An increase in the level of 2-oxoglutarate promotes heterocyst development in the cyanobacterium Anabaena sp. strain PCC 7120

Li, Jianhong; Laurent, Sophie; Konde, V. B.; Bédu, Sylvie; Zhang, Cheng‐Cai

doi:10.1099/mic.0.26462-0

Cited by 53 publications

(50 citation statements)

References 38 publications

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“…Expression of hetR is upregulated by nitrogen deprivation, and this upregulation depends on NtcA (62). Heterocyst formation is also controlled by the availability of 2-oxoglutarate, which provides the carbon skeleton for the incorporation of inorganic nitrogen and which also serves as a signal molecule of the organic carbon content in the developing heterocysts (122,161,223). NtcA is the main 2-oxoglutarate sensor for the initiation of heterocyst differentiation (239).…”

Section: Occurrence Of Nitrogenases In Heterocystsmentioning

confidence: 99%

Nitrogen Fixation and Hydrogen Metabolism in Cyanobacteria

Bothe

Schmitz²,

Yates

et al. 2010

Microbiol Mol Biol Rev

365

222

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SUMMARY This review summarizes recent aspects of (di)nitrogen fixation and (di)hydrogen metabolism, with emphasis on cyanobacteria. These organisms possess several types of the enzyme complexes catalyzing N2 fixation and/or H2 formation or oxidation, namely, two Mo nitrogenases, a V nitrogenase, and two hydrogenases. The two cyanobacterial Ni hydrogenases are differentiated as either uptake or bidirectional hydrogenases. The different forms of both the nitrogenases and hydrogenases are encoded by different sets of genes, and their organization on the chromosome can vary from one cyanobacterium to another. Factors regulating the expression of these genes are emerging from recent studies. New ideas on the potential physiological and ecological roles of nitrogenases and hydrogenases are presented. There is a renewed interest in exploiting cyanobacteria in solar energy conversion programs to generate H2 as a source of combustible energy. To enhance the rates of H2 production, the emphasis perhaps needs not to be on more efficient hydrogenases and nitrogenases or on the transfer of foreign enzymes into cyanobacteria. A likely better strategy is to exploit the use of radiant solar energy by the photosynthetic electron transport system to enhance the rates of H2 formation and so improve the chances of utilizing cyanobacteria as a source for the generation of clean energy.

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Section: Occurrence Of Nitrogenases In Heterocystsmentioning

confidence: 99%

Nitrogen Fixation and Hydrogen Metabolism in Cyanobacteria

Bothe

Schmitz²,

Yates

et al. 2010

Microbiol Mol Biol Rev

365

222

View full text Add to dashboard Cite

show abstract

“…The latter conditions mimic, to some extent, nitrogen starvation in Anabaena sp. PCC 7120 (Li et al, 2003;Laurent et al, 2005;Chen et al, 2006). Interestingly, 2-OG and both its analogues also trigger Ca 2+ transients in Anabaena similar to the ones observed in S. elongatus (F. Leganes and F. FernandezPiñas, unpublished results).…”

Section: Discussionmentioning

confidence: 63%

Role of calcium in acclimation of the cyanobacterium Synechococcus elongatus PCC 7942 to nitrogen starvation

2009

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A Ca2+ signal is required for the process of heterocyst differentiation in the filamentous diazotrophic cyanobacterium Anabaena sp. PCC 7120. This paper presents evidence that a transient increase in intracellular free Ca2+ is also involved in acclimation to nitrogen starvation in the unicellular non-diazotrophic cyanobacterium Synechococcus elongatus PCC 7942. The Ca2+ transient was triggered in response to nitrogen step-down or the addition of 2-oxoglutarate (2-OG), or its analogues 2,2-difluoropentanedioic acid (DFPA) and 2-methylenepentanedioic acid (2-MPA), to cells growing with combined nitrogen, suggesting that an increase in intracellular 2-OG levels precedes the Ca2+ transient. The signalling protein PII and the transcriptional regulator NtcA appear to be needed to trigger the signal. Suppression of the Ca2+ transient by the intracellular Ca2+ chelator N,N′-[1,2-ethanediylbis(oxy-2,1-phenylene)]bis[N-[2-[(acetyloxy)methoxy]-2-oxoethyl]]-,bis[(acetyloxy)methyl] ester (BAPTA-AM) inhibited expression of the glnB and glnN genes, which are involved in acclimation to nitrogen starvation and transcriptionally activated by NtcA. BAPTA-AM treatment partially inhibited expression of the nblA gene, which is involved in phycobiliprotein degradation following nutrient starvation and is regulated by NtcA and NblR; in close agreement, BAPTA-AM treatment partially inhibited bleaching following nitrogen starvation. Taken together, the results presented here strongly suggest an involvement of a defined Ca2+ transient in acclimation of S. elongatus to nitrogen starvation through NtcA-dependent regulation.

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“…The resulting fragment was cloned under the control of the petE promoter of the pSKpetE plasmid [15]. Plasmids expressing dimeric (+) or (-) ASBVd were selected after the sequencing procedure (Millegen, France).…”

Section: Construction Of Nostoc/asbvd Recombinant Strainsmentioning

confidence: 99%

“…Plasmids expressing dimeric (+) or (-) ASBVd were selected after the sequencing procedure (Millegen, France). The petEASBVd fragments were then subcloned into the pRL25 plasmid [15] after performing a linearization step using the NotI and KpnI enzymes. The resulting plasmids were sequenced in order to further confirm the (+) or (-) orientation of the viroid.…”

Section: Construction Of Nostoc/asbvd Recombinant Strainsmentioning

confidence: 99%