SGER: Development of a Reporter System Regulated by the Biological Availability of Fe in Saltwater

铁（Fe）作为海洋系统生物生产力的限制因子的作用已被广泛研究。已知海洋原核生物在限制铁的生长条件下保持产生铁载体（或至少类似铁载体的化合物）的能力。虽然研究分析技术可以在非常小的浓度下量化总铁，并提供有关铁形态的信息，但我们仍然没有这种铁对自然群落的生物有效性的指标。为了了解铁在全球海洋生产力中的作用，需要量化真正生物可利用铁的工具/技术。由于水生生物可以确定自身的铁状态，因此基于海洋生物铁感知系统的工具将是最好的。研究人员已经开发出一种具有发光报告的基因工程微生物（GEM），它使用海洋细菌的天然铁摄取调节蛋白（Fur）直接响应铁的生物利用度。研究人员现在将尝试将报告菌整合到其他10种海洋细菌中。实验室实验将建立铁生物利用度和光产量之间的关系。GEMs作为铁生物利用度报告器的现场测试将在马尾藻海、伊利湖和秘鲁上升流地区进行。

The role of iron (Fe) as a limiting agent of biological productivity in marine systems has been studied extensively. Marine prokaryotic organisms are known to maintain the ability to produce siderophore (or at least siderophore-like compounds) in response to Fe-limiting growth conditions. While research analytical techniques can quantify total Fe at incredibly small concentrations and provide information on Fe speciation, we remain without indicators of the biological availability of this Fe to natural communities. To understand the role that Fe plays in global marine productivity, tools/techniques for quantifying truly bioavailable iron are needed. Since organisms in aquatic systems can determine their own Fe status, a tool based on the Fe sensing system of a marine organism would be the best. The investigators have developed a genetically engineered microorganism (GEM) with a luminescent reporter that directly responds to Fe bioavailability using the native ferric-uptake-regulator (Fur) protein of a marine bacterium. The researchers will now attempt integration of the reporter into ten other strains of marine bacteria. Laboratory experiments will establish the relationship between Fe bioavailability and light production. Field testing of the GEMs as Fe bioavailability reporters will be conducted on cruises of opportunity in the Sargasso Sea, Lake Erie, and the Peru upwelling region.