McClean: Fixation of Yeast (Bisaria Protocol)
This is the protocol used by Anjali Bisaria for rapidly fixing yeast cells from chemostat cultures to image for both bud index as well as fluorescence. We found that protocol preserved both GFP and mCherry fluorescence well.
- Yeast cells
- Formaldehyde 37% (Sigma-Aldrich, #252549)
- Prepare eppendorf tubes with 50μL of 37% formaldehyde, one per sample.
- Add 450μL of culture to 50μL of formaldehyde in an eppendorf tube and mix by inversion. (The goal is to have a final concentration of formaldehyde around 3.7%. So you can adjust the cell and formaldehyde volumes accordingly, as long as you end up with 3.7% formaldehyde).
- Incubate the tube at room temperature for 15-20 minutes.
- Spin down gently for 5 minutes at 8000rpm in the small eppendorf centrifuge.
- Resuspend cells in 75-100μL of 0.1M potassium phosphate
- Store samples at 4°C until you are ready to image.
Please feel free to post comments, questions, or improvements to this protocol. Please sign your name to your note by adding '''*~~~~''': to the beginning of your tip.
*Megan N McClean The lengthy touchdown PCR program protocol was devised by Megan in the early days of the McClean lab when we were struggling with getting colony PCR to work reproducibly. The program is probably WAY longer and more complicated than it needs to be (and ties up the thermocycler for 4 hours at a time) so it would be worth someone's time to figure out a shorter program. Once you do that, please add it as another colony PCR protocol on openwetware and add a note here.
*Megan N McClean We probaby don't need to be using the Hotmaster Taq nor do we need to be doing 50μL reactions. If someone has some spare time, please try optimizing the protocol to use our super-cheapy Taq (ask Megan for where the stock is) and doing smaller reaction volumes.
Botstein Lab protocols: http://www.princeton.edu/genomics/botstein/protocols/colony_PCR.htm
or instead, discuss this protocol.