Several of the manuals in the laboratory have material on identification of unknowns. You need to examine the information in more than one to get a flavor for the kind of strategies recommended. See "Identification of Bacteria" in Bergey's Manual, Vol 1, p 24-26 (located in the Biology Reading Room). Especially note the sections on "Pure Culture" and Approaches to Identification of an Isolate". Your experience with virtual laboratory activities using "Identibacter Interactus" (on the BioLab1 Mac in SC 205) should aid you for this stimulating laboratory adventure. Remember, good preparation in advance will frequently lead to fewer disappointments. You may want to prepare plates or other materials prior to the lab meeting so you are ready to do the first steps immediately upon receiving the unknowns. You may want to form teams to make media as needed.
Simulated Unknowns are taken from among bacteria available in our laboratory
1. Prepare in advance an Outline of Strategy using the suggestions from the lab manuals or Bergey's Manual. This may be a flow diagram or a list of the steps you will take to identify two "unknowns" from a mixed liquid culture.
2. Get approval of your strategy from the instructor. Be prepared to explain the rationale for each step, the kinds of information you expect to get from each, and the next steps to take for each possible result.
3. Obtain a tube with a mixture of 2 unknowns from laboratory strains.
4. Implement your strategy.
5. Complete isolation and identification by March 31 .
6. Present a pure culture of each unknown on an agar slant (complete labeling is required).
7. Present one Gram stain with appropriate controls for each identified culture slant (complete labeling is required).
8. Your report is to be included in your lab book. It should contain a summary of the strategy you used to isolate and identify the two unknowns. Please give the sequence of steps, including rationalle and results for each step, that you used to identify each organism. In short, what did you do to collect evidence and what did you find out?
Note: The "unknown" mixture will be in the very best condition immediately after it is available. If you are not prepared to work on it immediately, the risk of loosing one of the unknowns is much higher. Old cultures get increasingly less reliable, and mixed cultures are especially troublesome.