Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Infection and Immunology > Bacterial development > Flashcards

Bacterial development Flashcards

1
Q

Bacterial development

- alternative states

A

Spatial
= different parts of cell form different structures with different functions

Temporal
= alternative states as part of life cycle

Spatiotemporal
= combined

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Similarities and differences between stalk and swarmer cells

A

Same: Genome

Different: changes in gene expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Quorum sensing

- what is it?

A

Molecular system to monitor population density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Quorum sensing

- how does it generally work?

A

Bacteria secrete autoinducer molecules

  • low conc = doesn’t do much different
  • high conc = changes gene expression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Autoinducers

A

Peptide or small molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

2 proteins in the quorum-sensing system

A

LuxI
- synthesises autoinducers

LuxR
- transcriptional activator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Pseudomonas aeruginosa

- low vs high density

A

Low = harmless type
- inactive intracellular protein receptors

High = progressive type

  • active receptors
  • produces virulence factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

S.aureus

- low vs high density

A

Low
= adhesion phase

High
= invasion phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Steptomyces

- life cycle

A
  1. Spore germinates
  2. Vegetative mycelium
  3. Aerial hyphae
  4. Spore chains
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Development

- Diauxic shift

A

Bacteria grow on glucose until glucose exhausted

  • > changes in gene expression
  • > induces beta-galactosidase
  • > bacteria grow on lactose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Endospore formation

  • when does it occur?
  • what are they?
A

In response to stress conditions
- desiccation, starvation + cell density

= metabolically dormant cells
- resistant to heat, desiccation, toxins + radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Endospore formation

  • what do they enable?
  • when do they germinate?
A

Survival in adverse conditions + dispersal

When conditions are favourable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Control of entry into sporulation

A

Spo0A-P produced at 2 cons

Low = Vegetative growth continues + also produces toxins + proteases etc
Doing everything it can to survive

High = starts to sporulate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Sporulation

- genetics

A

~800 genes involved

Controlled by sigma factors
- controls whether genes are expressed within spore or mother cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Sporulation cycle

A
  1. Germination
  2. Vegetative state
  3. Starvation state
  4. Asymmetric cell division
  5. 1 copy of genome in spore and 1 in mother cell
  6. maturation state
  7. mother cell lyses
  8. mature spore germinates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Endospore structure

A

Exosporium
= thin proteinaceous layer
(some lipids + carbs)

Spore coat
= spore-specific proteins

Core wall
= normal peptidoglycan

Cortex
= unique form of peptidoglycan
= protective

17
Q

Endospore structure

- what happens in the centre of the spore (core/spore protoplasm)?

A

Centre of spore - pH drops by 1 unit
-> produce SASPs

SASPs
= small acid-soluble spore proteins
- protect DNA from damage
- Also C + energy source during germination

18
Q

Endospore germination

A

Activation
- germinate receptors sense a favourable enviro
(heat, rich nutrients, water)

Germination

  • endospore structures degraded
  • dipicolinic acid released

Outgrowth

  • swelling of core + expansion of cell
  • return to normal metabolic activity
19
Q

Endospore stability

A

Metabolically inactive + can survive without nutrients, water etc.

Survive extreme temps + harsh chemical treatments

Remain dormant for yrs

20
Q

Clostridium

- how it causes disease after antibiotics wipe out the microbiome

A
  1. Ingest clostridium spores
  2. Bile salts induce germination
  3. Adheres to cells
  4. Colonises cells + produces toxins
  5. Forms pseudomembrane
21
Q

Bascillus anthracis

- zebras

A
  1. Diseased zebra dies
  2. Spores stay in grass
  3. New zebra eats grass
  4. Zebra gets anthrax
22
Q

Biofilms

  • what are they?
  • why are they important to bacteria?
A

Microbial communities typically attached to a surface
(biotic or abiotic)

Pathogenesis

23
Q

Mixed biofilms

- features

A

Contain several different microbes

Occur naturally

Environmentally important

24
Q

Monoxenic biofilms

- features

A

Single microbial species

Artificial

Often associated with infections

25
Q

Biofilms

- e.g. Proteus mirabilis

A

UTI

Forms biofilms in urinary tract
- produces urinase crystals that block catheter

26
Q

Biofilm diversity

A

Differs between species:

> Matrix sugars + proteins
Signalling pathways
Physical forms

27
Q

5 stages of biofilm formation

A
  1. Attachment
  2. Aggregation
  3. Micro-colony formation
  4. Maturation
  5. Detachment
28
Q

Stages of biofilm formation

- 1. Attachment

A

Requires motility + surface attachment
> flagella
> pili (twitching)

29
Q

Stages of biofilm formation

- 4. Maturation

A

Further adaptation to life in a biofilm:
> metabolic rate/division slows down
> EPS/matrix production
> AB resistance

30
Q

Reasons for biofilms

- help promote growth + survival

A 
> trap + concentrate nutrients
> locate growth to favourable locations
> prevents detachment in flowing systems
> provide defence 
> allow community associations
31
Q

Biofilm resistance mechanisms

A

Antimicrobials can’t penetrate into biofilm

Decreased growth rate of cells in biofilm

Expression of resistance genes

Some cells survive AB
-> biofilm regrows
(= ‘persisters’)

32
Q

Reasons for biofilms

- allow community associations

A

Division of labour

- metabolic + genetic advantages

33
Q

Biofilms shaped by complex chemical gradients

A 
Copiotrophic biofilm 
- O2 gradient 
Aerobes at top 
-> Fermenters 
-> Anaerobes at bottom

Obligotrophic biofilm
- Nutrient gradient
Metabolically active cells at top
-> dead cells at bottom

pH gradient

Quorum sending gradient

34
Q

Biofilms shaped by complex metabolic networks

A

Chemical communication

Electrical communication

Cooperation
- Nitrification

Competition

  • ABs
  • cheating
  • nutrient depletion
35
Q

2 proteins in B.subtilis

A 
TasA = structural protein 
EPS = ECM
36
Q

Mutant with no EPS

Mutant with no tasA

A

No biofilm

No biofilm

37
Q

Combine EPS mutant + tasA mutant

A

Biofilm produced

38
Q

How to eradicate biofilms

A

Develop drugs or drug therapies to disable the persister phenotype
e.g. multi-drug therapy +/or cyclical applications

Incorporation of drugs unto surfaces
- prevent colonisation

Physical disruption
- ultrasound

Enhance detachment
- identify genes encoding biofilm destruction activities

Infection and Immunology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions