Whole-cell biosensors for detection of heavy metal ions in environmental samples based on metallothionein promoters from Tetrahymena thermophila
Article first published online: 1 MAR 2011
Published 2011. This article is a US Government work and is in the public domain in the USA. Journal compilation © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd
Thematic Issue: Extremophiles
Volume 4, Issue 4, pages 513–522, July 2011
How to Cite
Amaro, F., Turkewitz, A. P., Martín-González, A. and Gutiérrez, J.-C. (2011), Whole-cell biosensors for detection of heavy metal ions in environmental samples based on metallothionein promoters from Tetrahymena thermophila. Microbial Biotechnology, 4: 513–522. doi: 10.1111/j.1751-7915.2011.00252.x
- Issue published online: 6 JUL 2011
- Article first published online: 1 MAR 2011
- Received 30 September, 2010; accepted 13 January, 2011.
Fig. S1. Time course of MTT5Luc response to Cd2+ (5 × 10−7 mol L−1). Data represent the average values from two different experiments.
Fig. S2. Comparative bioluminescence response, at different Cd2+ (mol L−1) concentrations. Whole-cells (in vivo bioassay) (black line), cell extracts (in vitro bioassay) (black bars) or permeabilized cells (grey bars) of both MTT1Luc (A) or MTT5Luc (B) biosensors.
Fig. S3. MTT5Luc response to different metal mixtures. (A): Cd2+ + Cu2+, (B): Cd2+ + Zn2+, (C): Cd2+ + Pb2+, (D): Cu2+ + Zn2+. Cd2+ or Cu2+ molar concentrations: 0 mol L−1 (white bars), 2.5 × 10−7 mol L−1 (grey bars), 5 × 10−7 mol L−1 (black bars). Bioluminescence measures were carried out in vitro. Heavy metal interactions are pointed out on the corresponding bars as A (additive) or S (synergistic).
Fig. S4. The MTT5Luc response depends on Cd2+ bioavailability. Control (black circles): Cells were exposed to Cd2+ at the molar concentrations shown, for 2h in Tris-HCl buffer. EDTA (1) and (2): 4h prior to mixing with cells, the Cd2+ was chelated by addition of 1 µmol L−1 EDTA (white circles) or 10 µmol L−1 EDTA (black triangles).
Fig. S5. Biosensor response to different non-metal stressors. (A) MTT1Luc in PP210 medium. (B) MTT1Luc in Tris-HCl buffer. (C) MTT5Luc in PP210. (D) MTT5Luc in Tris-HCl buffer. All treatments were during 2h. PQ: Paraquat.
Fig. S6. Expression analysis of reporter gene (lucFF) by quantitative RT-PCR. Relative expression of the reporter gene lucFF from MTT1Luc (white bars) and MTT5Luc (black bars), obtained by qRT-PCR of cells exposed (2 h) to diverse heavy metals (5 × 10−7 mol L−1) in Tris-HCl buffer (pH 6.8). Gene expression levels are shown relative to an untreated control (which is set at 1 ± 0.0), and ATU1 (α-tubulin) gene expression was used to normalize all samples. Each bar represents the average of two independent experiments. (*): Significantly different from the control at p < 0.05.
Fig. S7. MTT5Luc response to Cd2+ added to a non-contaminated (by heavy metals) natural aquatic sample. Natural aquatic sample + Cd2+ (black bars). Control (0 Cd2+): sample without added Cd2+. Cd2+ + 10 µmol L−1 EDTA (grey bars).
Table S1. Total metal content of soil samples used in experiments shown in Fig. 4.
Table S2. Ranking sensitivity to different heavy metals by previously reported eukaryotic or prokaryotic WCBs and the MTT1Luc and MTT5Luc strains.
Appendix S1. Experimental procedures.
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