Helvik Jon Vidar, Oppen-Berntsen Dag Oscar, Flood Per Robert, Walther Bernt Theodor
Department of Biochemistry, University of Bergen, Årstadveien 19, N-5009, Bergen, Norway.
Department of Anatomy, University of Bergen, Årstadveien 19, N-5009, Bergen, Norway.
Rouxs Arch Dev Biol. 1991 Sep;200(4):180-187. doi: 10.1007/BF00361335.
The halibut hatching gland (HG) cells are first observed as a cellular disc in front of the embryonic head around the midpoint of intra ovo development. The disc is subsequently transformed into a loop of increasing diameter as the HG cells migrate over the anterior part of the yolk sac. When the HG disc is transformed into a loop, the density of HG cells is highest at the migratory front. Some HG cells lag behind the migrating front at the early stages of HG development. At maturity, all cells are contained in a narrow belt which is about 10 cells wide. The HG belt structure consists of a monolayer of HG cells, and is maintained while the cells migrate between the two epidermal cell layers. Migration is halted about 2 days before normal hatching when the HG cells reach a destination at about a right angle to on the embryonic axis. Under the scanning electron microscope, the differentiating HG cells protrude as a ridge the yolk sac surface. The HG cells immunostain with antiserum to hatching enzyme when the HG is observed as a crescent structure around the embryonic head. By counting the number of immunostaining cells in composite photos of the entire yolk sac membrane, we found that the HG belt consists of approximately 2000 secretory cells at maturity. This cell number stays fairly constant throughout the period of HG cell migration. Accordingly, mitoses of the halibut HG cells have generally ceased prior to morphogenesis, and cytodifferentiation is already quite advanced when cell migration starts.
大比目鱼孵化腺（HG）细胞最初在卵内发育中点左右胚胎头部前方以细胞盘的形式出现。随着HG细胞在卵黄囊前部迁移，该盘随后转变为直径不断增大的环。当HG盘转变为环时，HG细胞密度在迁移前沿最高。在HG发育早期，一些HG细胞落后于迁移前沿。成熟时，所有细胞都包含在一条约10个细胞宽的窄带中。HG带结构由单层HG细胞组成，并且在细胞在两个表皮细胞层之间迁移时保持不变。当HG细胞到达与胚胎轴成直角的目的地时，迁移在正常孵化前约2天停止。在扫描电子显微镜下，正在分化的HG细胞在卵黄囊表面突出形成一条脊。当HG在胚胎头部周围呈新月形结构时，HG细胞用孵化酶抗血清进行免疫染色。通过计算整个卵黄囊膜复合照片中免疫染色细胞的数量，我们发现成熟时HG带由大约2000个分泌细胞组成。在HG细胞迁移期间，这个细胞数量相当稳定。因此，大比目鱼HG细胞的有丝分裂通常在形态发生之前就停止了，并且当细胞迁移开始时，细胞分化已经相当成熟。
