BMS1064: Gut and Animal Microbiota Flashcards
(51 cards)
What is milk?
An emulsion of fat and water containing dissolved compounds (protein, minerals etc)
How does bacteria get from mum’s gut to newborn’s gut through breastfeeding?
Dendritic cells go across gut epithelium to directly take up bacteria from gut lumen in mum.
Once associated with DC, live bacteria can migrate via lymph nodes/blood (entero-mammary pathway).
Bacteria arrive at mammary gland and populate colostrum and breast milk.
Milk microbiota, along with breast skin microbiota ingested by infant and reach gut.
How else can infants acquire microbiota?
Placenta, Birth cannel, breast milk…
Once weaned, acquired microbiota from raw foods and environmental factors.
What can spoilage bacteria in milk do to lactose, lipids and proteins? How does this change taste?
Lactose –> lactic acid (sour)
Lipids –> SCFAs (Rancid)
Proteins –> Short peptides (bitter)
What are some examples of pathogenic bacteria found in milk?
Escherichia coli
Staphylococcus
Listeria
Campylobacter jejuni
Salmonella –> all cause gastroenteritis
Mycobacterium -> tuberculosis
What is the microbiome?
The collection of genomes from all the microorganisms present in a particular environment
What is the difference between the gut microbiota and gut microbiomes? How are they identified?
MICROBIOTA
The community of microorganisms living in the gut (microbial profile)
16s rRNA gene sequencing
MICROBIOME
The collective genomes and genetic potential of the microorganisms living in the gut. (microbial potential)
Shotgun metagenomics
Name the main 3 phyla of the gut microbes.
Firmicutes
Proteobacteria
Bacteroidetes
What type of bacteria are Firmicutes bacteria? Give 2 examples.
Gram positive, low guanine and cytosine content
e.g. Bacillus Lactobacillus and Clostridium
What type of bacteria are Proteobacteria? Give 2 examples.
Major Gram-negative group
e.g. E.coli and Salmonella
What type of bacteria are Bacteroidetes?
Gram-negative rods, non-spore forming, anaerobic and aerobic.
Bacteroides and Porphyromonas
What are the functions of the gut microbiota?
- Provides nutrition (vitamin K, B12, SCFAs etc)
- Prevents colonization by detrimental bacteria (competes for nutrients, produces substances that inhibit/kill)
- Stimulates the development of certain tissues (capillaries, intestines, lymphatics etc)
- Stimulates the immune system.
and many more! (ability to gain/lose weight, mood, learning etc)
What are some factors affecting the gut mcirobiota?
Antibiotics and other drugs
Bacterial/viral infections
Diet: high processed, low fibre vs high fibre, fermented
Stress
Radiation and Chemotherapy etc
What are:
- probiotics
- prebiotics
- synbiotics
- postbiotics?
- Probiotics: bacteria that give health benefits
- Prebiotics: non-digestible compounds that stimulate the growth/activity of probiotics (food for bacteria)
- Synbiotics: a mix of prebiotics and probiotics
- Postbiotics: the compounds that good bacteria produce
that promote health
Give example of probiotic organisms
Lactobaacillus spp.
- L. casei
Streptoccocus spp.
Bifidobacterium spp
- B. infantis (breastmilk)
- B. lactis
Sacharomyces boulardii
Enterococcus spp.
What are the characteristics of effective probiotics?
Non-pathogenic/toxis
Able to survive the passage through upper digestive system.
Able to attach to intestinal epithelia and utilize nutrients.
Able to maintain good viability (able to work effectively) and remain stable during storage/processing.
Capable of exerting beneficial effect on the host.
What are some problems with probiotics?
Misleading claims about product viability (able to work)
Detrimental Health effects
What are prebiotics naturally present in??
Breastmilk, Jerusalem artichokes, chicory root, leeks, onions, garlic, asparagus, beans etc.
What are some benefits and issues of faecal transplantation?
Proven to be effective at treating a number of gut conditions.
- Need for standardised protocol
- Need of a perfect donor with appropriate gut microbiota profiling
- Secondary adverse effects and LT implications
What does it mean for bacteria to have selfish behaviour?
They have…
a high rate of resource consumption
high rate of ATP production
high reproduction rate
low biomass production
What does it mean for bacteria to have cooperative behaviour?
low rate of resource consumption
high yield (not rate) of ATP production
low reproduction rate
high biomass production
Lactic Acid Bacteria have specialized in foods with high content of what? What kind of behaviour do they exhibit?
Mono and disaccharides (fructose)
Exhibit selfish behaviour
- high fermentation capacity
- rapid sugar consumption
- accumulation of lactic acid
- ability to propagate in absence of oxygen
Name 3 examples of LAB
Enterococcus
Lactobacillus
Pediococcus
What bacteria is used in the production of wine? What does it do to wine?
Oneococcus (oneo=wine, coccus=round)
Reduces acidity. Increases flavour complexity (nutty, buttery etc)
