Topic 16 - Human Microbiome

Question 1

Learning outcomes

Answer 1

1. Explain how microbe exposure is a threat to human health and also required for normal body development and function.
2. Explain how the mammalian gut evolved to accommodate a microbiome.
3. Describe the primary contribution of the gut microbiome to normal human function.
4. Explain how bacterial numbers differ between the stomach, small intestine and colon.
5. The immune system needs to balance support of the beneficial gut microbiome with control of the threat of microbe escape.
6. Explain how the regulation of the microbiome is important for normal development and health throughout adult life.

Question 2

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Answer 2

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Question 3

Symbiosis spectrum of microbes

Answer 3

Amensal:
- No ongoing interaction
- One party is removed

Parasitism:

Commensalism:

Mutualism:

Question 4

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Answer 4

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Question 5

Bacteria

Answer 5

• Most microbes in all mammals come from 2 bacterial phyla and have fermentative metabolism

bacteriodetes
Firmicutes
Proteobacteria

Question 6

Archaea

Answer 6

• 1 or 2 species
• 1 type of metabolism
• Growth on 1-Carbon compounds and hydrogen

Question 7

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Answer 7

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Question 8

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Answer 8

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Question 9

Nutrient control

Answer 9

• Determines population and activity of the gut
• Encourages functions we need

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Question 10

Immune functions…

Answer 10

• Contain bacteria activity in the gut
• Punishes activity we dont need

Question 11

Defence against pathogens

Answer 11

• Involves colonisation resistance, barrier functions, immune functions

1. Colonial resistance:
   - Normal microbes prevent pathogens from entering the body
2. Barrier functions:
   - There is a strict tipping point as on one side of the gut cell it is tolerated but on other it is not
   - Seperation of body from microbes

Question 12

Pathogens

Answer 12

• Can directly damage host by producing toxins or tissue destrucive enzyme
• Can also be obstructive rather than destructive

Question 13

Immune responsed

Answer 13

When body thinks microbe is in the wrong place
- inflammation
- Programmed cell death
- Production of antibodies

Question 14

Dysbiosis

Answer 14

• A term for disease of a poorly functioning symbiosis
• A breakdown in the balance of the body and microbes