State of Drosophila melanogaster Ovaries after a Full Cycle of Gametogenesis under Microgravity Modeling: Cellular Respiration and the Content of Cytoskeletal Proteins.

Maria A Usik,Irina V Ogneva,Maria A Golubkova

doi:10.3390/ijms22179234

Abstract

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.

Highlights

From the perspective of increasing the duration of space flights, questions have arisen concerning the need to maintain reproductive health
After exposure to simulated microgravity during the full cycle of gametogenesis, the rate of oxygen uptake by permeabilized ovaries, V0, increased by 293% (p < 0.05); after the addition of substrates of the first complex of the respiratory chain, the respiration rate, Vglu+mal, was 98% higher (p < 0.05) than that of the control group, and the maximum respiratory rate, Vmax, upon the addition of ADP increased by 64% (p < 0.05)
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Summary

Introduction

From the perspective of increasing the duration of space flights, questions have arisen concerning the need to maintain reproductive health. There are gaps in understanding the effect of real microgravity on the function of the reproductive system. There are a number of difficulties in studying the reproduction process during space flight, in connection with which research with the use of model experiments, including those on animals, is required. Data for different species are scarce; it is known that under space flight conditions, there is a possibility of obtaining offspring from the fruit fly Drosophila melanogaster, Medaka fish, and the amphibian Pleurodeles waltl. It was not possible to obtain pregnancy in mammals, since there were difficulties with fertilization and embryo development in the early stages of embryogenesis [5,6]

Methods

Results

Discussion

Conclusion