L7- Microbiota - Pathogen Flashcards

1
Q

What is colonisation resistance

A

Protection from pathogens by microbiota

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2
Q

What dorts of yhings occur causing epi damage when less microbiota

A

Low iga, less tight junctions, less mucins

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3
Q

Give an examplr where microbiota consumption of polsyaccharides starves pathogens cia nutrient depletion

A

B theta consuming polysaccharides causes citrobacter rodentium to be starved = excluded from gut

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4
Q

Scfa have effects doscussed by smith and chen, what effect do they have on salmonella

A

Butyrate downregulates pi expression meaning less colonisation

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5
Q

How do scfa block ehec enterohaemorrhagic ecoli

A

Have bacteriocidal effects

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6
Q

What are the antimicrobial proteins secreted by microbiota called

A

Bacteriocins

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7
Q

Which bacteroides can target clostridia spre forming species like c difficule via bscteriocins

A

Bacteroides thuringiensis via thuricin cd bacteriocin

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8
Q

Which bacteriocin released from ecoli can block growth of other ecoli strains like ehec

A

Colicin

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9
Q

How many gene clusters possible for bacteriocin production

A

600

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10
Q

What do microbiota do to bile acids grom liver

A

Modify them to be bacteriocidal

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11
Q

What was found to colonise in reduced modified bile acids

A

C. difficile

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12
Q

How does indole release from microbiota work

A

Blocks virulence of pathogens and makes things less invasive to eg epi cells

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13
Q

How do indoles work with scfa

A

To block salmonella colonisation and entry via repressing SPI1 gene

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14
Q

Which other pathogen is reduced in attchment via indoles

A

Ehec

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15
Q

Which article talks about increase in amps via bacteria / microbiota

A

Ostaff 2013

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16
Q

What did ostaff 2013 say

A

Degranulation of paneth cells which release amps amongst lectin etc. this is cia tlr9 stimulation. Gives protection to pathognes like salmonella typhui

17
Q

What did sekirov 2010 say about scfa and amps

A

Increase in LL 37 cathelicidin via scfa which is downregulated in colitis

18
Q

Whoch article didcusses immune system evolution with microbiota

19
Q

What does peptidoglycan wall help do in ikmune system according to lee 2010

A

Induce neutrophil cytotoxicity

20
Q

What did gf micr have less off lee 2010

A

Iecs expressing mhc and tlrs

Also il 17 levels

21
Q

Which bacteria restores th17 in lamina propria

22
Q

What in sfb allows th17 differentiation

A

Serum amyloid A (lee 2010)

23
Q

How do scfa affect mucin layer

A

Increase expression of mucin 2

24
Q

What maintains integrity of tight junction

A

Microbiota

25
Which bacteroides induce t regs and also cd4 lymphocyte increase
B fragilis (tlr 2 for t regs)
26
How do microbiota have negative impact on colonisation resistance
Increase virulence through various metabolites
27
What does b theta cleave from mucin to increase c difficule colonisation
Sialic acid forming succinate
28
Which parts of the mucus barrier do microbiota utlise to increase ehec/epec vitulence
Succinate and fucose
29
What do fucose and shccinate allow in ehec and epec
Upregulate LEE (locus of enterocyte effacement) which is their pathogenicity island
30
Which pathogen requires modufied bule acids to germinate from spores
C difficile
31
What nitrogen source for salmonella can microbiota profuce alleoing the growth of salmonella
Ethanolamine
32
What effect does ethanolamine have on ehec
Regulates the virulence genes (increase)
33
Other than using metabolites from microbiota, how do pathogens overcome colonisation resistance
Use alternate nutrients like ethanolamine Inducing inflammstion Toxin production against commensals eg bacteriocins
34
How does succinate release by b theta cause mucin degradation
Activates epression of mucinase by ehec for better invasion
35
What does succinate from b theta release upregulate
T3ss in pathogens for colonisation
36
Which 2 pthogens are increasrd during antibiotics
Salmonella typhi and C. difficile
37
Which toxins do c difficile produce whicubcauses epithelial damage and colitis
TcdA and tcdB
38
What do antibiotics increase whcih is used as an alternate carbon source by salmonella and c difficle
Soalic acid converting to succinate