Lecture 14 - Microbiome 1 Flashcards
Where are microbes found on the body?
Which area has the most?
Gut - the most
Vagina
Skin
Throat
Why are microbiota important?
Associated with:
• Health
• Disease
What is the Human Microbiome?
Project to sequence all of the genes associated with the microbiota
Compare the bacteria at the different colonisation sites in the body?
Different phyla, depending on the location
How many phyla are represented in the human microbiota?
Only a few
What is meant by ‘humans are superorganisms’?
Humans have evolved to collaborate with microbiota, giving us properties that we would not have on our own
What are the general benefits of microbiota?
- Enhanced digestion
- Intestinal deelopment
- Protection
How do commensals aid digestion?
Degrade polysaccharides
Vitamin K
How do commensals aid development of our gut?
Epithelial cell maturation
Angiogenesis
Lymphocyte development
How do commensal protect us from pathogens?
- Occupy a niche
- Competition for nutrients
- Stimulate the immune system
What are the main phyla found in the microbiome?
Bacteroidetes
Firmicutes
Actinobacteria
Which phylum is only rarely found in the microbiome?
Proteobacteria (E. coli)
Which is the most common phylum in the gut?
Firmicutes
Which phylum commonly colonises the skin?
Actinobacteria
Are most of the bacterial phyla represented in the human microbiome?
No - relatively few phyla are found in the human microbiome
Describe the distribution of bacteria within the gut
More bacteria as we progress down the GIT
Describe the changes in the microbiome over one’s lifetime
When we are healthy, are microbiome is stable
At the extremities of life, our microbiome can be unstable
What factors influence the microbiome?
- Age
- Diet
- Mode of delivery during childbirth
- Breast feeding
- Antibiotics
What is the effect of fever on the human microbiome?
Changes the makeup of the microbiome
Increase in number of actinobacteria
Over the first 2.5 years of life, what brings about the major changes in the microbiota in the gut?
The introduction of solid foods into the diet
Onset of Bacteroidetes
Compare microbiota in twins
Monozygotic twins: less than 50%
Unrelated people: even less
What is the greatest site of antigenic challenge in the body?
The gut
Where do microbiota sit in the gut?
Above the mucin and glycocalyx
How does the microbiota help the innate immune system?
Direct:
• Produce antimicrobials
Indirect
• Interact with PRRs to induce tolerogenic responses
• Produce compounds that maintain the epithelium
