Construction and initial characterization of a luminescent Synechococcus sp. PCC 7942 Fe-dependent bioreporter.
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.
Durham
Kathryn A
KA
Department of Biological Sciences, Life Sciences Building, Bowling Green State University, OH 43403-0212, USA.
Porta
David
D
Twiss
Michael R
MR
McKay
R Michael L
RM
Bullerjahn
George S
GS
D015374:Biosensing Techniques; D003470:Culture Media / Q000737:chemistry; D000458:Cyanobacteria / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D005618:Fresh Water / Q000737:chemistry*; D017930:Genes, Reporter / Q000187:drug effects / Q000235:genetics*; D007501:Iron / Q000032:analysis / Q000494:pharmacology*; D008164:Luminescent Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics
D003470:Culture Media; D008164:Luminescent Proteins; D007501:Iron