Difference between revisions of "Team:WLC-Milwaukee/Notebook"

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<p>In order to justify these steps, we attempt to quantify the effect of our process of phage solution enhancement. In order to test the protocol’s effectiveness, our experiment made use of two phages. One TolC-binding phage, TLS phage, and one non-TolC-binding phage we isolated ourselves called Phage #4 (we found that mipA, fhuA, fecA, and flgH knocokout E. colis, were insensitive to this phage). To begin the experiment we infected bacterial cultures (separately) in order to proliferate our phages; 1 mL of overnight grown WT E. coli (wild type) was mixed with 10 mL of LB and 250 µL of isolated phage solution. After incubating overnight at 37°C, these tubes were centrifuged. The supernatants were moved to new tubes; these were treated with chloroform, centrifuged, and the supernatants were again moved to new tubes (these are our starting phage solutions). From there four new tubes were labeled (TLS+, TLS-, 4+, and 4-). The “+” tubes became the “enhanced” tubes, and the “-“ tubes were left “unenhanced”; both “TLS” tubes were started with 5 mL of the TLS starting phage solution, and both “4” tubes were started with 5 mL of the Phage #4 starting phage solution. The “+” tubes were enhanced (see steps 2-9 under “TolC Specific Bacteriophage Screen” above) adding 30 mL of volume to the original 5mL of phage solution. To compensate for the gained volume, the “-“ tubes had 30 mL of sterile LB added. </p>
 
<p>In order to justify these steps, we attempt to quantify the effect of our process of phage solution enhancement. In order to test the protocol’s effectiveness, our experiment made use of two phages. One TolC-binding phage, TLS phage, and one non-TolC-binding phage we isolated ourselves called Phage #4 (we found that mipA, fhuA, fecA, and flgH knocokout E. colis, were insensitive to this phage). To begin the experiment we infected bacterial cultures (separately) in order to proliferate our phages; 1 mL of overnight grown WT E. coli (wild type) was mixed with 10 mL of LB and 250 µL of isolated phage solution. After incubating overnight at 37°C, these tubes were centrifuged. The supernatants were moved to new tubes; these were treated with chloroform, centrifuged, and the supernatants were again moved to new tubes (these are our starting phage solutions). From there four new tubes were labeled (TLS+, TLS-, 4+, and 4-). The “+” tubes became the “enhanced” tubes, and the “-“ tubes were left “unenhanced”; both “TLS” tubes were started with 5 mL of the TLS starting phage solution, and both “4” tubes were started with 5 mL of the Phage #4 starting phage solution. The “+” tubes were enhanced (see steps 2-9 under “TolC Specific Bacteriophage Screen” above) adding 30 mL of volume to the original 5mL of phage solution. To compensate for the gained volume, the “-“ tubes had 30 mL of sterile LB added. </p>

Revision as of 08:33, 17 September 2015




Documentation





Here is where we should put a brief description of the content that fits under the SURVEYS category:


it lives?
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Here is where we should put a brief description of the content that fits under the RESULTS category:


Western Blots

In order to look for phages for specific organism’s TolC proteins, we had to first make sure the proteins were being produced. In all, we isolated the TolC genes for Salmonella, Vibrio cholera, Yersenia pestis, Proteus, Pseudomonas, Klebsiella, and E. coli K12. These were put under the control of the pBAD promoter and a strong E. coli RBS, and the E. coli tolC signaling sequence was put upstream the different organisms’ tolC genes. Using the Western Blots, we were able to show that the proteins were being transcribed, and transcription levels were raised in the presence of the pBAD promoter’s inducer- arabinose (at 0.1% working solution). Note: basal levels of transcription in Luria Broth are sufficient for function (see Kirby-Bauer assays which were done without the inducer) and phage binding (see the example phage plate in Modeling > Experimental Verification, which was also done without any inducer).

