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Jason's GI Block > Microbiota 1 > Flashcards

Microbiota 1 Flashcards

(64 cards)

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1
Q

how many commensals in/on us?

A

1-2kg

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2
Q

microbiome provides us with extra source of?

A

genes

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3
Q

humans and microbiota are known as:

A

mutualists

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4
Q

how many bacteria in microbiota?

A

10^14

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5
Q

how many species of bacteria on us?

A

1000

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6
Q

majority of bacteria use oxygen?

A

99.9% are anaerobes

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7
Q

Gram what in
Throat and skin
Gut
Vaginal?

A

Throat/ skin: +ve

gut: -ve
vaginal: +ve

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8
Q

4 main bacteria phyla from most to least

A
  1. bacteroides
  2. firmicutes (clostridia, mollicutes)
  3. actinobacteria
  4. proteobacteria (E.coli)
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9
Q

each body site has low or high diversity of microbiota?

A

high

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10
Q

twins have the same microbiota?

A

share <50% of bacterial species

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11
Q

microbiota unstable in host?

A

stable but influenced by determinants

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12
Q

4 things microbiota contribute to:

A

metabolism (cellulose)
development
immunity
protection

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13
Q

6 factors that influence gut microbiota?

A 
mode of delivery
age (more diversity with age)
diet (breast milk)
antibiotics
genetics/environment (rural vs. city)
chronic inflammation
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14
Q

vaginal birth associated with rapid acquisition of?

A

Firmicutes Bifidobacteria

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15
Q

animal based diets do what to microbiota?

A

decrease plant metabolizing bacteria, more bile-tolerant bacteria

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16
Q

what does iron do to mice microbiota?

A

more bacteroides

less bifidobacteria

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17
Q

does microbiota of mice treated with amoxicillin/metronidazole and bismuth recover?

A

yes

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18
Q

which antibiotic do you not recover your diversity of microbiota?

A

vancomysin

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19
Q

microbiota provides how much calories?

A

10% of calories from plant CHO

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20
Q

microbiota in nutrition does 2 things to help us

A
  1. change our genes for CHO/lipid metabolism

2. maintain enterocyte differentiation/function

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21
Q

microbiota taxa varied by site, what remained stable?

A

metabolic pathways eg. 16S rRNA

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22
Q

what vitamins do microbiota make for us?

A

vitamin B12, K
biotin
folate

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23
Q

what happens to bile acid in the gut?

A

microbiota break it down to desoxycholic acid to reabsorb back into liver

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24
Q

what happens to amino acids in gut?

A

nitrogen recycling from lysine and threonine

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25
what does bacterial degradation of host glycans do?
elicits synthesis of new glycans by host
26
how does microbiota maintain enterocyte differentiation
from production of short chain fatty acids from fibre
27
is angiogenesis affected by microbiota?
yes
28
describe the metabolism path of dietary fibre:
broken into monosaccharides>fermented into SCFAs>absorbed by colon>reaches liver>substrates for gluconeogenesis/lipgenesis
29
how do the colonic epithelial cells get their energy?
from fermented and absorbed SCFAs
30
SCFAs do more than just be energy source, explain:
control colonic gene expression via HDAC inhibition and GPCR signal regulation
31
mucosal immune systemis closely associated with?
intestinal microbiota
32
what is MALT?
mucosa-associated lymphoid tissue
33
SI covers how many square metres? so what?
400m2, big antigenic challenge, which is why it has the largest collection of lymphoid tissue
34
2 big things the MALT must be able to do
protection from pathogens (IgA) | tolerance to normal microbiota/food
35
what is ILFs? where are they found?
isolated lymphoid follicles in large/small intestine
36
where are Peyers patches? what happens there?
small intestine | induction of T, B Cells
37
enterocytes secrete what cytokines?
TGF-B, chemokines, anti-microbial peptides
38
what is lactoferrin? where does it come from on the small intestine?
on villus from Goblet cells inhibits bacteria growth
39
Paneth cells do what?
secrete defensins
40
what immune cells are in the lamina propria of the small intestine?
Intraepithelial lymphocytes (IEL)
41
2 kinds of Intraepithelial lymphocytes in the villus?
nonconventional lymphocytes | innate lymphocytes
42
what two cells in the small intestine play a role in tolerance?
``` enterocytes IEL (intraepithelial lymphocytes) ```
43
3 innate defences of gut?
peristaltic (flushing) action acid mucous layer to hold commensals at 'arms length'
44
Describe the 3 innate defensive roles of enterocytes
1. barrier: integrity is critical tight junctions 2. antimicrobial factors 3. cytokines/chemokines
45
What is a mechanism for controlled antigen access?
M Cells/ dendritic cells
46
innate leucocytes include:
lymphocytes | macrophages
47
What are ILCs? what do they do?
innate lymphoid cells | secrete cytokines
48
what does IL-17, IL-22 do?
recruits and activates neutrophils
49
What does lymphoid tissue inducer cells do?
stim DC, T, B cells, PPs, ILFs
50
what cytokine does IELs secrete?
IL-22
51
what does IL-22 do?3 things
enhances antimicrobe defence epithelial repair barrier integrity
52
What are MAIT cells? what do they do?
mucosal associated invariant T cells | rapid response to bacterial antigen
53
what do invariant NKT cells do?
secrete pro-inflamm cytokines like IL-22
54
M cell stands for? where is it?
microfold cell | directly over the lymphoid aggregates (PPs, ILFs isolated lymphoid follicles)
55
villi on M cells?
Nope | folded luminal surface
56
M-cell secrete mucous? why?
does not | microbial access easier
57
DCs are located directly below the M-cell, how do they sample? 2 ways:
directly (tentacle into lumen) | indirectly (via goblet/M-cells
58
TGF-B stands for?
transforming growth factor
59
tell me what DCs do in: 1. steady state 2. inflamm state
1. induce Tregs/TGF-B | 2. induce Th1/Th17
60
DCs bias what immunoglobulin from B-cells?
Isotype switching to IgA
61
inducing mucosal addressin a4B7 on T/B cells does what?
1. allows to bind to MAdCAM1 on mucosal surfaces | 2. also gives chemokine receptors specific for lamina propria
62
a4B7 activated T/Bcells are found where?
distributed through all mucosal surfaces
63
IELs do what to enterocytes?
may eliminate damaged ones
64
what happens in MALT?
stimulation suppression of immune cells

Jason's GI Block (32 decks)

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