Most summers we have around 20 students working in the Microbiology and Molecular Biology lab, SB209, in the Science Building on the Brayford Pool campus. This is a place for those students to share their experience.
//Already run my PCR today – the joys of running 2-step PCR as opposed to 3-step.
Running out the fragments on a 1.5% gel at the moment but because I want coffee I’m running it slowly – 80V for 2.5 hrs.
Against a 100bp ladder.
//Hey All,
Removed plugs from SpeI enzyme, buffer and BSA, and washed in 1x wash buffer for 30mins. We removed this, then incubated them in 0.5x TAE buffer for an hour, while we prepared a 1.4% agarose gel. We then loaded 1/2 of each plug strain into individual wells, as well as the low range PFG marker, sealed with agarose and ran at 6V/cm, for 15 hours, with a 1-12 sec switch interval, and modified buffer flow.
Tomorrow, we will remove the gel, stain it and view it. We will also be filming our last videoblog! 🙁 as it will be the last day of our project – 10 weeks has gone by sooo fast! We may also be running another gel, depending on the results of the first. See you all then 🙂
//Hello All,
Unfortunately the re cultured samples hadn’t grown enough on Monday to use, so we left them another day and night until Tuesday. Today, although the growth was minimal we decided to start plug making. We added chloramphenicol to the samples, left them for an hour, and then centrifuged them all down until we had appropriate sized pellets. However, some of the samples did not readily form pellets, and several pellets were much smaller than others or were very dark in colour.
We then combined the pellets with cell suspension buffer, shook them to combine and added agarose. We then pipetted the samples into plug molds and left them to solidify in the fridge. Once solid, we pushed each plug into a separate eppendorf, added appropriate lysozyme, buffer and mutanolysin. However one plug hadn’t soldified enough and was discared. They are now incubating at 37C. At 6, i will remove the lysozyme, buffer and mutanolysin, and add proteinase K and buffer. Incubating them overnight at 50C.
Tomorrow we will be washing the plugs, and incubating them in restriction enzyme, buffer and BSA.
//Hey All,
When we checked the growth of the 10 different strain samples of propionibacterium acnes this morning we were happy with most of them, expect a few which were still abit clear. We decided to proceed anyway with plug making, adding chloramphenicol to them for a hour, then centrifuging down 3ml of all samples.
We then centifuged the others further down until all pellets appeared the same size and roughly the same size as the previous most successful plug making. While doing this we melted agarose in a waterbath slowly at 50C.
Once all pellets were appropriate sizes, we added cell suspension buffer, eluted the pellets and added agarose. We kept the agarose, cell suspension buffer and cells at 50C, and pipetted each sample into a mold. Producing 1 plug per sample.
Once solidified, we pushed each plug into a separate universal, added lysozyme, buffer and mutanolysin. This is now incubating at 37C until half 7/half 8pm. After which Mike will remove lysozyme, buffer and mutanolysin and add proteinase K and buffer, incubating it at 50C until tomorrow morning.
Unfortunatly we ran out of lysozyme and proteinase K buffers, so Mike had us make up our own from 1M tris HCL pH8 buffer, sodium dodeyl sulphate (SDS), 0.5M EDTA pH8 and pure water.
Tomorrow we will be washing the plugs and incubating them in SpeI. See you all tomorrow!
//Hello,
Today i began by removing the gel, staining it and viewing it. The gel was much cleaner than before, and the low range PFG marker showed very clear bands, while the restriction enzyme treated plug showed some separation but blurring as before. This confirmed that the problem lies with the plugs, not the settings. Which will hopefully be cleaned up, after DNA conc. is increased in the new plugs.
I began plug making as the Propionbacterium acnes 6919 strain sample had nearly grown enough. Mike suggested i use 2 tubes of 10ml Propionbacterium acnes 6919 strain sample, add chloramphenicol and centrifuge down all 10ml of both samples. This produced a large pellet that i then eluted in cell suspension buffer and combined with agarose. I then pipetted this into 5 plugs molds, and left these to solidify. Once this had happened, i pushed them out into a universal, added lysozyme, buffer and mutanolysin and left to incubate at 37C, for 5 hrs. I then removed this, and added proteinase K and buffer, and incubated overnight at 50C.
Tomorrow i will begin washing the plugs, and treating them with SpeI.
//Evening,
Today we washed our plugs, as before in 1X wash buffer 4 times for an hour each. We then separated our 5 plugs into separate eppendorfs, and put 3 in storage in fresh 1X wash buffer. To the 2 remaining plugs we added 0.1X wash buffer for an hour.
