Press Release: New insights of the gastrovascular system of Rhizostoma pulmo

New insights of the gastrovascular system of a rhyzostoean jellyfish, Rhizostoma pulmo

Fig. Samples of Rhizostoma pulmo
 

Just published in PLOS ONE “A novel endocast technique providing a 3D quantitative analysis of the gastrovascular system in Rhizostoma pulmo: an unexpected through-gut in Cnidaria” with the results of an international research team (Italy, France, Spain, Slovenia) led by the Department of Life Science, University of Trieste (UniTs), in close collaboration with the Elettra synchrotron laboratory in Trieste (Italy) on R. pulmo medusa specimens provided a brand-new and detailed description of the gastrovascular system of a jellyfish by using a completely innovative protocol combining resin endocasts (Figure, left) and laboratory-based X-ray computed microtomography (µCT) (Figure, right).
The whole endocast has been imaged by using the FAITH micro-CT station at Elettra. The 3D data obtained by using the µCT technique allowed to directly visualize and describe in a quantitative fashion the gastrovascular system without specimen sectioning.
 

Lucia Mancini and Marco Voltolini, researchers at Elettra, said “The internal structure of a whole medusa was visualized in 3D and fully characterized for the first time allowing to visualize their volumetric pattern, and this opens new opportunities for a better understanding of the feeding biology of medusae”.

Additionally, since the images are digital data, anyone can access them and use in his own research. “This is a huge upgrade in jellyfish science” said UniTs Professor Massimo Avian and Gregorio Motta, PhD student (UniTs and Stazione Zoologica A. Dohrn, Naples) “since, to date, all studies of jellyfish gastrovascular systems were based on stain injections, drastically affected by thickness and opacity of the mesoglea. This led to incomplete description with no information on the tridimensional structures of these apparatuses. This study shed new light on the through-gut development and evolution. Jellyfish are commonly described to possess a single oral mouth or pore dedicated to both the ingestion and the egestion of food. In R. pulmo, canals presented a double hemi-canal structure with a complete physical separation of the inward/outward currents and a consequent differentiation of the function (ingestion/egestion) of the openings on the oral arms, thus resembling a sort of digestive apparatus analogous to the trough-gut common within bilaterians”. The comprehension of the gastrovascular system and its circulation pattern are very important to understand jellyfish feeding physiology and their role in the trophic webs, even more these days where jellyfish blooms are more and more frequent all over the world.