Flagella Flashcards

1
Q

5 types of motility

A
Swarming
Swimming 
Twitching 
Gliding 
Sliding
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2
Q
What structure does...require?
> swimming + swarming 
> twitching 
> gliding
> sliding
A

Flagella

Pilus retraction

Focal adhesion complexes

Spreading by growth

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3
Q

Fastest swimming bacteria

What happens when tase cells come together?

A

Thiovvulum majus

= 60 body lengths/sec

Form crystal-like, rotating lattice
= sucks in nearby bacteria

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4
Q

Put into order of length:
Fimbriae
Flagellum
Pili

(long -> short)

A

Flagellum

Pili

Fimbriae

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5
Q

4 locations of flagella

A

Polar = 1 end or both

Lophotrichous = lots on 1 end or both

Medial = 1 on the side

Peritirichous = many on the sides

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6
Q

Tumbling

A

Flagella turn clockwise

  • > try to change direction
  • > flagella splay = tumble
  • > flagella turn anti-clockwise
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7
Q

Energy source for powering flagella

A

Proton motive force

- flagella increase or decrease rotational speed in relation to strength of proton motive force

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8
Q

Flagella synthesis

A

50 genes required

  1. MS ring
  2. Other proteins + hook
  3. Filament grows from tip
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9
Q

Features of flagella

A

Basal body + rings
= anchor to envelope

Hook complex
= connects basal body to filament

Filament = propeller

Motor = drives flagella rotation

Secretion system = exports subunits

ATPase = energy source

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10
Q

Similarity of flagella with T3SS

A

Derived from common evolutionary ancestor + share 9 homologous constituents

Both arose from common primordial secretion system

Some components have been recruited by gene transfer

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11
Q

Evolutionary insights

- FlgK

A

= hook junction protein

  • internal repeats similar to auto transporter protein 7-60 amino acids
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12
Q

Evolutionary insights

- P-ring assembly chaperone

A

= FlgA

- similar to Pilus chaperones

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13
Q

Evolutionary insights

- FliJ

A

has amidase domain

- prepares cell wall for construction

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14
Q

Evolutionary insights

- FliA

A

= specific sigma factor controlling flagella genes

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15
Q

Regulation of flagella biosynthesis

- early genes

A

regulatory proteins that control expression of the regulation

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16
Q

Regulation of flagella biosynthesis

- middle genes

A

control expression of structural components

  • HBB complex, T3SS, regulatory genes for late gene expression
17
Q

Biosynthesis of flagella biosynthesis

- late genes

A

filament, motor force generators + chemosensory machinery

18
Q

Random walk

A

= alternating run and tumbles

e.g. down conc grads of toxins

19
Q

Taxis

A

= biased random walk

Bacteria move towards attractant by regulating switch between run + tumble

20
Q

Signalling + chemotaxis

- MCP

A

= Methyl-accepting chemotaxis proteins

- bind to specific attractants +/or repellents

21
Q

Process of signalling + chemotaxis

A

MCP assisted by CheW
=> stimulates auto-phosphorylation of CheA

CheA transfers P to CheY

CheY+P interacts with switch complex in flagella C ring

22
Q

How do attractants and repellents affect phosphorylation + run/tumble?

A

Attractants decrease phosphorylation
-> increases runs
= anti-clockwise

Repellents increase phosphorylation
-> increases tumbles
= clockwise

23
Q

MCPs in E.coli

A

MCP homodimers span membrane + sense signals in periplasm

Normally near 1 pole

Different MCPs sense different signals

24
Q

5 types of pili

A
Chaperone-Usher pili
Type IV pili
Type IV secretion pili 
Type V pili 
Curli fibres
25
Q

Roles of pili

A
Motility 
Conjugation 
Virulence
Biofilm formation 
Attachment
26
Q

Attachment

- adhesins

A

Chaperone-usher pili involved in attachment to host cells (Type I/ Type P pili)

Adhesins normally bind to specific molecules
-> specific attachment

27
Q

Pili essential for pathogenesis of UPEC

A

Type I/ Type P

28
Q

Twitching motility

A

Type IV pili

Elongation + retraction

ATP dependent

Exploration of surfaces

29
Q

Gliding motility

A

Flagella-independent motility

Slower + smoother than swimming

Requires surface contact

30
Q

Gliding motility

- mechanisms

A

Excretion of polysaccharide slime

Gliding-specific proteins