To one we removed the wash buffer and added 1ml of Spe1 buffer to saturate for an hour. We then added fresh Spe1 buffer, Spe1 enzyme and BSA, and incubated overnight at 37C.
We set up a new gel in order to run the unrestriction treated plug, to ensure that the DNA within the samples are viable for use. If we see one large band just below the wells, that is as clear or clearer as our best previous gel run, then we will run a gel with the same settings, but with restriction enzyme treated plugs.
We made up 3L of TAE 0.5X and a 1% gel. We removed the wash buffer from the other plug and added 1ml of TAE 0.5X buffer to saturate it. Once the gel had set, we cut and placed 2 non restriction enzyme treated plug sections and 2 sections of the new low range PFG marker into the wells and sealed with agarose. We ran this gel at the low range PFG marker settings: 1% agarose gel, 15 hours, 1-12 second switch interval ramping and 6V/cm.
I also filmed with Sophia and Barney, regarding their experiences in the lab so far! 🙂
We will remove this gel tomorrow, stain it and view it. This will help us to decide whether to run the restriction enzyme plug, with the same low range PFG marker settings.
See you all tomorrow!
//Evening All,
Didn’t come into the lab till 4pm today, in order to allow our Propionibacterium acnes 6919 strain to grow sufficiently. We took 7ml of the Propionibacterium acnes 6919 strain added 14ul of chloramphenicol and incubated for an hour. Then we pipetted 1ml into 2 eppendorfs and spun them down for 5 mins at full speed. Once pellet, we added 250ul of cell suspension buffer into both, shook and then combined. We then added 500ul of melted agarose and pipetted into 5 plug molds. We then put them into the fridge to set.
We have left them in the fridge till tomorrow, when we will treat the plugs with lysozyme, mutanolysin and proteinase K.
See you all tomorrow! 🙂
//Afternoon,
Quite a quick day today, came into the lab stained and viewed our gel. We saw little/no separation from the Propionibacterium acnes 6919 strain restriction enzyme plugs and the non restriction enzyme plugs. However we did see separation from the NEB yeast.
Myself and Jo decided that this may be due to our newest plugs. As mentioned before one of the pipettes we were using was full of liquid, and therefore may have given us incorrect amounts of substances when being used. We were unsure as to whether this was resulting in no separations from plugs on our latest gel, so we decided to run another gel with 2 samples of our old Propionibacterium acnes 6919 strain restriction enzyme plugs, and 2 samples of our new Propionibacterium acnes 6919 strain restriction enzyme plugs, along with one sample of new non restriction enzyme plug and 1 sample of NEB yeast.
We are hoping that by doing this we can establish if the lack of separation is due to our new plugs being poor, or the settings recommended by the new ladder – low range PFG marker, not being quite right. We set up the gel ad ran it with the same settings as yesterday – 15hrs, 6 V/cm, 1-12 second switch interval ramping, 1% agarose, and then a second block to hold the gel at 0.6 Vcm, 5 second switch interval until tomorrow morning when we will be in to remove it, stain it and view it.
Filming our newest videoblog tomorrow… 🙂
//Hey Everyone,
Came into the lab this morning to start to set up our next gel. I made up 3 L of TAE 0.5X, incubated 1 Propionibacterium acnes 6919 strain restriction enzyme plug and 1 non restriction enzyme plug in 1X wash buffer and then in 0.5X TAE buffer. I then made up a 1% agarose gel and left it to set. I put the gel and plugs into the fridge and left them until 5pm.
When i came in at 5pm, i cut and loaded 2 samples of Propionibacterium acnes 6919 strain restriction enzyme plug, 1 sample of non restriction enzyme plug and 1 NEB yeast ladder. I sealed the plugs and then ran the gel according to the info recommended on the low range PFG marker ladder, for 15hrs, at 6 V/cm, with a ramped switch interval from 1-12 seconds. I added a second block as the gel is only running for 15hrs, and will finish at 8.30am tomorrow morning, of 0.6V/cm for 2hrs with a 5 second switch interval.
We will hopefully have the new ladder tomorrow, so we can modify our new gel according to the results we get when the run finishes tomorrow and use the new ladder!
