[Regeneration of the digestive system in holothurians].

Five variants of regeneration of the digestive system in holothurians are recognized on the basis of original and published data. They depend on presence of organs remains, ability of cells for de-differentiation, damage type, and ontogenetic stage. Regeneration occurs in all cases by means of differentiated cells, no stem cells participation was recorded in any species studied. It is suggested that the entire diversity of recovering reactions observed for the holothurians gut is not an evolutionary innovation in Holothuroidea but evolved on the basis of already existing mechanisms of regeneration and blastogenesis in the ancient echinodermats. Analysis of khown data indicates that holothurians possess two groups of recovering processes, one of which is close to embryonic development and another to blastogenesis by respective mechanisms. This may indicate probable polyphyletic origin of reparative regeneration in Echinodermata.

[Polyclonal antibodies, labeling radial nerve cells of the starfish Asterias amurensis]. / Poliklonal'nye antitela, markiruiushchie kletki radial'nogo nerva morskoi zvezdy Asterias amurensis.

The results of preliminary studies suggest that the cytoskeletal fraction of the radial nerve of the starfish Asterias amurensis contained a 32 kDa protein, which is tissue specific. This protein was isolated from the radial nerve by preparative electrophoresis and used as an antigen for raising polyclonal antibodies. When testing these antibodies on sections of the starfish tissues, it was shown that they interact only with the proteins present in the radial nerve cells. A conclusion was drawn that the raised antibodies may be used as a cell marker when studying regeneration of the nervous system in starfish.

[Yersinia pseudotuberculosis in a model marine ecosystem (experimental research)]. / Yersinia pseudotuberculosis v model'noi morskoi ékosisteme (éksperimental'noe issledovanie).

Materials on the behavior of Y. pseudotuberculosis in the model of marine ecosystem are presented. Y. pseudotuberculosis, both carrying and having lost the virulence plasmid of 45 MD, die in nonsterile sea water, but are capable of prolonged survival in sterile sea water and in the bodies of echinoderms. The death of these bacteria is accelerated in the presence of larvae of echinoderms. In sea water at low temperature Y. pseudotuberculosis maintained their high pathogenicity potential which they use on contact with eukaryotes. Under these conditions Y. pseudotuberculosis preserve their virulence plasmid, thus causing the disease and death of animals.