L8 - Microbiota And Pathogens

Question 1

Which microbiota via metagenomics of patients found to provide resistance to vibrio cholera

Answer 1

Ruminococcus obeum

Question 2

How

Answer 2

Using autoinducer 2 as a quorum sensor which reduces colonisation factors of vibrio

Question 3

What do bacteria regulste during quorum sensing

Answer 3

Gene expression

Question 4

What does population desnity habe to do with quorum signalling

Answer 4

Rleease of molecules like AI can increase to a certain conc when larger popn of bscteria. This readhes a threshold where they can turn on gene regulatory pathways eg to cause virulence

Question 5

AI1 is used by microbiota to try tsckle ehec. How does ehec avoid it

Answer 5

Senses ai1 via sdiA receptor and modulates it gene exp so it can survive in a new niche

Question 6

What article talks more about quorum snesing

Answer 6

Miller 2001

Question 7

What pathways of genes turned on due to wuorum snesing (miller 2001)

Answer 7

Motility, virulence, biofilm production, symbiosis

Question 8

Which types of bacteria use AI1 (miller 2001)

Answer 8

Gram +ve

Question 9

Whst do gram negstice use in quorum sensing as a moleculr (miller 2001)

Answer 9

Oligo peptides

Question 10

What type of secretort ststem does cholera have

Answer 10

T6ss

Question 11

What does t6ss do

Answer 11

Physicallt attack and kill commensals of cholera

Question 12

Which microbiota help reduce t6ss expression by cholera causing increase in commensals

Answer 12

Bifido bifidum

Question 13

How

Answer 13

Modify bilr acids into deoxycholic acid which downregulates t6ss

Question 14

How do microbiota actuvate nadr from the enteric nervous system

Answer 14

Deconjugate it from glucoronic acid by glucoronidase

Question 15

Which pathogens use nadr snesing to turn on virulence genes suppsoedly

Answer 15

Salmonella and ehec

Question 16

What sneses nadr in ehec particularly

Answer 16

Qsec histidine kinase

Question 17

What does qsec histidine kinase do with ehec

Answer 17

Increase exp of t3ss via Locus of enterocyte wffacement activation rcoding t3ss. Also other cirulence genes eg for shiga toxin

Question 18

What tpyes of a pathogen is salmonella

Answer 18

Facultstive ic parhogen (xan be both aerobic and anaerobic)

Question 19

What types of salmonella are there

Answer 19

Enterica from food

Typhi causinf typhoid fever

Question 20

How is typhi systemic

Answer 20

Allow escape via the mesentric lymph nodes

Question 21

Where do modt salmonella die

Answer 21

Stomach (unless turn on acid response systems)

Question 22

What expresses t3ss in salmonella

Answer 22

Spi1 and spi 2

Question 23

What is injected into epi crlls from t3ss which allows invagination of crll

Answer 23

Effector rpoteins which rearrange cytoskeleton

Question 24

What are aalmonella contained in within crlls

Answer 24

Salmonella containing vacuoles

Question 25

What does pi 19 encode

Answer 25

T6ss in s. Gallinerum (bird fever) and cholera

Question 26

What apecialised epi fells do salmonella prefer to enter cia t3ss

Answer 26

M cells

Question 27

Whats the difference between sp1 and sp2 t3ss

Answer 27

Spi1 allows entry into epi cells Spi2 allows survival in epi / macrophages within the scv

Question 28

What does nutrient availability depend on

Answer 28

Diet Microbiota composition

Question 29

How dors inflammation cause dysbiosis

Answer 29

Refuced obligate anaerobes ie commesals Increase in facultative anaerobes pathognes like ehec or salmoenlla

Question 30

Which cytokine is released in inflammation allowing fucose release ftom mucus carbs

Answer 30

Il 22

Question 31

What types of bscteria can utliise fucose as a nutrient

Answer 31

Ecoli

Question 32

What bacteria is a model for ehec and epec

Answer 32

Citrobacter rodentium

Question 33

Other than nutrients, what else does inflammation increase

Answer 33

Alternative electron acceptors in non anaerobic

Question 34

Which gene is activattd during inflammation with ifn y and other cytokines

Answer 34

Duox2- hydrogen peroxide production (a ROS)

Question 35

What thpes of diseases have increased duox2 from epi cells

Answer 35

Uc

Question 36

Ehat enzyme is upregulsted by nos2 due ti inflammatory cytokines

Answer 36

No synthetase

Question 37

How is no from nos involved in nitrate resp bu pathogens

Answer 37

Exposed to free radicals to produce peroxynitrate which can be concerted to nitrates

Question 38

How do ros and rns (no derived) speciies form nitrates in inflammation

Answer 38

They react together ans then allow nitrate resp from nitrate generation = growth of enterobacteria

Question 39

What does nitrate resp drive growth of as an alternative nutrient

Answer 39

Commensal and apthogenic ecoli aswell as salmonella. (NOT ANAEROBIC COMMENSALS)

Question 40

What are the 2 rypes of alternative electron acceptors in parhogens and commensal ecoli

Answer 40

Tetrathionate and nitrate

Question 41

Why is inflammation infuced by things like salmonella and ehec

Answer 41

Allows production of the AEA for alrernate food sources for growth

Question 42

How do pstjogens stimulate inflammation

Answer 42

Prr causing inflammatory cytokine release

Question 43

Which 3 things do the il22 and ifny etc increase

Answer 43

Lipocalin 2, ros and nos (aso fucose from il22)

Question 44

What does lipocalin 2 do to stop commensal eg commensal ecoli

Answer 44

Blocks fe acquisition which means they stop growing

Question 45

Which inflammatory cells increase ros production

Answer 45

Neutrophils

Question 46

What do ros from neutrophils do

Answer 46

Convert thiosulphate to tetrathionate which is used as an AEA for thiosulphatw resp eg salmonella

Question 47

What do microbiota release which is converted to thiosulfate allowing tetrathionate profuction

Answer 47

Hydrogen sulphate

Question 48

What nutrient is ysed as for carvon source by salmonella from epi cells

Answer 48

Ethanolamine due to its new AEA it allows salmoenlla to yse ethanolamine

Question 49

Why does ethanolsmine caused dysbiosis aswell as the nitrate/ tetrathionste AEA

Answer 49

Becaude microbiota cannot use them as a carbon source

Question 50

Which srticle talks about effector proteins from t3ss

Answer 50

Srikanth et al 2011

Question 51

Which protein in t3ss is responsible for inducing inflammation and also actin polymerisation + bundling for invaginstion

Answer 51

SipA