Mass spectrometry imaging reveals differential localization of natural sunscreens in the mantle of the giant clam Tridacna crocea
Mass spectrometry imaging reveals differential localization of natural sunscreens in the mantle of the giant clam Tridacna crocea
复制标题
DOI：
10.1038/s41598-019-57296-9
复制
发表时间：
2020-01-20
影响因子：
4.6
通讯作者：
Sakai, Ryuichi
中科院分区：
文献类型：
--
作者：
Goto-Inoue, Naoko;Sato, Tomohiko;Sakai, Ryuichi
巨蛤已经进化到可以最大限度地利用光共生伙伴的阳光，同时保护它们免受有害的紫外线（UV）的伤害。地幔中存在的紫外线吸收物质被认为对于光保护至关重要。然而，此类化合物的确切定位仍然未知。在这里，我们结合使用紫外液相色谱 (LC)、LC-质谱 (MS)、MS 成像和紫外显微摄影来定位大砗磲中的紫外线吸收物质。 LC-MS 分析显示，该动物含有三类菌孢子素：祖菌孢子素、原代菌孢子素和次生菌孢子素。 MS 成像显示，初级和次级菌孢子位于地幔的最外层；而祖菌孢子素分布在整个套组织中。这些发现与紫外显微摄影的结果一致，后者揭示了地幔表层吸收了 320 +/- 10 nm 的紫外光。这是第一份表明祖菌孢子素和初级菌孢子素被巨蛤代谢为次生菌孢子素的报告，并且它们在地幔的表层中存在差异，以保护动物免受紫外线的伤害。
Giant clams have evolved to maximize sunlight utilization by their photosymbiotic partners, while affording them protection from harmful ultraviolet (UV) light. The presence of UV absorbing substances in the mantle is thought to be critical for light protection; however, the exact localization of such compounds remains unknown. Here, we applied a combination of UV liquid chromatography (LC), LC-mass spectrometry (MS), MS imaging, and UV micrography to localize UV absorbing substances in the giant clam Tridacna crocea. LC-MS analysis revealed that the animal contained three classes of mycosporines: progenitor, primary, and secondary mycosporines. MS imaging revealed that primary and secondary mycosporines were localized in the outermost layer of the mantle; whereas progenitor mycosporines were distributed throughout the mantle tissue. These findings were consistent with the results of UV micrography, which revealed that the surface layer of the mantle absorbed UV light at 320 +/- 10nm. This is the first report indicating that progenitor and primary mycosporines are metabolized to secondary mycosporines by the giant clam and that they are differentially localized in the surface layer of the mantle to protect the animal from UV light.