Gut Microbiota and Physiology Flashcards
How many cells are in the human body?
3 x 10^13
How many microorganisms are in the human body?
4 x 10^13
Considered to actually be an organ of the human body
Microbiome
The microbiome starts to develop DURING (not before)
Birth
What has the largest distribution of microbes in the GI tract?
Colon and then ileum
What are three examples of good bacteria in the gut?
Bifido bacteria, E. Coli, and Lactobacilli
Help to regulate levels of other bacteria in the gut
Bifido bacteria
Modulate immune responses to invading pathogens, prevents tumor formation, and produces vitamins
Bifido bacteria
Involved in the production of vitamin K2 (clotting) and help keep bad bacteria in check
E. Coli
Produces vitamins and nutrients, boosts immunity, and protects against carcinogens
Lactobacilli
What are three examples of bad microbes?
Campylobacter, Enterococcus Faecalis, Clostridium Difficile
The strains of campylobacter most commonly associated with human disease
C jejuni and C coli
Infection usually occurs through the ingestion of contaminated food
C jejuni and C coli infection
A common cause of post surgical infections
Enterococcus Faecalis
Most harmful following a course of antibiotics when it is able to proliferate
Clostridium Difficle
Of the 4 x 10^13 microorganisms in the adult human, what percentage is eukaryotes, archaeons, and viruses?
1%
How many species of bacteria are present in the mouth?
700 species
How many species of bacteria are in the colon?
800 species (7,000 strains)
What are the three types of host-microbial interaction
Commensalism, Mutualism, and Parasitism
When microbes benefit from the interaction, but the human hosts are not affected in any way
Commensalism
When the host and bacteria both benefit eachother, although the bacteria is not essential to the host
Mutualism
When microbes harm humans
Parasitism
Identification of all microbes by high-throughput DNA sequencing (instead of cultivation)
Metagenomics
Thicken GI muscle wall postnatally, improving motility
Gut microbiota
Stimulte GALT proliferation
Gut microbiota
Have overlapping and complementing functions in the gut
Commensal virus and bacteria
Increases nutrition efficiency
Gut microbiota
Gut microbiota can supply short chain fatty acids from otherwise undigestible
Polysaccharides
Gut microbiota supply essential amino acids and
Vitamin K
Aid in bile acid recycling in the colon, i.e. converting bile salts to bile acids
Gut microbiota
Gut microbiota alter the intrinsic metabolic machinery of host cells, resulting in more efficient nutrient uptake and
Utilization
The Centers for Disease Control and Prevention has identified a cluster of newborns in Tennessee with late
Vitamin K Deficiency Bleeding (VKDB)
A serious, but preventable bleeding disorder that can cause bleeding in the brain
VKDB
In each case, at birth the newborn’s parents declined
Vitamin K injection
In mice, increases glucose absorption, breakdown of triacylglycerols, intracellular trafficking of fatty acids, and export of triacylglycerols
B. Thetaiotaomicron
Increases Co-lipase and L-FAB activity
B. Thetaiotaomicron
Stimulates pancreatic lipase-related protein 2 activity
Co-lipase
Breaks down triacylglycerols
Pancreatic lipase-related protein 2
A reciprocal cause and effect
Dybiosis and metabolic syndrome
We can see the dysbiosis in type 2 DM patients via the decrease in
Butyrate-producing bacteria
Gnobiotic animals inoculated with obesity/type 2 DM-associated microbiota developed
Metabolic syndrome
Infants are more likely to develop obesity later in life if they are treated with
Antibiotics
Microbiota in kwashiorkor co-twins do not mature as microbiota in
Healthy co-twins
There was a severe weight loss shown in gnotobiotic mice inoculated with microbiota of
Kwashiorkor co-twins on malawian diet
This weight gain was not shown in the mice injected with microbiota of
Healthy co-twins
Gut microbiota function as part of a host’s innate
Defense system
Required for T-lymphocyte development
Pancreatic lipase-related protein 2
Normal microflora stimulate
GALT
Antibiotics can induce dysbiosis, i.e. diarrhea or colitis, which are caused by the otherwise commensal organism
Clostridium Difficile
Function as a helper to pathogens
Gut microbiota
Gut microbiota can promote enteric virus replication and systemic
Pathogenesis
Binds and stabilizes virions
Bacterial lipopolysaccharide (LPS)
LPS-bound virions bind viral receptors on host cells more
Efficiently
LPS-bound virus activating LPS-TLR4, leading to production of IL-6, which counters IL-10’s
Antiviral activity
We see better responses to cancer immunotherapy in patients with
Gut microbial diversity
Reduce therapeutic efficacies of cancer immunotherapy
Antibiotics
Produced by certain gut microbes from high-choline food
Trimethylamine (TMA) N-oxide
Reduces high-choline diet-induced plaque formation on vascular endothelium
A TMA N-oxide synthesis inhibitor
The inhibitor suppresses pro-atherosclerosis bacteria and enriches
Good bacteria formation
Are beneficial to pro-atherosclerosis bacteria such as clostridiales and ruminococcus
TMA and TMA N-oxide
Affect response to cancer immunotherapy (PD-1 therapy)
Gut microbes
Gut microbes increase nutrition efficiency. One major mechanism is through generating
SCFA from dietary fiber
Gut microbes are the major source of
Vitamin K
Critical for obesity, metabolic syndrome, and malnutrition
Dysbiosis
While the microbiota is an essential innate immune mechanism, it also facilitates certain
Viral infections
Affect response to cancer immunotherapies
Gut microbes
Targeting TMA synthesis and metabolism in bacteria may improve the health of the cardiovascular system by modifying
Cholesterol metabolism
