71.1 Saturday, Jan. 5 Examining a cnidarian novelty: form and function of the nematosomes in Nematostella vectensis BABONIS, L.S.*; MARTINDALE, M.Q.; Kewalo Marine Lab, Univ of Hawaii; Kewalo Marine Lab, Univ of Hawaii email@example.com
Sea anemones in the genus Nematostella are unique among cnidarians in their possession of autonomous, motile, cell masses called nematosomes which circulate throughout the body cavity. Although they were first described many decades ago, neither the form nor the function of nematosomes has been studied in great detail. Using a combination of electron microscopy (TEM and SEM) and molecular biology we build on previous studies to describe the cellular composition of the nematosomes from Nematostella vectensis. Although nematosomes are thought to arise from mesenterial tissue, preliminary results suggested that these motile cell masses are composed of several cell types, potentially including cell types found only in the tentacles of N. vectensis. In light of these observations, we compared the cellular composition of nematosomes with that of the mesenteries and isolated tentacles. Using EdU (a BrdU analog), we demonstrate that some nematosomes undergo proliferation while inside the gastric cavity. We use the combined results of these studies to develop hypotheses regarding the origin and function of nematosomes in N. vectensis.