Confluent culture was suspended in TE 50/50. The lyzozyme was add, followed by proteinase K. DNA was extracted with phenol-chloroform- isoamylic and precipitated with ClNa and ethanol.
You can use some kits for DNA preparation, like Sigma and Qiagen. But the best way to do it is Phenol-chloroform extraction. You can get protocol from Meniatis laboratory protocol. We use always Phenol-chloroforn extracted genomic DNA for sequencing and other quality use. You can monitor quality in agarose gels and also by using UV Spectrophotometry for best results.
I also really loved the QuickExtract solultion from Epicentre. I used it on mouse tail snips to isolate DNA for genotyping, but they have protocols for many types of DNA isolation. This technique takes only 7 minutes and is great for PCR, but may not work well for all downstream applications--it is a "dirty" prep (protein fragments, etc remain in the mix). You cannot get purity from 260/280 ratio because of the solution, but I used it for years on several source materials. They have one specifically for bacterial DNA isolation as well. Your technique depends on what you need to do with the DNA after you isolate it!
http://www.epibio.com/search/search_results.asp?SearchString=quick+extract
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