Knowledge clips gut side 3

Question 1

The colon is anaerobic

Answer 1

true

Question 2

Butyrate is ..
How is it produced?

Answer 2

critical SCFA. Need 3 different types of bacteria to produce this. If you lose these bacteria, you lose a very important signal, you lose benefits.

Question 3

 How many different phyla are known so far and how many of them are frequently found in the human intestine? The ratio between known versus found phyla is

Answer 3

50:6

Question 4

 What is NOT a feature of the pathogenic bacteria living in our gut concerning drugs?

Answer 4

Convert pro-drugs to active metabolites

Question 5

 Traveling from America to Asia can cause a major switch in the gut microbiota, however, this effect is in general reversible when you are healthy
True/false

Answer 5

True

Question 6

NGS:

Answer 6

sequencing mutiple genomes at once

Question 7

SCFA: a microbiota-derived bioactive compound. What are its functions?

Answer 7

> energy source
activate enteroendocrine cells in intestinal wall
strengthen intestinal barrier (tight junction genes)
inhibit inflammation by stimulating excretion IL-10 and activating T-regs cells

Question 8

Bile acids: How much of the bile acids ends up in the colon and what happens with it then?

Answer 8

95% of primary bile is reabsorbed by jejunum and ileum
5% that enters colon is modified by microbes with enzymes expressed that contribute to formation of secondary bile acids

Question 9

What vitamins are most essential for bacterial metabolism?

Answer 9

K & B: most essential, for bacterial metabolism (synthesize B-vitamins or precursors: B6, B2, folate)

Question 10

Proteins: undergo fermentation, bioactive compounds can be divided into 5 groups:

Answer 10

1. Gases
2. SCFA and BCFA (branch-chained)
3. Nitrogen-containing
4. Amines
5. Microbe-associated molecular patterns (MAMPs): components derived from bacterial wall, recognized as endo-toxins

Question 11

Biogenic amines (dopamine, GABA, serotonin, histamine): all generated by commensal gut microbes via excreted hormone-like signals. Bidirectional communication between bacteria =

Answer 11

microbial endocrinology
-> Signal is also facilitating communication between micro-organisms and host.
(LTA’s in gram-negatives and LPS in gram-positives)

Question 12

 What is the current hypothesis about the number of microbiota-derived metabolites present in the colonic lumen of a healthy adult?

> 10
100
500
1000

Answer 12

> 1000

Question 13

 MAMPs are components of the bacterial wall
True/false

Answer 13

True

Question 14

 Histamine and serotonin are biogenic X that signal to the brain

Answer 14

amines

Question 15

 Vitamins synthesized by gut microbiota are ..

Answer 15

B-type vitamins and vitamin K

Question 16

 What is the ratio human versus bacterial genes in the human body?

Answer 16

1:100

Question 17

 Gases like H2, CO2, CH4 and H2S are produced during …

Answer 17

the fermentation of proteins

Question 18

What increases and decreases during ageing, concerning the gut microbiota? What shift happens?

Answer 18

Increase bacteroides during ageing, decrease variable/other (decrease diversity). Shift obligatory to facultative anaerobic bacteria (can live in presence/absence oxygen).

Question 19

Recall 5 helpers in intestinal immune responses:

Answer 19

• M-cells
• DC’s
• B & T lympho’s
• IgA
• AMP’s

Question 20

Some conditions might disturb immune homeostasis:

Answer 20

1. Dysbiosis
2. Increased permeabilit
   3 IBD
   4 Ageing

Question 21

Dysbiosis: characterized by…

Answer 21

increase in facultative anaerobes and more pathogenic bacteria.
 can result from a reduction in the mucus layer, bacteria can cross intestinal barrier and cause local inflammation

Question 22

2. Increased intestinal permeability (leaky gut), also has reduction of …
   Can be caused by….

Answer 22

mucus layer
Allows invasion of bacteria etc, can move to other parts of body.
 Can be caused by dysbiosis, medication, alcohol, exercise

Question 23

What are two processes that disturb immune homeostasis in the gut upon ageing?

Answer 23

inflamm-aging (chronic low-grade inflammation), immunosenescence (effectivity immune response is decreasing: decrease number + effectivity adaptive immune response)