[Electron immunocytochemistry of lymphocyte surface immunoglobulins in the bursa of Fabricius in the pre- and early postnatal ontogeny of chickens].

The appearance and localization of surface immunoglobulins on B-lymphocytes of the bursa of Fabricius of developing chick embryos and chicks were studied by immuno-electron-cytochemical peroxidase-antiperoxidase (PAP) method. Ultrastructural characteristics of marked and unmarked lymphocytes of the bursa of Fabricius was shown. The increase in the density of reaction product on PAP-complex in the course of lymphocytes differentiation was established.

[Cyclic nucleotides in the ontogeny of the chick thymus].

The dynamics of cAMP and cGMP content of the thymus homogenate from developing chick embryos and chickens was studied during ante- and postnatal development. Changes in the content of cyclic nucleotides bear an oscillatory pattern. At the early stages of embryogenesis (9 to 11 days of incubation) the content of cyclic nucleotides was low and gradually increased by 13 days of incubation.

[Effect of small doses of gamma radiation on the activity of marker enzymes in the plasma membranes of chick embryo liver].

A study was made of marker enzyme activity in plasma membranes of chick liver during embryogenesis in normal conditions and after exposure to ionizing radiation. It was shown that irradiation with small doses of eggs prior to incubation and of chick embryos during different periods of the prenatal ontogenesis caused essential changes in activity of membrane-bound enzymes of liver plasmolemma. Stimulation with small radiation doses was most effective with preincubation irradiation of eggs and most manifest at later stages of the prenatal ontogenesis.