The Human Microbiome Flashcards
What is the human microbiome?
The community of bacteria that live in/on the human host.
Characteristics of germ free animals (5)
Live longer and have less diseases because they see less pathogens
Enlargement of caecum and have degenerate diseases of intestinal tract, because they don’t have the same microbes needed to grow
Germ free rats are vitamin deficient as microbes make vitamins
Under development of the immune system as microbes stimulate it
Increased rate of autoimmune disease
What diseases are associated with the population of the microbiome? (7)
Obesity Inflammatory bowel disease Chrohns disease Cardiovascular disease Vaginal infections Eczema Asthma
Key concepts about the foetus (2)
Foetus has no microorganisms
Colonised by bacteria at birth canal then pick up bacteria from the vagina and then mouth
Where us bacteria found? (8)
Gastrointestinal tract (where most is) Skin Genitals Urethra External ear canal External eye Hair Respiratory tract
Where should bacteria not be found? (10)
Middle/inner ear Heart liver Kidneys Brain Spine Muscles Bones Ovaries Glands Sinuses
What is it called when you have bacteria in your brain
Meningitis
What are 5 sterile body fluids
Blood Urine in kidneys Cerebrospinal fluid Saliva (before mouth) Amniotic fluid
Do we have more bacteria in us than cells?
Yes because 1.3 fold more bacteria found than cells
2 types of bacteria
Firmicutes
Bacteriodetes
Firmicutes (4)
Gram negative (2 cell walls)
Importance of ratio of bacteriodetes and firmicutes
Take simple sugars and make short chain fatty acids
Form spores
Bacteriodetes (6)
Form spores
Anaerobic Don’t need O2 (can be killed by it)
Gram negative
Break down carbs (by bacteria prevotella) and sugars
Lives in soil, seawater and animals
Some say can cause obesity
Effects of fermentation on dietary fibre by the microbiome
Bacteria in colon metabolise dietary fibre into oligosaccharides (cell recognition and binding), and monosaccharides (made into short chain fatty acids and absorbed by colonic epithelial cells to make them healthier).
Verrucomicrobia
Beneficial bacteria that treats cancer by blocking ‘check point’ on immune alleles and stop cancer. It works on 1/4 people.
What is the link between asthma and antibiotics?
Children given antibiotics at a young age will be more likely to get asthma
How to identify a microbiome
Sequence all microbial DNA and identify all microbial species
What is metagenomics
Culture dependent study of genomes of many organisms simultaneously
Eg human microbiome project
Human microbiome project results
The amount of firmicutes and bacteriodetes vary with diet and differ in each area of the body.
Define commensial bacteria
Symbiosis that benefits bacteria and doesn’t harm the host. Most are anaerobes.
Define microbiota
Community of microbial organisms that inhabit a body site
Define dysbiosis
Changing the microbiome in comparison with a healthy state
