Week 5: Making a Gram Stain

 In this week, I learned how to make a Gram Stain. What is it is really how you can tell if a bacteria is contaminated or not. 


Procedure: 

1) Prepare bacteria on slide. 

   - For bacteria in liquid media/culture, use about 7ug by micro pipetting and place them on slides. 

    - For bacteria on plate, first draw a circle on the slide to mark where you will be putting the bacteria on. Then, use a sterilized loop (using heat) to transfer bacteria onto slide. (Remember to use heat to dry the bacteria on the slide before the next steps.) 

2) Stain the slides with crystal violet for exactly 1 minute. Carefully rinse with DI Water and avoid hitting inside the circle but also try to get most of the excess pigment off of the circle. 

3) Now, bacteria should be bluish purple. Then, stain the slide again with iodine for exactly 1 minute. Carefully rinse again with DI Water. 

4) Drop alcohol for exactly 7 seconds. Quickly rinse with DI Water again. 

5) Lastly, stain the slides with safranin for example 1 minute. Rinse with DI Water. 

6) Blot the slides with bibulous paper to dry them completely.

7) Get out microscope and clean lenses with cleaner. 


Crystal Violet: Primary Stain (Positive Cell) Should be purple 

Iodine: Mordant; fixes crystal violet to bacteria

Alcohol: Decolonization 

Safranin: Dye/Stain (Negative Cell) Should be pink




Comments

  1. EricaOctober 17, 2022 at 5:34 PM

    Anh, don't forget to cite your sources. Nice blog, otherwise.

    ReplyDelete

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