title: Proteomic and cellular views of Arthrospira sp. PCC 8005 adaptation to nitrogen depletion.
abstract: Cyanobacteria are photosynthetic prokaryotes that play a crucial role in the Earth's nitrogen and carbon cycles. Nitrogen availability is one of the most important factors in cyanobacterial growth. Interestingly, filamentous non-diazotrophic cyanobacteria, such as Arthrospira sp. PCC 8005, have developed survival strategies that enable them to adapt to nitrogen deprivation. Metabolic studies recently demonstrated a substantial synthesis and accumulation of glycogen derived from amino acids during nitrogen starvation. Nevertheless, the regulatory mechanism of this adaptation is poorly understood. To the best of our knowledge, this study is the first proteomic and cellular analysis of Arthrospira sp. PCC 8005 under nitrogen depletion. Label-free differential proteomic analysis indicated the global carbon and nitrogen reprogramming of the cells during nitrogen depletion as characterized by an upregulation of glycogen synthesis and the use of endogenous nitrogen sources. The degradation of proteins and cyanophycin provided endogenous nitrogen when exogenous nitrogen was limited. Moreover, formamides, cyanates and urea were also potential endogenous nitrogen sources. The transporters of some amino acids and alternative nitrogen sources such as ammonium permease 1 were induced under nitrogen depletion. Intriguingly, although Arthrospira is a non-diazotrophic cyanobacterium, we observed the upregulation of HetR and HglK proteins, which are involved in heterocyst differentiation. Moreover, after a long period without nitrate, only a few highly fluorescent cells in each trichome were observed, and they might be involved in the long-term survival mechanism of this non-diazotrophic cyanobacterium under nitrogen deprivation.
authors.affiliation: Department of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, B-7000 Mons, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Deschoenmaeker
authors.affiliation: Department of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, B-7000 Mons, Belgium.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Facchini
authors.affiliation: Department of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, B-7000 Mons, Belgium.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Leroy
authors.affiliation: Expert Group for Molecular and Cellular Biology MCB, Belgian Nuclear Research Center SCK.CEN, B-2400 Mol, Belgium.|Department of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, B-7000 Mons, Belgium.
authors.forename: Hanène
authors.initials: H
authors.lastname: Badri
authors.affiliation: Laboratoire de Chimie Bactérienne, CNRS-UMR 7283, Aix-Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors.forename: C-C
authors.initials: CC
authors.lastname: Zhang
authors.affiliation: Department of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, B-7000 Mons, Belgium.
authors.forename: Ruddy
authors.initials: R
authors.lastname: Wattiez
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D001426:Bacterial Proteins / Q000032:analysis*; D002244:Carbon / Q000378:metabolism; D003485:Cyanates / Q000378:metabolism; D005559:Formamides / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006003:Glycogen / Q000096:biosynthesis; D053858:Metabolic Networks and Pathways; D009584:Nitrogen / Q000378:metabolism*; D020543:Proteome / Q000032:analysis*; D040901:Proteomics; D053545:Spirulina / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D013312:Stress, Physiological; D014508:Urea / Q000378:metabolism
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D003485:Cyanates; D005559:Formamides; D020543:Proteome; D002244:Carbon; D014508:Urea; D006003:Glycogen; D009584:Nitrogen