Materials For purifying plasmid DNA from Escherichia coli cells, the Qiagen Spin Miniprep Kit produces quite reliable results. Do not autoclave solutions containing isopropanol or MOPS; use sterile filtration if necessary.

(stored in 4℃) by vortexing repeatedly, leaving no clumps. Transfer the suspension into a round-bottom 13 ml polycarbonate tube. 4. Add 4 ml of buffer P2 (stored in Qiagen buffers box) and mix by covering with parafilm and inverting 4-6 times. Incubate

质粒DNA的提纯是基因工程实验中最常用的试验方法之一，质粒DNA提纯效率和质量与其后续实验步骤（如PCR扩增、酶切、连接、转化大肠杆菌和转染真核细胞等）的成功与否有着直接的关系，因此高效快速地从细菌细胞中提纯质粒DNA 具有重要的意义，本文主要介绍了由QIAGEN plasmid Midi试剂盒方法提取质粒的方法。1. Pick a single colony from a streak plate and inoculate 25 ml of LB with appropriate

      ♦利用真空方式超快速进行质粒纯化，碱裂解步骤后，利用QIAfilter无须离心即可澄清裂解液，然后离心柱安置于真空底座（例如：QIAvac 24 Plus 见图1）上进行DNA的洗涤和洗脱。Midi and Maxi kit 20 分钟内可纯化24 个样本Mega和Giga Kit可分别在40，50分钟内处理12个样本。 ♦QIAGEN Plasmid plus Midi/Maxi Kit 提供优化的高产量protocol 并采取高洗脱体积，确保纯化得到高产量质粒

The RNeasy Mini Kit from Qiagen is designed for RNA extraction, although the basic format is similar to other Qiagen products designed to purify nucleic acids: ion exchange columns specifically bind RNA which is purified by wash steps

according to the Qiagen Maxi or Mega prep protocol. Resuspend the DNA in 3.7 mL of T.E. Add 3.7 gm. CsCl and 0.37 mL of 1 mg/mL ethidium bromide. Check the density of the DNA solusion by placing 0.01 mL (= V) on an analytical balance and recording