Sharanya, Entry #3, Week #4-Glowing Cannibals

This week was definitely a lot smoother than the last one, despite us having our second sampling day and using new machinery in the lab. We were able to efficiently sample and filter sixty-three bottles of cells and prey cultures in six hours and I also learned how to use the FIRe (Fluorescence Induction Relaxation sytem) and the chlorophyll filters. On Monday, my lab partner and I went to check on the progress and growth of the Noctiluca cell cultures in the incubators. Some of the bottles demonstrated what we were expecting while others surprised us. Specifically, we noticed certain bottles like the "Noctiluca+Pyramimonas" under light conditions were lacking prey so this shows that the Noctiluca were indeed feeding on these chlorophytes and may even prefer them to other modes of consumption. Since there was light in the cultures, one would think that the Noctiluca are inclined to photosynthesize but this doesn't seem to be the case in this particular culture. The "Noctiluca+Pyramimonas" in the dark surprised us as well, indicating that the Noctiluca were not feeding as much on the prey but were actually participating in photosynthesis. I have attached an image below to show the comparison between the light, dark, and only-prey cultures. 

A Comparison of the Light, Prey-only, and Dark cultures of N+Pyramimonas (Left to right)

Additionally, I also learned how to use the chlorophyll filters (image directly below) to extract the Noctiluca/prey cultures from the solutions. Basically, I am filtering the cells and other "organic material" onto small, circular, combustible filters and then placing those filters into tubes of acetone. This had to be done in the dark since the photosynthetic cultures are light-sensitive. This would cause the cells to rupture (die) and would give us the inner contents including chlorophyll, ammonia, and endosymbionts. We then removed these filters from the acetone 'culture' and placed the samples into the FIRe. This is probably one of my favorite things that I have done in the lab so far because as I was transferring the cultures onto the filters, I was able to see cells from some of the cultures glow as they made contact with the filters. I tried attached a video of the fluorescence (below the image of the filters), though it's easy to miss unless you focus on the center of the screen.:)

Chlorophyll filter =D

Finally, we also observed that our control cultures, which only contain fifty Noctiluca cells without any prey, were somehow thriving on their own without photosynthesizing. We deduced this because of the lack of chlorophyll and endosymbionts within each individual cell. But somehow they were thriving. I remember my PI saying a few moments later, "I think they are either cannibals or are feeding on their own endosymbionts, since there is no prey and they are not photosynthesizing." This possibility is something that hasn't been discussed within the marine biology community, but we were all definitely excited to have had such profound results.

It's been a great week and I can't believe my time here is almost over! I am looking forward to these next two weeks and will update you all soon!