Rudd David, Ronci Maurizio, Johnston Martin R, Guinan Taryn, Voelcker Nicolas H, Benkendorff Kirsten
School of Biological Sciences, Flinders University, Bedford Park, SA 5042, Australia.
Mawson Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
Sci Rep. 2015 Sep 1;5:13408. doi: 10.1038/srep13408.
Despite significant advances in chemical ecology, the biodistribution, temporal changes and ecological function of most marine secondary metabolites remain unknown. One such example is the association between choline esters and Tyrian purple precursors in muricid molluscs. Mass spectrometry imaging (MSI) on nano-structured surfaces has emerged as a sophisticated platform for spatial analysis of low molecular mass metabolites in heterogeneous tissues, ideal for low abundant secondary metabolites. Here we applied desorption-ionisation on porous silicon (DIOS) to examine in situ changes in biodistribution over the reproductive cycle. DIOS-MSI showed muscle-relaxing choline ester murexine to co-localise with tyrindoxyl sulfate in the biosynthetic hypobranchial glands. But during egg-laying, murexine was transferred to the capsule gland, and then to the egg capsules, where chemical ripening resulted in Tyrian purple formation. Murexine was found to tranquilise the larvae and may relax the reproductive tract. This study shows that DIOS-MSI is a powerful tool that can provide new insights into marine chemo-ecology.
尽管化学生态学取得了重大进展，但大多数海洋次生代谢产物的生物分布、时间变化和生态功能仍然未知。一个例子是骨螺科软体动物中胆碱酯类与泰尔紫前体之间的关联。纳米结构表面的质谱成像（MSI）已成为用于异质组织中低分子量代谢物空间分析的复杂平台，非常适合低丰度次生代谢物。在这里，我们应用多孔硅解吸电离（DIOS）来研究生殖周期中生物分布的原位变化。DIOS-MSI显示，具有肌肉松弛作用的胆碱酯类物质墨海胆素与硫酸酪氨酸在生物合成的鳃下腺中共定位。但在产卵期间，墨海胆素转移到壳腺，然后转移到卵囊，在那里化学成熟导致泰尔紫形成。研究发现，墨海胆素可使幼虫安静下来，并可能使生殖道松弛。这项研究表明，DIOS-MSI是一种强大的工具，可为海洋化学生态学提供新的见解。
