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Accueil > Départements > Microbiologie > Franck CHAUVAT : Biologie et Biotechnologie des Cyanobactéries

Publications de l’équipe



  • C. Cassier-Chauvat, V. Dive, et F. Chauvat, « Cyanobacteria: photosynthetic factories combining biodiversity, radiation resistance, and genetics to facilitate drug discovery », Applied Microbiology and Biotechnology, vol. 101, nᵒ 4, p. 1359-1364, févr. 2017.
    Résumé : Cyanobacteria are ancient, abundant, and widely diverse photosynthetic prokaryotes, which are viewed as promising cell factories for the ecologically responsible production of chemicals. Natural cyanobacteria synthesize a vast array of biologically active (secondary) metabolites with great potential for human health, while a few genetic models can be engineered for the (low level) production of biofuels. Recently, genome sequencing and mining has revealed that natural cyanobacteria have the capacity to produce many more secondary metabolites than have been characterized. The corresponding panoply of enzymes (polyketide synthases and non-ribosomal peptide synthases) of interest for synthetic biology can still be increased through gene manipulations with the tools available for the few genetically manipulable strains. In this review, we propose to exploit the metabolic diversity and radiation resistance of cyanobacteria, and when required the genetics of model strains, for the production and radioactive ((14)C) labeling of bioactive products, in order to facilitate the screening for new drugs.
    Mots-clés : B2CYA, Biodiversity, Cyanobacteria, MICROBIO, Peptide Synthases, photosynthesis, Radioactive labeling, Secondary metabolites, Toxins.


  • C. Cassier-Chauvat, T. Veaudor, et F. Chauvat, « Comparative Genomics of DNA Recombination and Repair in Cyanobacteria: Biotechnological Implications », Frontiers in Microbiology, vol. 7, p. 1809, 2016.
    Résumé : Cyanobacteria are fascinating photosynthetic prokaryotes that are regarded as the ancestors of the plant chloroplast; the purveyors of oxygen and biomass for the food chain; and promising cell factories for an environmentally friendly production of chemicals. In colonizing most waters and soils of our planet, cyanobacteria are inevitably challenged by environmental stresses that generate DNA damages. Furthermore, many strains engineered for biotechnological purposes can use DNA recombination to stop synthesizing the biotechnological product. Hence, it is important to study DNA recombination and repair in cyanobacteria for both basic and applied research. This review reports what is known in a few widely studied model cyanobacteria and what can be inferred by mining the sequenced genomes of morphologically and physiologically diverse strains. We show that cyanobacteria possess many E. coli-like DNA recombination and repair genes, and possibly other genes not yet identified. E. coli-homolog genes are unevenly distributed in cyanobacteria, in agreement with their wide genome diversity. Many genes are extremely well conserved in cyanobacteria (mutMS, radA, recA, recFO, recG, recN, ruvABC, ssb, and uvrABCD), even in small genomes, suggesting that they encode the core DNA repair process. In addition to these core genes, the marine Prochlorococcus and Synechococcus strains harbor recBCD (DNA recombination), umuCD (mutational DNA replication), as well as the key SOS genes lexA (regulation of the SOS system) and sulA (postponing of cell division until completion of DNA reparation). Hence, these strains could possess an E. coli-type SOS system. In contrast, several cyanobacteria endowed with larger genomes lack typical SOS genes. For examples, the two studied Gloeobacter strains lack alkB, lexA, and sulA; and Synechococcus PCC7942 has neither lexA nor recCD. Furthermore, the Synechocystis PCC6803 lexA product does not regulate DNA repair genes. Collectively, these findings indicate that not all cyanobacteria have an E. coli-type SOS system. Also interestingly, several cyanobacteria possess multiple copies of E. coli-like DNA repair genes, such as Acaryochloris marina MBIC11017 (2 alkB, 3 ogt, 7 recA, 3 recD, 2 ssb, 3 umuC, 4 umuD, and 8 xerC), Cyanothece ATCC51142 (2 lexA and 4 ruvC), and Nostoc PCC7120 (2 ssb and 3 xerC).
    Mots-clés : B2CYA, Cyanobacteria, DNA recombination, DNA Repair, genetic instability, insertion sequences, MICROBIO, natural transformation, photoproduction, radiation resistance.

