We were given four tasks to complete.
1. Inoculate the broth with your environmental and unknown samples
2. Prepare a streak plate for the unknown
3. Repeat simple stain for both the environmental and unknown samples using the methylene blue stain.
4. Motility test
*When doing each test all of the necessary sterilization processes were observed.*
1.
To inoculate the broth given to us we flamed the loop, took a sample of our unknown bacteria, and after running the mouth of the tube over the flame about three times we stirred the bacteria in the broth. We flamed the opening of the tubes as well as the loop before doing the same for our environmental sample.
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| Broth |
2.
We then prepared a streak plate from the unknown sample that we were given last class.
To create a streak plate we used a sterile loop, sterilized the top of the tube using the flaming technique, took a sample of bacteria, and sterilized the top of the tube again. We then streaked the bacteria on the plate by using a back and forth motion. When streaking the plate we divide the plate into 4 imaginary quadrants.
This culture was then placed in the incubator at 37 degrees Celsius.
3.
We prepared a stain for both our environmental and unknown samples.
The same procedure was done for both.
The same procedure was done for both.
We first placed a drop of distilled water on our cleaned slide. Then after flaming the loop, we took a sample of bacteria and spread it in with the water until a thin mixture developed. Our drop of contaminated mixture was left to air dry.
slide with a drop of distilled water and bacteria stirred into it.
After drying we passed the slide quickly through a flame three times with the smear side up causing the bacteria to be fixed to the slide.
The methylene blue stain was placed on top of the contaminated area. After allowing the bacteria to be stained with the methylene blue for about 1 minute, we rinsed the slide off with distilled water so that any excess stain would be removed.
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| Unknown stain |
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| Environmental stain |
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| Stained Environmental sample (Rod shaped) |
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| Stained unknown sample (Circular Shaped) |
4.
The motility test was done so that we might be able to determine if the bacterium was mobile or not.
We took a sample from our unknown slant with an inoculating needle and stabbed the now contaminated needle into the center of semisolid agar- about halfway deep. We did the same for our environmental slant.
The environmental tube was placed in the incubator at 35 degrees and the unknown was placed in the incubator at 37 degrees C.
placing the sterile inoculating needle in the semisolid agar.
Below is a picture of the mobility test for our unknown bacteria after being incubated at 37 degrees C.
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| As you can see the bacteria only grew within the area where the inoculating needle punctured the semisolid agar = not motile |
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| See the fuzziness around the punctured area = motile bacteria |
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