Week 3: Ex. 3--Cultural and Cellular Morphology (simple staining and observation of streak plates)

  1. Discuss and make sure students observe plates from last week, as well as the stock culture plates available this week-- discuss colonies, colony morphology, differences they may observe between bacteria and fungi, etc.
  2. Discuss the oil immersion lens (already mentioned in lecture). Terms: resolution, illumination, magnification, parfocal
  3. Demonstrate how to make a smear of a bacterial culture, starting from a slant, and a simple stain of it.
  4. Discuss cell morphology and grouping (already discussed in lecture).
  5. There will be three cultures available:  NA streak plates of E. coli(48 hr.), B. subtilis(48 hr.) and Staph. epidermidis (48 hr.)--these plates should have been streaked for isolation.
  6. Each student should prepare three simple stains, and work until they get it right and can see the organisms with the microscope and oil immersion lens. It will help if they make extra smears in case a slide breaks or a smear is too thick--then the smears will already be air dried, which will save time if they need to re-stain them.
  7. Demonstrate how to handle loop and tubes aseptically (again). NOTE: I flame tubes before and after inserting the inoculating loop!
  8. All these demonstrations take time! Talk while you are doing them. Have a smear all dry and ready to be heat-fixed so that you don't have to wait for the demo one to dry during your demo.
  9. Don't forget to instruct them to label their tubes and plates correctly. Name (group or individual), date, what's in/on them as a minimum. Recommend Sharpies (or Bic Mark-Its) (over wax pencils). Remember, I get them at Sam's and sell them for 50 cents (at cost) each for my lab, but each group should have one if possible. They sell them at the bookstore too, but they cost more. I’ll get more as we need them.

QUIZ 1 covers weeks 1 and 2 (shouldn't take more than 20 minutes, or be longer than 1 page--I would like copies of your quizzes, in advance if possible): lab safety, use and parts of microscopes, oil immersion lenses, aseptic technique, purpose and technique of streak plates (not just to isolate colonies, but also to allow observation of colony morphology), pure tube cultures, environment plates. You could ask a small question about what they will be doing in today's lab. I have sample quizzes.....

Lab Orders for Week 3

Equipment:
slides, 12 working scopes, loops, immersion oil, lens paper, bibulous paper, stains
Cultures:(per group)
for class (per group):