Metallophores associated with Trichodesmium erythraeum colonies from the Gulf of Aqaba
Metallophores associated with Trichodesmium erythraeum colonies from the Gulf of Aqaba
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DOI：
10.1039/c9mt00121b
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发表时间：
2019-09-01
期刊：
影响因子：
3.4
通讯作者：
Shaked, Yeala
中科院分区：
文献类型：
--
作者：
Gledhill, Martha;Basu, Subhajit;Shaked, Yeala
束毛藻是一种重要的海洋固氮蓝细菌，它能形成群体并利用大气中产生的灰尘作为限制性微量营养铁的来源。在这里，我们报告的鉴定，从红海的亚喀巴湾收集的天然束毛藻菌落孵化分离的金属载体。我们的三个化合物被鉴定为铁氧胺铁载体B、E和G。剩下的15个金属载体的质荷比，据我们所知，是不常见的已知铁载体。推定的总和公式表明，这些化合物中的大多数在结构上彼此无关。我们还发现，新的金属载体很容易与铝形成络合物，并且对铁的特异性低于铁草胺。在我们培养的束毛藻菌落中，10种新型金属载体的丰度与束毛藻生物量呈正相关，但与细菌生物量无关，而铁氧胺铁载体与细菌生物量更密切相关。我们在亚喀巴湾的过滤表层海水样品中发现了铁草胺和我们的新型金属载体。然而，我们的新型金属载体仅在最高束毛藻丰度时收集的表层海水样品中观察到，而即使在不存在束毛藻的情况下也观察到了铁草胺。我们推测，新的金属载体是专门与束毛藻殖民地。与细菌产生的铁草胺一起，它们可能有助于在束毛藻菌落周围形成独特的“配体圈”，对殖民地环境中的金属稳态具有潜在影响。
Trichodesmium is a globally important marine nitrogen fixing cyanobacteria which forms colonies and utilizes atmospherically derived dust as a source for the limiting micro-nutrient iron. Here we report the identification of metallophores isolated from incubations of natural Trichodesmium colonies collected from the Gulf of Aqaba in the Red Sea. Three of our compounds were identified as the ferrioxamine siderophores B, E, and G. The remaining fifteen metallophores had mass to charge ratios that, to our knowledge, are not common to known siderophores. Putative sum formulas suggest most of these compounds were not structurally related to each other. We also found that the novel metallophores readily formed complexes with aluminium and were less specific for iron than the ferrioxamines. In our incubations of Trichodesmium colonies, the abundance of ten of the novel metallophores positively correlated with Trichodesmium biomass, but not with bacterial biomass, whilst ferrioxamine siderophores were more strongly associated with bacterial biomass. We identified ferrioxamines and our novel metallophores in filtered surface seawater samples from the Gulf of Aqaba. However, our novel metallophores were only observed in the surface seawater sample collected at the time of highest Trichodesmium abundance, while ferrioxamines were observed even when Trichodesmium was not present. We hypothesize that the novel metallophores were specifically associated with Trichodesmium colonies. Together with the bacterially produced ferrioxamines they likely contribute to a distinctive "ligandosphere" surrounding the Trichodesmium colonies, with potential implications for metal homeostasis within the colony environment.