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Lab__3a_Preparing_Bacterial_Smear_for_Differential_Staining

Purple staining gram positive cells pink staining

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- purple staining, Gram-positive cells - pink staining, Gram-negative cells These two types of cells differ significantly in the chemical and physical structure of their cell wall. The structure of the thinner cell walls of Gram negative bacteria cannot hold the dyes previously used, once the decolorizer is applied. + u - G To prepare Gram bacterial smear for staining next week: Draw three circles on slide using wax pen. Also include a “G” to identify that slide will be Gram stained. Flip slide over. Use DI water dropper to place very small drop of water inside each circle. Using a sterilized inoculation loop , take a small sample of your unknown. Be gentle! The bacteria is on the surface of the medium. Swirl into the water in the center circle of your slide. Q: Why are there two additional circles on our slide? Use same method to add controls to circle on left and right. Heat fix the slide on top of your microincinerator . Allow it to stay in the platform for 5 minutes after water has completely evaporated. From the Virtual Microbiology Classroom on ScienceProfOnline.com Watch video of How to Prepare a Bacterial Smear for Gram Staining
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Acid-fast Stain Distinguishes cells that have mycolic acid in cell wall, from those that do not: - purple staining, Nonacid-fast cells (NAF) - bright pink staining, Acid-fast cells (AF) Cell are considered to be Acid-fast if they have mycolic acid in their cell wall. Q: What is mycolic acid, and which types of bacteria have it? + u - A To prepare Acid-fast bacterial smear for staining next week: Draw three circles on slide using wax pen.
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