title: Hydra molecular network reaches criticality at the symmetry-breaking axis-defining moment.
abstract: We study biological, multicellular symmetry breaking on a hollow cell sphere as it occurs during hydra regeneration from a random cell aggregate. We show that even a weak temperature gradient directs the axis of the regenerating animal--but only if it is applied during the symmetry-breaking moment. We observe that the spatial distribution of the early expressed, head-specific gene ks1 has become scale-free and fractal at that point. We suggest the self-organized critical state to reflect long range signaling, which is required for axis definition and arises from cell next-neighbor communication.
authors.affiliation: Experimentalphysik I, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Jordi
authors.initials: J
authors.lastname: Soriano
authors.forename: Cyril
authors.initials: C
authors.lastname: Colombo
authors.forename: Albrecht
authors.initials: A
authors.lastname: Ott
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001696:Biomechanical Phenomena; D019521:Body Patterning / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D006829:Hydra / Q000254:growth & development / Q000502:physiology*; D012038:Regeneration / Q000502:physiology; D013696:Temperature
chemical_list: D015415:Biomarkers