POSSIBLE OCCURRENCE OF AMITOTIC CELL-DIVISION DURING HEMATOPOIESIS INTHE URODELES

The liver haemopoietic activity of three species of Urodeles (Triturus carnifex, Triturus alpestris and Speleomantes ambrosii) was examined by morphocytochemical approaches (light and electron microanti-BrdU im munocytochemistry, flow cytometry). The proliferation of haemopoietic cells, detected the anti-BrdU labelling index. was accompanied by abse nce of mitotic cell division and the appearance of cells showing featu res of amitosis (e.g. nuclear constrictions with bundles of electron-d ense chromatin) sometime positive to the anti-BrdU immune-gold reactio n. The possible unbalanced segregation of chromatin during the direct division of the nucleus was detected by flow cytometric measurement in terms of heterogeneous relative DNA content in peripheral blood cells . The presence in the bloodstream samples of cells (erythrocytes) with replicating DNA, nuclear constrictions and binucleations is also cons istent with a situation of direct nuclear division.