Need help with a dilution problem please! I am extremely stuck. Ou professor wan
ID: 200940 • Letter: N
Question
Need help with a dilution problem please! I am extremely stuck. Ou professor wants us to come up with the exact steps in getting to 1000 CFU per ml from the specified broth culture. Thanks in advance!
Here is the problem:
A broth culture has 5.996 E 6 CFU/ml and we need .0167 microliters to incolate 100 microliters to achieve 1000 CFU/ml. Clearly, this is far below what a P20 pipettor is capable of delivering. Devise a dilution series which would allow you to accurately deliver the correct amount of CFU/ml.
Explanation / Answer
Make serial dilution. Take 6 test tubes mark them with ( A , B ,C,D,E,F) Now full these test tubes with 9 ml of water each. Now take 1 ml of broth ( stock) and transfer it into Tube A and mix gently .Then take 1 ml of solution from Tube A and transfer it to Tube B and mix gently now take 1 ml from B to C And mix .then likewise C to D, D to E and F . If to have 5.96 x 106 stock volume it will dilute 10 6 times. So you have to take test tube E and take 2 ml solution for inculation to achive 1000 Cfu/ ml.