Durham Kathryn A, Porta David, Twiss Michael R, McKay R Michael L, Bullerjahn George S
Department of Biological Sciences, Life Sciences Building, Bowling Green State University, OH 43403-0212, USA.
FEMS Microbiol Lett. 2002 Apr 9;209(2):215-21. doi: 10.1111/j.1574-6968.2002.tb11134.x.
A Synechococcus sp. PCC 7942 bioreporter strain capable of sensing bioavailable Fe was constructed by fusing the Fe-responsive isiAB promoter to the Vibrio harveyi luxAB genes. Monitoring luxAB-dependent luminescence through the growth curve demonstrated that in Fe-replete media, transcription from the isiAB promoter was induced transiently in the mid-exponential phase of growth. The initiation of transcription was the functional response to a 10-fold depletion of intracellular Fe to approximately 12 amol Fe per cell. Constitutive isiAB-dependent transcription was observed in Fe-depleted growth media. A dose-response relationship of the bioreporter was generated using trace metal-buffered Fraquil medium and was best represented by a sigmoidal curve having a linear component extending between pFe 21.1 (Fe3+=10(-21.1) M) and pFe 20.6 (Fe3+)=10(-20.6) M). Initial field trials conducted using water sampled from Lake Erie demonstrate that the bioreporter can serve as a quantitative tool to assess Fe deficiency in natural freshwater environments.
通过将铁响应性 isiAB 启动子与哈维弧菌 luxAB 基因融合，构建了一种能够感知生物可利用铁的聚球藻属 Synechococcus sp. PCC 7942 生物报告菌株。通过生长曲线监测 luxAB 依赖性发光表明，在铁充足的培养基中，isiAB 启动子的转录在生长的指数中期被短暂诱导。转录的起始是对细胞内铁含量降低 10 倍至每细胞约 12 个阿托摩尔铁的功能性反应。在缺铁的生长培养基中观察到组成型 isiAB 依赖性转录。使用微量金属缓冲的 Fraquil 培养基建立了生物报告菌株的剂量反应关系，最佳表现为一条 S 形曲线，其线性部分在 pFe 21.1（Fe3+=10(-21.1) M）和 pFe 20.6（Fe3+）=10(-20.6) M 之间延伸。使用从伊利湖采集的水样进行的初步现场试验表明，该生物报告菌株可作为评估天然淡水环境中铁缺乏情况的定量工具。
