The utilization of molecular hydrogen by the blue-green alga Anabaena cylindrica

Bothe, Hermann; Tennigkeit, J.; Eisbrenner, G.

doi:10.1007/bf00429628

Cited by 121 publications

(50 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Hydrogen uptake in the dark depends on the presence of 02 as an electron acceptor, however, light-driven H2 uptake also has been reported for Anabaena (3,29). If N2-fixing filaments were incubated under 100%o H2 in the presence of the PSII inhibitor DCMU, H2 was evolved upon illumination ( Fig.…”

Section: Resultsmentioning

confidence: 64%

“…In heterocystous blue- ' Supported by the College of Agricultural and Life Sciences, University of Wisconsin-Madison, by National Science Foundation grant green algae, uptake hydrogenase is confined to heterocysts (22) where it can couple to O2 uptake and provide a source of ATP (21). Light-dependent H2 uptake also has been reported (28,29), and H2 can provide electrons for C2H2 reduction in the light (3). This report more closely examines the light and dark reactions of uptake hydrogenase in whole filaments, isolated heterocysts, and hydrogenase-containing particles.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Light and Dark Reactions of the Uptake Hydrogenase in Anabaena 7120

Houchins¹,

Burris²

1981

Plant Physiol.

View full text Add to dashboard Cite

Reactions of the uptake hydrogenase from Anabaena 7120 (A.T.C.C. 27893, Nostoc muscorum) were examined in whole filaments, isolated heterocysts, and membrane particles. Whole ifiaments or isolated heterocysts that contained nitrogenase consumed H2 in the presence of C2H2 or N2 in a light-dependent reaction. If nitrogenase was inactivated by O2 shock, filaments catalyzed H2 uptake to an unidentified endogenous acceptor in the light. Addition of N03-or N02-enhanced these rates. Isolated heterocysts consumed H2 in the dark in the presence of electron acceptors with positive midpoint potentials, and these reactions were not enhanced by light. With acceptors of negative midpoint potential, significant light enhancement of H2 uptake occurred. Maximum rates of light-dependent uptake were approximately 25% of the maximum dark rates observed. Membrane particles prepared from isolated heterocysts showed similar specificity for electron acceptors. These particles catalyzed a cyanidesensitive oxyhydrogen reaction that was inactivated by 02 at 02 concentrations above 2%. Light-dependent H2 uptake to low potential acceptors by these particles was inhibited by dibromothymoquinone but was insensitive to cyanide. In the presence of 02, light-dependent H2 uptake occurred sunultaneously with the oxyhydrogen reaction. The pH optima for both types of H2 uptake were near 7.0. These results further clarify the role of uptake hydrogenase in donating electrons to both the photosynthetic and respiratory electron transport chains of Anabaena.Uptake hydrogenases have been found in several aerobic N2-fixing organisms (1,6,12), and these enzymes share several common properties. They are membrane-bound (7,12,28), couple to 02 consumption via a Cyt-containing electron transport system, and through this reaction provide a source of ATP (7, 9, 21). Several authors have suggested that these uptake hydrogenases function to recycle the H2 evolved by nitrogenase (4,7,9,21).In blue-green algae, membrane-bound hydrogenases can couple to two different electron transport pathways. Peschek has demonstrated respiratory H2 uptake and photosynthetic H2 uptake in Anacystis nidulans (19,20) in which the hydrogenase was induced by growth under a gas phase containing H2. In the dark, both H2 uptake systems could react only with acceptors having a positive midpoint potential; however, upon illumination acceptors with a negative potential could also be reduced.

show abstract

Section: Resultsmentioning

confidence: 64%

mentioning

confidence: 99%

Light and Dark Reactions of the Uptake Hydrogenase in Anabaena 7120

Houchins¹,

Burris²

1981

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…The activity of the endogenous bidirectional [NiFe] hydrogenase of S. elongatus to uptake H 2 and reduce NAD þ has been examined in cell extracts and determined to be very low (85 nmol h −1 · mg protein −1 ) (37). Although this level of activity is sufficient to fix carbon, increase starch accumulation, or support nitrogenase activity (32,38) it is thought that this rate is insufficient to support autochemolithic growth using H 2 as a reductant, and H 2 -dependent cell division has not been observed in cyanobacteria (37,39) (Fig. 3A).…”

Section: Resultsmentioning

confidence: 99%

Rewiring hydrogenase-dependent redox circuits in cyanobacteria

Ducat

Sachdeva

Silver

2011

Proc. Natl. Acad. Sci. U.S.A.

