技術(shù)文章
當(dāng)前位置:首頁 > 技術(shù)文章 > 詳細內(nèi)容
Belcher/Knight: Electrocompetent Cells
點擊次數(shù):2736 更新時間:2010-10-20

Saponin Lysis of RBCs

 

Electrocompetent Cells

From Danijela Dukovski at Harvard Medical School. This protocol works well. --Julie Norville

Materials

DI water
10% Glycerol
 

Special Equipment

Centrifuge
Ice water bath
Liquid nitrogen
 

Method

Grow 500ml culture to OD 0.5 (approximay).

Spin down cells 5 times in ice cold 10% sterile glycerol.

Keep everything on ice and use a refrigerated centrifuge.

Each time you resuspend use a progressively smaller volume, and make sure all the cells are well resuspended. At the end resuspend in an appropriate volume. It should be pretty cloudy but not super dense. I just do it by eye, so it comes out about like the competent cells you buy.

Aliquot into Eppendorf tubes (I use 250-500uL, depending on how much I have and how lazy I am), freeze in liquid nitrogen, and store at -80.

How I usually do the washes: spin, resuspend in 250ml spin, resuspend in 100ml spin, resuspend in 50ml (can switch to Falcon tubes here) spin, resuspend in 25ml spin, resuspend in 10ml spin, final resuspension

Sometimes I cut one of these out depending on how much of a hurry I am in. I think the final volume (depends on the intial OD of your cells) usually ends up being 5-10mL, so you can get quite a few aliquots.

For transformation usually use 40-50uL of competent cells per transformation with a few ul (2-3) of ligation.


上一篇:Transforming chemically competent cells 下一篇:Saponin Lysis of RBCs

分享到:

返回列表 | 返回頂部