See you all tomorrow 🙂
//Evening All,
Today myself and Jo started our second batch of plugs, made from 10 different Propionibacterium acnes patient samples and a Propionibacterium acnes 6919 strain. We followed the same protocol as before, but made 4 plugs from the Propionibacterium acnes 6919 strain and 2 plugs from each of the 10 different Propionibacterium acnes patient samples. Mike checked their OD to ensure appropriate cell density (0.25). We also centrifuged down 2 eppendorf tubes containing 1ml of the same sample to pellet, we then eluted the pellet in 200ul of suspension buffer each, in order to produce a cell concentration of 2 x 10^8 ,we then removed 100ul.
Having agarose divided into separate eppendorfs was very useful when melting agarose to combine with the centrifuged samples.
However we did experience a few problems, when trying to pipette the agarose and centrifuged sample into the molds some bubbles formed, and some samples appeared to contain less then others resulting in some plugs being half the size of others. We decided that this was most likely due to one of our pipettes being inaccurate due to liquid internally, and that we only produced exactly how much we needed, resulting in some being lost during the procedure. In order to correct this Mike took apart and emptied the pipette for us, and we planned to modify the method to produce slightly more (10%) to allow for losses.
After the plugs had set, we separated them all into separate eppendorf tubes, added lysozyme and buffer, mutanolysin and incubated for 3 hrs at 37ºC. We then added proteinase K and buffer and left overnight to incubate.
We also discussed more appropriate ladders with Mike, he showed us afew that might be better to use, such as http://www.neb.uk.com/productcatalogue/productinfotransfer.aspx?id=/New%20England%20Biolabs/Markers%20and%20Ladders/PFG%20Markers/N0340.
We decided that tomorrow during plug washing, we would use the online genome cutting software we have used before to find exactly how many and what size fragments Spe1 would produce when lysing Propionibacterium acnes so we could make a final decision on ladder size range, and order one asap.
See you all tomorrow! 🙂
//Hi,
today luke did water filtration with water from the Brayford and innoculated nutrient agar plates with the filtered discs and incubated them at 30C for two days. The mannitol salt agar plates that had been spread plated with water from the Brayford showed large yellowy mucoid colonies, this was a positive for a Staphylococcus species. Using a sample from the mannitol salt plates and from the E.coli luke streaked the day before, Sharon and Luke performed Gram stains to compare the colonies. We then made up 1000ml of 50X TAE, and a 1% agarose gel for Steve. I have confirmd two more of my bacterial cultures, hopefully tomorrow i can inoculate them into broths and then into stabs and slopes.
//Hello Everyone!
Came into the lab today, removed, stained and viewed our latest gel. We observed a clear similar band under all the samples not treated with restriction enzyme, and slightly blurry similar band under all samples treated with restriction enzyme. Although the position of the bands are correct, the blurriness suggests that separation is still not occurring properly. There also appears to be a problem with the sealing agarose, resulting in very dark wells as DNA cannot properly leave the wells. This was actually my fault, as when making up the sealing agarose for the wells, i had been mixing the same 1g of agarose used in making the actual gel, in the smaller amount of buffer (50ml) used when making the sealing agarose, instead of halving the agarose to 0.5g. Therefore we were attempting to seal the wells with 2% agarose, which explains the difficulty we had in pipetting it (the formation of bubbles), the dark wells and smearing of samples through the gel.
We decided on the following modifications:
We then ran a standard 0.8% agarose gel, with 0.5X TAE buffer, for 2 hours at 100V. We ran 3 large samples of restriction enzyme treated plugs, 1 Kb ladder and lambda Hind III ladder. We sealed the plugs in with 0.8% agarose (0.4g agarose and 50ml 0.5X TAE buffer).
The results of this confirmed our modifications, and tomorrow we will be running a new PFGE gel for 24 hours, at 4 V/cm with a 20 second switch interval, applying our modifications.
See you all tomorrow 🙂
//Hey All,
Today we came in removed, stained and viewed our gel. The samples not treated with restriction enzyme showed a similar band, just underneath the wells. This was expected as the samples had not been treated and therefore lysed by the restriction enzymes, so separation according to size did not occur, producing only one/two bands. The samples treated with restriction enzyme showed some separation, but not enough, possibly due to not enough digestion. For both sample types it appeared that the largest plug size used worked the best. Mike also noted that this may be due to a lack of cell density within the plugs. The agarose gel also appeared very messy, and needed to be cleaned up. We destained the gel in TAE buffer, viewed it again and decided on the following modifications for our next PFGE run:
Excited to see if our modifications produce clearer band separation 🙂
//Evening Everyone!
