Yesterday I posted some pictures of E. coli colony morphologies. This was one of the colonies, but it wasn’t as developed, so today I’m adding the extra day’s growth image.
Looks great! It’s interesting to note that the colonies grown on D2O agar grow out. Instead of getting thick like it normally does, it grows in an outward direction. I guess I would attribute that to the stress induced by being in D2O.
Comparing the results from today to WT E. coli grown on DI media and D2O adapted E. coli grown on D2O media, it seems there is an interesting mix of morphological behavior. The adapted E. coli is very “brainy” and obviously the normal WT is “smooth,” but today’s specimen is in between smooth and brainy. Unfortunately I can’t make out the topographical features because the E. coli (as I mentioned above) is very flat. But the contour is very feature rich.
Here are the results of yesterday’s setup. Here I’m comparing 4 samples:
Wild type (WT) E. coli grown on DI LB agar
WT E. coli grown on D2O LB agar
D2O adapted E. coli grown on DI LB agar
D2O adapted E. coli grown on D2O LB agar
All 4 samples were incubated for the same amount of time, and taken from starter cultures of similar absorbance. The absorbances of the starter cultures are as follows:
Wild type (WT) E. coli grown in DI LB – 0.641
WT E. coli grown in D2O LB – 0.325
D2O adapted E. coli grown in DI LB – 0.489
D2O adapted E. coli grown in D2O LB – 0.112
The D2O adapted E. coli took over the DI LB plate! I’ve re-inoculated those cells from that plate to get a picture that would show a typical colony and compare that morphology to the rest. I’ve also allowed the two D2O media samples to incubate for another 24 hours.
It should also be said that the D2O adapted colonies grown on D2O media look distressed compared to the WT colonies on DI media. But compare the two D2O adapted colonies and it’s tough to discern. Whatever mechanism gives the colonies a distressed appearance on D2O media, seems to be completely uninhibited on DI media. It’s tough to tell if the cells are distressed or just out of control.
Still these results seem pretty comparable to the last time I did these experiments (except using YPD). I’ll update again tomorrow, and insert these results into my dissertation.
Yesterday while writing I realized that the images of the D2O adapted E. coli that I’ve taken were grown on D2O YPD. In an effort to figure out if the morphologies are due to the YPD or the D2O, I’ve decided to redo the experiments on LB agar.
Today I made some D2O and DI LB broth:
1.84g LB in 92ml of D2O
1g LB in 50ml of DI water
Filtered broth for sterilization
Then from there I made some LB agar
40ml of liquid D2O LB with 0.8g of agar (2% agar)
I already have solid LB plates with normal water (commercial).
I then incubated E. coli at 37C in liquid media so that I can streak the plates and analyze them. I used 2 different E. coli:
I made this figure for my rockethub proposal and forgot to post it here in my notebook. Look how pretty it is!
I made this in Adobe Illustrator and if anyone is interested I would be willing to host an online workshop to teach others how to use Illustrator for science. This particular image took almost no time (maybe 30 minutes), which is a marvel because I obsess over everything I do in Illustrator (which is why there isn’t anything tangibly Illustrator on this site).