Progress Toward Complete Life-Cycle Culturing of the Endangered Sunflower Star, Pycnopodia helianthoides.

AbstractUntil recently, the sunflower star, Pycnopodia helianthoides, was a dominant and common predator in a wide variety of benthic habitats in the northeast Pacific. Then, in 2013, its populations began to plummet across its entire range as a result of the spread of a phenomenon known as sea star wasting disease, or sea star wasting. Although dozens of sea star species were impacted by this wasting event, P. helianthoides seems to have suffered the greatest losses and is now listed by the International Union for the Conservation of Nature as the first critically endangered sea star. In order to learn more about the life history of this endangered predator and to explore the potential for its restoration, we have initiated a captive rearing program to attempt complete life-cycle (egg-to-egg) culture for P. helianthoides. We report our observations on holding and distinguishing individual adults, reproductive seasonality, larval development, inducers of settlement, and early juvenile growth and feeding. These efforts will promote and help guide conservation interventions to protect remaining populations of this species in the wild and facilitate its ultimate return.

TAp63gamma is required for the late stages of myogenesis.

p53 family members, p63 and p73, play a role in controlling early stage of myogenic differentiation. We demonstrated that TAp63gamma, unlike the other p53 family members, is markedly up-regulated during myogenic differentiation in murine C2C7 cell line. We also found that myotubes formation was inhibited upon TAp63gamma knock-down, as also indicated by atrophyic myotubes and reduction of myoblasts fusion index. Analysis of TAp63gamma-dependend transcripts identified several target genes involved in skeletal muscle contractility energy metabolism, myogenesis and skeletal muscle autocrine signaling. These results indicate that TAp63gamma is a late marker of myogenic differentiation and, by controlling different sub-sets of target genes, it possibly contributes to muscle growth, remodeling, functional differentiation and tissue homeostasis.