Figure 6

Based on the results obtained in the present study is proposed a scheme to show how hard is the octopus embryo life. ROS generated in the female are partly transferred to the egg during the metabolic processes of ovarian maturation. In the yolk, in addition to the ROS (identified as lipoperoxidation: LPO; protein oxidized: PO), the female placed GSH molecules into the yolk, presumably using yolk vesicles⁵⁸, directly giving the embryo one of the key molecules of the glutathione system, which will allow the neutralization of LPO and other ROS placed by the female in the yolk. The results suggest that this GSH package facilitates the activation of the glutathione system which should increase during embryo development, following the increment of metabolic rate and the ANTIOX mechanisms. The genetic machinery is activated in the embryo in the blastulation phase, provoking an increment in mn-SOD, cu-SOD, and CAT expression recorded during organogenesis, indicating an increase in ANTIOX defense components and their activities in that phase of development. At the same time, HIF-1 also registered an increment in expression, suggesting increments in lipoprotein and carbohydrate metabolism. While CAT and mn-SOD reach their maximum expression in the activation phase and are still stable during the embryo's growth, at the same time, a reduction in the expression of cu-SOD was recorded, suggesting that the cytoplasmic cu-SOD role is finished at the end of the growth phase. The HIF-1 expression was still almost constant during embryo development, indicating its role as a regulator of glucose transporter 1 (GLUT-1) and the most glycolytic enzymes linked to anaerobic metabolism. The relative stability of HIF-1 suggests that embryos experience some level of hypoxia during development, which could be related to the reduction in thermal metabolic scope observed towards the end of embryo development.