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