L7- Microbiota - Pathogen Flashcards
What is colonisation resistance
Protection from pathogens by microbiota
What dorts of yhings occur causing epi damage when less microbiota
Low iga, less tight junctions, less mucins
Give an examplr where microbiota consumption of polsyaccharides starves pathogens cia nutrient depletion
B theta consuming polysaccharides causes citrobacter rodentium to be starved = excluded from gut
Scfa have effects doscussed by smith and chen, what effect do they have on salmonella
Butyrate downregulates pi expression meaning less colonisation
How do scfa block ehec enterohaemorrhagic ecoli
Have bacteriocidal effects
What are the antimicrobial proteins secreted by microbiota called
Bacteriocins
Which bacteroides can target clostridia spre forming species like c difficule via bscteriocins
Bacteroides thuringiensis via thuricin cd bacteriocin
Which bacteriocin released from ecoli can block growth of other ecoli strains like ehec
Colicin
How many gene clusters possible for bacteriocin production
600
What do microbiota do to bile acids grom liver
Modify them to be bacteriocidal
What was found to colonise in reduced modified bile acids
C. difficile
How does indole release from microbiota work
Blocks virulence of pathogens and makes things less invasive to eg epi cells
How do indoles work with scfa
To block salmonella colonisation and entry via repressing SPI1 gene
Which other pathogen is reduced in attchment via indoles
Ehec
Which article talks about increase in amps via bacteria / microbiota
Ostaff 2013
What did ostaff 2013 say
Degranulation of paneth cells which release amps amongst lectin etc. this is cia tlr9 stimulation. Gives protection to pathognes like salmonella typhui
What did sekirov 2010 say about scfa and amps
Increase in LL 37 cathelicidin via scfa which is downregulated in colitis
Whoch article didcusses immune system evolution with microbiota
Lee 2010
What does peptidoglycan wall help do in ikmune system according to lee 2010
Induce neutrophil cytotoxicity
What did gf micr have less off lee 2010
Iecs expressing mhc and tlrs
Also il 17 levels
Which bacteria restores th17 in lamina propria
Sfb
What in sfb allows th17 differentiation
Serum amyloid A (lee 2010)
How do scfa affect mucin layer
Increase expression of mucin 2
What maintains integrity of tight junction
Microbiota
Which bacteroides induce t regs and also cd4 lymphocyte increase
B fragilis (tlr 2 for t regs)
How do microbiota have negative impact on colonisation resistance
Increase virulence through various metabolites
What does b theta cleave from mucin to increase c difficule colonisation
Sialic acid forming succinate
Which parts of the mucus barrier do microbiota utlise to increase ehec/epec vitulence
Succinate and fucose
What do fucose and shccinate allow in ehec and epec
Upregulate LEE (locus of enterocyte effacement) which is their pathogenicity island
Which pathogen requires modufied bule acids to germinate from spores
C difficile
What nitrogen source for salmonella can microbiota profuce alleoing the growth of salmonella
Ethanolamine
What effect does ethanolamine have on ehec
Regulates the virulence genes (increase)
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
How does succinate release by b theta cause mucin degradation
Activates epression of mucinase by ehec for better invasion
What does succinate from b theta release upregulate
T3ss in pathogens for colonisation
Which 2 pthogens are increasrd during antibiotics
Salmonella typhi and C. difficile
Which toxins do c difficile produce whicubcauses epithelial damage and colitis
TcdA and tcdB
What do antibiotics increase whcih is used as an alternate carbon source by salmonella and c difficle
Soalic acid converting to succinate
