lecture 31

Question 1

what was the aim of the human microbiome project?

Answer 1

characterize microbial communities found at multiple human body sites and to look for correlations between changes in the microbiome and human health

Question 2

what was found out by the human microbiome project?

Answer 2

• Strong niche specialization both within and among
  individuals = different
  sites, different microbes
• very diverse microbiomes amongst individuals

Question 3

how many bacteria species are found in every person? how many are really common?

Answer 3

160, 57 very common

Question 4

what are the functions of the microbiome?

Answer 4

a) Preventing pathogens from being successful
b) Block colonization niches
c) Competing for nutrients
d) Modifying environment to change virulence factor expression
e) Making environment actively hostile: Producing bacteriocins (antimicrobial) & short
chain fatty acids (SCFA)
f) Lowering pH
g) Cause host to thicken mucus layer
h) Cause host to upregulate antimicrobial peptides (defensin, IgA)
i) Primes host neutrophils and macrophages

Question 5

what are the four main bacterial groups found on the human body?

Answer 5

• firmicutes
• bacteriodetes
• actinobacteria
• proteobacteria

Question 6

what are the functions of the gut microbiome?

Answer 6

• has enzymes that digest plant matter
• modulate metabolisms
  -affects defence against pathogens
• synthesise vitamins (B and K)
• modulate immune response
• alter drug delivery

Question 7

what are functional foods?

Answer 7

food claimed to have a health-promoting or disease-preventing property beyond the basic function of supplying nutrients

Question 9

what are prebiotics and their possible benefits?

Answer 9

• an ingredient that beneficially nourishes the good bacteria already in the large bowel or colon.
• stimulate growth of probiotics
• obtained from oligosaccharides
• for better digestion (due to breaking down plant fibres)

Question 10

what are the differences between C. difficile and Lactobacillus? what are the similarities?

Answer 10

• Both use sialic acids from mucins as carbon/energy sources
• heterotrophs
• Speed of growth and presence of accessory genes are the only factors making C. difficile a pathogen