Microbiome Flashcards
(13 cards)
What is a microbiome
The genes present in all the microorganisms living in association with the host
What is a microbiota
Refers to the actual organisms living on / within a host
What organisms make part of our microbiota
- Bacteroidetes
- Firmicutes eg clostridium
- Actinobacteria eg bifidobacterium
- Proteobacteria eg Escherichia
- Cyanobacteria
- Verrucomicrobia
Summary of part 1
*All phyla of bacteria are represented
*The proportional representation of different phyla of the same throughout the body
*Organisms other than bacteria are not considered part of the biome
*There are almost the same number of bacterial cells in the microbiome as there are human cells in the body
*Yhe closer you get towards the rectum ,the higher the bacterial load
*
Factors affecting bacterial distribution
- Bacterial load
- pH( the lower the pH ,the lower the BL)
- antimicrobials(The higher the antimicrobe /oxygen , the lower the BL )
- oxygen
Factors affecting the GIT microbiota
- Diet : Controls the number of each species
- Enviroment : eg Antibiotics
- Host immune system : Difficult to quantify in humans but some major examples eg IgA
Summary of part 2
- Antibiotics can lead to a permanent reduction in diversity over several generations
- Human breast milk supports the growth of very specific microbes
- Once established ,the microbiota is resistant to change by environmental factors
Summary of part 3
- Produces short-chain fatty acids which function limited to the gut
- Affects the absorption of nutrients eg lipids
- It provides colonization resistance to pathogens
- Short-chain fatty acids are the main energy source for colon cells
- Large bowel microbiota reduces the energy available to the host from food
Function of microbiota
1.Provide enzymes which make energy and nutrients available from food we cannot process eg fiber
- Regulate immunity and metabolism :
* Produces metabolites which are absorbed and provide specific signals which become part of our physiology
Dysbiosis
- Loss of overall diversity in microbiota
- Change in the ratio of the major phyla
- Bloom of a specific bacterium especially one with the potential to cause damage
Define probiotics
Live microorganisms that when administered in adequate amounts ,confer benefit for the host
Define Prebiotics
Non-digestible food ingredients that when consumed in enough amounts selectively stimulate the growth of a limited number of microbe in the gut that confers health benefits to the host
Define Bacteriotherapy
Transplantation of the entire ecosystem
