24 thoughts on “P78 – Thillot

    1. Through a couple 1:10 serial dilutions where plaque assays would be performed on the most diluted tubes of phage lysate and then spot tested to see if there was consistency in plaque morphology(indicating a single phage species).

    1. Due to the receptor proteins on the targeted bacterial cell wall having a specific binding configuration for a specific range of receptor proteins on the phage tail.

  1. What kind of environmental factors determine when a temperate phage will enter the lytic cycle?

    1. Temperature fluctuations in the bacterial cell due to a mounted immune response by the host cell, osmotic(salt) fluctuations, pH change, or decrease in nutrient concentration. Think of the many ways that a bacterial cell can undergo cytotoxic stress and thats when a temperate phage may lyse.

    1. They indicate that our Siphoviridae phage if purified can be archived and used for bacteriophage therapy on known susceptible antibiotic resistant bacteria.

  2. You did an excellent job on your presentation–it was clear why you were doing this research and you went through the methods and conclusions well so that everyone is able to understand the results.

    Why does the phage you found need to be isolated from the corndog phage in order to log it in the database?

  3. Your presentation was excellent–clear aims, methods, and results. Great job!

    Why does the phage you discovered need to be isolated from the corndog phage in order to be logged in the database?

    1. Sorry for the double post, I couldn’t view my original one even after refreshing my screen, so assumed it hadn’t worked.

    2. This is because the ultimate goal of this lab was to isolate a mycobacteriophage for use in phage therapy and so having a contaminate phage in there would make it dangerous for clinical use. Hypothetically the Corndog phage has different properties than our phage of interest so it may increase bacterial resistance through horizontal gene transfer or merely introduce a virus into an individual without any bacteria for the said phage to attack.

  4. Great presentation and great figures! What further purification techniques would you recommend to purify Rigby50 from the CornDog contaminant?

    1. There is research around using certain wavelength of UV light that O-cluster phages are susceptible to that A cluster phages aren’t, allowing the light to burn out these phages. Good question, but further research on this topic would need to be done.

  5. Hello! First, how did you name the corndog phage and how does the corndog contamination impact your results? Great work! Thank you for sharing your research with us.

    1. The Corndog phage was named after the shape of its head. It impacts our results as it compromises our ability to send our phage for archive in possible BP therapy use.

    1. It is because temperature phages have a repressor gene that binds to the promoter site for the lytic genes in their genome. This stops the expression of lytic genes and thus the continued state of lysogenic cycle. Think of the lytic cycle as a shaken soda bottle, where the repressor genes are the cap keeping it from exploding. At any moment once cytotoxicity occurs, the cap can be opened loose.

  6. Do you think that the fact that the bacteriophage wasn’t completely isolated had any effect on your results?

    1. Yes, I do a lot because the restriction enzyme results showed cutting of an O-cluster phage which we know to be for the Corndog contaminate. This makes results of restriction analysis immediately biased.

  7. Can you explain corndog a bit more? I am confused about what it is and its relevence to your experiment.

    1. The Corndog was an O-cluster phage that remained in our phage lysate even after the purification process so it spoils our possibility to send our phage to a clinical research lab for archiving and possible use in phage therapy.

    1. Lytic phages completely lyse the bacterial cell making plaques appear clear(no bacterial growth). Temperate phages are undergoing either lytic or lysogenic, so not all bacteria is killed off leading to fuzzy edges(bacterial growth still occurring).

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