Functional morphology of blood erythroid cells in Neogobius melanostomus P. during cell differentiation

Abstract

The morphometric characteristics of the following 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 dimensions of the blood cells were evaluated on photographs in a computer program ImageJ 1.44p. The longitudinal and transverse axes of the cell and its nucleus were measured. Using appropriate algorithms, the following parameters were calculated: shape index (SI), volume (V_c), area (S_c), thickness (h), and specific surface area (SS_c) of cells and nuclei as well as the nuclear–cytoplasmic ratio (NCR). Major changes were found to occur at the stage of PN → normocytes, being aimed at improving the respiratory characteristics of cells. In addition to accumulating hemoglobin in the cytoplasm and suppressing functional activity of the nucleus, a significant increment in the diffusion surface of erythroid cells was noted. As compared to BNs, S_c and SS_c of normocytes increased by 40 and 17%, respectively, while the cells assumed an ellipsoid shape. The processes underlying the formation of the mature erythrocyte cytoskeleton are discussed.