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Flashcards in Gut Microbiota Deck (77):
1

How many organisms do we contain in our body?

100 trillion organisms: mostly bacteria, archaea, eukaryota, (fungi, and protozoa)

2

Where is the highest concentration of organisms in our body?

colon because we have a low pH in the stomach

3

Where is the most of our gut bacteria from?

90% from the phyla Firmicutes and Bacteroidetes, other important phyla is Actinobacteria (Bifidobacterium), and Proteobacteria

4

Are mucosa-associatd bacteria different from luminal bacteria?

Yes

5

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

6

How many % bacteria are we?

90

7

Proteobacteria

some pathogens

8

What do bacterias do?

digest indigestable things

9

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

10

Dysbiosis

altered gut microbiota - could be associated with many diseases/disorders

11

Obesity and related gut microbiota - 2

decreased in abundance of dominant bacterial phyla -
bifidobacterium, and faecalibacterium prausnitzii
decreased microbiome diversity - high specificity and sensitivity

12

If bacteria in our digestive system went into the bloodstream

it would be attacked

13

are we born with gut microbiota?

no, GI tract of a fetus is sterile

14

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

15

microbiota fingerprint established by

age 3 - remains stable

16

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

17

adult microbiota biome - 2

highly distinct, differentiated microbiota
continue to change but at a slower rate

18

elderly microbiota biome

different than young adults

19

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

20

5 strategies to manipulate gut microbiota

prebiotics
probiotics
synbiotics
antibiotics
microbiota transplant

21

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

22

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

23

synbiotics

combination of a synergistic prebiotic and probiotic

24

antibiotic

agent to inhibit growth of bacteria

25

microbiota transplant

transplantation of fecal bacteria

26

common prebiotics - 3

inulin, fructo-oligosaccharides, galacto-oligosaccharides

27

potential prebiotics - 3, what kinda diet can you go on?

resistant starch, xylo-oligosaccharides, arabinoxylan-oligosaccharides, high fiber/microbiota-accessible carb diet

28

6 food examples of prebiotics

bulb of leeks, jerusalem artichokes, jicama, onions, cooked and cooled potatoes, garlic

29

2 bacterial groups affected by prebiotics

generally bifidobacterium and lactobacillus
other beneficial organisms that may be increased are akkermansia mucinphila and faecalibacterium prausnitzii

30

what feeds bifidobacterium?

fructose molecule links that we cant break

31

where do we get resistant starch? -2

cooked and cool potatoes, hard bananas

32

lean vs obese people microbes in germ free mice

obese would eat less and gain more weight

33

why are processed foods bad for your biome?

sugars that are absorbed and go right into your blood stream and starve your microbes

34

how can you tell if a food is high in fibre

things that get stuck in your teeth and are undigestible so lentils and leeks and bukwheat and quinoa

35

current diet and dietary fibre

huge drop

36

what nerve communicates between the digestive system and the base of the brain?

vagus

37

10 days of fast food and your microbe biome

6000 to 3500

38

how long did it take for the fast food guy to regain his biome diversity?

more than 2 weeks

39

antibiotics and biome

wipes out everything and the species go down in number, increasing the chances that they will be fat later

40

chances of being fat and c-section

22%

41

what other daily activities can increase your biome? -2

playing in dirt and with pets

42

bariatric surgery and biome

may be more than a new stomach

43

more ___ of food can increase your microbe biome

diversity

44

microbes can have widespread impact on?

diverse aspects of a host's physiology

45

Microbiata dysbiosis are starring in

growing list of western diseases such as metabolic syndrome

46

dysbiotic must be accompanied by

the recognition that the definition of a healthy microbiota that should serve a a frame of reference

47

MACs

microbiota accessible carbs - carbs metabolically available to gut microbes - dietary and resistant to degration and absorption by the host - may come from a variety of sources including plants

48

MACs for infants

breast milk known as human milk oligosaccharides

49

most common microbiota fuel for humans and it gives?

dietary plant/dietary fibre - carbs for gut microbrobe fermentation

50

What can the missing mechanistic explanation for the beneficial effects of dietary fibre be?

fermentation by the microbiota

51

Scenario for high MAC diet

few simple sugars, microbiota will create SCFA fermentation end products to create microbiota diversity and increase metabolic output - play diverse regulatory role including protection from many western disease

52

Scenario for low MAC diet

loss of beneficial microbial metabolites such as SCFA and weird microbiota, lower microbiota diversity and leads to western disease

53

gut microbiota of children from a rural village in Burkina Faso compared to "healthy" estern cohort in Italy - 3
what do they eat?

