Science Buddies: "Ask an Expert"

Hello,
I was wondering if someone could help me with a couple questions I have.
I am using E. coli cultures grown in the presence of glucose, lactose and Glucose + Lactose for my science fair project (Ordered from Carolina Biological, from the Lac Operon kit.) I finished preparing these cultures on January 15th. I was wondering if I could still use these cultures this week? (They've been in the refrigerator, while I have not been using them).

I was also wondering how I should prepare the mediums because I got three prepared mediums (Without the sugars) from Carolina. If LB broth would work or not.

Thank You.

HI,

The e. coli are in general pretty hardy, but you want them to be in log phase of growth before putting into expirimental conditions. Do you have the e coli in liquid cutlure or on plates? If on plates, pick colonies and grow up in LB (or the medium you have from carolina) and they should be good to use. If in liquid culture, mix the content good (bacteria should be settled to the bottom, you need to get them in the solution), then take 1/2 - 1 ml and put in LB to grow up, then they can be used.

Yes, LB should grow the e coli very well. Let me know if you have other questions.

Tonya

Thank you for responding.
Yes, the E. coli is in liquid cultures. So the cultures from the 15th would still be good to use?
Thank you so much.

Yep. Do what i said above to get them back in log phase growth and you should be set. Let me know if any issues come up.

Tonya