This research study deals with the on-line detection of heavy metals and toxicity within the context of environmental pollution monitoring. It describes the construction and the proof of concept of a multi-channel bioluminescent bacterial biosensor in immobilized phase: Lumisens3. This new versatile device, designed for the non-stop analysis of water pollution, enables the insertion of any bioluminescent strains (inducible or constitutive), immobilized in a multi-well removable card. The technical design of Lumisens3 has benefited from both a classical and a robust approach and includes four main parts: (1) a dedicated removable card contains 64 wells, 3 mm in depth, arranged in eight grooves within which bacteria are immobilized, (2) this card is incubated on a Pelletier block with a CCD cooled camera on top for bioluminescence monitoring, (3) a fluidic network feeds the card with the sample to be analyzed and finally (4) a dedicated computer interface, BIOLUX 1.0, controls all the elements of the biosensor, allowing it to operate autonomously. The proof of concept of this biosensor was performed using a set of four bioluminescent bacteria (Escherichia coli DH1 pBzntlux, pBarslux, pBcoplux, and E. coli XL1 pBfiluxCDABE) in the online detection of CdCl(2) 0.5 μM and As(2)O(3) 5 μM from an influent. When considering metals individually, the "fingerprints" from the biosensor were as expected. However, when metals were mixed together, cross reaction and synergistic effects were detected. This biosensor allowed us to demonstrate the simultaneous on-line cross detection of one or several heavy metals as well as the measurement of the overall toxicity of the sample.

This study describes the construction of inducible bioluminescent strains via genetic engineering along with their characterization and optimization in the detection of heavy metals. Firstly, a preliminary comparative study enabled us to select a suitable carbon substrate from pyruvate, glucose, citrate, diluted Luria-Bertani, and acetate. The latter carbon source provided the best induction ratios for comparison. Results showed that the three constructed inducible strains, Escherichia coli DH1 pBzntlux, pBarslux, and pBcoplux, were usable when conducting a bioassay after a 14-h overnight culture at 30 °C. Utilizing these sensors gave a range of 12 detected heavy metals including several cross-detections. Detection limits for each metal were often close to and sometimes lower than the European standards for water pollution. Finally, in order to maintain sensitive bacteria within the future biosensor-measuring cell, the agarose immobilization matrix was compared to polyvinyl alcohol (PVA). Agarose was selected because the detection limits of the bioluminescent strains were not affected, in contrast to PVA. Specific detection and cross-detection ranges determined in this study will form the basis of a multiple metals detection system by the new multi-channel Lumisens3 biosensor.

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International audienceNew methods for pathogens identification are of growing interest in clinical and food sectors. The challenge remains to develop rapid methods that are more simple, reliable, and specific. Surface-enhanced Raman spectroscopy (SERS) appears to be a promising tool to compete with current untargeted identification methods. This article presents the intensive research devoted to the use of SERS for bacterial identification, from the first to the very recent published results. Compared to normal Raman spectroscopy, the introduction of nanoparticles for SERS acquisition introduces a new degree of complexity. Bacterial Raman fingerprints, which are already subject to high spectral variability for a given strain, become then very dependent on numerous experimental parameters. To overcome these limitations, several approaches have been proposed to prepare the sample, from the microbiological culture conditions to the analysis of the spectrum including the coupling of nanoparticles on the bacterial membrane. Main strategies proposed over the last 20 years are examined here and discussed in the perspective of a protocol transfer towards industry

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Souvent considéré comme impactant pour les ressources en eau et la biodiversité, le golf implique des activités d’entretien des gazons récurrentes et des surfaces de jeu souvent importantes. Plus de 30 000 hectares sur le territoire métropolitain sont ainsi dédiés à des terrains de golf. Le tableau est-il si noir pour l’environnement ? La question des impacts environnementaux des structures golfiques, comme d’autres activités humaines, doit être posée dans un contexte global d’érosion de la biodiversité. Dans la mesure où une activité répond à une demande sociale et économique voire sociétale forte, l’idée n’est pas de se positionner « pour » ou « contre » mais bien de l’accompagner pour qu’elle soit la moins impactante pour l’environnement. La réduction des incidences environnementales est une nécessité pour la filière golfique. Les éléments décrits dans cet article démontrent que dans bien des cas, les golfs peuvent être supports de connaissances scientifiques, jusque-là très parcellaires sur ces sites, voire de restauration ou de conservation de la nature. Fort d’un engagement sur plusieurs années, la Fédération française de golf, avec l’appui scientifique et technique du Muséum national d’Histoire naturelle, a lancé récemment le « Programme golf pour la biodiversité », s’inscrivant dans cette dynamique. Ce programme vise à favoriser les partenariats entre structures golfiques et naturalistes pour mieux connaître et préserver la biodiversité dans les espaces golfiques. Il ne répondra pas à lui seul à l’ensemble des défis actuels de la filière golfique, mais participe à l’adhésion généralisée à cette transition écologique, nécessaire à l’avenir de ce sport « de nature ».