Mesoglein differences between two jellyfish populations of the genus Aurelia

Abstract The medusa, Aurelia aurita (Scyphozoa, Cnidaria), is counted as a cosmopolitan species with a worldwide distribution in most seas, from the poles to the tropics. Cnidarian is thought to possess two tissue layers: endoderm (gastroderm) and ectoderm, which are separated by huge mesoglea in medusa. The main medusas' morphology is similar in different populations. Previously the new protein "mesoglein" was determined as one of the main components of mesoglea. Deduced amino acid sequence of mesoglein contains Zona Pellucida (ZP) domain. The comparison of mesoglein and its gene from three habitats White Sea (WSA), Black Sea (BSA), Japonic Sea (JSA) has been done in the current work. The set of the mesoglea protein bands after SDS-PAGE is similar in all samples. Nevertheless, JSA mesogleins' M, is 53155 kDa, while WsA and BsA mesogleins have M, of 47 kDa. Antibodies raised against WSA mesoglein recognize only mesoglein with M, of 47 kDa, but not 53155 kDa, both on immunoblot and immunocytochemistry. Mesogleal cells and “elastic” fibrils are stained intensively in the mesoglea both from WsA and BsA but not from JSA. The possibility of gene diversity was checked by PCR with primers specific for WsA mesoglein gene. PCR products of expected length were obtained on cDNA from polyA-RNA template from mesogleal cells of WsA and BsA medusa but not on cDNA of JSA medusa. Our results evidence that there are two different species in genus Aurelia: Aurelia aurita inhabits White and Black Seas while Aurelia sp.1 inhabits Japonic Sea. Such a suggestion is in agreement with the one previously done on the base of comparison by other molecular biology methods.