Administration of Essential Phospholipids Prevents Drosophila Melanogaster Oocytes from Responding to Change in Gravity.

The aim of this study was to prevent initial changes in Drosophila melanogaster oocytes under simulated weightlessness and hypergravity at the 2 g level. Phospholipids with polyunsaturated fatty acids in the tail groups (essential phospholipids) at a concentration of 500 mg/kg of nutrient medium were used as a protective agent. Cell stiffness was determined using atomic force microscopy, the change in the oocytes' area was assessed as a mark of deformation, and the contents of cholesterol and neutral lipids were determined using fluorescence microscopy. The results indicate that the administration of essential phospholipids leads to a decrease in the cholesterol content in the oocytes' membranes by 13% ( p < 0.05). The stiffness of oocytes from flies that received essential phospholipids was 14% higher ( p < 0.05) and did not change during 6 h of simulated weightlessness or hypergravity, and neither did the area, which indicates their resistance to deformation. Moreover, the exposure to simulated weightlessness and hypergravity of oocytes from flies that received a standard nutrient medium led to a more intense loss of cholesterol from cell membranes after 30 min by 13% and 18% ( p < 0.05), respectively, compared to the control, but essential phospholipids prevented this effect.