[FUNCTIONAL MORPHOLOGY OF BLOOD ERYTHROID CELLS IN NEOGOBIUS MELANOSTOMUS P. DURING CELL DIFFERENTIATION].

The morphometric characteristics of immature erythroid cells in circulating blood of the round goby (Neogobius melanostomus P) were studied: late basophilic normoblasts (BN), polychromatic normoblasts (PN), normocytes (mature erythrocytes). The linear sizes of the blood cells were assessed on photographs in the computer program ImageJ 1.44p. The sizes of the longitudinal and transverse axes of the cell and of its nucleus were determined. Using the appropriate algorithm, the following parameters were calculated: form index (MS), volume (Vc), area (Sc), thickness (h) and the specific surface area (SSc) of cells and nuc- lei as well as the nuclear-plasma ratio (NCR). The major changes occurred at the stage: PN - normocy- tes. They were aimed at improving the respiratory characteristics of cells. Besides accumulating hemoglobin in the cytoplasm and suppressing the functional activity of the nucleus, a significant increase in the diffusion surface of blood corpuscles was noted. As compared to BNs, S, and SS, of normocytes increased by 40 and 17 %, respectively, and the cells became ellipse-shaped. The processes underlying the formati- on of mature erythrocyte cytoskeleton are discussed.