Microbiome Flashcards
What is the ratio of bacteria in our bodies to human cells
Almost equal numbers
What two ways can we detect our microbes
Culturing and DNA/RNA sequencing
What is microbe culturing
Growing ‘live’ microbes that can be tested in lab based mechanistic studies
What is an advantage of microbe culturing
Required for development of therapies
What is DNA/RNA sequencing
Determining of the microbial community
What is an advantage of DNA/RNA sequencing
Rapid and high throughput
What is cultromics
Culturing and identifying unknown microbes
What are the advantages of culturomics
Improving reference databases for NGS, important in mechanistics/ phenotypics studies, culture collections and therapy development
What are the disadvantages of culturomics
Expensive and labour intensive
What is the most densely colonised microbial habitat found in nature
Mammalian intestine
How many species of bacteria are capable of colonising the colon
2500+
What creates the distinct niches for microbial colonisation
Broad range of physiological conditions
What is the function of the intestinal mucus
Keeps distance between microorganism and epithelial cells to reduce inflammation
What is the function of the intestinal muscus
Keeps distance between microorganism and epithelial cells to reduce inflammation
What conditions vary throughout the the intestines
Mucus type and thickness, PO2, pH and bacterial load
What drives bacterial colonisation and organisation near the epithelium
Mucus, oxygen, antimicrobial peptides and immune factors
What is the major function of the bacterial species in the colon
Break down complex sugars and indigestible dietary components e.g. fermenting them to make short chain fatty acids
What happens if the diet is low in fibre
Mucus is eroded and depletes enabling bacterial contact and goblet cell death, leading to inflammation and increased risk of pathogens
What oligosaccharide is abundant in breast milk
Human milk oligosaccharide (HMOs)
Describe how the composition of our microbiota evolves during our lifetime
Unborn- sterile
Baby- low diversity and high instability, pioneer microbes
Toddler- Competition from new species, rapid increase in diversity via diet, high instability
Adult- highly distinct and diverse microbiota, changes in community but at a slower rate
Elderly- substantially different microbiota from younger adults, lower diversity
What early life factors influence the microbiome during pregnancy
- intra-uterine environment (bacteria in amniotic fluid), maternal exposures (stress, antibiotics, smoking ect.), length of gestation, weight at birth (<1500g)
What factors influence the microbiome during birth
Mode of delivery (vaginal vs c-section), contact with mother or health professionals, environment after birth e.g. intensive care
What factors influence the microbiome after birth
Feeding modality (breast or formula), antibiotics, weaning or food supplements, home and family setting (urban or rural) and home structure (siblings, pets ect.)
What is colonisation resistance
Resistance to colonisation by ingested bacteria or inhibition of overgrowth of resident bacteria normally present at low levels within the intestinal tract