Kirby-Bauer Assays

Pictured are Example Kirby-Bauer assays. Note that the zones of inhibition are small for the WT E. coli (top left)
and much larger for ΔtolC E. coli (top right).
Some transgenic tolC proteins can restore efflux function to ΔtolC E. coli,like that
of Proteus (bottom left), but not all work- for an example see Pseudomonas's tolC (bottom right)

The Kirby-Bauer assays were the second part of our expression tests. While the western blots tested for the production of the proteins, the Kirby-Bauer assay is testing whether or not the expressed TolC is having an impact on sensitivity to two efflux-resisted antibiotics: Novobiocin and Erythromycin. The Kirby-Bauer assay is a simple test that involves plating what would become a lawn of bacteria (using Top Agar); on top of this filter disks containing an antibiotic are placed. The antibiotics diffuse from the disks and inhibit the growth of bacteria within a certain distance based on the concentration of antibiotic at that distance and the minimum inhibitory concentration (MIC) of the antibiotic against the specific bacteria plated.

In the Kirby-Bauer assays, wild type (WT) E. coli, ΔtolC E. coli, and a ΔtolC E. coli with the pUC57 plasmid containing the pBAD promoter and the strong RBS (everything but a gene) were used as controls. The WT E. coli had smaller zones of clearing, indicating reduced sensitivity to the antibiotics compared to the two other controls, as expected. The rest of the samples were ΔtolC E. coli expressing a transgenic tolC gene contained on a pUC57 plasmid behind the same pBAD promoter-strong RBS combination. A Kirby-bauer showing zones of clearing similar in size to the WT E. coli was interpreted as TolC proteins being successfully assembled, inserted into the membrane, and successfully interfacing with other membrane proteins to form a functional trans-periplasmic efflux pump. Zones of clearing similar to the ΔtolC control were interpreted as a failure interface with other membrane proteins to form a fully functional trans-periplasmic efflux pump. It is impossible to say based on the Kirby-Bauer assays if these failures were due to failure to polymerize, insert into the membrane, or interacting with the other membrane proteins in the efflux pump.

Kirby-Bauer assays were analyzed by taking a picture of the plates from the same height (using a stand) and keeping a ruler in the image. The pictures were analyzed using the ImageJ software package. A conversion was set between pixels and centimeters using the “Set Scale” function. A circle was made to reflect the zone of clearing and its properties were exported as a .csv. Excel was used to convert from the circumference to the diameter of the zone of clearing, and each diameter was expressed as a percentage of the ΔtolC E. coli’s zone of clearing’s diameter.


Results of Kirby-Bauer assays done on ΔtolC E. coli with our transgenic molecules.
Green signifies results that indicate a restoration of efflux function in ΔtolC E. coli.

Phage Solution Enhancement

Our project aims to act as a chassis for collecting and isolating new bacteriophages specific to the TolC proteins of pathogenic strains of bacteria, using a safe lab-strain of E. coli. To be used in such a way, we modified a preexisting protocol for isolating bacteriophages from the environment. In doing so, we added three rounds of what we referred to as “phage solution enhancement.” The idea behind this is that the environmental phage source is incubated with a larger volume of overnight-grown ΔtolC E. coli for ~20 minutes; this should be enough time for any bacteriophages capable of infecting these knockout-tolC cells to have an opportunity to bind a host bacterium, but not enough time to replicate and release new phage particles into the environment. These incubations are then chilled and centrifuged. The pellet created at the bottom contains the ΔtolC E. coli and any non-TolC specific bacteriophages which bound/infected the ΔtolC E. coli. The supernatant, which contains any bacteriophages which did not bind, is moved into a new tube, treated with chloroform to kill any remaining bacteria, and moved into another new tube. This becomes the new phage solution and the process is repeated twice more. The protocols are included in the table below.

