Health & Disease Flashcards
What is the stomach microbiome?
Previously thought to be sterile due to the pH, but has a vibrant community
What is gastric fluid?
Firmicutes, Bacteroideted and Actinobacteria
What are gastric mucosa?
Firmicutes and Proteobacteria more abundant
Duodenum is where in the body?
The small intestine
What is Duodenum?
Adjacent to the stomach
Fairly acidic
Microbiota resembles the stomach
Is the pH in the small intestine more or less then the stomach?
Less but more anoxic
What bacteria is present in the small intestine and attached to the wall at one end?
Fusiform
Why must microbiota of the small intestine compete with the host?
For rapid uptake of small carbohydrates
What microbiota is in the large intestine?
Colon
What is colon?
Enormous number os bacteria and lareg numbers of archaea
What is the large intestine?
A large fermentation vessel, microbes use nutrients from the digested food
What is present in theblarge intestine in small numbers and consume remaining oxygen?
Faculative aerobes
What is not a signifiacant gut bacterium?
E. coli
What are the three major major bacteria phyla?
Firmicutes
Bacteroidetes
Proteobacteria
What phyla dominates?
F and B
Are bacteriodetes gram negative and non sporulating rods?
Yes
What do bacteriodetes do?
Carbohydrate metabolism
Ecode many enzymes not encoded by the human genome
Are Firmicutes gram negative or positive?
Gram positive
What are firmicutes active in?
Carbohydrate metabolism
What do germ-free organisms show?
Vitamin deficiencies
Increased susceptibility to infectious disease
Poorly developed immune systems
Lack of antibodies to bacterial infection
What does colonization resistance show us?
The presence of microbiota that protects the host from colonisation by pathogenic microbes
What are colonization resistance?
The combination of short fatty acid production, direct competition for nutrients and immunologic effects on the host
What does skin bacteria produce?
Fatty acids
What does gut bacteria release?
Antibacterial agents and metabolic waste to help prevent establishement of other species
What are three examples of short chain fatty acids?
Butyrate, Propionate and acetate
What is butyrate?
Main energy source for human colonocytes
Can induce apoptosis of colon cancer cells
Can activate gluconeogenesis (energy homeostasis)
What is propionate?
Transferred to the liver
Regualates gluconeogenesis and regulates satiety signals in the gut through interaction with fatty acid receptors
What are actetates?
Most abundant
Essential for the growth of other bacteria
Used in cholesterol metabolism and lipogenesis, appetite regulation
What is the gut-brain axis?
The interactions between the gut microbiota and the host brain are gaining attention
What disorder is gut dybiosis associated with?
Autisum spectrum disorder
What is maternal immune activation (MIA)?
Caused by viral infection, leads to elevated inflammatory factors in the blood
Can cause child developing autism
What are the harmful effects of the microbiome?
Disease can reault if there is an imbalence in the microbiome, and the noemal, healthy flora is disturbed
What is the reasons that disease can result?
Loss of the benificial effects we’ve already covered
Gain of flora with harmful effects
What are the diadvantages of taking antibiotics?
Has unintended effects on the normal microbiota
What can happens if antibiotics are introduced early in life?
May effect the developing microbiota, immune system
Can cause weight gain
What is the C. diff infection?
Common cause of hospital acquired diarrhoea
Easily spreads to others
Emergence of extermely virulent, toxigenic, anitbiotic resistant strains
What are the symptoms of C. diff?
Mild diarrhoea
Inflammotary lesions
Bowel perforation
Septic shock
Death
Is C. diff gram positive or negative, an aerobe or anaerobe and is it a spore former?
Gram positive
Anaerobe
A spore former
What is the treatment for C. diff?
Transplanting intact microbial community from a healthy person to one with a microbiota associated disease
What is dietry fibre?
Broken down to VFA (acetate, propionate, butyrate) by the microbiota
What do volatile fatty acids do?
Are absorbed by the host and contribute 10& to our daily energy requirement
The efficiency of conversion of fermenatble substrates is inreased by what?
Methanogens which consume molecular hydrogen
What does H2 removal stimulate?
Fermentation making more fermentation products available for host absorption
The treatment of C. diff antibiotics are developed to target what?
The pathogen and limit effexts on the rest of the microbiota
What are the positives to bacteriophage therapy?
Minimal effect on the microbiota
Viruses that target and kill bacteria
Can be developed to target specific pathogens
What do probiotics do?
Replace missing elements of the microbiota
Predates recent attention to the microbiome
What are prebiotics?
Chemicals
Not organsisms
Non digestable carbohydrates that are meant to be metabolised by specific microbes to foster their own growth