Didn’t come into the lab till the afternoon today. Once we got in we removed the buffer from the plugs, and incubated them further in 1X wash buffer for 30 mins, at room temperature. While this was incubating myself and Jo made up 3L of 0.5X TAE buffer, melted agarose and then poured a new gel. The buffer was then removed and replaced with some of the 0.5X TAE buffer, that will be used to run the gel, to allow equilibration. We then cut and loaded 3 samples of fully treated Propionibacterium acnes DNA, 3 samples of Propionibacterium acnes DNA not treated with the restriction enzyme (SpeI) and 1 sample of lambda Hind III as a reference ladder.
Finally we sealed the plugs in with agarose and set the PFGE to run for: 12.7 hours at 6.0 V/cm with a ramping of 1-8 seconds, then 7 hours at 6.0 V/cm with a ramping of 0.1-2 seconds. We haven’t tried ramping before, but we decided to try this set up, as it is the method used in one of the journals we have been working from. Ramping is where one switch interval is used at the beginning of a time run, and another is used at the end, therefore over the time period the ramping slowly changes.
Tomorrow we will be filming our next videoblog, removing, staining and viewing our gel. As mike won’t be in, we will be discussing modifications and a plan for next week on Monday.
See you all tomorrow! 🙂
//Good Evening Everyone!
Busy day today! Myself, Jo and Mike discussed possible modifications to the plug making method when using Propionibacterium acnes. We decided that we would need to use mutanolysin, which aids in cell lysis, as Propionibacterium acnes can be difficult to break into! We also decided to prolong the incubation time after the addition of mutanolysin and lysozyme from 2 hours to 3 hours at 37°C, in order to give them plenty to time to work on the Propionibacterium acnes.
We then began running through our first attempt at making the plugs! We started by adding chloramphenicol to our Propionibacterium acnes TYGE broth (that Mike inoculated for us). Once that had incubated for an hour we centrifuged it at full speed for 5mins, until we obtained a pellet. We then eluted this pellet in cell suspension buffer. We melted agarose and added these together. We then pipetted this into plug molds, which required a bit of practise! (we made 10 plugs) and left them at 4°C, to solidify. Once set we removed them into a universal tube and added lysozyme, it’s buffer and mutanolysin, it was then incubated at 37°C for 3 hours. We then removed the plugs and rinsed the plugs with pure water. We then added proteinase K and it’s buffer and left it to incubate at 50°C, until tomorrow morning.
We will be washing the plugs A LOT tomorrow! 4 times per plug 1 hour each, with wash buffer! We will then be working through the restriction enzyme digestion of the plugs info, and hopefully get ready to set up our first run with our hand made plugs! 🙂
See you all tomorrow!
//Hello Everyone!
Myself and Jo got into the lab early this morning, in order to set up our next PFGE run with our new modifications. We made up 3L of 0.5X TAE buffer and 150ml of agarose (in order to reduce error), then left the gel to set. While it was setting we made up 50ml of agarose to seal the plugs into the wells. We then cut up 4 samples of NEB yeast, pushed them into the wells and sealed them up with agarose. We then set up the PFGE equipment to run at 6°C, for 15 hours at 6 V/cm with a 70 second switch interval and then for 11 hours at 6 V/cm with a 120 second switch interval.
The run is to finish at 12.15pm tomorrow, so myself and jo will be in the lab from 11am to film our second videoblog section! 🙂
See you all tomorrow morning!
//Evening all!
Myself and Jo spent this morning researching the next stages of our project, then we came into the lab for 3pm, in order to take our gel out of the PFGE. We then stained it up and viewed it with Mike. We saw much better separation than before, with the bands reaching all the way to the bottom of the gel, and running off. Both yeast samples, BioRad and NEB, also appeared consistent with each other. The 1Kb ladder was not visible, which was expected. However, the separations slightly shifted to the right, producing wonky bands, that unfortunately weren’t very defined. Mike said this was most likely due to imperfections in the agarose, and we could rectify this by producing 150ml of agarose in order to reduce error. In order to try and stop the yeast sample running off the gel we decided to change our switch interval as well. We also decided that as the NEB yeast has been the most consistent and successful sample, we would stop running the BioRad yeast and 1Kb ladder. We will keep the size of the plugs the same, and well as sealing them with agarose.
Reviewing the NEB yeast information we decided to try running our next gel following the guidelines provided, 1% agarose, 15 hours at 6 V/cm with a 70 second switch interval and then 11 hours at 6 V/cm with a 120 second switch interval. Using 0.5X TAE buffer, 2 samples of NEB yeast and at 6°C as before.
See you all tomorrow morning as we set up our next, and possible last gel before starting on our next stage in the project! 🙂