Human Microbiome

Question 1

Humans as a superorganism

Answer 1

-some archaea and eukaryotic species but dominated by bacteria
-high number of phaes are also present
-100 bacterial genes for every human gene

Question 2

human microbiota

Answer 2

-collection of microbes living on/in us

Question 3

human microbiome

Answer 3

-microbiota and environment they live in

Question 4

dysbiosis

Answer 4

-altered microbiota that is unhealthy for the host
-typically though of as being out of balance
-loss of important commensals
-increased microbes associated with diseease

Question 5

things weved learned about the microbiota

Answer 5

-composition and how it changes over time
-factors that influence composition
-links between microbiota composition and health and disease

Question 6

some things weve learned very little about the microbiota

Answer 6

-community dynamics and how microbes interact
-links between microbiota as causual or correlative and the mechanism
-effiicient ways to restore healthy microbiome to an individual with dysbiosis

Question 7

similarities between microbiota of different people

Answer 7

-similarities at the phylum level

Question 8

differences between microbiota of different people

Answer 8

-differences at species level

Question 9

is microbitoa more environmental or genetically affected

Answer 9

-environment
-there is a genetic component

Question 10

resilience of microbiota

Answer 10

-changes with different conditions but generally returns to original composition
-loss of resilience can lead to dysbiosis
-resilience makes interventiosn challenging as it is difficult to displace existing microbiota

Question 11

where are microbes in and on our bodies

Answer 11

-GI tract
-skin
-oral cavity/upper respiratory tract
-urogeneital tract

Question 12

do microbes differ by location

Answer 12

-yes
-communities also vary signifcantly within these areas

Question 13

GI tract microbiota

Answer 13

-low pH of stomach keeps numbers low but a microbial community does exist here
-increasing numbers as you progress-LI has very dense anaerobic population
-through GI tract pH, oxygen content and nutrients avaliablility varies (so does the composition of the microbiotia)

Question 14

protection of the gastrointestinal tract

Answer 14

-epithelium that lines intestine protected by mucus layer

Question 15

mucin

Answer 15

-gel like glycoprotein that serves a barrier function

Question 16

microbes contact with host cells

Answer 16

-most microbes remain in the lumen and dont directly contact host cells
-there are interactions but there is a barrier to prevent routine, direct physical interactions with epithelium

Question 17

variation of gut microbiota

Answer 17

-lots of person-person variation in the gut microbiota
-abundance of different genera varies by orders of magnitude
-even the most abundant genera are absent from some people
-complexity and variability make it difficult to constitue a healthy microbiota

Question 18

Major phyla in the microbiota

Answer 18

-bacteroidetes
-firmicutes
-proteobacteria
-bacteriodetes and firmicutes dominate

Question 19

bacteroidetes

Answer 19

-gram negative
-masters of complex carbohydrate metabolism

Question 20

firmicutes

Answer 20

-very diverse phylum of gram positive bacteria

Question 21

proteobacteria

Answer 21

-generally facultative anaerobes
-rapidly consume any oxygen present
-important for maintaining anaerobic environment
-high proportions of canbe a sign of dysbiosis

Question 22

metabolism of the gut

Answer 22

-tiny bit of aerobic respiration by proteobacteria
-some anaerobic respiration
-lots of fermentations
-baceteriodetes are the primary fermenters that ferments carbohydrates from food or mucin
-SCFA absorbed by host
-many fermentation products deed diverse other organisms

Question 23

four reasons the gut microbiota is very important for human health

Answer 23

-compete with potential pathogens “colonization resistance”
-digest food for us
-produce nutrients that we cant make that get absorbed in the colon
-promote healthy immune system, train out immune sustem and promote immune tolerance

Question 24

gut microbiome links to disease

Answer 24

-undeniably very important for human health
-causual relationship: helicobacter pylori in stomach appears to be cause of stomach ulcers
-disruptions to microbiota early in life that reduce microbiota diversity lunked to asthma and allergies

Question 25

oral cavity microbiota

Answer 25

-lots of aerobic and anaerobic
-growth as biofilms especially on teeth as dental plaque
-biofilms have highly organized and complex community compoisiton

Question 26

skin microbiome

Answer 26

-varies by location of body
-some common members of microbiota are opportunistic pathogens such as s.aureus
-cuts adn wounds lead to staph infection
-produce a number of virulence factors

Question 27

vaginal microbiota

Answer 27

-dominated by lactobacillus
-lactobacillu benefit host by lowering vaginal pH via fermentation products liek lactic acid that help prevent infection
-yeast are healthy but can rise to levels that disrupt the biome

Question 28

probiotic

Answer 28

-live microorganisms that when administeres have a beneficial affect on host
-consuming good bacteria

Question 29

prebiotic

Answer 29

-a substance that when consumed promotes growth of beneficial microbes
-can be simple and effective

Question 30

fecal transplant

Answer 30

-fecal matter from healthy fonor transplantd into a patient
-attempting to reintroduce a normal/healthy microbiota into a patient experience dysbiosis
-C.diff treatment