title: Length-dependent flagellar growth ofVibrio alginolyticusrevealed by real time fluorescent imaging.
abstract: Bacterial ﬂagella are extracellular ﬁlaments that drive swimming in bacteria. During motor assembly, ﬂagellins are transported unfolded through the central channel in the ﬂagellum to the growing tip. Here, we applied in vivo ﬂuorescent imaging to monitor in real time theVibrio alginolyticuspolar ﬂagella growth. The ﬂagellar growth rate is found to be highly length-dependent. Initially, the ﬂagellum grows at a constant rate (50 nm/min) when shorter than 1500 nm. The growth rate decays sharply when the ﬂagellum grows longer, which decreases to ~9 nm/min at 7500 nm. We modeled ﬂagellin transport inside the channel as a one-dimensional diffusive process with an injection force at its base. When the ﬂagellum is short, its growth rate is determined by the loading speed at the base. Only when the ﬂagellum grows longer does diffusion of ﬂagellin become the rate-limiting step, dramatically reducing the growth rate. Our results shed new light on the dynamic building process of this complex extracellular structure.
authors.affiliation: Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan.
authors.forename: Meiting
authors.initials: M
authors.lastname: Chen
authors.affiliation: Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China.
authors.forename: Ziyi
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Yang
authors.affiliation: Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Peng
authors.affiliation: EMBL Australia Node for Single Molecule Science, University of New South Wales, Sydney, Australia.
authors.forename: Matthew Ab
authors.initials: MA
authors.lastname: Baker
authors.affiliation: Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Bai
authors.affiliation: Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan.
authors.forename: Chien-Jung
authors.identifier: 0000-0002-8078-4970
authors.initials: CJ
authors.lastname: Lo
mesh_terms: D005407:Flagella / Q000502:physiology*; D005408:Flagellin / Q000378:metabolism; D000069416:Intravital Microscopy; D007700:Kinetics; D061848:Optical Imaging; D001678:Organelle Biogenesis; D021381:Protein Transport; D044149:Vibrio alginolyticus / Q000502:physiology*
chemical_list: D005408:Flagellin
keywords: Vibrio alginolyticus; bacterial flagellar growth; biophysics; fluorescent imaging; infectious disease; injection-diffusion; microbiology; protein translocation; self-assembly; structural biology