  • J. Li, I. Margaret Oliver, N. Cam, T. Boudier, M. Blondeau, E. Leroy, J. Cosmidis, F. Skouri-Panet, J. - M. Guigner, C. Férard, M. Poinsot, D. Moreira, P. Lopez-Garcia, C. Cassier-Chauvat, F. Chauvat, et K. Benzerara, « Biomineralization Patterns of Intracellular Carbonatogenesis in Cyanobacteria: Molecular Hypotheses », Minerals, vol. 6, nᵒ 1, p. 10, févr. 2016.

  • K. Narainsamy, S. Farci, E. Braun, C. Junot, C. Cassier-Chauvat, et F. Chauvat, « Oxidative-stress detoxification and signalling in cyanobacteria: the crucial glutathione synthesis pathway supports the production of ergothioneine and ophthalmate », Molecular Microbiology, vol. 100, nᵒ 1, p. 15-24, avr. 2016.
    Résumé : Using genetics and metabolomics we investigated the synthesis (gshA and gshB genes) and catabolism (ggt) of the conserved antioxidant glutathione in the model cyanobacterium Synechocystis PCC6803. These three genes are crucial to Synechocystis, in agreement with the proposed invention of glutathione by ancient cyanobacteria to protect themselves against the toxicity of oxygen they produced through photosynthesis. Consistent with their indispensability, gshA and gshB also operate in the production of another antioxidant, ergothioneine, as well as of the glutathione analogues ophthalmate and norophthalmate. Furthermore, we show that glutathione, ophthalmate and norophthalmate are accumulated in cells stressed by glucose, and that the two glutathione-dependent glyoxalase enzymes operate in the protection against glucose and its catabolite methylglyoxal. These findings are interesting because ophthalmate and norophthalmate were observed only in mammals so far, where ophthalmate is regarded as a biomarker of glutathione depletion. Instead, our data suggest that ophthalmate and norophthalmate are stress-induced markers of cysteine depletion triggered by its accelerated incorporation into glutathione, to face its increased demand for detoxification purposes. Hence, Synechocystis is an attractive model for the analysis of the role of glutathione, ergothioneine, ophthalmate and norophthalmate, in signalling and detoxification of oxidants and metabolic by-products.
    Mots-clés : B2CYA, Biosynthetic Pathways, Cyanobacteria, Ergothioneine, Genes, Bacterial, Glucose, Glutathione, Inactivation, Metabolic, Lactoylglutathione Lyase, MICROBIO, Oligopeptides, oxidative stress, Pyruvaldehyde, Signal Transduction, Synechocystis.


  • A. Bourgeault, C. Cousin, V. Geertsen, C. Cassier-Chauvat, F. Chauvat, O. Durupthy, C. Chanéac, et O. Spalla, « The challenge of studying TiO2 nanoparticle bioaccumulation at environmental concentrations: crucial use of a stable isotope tracer », Environmental Science & Technology, vol. 49, nᵒ 4, p. 2451-2459, févr. 2015.
    Résumé : The ecotoxicity of nanoparticles (NPs) is a growing area of research with many challenges ahead. To be relevant, laboratory experiments must be performed with well-controlled and environmentally realistic (i.e., low) exposure doses. Moreover, when focusing on the intensively manufactured titanium dioxide (TiO2) NPs, sample preparations and chemical analysis are critical steps to meaningfully assay NP's bioaccumulation. To deal with these imperatives, we synthesized for the first time TiO2 NPs labeled with the stable isotope (47)Ti. Thanks to the (47)Ti labeling, we could detect the bioaccumulation of NPs in zebra mussels (Dreissena polymorpha) exposed for 1 h at environmental concentrations via water (7-120 μg/L of (47)TiO2 NPs) and via their food (4-830 μg/L of (47)TiO2 NPs mixed with 1 × 10(6) cells/mL of cyanobacteria) despite the high natural Ti background, which varied in individual mussels. The assimilation efficiency (AE) of TiO2 NPs by mussels from their diet was very low (AE = 3.0 ± 2.7%) suggesting that NPs are mainly captured in mussel gut, with little penetration in their internal organs. Thus, our methodology is particularly relevant in predicting NP's bioaccumulation and investigating the factors influencing their toxicokinetics in conditions mimicking real environments.
    Mots-clés : Animals, B2CYA, Cyanobacteria, Dreissena, Environmental Exposure, Food Chain, Isotope Labeling, Isotopes, MICROBIO, Nanoparticles, Tissue Distribution, Titanium, Water Pollutants, Chemical.

