Sipunculus nudus:Particulate components of the coelomic fluid and its relationship with brown bodies

Abstract

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.KEY WORDS: Sipunculus nudus -Coelomic fluid particulate material -Cellular ageing and brown bodies.

Size-associated Variation and Factors Affecting the Morphology of Brown Bodies in Glycera tridactyla (Polychaeta:Glyceridae)

“…As a consequence, brown bodies are structures associated with the defense mechanism of the host in the coelomic cavity as reported by Lunetta et al (2004). The body surface is also used to absorb and to exchange energy and mass with the external environment to discharge a variety of metabolic products (Niklas 2000) and the smaller cells increase the surface area/volume ratio for an efficient diffusion (Young 2006).…”