Moon Jellyfish Lab Report

Report
The Aurelia aurita, also known as moon jellyfish, is a common species of jellyfish, which can be found in oceans around the world. They are hardy, and capable of living in acidic, polluted or poorly oxygenated water. Life Cycle of Moon jellyfish
The polyps are the first stage of their life, hatching from eggs. The polyps undergo a process called strobilation, to enter the strobila stage, and then the juvenile stage, which are called ephyra. They then mature to enter the adult stage, known as medusa, over the period of one month, under laboratory conditions, which include abundant sources of food.

Anatomy of Interest
The ephyra stage of the species, which is the one of interest to this experiment, have a disk shaped body and 8 symmetrical
The experiment was carried out in various conditions, such as stagnant and flowing water, light and dark, as well as jellyfish which were raised alone and those which grew in groups.
Observation
The healing process started within a few minutes, with the wound closing, and the eventual spreading out of arms, which occurred between 12 hours and 4 days. Even when foreign arms were grafted, the extra arm was used to attain symmetry. It was also of note that the final size of the bodies of jellyfish after growth was proportional to the number of arms that it had. It was observed that the process did not change with respect to external conditions, such as light, motion of water which suggests that the symmetrization is purely internal.
Between 72% to 96% of ephyrae underwent the process. The ones that became symmetrical became indistinguishable from those which are not amputated jellyfish and went on to become fully mature, and were observed to be actively swimming, while those that didn’t would grow oversized mouths and undersized bells, and be unable to move off the tank floor.
5- ethynyl-2′-deoxyuridine (EdU) was used as the stain. However, there was no dramatic increase in the size of the stain during symmetrization, proving that theory wrong.
The theory that programmed cell death on the cut side of the void, created a negative pressure to pull the arms to the other side was tested. Sytox, a DNA-binding dye that does not cross intact cell membranes and therefore only stains cells with compromised membranes, indicating cell death, was used. This theory too was proven false.
This seemed to indicate that it was not proliferation or death that caused it but reorganization of the cells. Muscular reconnection on the cut side could pull the arms to the cut side. To block muscle reconnection, we treated the cut ephyrae with cytochalasin D, which inhibits it, after the cuts healed sufficiently. The observation was that the muscle reconnection was inhibited, but a percentage of them continued to undergo the process. However, it was also seen that an increase in concentration of cytochalasin D seemed to decrease the number of symmetric