Gut Microbiota Flashcards
How many organisms do we contain in our body?
100 trillion organisms: mostly bacteria, archaea, eukaryota, (fungi, and protozoa)
Where is the highest concentration of organisms in our body?
colon because we have a low pH in the stomach
Where is the most of our gut bacteria from?
90% from the phyla Firmicutes and Bacteroidetes, other important phyla is Actinobacteria (Bifidobacterium), and Proteobacteria
Are mucosa-associatd bacteria different from luminal bacteria?
Yes
Why do we refer to the colon as a microbial organ?
it contains 150x more genes than the human genome - includes a complex collection of glysocide hydrolases and polysaccharide lyases that break down complex carb linkages into consumable oligosaccharides or monosaccharides
How many % bacteria are we?
90
Proteobacteria
some pathogens
What do bacterias do?
digest indigestable things
5 functions of gut microbiota
enhances energy extraction through fermentation - SCFA production
essental vit synthesis
regulates immune system development
xenobiotic elimination
maintains integrity and function of gastrointestinal barrier
Dysbiosis
altered gut microbiota - could be associated with many diseases/disorders
Obesity and related gut microbiota - 2
decreased in abundance of dominant bacterial phyla -
bifidobacterium, and faecalibacterium prausnitzii
decreased microbiome diversity - high specificity and sensitivity
If bacteria in our digestive system went into the bloodstream
it would be attacked
are we born with gut microbiota?
no, GI tract of a fetus is sterile
Colonization of the infant gut (4)
genotype
mode of delivery - vaginal they get the gut bacteria of mother - lactobacillus prevotella, c-section - staphyfococcus, corynebaterium, propionibacterium, higher susceptibility to certain pathogens (skin/operating room), higher risk of atopic (hypersensitivity) diseases
early life exposure to antibiotics - kills everything
feeding practices - breast fed - increases bifidobacteria, formula fed - increase diversity
microbiota fingerprint established by
age 3 - remains stable
microbiota biome in early childhood - 4
new strains less certain in origin outcompete old ones
rapid increase in diversity
early microbiota development - high instability
shifts in response to diet and illness
adult microbiota biome - 2
highly distinct, differentiated microbiota
continue to change but at a slower rate
elderly microbiota biome
different than young adults
germ free vs germ mice and the amount of food
germ free ate more food 30%
germ ate less but had 40% in body fat
5 strategies to manipulate gut microbiota
prebiotics probiotics synbiotics antibiotics microbiota transplant
prebiotics - 2
effects attribute to - 4
non-digestible food ingredient food for healthy organisms - stimulate growth and metabolic activity - does not benefit from probiotics
- stimulation of beneficial bacteria and SCFA production
- improved barrier function
- suppression of lipogenic enzymes - decreased synthesis of lipoproteins and triglycerides
stimulation of glucagon like peptide secretion
probiotics - what are they, how do they do it? 2 common species
live health promoting organisms - benefit from prebiotics
- directly interact with host cells/indirectly through effects on other bacterial species
bifidobacteria, lactobacillus
synbiotics
combination of a synergistic prebiotic and probiotic
antibiotic
agent to inhibit growth of bacteria
microbiota transplant
transplantation of fecal bacteria
common prebiotics - 3
inulin, fructo-oligosaccharides, galacto-oligosaccharides
potential prebiotics - 3, what kinda diet can you go on?
resistant starch, xylo-oligosaccharides, arabinoxylan-oligosaccharides, high fiber/microbiota-accessible carb diet
6 food examples of prebiotics
bulb of leeks, jerusalem artichokes, jicama, onions, cooked and cooled potatoes, garlic
2 bacterial groups affected by prebiotics
generally bifidobacterium and lactobacillus
other beneficial organisms that may be increased are akkermansia mucinphila and faecalibacterium prausnitzii
what feeds bifidobacterium?
fructose molecule links that we cant break