Gut microbiome

Question 1

Which are the mouse models allowing the study of gut microbiome

Answer 1

• WT - natural flora
• Specific Pathogen Free (SPF)
• Conventionalized - feces from SPF and transplant them to germ-free
• Gnotobiotic - Specific bacterial populations that you know
• Monocolonized - mice with 1 species of bacteria
• Germ Free

Question 2

What functions do the gut bacteria have

Answer 2

• Gut motility and secretion of bile acids and enzymes
• Absorption of nutrients and fermentation
• Cell composition - which cells that should be present and their differentiation
• Increasing threshold for activation of the immune system, so that the IS doesn’t explode for nonsens bacterias/pathogen
• Gut microbiome is a metabolic organ, producing huge amount of metabolites
• Brain development - impact the BBB and its integrity, or increasing hunger so behavior changes. During birth it is essential for closing the BBB

Question 3

When do we get our microbiota

Answer 3

At birth from our mother

Question 4

What are the three enterotypes

Answer 4

Enterotype is a classification of the major concentration of one type of bacteria, determining their differences in metabolism regardless of host gender, age etc.

• Bacteroides - carbohydrate metabolizing enzymes
• Precotella - peptide metabolizing enzymes
• Ruminococcus - carbohydrates and peptide metabolizing enzymes

Question 5

What factors changes the microbiota

Answer 5

• Xenobiotics - By eating antibiotics
• Pregnancy - a change in the mid period of pregnancy to increase adiposity, immune retention and high levels of inflammation
• Diet - differs between plant or animal based diets, can change rapidly. also dependent on intervall of eating

Question 6

What is disruption of microbiome homeostasis

Answer 6

dysbiosis affect the whole gut homeostasis

Question 7

Why is a fiber rich diet good

Answer 7

A diet consisting of more fibers give rise to a by-product of fermentation –> SCFA = short chain fatty acids; like Butyrate and propionate. These contribute to the homeostasis in the gut regarding the inflammatory activity. Since, SCFA act on epithelial cells in the GI causing them to activate ILC3 cells to produce IL-22, IL-10 and also stimulate the Treg polarization. All in all resulting in the anti-inflammatory response and also increasing the fucosylation on epithelial cells, acting as a nutrient for good bacteria and restricting entry of bad bacteria