Cytoskeleton Structure in Mouse Sperm and Testes After 30 Days of Hindlimb Unloading and 12 Hours of Recovery

Background/Aims: Changes in the external mechanical field result in cytoskeleton reorganization and the formation of adaptive patterns in different types of cells, including somatic cells and sex cells. The aim of this research was to study the protein and mRNA content of cytoskeletal and sperm-specific genes in the sperm and testis cells of mice. Methods: Mice were subjected to 30 days of antiorthostatic suspension to simulate weightlessness, followed by 12 h of recovery, while receiving essential phospholipids at a dosage of 500 mg/kg/day (30HSE and 30HSE+12h groups) or a similar dosage of a placebo (30HS and 30HS+12h groups). Accordingly, reference groups (CE group and C group) were formed. The total number and the percentage of motile spermatozoa were calculated using a Makler chamber. To analyze the number of viable spermatozoa and the permeability of their membranes, eosin staining was used as well as Diff-Quick for a morphological evaluation. Relative protein and mRNA content was estimated in a western blot and quantitative PCR assay, respectively. Results: The relative protein expression levels of actin (beta and gamma) and two alpha-actinin isoforms (1 and 4) remained constant in the sperm of all study groups, except for the 30HS+12h group, where the alpha-actinin-4 level was 13% higher than in the reference group (p < 0.1). In the testis cells, the relative actin isoform content was equivalent to that in the spermatozoa. However, in the testis cells, the ACTN1 mRNA content was 17% higher in the 30HS group than in the C group (p < 0.05), and decreased after 12 h of recovery. In contrast, the ACTN4 mRNA content was 20% lower in the 30HS group than in the reference group (p < 0.05) and increased after the 12-h recovery period. At the same time, in the group administered the essential phospholipids, the relative ACTN1 and ACTN4 mRNA content did not differ from those of the reference group. The relative beta-tubulin content was similar in the reference C group and the reference CE group, which was administered the essential phospholipids. In the 30HS and 30HS+12h groups, the beta-tubulin content decreased by 19% and 22% (p < 0.05), respectively, and they also decreased in the groups administered the essential phospholipids (30HSE and 30HSE+12h groups, by 27% and 33%, respectively, p < 0.05). In the testis tissue, the relative tubulin content did not change in any of the experimental groups. At the same time, the relative mRNA content of the genes encoding the studied cytoskeletal proteins increased, which may indicate the protein content was regulated mainly at the translational level. Conclusion: The spermogram parameters and the content of the sperm-specific proteins and the associated mRNAs revealed a decrease in the number of mature spermatozoa in mice suspended under conditions of weightlessness. Moreover, the decrease was prevented by the administration of essential phospholipids

Mitochondrial Respiration in Drosophila Ovaries after a Full Cycle of Oogenesis under Simulated Microgravity

Studies of the function of the female reproductive system in zero gravity are urgent for the future exploration of deep space. Female reproductive cells, oocytes, are rich in mitochondria, which allow oocytes to produce embryos. The rate of cellular respiration was determined to assess the functional state of the mitochondrial apparatus in Drosophila melanogaster ovaries in which the full cycle of oogenesis took place under simulated microgravity. Since cellular respiration depends on the state of the cytoskeleton, the contents of the main cytoskeletal proteins were determined by Western blotting. To modulate the structure of the cytoskeleton, essential phospholipids were administered per os at a dosage of 500 mg/kg in medium. The results of this study show that after a full cycle of oogenesis under simulated microgravity, the rate of cellular respiration in the fruit fly ovaries increases, apparently due to complex II of the respiratory chain. At the same time, we did not find any changes in the area of oocytes or in the content of proteins in the respiratory chain. However, changes were found in the relative contents of proteins of the actin cytoskeleton. There were no changes of essential phospholipids and no increase in the rate of cellular respiration of the ovaries after exposure to simulated microgravity. However, in the control, the administration of essential phospholipids led to a decrease in the efficiency of oxygen consumption in the flies’ ovaries due to complexes IV–V

Drosophila melanogaster Sperm under Simulated Microgravity and a Hypomagnetic Field: Motility and Cell Respiration

The role of the Earth’s gravitational and magnetic fields in the evolution and maintenance of normal processes of various animal species remains unclear. The aim of this work was to determine the effect of simulated microgravity and hypomagnetic conditions for 1, 3, and 6 h on the sperm motility of the fruit fly Drosophila melanogaster. In addition to the usual diet, the groups were administered oral essential phospholipids at a dosage of 500 mg/kg in medium. The speed of the sperm tails was determined by video recording and analysis of the obtained video files, protein content by western blotting, and cell respiration by polarography. The results indicated an increase in the speed of movement of the sperm tails after 6 h in simulated microgravity. The levels of proteins that form the axoneme of the sperm tail did not change, but cellular respiration was altered. A similar effect occurred with the administration of essential phospholipids. These results may be due to a change in the level of phosphorylation of motor proteins. Exposure to hypomagnetic conditions led to a decrease in motility after 6 h against a background of a decrease in the rate of cellular respiration due to complex I of the respiratory chain. This effect was not observed in the flies that received essential phospholipids. However, after 1 h under hypomagnetic conditions, the rate of cellular respiration also increased due to complex I, including that in the sperm of flies receiving essential phospholipids

Transmission of Light in Deep Sea Water at the Site of the ANTARES Neutrino Telescope

The ANTARES neutrino telescope is a large photomultiplier array designed to detect neutrino-induced upward-going muons by their Cherenkov radiation. Understanding the absorption and scattering of light in the deep Mediterranean is fundamental to optimising the design and performance of the detector. This paper presents measurements of blue and UV light transmission at the ANTARES site taken between 1997 and 2000. The derived values for the scattering length and the angular distribution of particulate scattering were found to be highly correlated, and results are therefore presented in terms of an absorption length;,ab, and an effective scattering length lambda(sct)(eff). The values for blue (UV) light are found to be lambda(abs) similar or equal to 60(26) m, lambda(sct)(eff similar or equal to) 265(122) m, with significant (similar to15%) time variability. Finally, the results of ANTARES simulations showing the effect of these water properties on the anticipated performance of the detector are presented