Unuma T, Yamamoto T, Akiyama T, Shiraishi M, Ohta H
National Research Institute of Aquaculture, Nansei, Mie 516-0193, Japan.
J Exp Biol. 2003 Jan;206(Pt 2):365-72. doi: 10.1242/jeb.00102.
Both male and female sea urchins accumulate the major yolk protein (MYP; the most abundant yolk granule protein in sea urchin eggs) in the nutritive phagocytes of immature gonads before gametogenesis. In this study, quantitative changes in MYP as well as in other biochemical components in the ovary and testis were examined in the course of gametogenesis in Pseudocentrotus depressus. Before gametogenesis, both the ovary and testis contained large quantities of proteins, lipids and polysaccharides. MYP reached about 80% of total protein in both sexes. In the testis, MYP decreased rapidly as spermatogenesis proceeded, and the fully mature testis contained little MYP; the levels of lipids and polysaccharides also decreased. In contrast, the levels of nucleic acids and proteins other than MYP increased markedly. In the ovary, MYP decreased gradually as oogenesis proceeded, and the fully mature ovary contained less than half of the initial amount of MYP. Polysaccharides also decreased, whereas proteins other than MYP increased. These results, taken together with those from other studies, suggest that MYP serves as a protein reserve that accumulates before gametogenesis and is used as material for synthesizing new substances constituting gametes in both male and female sea urchins.
在配子发生之前，雄性和雌性海胆都会在未成熟性腺的营养吞噬细胞中积累主要卵黄蛋白（MYP；海胆卵中最丰富的卵黄颗粒蛋白）。在本研究中，对虾夷马粪海胆配子发生过程中卵巢和精巢中MYP以及其他生化成分的定量变化进行了检测。在配子发生之前，卵巢和精巢都含有大量的蛋白质、脂质和多糖。MYP在两性中均达到总蛋白的约80%。在精巢中，随着精子发生的进行，MYP迅速减少，完全成熟的精巢中几乎不含MYP；脂质和多糖的水平也降低。相反，核酸和除MYP之外的蛋白质水平显著增加。在卵巢中，随着卵子发生的进行，MYP逐渐减少，完全成熟的卵巢中MYP含量不到初始量的一半。多糖也减少，而除MYP之外的蛋白质增加。这些结果与其他研究的结果一起表明，MYP作为一种蛋白质储备，在配子发生之前积累，并在雄性和雌性海胆中用作合成构成配子的新物质的原料。
