Science Shot: The Transformation of a Jellyfish

1-s2.0-S0960982213015224-fx1Moon jellyfish undergo a bizarre transformation during their lifetime. They start out living on the sea floor as polyps—immobile stalks with a tentacle-ringed mouth—but in early spring they bud into segments, with each one becoming a single adult jellyfish (pictured, showing the polyp, top left, transitioning into an adult, bottom center and right). What triggers this unusual change? To answer this question, researchers studied the behavior of the moon jelly (Aurelia aurita) under various temperature shifts. An 8° drop in water temperature (to 10°C), as might be felt over winter, began the change in about 3 weeks. The researchers discovered that the temperature drop causes the jellyfish to secrete large amounts of a special protein, the precursor to a hormone that causes them to metamorphose. The protein acts like a timer, gradually accumulating until a critical concentration is reached, triggering change in the spring. This buildup process enables the jellyfish to distinguish between the onset of winter and normal temperature fluctuations, the team reports online today in Current Biology. Armed with this knowledge, the researchers were able to synthesize the metamorphosis hormone themselves and force the polyp-to-jellyfish transformation in just 48 hours. The findings could help manage local populations of moon jellyfish, large blooms of which clog fishing nets, or worse—as demonstrated by last October’s forced shutdown of the Oskarshamn nuclear power station, in Sweden, following the buildup of jellyfish in the plant’s coolant intake pipes. By inducing blooms early, in winter—when food is scarce—wildlife managers could limit the number of jellyfish in the water.

Current BiologyWe show in the moon jelly Aurelia aurita that the molecular machinery controlling transition of the sessile polyp into a free-swimming jellyfish consists of two parts. One is conserved and relies on retinoic acid signaling. The second, novel part is based on secreted proteins that are strongly upregulated prior to metamorphosis in response to the seasonal temperature changes. One of these proteins functions as a temperature-sensitive “timer” and encodes the precursor of the strobilation hormone of Aurelia. ScienceShot

 

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2014

Review Flachsbart F & TCG Bosch (2014) (in German) FoxO und die Alterung sterblicher und unsterblicher Organismen. BIOspektrum 20, 747-749. DOI 10.1007/s12268-014-0513-3 .pdficon

paper Fraune S, F Anton-Erxleben, R Augustin, S Franzenburg, M Knop, Katja Schröder, D Willoweit-Ohl, and TCG Bosch (2014) Bacteria-bacteria interactions within the microbiota of the ancestral metazoan Hydra contribute to fungal resistance. ISME J, 2014 Dec 16. doi: 10.1038/ismej.2014.239. [Epub ahead of print] pdficon

paper Grasis JA, Lachnit T, Anton-Erxleben F, Lim YW, Schmieder R, Fraune S, Franzenburg S, Insua S, Machado G, Haynes M, Little M, Kimble R, Rosenstiel P, Rohwer FL, Bosch TCG (2014) Species-specific viromes in the ancestral holobiont hydra. PLoS One 9(10):e109952.pdficon

paper Bosch TCG, M Adamska, R Augustin, T Domazet-Loso, S Foret, S Fraune, N Funayama, J Grasis, M Hamada, M Hatta, B Hobmayer, K Kawai, A Klimovich, M Manuel, C Shinzato, U Technau, S Yum, and DJ Miller (2014). How do environmental factors influence life cycles and development? An experimental framework for early-diverging metazoans. Bioessays 2014 36(12):1185-94.pdficon

The article is accompanied by a 8 min video clip. The video is hosted on Wiley-Blackwell’s Life Sciences You Tube channel

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ReviewBosch TCG (2014) Rethinking the role of immunity: lessons from Hydra. Trends in Immunology 35 (2014), pp. 495-502 DOI 10.1016/j.it.2014.07.008pdficon

paper Domazet-Lošo T, A Klimovich, B Anokhin, F Anton-Erxleben, M Hamm, C Lange, and TCG Bosch (2014) Naturally occurring tumors in the basal metazoan Hydra.  Nature Communications 5, Article number: 4222 doi:10.1038/ncomms5222 Published 24 June 2014. pdficonSupplementary Information pdficon

paper Fuchs B, W Wang, S Graspeuntner, Y Li, S Insua, EM Herbst, P Dirksen, AM Böhm, G Hemmrich, F Sommer, T Domazet-Loso, U Klostermeier, F Anton-Erxleben, P Rosenstiel, TCG Bosch, and K Khalturin (2014) Regulation of polyp to jellyfish transition in Aurelia aurita. Current Biology, Current Biology 24, 1–11, February 3, 2014 ª2014 Elsevier Ltd All rights reserved http://dx.doi.org/10.1016/j.cub.2013.12.003 pdficon See also Science” News See also Dispatch R159 from Current Biology