Dinoflagellates-cnidarian symbiosis in an upside down jellyfish – Cassiopea xamachana: Or “how to do science at a poster session and find a real life popeye”

I had the incredible fortune to meet a phenomenal postdoc Dr A. Ohdera at the lab of Dr. Y.Zheng (Carnegie institute, Baltimore) at ASCB (American Society of Cell Biology) 2018 meeting (poster number B786). Amongst thousands of posters – what struck me is that Dr Ohdera – who studies a unique symbiotic relationship between a swimming jellyfish and dinoflagellates – was that he had a baby jellyfish live stuck at the poster.

What a brilliant idea – for many of us who love the beauty of just watching and admiring live animals – it’s something indescribable.

So I stopped, and we talked at length about this beautiful dinoflagellates symbiosis he is working on – and I just casually said – I want to see these dinoflagellates. We both looked at each other; and soon I had my foldscope kit out and I was surgically removing a very small tentacle out of the jellyfish.

I quickly made a slide and 2 minutes later we were watching the tiny dinoflagellates inside the live tissue of the jellyfish.

To me, it was most joyful to see the smile on Ohdera’s face: since he was not expecting to see his own dinoflagellates outside the context of the lab.

What’s beautiful is that the jellyfish does not need to really catch prey – since all the photosynthatse and other products made by dinoflagellates can just be used by the jelly fish. These poor Dino’s are actually prisoners of single cells. The cells divide – share the Dino (that also divide inside the cell) and hence passed through this centipede lineages.

This is as if you could steal spinach cells – get them inside you – and you never have to eat again as long as you hang out in the sun. Isn’t that the story of Popeye! All the super hero’s – we have them in biology.

Next time you present a poster at a conference – remember to bring your foldscope and your organism. I can not think of a better way to connect with the community – you are trying to share your science.

After this experience – we continued to talk about the bizarre biology of this system. If Dr Ohdera succeeds in understanding this system – the ideas would apply for coral reefs since the coral also have dinoflagellates as symbiotic organisms in the tissue. With the dramatic decline of coral reefs due to bleaching (when the dinoflagellates die or leave – and hence the coral dies) – time is running out. Let’s get out and try to understand this crucial “friendship” that makes all our coral reefs work.

So wonderful to meet you my friend!

Keep exploring


3 Comments Add yours

  1. Hey Manu,
    Fantastic post… Thanks for sharing…
    Jellyfishes are really mysterious, they don’t even have a brain and yet they survive, most of the deep sea creatures do for a fact…
    Many theorists believe they’re most likely to be of alien origin.
    Demystifying the ocean creatures can tell us a lot of history and origin of life on our blue planet….
    After all life started in the oceans….
    FYI…There’s one more type of jellyfish known as the immortal jellyfish.
    They can go from old age to juvenile form.


  2. laksiyer says:

    Great idea for a poster indeed. Any videos of the dinoflagellates?

  3. Manu Prakash says:

    The Dino’s were non motile – so I just took pictures. But this is a beautiful system – and these jellyfish are not so hard to keep (they are photosynthetic after all).


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