McClean: Fixation of Yeast (McClean Protocol): Difference between revisions

From OpenWetWare
Jump to navigationJump to search
(New page: <!-- COPY EVERYTHING BELOW HERE TO START YOUR OWN PROTOCOL! --> ==Overview== This is the protocol used by Anjali Bisaria for rapidly fixing yeast cells from chemostat cultures to image f...)
 
 
(4 intermediate revisions by the same user not shown)
Line 2: Line 2:


==Overview==
==Overview==
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 this protocol preserves both GFP and mCherry fluorescence.
This is an adaptation of the protocol used by Anjali Bisaria for rapidly fixing yeast cells from chemostat cultures to image for both bud index as well as fluorescence.  This protocol has been tested by Megan McClean to preserve GFP fluorescence.


==Materials==
==Materials==
*Yeast cells
*Yeast cells
*Formaldehyde 37% (Sigma-Aldrich, #252549)
*Paraformaldehyde 32% aqueous solution (Electron Microscopy Sciences Cat#15714-S)
*0.1M [http://openwetware.org/wiki/McClean:_Potassium_Phosphate | Potassium Phosphate Buffer pH 7.5]
*0.1M [http://openwetware.org/wiki/McClean:_Potassium_Phosphate | Potassium Phosphate Buffer pH 7.5]


==Protocol==
==Protocol==
*Prepare eppendorf tubes with 50μL of 37% formaldehyde, one per sample.
*Prepare eppendorf tubes with 50μL of 32% paraformaldehyde, 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).
*Add 450μL of culture to 50μL of paraformaldehyde in an eppendorf tube and mix by inversion.  (The goal is to have a final concentration of formaldehyde around 3.2%.  So you can adjust the cell and paraformaldehyde volumes accordingly, as long as you end up with 3.2% paraformaldehyde).
*Incubate the tube at room temperature for 15-20 minutes.
*Incubate the tube at room temperature for 15 minutes.
*Spin down gently for 5 minutes at 8000rpm in the small eppendorf centrifuge.
*Spin down gently for 5 minutes at 8000rpm in the small eppendorf centrifuge.
*Resuspend cells in 75-100μL of 0.1M potassium phosphate
*Resuspend cells gently in 250μL of 0.1M potassium phosphate to wash any excess paraformaldehyde.
*Spin down cells gently for 5 minutes at 8000rpm in the small eppendorf centrifuge.
*Resuspend cells in 100μL of 0.1M potassium phosphate
*Store samples at 4°C until you are ready to image.
*Store samples at 4°C until you are ready to image.


Line 21: Line 23:
Please sign your name to your note by adding <font face="courier"><nowiki>'''*~~~~''':</nowiki></font> to the beginning of your tip.
Please sign your name to your note by adding <font face="courier"><nowiki>'''*~~~~''':</nowiki></font> to the beginning of your tip.


'''*[[User:Stephanie S. Steltzer|Stephanie S. Steltzer]] 11:03, 3 August 2015'''  After troubleshooting we found to preserve the GFP fluorescence best, incubate the tube for just 15min at room temp and after it is spun down, wash once in KPO4 (~0.5-1ml) before resuspending cells in 75-100μL of 0.1M KPO4.Also, cells must be imaged day of.
'''*[[User:Megan N McClean|Megan N McClean]] 15:08, 27 May 2016 (EDT)''' This protocol is adjusted from Anjali's original protocol.  Her protocol leaves out the wash step with 0.1M potassium phosphate buffer, which is very important for keeping the formaldehyde from killing GFP fluorescence.  In this protocol (which was tested by MM on 5/19/16 see ntbk #8, p15) 32% paraformaldehyde was used instead of 40% formadelhyde. I (Megan) don't actually think that this makes a big difference and in the past we have found that formaldehyde actually works better.
 
'''*[[User:Megan N McClean|Megan N McClean]] 15:08, 25 July 2013 (EDT)''' We found empirically that removing the formaldehyde is very important for preserving GFP fluorescence.  Don't incubate cells with formaldehyde for more than 20 minutes.
 
'''*[[User:Megan N McClean|Megan N McClean]]''' I have also used the Koshland Lab protocol ([http://mcb.berkeley.edu/labs/koshland/Protocols/MICROSCOPY/gfpfix.html GFP Fixation]) and found that it works approximately as well as this protocol.


==References==
==References==

Latest revision as of 15:02, 27 May 2016


Overview

This is an adaptation of the protocol used by Anjali Bisaria for rapidly fixing yeast cells from chemostat cultures to image for both bud index as well as fluorescence. This protocol has been tested by Megan McClean to preserve GFP fluorescence.

Materials

Protocol

  • Prepare eppendorf tubes with 50μL of 32% paraformaldehyde, one per sample.
  • Add 450μL of culture to 50μL of paraformaldehyde in an eppendorf tube and mix by inversion. (The goal is to have a final concentration of formaldehyde around 3.2%. So you can adjust the cell and paraformaldehyde volumes accordingly, as long as you end up with 3.2% paraformaldehyde).
  • Incubate the tube at room temperature for 15 minutes.
  • Spin down gently for 5 minutes at 8000rpm in the small eppendorf centrifuge.
  • Resuspend cells gently in 250μL of 0.1M potassium phosphate to wash any excess paraformaldehyde.
  • Spin down cells gently for 5 minutes at 8000rpm in the small eppendorf centrifuge.
  • Resuspend cells in 100μL of 0.1M potassium phosphate
  • Store samples at 4°C until you are ready to image.

Notes

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 15:08, 27 May 2016 (EDT) This protocol is adjusted from Anjali's original protocol. Her protocol leaves out the wash step with 0.1M potassium phosphate buffer, which is very important for keeping the formaldehyde from killing GFP fluorescence. In this protocol (which was tested by MM on 5/19/16 see ntbk #8, p15) 32% paraformaldehyde was used instead of 40% formadelhyde. I (Megan) don't actually think that this makes a big difference and in the past we have found that formaldehyde actually works better.

References

Anjali Bisaria, Senior Thesis, 2012

Contact

Megan N McClean 3:12, 25 July 2013 (EDT)

or instead, discuss this protocol.