8 - the microbiome

Question 1

what is microflora?

Answer 1

the microbes found within/on a given region/habitat

Question 2

what is microbiota?

Answer 2

description of all the microorganisms that live in a defined region

Question 3

what is mirobiome?

Answer 3

the collective genome of a given microbiota

Question 4

basic taxonomy

Answer 4

domain 
phylum
class 
order 
family 
genus 
species 

we are interested in the strain of the species

Question 5

what genes are used for identifying?

Answer 5

16S rRNA

high level of evolutionary conservation n

Question 6

how to extract 16S rRNA

Answer 6

1) isolate DNA from cells
2) use PCR
3) run in a gel to make sure amplified right piece of DNA
4) send it to a lab to get a chromatogram
5) put it into the database and bioinformatics gives you the species and strain of bacteria

Question 7

what 16S rRNA?

Answer 7

seen in almost all bacteria

function hasn’t changed

gene is large enough for informatics purposes

Question 8

what other genes can be used to identify bacteria other than 16S rRNA?

Answer 8

gryA = DNA gyrase (replication)

recA = DNA recombination

Question 9

what 2 places would you anticipate finding bacteria?

Answer 9

non-sterile regions

sterile regions

Question 10

non-sterile regions

Answer 10

all external 
• skin 
• upper respiratory tract 
• urinary tract 
• intestines

Question 11

sterile regions

Answer 11

• blood
• cerebral spinal fluid
• bladder
• organs
• lower respiratory tract
• womb

Question 12

how does infection mainly occur?

Answer 12

when a bacterium is able to invade a sterile site from a non-sterile site

Question 13

what are the 2 kinds of diversity?

Answer 13

alpha and beta

Question 14

alpha diversity

Answer 14

number of bacteria in a certain area

within a sample

Question 15

beta diversity

Answer 15

comparison between you and a neighbour

between samples from the same habitat

Question 16

what makes up the skin microflora?

Answer 16

microorganisms associated with sweat ducts and hair follicles

if bacteria isn’t washed off it gets into the hair follicles

Question 17

what factors influence your skin microflora?

Answer 17

• host physiology
• environment
• immune system
• host genotype
• lifestyle
• pathobiology

Question 18

bacteria in the digestive tract

Answer 18

• location of most of your bacterial load
• amount of bacteria increases as you go down the body
• fluctuates between individuals
• play a key role in processing complex dietary carbohydrates

Question 19

what are bacteriodetes?

Answer 19

largest phylum of gram negative bacteria

produce sphingosine/sphingolipids

play a major role in digesting complex sugars