5 replies to this topic

[Biochick99]

Does anyone know if in the process of purifying competent cells, should the culture be at a specific optical density for the best results?

[macroman]

I didnt get you ...........

[bob1]

Yes!  Check out the original paper by Hanahan 1983.

[banou]

Biochick99, on Sep 28 2009, 10:41 PM, said:

Does anyone know if in the process of purifying competent cells, should the culture be at a specific optical density for the best results?

yes, the OD600 must be at 0.5 which is the log phase of bacterila growth.

[microgirl]

Biochick99, on Sep 28 2009, 01:41 PM, said:

Does anyone know if in the process of purifying competent cells, should the culture be at a specific optical density for the best results?

They do need to be at a specific OD but that will be different depending on what bacterium you're making competent. They need to be in log phase. If it's E coli that will be ~0.5 - my way of determining this is when you can only vaguely see the lab light thru the culture!

[hanming86]

0.3 to 0.6 is fine.

sometimes i just took an overnight, diluted 100 fold in fresh LB and let it grow for 2-3 hours.

Never let me down.