Commensal Flora

Question 1

What were the general goals of the Human Microbiome Project (HMP)?

Answer 1

• to establish what organisms live at certain sites on the human body
• to generate genome sequences for reference strains
• to develop new analytical and bioinformatic tools

Question 2

How do the microbes in the oral cavity help the body?

Answer 2

help breakdown food and fight off pathogens

Question 3

What is dental plaque?

Answer 3

extensive growth of oral microorganisms (esp. strep) = thick bacterial layer

strep causes acidified environment = tooth decay if left unchecked

strep is the first microorganism to attach to teeth to begin biofilm formation

as plaque continues, anaerobic bacteria begin to grow

Question 4

Are there any microflora in the lower respiratory tract?

Answer 4

we breathe, so will bring in some bacteria

not sure, though, if they can colonize there

Question 5

What are the functions of the microflora in the GI tract?

Answer 5

• carry out some essential metabolic rxns
  
  • produce vitamins, organic acids, enzymes ect
• absorb nutrients
• digest food

Question 6

Where are the most microflora found?

Answer 6

in the colon

contains 10¹³ to 10¹⁴ microbial cells

Question 7

How is obesity associated w/ the microflora?

Answer 7

obesity is associated w/ changes in the relative abundance of the Bacteroidetes and the Firmicutes in mice

Question 8

Versus obese mice, what are the ratios of the microflora in healthy mice?

Answer 8

high ratio of bacteroidetes and firmicutes

low ratio of methanogens

Food -> Fermentation -> H2

high H2 retards fermentation

Question 9

Versus healthy, what are the ratios of the microflora in obese mice?

Answer 9

low ratio of bacteroidetes

high ratio of firmicutes and methanogens

Food -> Fermentation -> H2 -> CH4

low H2 promotes fermentation, leads to more H2 and more CH4