Nonmetabolizable analogue of 2-oxoglutarate elicits heterocyst differentiation under repressive conditions in Anabaena sp. PCC 7120
| Autor: | Cheng-Cai Zhang, Sophie Laurent, Fabio Ziarelli, Han Chen, Sylvie Bédu, Ling Peng |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Cyanobacteria
Fluorine Radioisotopes Growth medium Multidisciplinary biology Nitrogen Anabaena Biological Sciences biology.organism_classification Polymerase Chain Reaction Citric acid cycle Heterocyst differentiation chemistry.chemical_compound Biochemistry chemistry Biophysics Ketoglutaric Acids Signal transduction Nuclear Magnetic Resonance Biomolecular Intracellular DNA Primers Signal Transduction Heterocyst |
| Zdroj: | Proceedings of the National Academy of Sciences. 102:9907-9912 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.0502337102 |
| Popis: | In response to combined nitrogen starvation in the growth medium, the filamentous cyanobacterium Anabaena sp. PCC 7120 is able to develop a particular cell type, called a heterocyst, specialized in molecular nitrogen fixation. Heterocysts are regularly intercalated among vegetative cells and represent 5–10% of all cells along each filament. In unicellular cyanobacteria, the key Krebs cycle intermediate, 2-oxoglutarate (2-OG), has been suggested as a nitrogen status signal, but in vivo evidence is still lacking. In this study we show that nitrogen starvation causes 2-OG to accumulate transiently within cells of Anabaena PCC 7120, reaching a maximal intracellular concentration of ≈0.1 mM 1 h after combined nitrogen starvation. A nonmetabolizable fluorinated 2-OG derivative, 2,2-difluoropentanedioic acid (DFPA), was synthesized and used to demonstrate the signaling function of 2-OG in vivo . DFPA is shown to be a structural analogue of 2-OG and the process of its uptake and accumulation in vivo can be followed by 19 F magic angle spinning NMR because of the presence of the fluorine atom and its chemical stability. DFPA at a threshold concentration of 0.3 mM triggers heterocyst differentiation under repressing conditions. The multidisciplinary approaches using synthetic fluorinated analogues, magic angle spinning NMR for their analysis in vivo , and techniques of molecular biology provide a powerful means to identify the nature of the signals that remain unknown or poorly defined in many signaling pathways. |
| Databáze: | OpenAIRE |
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