Making Agar Plates with Petri Dishes

Biochemistry, Molecular Biology, and Cell Biology Protocols >> Making Agar Plates with Petri Dishes

To make LB agar, add 15g/litre of agar to the LB broth
1. using the liquid cycle, autoclave the above recipe in a sufficiently large bottle (the solution should use only 80% of the maximum volume of the bottle), remembering to loosen the cap of the bottle; ask someone to show you the correct use of the autoclave, and remember to wear gloves when putting solutions in or out of the autoclave
2. pre-label the bottom of the plastic petri dishes with the antibiotic name, your name, and the date
3. after autoclaving, when the solution is cool enough that the hand can hold it, add antibiotics:
ampicillin—add 1 ul per m LB (stock concentration of ampicillin at 100 mg/ml; final concentration of ampicillin at 100 ug/ml; stock solution of ampicillin made in sterile water, mixed, filtered, and stored in 1 ml aliquots at - 20 degrees C)
4. swirl around the LB agar containing the antibiotic
5. pour onto the plates, leave the plates half open
6. when plates solidify, turn upside down
7. store in the cold room, with either a plastic bag around it or seram wrap around it, and labelled with your name