By Sachi Lagwankar

Quorum Sensing

• process of bacterial cells “talking” to each other in order to be informed of the population density in its vicinity• Bacteria can only act on the host cell when the impact of

the process is at its maximum

• Mutants (change signaling patterns) use QS in order to attack.

• used commonly when starting infections in organisms.

What is QS?

Oligopeptide signal

Gram positive bacteria

Pseudomonas quinolone signal (PQS; 2-heptyl-3-hydroxy-4-quinolone)

Gram negative bacteria

Autoinducers

• Chemical molecular signals• gram negative bacteria: acylated homoserine lactones

(AHL)• Gram positive bacteria: oligo-peptides

What are Autoinducers?

• only way mutants know how to communicate

• scientists are trying to find a way to inhibit this so that mutants don't take over host cells.

Importance

• sticky layer of polymers that microorganisms secrete and stick to one another on all surfaces

• Controlled by AI 2• Common in people,

though they can cause illness

Biofilm

• Multidrug-Resistant Tuberculosis (MDR TB) is resistant to the two most commonly used antibiotics for TB- isoniazid (INH) and rifampin (RIF). This means that people who get TB are unable to be cured using these antimicrobials. •  “tame” bacteria, and not to kill them

Antibiotics

Paul Williams: generate a drug that can

search and take out bacteria and that will

prevent them from doing damage to the host

cell.

Option 1

Geoff Watts: stop bacteria from sending

signals, eliminate infections

Option 2

Peter Greenberg: encourage mutants to dominate fatal wounds and they do better and do not use quorum sensing and are less virulent

Option 3

Steve Diggle: experiment- add mutants to the potential fatal wounds already infected with the virulent bacteria, those wounds actually did better.

Option 4

Alan Smyth: a natural quorum sensing inhibitor is

to use extracts of plants like garlic extract

Option 5

• the immune system take over the virus before it attacks the host cell and infects it.

• when mutants send signal, cell makes protein to be released out of cell

• confuse the mutant into thinking there are more of it. • when the mutant attacks, the human cell will use its

immune system to kill the mutant.

Design Goal

Design:

Truth Table

Pseudomonas aeruginosa

Using Design Illness

1 0 10 0 01 1 0

• idea of how quorum sensing can be used to prevent illness in humans.

• this is designed to help humans and prevent them from getting illnesses.

Ethics

• http://www.bbc.co.uk/programmes/p01bhlvr • http://rstb.royalsocietypublishing.org/content/362/1483/1241.full • http://downloads.bbc.co.uk/podcasts/worldservice/discovery/discovery_20130708-2000a.

mp3

• http://www.ncbi.nlm.nih.gov/pubmed/23142623 • https://www.youtube.com/watch?v=2R4XHRufoWI • http://jb.asm.org/content/187/13/4372 • http://en.wikipedia.org/wiki/Autoinducer • http://www.perspectivesinmedicine.net/content/2/11/a012427.full • http://www.ncbi.nlm.nih.gov/pubmed/11544353 • https://www.bio.cmu.edu/courses/03441/TermPapers/99TermPapers/Quorum/table.htm • http://www.ncbi.nlm.nih.gov/pubmed/11018124 • http://www.niaid.nih.gov/topics/tuberculosis/understanding/whatistb/pages/tbdefinitions.a

spx

• http://mpkb.org/home/pathogenesis/microbiota/biofilm

Sources