1. altered ration of 2 dominant phyla - increased rep of bacteroidetes relative to Firmicutes
2. increased microbiota diversity
3. large increases of SCFA production including 4-fold more butyrate and propinoate
twice the dietary fiber

54

microbiota from traditional agrarian gps compared to western counterparts

more similar to one another in microbiota diversity and SCFA production

55

link between microbiota diversity and health

unknown, but SCFA is likely a mediator - high MAC ->diversity-> fermentation end products in circulation (short chain FA, acetate, propionate, butyrate)

56

SCFAs are - 3

acetate, propionate, butyrate - energy source for the colonocytes absorbed by host - kcals salvaged/fermented from inaccessible carbs - also diverse regulatory role

57

dietary fiber and SCFA can

protect one from diet induced obesity

58

argument supporting why the ancient microbiota is better

traditional societies have mushc lower rates of western diseases

59

ability of microbiota to accommodate dietary change (MAC deprivation in generations of developed countries)

deleterious to its own maintenance and our health

60

metabolic syndrome often preceds

onset of T2D and CV diseases

61

main barrier between internal sites from luminal antigens is composed of

colonocytes and the seal between them provided by the tight junctions

62

Microbiota enhances 2

gut barrier function and protects against translocation of bacterial toxins by competition with potential pathogenic bacteria for nutrients

63

butyrate - 2

SCFA of particular interest for gut barrier function as it is a preferred nutrient for colonocytes - appears to enhance gut barrier function by regulation of TJ proteins and mucins.

64

prebiotic effect of a food component

stimulate growth of bifidobacteria and lactobacillus

65

saccharolytic

capable of hydrolyzing a sugar molecule - gut bacteria because humans eat carbs

66

Metabolic endotoxemia - what is it? mechanism?

endotoxins in blood - could be caused by high fat feeding - increased translocation of gram neg bacteria and bacteria derived components such as LPS into the bloodstream

67

intake of prebiotic fibres in combo with high fat diet

can counteract diet induced metabolic disturbances

68

microbiome in metabolically healthy ind appear to be - 3

enriched in bacterial gene functions, metabolism of co-factors and vitamins, and production of butyrate

69

using qPCR (real time polymerase chain reaction) to characterize the gut microbiota

identified increased abundance of bifidobacteria species in healthy vs obese and T2D

70

interventions with diff types of dietary fibre including prebiotics has shown to - 3

modulate gut microbiota and improve insulin sensitivity, low-grade chronic inflammation, and lipid metabolism

71

prebiotics create?
what does it help with?

SCFA
- acetate
- butyrane
- propiate
decrease pH

72

6 mechanisms of prebiotics

gut microbiota
- increased bifidobacterium, lactobacillus
- increase SCFA and decreases pH
improbed gut barrier
- increased GLP 2
Reduced inflammation
- decreased LPS
Reduced adiposity
- decrease lipogenesis
increased satiety
- increased GLP1/PYY
-decreased Ghrelin/energy dilution
Improved glycemia
- increased GLP 1 and decreased visceral adipose tissue

73

How specific are the beneficial effects of probiotics?

strain specific

74

5 probiotic mechanisms

gut microbiota
- increase strain of probiotic organism
- exclusion of pathogenic organisms
- reduced inflammation through probiotic interaction with immune cells
Improved gut barrier function
Reduced inflammation
- decreased LPS
Reduced adiposity
- decreased lipid uptake
improved blood lipids
- increased bile acid secretion
- decrease lipid uptake

75

extinct organisms in the gut

need to be reintroduced

76

PA and gut microbiota

increases diversity

77

Non-caloric artificial sweeteners and gut microbiota

increase insulin resistance