无轮幼虫

In this paper, we studied M. meretrix ferritin, cathepsin B and caspase genes, which are involved in clam larval shell formation, nutrition, metabolism and apoptosis, respectively. We have cloned the three genes, investigated the temporal and spatial expression profile both at gene and protein level in trochophore (L1), D-veliger (L2), pediveliger (L3) and postlarvae (L4). The potential roles of these proteins were analyzed with specific inhibitors during larval development. Firstly, embryos were found developed into trochophore-like larvae with no shell if cultured at gastrula stage in artificial seawater without iron. Shell-like structures were formed only in the presence of iron. The larvae which had been transferred at L1 stage into ASW developed normal shell. This indicated that iron and iron associated protein are important for larval shell formation. The EST sequence which is homologous with ferritin, which is a principal iron metabolic protein, was selected from the M. meretrix cDNA library. The full-length of ferritin subunit cDNA was cloned by RACE. The results of real-time PCR revealed that the MmeFer mRNA expression changed before and after the larval shell formation.

本论文以文蛤幼虫为研究对象，分别对文蛤幼虫发育过程中贝壳形成相关的铁蛋白、营养及变态相关的组织蛋白酶B及变态过程中细胞凋亡相关的caspase三个基因进行了克隆，分析了基因及编码蛋白在担轮幼虫期(L1)、D形幼虫期(L2)、壳顶幼虫期(L3)和稚贝期(L4)的时空表达特征，解析了其可能的功能，并研究了相应酶类的特异性抑制剂作用对幼虫发育过程的影响，进行了目标蛋白的功能验证，详述如下：研究结果显示，在文蛤胚胎发育到原肠胚时放入不含铁离子的人工海水中培养，发育成无壳的畸形，随着人工海水中铁离子添加浓度的升高，幼虫长出壳状组织接近正常状态；而发育到L1期幼虫放入不含铁离子的人工海水中培养却可以发育出正常的壳，推测铁和铁代谢相关蛋白在幼虫贝壳初始形成有重要的作用。

The rotation of the drum produces a relative motion between the filtering screen and the surrounding water making the filtering screen self-cleaning. Nauplii and rotifers thus could be concentrated at high speed to a high density with little damage.

滚筒的旋转会在滤网与周围的水体间产生相对运动而使得滤网面自净，丰年虾无节幼虫与轮虫因此可以在高速下被浓缩到高密度而不会有太大的损伤。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。