Bacteria-Specific Phage Isolation Screen TolC Specific Bacteriophage Screen
  1. Pipette 5 mL of your environmental sample into a 50 mL conical tube
  2. Add 35 mL LB broth to conical tube
  3. Add 1 ml overnight grown E. coli culture (or any bacteria of interest)
  4. Incubate overnight shaking at 37°C
  5. Centrifuge the 50 mL conical tube for 10 minutes at top speed
  6. Pour supernatant into new conical tube (throw tube with pellet in biohazard bin)
  7. Add 2 ml Chloroform to tube containing supernatant
  8. Vortex vigorously for 1 minute
  9. Centrifuge 50 mL conical tube for 10 minutes at top speed
  10. After centrifugation chloroform will form a layer on the bottom and supernatant on the top
  11. Remove 25 mL supernatant and put in new 50 mL conical tube
  12. Attempt to filter-sterilize the supernatant into a new conical tube using a 45µm filter (often there is still too much debris in the solution so the filters become clogged very quickly.)
  13. Perform plaque assay with this phage sample (see plaque assay protocol)
  1. Pipette 5 mL of your environmental sample into a 50 mL conical tube
  2. Add 10 mL culture of ΔtolC E. coli
  3. Mix and incubate standing at 37°C for 20 minutes
  4. Centrifuge tube for 10 minutes at 4500rpm and 4°C
  5. Pour supernatant in new 50 mL conical tube (dispose of pellet in biohazard bin)
  6. Add 2 ml Chloroform to supernatant
  7. Vortex vigorously for 1 minute
  8. Centrifuge for 10 minutes at top speed
  9. Repeat steps 2-8 a total of 3 times
  10. Remove 10 mL of this now phage solution into new conical tube (Store tube in refrigerator after use)
  11. Pipette 1 mL of this phage solution into new 15 mL conical tube
  12. Add 8 mL LB broth to conical tube
  13. Add 1 mL wild-type E. coli culture or ΔtolC E. coli expressing another type of ToC (add antibiotics to the mixture to a working concentration if needed).
  14. Incubate mixture overnight shaking at 37°C
  15. Next day, centrifuge the conical tube for 10 minutes at top speed
  16. Pour the supernatant into a new conical tube
  17. Add 1 mL chloroform to supernatant
  18. Vortex vigorously for 1 minute
  19. Centrifuge tube for 10 minutes at high speed
  20. Transfer phage solution into new conical tube
  21. Perform plaque assay with the same wild-type E. coli strain or ΔtolC E. coli strain with plasmid tolC used previously
  22. After plaques have been isolated on plates, purify the phage from several plaques and test whether they use TolC as a receptor using a cross-streak of wild-type E. coli, the ΔtolC E. coli with a plasmid containing another tolC (if used), and the ΔtolC E. coli

In order to justify these steps, we attempt to quantify the effect of our process of phage solution enhancement. In order to test the protocol’s effectiveness, our experiment made use of two phages. One TolC-binding phage, TLS phage, and one non-TolC-binding phage we isolated ourselves called Phage #4 (we found that mipA, fhuA, fecA, and flgH knocokout E. colis, were insensitive to this phage). To begin the experiment we infected bacterial cultures (separately) in order to proliferate our phages; 1 mL of overnight grown WT E. coli (wild type) was mixed with 10 mL of LB and 250 µL of isolated phage solution. After incubating overnight at 37°C, these tubes were centrifuged. The supernatants were moved to new tubes; these were treated with chloroform, centrifuged, and the supernatants were again moved to new tubes (these are our starting phage solutions). From there four new tubes were labeled (TLS+, TLS-, 4+, and 4-). The “+” tubes became the “enhanced” tubes, and the “-“ tubes were left “unenhanced”; both “TLS” tubes were started with 5 mL of the TLS starting phage solution, and both “4” tubes were started with 5 mL of the Phage #4 starting phage solution. The “+” tubes were enhanced (see steps 2-9 under “TolC Specific Bacteriophage Screen” above) adding 30 mL of volume to the original 5mL of phage solution. To compensate for the gained volume, the “-“ tubes had 30 mL of sterile LB added.

Expecting high phage concentrations in some of our new phage solutions, we performed 1:10 serial dilutions (of which 100µL of the total 1000µL of each dilution would be used) on all of our new phage solutions down to a concentration of 10^-12. All these dilutions were mixed with 250 mL of overnight grown WT E. coli culture and 4 mL of molten LB top agar; the mixtures were immediately plated. After ~24 hours of incubation at 37°C, the plates were analyzed. Plates with a countable number of plaques (between 30 and 300) were chosen for each type of phage solution. These were used to calculate the number of plaque forming units per milliliter (PFU/mL). The “+” solutions’ PFU/mL’s were divided by those from the matching “-“ solution, to obtain a fractional change in phage concentration from the enhancement process. We expected a fractional change of approximately 1 from TLS+/TLS- and a number significantly less than 1 for Phage #4.





