CMB1003/L07 Human Microbiota

Question 1

What is the ratio of human cells to microorganisms in the body?

Answer 1

1:10

Question 2

Give 2 methods of detecting/finding microbes.

Answer 2

Culturing
DNA/RNA sequencing

Question 3

Describe culturing of microorganisms. (2)

Answer 3

Growing live microbes tested in lab-based mechanistic studies
Required for development of therapies

Question 4

Describe DNA/RNA sequencing. (2)

Answer 4

Determine microbial community ‘fingerprint’
Rapid and high-throughput

Question 5

Give 4 NGS microbiome profiling approaches.

Answer 5

Genus level profiling
Metagenomics
Species/strain level + functional ‘potential’ profiling
Metatranscriptomics

Question 6

Describe the importance of culturomics identification and culturing of ‘unknown’ microbes. (4)

Answer 6

Improve reference databases for further NGS approaches
Phenotypic/mechanistic studies
Culture collections
Therapy development

Question 7

How many species are able to colonise the colon?

Answer 7

2500+

Question 8

What are HMOs? (3)

Answer 8

Human milk oligosaccharides
Aim to induce growth of gut microbiota
Prime immune system

Question 9

Describe gut microbiota composition in infancy. (3)

Answer 9

Pioneer microbes
Low diversity
High instability

Question 10

Describe gut microbiota composition in toddlers. (3)

Answer 10

New species out compete early ones
Rapid increase in diversity via diet
High instability

Question 11

Describe gut microbiota composition in adulthood. (2)

Answer 11

Highly distinct, diverse microbiota
Microbiota community may continue to change, but at slower

Question 12

Describe gut microbiota composition in elderly people. (2)

Answer 12

Substantially different microbiota than younger people
Lower diversity

Question 13

Give 2 ways in which microbiome can be affected during pregnancy.

Answer 13

Intra-uterine environment
Maternal exposures
Length of gestation
Weight at birth

Question 14

Give 3 ways in which microbiome can be affected during birth.

Answer 14

Mode of delivery
Contact with mother or healthcare professionals
Environment straight after birth

Question 15

Give 3 ways in which microbiome can be affected following birth.

Answer 15

Feeding modality
Antibiotics
Weaning or food supplementation
Home or family setting
Home structure

Question 16

Define colonisation resistance.

Answer 16

Resistance to colonisation by ingested bacteria or inhibition of overgrowth of resident bacteria normally present at low levels within GIT

Question 17

Give 3 ways in which colonisation of the GIT is a difficult task.

Answer 17

Competition for nutrients
Direct killing
Competition for niches

Question 18

Describe the role of microbiota in immune programming. (4)

Answer 18

SCFAs produced by bacteria
Strengthen epithelial barrier
Encourage mucus production
Affect immune receptor expression
Affect cytokine release
Recruitment and education of T cells

Question 19

Give 4 potential causes of microbiota disturbances.

Answer 19

Diet
Antibiotics
Birth modality
Infection
Genetics

Question 20

Give 3 types of disease associated with microbiota differences.

Answer 20

Autoimmune
Intestinal disease
Brain-linked conditions
Metabolic disease
Immune disease

Question 21

What was the result of implanting faecal microbiota from growth stunted children into GF mice? (2)

Answer 21

Growth deficiencies in mice
Overcome by addition of growth promoting microbes or specific sialylated milk oligosaccharides

Question 22

What has been discovered about MCDF-2?

Answer 22

Carbohydrates contained in MCDF-2 and genes were needed to digest some carbs