To prepare 1M calcium chloride - (Jan/12/2015 )

Hi, I'm given by my supervisor a anhydrous, granular, laboratory grade cacl2 to prepare 1M of cacl2 to make competent e.coli cells

My doubt is about it:

1. Laboratory grade instead of molecular/ultrapure grade

2. Granular form instead of powder form

Will they still give me good results?     

Thanks

Best is always better, but cacl2 soln for making competent cells does not really need best reagents. You are dealing with bugs, not molecules such as DNA, RNA.

You will get good results as long as you do the technique right. In my view the most important part of the technique, and the one that a lot of people get wrong, is using the bacteria grown to early log phase, and no more.

CPRES on Mon Jan 12 17:32:34 2015 said:

Best is always better, but cacl2 soln for making competent cells does not really need best reagents. You are dealing with bugs, not molecules such as DNA, RNA.

 

You will get good results as long as you do the technique right. In my view the most important part of the technique, and the one that a lot of people get wrong, is using the bacteria grown to early log phase, and no more.

 Thanks for the reply. Anyway, what do you mean growing to early log phase is wrong? OD 0.4 - 0.5 should be fine no?

My sentence structure is kind of complicated, but if you read it again, you will see that what I am saying is: "you should culture the bacteria to early log phase".  

OD 0.4-0.5 should be fine, but if you grow'em more than that, that.. no good.