Peritrichously-flagellated bacteria, such as Escherichia coli, self-propel in fluids by using specialised motors to rotate multiple helical filaments. The rotation of each motor is transmitted to a short flexible segment called the hook which in turn transmits it to a flagellar filament, enabling swimming of the whole cell. Since multiple motors are spatially distributed on the body of the organism, one would expect the propulsive forces from the filaments to push against each other leading to negligible swimming. We use a combination of computations and theory to show that the swimming of peritrichous bacteria is enabled by an elastohydrodynamic bending instability occurring for hooks more flexible than a critical threshold. Using past measurements of hook bending stiffness, we demonstrate how real bacteria are safely on the side of the instability that promotes systematic swimming.
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http://dx.doi.org/10.1038/s41598-018-28319-8 | DOI Listing |
Proc Natl Acad Sci U S A
October 2024
Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048.
J Bacteriol
October 2024
Biology Department, Siena College, Loudonville, New York, USA.
Motility allows microbes to explore and maximize success in their environment; however, many laboratory bacterial strains have a reduced or altered capacity for motility. Swimming motility in depends on peritrichous flagella and is carried out individually as cells move by biased random walks toward attractants. Previously, we adapted strain 3610 to the laboratory for 300 generations in lysogeny broth (LB) batch culture and isolated lab-adapted strains.
View Article and Find Full Text PDFPhys Rev E
June 2024
Department of Physics, Brown University, Providence, Rhode Island 02906, USA.
The recent discovery of the peritrichous, swarm-competent bacterium Enterobacter sp. SM3 has offered a new opportunity to investigate the connection between bacterial swimming and swarming. Here, we report the run-and-tumble behavior of SM3 as planktonic swimming cells and as swarming cells diluted in liquid medium, drawing comparison between the two states.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2023
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455.
To swim through a viscous fluid, a flagellated bacterium must overcome the fluid drag on its body by rotating a flagellum or a bundle of multiple flagella. Because the drag increases with the size of bacteria, it is expected theoretically that the swimming speed of a bacterium inversely correlates with its body length. Nevertheless, despite extensive research, the fundamental size-speed relation of flagellated bacteria remains unclear with different experiments reporting conflicting results.
View Article and Find Full Text PDFMar Life Sci Technol
November 2022
College of Fisheries/Shuangshui Shuanglü Institute, Huazhong Agricultural University, Wuhan, 430070 China.
The subclass Peritrichia, containing two orders Sessilida and Mobilida, is a major group of ciliates with worldwide distribution and high species diversity. Several studies have investigated the phylogeny of peritrichs; however, the evolutionary relationships and classification of some families and genera within the Sessilida remain unclear. In the present study, we isolated and identified 22 peritrich populations representing four families and six genera and obtained 64 rDNA sequences to perform phylogenetic analyses and assess their systematic relationships.
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