Lecture 19 - Gut microbiome and ageing

Question 1

the majority of species in the gut microbiome belong to which 2 species of bacteria?

Answer 1

bacteriodetes and firmicutes

Question 2

how many genes make up the gut microbiome?

Answer 2

316 million

Question 3

name the 7 major functions of the gut microbiome

Answer 3

pathogen protection, synthesis of vitamins, immune system development, fat storage, SCFA production, modulation of CNS, intestinal angiogenesis

Question 4

name the 8 roles of SCFAs

Answer 4

provide energy for colonocytes and hepatocytes, contribute to intestinal barrier integrity, protect against inflammation, reduce risk of colorectal cancer, increase insulin secretion, help DNA homeostasis, regulate skeletal muscle metabolism, modulate CNS

Question 5

how do SCFAs in the gut contribute to intestinal barrier integrity in 2 ways?

Answer 5

upregulate expression of tight junction proteins and mucus production

Question 6

which cranial nerve carries signals between brain heart and gut?

Answer 6

vagus nerve (CNX)

Question 7

name 4 diseases linked to dysbiosis in the gut microbiome?

Answer 7

IBS, type 2 diabetes, obesity, cardiovascular diseases

Question 8

which chemical, which gets translocated to the immune system has hormones which affect memory function, reduce inflammation and reduce ageing/permeability of the BBB?

Answer 8

butyrate

Question 9

butyrate (SCFAs) has beneficial effects to which 4 neurological/neurodegenerative disorders?

Answer 9

autism, depression, alzheimer’s and parkinson’s

Question 10

which peptides does butyrate disrupt in alzheimer’s disease?

Answer 10

AB

Question 11

which aggregates does butyrate disrupt in parkinson’s?

Answer 11

alpha-s

Question 12

which lysine derivative found n proteins has been found to affect microglia in old mice? what does it increase the production of which can damage DNA?

Answer 12

CML, increases ROS

Question 13

name the 3 types of starch which are prebiotic, giving an example of each?

Answer 13

rapidly digested starch (amyloidose), resistant starch (amylose), raw legumes (amylose)

Question 14

what is the gut bacteria associated with inflammatory bowel disease such as Chron’s and ulcerative colitis?

Answer 14

helicobacter hepaticus

Question 15

which gut bacteria is associated with GI cancer?

Answer 15

H.pylori

Question 16

which gut bacteria is presrnt as babies are breastfed still?

Answer 16

bifidobacteria

Question 17

in the ageing gut, which type of cells die as cells become more senescent?

Answer 17

enterocytes

Question 18

give the 4 species of aerobic gut bacteria

Answer 18

Bacteroides, Firmicutes, Prevotella, Ruminococcus

Question 19

give the 4 species of anaerobic gut bacteria

Answer 19

Peptostreptococcus, Bifidobacterium, Lactobacillus, and Clostridium

Question 20

togther the aerobic and anaerobic species of gut bacteria prevent the overgrowth of what? by competing for what?

Answer 20

harmful bacteria, nutrients and attachment sites to gut mucus membrane

Question 21

When fibre is not available,
which species of aerobic bacteria feed on the protective mucus layer that lines the gut? what can this trigger?

Answer 21

bacteroides, immune response

Question 22

name the 2 metabolites during ageing

Answer 22

phenols and indoles

Question 23

phenols are gut bacterial degradation products of which two substances?

Answer 23

phenylalanine and tyrosine

Question 24

indoles are gut bacterial degradation products of which amino acid?

Answer 24

tryptophan

Question 25

name 4 ways which can alleviate gut inflammation in the elderly?

Answer 25

diet change/add probiotics and polyphenols, faecal mater transfer, oral SCFAs, modulate immune system