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3.6: Results

  • Page ID
    123033
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    1. Observe isolated colonies on the plates of Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. Record your observations and conclusions.

    Trypticase Soy agar
    Observations
     
    Conclusions
     
    Observations
     
    Conclusions
     
    MacConkey agar
    Observations
     
    Conclusions
     

    2. Using any of the three plates on which they are growing:

    a. Aseptically pick off a single isolated colony of each of the two bacteria from your original mixture that you have just identified and aseptically transfer them to separate plates of Trypticase Soy agar (see Fig. below). Remember to streak the plate for isolation as you learned in Labs 2 and 3.

    Fig. 9: Obtaining Pure Cultures from an Isolation Plate

    Illustration showing how to pick off a single colony from one petri plate and streak it on another plate. Illustration showing how to pick off a different colony from one petri plate and streak it on another plate.
    Copyright; Gary E. Kaiser, Ph.D. The Community College of Baltimore County, Catonsville Campus CC-BY-3.0

    b. When picking off single colonies, remove the top portion of the colony without touching the agar surface itself to avoid picking up any inhibited bacteria from the surface of the agar. Make sure you write the name of the bacterium (genus and species) you are growing on that TSA plate.

    c. Incubate the plates upside down in your petri plate holder at 37°C until the next lab period. These will be your pure cultures for Lab 5 (Direct and Indirect stains).

    pick_0zjc.gif
    GIF animationPicking Off a Single Colony from a Plate Culture. (Copyright; Gary E. Kaiser, Ph.D. The Community College of Baltimore County, Catonsville Campus CC-BY-3.0)

    Contributors and Attributions

    • Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS)


    3.6: Results is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

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