Regeneration in basal Platyhelminthes

Flatworms (Platyhelminthes) show an extraordinary regeneration ability which has been documented for more than 100 years. The most important aspect for regeneration in adult organisms is the likely totipotent stem cell (neoblast) system. The capacity of self renewal and the capacity to differentiate into any cell type are important functional requirements of neoblasts. In this project we want to study and characterize the development of complex microorgans from neoblasts. We will apply ultrastructural, histological and immunocytochemical techniques to follow the fate of neoblasts, and we want to establish 3D-models for developing microorgans. We use two species of basal Platyhelminthes: on one hand the basal rhabditophoran Macrostomum sp. and on the other hand the acoel Convolutriloba longifissura. These animals are especially suited to follow regeneration because of their small size (0.5 to 5 mm) and because of our knowledge on their muscle-, nerve- and stem cell systems from past projects. Furthermore, Convolutriloba longifissura shows asexual reproduction by fission. Thereby we are able to compare natural regeneration of microorgans in these animals with the regeneration after artificial surgery. Moreover, this project should lead to a better understanding of basal processes in the development of muscles and nerves from the neoblast pool. In summary, current problems in the fields of regeneration, stem cells and development of organs will be examined in a basal animal group and conclusions of the mechanisms should allow a better understanding of developmental processes in higher taxa, including the human system.

Flatworms (Platyhelminthes) show an extraordinary regeneration ability which has been documented for more than 100 years. The most important aspect for regeneration in adult organisms is the likely totipotent stem cell (neoblast) system. The capacity of self renewal and the capacity to differentiate into any cell type are important functional requirements of neoblasts. In this project we want to study and characterize the development of complex microorgans from neoblasts. We will apply ultrastructural, histological and immunocytochemical techniques to follow the fate of neoblasts, and we want to establish 3D-models for developing microorgans. We use two species of basal Platyhelminthes: on one hand the basal rhabditophoran Macrostomum sp. and on the other hand the acoel Convolutriloba longifissura. These animals are especially suited to follow regeneration because of their small size (0.5 to 5 mm) and because of our knowledge on their muscle-, nerve- and stem cell systems from past projects. Furthermore, Convolutriloba longifissura shows asexual reproduction by fission. Thereby we are able to compare natural regeneration of microorgans in these animals with the regeneration after artificial surgery. Moreover, this project should lead to a better understanding of basal processes in the development of muscles and nerves from the neoblast pool. In summary, current problems in the fields of regeneration, stem cells and development of organs will be examined in a basal animal group and conclusions of the mechanisms should allow a better understanding of developmental processes in higher taxa, including the human system.