Simultaneous Occurrence of Two Different Glyceraldehyde-3-Phosphate Dehydrogenases in Heterocystous N2-Fixing Cyanobacteria

Valverde, Federico; Peleato, M. Luisa; Fillat, Marı́a F.; Gómez‐Moreno, Carlos; Losada, M.; Serrano, Aurelio

doi:10.1006/bbrc.2001.4782

Cited by 9 publications

(6 citation statements)

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“…This observation is similar to a previous finding that Synechocystis PCC 6803 Gap2 is present in multiple growth conditions, with maximum activity in photoautotrophic conditions [88]. Downregulation of gap2 in heterocysts (Figure 7) also supports a previous report that Gap2 is less abundant in heterocysts than in vegetative cells of A. variabilis [89]. However, whereas Valverde et al [89] detected gap3 transcripts in heterocysts and vegetative cells of A. variabilis , but none of gap1 , we found the opposite (Additional file 7).…”

Section: Resultssupporting

confidence: 91%

“…Downregulation of gap2 in heterocysts (Figure 7) also supports a previous report that Gap2 is less abundant in heterocysts than in vegetative cells of A. variabilis [89]. However, whereas Valverde et al [89] detected gap3 transcripts in heterocysts and vegetative cells of A. variabilis , but none of gap1 , we found the opposite (Additional file 7). …”

Section: Resultssupporting

confidence: 89%

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Cell-specific gene expression in Anabaena variabilis grown phototrophically, mixotrophically, and heterotrophically

et al. 2013

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BackgroundWhen the filamentous cyanobacterium Anabaena variabilis grows aerobically without combined nitrogen, some vegetative cells differentiate into N2-fixing heterocysts, while the other vegetative cells perform photosynthesis. Microarrays of sequences within protein-encoding genes were probed with RNA purified from extracts of vegetative cells, from isolated heterocysts, and from whole filaments to investigate transcript levels, and carbon and energy metabolism, in vegetative cells and heterocysts in phototrophic, mixotrophic, and heterotrophic cultures.ResultsHeterocysts represent only 5% to 10% of cells in the filaments. Accordingly, levels of specific transcripts in vegetative cells were with few exceptions very close to those in whole filaments and, also with few exceptions (e.g., nif1 transcripts), levels of specific transcripts in heterocysts had little effect on the overall level of those transcripts in filaments. In phototrophic, mixotrophic, and heterotrophic growth conditions, respectively, 845, 649, and 846 genes showed more than 2-fold difference (p < 0.01) in transcript levels between vegetative cells and heterocysts. Principal component analysis showed that the culture conditions tested affected transcript patterns strongly in vegetative cells but much less in heterocysts. Transcript levels of the genes involved in phycobilisome assembly, photosynthesis, and CO2 assimilation were high in vegetative cells in phototrophic conditions, and decreased when fructose was provided. Our results suggest that Gln, Glu, Ser, Gly, Cys, Thr, and Pro can be actively produced in heterocysts. Whether other protein amino acids are synthesized in heterocysts is unclear. Two possible components of a sucrose transporter were identified that were upregulated in heterocysts in two growth conditions. We consider it likely that genes with unknown function represent a larger fraction of total transcripts in heterocysts than in vegetative cells across growth conditions.ConclusionsThis study provides the first comparison of transcript levels in heterocysts and vegetative cells from heterocyst-bearing filaments of Anabaena. Although the data presented do not give a complete picture of metabolism in either type of cell, they provide a metabolic scaffold on which to build future analyses of cell-specific processes and of the interactions of the two types of cells.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-14-759) contains supplementary material, which is available to authorized users.

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Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 89%

Cell-specific gene expression in Anabaena variabilis grown phototrophically, mixotrophically, and heterotrophically

et al. 2013

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“…Heterocysts rely on energy provided by vegetative cells in the form of sucrose, since they cannot generate reducing equivalents through photosynthesis. This sugar is metabolized in heterocysts generating glucose-6 phosphate (G6P), which represents the major source of reducing equivalents in these cells and is subsequently degraded through the OPPP (Figure 5) [140,418,419]. The OPPP is the main energy metabolic pathway and the predominant route for the degradation of G6P in heterocysts, although the Krebs cycle and, to a lesser extent, the glycolysis pathway can also provide some reducing equivalents.…”

