This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Nigrosin dye Staining tray Sterile toothpicks Protocol: 1. Place one drop of nigrosin onto the center of a clean slide. 2. Using sterile technique, transfer one loopful of B. megaterium to the drop of nigrosin and mix. 3. Spread the mixture evenly on the slide to at least the size of a quarter. 4. Repeat steps 2 and 3 using S. aureus . 5. Repeat steps 2 and 3 using a plaque sample from between teeth, obtained with a sterile toothpick. 6. Let the preparations air-dry. DO NOT heat fix. 7. Examine all stained slides under 100x oil immersion lens. DATA AND OBSERVATIONS 1. Draw observations of cells from your plaque sample and B. megaterium . Plaque sample Total magnification ___________ Total magnification ___________ DISCUSSION 1. Why are negative stains useful? 2. Do you heat fix a negative stain? Why?...
View Full Document