Indomethacin reproducibly induces metamorphosis in Cassiopea xamachana scyphistomae

Abstract

Cassiopea xamachana jellyfish are an attractive model system to study metamorphosis and/or cnidarian-dinoflagellate symbiosis due to the ease of cultivation of their planula larvae and scyphistomae through their asexual cycle, in which the latter can bud new larvae and continue the cycle without differentiation into ephyrae. Then, a subsequent induction of metamorphosis and full differentiation into ephyrae is believed to occur when the symbionts are acquired by the scyphistomae. Although strobilation induction and differentiation into ephyrae can be accomplished in various ways, a controlled, reproducible metamorphosis induction has not been reported. Such controlled metamorphosis induction is necessary for an ensured synchronicity and reproducibility of biological, biochemical and molecular analyses. For this purpose, we tested if differentiation could be pharmacologically stimulated as in Aurelia aurita, by the metamorphic inducers thyroxine, KI, NaI, lugol's iodine, H 2 O 2 , indomethacin, or retinol. We found reproducibly induced strobilation by 50 µM indomethacin after 6 days of exposure, and 10-25 µM after 7 days. Strobilation under optimal conditions reached 80-100% with subsequent ephyrae release after exposure. Thyroxine yielded inconsistent results as it caused strobilation occasionally, while all other chemicals had no effect. Thus, indomethacin can be used as a convenient tool for assessment of biological phenomena through a controlled metamorphic process in C. xamachana scyphistomae. 1 Indomethacin reproducibly induces metamorphosis in Cassiopea xamachana scyphistomae 2 Abstract 3 Cassiopea xamachana jellyfish are an attractive model system to study metamorphosis and/or 4 cnidarian-dinoflagellate symbiosis due to the ease of cultivation of their planula larvae and 5 scyphistomae through their asexual cycle, in which the latter can bud new larvae and continue 6 the cycle without differentiation into ephyrae. Then, a subsequent induction of metamorphosis 7 and full differentiation into ephyrae is believed to occur when the symbionts are acquired by the 8 scyphistomae. Although strobilation induction and differentiation into ephyrae can be 9 accomplished in various ways, a controlled, reproducible metamorphosis induction has not been 10 reported. Such controlled metamorphosis induction is necessary for an ensured synchronicity and 11 reproducibility of biological, biochemical and molecular analyses. For this purpose, we tested if 12 differentiation could be pharmacologically stimulated as in Aurelia aurita, by the metamorphic 13 inducers thyroxine, KI, NaI, lugol's iodine, H 2 O 2 , indomethacin, or retinol. We found 14 reproducibly induced strobilation by 50 µM indomethacin after 6 days of exposure, and 10-25 15 µM after 7 days. Strobilation under optimal conditions reached 80-100% with subsequent 16 ephyrae release after exposure. Thyroxine yielded inconsistent results as it caused strobilation 17 occasionally, while all other chemicals had no effect. Thus, indomethacin can be used as a 18 convenien...

Host–symbiont plasticity in the upside-down jellyfish Cassiopea xamachana: strobilation across symbiont genera

“…Strobilation in C. xamachana can be induced by a chemical stimulant (Cabrales-Arellano et al, 2017), indicating that once polyps receive the signal for strobilation, the metamorphic pathway will continue independent of colonization by a symbiont. Our results support this with natural symbiont infections; the strobilation cascade proceeds along a designated developmental trajectory.…”