介绍cbgcbg 22细菌遗传学.pdf

CBG.22 Bacterial G ics 1 Transformation Alain FILLOUX a.filloux@imperial.ac.uk This lecture will cover… • Transformation pr iple • Natural and artificial transformation • Structure of a smid/cloning vector • Map with transformation Books: Pierce, G ics and Snyder, Molecular g ics of bacteria 2 1928: Griffith – Can an extract of dead bacteria g ically transform living cells? 3 1944: Avery, MacLeod and McCarty – What is the transforming pr iple? 4 Transformation Bacteria take up single-stranded from the environment…if they are competent This is orporated into the bacterial chromosome via bination (2 crossovers) After replication and division, one of the resulting cells is transformed. 5 Transformation - Step 1 Arg Mix Arg+ and Arg- recipient cells Arg+ Step 2 + se Single-stranded fragment of Step 3 Extract - Mix with Arg cells Step 4 + NO Arg+ cells NO Arg+ cells Arg+ Select Arg cells