Here is where we should put a brief description of the content that fits under the Explore category:


April 26th-May 2nd
This week we assembled our team for the summer, and ended the week out with a BBQ to get to know each other!


April 26th-May 2nd
A brainstorming meeting occurred and we had a great time formulating our lab work, wiki, and policy & practices parts of our projects. Committees will be important for us to accomplish everything.


May 3rd – May 9th
A brainstorming meeting occurred and we had a great time formulating our lab work, wiki, and policy & practices parts of our projects. Committees will be important for us to accomplish everything.



May 10th – May 16th
Speakers for our summer camp were finalized and rooms reserved! XXX


May 17th – May 23rd
We had a final meeting in our committees before breaking for summer. Projects were started and last details decided upon so we could make the most of our summer!


May 24th - May 30th
Bioengineering Summer Camp lead coordinators, Matt and Sierra met with MSOE to discuss what activities and models we would use for our students at the summer camp.


May 31st – June 6th
XXX


June 7th – June 13th
XXX


June 14th – June 20th
XXX


June 21st – June 27th
Matt and Sierra proposed a final wiki design which the team agreed upon. Onto coding!


June 21st – June 27th
XXX


June 28th – July 4th
XXX


June 28th – July 4th
XXX


July 5th – July 11th
The student lecturers, Matt and Sierra, at our summer camp began formulating their presentations about viruses and antibiotic resistance! We are pumped to share our knowledge to help high schoolers understand antibiotics and use them appropriately in the “real world”.


July 12th – July 18th
This week was all about finding questions to ask our experts: Sierra focused on doctors, Christa focused on industry specialists, and Anna focused on foundations that all work with antibiotics, antibiotic resistance, or bacteriophages.


July 19th – July 25th
Preparations were made for our summer camp next week! Food, name tags, lab manuals, and binders are waiting for our campers and staff members! We are so excited to meet our students and work with them over the week!


July 26th – August 1st
Summer Camp week! Read about the blast that we had with our students HERE***. Unfortunately, lab progressed fairly slow due to our staff dedicating a majority of their time to the summer camp, but no regrets, as our students had a wonderful time.


August 2nd – August 8th
This was a major background research week. Sierra, Christa, and Matt focused on source gathering, journal reading, and article writing galore! Phage therapy and bacteriophages are fascinating to read about, find our sources around the rest of the wiki!


August 9th – August 15th
Jordyn proposed, and Sierra finalized drafts of surveys for our WELS high school teachers and WLC students. Now onto sending them out and collecting responses and data.


August 16th – August 22nd
XXXX


August 23rd – August 29th
We welcomed new freshman on our campus this week! Sierra and Harrison had a table at "Org Smorg" to recruit for next year's iGEM team as well as survey the freshmen about their knowledge and opinions regarding GMOs. Jack made sure we looked great with a new poster board made up for the event. Matt, Sierra, and Dr. Werner also decided on the program we would pursue. ***


August 30th – September 5th
We were back on campus this week! It was great to see the entire team again. We had a team meeting on September 1st and got caught up with our tasks ahead of us. We prepared for Biotechnology Info Night, designing the coffee lids and deciding the content of our session. We also prepared for having lunch tables to gather survey data.


September 6th – September 12th
This week was a big week for Policy & Practices. We had lunch tables at our school for students to have conversations with us regarding biotech and take our survey. We also encouraged them to come to Biotechnology Info Night.


September 13th – September 19th
This week, unfortunately, was a large wiki building week. We focused a lot as a team on uploading content and finalizing all of our Policy & Practices data. Zach, Anna, and Jack analyzed surveys while Sierra coordinated who was responsible for what content. Christa focused on wiki proof reading, and Ryan contributed to graphic design. Jordyn and Harrison ensured that all of our requirements were fulfilled and documented. Matt, the wiki master coder, made sure that we had pages to upload content to. In lab, ***.