Wednesday, October 01, 2003
Description REFERENCE: Molecular Cloning: A Laboratory Manual, 2nd ed., pp.1.25-1.28. Procedure Grow up a 5 ml culture overnight in the presence of the appropriate antibiotic. 2. Harvest 1.5 ml of culture by centrifugation in an Eppendorf tube. 3. Resuspend the pellet in 100 l of ice-cold solution 1. 4. Store for 5 minutes at room temperature. 5. Add 200 l of solution 2 and mix the contents by inverting the tube rapidly two or three times. Do not vortex. 6. Store for 5 minutes on ice. 7. Add 150 ul of ice-cold solution 3 and mix by vortexing in an inverted position. 8. Store for 5 minutes on ice. 9. Centrifuge for 5 minutes in a Eppendorf centrifuge at 4C. 10. Transfer supernatant to a fresh tube and add an equal volume of phenol/chloroform. Mix by vortexing the tube and centrifuge for 2 minutes in an eppendorf centrifuge at room temperature. 11. Transfer the top layer to a fresh tube and add two volumes of ethanol. Vortex gently and let stand at room temperature for 2 minutes. 12. Centrifuge for 5 minutes in an Eppendorf centrifuge at 4C. 13. Remove supernatant and add 1 ml of 70% ethanol. Vortex briefly and recentrifuge. 14. Remove supernatant and dry the pellet briefly in a vacuum dessicator. 15. Add 50 l of TE (pH 8.0) containing DNase-free pancreatic RNase (20 l/ml). Recipes 1. TE buffer 50 mM glucose, 25 mM Tris-Cl (pH 8.0), 10mM EDTA (pH 8.0); filter sterilized and stored at 4C. 2. 0.2N NaOH (freshly diluted from 10N stock), 1% SDS; This solution should be made up fresh on the day of use. 3. 3 M potassium and 5 M acetate. Store at 4C. 60 ml of 5 mM potassium acetate 11.5 ml of glacial acetic acid 28.5 ml of H2O Supplies Tips (责任编辑:泉水) |