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Scientific article
English

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

Contributors

Hassler, Christel; Twiss, Michael R.; McKay, R. Michael L.; Bullerjahn, George S.

Published in

Journal of phycology, vol. 42, no. 2, p. 324-335

Publication date

2006

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 umol photons .m-2 . s-1 (37–200 umol photons m-2 . s-1), initial biomass of 0.6–0.8 ug chlorophylla (chl a) .L-1 (0.3–1.5 ug chl a .L-1) or approximately 1exp 5 bioreporter cells .mL-1, high phosphate (10 uM), and low micronutrients (absent). The measured luminescence was optimal with an exogenous addition of 60 uM 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.

UNIGE affiliation entities

Not a UNIGE publication

Citation (ISO format)

HASSLER, Christel et al. Optimization of iron-dependent cyanobacterial (Synechococcus, Cyanophyceae) bioreporters to measure iron bioavailability. In: Journal of phycology, 2006, vol. 42, n° 2, p. 324–335. doi: 10.1111/j.1529-8817.2006.00203.x

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Article (Published version)

Identifiers

Journal ISSN

0022-3646
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Technical informations

Creation

10/02/2013 20:15:00

First validation

10/02/2013 20:15:00

Update

14/03/2023 20:03:06

Status update

14/03/2023 20:03:06

Last indexation

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