, Analog Archimedean Screws and Cylinders, and Its Perturbations. Biophys. J 85: 1345-1357 [Abstract] [Full Text]