BIO 326R 1st Edition Lecture 20Outline of Last Lecture I. reporter genesa. beta galactosidaseb. GFPc. Lux CDABEII. Triparental conjugationIII. Biparental conjugationOutline of Current Lecture I. Phylogeny/Relatednessa. Morphological characteristicsII. Woese and 16s rRNAa. Sequencing 16s rDNAIII. Metagenomicsa. Microbiota testingIV. ObesityV. AntibioticsVI. Microbiota CuresCurrent LecturePhylogeny- =relatedness- Classically=> morphological characteristicso Gram staino Cell shapeo Coloro Colonieso Biochemical testsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Growth on particular carbon sources Acid production Gas production- These tests are not great because there is great diversity within the same species—does not tell you much- diversity in bacterial specieso ex: E. coli is considered a species, and an individual has 4,500 genes, but the pan-genome (the complete genome of the species) has 9,500 genes individual E. coli= strain- strain= individuals within a species- each strain is very different even though within the same speciesCarl Woese—16s rRNA (1977)- semantide—Pauling, Zuckerkandlo = sense- containing units Common macromolecules that slowly change over time—relatedness anddiversificationo Used 16s rRNA sequencing Used enzymes, obtained fragments of DNA sequence, and back-calculated to determine sequenceo Came up with the 3 domains of life defined as bacteria, archaea, and eukarya- Now, sequence 16s rDNAo Easier to sequence that rRNAo Highly conserved but sequence changes/differs at variable regions Sequence 16s rDNA and compare sequences by looking at variable regions- What have we learned from 16s rDNA sequencing?o Use sequencing of the genetic material in metagenomicsMetagenomics- Metagenomics= analysis of the genetic material from a population of microbeso Microbial community PCR for 16s rDNA sequenceo Tells you what bacteria is where- Microbiota= bacteria present at a given site- Microbiome= all bacteria on body- Common microbiota tested is gut microbiotao Stable environmento Easy to sampleo Large microbial populationo Good animal models Mice—gnotobiotic mice- Gnotobiotic= germ freeObesity in Humans- Take microbiota from lean and obese people and put in gnotobiotic miceo Mice with lean microbiota were lean and mice with obese microbiota became obeseo Idea is that gut flora is obtained from mother and, in addition, the food you eat selects for bugs that grow well with that nutrient source Ex: high fat diet, gut selects for bacteria that grow well on high-fat foods, gut microbiota selects for these bacteriaAntibiotics- Antibiotics reduce diversity and metabolic capacity of microbiota in the guto Gut microbiota provides you with essential nutrients We can not make some amino acids, but out bacteria can- Gnotobiotic animals do not do well unless on special dieto Gut microbiota break down complex molecules—plant derived moleculesMicrobiota Cures- Clostridium difficile= gut, diarrhea, highly antibiotic resistanto Typically obtained when on high amounts of antibiotics, because so much of yourgut microbiota is killedo Cured with a fecal transplate Colonizing affected people with feces flora to regain gut
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