Lecture 9

Question 1

P.aeruginosa is classified as a ___ pathogen.

Answer 1

Opportunistic

Question 2

P. aerugiosa is a opportunistic pathogen that leads to compromise of?

Answer 2

Immunocompromised patients, cancer and aids
Burn patients
Indwelling medical devices
Prolonged use of broad spectrum antibiotics

Question 3

There are two major quorum sensing system in P. Aeruginosa what are they?

Answer 3

Las System

rhl system

Question 4

What are the components of the las system?

Answer 4

• Autoinducer (AI)
• transcriptional activator: LasR
• Lasl (AI synthase)

Question 5

LasR-AI regulates?

Answer 5

Expression of number of virulence genes

Question 6

Once LasR-AI regulates number of virulence genes what are they?

Answer 6

LasB: etalase 
LasA: protease 
AprA: protease 
Tox A: exotoxins 
Last

Question 7

Name the autoinducers for the las system?

Answer 7

N-3-oxododeanoyl-homoserine lactone

3OC12-HSL

Question 8

Autoinducer of RHL system?

Answer 8

N-butyryl-homoserine lactone (C4-HSL)

Question 9

Components of rhl system

Answer 9

• (AI) N-butyryl- homoserine lactone (C4-HSL)
• AI synthase RhII
• transcriptional activator: RhIR

Question 10

RhlR-AI complex regulates?

Answer 10

Virulence gene

Question 11

What are the Virulence genes of RHL system?

Answer 11

• Rpos (RNA polymerase synthase)
• lasB (elastase)
• aprA (protease)
• rhamnolipid productions

Question 12

Both the las and Rhl system has shown high fidelity for their?

Answer 12

Regulatory components and gene targets

Question 13

Is there a link between las and Rhl system? if so explain how?

Answer 13

Yes there is a link between two systems. They are linked because the las system positively regulates expression of rhlR and Rhll.