Results Tables
Table 2: Experiment 2 Staining Observations (5 points)
| Stain used: |
Nigrosin |
| Observations: | Background is stained, bacteria shows up as clear spiral. |
Experiment 2 Post-Lab Questions
1. After visualizing the stained samples either using your microscope or by looking at the sample images provided, describe what physical/visual characteristics you were able to observe after performing the negative staining vs. after performing the simple stain. (5 points)
After looking at the sample images provided, negatively stained bacteria showed up as clear straight spirals against a dark background. Bacteria that are simple stained showed up as dark purple rods-shaped with white background.
2. So far in this lab, you have used one type of simple stain and one type of negative stain, yet there are many other simple and negative dyes available. Pick one simple dye and one negative dye, and discuss how those dyes differ from the ones you used in this lab. Give a scenario in which their use would be appropriate. (5 points)
Methylene blue is another dye that can be used for negative stain.
India Ink is another type of negative stain.
Experiment 3 Results Tables
Table 3: Experiment 3 Staining Observations (5 points)
| Stain used: |
Crystal violet (primary stain) & Safranin (counterstain) |
| Observations: |
Gram-positive appeared as purple and Gram-negative showed up as pink. |