ACIDIFICATION OF YOLK GRANULES IN BLATTELLA-GERMANICA EGGS COINCIDENT WITH PROTEOLYTIC PROCESSING OF VITELLIN
ACIDIFICATION OF YOLK GRANULES IN BLATTELLA-GERMANICA EGGS COINCIDENT WITH PROTEOLYTIC PROCESSING OF VITELLIN
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DOI：
10.1002/arch.940180306
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发表时间：
1991-01-01
影响因子：
2.2
通讯作者：
LIU, XD
中科院分区：
文献类型：
--
作者：
NORDIN, JH;BEAUDOIN, EL;LIU, XD
在德国小蠊的卵中，卵黄蛋白(Vt)的利用是在排卵后第4天通过将其三个亚基蛋白分解为一组特定的多肽而启动的。我们实验室的一份报告(Nordin等人：昆虫生物化学和生理学档案15：119,1990)描述了一种在第3-4天激活的卵黄蛋白水解酶，它处理Vt。对这一事件的进一步调查主要集中在蛋黄颗粒上。排卵后4-6天的卵颗粒中含有大量积累高浓度染料吖啶橙(AO)的亚群，而排卵后0-3天的卵颗粒则没有。Ao的积累是由质子转移引起的，而不是由于染料结合或Donnan平衡。颗粒酸化与Vt处理的时间相关性表明，这一事件在德国乳杆菌卵黄蛋白水解酶的激活中发挥了作用。支持这一假说的发现是，在pH为5或更低的条件下，体外孵育新鲜排卵的卵黄会导致Vt加工。苍蝇的卵黄颗粒也会酸化，但这发生在卵沉积之前的卵母细胞中。
In eggs of the cockroach Blattella germanica, vitellin (Vt) utilization by the embryo is initiated at day 4 postovulation by the proteolytic processing of its three subunits to a specific set of peptides. A report from our laboratory (Nordin et al.: Archives of Insect Biochemistry and Physiology 15:119, 1990) described a yolk proteinase, activated at days 3-4, which processes the Vt. Further investigation of this event has focused on the yolk granules. Granules from eggs 4-6 days postovulation contained a significant subpopulation which accumulated high concentrations of the dye acridine orange (AO), a fluorescent probe of vesicle acidification, while those from eggs 0-3 days postovulation did not. AO accumulation was caused by proton translocation and was not due to dye binding or a Donnan equilibrium. The temporal correlation of granule acidification with Vt processing suggests a role for this event in yolk proteinase activation in B. germanica. This hypothesis was supported by the finding that incubation of yolk f rom freshly ovulated eggs in vitro at pH of 5 and below resulted in Vt processsing. Yolk granules of the blowfly Phormia regina also became acidified but this occurred in the oocyte prior to egg deposition.