The effect of weightlessness on gametogenesis and the functional state of female germ cells are still poorly understood. We studied the ovaries of Drosophila melanogaster, the full development cycle of which (from zygote to sexually mature adults) passed under simulated microgravity by a random positioning machine. The rate of cellular respiration was studied by polarography as a parameter reflecting the functional state of mitochondria. The content of cytoskeletal proteins and histones was determined using Western blotting. The relative content of mRNA was determined using qRT-PCR. The results obtained indicated an increase in the rate of cellular respiration under simulated microgravity conditions during the full cycle of gametogenesis in Drosophila melanogaster due to complex I of the respiratory chain. In addition, an increase in the contents of actin cytoskeleton components was observed against the background of an increase in the mRNA content of the cytoskeleton’s encoding genes. Moreover, we observed an increase in the relative content of histone H3 acetylated at Lys9 and Lys27, which may explain the increase in the expression of cytoskeletal genes. In conclusion, the formation of an adaptive pattern of functioning of the Drosophila melanogaster ovaries that developed under simulated microgravity includes structural and functional changes and epigenetic regulation.

No abstract

No abstract

The effect of space flight factors and the subsequent adaptation to the Earth’s gravity on oocytes is still poorly understood. Studies of mammalian oocytes in space present significant technical difficulties; therefore, the fruit fly Drosophila melanogaster is a convenient test subject. In this study, we analyzed the structure of the oocytes of the fruit fly Drosophila melanogaster, the maturation of which took place under space flight conditions (the “Cytomehanarium” experiment on the Russian Segment of the ISS during the ISS-67 expedition). The collection of the oocytes began immediately after landing and continued for 12 h. The flies were then transferred onto fresh agar plates and oocyte collection continued for the subsequent 12 h. The stiffness of oocytes was determined by atomic force microscopy and the content of the cytoskeletal proteins by Western blotting. The results demonstrated a significant decrease in the stiffness of oocytes in the flight group compared to the control (26.5 ± 1.1 pN/nm vs. 31.0 ± 1.8 pN/nm) against the background of a decrease in the content of some cytoskeletal proteins involved in the formation of microtubules and microfilaments. This pattern of oocyte structure leads to the disruption of cytokinesis during the cleavage of early embryos.