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20.4: Materials and Procedures

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    • Student Stock Cultures and saline spore solutions:
      • Bacillus cereus
      • Bacillus subtilis
      • Sporosarcina ureae
    • Glass Slides
    • Stain tray and slide holder
    • Stain kit:
      • Malachite Green
      • Safranin
      • Filter paper rounds
      • Hot plate set-up: small beakers of DI water with boiling stones
      • Glass bowls with Sanisol


    Figure \(\PageIndex{1}\): Slide Prep, C.S.Ramey CC-BY-NC-SA
    1. Prepare heat-fixed slides of each culture.
    2. Place a filter paper round on the slide on top of the smear.
    3. Cover the filter paper and slide with Malachite Green and at the hot plate set-ups, place the slide across the top of a steaming beaker of DI water. Steam for 5-10 minutes. While steaming, add additional stain as needed to keep the filter paper wet. DO NOT let the slide dry out.
    4. Remove and discard the filter paper. DO NOT discard in the sink!
    5. Gently wash with DI water (this is essentially the decolorizer step; there is no separate decolorizer).
    6. Counterstain by covering the smear with Safranin for 2 minutes.
    7. Gently wash with DI water, blot, and observe under oil immersion.


    Draw and color (or indicate colors of) your Endospore stain. Label vegetative cells and endospores.


    Contributors and Attributions

    This page titled 20.4: Materials and Procedures is shared under a CC BY license and was authored, remixed, and/or curated by Kelly C. Burke.

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