Week 2: Ex. 2--Transfer and Isolation Techniques, Microbes in the Environment, pp. 17-29

1. Introduce/reinforce the idea of aseptic technique (procedures designed to prevent contamination in both directions--that is, of the environment and of the pure cultures. Point out the Lysol, BonAmi powder, etc. at each station. Have them clean slides with BonAmi before and after using them.
2. Demonstrate the complete process of aseptic tube transfers. No caps should be on the benchtop (hold with fingers of opposite hand from tubes), and they should learn to hold two tubes at once in the same hand! Make sure you can do it.
3. Demonstrate the complete process of preparing a 3- or 4-section streak plate. I prefer a three section plate for this level of student--I think the success rate is higher. Also I prefer for them to use a Sharpie to mark section divisions on the agar side of their plate. Be sure they label their plates on the side attached to the agar, not the lid. Also be sure they know to incubate the plates (agar-side up) in their locker if the sample was collected at room temperature and in the walk-in incubator if it was collected at body temperature.
4. Be sure to point out the purposes of making a streak plate at all! (To obtain isolated colonies for observation of colony morphology and for preparation of pure cultures--two purposes!)
5. The media for this week include 1 NB tube and 1 NA slant for each person to practice tube inoculations, 1 NA plate per person to try a streak plate, and 1 NA plate per person to expose to the laboratory (or other) environment. The culture is to be share by all the members of a group.
6. Be sure they take time to get organized before they begin.
7. Remind them that these are techniques they will be graded on later (streak plate) or that will determine how well they do on other exercises (tube transfers).

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   For preparations manager:
   Calculate amounts of most media as follows (unless otherwise specified):
   6 lab sections x 6 groups per lab = 36 groups (minimum--make enough for at least 39 groups)
   (multiply all amounts given per group times number of groups and make a few (10%) extra!)
   

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   Lab Orders for Week 2

   Cultures:

   1 NA slant of E. coli per group

   Equipment:

   for class: slides, 12 working scopes, loops, immersion oil, lens paper, bibulous paper, stains

   Media:

   4 tubes nutrient broth per group

   4 tubes nutrient agar slants per group

   8 NA plates per group

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