Afternoon Everyone!
Myself and Jo came in at 9am this morning, and began filling out our COSHH and risk assessment forms. Although they were a bit of a challenge we managed to get them finished before our PFGE gel came out at 11.30am. Filling out the COSHH form involved making a list of all the chemicals we have used so far within our project, looking up their hazard category (using MDSS – which was very useful!), assessing their exposure potential (glacial acetic acid and ethidium bromide being our highest), steps we could take to protect ourselves (containment level), first aid and how to dispose of them. Our containment level for procedure was 1. The Risk assessment form involved identifying possible hazards within the lab, reviewing control measures we could take to reduce this risk and giving an overall risk assessment rating, ours was medium. I felt that filling out these forms was good practise as next year, during our final year projects, we will be required to do this ourselves for our own projects.
We also watched Mike re culture the Propionibacterium acnes in the anaerobic cabinet, which was really interesting to see!
We then removed, stained and viewed our gel. We managed to obtain much clearer bands and we no longer had very dark areas (large amounts of DNA) within the wells. However we did notice slight band elongation, which is caused by increased temperature. This is expected, as unfortunately the PFGE is still running at 25/26°C, instead of the 14°C it really should be running at.
We therefore decided to keep the smaller amount of DNA we were putting in the wells, keep sealing in the plugs, keep the buffer at 0.5X and not include the initial switch interval as before. In order to reduce the temperature and obtain clearer bands we decided to move the PFGE equipment into the fridge (to run at 6°C). In order to obtain more separation we decided to increase the voltage to 6.0 V/cm. We therefore set up and started a new run with these changes for 24 hours at 6.0 V/cm and with a 45 second switch interval, still using 2 samples of NEB yeast, 2 samples of BioRad yeast and 2 samples of 1Kb ladder. With a second block for 2 hours at 0.6 V/cm and with a 45 second switch interval, in case we weren’t ready to remove the gel.
Really excited to see how the massive change in temperature effects our separations! 🙂
See you all tomorrow!