End Of L3 And L4 Flashcards
What is the dysbiosis seen in lung disorders
Asthma,copd and cf all have over powering levels of proteobacteria
How does scfa have to do with gut lung acis
Dampens downt he chances of chronic inflammation
What did huffnagle 2014 find on reducing allergies in lungs cia dietary fibre
Increased dietary fibre increased scfa which induced haemotapoesis of dc which arent able to predent and activate th2 responses
Who did an article on linking correlation yo causation via microbiome
Zhao 2013
What did zhao 2013 find
Using longitudinal or cross sextional studies and multisite sampling of gut microbiota for composition and functional analysis
Identify key microbiota via stats tools like principle component analysis
Isolate in culture or interventions to see if leceos of the microbiota impact on phenotypes
Identify if these attected metabolic,proteomic and transcriptomic patterns for cause
What type of microbiota seen in gut
Mostly bacterial
Why is there most in colon 10^11
Slower digestion and not acidic
How are bacteria for our health
The 5 main aspects highlighted in janeways
What happens if dysbiotic
They can cause diseases like ibd and chronic diseases
What are the largest phyla in gut
Bacteroidetes -ve and firmicutes +ve
Which types of bacteroidetes usually
Bacteroides
Why do we have larger metabolic potential with microbiota
They have 50-150 x more unique genes includint enzymatic genes for eg carb utilisatiom (GH, PL)
What is the firsr example where microbiota signal to host for a mutualist relationship
Bacteroides theta signals host whwn it needs fucose as a carbon htilisation (hooper et al 1999)
Explain hooper et al 1999 hypothesis
Bt uses a fucR repressor which binds to the fuc operon promoter which has enzyme genes for fucose metabolism eg L- fucose isomerase
When fucose is high, fucose can bind the fucR which removes it from operon. Sending signals for fucose metabolism
Another site was found called csp promoter. When this is expressed it sends signalling to host for more fucose.
In high fucose the fucR will bind and repress this so no signal to jost. When L - fucose is low can no longer suppress csp because L fucose is needed as a co repressor at this site with fucR. Therefore a aignal is sent to host for more fucose
Which enzyme does b theta have for fucose removal on terminal sugars for carbon source
A fucosidase
Example 2- scfa reudcing inflammation (smith et al 2013)
Scfa like butyrate and proprionate found to induce t regs by binding to the GPR43 on their surface.
This induced il 10 releasing foxp3 t regs.
Propionate increased proliferation of t regs by blocking hdac 6 and 9 which down regulate t regs
Found to reduce colitis symptoms
3rd example - distinguishing friend from foe (round et al 2011)
Bacteroides fragilis bind tlr 2 via polysaccharide A. This instead of inducing th17 upregulates t regs releasing il10. Also allows balance of th2 and th1 responses.
Also reduced il17 levels and t regs suppression of th17
Sxplain psa
Zwitteronic polysaccharide whoch is not seen on mant spexies, therefore producing a unique tlr2 response
How do t regs suppress th17 responses
Trduce production of il 6 needed for th17 differentiation (zhang 2007)
