24 hour growth of e. coli in DDW and D2O

2012-04-26T21:52:18Z (GMT) by Anthony Salvagno
<p>Here is some growth data. The cells were incubated at 37C for 24 hours in two batches. One sample was incubated in LB broth dissolved in deuterium depleted water, the other sample was incubated in LB broth dissolved in deuterium oxide (heavy water, D2O). Measurements were recorded via a Thermo Nanodrop. The setup is linked below.</p> <p>The data file includes a bunch of different readings, and the measurements that should be analyzed are in the A600 column. I did an initial blank reading with LB media in DI water. I then measured "blanks" of LB in DDW, 99% D2O, 30% D2O, and 60% D2O. The absorption readings for 30% D2O and DDW were pretty comparable (but less than the initial reading for DI water, hence the negative numbers).</p> <p>Next I blanked the machine with DDW LB media, and measured the absorption. Finally I blanked the machine again with 30% D2O LB media, and measured the 30% D2O culture growth.</p> <p>It is interesting to note that the absorption at 600nm in the D2O sample is a little more than 50% of the absorption in the DDW sample.</p> <p>The data from yesterday (linked below) shows that over 5 hours cells grown in 30% D2O reach a peak at around 0.750 (arbitrary units) and actually decline. I'm not sure if this is the case here but the results of this experiment after 24 hours seems to be consistent with those results. </p>