Team:BYU Provo/Notebook/SmallPhage/Winterexp/Period1/Dailylog

Overview

March-April

May-June

July-August

September-October

Phage have been purified before

Phage capsids can self assemble

Phage (amber strain) can have their genes knocked out to make a hollow phage

3/18/13

- Priorities List:

Find out how to put drugs into the capsid

Possibly contact F.W. Studier for his amber t7 phage strain

- Next class we plan on growing up phage so that we will have a decent amount of phage to work with. We have several procedures that we plan on testing so that we can see if we can purify the protein capsid. We hope to be proceeding with these as soon as we have phage that we can use. - Another issue that we need to consider is how to get drugs into the capsid.

We need to be able to test and see if we can actually fill our empty capsids with a material.

We have several procedures found in other papers that could possibly help us with this.

3/20/13

- We spent time trying to find a good procedure to propagate phage in a liquid medium. We finally found one that I think will work well for us.

- Today we learned a procedure for how to count phage. - We performed a phage titer on the T4 phage to see if we have a high enough concentration to work with. This is the general procedure: - Phage titer: reported in Pfu/mL (Pfu stands for plaque forming unit)

mix E. coli (500 microL) with 50 microL of phage lysate

incubate for 20 minutes

mix with 4 mL top agar and then plate

holes will appear in the agar that are called plaques

- How we followed it:

We filled five test tubes full of 90 microliters of Liquid Broth each.

We added 10 microliters of our desired phage to the first test tube and then mixed

We took 10 microliters of the first tubes mixed solution and added it to tube 2, and followed the same procedure for each test tube down the line to tube five.

We then labeled 6 culture tubes 0 to -5.

In the first culture tube, we added 20 microL phage to .5 mL bacteria.

In tubes -1 to -5 we took 20 microL from eppendorfs and added to .5 mL bacteria.

We then allowed a 20 minute waiting period for the virus to infect the E. coli.

5 mL top agar was added to each culture tube.

Each tube was then plated and incubated at 37 degrees C.

-The following teammates were assigned phage as follows:

Amber - T2

Arick - T5

Darren - T3

-Results:

We ran into several problems while doing the titer. After we had completed the titer, we found out that the pipet tips we had used were contaminated. When preparing the top agar, we had to melt it in the microwave which caused it to boil over. This also caused a lot of condensation in the plates and caused the auger to crack. This could have caused some contamination. While filling our -5 plate with top agar, there was only enough to put in 4mL of agar instead of the 5mL that was called for in our procedure.

None of the plates had any phage. There was just a lawn of bacteria growing. This could either be because of the problems mentioned above or because the source of T3 was bad. Seeing as nobody else was able to grow any phage we believe that the source was either old or we need a new lab technique.

3/22/13

- Next step: find procedures for purifying different phage. Become experts on phage structure. possibly help with designing point mutations.

osmotic procedure

procedure from Dr. Grose

-Phage structure:

T7 has proteins 10 A and 10 B for capsid, and an assembly protein

T4 has SOC and HOC proteins

- We are currently waiting for our phage to come in so that we can begin running tests to purify the capsid. We have several procedures in mind. We need to prepare the reagents so that when the virus comes in we can immediately begin attempting to purify it. Most of the procedures we have found apply specifically to T7 but we will also try them on T4. We will continue to look for other procedures that may apply specifically to T4.

3/25/13

- Reported on past week and plans for this week

From last week: titering experiment

This week

Learn to make top agar at various concentrations

Background research to determine in vitro assembly vs altering genome – look into specific techniques

Comparing genome of phage and decide on possible site-directed mutagenesis options

- Start working on designing our site directed mutagenesis

Qbeta vs MS2

Look for places where sequences are significantly different

Might be worthwhile to look at capsid structure to identify the regions where interactions between subunits take place

Qbeta vs T7 major

No real consensus – more worthwhile to compare capsid protein sequence of T7 with those that have similar size to it

T7 major vs minor

Minor is longer, but not necessary – the tail overhang is due to ribosome moving two codons downstream instead of three

Suggest we can direct mutation to the poly-U site and prevent ribosome slippage

Qbeta major vs minor

Just continue transcribing after it reaches the stop codon. What does the stop codon code for?

- Research into in-vitro assembly vs direct mutation of phage genome

It seems that we’ll need to clone the genome of the phage into a plasmid and let it assemble in an E coli

Using chemicals we can induce random mutations in phage – might be worthwhile if selection in agar is not working as well.

3/27/13

- More research on genome of enterobacteria phage

Generation of the major and minor capsid in Q beta

Capsid protein information research

Capsid protein sequence comparison

- Outlined protocol for producing stock top agar

4.3 Top Agar Stock Preparation

3/29/13

- Worked on our first team presentation.