  • S. Chardonnet, S. Sakr, C. Cassier-Chauvat, P. Le Maréchal, F. Chauvat, S. D. Lemaire, et P. Decottignies, « First proteomic study of S-glutathionylation in cyanobacteria », Journal of Proteome Research, vol. 14, nᵒ 1, p. 59-71, janv. 2015.
    Résumé : Glutathionylation, the reversible post-translational formation of a mixed disulfide between a cysteine residue and glutathione (GSH), is a crucial mechanism for signal transduction and regulation of protein function. Until now this reversible redox modification was studied mainly in eukaryotic cells. Here we report a large-scale proteomic analysis of glutathionylation in a photosynthetic prokaryote, the model cyanobacterium Synechocystis sp. PCC6803. Treatment of acellular extracts with N,N-biotinyl glutathione disulfide (BioGSSG) induced glutathionylation of numerous proteins, which were subsequently isolated by affinity chromatography on streptavidin columns and identified by nano LC-MS/MS analysis. Potential sites of glutathionylation were also determined for 125 proteins following tryptic cleavage, streptavidin-affinity purification, and mass spectrometry analysis. Taken together the two approaches allowed the identification of 383 glutathionylatable proteins that participate in a wide range of cellular processes and metabolic pathways such as carbon and nitrogen metabolisms, cell division, stress responses, and H2 production. In addition, the glutathionylation of two putative targets, namely, peroxiredoxin (Sll1621) involved in oxidative stress tolerance and 3-phosphoglycerate dehydrogenase (Sll1908) acting on amino acids metabolism, was confirmed by biochemical studies on the purified recombinant proteins. These results suggest that glutathionylation constitutes a major mechanism of global regulation of the cyanobacterial metabolism under oxidative stress conditions.
    Mots-clés : Amino Acid Sequence, B2CYA, Bacterial Proteins, carbon metabolism, Cyanobacteria, cysteine modification, Glutathione Disulfide, glutathionylation, MICROBIO, mixed-disulfide bridge, Molecular Sequence Data, nitrogen metabolism, Peptide Fragments, Protein Processing, Post-Translational, Proteome, proteomics, redox regulation, Synechocystis.
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Publications entre 2012 et 2014

- P. Garcin, O. Delalande, J-Y. Zhang, C. Cassier-Chauvat, F. Chauvat and Y. Boulard 2012. A transcriptional-switch model for Slr1738-controlled gene expression in the cyanobacterium Synechocystis. BMC Structural Biol. 12:1

- M. Zaffagnini, M. Bedhomme, H. Groni, C.H. Marchand, C. Puppo, B. Gontero, C. Cassier-Chauvat, P. Decottignies, S.D. Lemaire 2012. Glutathionylation in the photosynthetic model Chlamydomonas reinhardtii : a proteomic survey Mol Cell Proteomics 11(2):M111.014142. doi : 10.1074/mcp.M111.014142.

- B. Soni, L. Houot, C. Cassier-Chauvat and F. Chauvat. 2012. Prominent role of the three Synechocystis PchR-like regulators in the defense against metal and oxidative stresses. Open J. Biochem. 1-1

- J. Dutheil, P. Saenkham, S. Sakr, C. Leplat, M. Ortega-Ramos, H. Bottin, L. Cournac, C. Cassier-Chauvat and F. Chauvat. 2012. The AbrB2 autorepressor, expressed from an atypical promoter, represses the hydrogenase operon to regulate hydrogen production in Synechocystis strain PCC6803. J. Bacteriol. 194 : 5423–33