Section: Energy Metabolism and Metabolic Network In The Diazotropmentioning

confidence: 99%

“…These cells express an NAD(H)- and an NADP(H)-dependent G3P dehydrogenase that exhibit different abundances and perform different metabolic functions [417,419,420,421]. The NAD(H)-dependent enzyme is the most abundant and, despite carrying out both reactions, preferentially catalyzes the gluconeogenesis reaction, while the NADP(H)-dependent enzyme preferentially carries out the glycolytic route generating NADPH but provides a lower contribution to the net reaction [419]. This also illustrates that heterocysts preferentially use NADH for the anabolic reaction, while NADPH is favored for Fd reduction and N 2 fixation [419].…”

Section: Energy Metabolism and Metabolic Network In The Diazotropmentioning

confidence: 99%

“…The NAD(H)-dependent enzyme is the most abundant and, despite carrying out both reactions, preferentially catalyzes the gluconeogenesis reaction, while the NADP(H)-dependent enzyme preferentially carries out the glycolytic route generating NADPH but provides a lower contribution to the net reaction [419]. This also illustrates that heterocysts preferentially use NADH for the anabolic reaction, while NADPH is favored for Fd reduction and N 2 fixation [419]. Thus, the presence of two enzymes enables heterocysts to use the OPPP-derived G3P preferentially for G6P regeneration, while the lower glycolysis pathway, despite being hampered, is not completely abolished and can generate pyruvate to some extent (Figure 5).…”

Section: Energy Metabolism and Metabolic Network In The Diazotropmentioning

confidence: 99%

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Metalloproteins in the Biology of Heterocysts

Pernil

Schleiff

2019

Life

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Cyanobacteria are photoautotrophic microorganisms present in almost all ecologically niches on Earth. They exist as single-cell or filamentous forms and the latter often contain specialized cells for N2 fixation known as heterocysts. Heterocysts arise from photosynthetic active vegetative cells by multiple morphological and physiological rearrangements including the absence of O2 evolution and CO2 fixation. The key function of this cell type is carried out by the metalloprotein complex known as nitrogenase. Additionally, many other important processes in heterocysts also depend on metalloproteins. This leads to a high metal demand exceeding the one of other bacteria in content and concentration during heterocyst development and in mature heterocysts. This review provides an overview on the current knowledge of the transition metals and metalloproteins required by heterocysts in heterocyst-forming cyanobacteria. It discusses the molecular, physiological, and physicochemical properties of metalloproteins involved in N2 fixation, H2 metabolism, electron transport chains, oxidative stress management, storage, energy metabolism, and metabolic networks in the diazotrophic filament. This provides a detailed and comprehensive picture on the heterocyst demands for Fe, Cu, Mo, Ni, Mn, V, and Zn as cofactors for metalloproteins and highlights the importance of such metalloproteins for the biology of cyanobacterial heterocysts.

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A single gene all3940 (Dps) overexpression in Anabaena sp. PCC 7120 confers multiple abiotic stress tolerance via proteomic alterations

Narayan

Kumari

Bhargava

et al. 2015

Funct Integr Genomics

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DNA-binding proteins (Dps) induced during starvation play an important role in gene regulation and maintaining homeostasis in bacteria. The nitrogen-fixing cyanobacterium, Anabaena PCC7120, has four genes annotated as coding for Dps; however, the information on their physiological roles is limiting. One of the genes coding for Dps, 'all3940' was found to be induced under different abiotic stresses in Anabaena and upon overexpression enhanced the tolerance of Anabaena to a multitude of stresses, which included salinity, heat, heavy metals, pesticide, and nutrient starvation. On the other hand, mutation in the gene resulted in decreased growth of Anabaena. The modulation in the levels of All3940 in Anabaena, achieved either by overexpression of the protein or mutation of the gene, resulted in changes in the proteome, which correlated well with the physiological changes observed. Proteins required for varied physiological activities, such as photosynthesis, carbon-metabolism, oxidative stress alleviation, exhibited change in protein profile upon modulation of All3940 levels in Anabaena. This suggested a direct or an indirect effect of All3940 on the expression of the above stress-responsive proteins, thereby enhancing tolerance in Anabaena PCC7120. Thus, All3940, though categorized as a Dps, is possibly a general stress protein having a global role in regulating tolerance to multitude of stresses in Anabaena.

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Simultaneous Occurrence of Two Different Glyceraldehyde-3-Phosphate Dehydrogenases in Heterocystous N2-Fixing Cyanobacteria

Cited by 9 publications

References 30 publications

Cell-specific gene expression in Anabaena variabilis grown phototrophically, mixotrophically, and heterotrophically

Cell-specific gene expression in Anabaena variabilis grown phototrophically, mixotrophically, and heterotrophically

Metalloproteins in the Biology of Heterocysts

A single gene all3940 (Dps) overexpression in Anabaena sp. PCC 7120 confers multiple abiotic stress tolerance via proteomic alterations

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