Studying Echinodermata Arm Explant Regeneration Using Echinaster sepositus.

Echinoderms are marine invertebrate deuterostomes known for their amazing regenerative abilities throughout all life stages. Though some species can undergo whole-body regeneration (WBR), others exhibit more restricted regenerative capabilities. Asteroidea (starfish) comprise one of the few echinoderm taxa capable of undergoing WBR.

Regeneration in Stellate Echinoderms: Crinoidea, Asteroidea and Ophiuroidea.

Reparative regeneration is defined as the replacement of lost adult body parts and is a phenomenon widespread yet highly variable among animals. This raises the question of which key cellular and molecular mechanisms have to be implemented in order to efficiently and correctly replace entire body parts in any animal. To address this question, different studies using an integrated cellular and functional genomic approach to study regeneration in stellate echinoderms (crinoids, asteroids and ophiuroids) had been carried out over the last few years.

Fundamental aspects of arm repair phase in two echinoderm models.

Regeneration is a post-embryonic developmental process that ensures complete morphological and functional restoration of lost body parts. The repair phase is a key step for the effectiveness of the subsequent regenerative process: in vertebrates, efficient re-epithelialisation, rapid inflammatory/immune response and post-injury tissue remodelling are fundamental aspects for the success of this phase, their impairment leading to an inhibition or total prevention of regeneration. Among deuterostomes, echinoderms display a unique combination of striking regenerative abilities and diversity of useful experimental models, although still largely unexplored.

An integrated view of asteroid regeneration: tissues, cells and molecules.

The potential for repairing and replacing cells, tissues, organs and body parts is considered a primitive attribute of life shared by all the organisms, even though it may be expressed to a different extent and which is essential for the survival of both individual and whole species. The ability to regenerate is particularly evident and widespread within invertebrates. In spite of the wide availability of experimental models, regeneration has been comprehensively explored in only a few animal systems (i.

Low genetic diversity and recent demographic expansion in the red starfish Echinaster sepositus (Retzius 1816).

Understanding the phylogeography and genetic structure of populations and the processes responsible of patterns therein is crucial for evaluating the vulnerability of marine species and developing management strategies. In this study, we explore how past climatic events and ongoing oceanographic and demographic processes have shaped the genetic structure and diversity of the Atlanto-Mediterranean red starfish Echinaster sepositus. The species is relatively abundant in some areas of the Mediterranean Sea, but some populations have dramatically decreased over recent years due to direct extraction for ornamental aquariums and souvenir industries.

Re-growth, morphogenesis, and differentiation during starfish arm regeneration.

The red starfish Echinaster sepositus is an excellent model for studying arm regeneration processes following traumatic amputation. The initial repair phase was described in a previous paper in terms of the early cicatrisation phenomena, and tissue and cell involvement. In this work, we attempt to provide a further comprehensive description of the later regenerative stages in this species.

Wound repair during arm regeneration in the red starfish Echinaster sepositus.

Starfish can regenerate entire arms following their loss by both autotomic and traumatic amputation. Although the overall regenerative process has been studied several times in different asteroid species, there is still a considerable gap of knowledge as far as the detailed aspects of the repair phase at tissue and cellular level are concerned, particularly in post-traumatic regeneration. The present work is focused on the arm regeneration model in the Mediterranean red starfish Echinaster sepositus; to describe the early cellular mechanisms of arm regeneration following traumatic amputation, different microscopy techniques were employed.

Homeobox genes expressed during echinoderm arm regeneration.

Regeneration in echinoderms has proved to be more amenable to study in the laboratory than the more classical vertebrate models, since the smaller genome size and the absence of multiple orthologs for different genes in echinoderms simplify the analysis of gene function during regeneration. In order to understand the role of homeobox-containing genes during arm regeneration in echinoderms, we isolated the complement of genes belonging to the Hox class that are expressed during this process in two major echinoderm groups: asteroids (Echinaster sepositus and Asterias rubens) and ophiuroids (Amphiura filiformis), both of which show an extraordinary capacity for regeneration. By exploiting the sequence conservation of the homeobox, putative orthologs of several Hox genes belonging to the anterior, medial, and posterior groups were isolated.