Benefits & Mischiefs from Normal Microbiota 2 Flashcards Preview

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Flashcards in Benefits & Mischiefs from Normal Microbiota 2 Deck (29):
1

Which PRRs are down regulated after birth?

TLR2 and TLR4 on the apical surface

2

Which PRRs are expressed in endosomes to target bacteria that end up within the cell?

TLR3, TLR7 and TLR9

3

Which PRR is expressed on the basolateral surface to target bacteria that cross the cell?

TLR5

4

What stimulates mucin production?

PAMPs on microbiota and butyrate produced by microbiota

5

What else does PAMP signalling of microbiota stimulate?

proliferation of crypt enterocytes and Paneth cells, release of antimicrobial peptides, induction of regulatory cytokines

6

How do short chain fatty acids stop inflammatory responses?

by inhibiting NF-kB and production of inflammatory cytokines

7

Which lymphoid structure develops postnatally?

isolated lymphoid follicles - due to signalling by microbiota

8

What is physiological inflammation?

inflammation induced by normal gut microbiota that lead to innate and adaptive defences and dont damage the host

9

What is pathological inflammation?

Inflammation in response to a pathogen

10

How do lymphoid tissues discriminate between microbiota and pathogens?

PRRs can detect number and proximity to epithelial surface, PRRs detect whether the bacteria has invaded the cell or not, microbiota only bind weakly to TLRs, only pathogens cause inflammasome signalling

11

Which antibody is produced by B cells in pathological inflammation?

IgG

12

What is the relationship between gut microbiota and the malnutrition disease kwashiorkor?

The microbiota in the children that get kwashiorkor is different to that of the healthy children - possibly due to the microbiota leading to inhibition of TCA cycle enzymes

13

What is the relationship between gut microbiota and obesity?

there is different microbiota in obese and non obese individuals where the obese have decreased diversity of microbiota - the decreased diversity leads to insulin resistance and increased serum triglycerides, cholesterol and insulin - there is also altered fermentation possibly leading to increased energy harvest

14

What is the relationship between gut microbiota and inflammatory bowel disease?

associated with an elevated immune response against gut microbiota and decreased diversity

15

What is a possible mechanism for inflammatory bowel disease?

defective signalling through PAMP-PRR with microbiota leading to chronic inflammation

16

What is the relationship between allergies and gut microbiota?

Early microbial colonisation is critical to protecting against allergies - pre and post natal microbial interactions are critical to develop a regulatory phenotype and antibiotics and cleanliness may interrupt this

17

Which gut microbiota can lead to urinary tract infections?

E coli

18

Which gut microbiota can lead to LRTI?

klebsiella

19

What are gut microbiota sometimes a source of for other bacteria?

DNA for virulence of antibiotic resistance

20

How can gut microbiota cause GIT disease?

By overgrowth e.g. candida causing diarrhoea or clostridium difficle causing pseudomembranous collitis

21

What type of bacteria is clostridium difficile?

gram positive, anerobic, spore forming rod

22

What causes overgrowth of clostridium difficile?

changes to gut microbiota e.g. by antibiotics or cytotoxic drugs

23

How does clostridium difficile cause pseudomembranous colitis?

It adheres to the mucosal epithelium and produces cytotoxic toxins that cause cell death, inflammation and bowel necrosis

24

What is the treatment for clostridium difficile?

metronidozole and vancomycin

25

Which patients have a greater incidence of recurrent clostridium difficile infections?

Patients who have had an appendectomy and who have reduced diversity of microbiota

26

What unusual treatment is very successful in treating clostridium difficile?

feacal transplants - to re establish normal microbiota

27

What are prebiotics?

dietary supplements that promote beneficial bacteria

28

What are probiotics?

a live organism that when ingested in adequate amounts exerts a health benefit on the host

29

Do prebiotics and probiotics help?

Unclear - difficult to find a high quality RCT on them