HydroxyUrea in yeast cells protocol

http://fg.cns.utexas.edu/fg/protocol__cell_synchrony.html (images and detailed notes)

http://torreslab.biology.gatech.edu/wp-content/uploads/2013/02/Budding-Yeast-Cell-Cycle-Arrest-Procedures.htm

Note of caution: 
We have made lab stock (4°C) of hydroxyurea in a 50 mL conical tube.  Per the instructions on the tube, use 5 mL of the stock for a 35 mL culture.  Please be sure to vortex the stock of hydroxyurea before use - it often comes out of solution in storage.  This type of thing should be considered for any chilled solution of this nature