Two novel cyanobacterial bioluminescent whole-cell bioreporters based on superoxide dismutases MnSod and FeSod to detect superoxide anion

Abstract

This work describes the construction of two novel self-luminescent bioreporter strains of the cyanobacterium Nostoc sp. PCC 7120 by fusing the promoter region of the sodA and sodB genes (encoding the superoxide dismutases MnSod and FeSod, respectively) to luxCDABE from Photorhabdus luminescens aimed at detecting pollutants that generate reactive oxygen species (ROS), particularly O. Bioreporters were tested against methyl viologen (MV) as the inducer of superoxide anion (O). Both bioreporters were specific for O and Limits of detection (LODs) and Maximum Permissive Concentrations (MPCs) were calculated: Nostoc sp. PCC 7120 pBG2154 (sodA) had a range of detection from 400 to 1000 pM of MV and for Nostoc sp. PCC 7120 pBG2165 (sodB) the range of detection was from 500 to 1800 pM of MV after 5 h-exposure. To further validate the bioreporters, they were tested with the emerging pollutant Triclosan which induced bioluminescence in both strains. Furthermore, the bioreporters performance was tested in two real environmental samples with different water matrix complexity, spiked with MV. Both bioreporters were induced by O in these environmental samples. In the case of the river water sample, the amount of bioavailable MV as calculated from the bioreporters output was similar to that nominally added. For the waste water sample, the bioavailable MV concentration detected by the bioreporters was one order of magnitude lower than nominal. These differences could be due to MV complexation with organic matter and/or co-occurring organic contaminants. These results confirm their high sensitivity to O and their suitability to detect oxidative stress-generating pollutants in fresh-waters.

Enzymatic Antioxidant Signatures in Hyperthermophilic Archaea

“…A detailed understanding of the molecular mechanisms responsible for the response to oxidative stress is fundamental for engineering organisms and developing bioreporters to measure the bioavailability of many emerging pollutants in the environment. In this regard, bioreporter strains that respond to oxidative stress can be constructed using the promoters of the genes encoding antioxidant enzymes, such as Prx or SOD, which are able to respond to increased oxidative stress, fused to suitable reporter genes [99]. Although bioreporter strains have not yet been developed for hyperthermophilic archaea, the utilization of thermophilic molecular components and thermostable chassis cells has already been considered promising in biosensing applications [100].…”

Triclosan: An Update on Biochemical and Molecular Mechanisms

“…TCS was also recently used to validate novel self-luminescent bioreporter strains of Nostoc sp. PCC 7120 using Sod promoters [127].…”

Use of Cyanobacterial Luminescent Bioreporters to Report on the Environmental Impact of Metallic Nanoparticles

“…Briefly the bioluminescent transformed strains based on Nostoc sp. PCC7120 which detect ROS [29,30] were grown in AA/8+N culture medium at 28 °C with continuous illumination, at 60 µmol photons m²sˉ¹ on a rotatory shaker in 250 mL Erlenmeyer flasks. Culture medium was supplemented with spectinomycin (Sp) (2 µg/mL).…”

“…PCC7120 bioreporters (Table 1). These bioreporters have been previously used to detect ROS formation caused by the herbicide methyl viologen (MV or paraquat), H 2 O 2 , and the emerging pollutant triclosan [29,30].…”

“…PCC7120 pBG2154, Nostoc sp. PCC7120 pBG2165 [29] and Nostoc sp. PCC7120 pBG2173 [30] which detect specifically superoxide anion and Nostoc sp.…”