Measuring growth of yeast by spotting serial dilutions of liquid cultures Set up 4 microfuge tubes per culture each containing 900 ul sterile water. Add 100 ul of yeast culture* to tube 1, close top and vortex to mix. Remove 100 ul of diluted culture from tube 1 and add to tube 2; mix. Continue serial dilutions out to tube 4. Spot 10 ul of each dilution in a row onto agar plates; allow to dry and incubate 30 C for 1-3 days This plate shows growth of serial dilutions of 6 different yeast cultures (only 3 dilutions for each in this case). One could calculate the cell concentration using these results by counting the colonies in the lowest dilution and then multiply by the dilution factor. *When testing yeast two-hybrid strains containing both the bait and prey plasmids, grow strain in SCD-leutrp media to saturation. Spot diluted cultures onto both SCD-leu-trp and SCD-leu-trp-his-ade. The latter plates will test for bait/prey interactions.