lec 1-2 intro and human microbiome Flashcards
effect of microbes on water
drinking water can become polluted e.g. oestrogen from contraceptive pill
what are the challenges against eradication of disease
intracellular infections
multiple host organisms
genetic plasticity
antigenic drift
mechanism for variation in viruses involving accumulation of mutations within the genes that code for antibody-binding sites.
point mutations hemaglutinin and/or neuraminidase genes, encoding envelope glycoproteins
antigenic shift
process by which two or more different strains of a virus, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains.
genetic reassortment of genome segments between animal/bird and human strains
why should we not eradicate infection?
co-evolution is ongoing and natural co-metabolism community stability cost environmental contamination
emerging infectious diseases
have not occured in humans before
occured previously but only small isolation populations affected
gnotobiotic
microbe free
microbiota
microorganisms that inhabit a specific environment
microbiome
all the microbes, their genomes and environmental interactions in a defined environment
dysbiosis
microbial imbalance in or on the body
co-evolution hypothesis
between humans and microbes
microbes have been around for millions more years
why is diversity in gut flora important
allows the natural system the potential to cope with imbalances and change without artificial involvement e.g. antiobiotics
role of gut microbes
immune system regulation removing toxins crowding out pathogens improving intestinal function gut-brain links?
how does hygiene affect microbe populations
increased hygiene in living conditions causes loss in microbe populatons - not there to protect against infection
clean water, c-section, antibiotics
why do babies microbiota differ
c-section or birth canal delivery
different mothers microbiota
where are microbes likely to be found in the body
internal tissues
- they are constantly exposed to environmental microorganisms and are readily colonised by diverse microbial species
conditions of skin affecting types of microbes found
pH
salinity
temperature
HMP
human microbiome project
characterisation of whole microbial communities
ethical issues of HMP
- selection of research participants
- informed consent
- data sharing and privacy
- invasiveness of sample
- how findings are returned to participants
microbiome analysis
DNA analysis
culture independent sequence analysis
reduce bias
- few microbes can be grown in labs
16s RNA sequencing
all bacteria have 16s ribosomes
that sequence is same in all bacteria
metagenome sequencing
whole genome shotgun sequencing of the microbiome
microbial reference genome
catalogue of 3000 genes to be created
phylogenetic tree of 16s similarities
