L4

Question 1

Co-aggregation

Answer 1

Bacteria colonies arent randomly arranged, they arrange based on certain needs

Question 2

Biofilm formation steps

Answer 2

Attachment
Colonization
Growth

Question 3

What must occur before attachment?

Answer 3

Clean surfaces must be conditioned with organic molecules

Question 4

Reversible vs irreversible adsorption

Answer 4

Can der waals forces, weak, nonspecific
Vs
Adhesion molecules, specific

Question 5

Structure of mature biofilm

Answer 5

Cooperative consortia
75-90% extracellular polymer
5-25% bacteria
Numerous mushroom shaped microcolonies
Fluid filled channels carry nutrients and molecules

Question 6

advantages of biofilm (to bacteria)

Answer 6

Resistant to antimicrobials
resistant to host defences
Resistant to mechanical removal
Pool resources to digest nutrients (some utilize waste product of other species)

Question 7

Advantages of biofilm (to host)

Answer 7

presence of beneficial bacteria can prevent colonization
occupy space
stimulate immune system
produce molecules that kill other species

Question 8

Sessile bacteria

Answer 8

irreversible attachment phase

Question 9

Quorum sensing

Answer 9

micro colonies produce exopolymer and establish biofilm

Question 10

Light production in squid

Answer 10

Lux I: autoinducer synthase
LuxR: receptor and regulator: turns on expression of genes
Certain threshold of inducer is needed

Question 11

Oligopeptide mediated quorum sensing circuit

Answer 11

Transporter transports oligopeptide out of cell to bind to receptor (Gram +)

Question 12

Quorum sensing ways

Answer 12

LuxI/LuxR
Oligopeptide mediated
LuxS/AI-2

Question 13

LuxS/AI-2

Answer 13

LuxS makes signaling molecule AI-2
Gram + and -
Interspecies communicaiton

Question 14

Classes of signaling molecules

Answer 14

Acyl homoserine lactone (-)
Oligopeptides (+)
AI-2 (both)