BIO260H1 Lecture Notes - Lecture 12: Population Genetics, Streptococcus, Deoxyribonuclease
Document Summary
1 bacterial genetics: bacteria have economic, medical, agricultural importance. Regulate biochemical cycles (e. g. sulfur cycle, nitrogen cycle) 60% earth"s biomass, found 400m below sea oor (3297m depth) Arti cal snow made with pseudomonas syringae: human microbiome - gut microbiome. 10x more gut bacterial cells (1014) than cells in human body. 10x more genes in human microbiome than human genes. Associated w/ increasingly large number of diseases. Obesity, periodotis, autoimmune diseases (ms, lupsum arthritis, diabetes, allergies: marine viruses - 3 106 viruses/ml deep sea, 108 viruses/ml coastal waters, vast analytical power. Master plate rich (non-selective) media, supplemented w/ histidine, supports prototrophic and auxotrophic. Replica plate selective media, no histidine, auxotrophic colonies absent. Press sterilized velvet surface on master plate and then on replica plate: penicillin enrichment for auxotrophs. Enables selection for loss of function mutations. Mutagenized culture in rich media centrifuge place in selective media (lacking test nutrient. + penicillin) replica plating to identify auxotrophs (colonies missing from replica plate)
