0000000000763908
AUTHOR
G. D'ancona Lunetta
A light and electron microscope study of spherical structures in the test cells of an ascidianCiona intestinalis L.
Spherical structures in the test cells that surround the embryos of the ascidianCiona intestinalis L. (Tunicata, phylum Chordata) were studied by both light and electron microscope. Our data support the view that these structures are microorganism-like cells living in symbiosis with the test cells. Their possible role is discussed.
Sipunculus nudus: particulate components of the coelomic fluid and its relationship with brown bodies
Corpuscular components of the coelomic fluid were observed in Sipunculus nudus using cytochemical and cytoenzymatic methods. In particular, granulocytes were studied and two different types, based on morphology, chemical composition, and function were distinguished. Cell aggregates, identified as stem cells of type II granulocytes, were also evidenced. Besides, empty vesicles, vesicle fragments, laminar structures and brown bodies were observed. Based on the observation of their structure and ultrastructure, brown bodies were attributed with the function of accumulating foreign material, as well as aged components typical of the coelomic fluid.