Ueki Tatsuya, Koike Kanae, Fukuba Ikuko, Yamaguchi Nobuo
1 Department of Biological Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-hiroshima, Hiroshima 739-8526, Japan.
2 Natural Science Center for Basic Research and Development, Hiroshima University, 1-4-2 Kagamiyama, Higashi-hiroshima, Hiroshima 739-8521, Japan.
Zoolog Sci. 2018 Dec 4;35(6):535-547. doi: 10.2108/zs180051.
Most ascidian species settle on underwater substrates during a short free-swimming tadpole larval period. During this process, "rapid adhesion" occurs on adhesive papillae located at the anterior region of the cephalenteron. Settled and transformed ascidians subsequently expand the attachment area by "slow adhesion" with ampullae. In the present study, we attempted to identify the ultrastructures related to the adhesion process and adhesive materials in the ascidian tunic and to elucidate the biological function of vanadium in adhesion. We focused on an adhesive organ named the adhesive projection, which is newly generated by the adhered tunic to enlarge the bonding area between ascidian and substrate. Based on its structure and the presence of vanadiumcontaining blood cells, the adhesive projection was considered to be a large tunic vessel. At the adhered tunic, eosinophilic regions and migrated tunic cells were observed, but metal deposition was not detected. We speculate that the eosinophilic materials were components of the adhesive glue, and these are likey produced in epithelial cells, tunic cells, or both. Furthermore, using imaging mass spectrometry, we identified eight tunic-specific molecules as glue candidates.
大多数海鞘物种在短暂的自由游动蝌蚪幼虫期附着在水下基质上。在此过程中，位于头肠前部的粘附乳头会发生“快速粘附”。附着并变态后的海鞘随后通过壶腹进行“缓慢粘附”来扩大附着面积。在本研究中，我们试图确定与海鞘被囊粘附过程和粘附材料相关的超微结构，并阐明钒在粘附中的生物学功能。我们关注一种名为粘附突起的粘附器官，它是由附着的被囊新生成的，用于扩大海鞘与基质之间的结合面积。基于其结构和含钒血细胞的存在，粘附突起被认为是一个大的被囊血管。在附着的被囊处，观察到嗜酸性区域和迁移的被囊细胞，但未检测到金属沉积。我们推测嗜酸性物质是粘附胶水的成分，这些物质可能由上皮细胞、被囊细胞或两者产生。此外，通过成像质谱分析，我们鉴定出八种被囊特异性分子作为胶水候选物。
