Vesicles

Question 1

Structure of OMVs

Answer 1

Membrane: Lipopolysaccharide, proteins, peptidoglycan
Contents: toxins, DNA, RNA and periplasmic proteins

Question 2

Blebbing

Answer 2

Turgor pressure built up in out membrane that causes bulging before releasing the vesicle

Question 3

Bacterial lysis

Answer 3

• explosive cell lysis
• caused by prophage
• religating forms vesicles

Question 4

Membrane remodelling and integrity

Answer 4

As they grow they want to adjust to their environment
Can change things by producing vesicles

Question 5

Tol-pal system

Answer 5

maintains membrane integrity
is a gene cluster
Tol-Pal cluster is comprised of:
- inner membrane proteins (TolA, TolQ, TolR),
- periplasmic protein (TolB) and
- an outer membrane peptidoglycan-associated protein (Pal)

Question 6

Membrane remodelling of LPS

Answer 6

Salmonella can alter the type of LPS on their surface
discovered by knocking ot PagL gene
- PagL is an enzyme that facilitates LPS remodelling and increases OMV production

Question 7

MVs

Answer 7

expression of endolysin from defective phage weakens peptidoglycan

○ causes a budging cytoplasmic membrane material through holes in the peptidoglycan, which are then released as explosive MVs

Question 8

What causes an upregulation of outer membrane blebbing

Answer 8

iron limitation
signalling molecules
hydrophobic compounds
antibiotics

Question 9

What causes an upregulation of explosive cell lysis

Answer 9

antibiotics
DNA-damaging agents
peptidoglycan degrading enzymes

Question 10

What causes an upregulation of bubbling cell death

Answer 10

antibiotics
DNA-damaging agents
peptidoglycan degrading enzymes

Question 11

OMVs cause NOD-1 signalling

Answer 11

NOD1 detects Gram negative peptidoglycan
delivery of peptidoglycan via vesicle
drives NFKB and inflammatory response

Question 12

What receptor and PAMP do I need to remember

Answer 12

LPS - TLR4
Lipoproteins - TLR2
Peptidoglycan - NOD1
CpG TLR9

Question 13

How do vesicle modulate immunity

Answer 13

delivers immunomodulatory sRNAs that decrease cytokine production

Question 14

Non-parthenogenic benefits

Answer 14

Acquire nutrients: siderophores that bind nutrients and then deliver the cargo back to the parent bacteria

Decoys to protect bacteria: e.g. bind to antibiotics to protect parent bacteria or to protect to a phage

Removes toxins or misfolded proteins

Degrade antibiotics and transfer resistance
- Package beta-lactamase or DNA for other cells

Energy sources from the environment