MICROBIOTA 1

Question 1

what are humans made of?

Answer 1

eukaryotes+bacteria+ archaebacteria + viruses (bacteriophages)+parasites

Question 2

what is the difference between microbiota and microbiome?

Answer 2

microbiota: cells
microbiome: genes

Question 3

what is the relationship between microorganisms and humans

Answer 3

can fall anywhere on the symbiosis spectrum: mutualism, parasitism or commensalism

Question 4

what is the holobiome

Answer 4

human genome + microbiome

Question 5

why should we care about the microbiome?

Answer 5

Question 6

how is the microbiome traditionally studied?

Answer 6

Question 7

what are some culture independent methods of studying the microbiome?

Answer 7

Question 8

how is 16S rRNA studied?

Answer 8

Question 9

what is metagenomics

Answer 9

Question 10

how do microbial communities distribute?

Answer 10

site specific in the body, they cluster by body site
skin: actinobacteria
vagina: lactobacillus
gut: bacteroidetes and firmicutes
mouth: streptococcus

Question 11

which bacteria are on the skin and what do they do?

Answer 11

composition affects attractiveness to mosquitoes

Question 12

which bacteria are in the oral cavity and the nose?

Answer 12

Question 13

which bacteria are in the urogenital tract

Answer 13

protects against yeast and fungal infections
also varies with sexual activity

Question 14

which bacteria are in the penis microbiome?

Answer 14

Question 15

which bacteria are in the GI tract?

Answer 15

70% of the total microbiome is in the colon
the bacteria vary based on the oxygen levels

Question 16

what is a proxy to analyse the gut microbiome?

Answer 16

fecal samples

Question 17

how do we acquire a microbiome?

Answer 17

feotuses used to be considered sterile
if there is microbes found in the placenta, that is not a good sign
large amounts of microbes are acquired at birth and colonization varies with delivery mode (vaginal or c section)
vaginal delivery: baby gets more vaginal bacteria
c section delivery: baby gets more skin bacteria

Question 18

how does the microbiome change over time

Answer 18

defined succession: establishment of facultative anaerobes (enterobacteriaceae) and bifidobacteria first
after six months, its mostly obligate anaerobes
at 3 years you have adult like microbiota

bacteria phyla remain stable over the course of months but species and strains are much more variable

Question 19

how do you get data that is stronger than correlation?

Answer 19

in vitro studies
animal studies
human studies
each model has limitations
changes in tools technologies and analytical pipelines

Question 20

how are mouse models used to study the microbiota?

Answer 20

Question 21

how are axenic and gnotobiotic mice maintained?

Answer 21

Question 22

what are differences between humans and mice?

Answer 22

mice are coprophagic: they eat each other’s poop
but that means you know that all the mice in the same cage share the same bacteria
only about 30% of bacterial species are shared between mice and humans
but mice models can provide us with means to determine causality and mechanisms of interaction

Question 23

what are holobionths

Answer 23

unit of biological organization composed of a host and its microbiota