Video 1

Spontaneous body contractions of Hydra (65x acceleration). The spontaneous contractions are shrinkages of the body column that occur periodically in the absence of any exogenous stimuli.

Reference: Murillo-Rincon, A.P., Klimovich, A., Pemöller, E. et al. Spontaneous body contractions are modulated by the microbiome of Hydra. Sci Rep 7, 15937 (2017) doi:10.1038/s41598-017-16191-x

Video 3

In vivo imaging of neuronal activity in the hypostome of Hydra. The method of generating transgenic Hydra strains that express genetically encoded Ca2+-sensitive fluorescent proteins (GCaMP) in specific neuronal populations is established in the Bosch lab in Kiel. Here, the activity of the neuronal population N6 is induced by addition of reduced glutathione (GSH).

Credits: Christoph Giez / CAU Kiel

Video 5

Quantitative analysis of Hydra spontaneous contractile behavior. The animation explains the automatized video-recording of a freely behaving polyp and further analysis of the image sequence using a custom script to generate such metrics of the behavior as stretching and contractile capacity, contraction frequency and regularity.

Reference: Murillo-Rincon, A.P., Klimovich, A., Pemöller, E. et al. Spontaneous body contractions are modulated by the microbiome of Hydra. Sci Rep 7, 15937 (2017) doi:10.1038/s41598-017-16191-x