- K. Narainsamy, C. Cassier-Chauvat, C. Junot and F. Chauvat. 2013. High performance analysis of the cyanobacterial metabolism via liquid chromatography coupled to a LTQ-Orbitrap mass spectrometer : evidence that glucose reprograms the whole carbon metabolism and triggers oxidative stress. Metabolomics. 9:21–32 DOI 10.1007/s11306-011-0382-4

- C. Leplat, R. Champeimont, P. Saenkham, C. Cassier-Chauvat, J-C Aude and F. Chauvat. 2013. Genome-wide transcriptome analysis of hydrogen production in the cyanobacterium Synechocystis : towards the identification of new players. Int. J. of Hydrogen Energy. 38 : 1866-72.

- T. Jittawuttipoka, M. Planchon, O. Spalla, K. Benzerara, F. Guyot, C. Cassier-Chauvat and F. Chauvat. 2013. Multidisciplinary evidences that Synechocystis PCC6803 exopolysaccharides operate in cell sedimentation and protection against salt and metal stresses. PLOS One Volume 8, Issue 2, e55564. . DOI : 10.1371/journal.pone.0055564

- M. Planchon, T. Jittawuttipoka, C. Cassier-Chauvat, F. Guyot, F. Chauvat and O. Spalla. 2013. Influence of exopolysaccharides on the electrophoretic properties of the model cyanobacterium Synechocystis. Colloids and Surfaces B : Biointerfaces 110 : 171– 177

- M. Planchon, T. Jittawuttipoka, C. Cassier-Chauvat, F. Guyot, A. Gelabert, M. F. Benedetti, F. Chauvat and O. Spalla. 2013. Exopolysaccharides protect Synechocystis against the deleterious effects of Titanium dioxide nanoparticles in natural and artificial waters. J. Colloid and Interface Science 405 : 35–43

- B. Marteyn, S. Sakr, S. Farci, M. Bedhomme, S. Chardonnet, P. Decottignies, S. Lemaire, C. Cassier-Chauvat and F. Chauvat. 2013. The Synechocystis PCC6803 MerA-like enzyme operates in the reduction of both mercury and uranium, under the control of the glutaredoxin 1 enzyme. J. Bacteriol. 195:4138-45

- S. Sakr, J. Dutheil, P. Saenkham, H. Bottin, C. Leplat, M. Ortega-Ramos, J-C. Aude, V. Chapuis, G. Guedeney, P. Decottignies, S. Lemaire, C. Cassier-Chauvat, and F. Chauvat. 2013. The activity of the Synechocystis PCC6803 AbrB2 regulator of hydrogen production can be post-translationally controlled through glutathionylation Int. J. Hydrogen Energy. 38 : 13547-13555

- M. Ortega-Ramos, T. Jittawuttipoka, P. Saenkham, A. Czarnecka-Kwasiborski, H. Bottin, C. Cassier-Chauvat and F. Chauvat. 2014. Engineering Synechocystis PCC6803 for hydrogen production : influence on the tolerance to oxidative and sugar stresses. PLOS One Volume 9, Issue 2, e89372 DOI : 10.1371/journal.pone.0089372

- S. Chardonnet, S. Sakr, C. Cassier-Chauvat, P. Le Maréchal, F. Chauvat, S. Lemaire and P. Decottignies 2014. First proteomic study of S-glutathionylation in cyanobacteria. J. Prot. Res.

- C. Cassier-Chauvat, T. Veaudor and F. Chauvat. 2014. Advances in the function and regulation of hydrogenase in the cyanobacterium Synechocystis PCC6803. Int. J. Mol. Sci 15 : 19938-19951 doi:10.3390/ijms151119938

- C. Cassier-Chauvat and F. Chauvat, 2014. Function and Regulation of Ferredoxins in the Cyanobacterium, Synechocystis PCC6803 : Recent Advances. Life (Basel) 2014, 4(4):666-680 doi:10.3390/life4040666

- C. Cassier-Chauvat, F. Chauvat, 2015. Responses to oxidative and heavy metal stresses in cyanobacteria : recent advances. Int J Mol Sci 2015, 16(1):871-886doi : 10.3390/ijms16010871

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