Sulfur assimilation in corals with aposymbiotic and symbiotic zooxanthellae
Sulfur assimilation in corals with aposymbiotic and symbiotic zooxanthellae
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DOI：
10.1111/1758-2229.12908
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发表时间：
2020-11-30
影响因子：
3.3
通讯作者：
Sano, Yuji
中科院分区：
文献类型：
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作者：
Higuchi, Tomihiko;Tanaka, Kentaro;Sano, Yuji
虽然硫酸根离子是海洋中硫的主要形式，但对生物体使用它们的知识有限。本研究使用稳定同位素标记和NanoSIMS分析来阐明海水中的硫酸盐如何在细胞水平上被珊瑚和虫黄藻同化。将Acropora属的离体共生和共生珊瑚幼鱼在含有S-34标记硫酸盐的过滤海水中孵育2天。此外，将标记的珊瑚在天然海水中再孵育2天。硫同位素（S-34/S-32）的映射表明，“热点”富集在S-34在亚微观水平上，并不均匀地分布在珊瑚软组织。具体而言，S-34热点被发现在共生虫黄藻和珊瑚宿主组织。在脱共生珊瑚中，在组织中检测到S-34，表明宿主珊瑚直接同化硫酸根离子，而不需要虫黄藻的任何帮助。即使在正常海水中2天后，S-34标记在共生和非共生珊瑚中都清晰可见，表明同化的硫至少保留了2天。
Although sulfate ions are the main form of sulfur in the ocean, there is limited knowledge on their use by living organisms. Stable isotope labelling and NanoSIMS analysis were used in this study to clarify how sulfate, in seawater, is assimilated by corals and zooxanthellae at the cellular level. Aposymbiotic and symbiotic coral juveniles from the genus Acropora were incubated for 2 days in filtered seawater with S-34-labelled sulfate. Further, the labelled corals were incubated for additional 2 days in natural seawater. Mapping of sulfur isotopes (S-34/S-32) showed that the 'hotspots' were enriched in S-34 on a sub-micro level and were heterogeneously distributed in the coral soft tissues. Specifically, S-34 hotspots were found in both the symbiotic zooxanthellae and coral host tissues. In aposymbiotic corals, S-34 was detected in the tissues, indicating that the host corals directly assimilated the sulfate ions without any aid from the zooxanthellae. Even after 2 days in normal seawater, the S-34 label was clearly seen in both symbiotic and aposymbiotic corals, indicating that the assimilated sulfur was retained for at least 2 days.