The sponge Chondrosia reniformis selectively engulfs siliceous particles that, when in crystalline form, become quickly dissolved in its ectosome
. The molecular mechanism, identity, and physiological significance of the cells involved in this process are not completely understood.
Exosome Microvesicle, ectosome
, shedding vesicles Size 40-100 nm 100-1000 nm Markers CD63, CD9, Alix, Anexin V, Flotillin-2, TSG 101, HSP 70 selectin, integrin, CD40 metalloproteinase Isolation Immunoprecipitation Ultracentrifugation method (ExoQuick[R]) (10,000-60,000 g) ultracentrifugation (100,000-200,000 g), ultracentrifugation with density gradient References 49,53 54 Apoptotic bodies Size 1000-5000 nm Markers Anexin V, DNA, histones Isolation No standardized protocol method References 55
Areas of Cacospongia underneath Dysidea were often necrotic, clearly recognized by a loss of the ectosome
, revealing the underlying tan-colored portion of the sponge.
All of the oscula in a confluent individual of the unusual form may be completely closed when the sponge is disturbed (e.g., by sediment deposited after a storm, or a large ophiuroid crawling over the sponge), because the rim collapses, along with the thin ectosome
covering the surface canals, during lulls in pumping (Fig.
A section through the sponge reveals two distinct regions: a cortical zone called ectosome
, and an internal zone, the choanosome, which contains the choanocyte chambers.
In addition, ectosomes
, apoptotic bodies (ABs), and large oncosomes (LO) represent additional subpopulations of EVs, which shared the feature to be secreted by budding from the cell plasma membrane (PM) and may express quantitatively and/ or qualitatively different types of molecular components [32-35].
Neutrophils secrete their products via a variety of the mechanisms, including fusion of secretory granules with the plasma membrane  and shedding of membrane vesicles (ectosomes
) from the plasma membrane [35-39].
They are usually classified into three groups: microvesicles (MVs) (also known as ectosomes
or microparticles), exosomes, and apoptotic bodies, depending on their size, morphology, density, and biogenetic origin .
) shed by stored human platelets downregulate macrophages and modify the development of dendritic cells.
DPP4 is also present in plasma as a soluble form, which either comes from a shedding process driven by proteinases or is released into circulation by means of vesicles such as exosomes, ectosomes
, and apoptotic bodies.