Optimization of iron-dependent cyanobacterial (Synechococcus, Cyanophyceae) bioreporters to measure iron bioavailability

Hassler, CS; Twiss, MR; McKay, RML; Bullerjahn, GS

Optimization of iron-dependent cyanobacterial (Synechococcus, Cyanophyceae) bioreporters to measure iron bioavailability

Hassler, CS Twiss, MR McKay, RML Bullerjahn, GS

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Publication Type:: Journal Article
Citation:: Journal of Phycology, 2006, 42 (2), pp. 324 - 335
Issue Date:: 2006-04-01

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Field	Value	Language
dc.contributor.author	Hassler, CS	en_US
dc.contributor.author	Twiss, MR	en_US
dc.contributor.author	McKay, RML	en_US
dc.contributor.author	Bullerjahn, GS	en_US
dc.date.issued	2006-04-01	en_US
dc.identifier.citation	Journal of Phycology, 2006, 42 (2), pp. 324 - 335	en_US
dc.identifier.issn	0022-3646	en_US
dc.identifier.uri	http://hdl.handle.net/10453/8688
dc.description.abstract	Complex chemistry and biological uptake pathways render iron bioavailability particularly difficult to assess in natural waters. Bioreporters are genetically modified organisms that are useful tools to directly sense the bioavailable fractions of solutes. In this study, three cyanobacterial bioreporters derived from Synechococcus PCC 7942 were examined for the purpose of optimizing the response to bioavailable Fe. Each bioreporter uses a Fe-regulated promoter (isiAB, irpA and mapA), modulated by distinct mechanisms under Fe deficiency, fused to a bacterial luciferase (luxAB). In order to provide a better understanding of the way natural conditions may affect the ability of the bioreporter to sense iron bioavailability, the effect of relevant environmental parameters on the response to iron was assessed. Optimal conditions (and limits of applicability) for the use of these bioreporters on the field were determined to be: a 12 h (12-24 h) exposure time, temperature of 15°C (15°C-22°C), photon flux density of 100 μmol photons·m-2·s-1 (37-200 μmol photons·m-2·s-1), initial biomass of 0.6-0.8 μg chlorophyll a (chl a)·L-1 (0.3-1.5 μg chl a·L-1) or approximately 105 bioreporter cells·mL-1, high phosphate (10 μM), and low micronutrients (absent). The measured luminescence was optimal with an exogenous addition of 60 μM aqueous decanal substrate allowing a 5 min reaction time in the dark before analysis. This study provides important considerations relating to the optimization in the use of bioreporters under field conditions that can be used for method development of other algal and cyanobacterial bioreporters in aquatic systems. © 2006 Phycological Society of America.	en_US
dc.relation.ispartof	Journal of Phycology	en_US
dc.relation.isbasedon	10.1111/j.1529-8817.2006.00203.x	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	Optimization of iron-dependent cyanobacterial (Synechococcus, Cyanophyceae) bioreporters to measure iron bioavailability	en_US
dc.type	Journal Article
utslib.citation.volume	2	en_US
utslib.citation.volume	42	en_US
utslib.for	0607 Plant Biology	en_US
utslib.for	0704 Fisheries Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
utslib.copyright.status	closed_access
pubs.issue	2	en_US
pubs.publication-status	Published	en_US
pubs.volume	42	en_US

Abstract:

Complex chemistry and biological uptake pathways render iron bioavailability particularly difficult to assess in natural waters. Bioreporters are genetically modified organisms that are useful tools to directly sense the bioavailable fractions of solutes. In this study, three cyanobacterial bioreporters derived from Synechococcus PCC 7942 were examined for the purpose of optimizing the response to bioavailable Fe. Each bioreporter uses a Fe-regulated promoter (isiAB, irpA and mapA), modulated by distinct mechanisms under Fe deficiency, fused to a bacterial luciferase (luxAB). In order to provide a better understanding of the way natural conditions may affect the ability of the bioreporter to sense iron bioavailability, the effect of relevant environmental parameters on the response to iron was assessed. Optimal conditions (and limits of applicability) for the use of these bioreporters on the field were determined to be: a 12 h (12-24 h) exposure time, temperature of 15°C (15°C-22°C), photon flux density of 100 μmol photons·m-2·s-1 (37-200 μmol photons·m-2·s-1), initial biomass of 0.6-0.8 μg chlorophyll a (chl a)·L-1 (0.3-1.5 μg chl a·L-1) or approximately 105 bioreporter cells·mL-1, high phosphate (10 μM), and low micronutrients (absent). The measured luminescence was optimal with an exogenous addition of 60 μM aqueous decanal substrate allowing a 5 min reaction time in the dark before analysis. This study provides important considerations relating to the optimization in the use of bioreporters under field conditions that can be used for method development of other algal and cyanobacterial bioreporters in aquatic systems. © 2006 Phycological Society of America.

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http://hdl.handle.net/10453/8688