2017 Fiscal Year Annual Research Report
The neuroethology of feeding in jellyfish
| Project/Area Number |
17F17092
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| Research Institution | Miyagi University of Education |
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Principal Investigator |
出口 竜作 宮城教育大学, 教育学部, 教授 (90302257)
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| Co-Investigator(Kenkyū-buntansha) |
THOMA VLADIMIROS 宮城教育大学, 教育学部, 外国人特別研究員
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| Project Period (FY) |
2017-04-26 – 2019-03-31
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| Keywords | Neurobiology / Cnidarian / Behavior / Jellyfish / Feeding |
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| Outline of Annual Research Achievements |
1.1. Analysis of jellyfish feeding behavior
Feeding is one of the most important behaviors for animal survival. We focused on the feeding behavior of the jellyfish, because these ‘primitive’ animals are some of the earliest ones to evolve neurons. Jellyfish feed by capturing prey with poisonous sting cells. They then transfer it into their mouth and digest it. We used the jellyfish Cladonema to characterize this feeding behavior in detail. Cladonema jellyfish capture their prey with sting cells in their tentacles. After the prey is captured, they bring it closer to their mouth with tentacle movements (retraction and bending). Then the mouth opens and swallows the prey and the tentacle relaxes to the initial position. This sequence is well-organized, as these steps almost always proceed in this fixed sequence, and efficient, with the whole procedure taking under 2 minutes. We also observed that when jellyfish eat enough prey, they stop ingesting food, suggesting that their appetite is regulated by an as yet unknown mechanism.
1.2. Identification of stimuli that trigger jellyfish feeding
To better understand how the different steps of feeding are triggered, we tested several chemicals for their ability to induce feeding-like tentacle movements. We found that several amino acids caused tentacle shortening, similar to the one observed when prey is caught by a tentacle. Thus, Cladonema jellyfish must have chemosensory cells (presumably neurons) that can identify molecules found in prey and quickly trigger feeding responses.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
It's proceeding as planned.
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| Strategy for Future Research Activity |
We plan to: (1) Label neurons involved in feeding by modifying a functional labeling technique initially used in the zebrafish and (2) Identify genes involved in feeding regulation by transcriptomic analysis.
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