115

View full text Add to dashboard Cite

Hydrogenases catalyze the reversible reaction 2H þ þ 2e − ↔ H 2 with an equilibrium constant that is dependent on the reducing potential of electrons carried by their redox partner. To examine the possibility of increasing the photobiological production of hydrogen within cyanobacterial cultures, we expressed the [FeFe] hydrogenase, HydA, from Clostridium acetobutylicum in the nonnitrogen-fixing cyanobacterium Synechococcus elongatus sp. 7942. We demonstrate that the heterologously expressed hydrogenase is functional in vitro and in vivo, and that the in vivo hydrogenase activity is connected to the light-dependent reactions of the electron transport chain. Under anoxic conditions, HydA activity is capable of supporting light-dependent hydrogen evolution at a rate >500-fold greater than that supported by the endogenous [NiFe] hydrogenase. Furthermore, HydA can support limited growth solely using H 2 and light as the source of reducing equivalents under conditions where Photosystem II is inactivated. Finally, we demonstrate that the addition of exogenous ferredoxins can modulate redox flux in the hydrogenase-expressing strain, allowing for greater hydrogen yields and for dark fermentation of internal energy stores into hydrogen gas.biofuel | metabolic engineering

show abstract

“…In some filamentous strains, it is particularly expressed in the nitrogen-fixing heterocysts with little or no activity in the photosynthetic vegetative cells (see "Transcription of hupSL" below) (39,87,88,152). The recycling of hydrogen produced by nitrogenase has been suggested to have at least three beneficial functions for the organism: (i) it provides the organism with ATP via the oxyhydrogen (Knallgas) reaction; (ii) it removes oxygen from nitrogenase, thereby protecting it from inactivation; and (iii) it supplies reducing equivalents (electrons) to nitrogenase and for other cell functions (32,33,90,183,216).…”

Section: Cyanobacterial Uptake Hydrogenasesmentioning

confidence: 99%

Hydrogenases and Hydrogen Metabolism of Cyanobacteria

Tamagnini

Axelsson

Lindberg

et al. 2002

Microbiol Mol Biol Rev

467

372

View full text Add to dashboard Cite

Cyanobacteria may possess several enzymes that are directly involved in dihydrogen metabolism: nitrogenase(s) catalyzing the production of hydrogen concomitantly with the reduction of dinitrogen to ammonia, an uptake hydrogenase (encoded by hupSL) catalyzing the consumption of hydrogen produced by the nitrogenase, and a bidirectional hydrogenase (encoded by hoxFUYH) which has the capacity to both take up and produce hydrogen. This review summarizes our knowledge about cyanobacterial hydrogenases, focusing on recent progress since the first molecular information was published in 1995. It presents the molecular knowledge about cyanobacterial hupSL and hoxFUYH, their corresponding gene products, and their accessory genes before finishing with an applied aspect—the use of cyanobacteria in a biological, renewable production of the future energy carrier molecular hydrogen. In addition to scientific publications, information from three cyanobacterial genomes, the unicellular Synechocystis strain PCC 6803 and the filamentous heterocystous Anabaena strain PCC 7120 and Nostoc punctiforme (PCC 73102/ATCC 29133) is included

show abstract

The utilization of molecular hydrogen by the blue-green alga Anabaena cylindrica

Cited by 121 publications

References 23 publications

Light and Dark Reactions of the Uptake Hydrogenase in Anabaena 7120

Light and Dark Reactions of the Uptake Hydrogenase in Anabaena 7120

Rewiring hydrogenase-dependent redox circuits in cyanobacteria

Hydrogenases and Hydrogen Metabolism of Cyanobacteria

Contact Info

Product

Resources

About