Science Buddies: "Ask an Expert"

Hi i was just wondering for my project I am determining whether the rhopalia or the sensory organ on the Aurelia Aurita or the Moon Jellyfish controls its regeneration ability. I have been working on this project for the past two years with great success. However the methods I am using involve the removal of bell and the organ completely from the jellyfish which causes great stress to the organism. Now in order to reduce stress I would like to implement an electrical shock to the rhopalia of the organism. There are eight rhopalia around the outer edges of the bell. However the jellyfish needs to be kept underwater at all time therefore if I put a current into it the entire jelly would get shocked. My question is, is it possible to contain the shock to the small rhopalia organ on the outer edges of the bell while the jelly is fully submerged underwater.

Thank You!
Manu Vaish

This url will lead you to a detailed diagram of the jellyfish. http://www.marlin.ac.uk/images/taxonomy ... phozoa.jpg The rhopalia are pointed out there.

Hi Manu Vaish,

I'm not sure how much help I can be on this problem, but here goes. If the entire jelly must stay underwater at all times, it doesn't sound to me like it's feasible to completely localize the shock. I'm guessing the jellies live in salt water, correct? Salty water is highly conductive... fresh water is less conductive and distilled water is even less so. So if the jellies are able to survive in that water for a while, it might be possible to provide somewhat more localized shocks. However, it might be inadvisable to put the jellies in fresh water, and doing so might cause extra stress in addition to the stress of the shocks. If your main concern is to minimize the stress of the shock, perhaps you should just lower the strength of the shock.

In addition, experiments that involve applying shocks to live animals may require extra ethics permissions, so make sure you check on that before you get started.

Hope that helps!
Tricia

Hi Tricia,

Thanks for the response! Well what I am trying to do is reduce the stress its receiving from my current methods which is basically dissecting the rhopalia out with a sharp needle by implementing a slight electrical shock.

In terms of extra ethics papers my mentor and teacher have told me that when it comes to invertebrates it doesn't matter. Also all of the jellies that I am using are destined to be used as food for other animals.

Thanks I'll consult with my mentor to see if its possible to put them in fresh water.

Thank You
Manu Vaish