Bacterial Motility

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Bacterial Motility

• Hugh B. Fackrell

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Presentation Outline

• Bacterial Flagella
• Location
• Function
• Structure
• Bacterial vs eukaryotic flagella

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Flagellum vs Pilus
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Pilus (fimbriae)

• An appendage of the bacterial cell used for
  transfer of genetic information
• Plural pili

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Pili Transfer Plasmids
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Bacterial Flagellum

• A thin appendage arising from one or more
  locations on the surface of the cell wall
• Cellular locomotion
• Moves cell along gradients e.g. glucose

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Types of Motility

• Flagellated
• Flagellum-
• coordinated movement
• tumbling movement
• Axial filament- spirochetes
• Gliding- no visible organelles

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Location

• Polar
• Subpolar
• Lateral
• Lophotrichous
• Amphitrichous
• Peritrichous
• Periplasmic

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Polar Flagellum
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Lophotrichous Flagella
two or more flagella at the end of the
microbe Photographs show growth of flagella
during replication
Spirillum volutns
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Amphitrichous Flagella

• Tufts of flagella at BOTH ends of the microbe

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Peritrichous Flagella
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Flagellar tufts
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Flagellar tufts
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Spirochetes have Periplasmic Flagella

• Periplasmic flagella are also called the axial
  filament

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Axial filaments
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Bacterial Flagellum
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Rings of Gram Negative Flagellum

• M cell Membrane
• P Peptidoglycan
• L Outer Layer
• S Spacer

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Flagellar Structure (details)
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Prokaryotic Flagellum
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Flagellar Structures
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Assembly of Flagellum
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Demonstration of Chemotaxis

• Capillary tube contains attractant chemical
• Attractants
• Glucose,Maltose, Alanine
• Repellents
• Indole, H, OH-, fatty acids

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Flagellar Rotation

• Clockwise Tumbling
• Counterclockwise coordinated
• Alternate between two rotations

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Run Tumble motility
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Regulation of Flagellar Movement
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Movement of Flagella

• Whip
• Egg beater