Determination of a Bacteriophage Titer

Microbiology Lab Report II

Title: Determination of a Bacteriophage Titer

Purpose: To determine the number of phage particles or plaque-forming units in a

suspension of T4 bacteriophage.

Materials:

* 18 - 24 hour broth culture of Escherichia coli B.

* 2 ml suspension of T4 bacteriophages with a titer of at least 10,000 phages/ml

* 5 trypticase soy agar (TSA) plates. These should be warmed to 37c before use

* 5 tubes of soft agar (0.7% agar). Prior to use, melt and hold at 50c in a water bath

* 5 tubes of 9.0 ml trypticase soy (TS) broth

* 1 ml sterile pipettes

* Pipette aids

Methods:

1. We began the experiment by marking the plates and place them in order from 10^5, 10^6, 10^7, then have the blank dilutions ready in order from 10^-4, 10^-5, 10^-6

2. The pipettes was used and pipette 0.5 ml of the phage suspension to the 10^4

3. The next step was pipette 0.5 ml of dilution suspension from 10^-4 and added it to the 10^-5

4. 0.5 ml of dilution suspension was pipette from 10^-5 and add it to the 10^-6

5. We then took 0.1 ml from the 10^-6 and add it into the agar.

6. After adding the dilution into the agar, we added seven drops of E. coli to the soft agar with the Pasteur pipette, and mixed it a little and overlay it the nutrient agar plate.

7. The last step was we waited and let the agar to solidify under the room temperature, after that tape the three nutrient agar plates together and plate them in the incubator.

Result and Discussion:

In this experiment of the bacteriophage isolation and culture, the results were obtained according to the accountable plate count. As shown there were two plaque-forming units in our experiment.

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