Flagella
Flagella - Related Videos
01:18
Flagella and Motility in Bacteria
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2025
Flagella are specialized, thread-like structures that extend from a bacteria's cell envelope. They play a crucial role in motility and chemotaxis. Their structural organization and functioning exemplify sophisticated biological engineering, enabling bacterial survival and adaptability in diverse environments.Structure of the FlagellumA bacterial flagellum consists of three key components: the filament, the hook, and basal body. The filament, a long, helical structure composed of repeating...
07:59
Investigating Flagella-Driven Motility in Escherichia coli by Applying Three Established Techniques in a Series
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Cited by 17 •
2020
Many bacteria use flagella-driven motility to navigate their environment and colonize favorable surroundings both individually and as a collective. Demonstrated here is the use of three established methods that exploit motility as a selection tool to identify components/pathways contributing to swimming and swarming motility.
02:09
Visualization of Bacterial Motility Using Redox Dye–Supplemented Semisolid Medium
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2025
Source: Chu, W., and Zhuang, X. Visualizing Bacterial Motility Based on a Color Reaction. J. Vis. Exp. (2022)This video demonstrates a redox dye-based semisolid agar assay for assessing bacterial motility by visually distinguishing motile and non-motile strains.
11:26
Visualizing Single Molecular Complexes In Vivo Using Advanced Fluorescence Microscopy
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Cited by 8 •
2009
Here we demonstrate the protocols for performing single-molecule fluorescence microscopy on living bacterial cells to enable functional molecular complexes to be detected, tracked and quantified.
09:47
Microdissection of Black Widow Spider Silk-producing Glands
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Cited by 18 •
2011
Here we describe an efficient strategy to remove the silk-producing glands from the abdomen of female black widow spiders. This procedure allows the rapid isolation of the seven distinct silk-producing glands in a highly purified fashion, an important process for investigators studying spider silk production and fiber assembly.
FAQs
In bacteria, movement begins when ion flow across the membrane powers a motor embedded in that membrane. The motor drives the basal body, which transmits rotation through the hook to the filament. This arrangement converts a membrane-associated energy source into propeller-like motion, linking molecular transport across the membrane with whole-cell movement through a fluid environment.
The two major flagellar systems differ in the physical action that produces motion. A bacterial structure rotates, whereas a eukaryotic axoneme generates bending waves through coordinated microtubule sliding. This distinction connects different cellular architectures to the same broad outcome, controlled movement or fluid displacement, and provides a basis for comparing motility across biology.
Chemotaxis couples flagellar motility to environmental sensing. A bacterium can alter its movement so that it travels toward favorable conditions and away from harmful ones. The flagellum therefore does more than provide propulsion: its activity becomes part of a behavioral response that links external chemical conditions with directional changes in cell movement.
Flagellar assembly is a useful research focus because a functional motility system depends on the coordinated organization of several parts, including the basal body, hook, and filament in bacteria. Examining how these structures are assembled helps cell biologists connect cellular architecture with movement and clarify how construction of the system supports overall motility.
Observations of flagellar assembly, motility, and regulation can reveal how cells behave in changing environments. In microbiology and cell biology, these features connect cellular structures with movement, while infection research uses them to examine mechanisms associated with harmful interactions. Comparisons among flagellar systems can also provide information about evolutionary relationships.
In eukaryotic cells, flagellar activity has distinct organism-level consequences. In sperm, coordinated bending supports propulsion, while in tissues, flagellar motion can move fluid across cell surfaces. These examples show how the same underlying axonemal mechanism can serve both individual-cell movement and organized transport within a multicellular environment.
Comparing flagellar assembly, motility, and regulation across cells can help clarify evolutionary relationships. The value comes from examining how different cellular systems organize movement and control it, rather than treating motility as an isolated trait. Such comparisons place bacterial and eukaryotic examples within a broader cell-biology context and relate structure, function, and cellular history.