title: Induction of reverse development in two marine Hydrozoans.
abstract: Cnidarians are unique organisms in the animal kingdom because of their unequalled potential to undergo reverse development (RD). The life cycle of some species can temporarily shift ordinary, downstream development from zygote to adult into the opposite ontogenetic direction by back-transformation of some life stages. The potential for RD in cnidarians offers the possibility to investigate how integrative signalling networks operate to control directionality of ontogeny (reverse vs. normal development). Striking examples are found in some hydrozoans, where RD of medusa bud or liberated medusa stages leads to rejuvenation of the post-larval polyp stage. Artificial stress may determine ontogeny reversal. We describe here the results of experimental assays on artificial induction of RD by different chemical and physical inducers on two marine hydrozoans, Turritopsis dohrnii and Hydractinia carnea, showing a different potential for RD. A cascade of morphogenetic events occurs during RD by molecular mechanisms and cellular patterns recalling larval metamorphosis. For the first time, we show here that exposure to cesium chloride (CsCl), an inducer of larval metamorphosis, may also induce RD, highlighting similarities and differences between these two master ontogenetic processes in cnidarians.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Universit di Lecce, Italy. jschmich@web.de
authors.forename: Jurgen
authors.initials: J
authors.lastname: Schmich
authors.forename: Yulia
authors.initials: Y
authors.lastname: Kraus
authors.forename: Doris
authors.initials: D
authors.lastname: De Vito
authors.forename: Daria
authors.initials: D
authors.lastname: Graziussi
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Boero
authors.forename: Stefano
authors.initials: S
authors.lastname: Piraino
mesh_terms: D000818:Animals; D002586:Cesium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D037402:Hydrozoa / Q000254:growth & development*; D008018:Life Cycle Stages / Q000187:drug effects; D008675:Metamorphosis, Biological; D015398:Signal Transduction
chemical_list: D002712:Chlorides; D002586:Cesium; C028019:cesium chloride