The dynamic switching of the bacterial flagellar motor regulates cell motility in bacterial chemotaxis. It has been reported under physiological conditions that the switching bias of the flagellar motor undergoes large temporal fluctuations, which reflects noise propagating in the chemotactic signaling network. On the other hand, nongenetic heterogeneity is also observed in flagellar motor switching, as a large group of switching motors show different switching bias and frequency under the same physiological condition. In this work, we present simultaneous measurement of groups of Escherichia coli flagellar motor switching and compare them to long time recording of single switching motors. Consistent with previous studies, we observed temporal fluctuations in switching bias in long time recording experiments. However, the variability in switching bias at the populational level showed much higher volatility than its temporal fluctuation. These results suggested stable individuality in E. coli motor switching. We speculate that uneven expression of key regulatory proteins with amplification by the ultrasensitive response of the motor can account for the observed populational heterogeneity and temporal fluctuations.
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http://dx.doi.org/10.1016/j.bpj.2013.09.043 | DOI Listing |
Biochemistry
January 2025
Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Third Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India.
Bacterial flagella are complex molecular motors that are essential for locomotion and host colonization. They consist of 30 different proteins expressed in varying stoichiometries. Their assembly and function are governed by a hierarchical transcriptional regulatory network with multiple checkpoints primarily regulated by sigma factors.
View Article and Find Full Text PDFInt J Food Microbiol
January 2025
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address:
Proc Natl Acad Sci U S A
January 2025
Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China.
Rotation of the bacterial flagellum, the first identified biological rotary machine, is driven by its stator units. Knowledge gained about the function of stator units has increasingly led to studies of rotary complexes in different cellular pathways. Here, we report that a tetrameric PilZ family protein, FlgX, is a structural component underneath the stator units in the flagellar motor of .
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan.
Many bacteria swim in liquid or swarm on surface using the flagellum rotated by a motor driven by specific ion flow. The motor consists of the rotor and stator, and the stator converts the energy of ion flow to mechanical rotation. However, the ion pathway and the mechanism of stator rotation coupled with specific ion flow are still obscure.
View Article and Find Full Text PDFPLoS Pathog
January 2025
Department of Microbiology, University of Georgia, Athens, Georgia, United States of America.
The Helicobacter pylori flagellar motor contains several accessory structures that are not found in the archetypal Escherichia coli and Salmonella enterica motors. H. pylori hp0838 encodes a previously uncharacterized lipoprotein and is in an operon with flgP, which encodes a motor accessory protein.
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