Possible involvement of glycolipids in lectin-mediated cellular transformation of symbiotic microalgae in corals
Possible involvement of glycolipids in lectin-mediated cellular transformation of symbiotic microalgae in corals
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DOI：
10.1016/j.jembe.2012.10.022
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发表时间：
2013-01-01
影响因子：
2
通讯作者：
Kamiya, Hisao
中科院分区：
文献类型：
--
作者：
Jimbo, Mitsuru;Suda, Yuya;Kamiya, Hisao
我们之前证明，从八珊瑚Sinularia lochmodes 中分离出的凝集素SLL-2 可以与珊瑚内的共生微藻Symbiodinium 结合。结合 SLL-2 后，共生藻细胞从有鞭毛的游动形式转变为无鞭毛的球状形式，后者的形态与珊瑚中发现的共生阶段相似。然而，共生藻细胞表面凝集素识别的位点以及转化机制尚未阐明。我们发现，通过用糖苷酶预处理细胞或在培养基中添加 SLL-2 结合抑制剂 N-乙酰基-D-半乳糖胺，可以减弱 SLL-2 诱导共生藻细胞形态变化的能力。这些结果表明，共生藻细胞表面上的含β-半乳糖的糖缀合物是SLL-2诱导形态转化的关键配体。我们还发现，SLL-2 以高亲和力与 Forssman 抗原结合，通过添加抗 Forssman 鞘糖脂抗体来掩蔽 Symbiodinium 细胞上的结合位点，可抑制 SLL-2 与细胞的结合。抗体本身或其他 Forssman 抗原结合蛋白，例如 Helix pomatia 凝集素，可以在缺乏 SLL-2 的情况下将 Symbiodinium 细胞转化为球状阶段。由培养的共生藻细胞制备的中性脂质组分与抗福斯曼鞘糖脂抗体发生反应，支持共生藻细胞表面的福斯曼抗原样鞘糖脂参与凝集素 SLL-2 诱导的形态转变的假设。 (C) 2012 Elsevier B.V. 保留所有权利。
We previously demonstrated that the lectin SLL-2, isolated from the octocoral Sinularia lochmodes, binds to the symbiotic microalgae Symbiodinium within the coral. Upon binding SLL-2, Symbiodinium cells transform from a flagellated swimming form into a non-flagellated coccoid form, the latter morphologically similar to the symbiotic stage found in corals. However, the site recognized by the lectin on the surface of Symbiodinium cells and the transformation mechanism have yet to be elucidated. We found that the ability of SLL-2 to induce the morphological change in Symbiodinium cells can be attenuated by pretreating the cells with glycosidases or by adding the SLL-2 binding inhibitor N-acetyl-D-galactosamine to the culture medium. These results suggest that p-galactose-containing glycoconjugates on the Symbiodinium cell surface are the key ligand through which SLL-2 induces morphological transformation. We also found that SLL-2 binds with high affinity to the Forssman antigen, and masking the binding site on Symbiodinium cells by addition of anti-Forssman glycosphingolipid antibody inhibits the binding of SLL-2 to the cells. The antibody itself or other Forssman antigen-binding proteins, such as Helix pomatia agglutinin, can transform Symbiodinium cells into the coccoid stage in the absence of SLL-2. A neutral lipid fraction prepared from cultured Symbiodinium cells reacted with the anti-Forssman glycosphingolipid antibody, supporting the hypothesis that a Forssman antigen-like glycosphingolipid on the surface of Symbiodinium cells is involved in their morphological transformation induced by the lectin SLL-2. (C) 2012 Elsevier B.V. All rights reserved.