Meeting report on “Animal Evolution: New Perspectives From Early Emerging Metazoans”, Tutzing, September 14–17, 2015

Juliano, Celina E.; Hobmayer, Bert

doi:10.1002/bies.201500200

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…3 hydras developed in direction of the light path, head up, the others developed in different directions (N=9), but within a circular area around the pipette tip (see figure, supplementary). No hydra regenerated with the tentacles facing downwards, pointing either to a sensitivity to gravity, as suggested by H. Shimitzu 29 , or a sensitivity to the red light from a light emitting diode used for illumination. Controls were left to regenerate individually on the bottom of a petri dish, slightly below the location given by the pipette tip.…”

Section: Micropipette Aspirationmentioning

confidence: 88%

Symmetry breaking andde-novoaxis formation inhydraspheroids: the microtubule cytoskeleton as a pivotal element

Sander

Pasula

Sander

et al. 2020

Preprint

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The establishment of polarity in cells and tissues is one of the first steps in multicellular development. The 'eternal embryo' hydra can completely regenerate from a disorganised cell cluster or a small fragment of tissue of about 10, 000 cells. During regeneration, the cells first form a hollow cell spheroid, which then undergoes de-novo symmetry breaking to irreversibly polarise. Here, we address the symmetry-related shape changes. Prior to axis establishment, the spherical aggregates of regenerating cells show highly coordinated mechanical oscillations on several timescales that are isotropic in space. There are transient periods of fluctuations in defined arbitrary directions, until these undergo a clearly identified irreversible transition to directed fluctuations along the future main axis of the regenerating hydra. Stabilised cytosolic actin structures disappear during the de-novo polarisation, while polymerised microtubules remain. Drugs that depolymerise actin filaments accelerate the symmetry breaking process, while drug-stabilised actin filaments prevent it. Nocodazole-depolymerised microtubules prevent symmetry breaking, but it can be rescued by the microtubule-stabilising drug paclitaxel at concentrations where microtubular structures start to reappear. We discuss the possibility that these mechanical fluctuations induce the orientation of the microtubules, which contribute to β -catenin nuclear translocation, to increase the organiserforming-potential of the cells. Our data suggest that in regenerating hydra spheroids, the biomechanical shape fluctuations are an integral part of the cooperative polarisation of the self-organising hydra, during which microtubules play a pivotal role.

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Section: Micropipette Aspirationmentioning

confidence: 88%

Symmetry breaking andde-novoaxis formation inhydraspheroids: the microtubule cytoskeleton as a pivotal element

Sander

Pasula

Sander

et al. 2020

Preprint

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“…Indeed, the first experiments using genetically encoded calcium indicators to monitor organism-wide neural activity are now underway [107] and in conjunction with the use of optogenetics tools (e.g. light controlled ion channels), these will be instrumental in understanding how non-centralized nervous systems generate spontaneous behaviour and react in response to environmental cues.…”

Section: Modern Methods Reach Cnidariamentioning

confidence: 99%

“…While it is impossible to predict how these dynamical landscapes will appear, it is likely that insights acquired in this research could help illuminate a similar research agenda in Bilateria. The initial results in the “brain-wide” imaging of Hydra vulgaris , which displays robust endogenous and sensory-drive dynamics [107], bodes well for the success of such an experimental program.…”

Section: Concluding Remarks and Future Perspectivesmentioning

confidence: 99%

Back to the Basics: Cnidarians Start to Fire

Bosch

Klimovich

Domazet-Lošo

et al. 2017

Trends in Neurosciences

117

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The nervous systems of cnidarians, pre-bilaterian animals that diverged close to the base of the metazoan radiation, are structurally simple and thus have great potential to inform us about basic structural and functional principles of neural circuits. Unfortunately, cnidarians have thus far been relatively intractable to electrophysiological and genetic techniques and consequently have been largely passed over by neurobiologists. However, recent advances in molecular and imaging methods are fueling a renaissance of interest in and research into cnidarians nervous systems. Here, we review current knowledge on the nervous systems of some cnidarian species and propose that researchers should seize this opportunity and undertake the study of this phylum as strategic experimental systems with great basic and translational relevance for neuroscience.

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