Lab Report

2413 Words Jul 30th, 2010 10 Pages
LAB REPORT NUMBER TWO

DATE: 3/25/2010

inal attachment Lab Experiment number 11
PURPOSE:
To learn the Gram stain technique, the reason for the stain, and how to identify the results of the organisms stained.
MATERIALS:
Bunsen burner, inoculating loop, staining tray, glass slides, bibulous paper, lens paper, oil, and microscope
METHODS:
Apply Crystal Violet (Primary stain) for 1 minute.
Rinse with D-water
Apply Iodine (Mordant) for 1 minute.
Rinse with D-water.
Apply Alcohol (Decolorize) for 30 seconds.
Rinse with D-water.
Apply Safarin (Counterstain) for 1 minute.
Blot dry with bibulous paper.
MICROORGANISMS USED:
E. coli, B. cereus, S. aureus & E.coli (mixture)

RESULTS/DATA USED:
E.coli cell shape was bacilli (rod) with a
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Prepared a bacterial smear of M. smegmatic, S. aureus, & a mixture of M. smegmatic & S. aureus 2. Allowed 3 bacterial slides to air dry & then heat fixed over Bunsen burner 8 times. 3. Set up for staining over the beaker on hot plate, flooded smears with primary stain-crystal fuchsin and steamed for 8 minutes. 4. Rinsed slides with water 5. Decolorized slides with acid alcohol until it runs clear with a slight red color. 6. Rinsed with water 7. Counterstained with methylene blue for 2 minutes 8. Rinsed slides with water. 9. Blot dry using bibulous paper and examine under oil immersion

MICROORGANISMS USED: * Mycobacterium smegmatic * S. aureus * A mixture of S. aureus & M. smegmatic

RESULTS AND DATA USED: 1. M.smegmatic, a bacilli bacteria that colored pink resulting in acid fast. 2. S. aureus, a cocci bacteria that colored blue resulting in non acid fast. 3. M.smegmatic & S. aureus resulted in both acid fast & non acid fast.

CONCLUSION
The conclusion to the acid fast stain is that S. aureus lacks a cellular wax wall causing the primary stain to be easily removed during decolorization, causing it to pick up the counterstain-methylene blue. This results in a non acid fast reaction, meaning it is not in the genus Mycobacterium. M. smegmatic has a

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