Cell OD and spec problems - (Aug/03/2010 )
So I am working on bacterial growth curves and have run into a bit of a snag. On my last one, which was E. coli, about half way through the curve the readings started going above 1. They never got above 2 but it's still not good. Now the curve plotted with the readings looks like a normal growth curve. However, I understand the need to dilute the samples to so the readings come back down below 1.
My problem lies in how to do the dilution since I need to put the spec sample back into the culture so we can keep the volume the same throughout the procedure so I need to add relatively negligible amounts (the stock is 50ml). Should I do 1:10 or 1:100 dilutions? Also how can the new readings, which are going to be under 1.0 be used to make a growth curve of Abs. vs Time? Thanks.
Nevermind. I finally remembered dilution factors and slapped myself in the head. A simple 1:10 dilution using about 200 microliters won't detract any significant amount of volume from my sample.