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25 Cards in this Set
- Front
- Back
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How many microbes does the human gut have?
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up to 100 trillion microbes
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What is used to identify organisms in the micro biome that cannot be cultured?
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16S rRNA, it is a common method of determining phylogeny
-a unique 16S rRNA = unique organism |
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Who discovered the idea of using 16S rRNA for identifying organisms?
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Carl Woese, Norm Pace, and George Fox
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What is sanger sequencing?
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-utilizes DNA polymerase which terminates when a dideoxy nucleotide is incorporated
-visualize the strand with a radio label or fluorescent |
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What is the capillary method( DNA sequencing)?
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similar to sanger but using different coloured fluorescence for each dideoxy nucleotide and run through one lane on an electrophoresis gel
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What is micro sequencing?
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-take DNA directly from source without using a plasmid
- leads to parallel sequencing and miniaturization which allows for a very high throughput |
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what are some examples of micro sequencing?
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Illumina, Solexa
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How does illumina sequencing work?
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using DNA clusters a single base is added each cycle, the fluorescence is read and then washed away allowing for a new base to be incorporated
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How does pacific biosystems DNA sequencing technique work?
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using special plates with zeptolitre sized wells a DNA polymerase is within each well and will sequence the DNA in real time
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What is ion torrent sequencing?
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DNA is amplified onto a bead and the system measures the change in pH when a nucleotide is added. bases can be differentiated because you will flood only one base at a time
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What is nanopore sequencing?
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engineered protein pores into a physical membrane which will pull ssDNA through and detect the shape of each base by the current that is across the membrane
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What is the human micro biome project?
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-cataloguing the microbes that live in / or on humans
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What were the two approaches to the micro biome studies?
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the 16S approach - sequenced all 16S rRNA and grouped them, then compared to a database: SILVA
Shotgun metagenomic approach - sequence as much fragmented DNA as possible then put it together and compare to reference genomes |
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What did they found with the Human micro biome project?
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there are 18 habitats in 5 major areas form 200 individuals using both a metagenomic and 16S analysis
-looked at what type of microbe was predominant in each area |
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What can the results from the human micro biome project be used for?
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personalized medicine, obesity studies and looking at gnotobiotic organisms
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What is bifidobacteria?
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nonmotile nonsporing rods that are anaerobic
-produce acetic and lactic acid by fermenting carbs, but no gas production -first bacteria you get after birth, can digest sugars in milk that humans can't |
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What is a probiotic vs. a prebiotic
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-probiotics found in things like yogurt
-prebiotic is eating specific foods to encourage the growth or specific organisms based on what you eat |
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What do lean animals have that larger ones do not?
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-a higher proportion of bacteriodetes than firmicutes
-diets show obese patients increasing their population of bacteriodetes |
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What did the study of gut microbiota from discordant twins show?
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that bacteria injected from lean twin into mouse: mouse stayed lean
bacteria injected from obese twin into mouse: mouse became obese |
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what happened to obese mice that were put in cages with lean mice when the mice eat the fecal matter?
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obese mice showed a lower increase in fat mass when with a lean mouse than with an obese mouse
-lean mice stayed the same -the species transferred from Ob to Ln are bacteriodetes |
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How can bacteria of the micro biome modulate behaviour disorders like autism?
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-injected mice with MIA and poly I:C which makes the mouse mimic autism behaviours
-looked at behaviours of normal mice, autistic mice and autistic mice supplemented with B.fragilis |
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What were the results of the different behavioural studies?
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supplementation with the B.fragilis shows a rescue of normal behaviour for anxiety,sensorimeter, burying habits and communication but not for sociability showing that this may not be a cure for autism but it could help
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How is the microbiota affected by antibiotics?
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they will affect the overall microbial communities
-wiping out the diversity takes longer to recover from, bacterial populations in terms of numbers will recover quickly |
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What does Helicobacter pylori do?
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causes stomach ulcers, but amount of it in the gut of both males and females is decreasing over time
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How are fecal transplants used?
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used to treat pseudomonas enterocolitis caused by C.difficile, there was problems treating antibiotic resistant strains so used fecal transplants to treat the bacterial infection
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