Nitrogenase activity in extracts of heterocystous and non-heterocystous blue-green algae

Haystead, A.; Robinson, Rebekah J.; Stewart, W. D. P.

doi:10.1007/bf00408884

Cited by 94 publications

(35 citation statements)

References 15 publications

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“…Using a standard double-reciprocal plot, the K, for acetylene of the partially purified enzyme was found to be 1.8 x atmospheres. This is within the range (2 x 10-3-6 x lop3 atm, 1 atm = 101 325 N mp2) previously reported [4] and is consistent with values obtained with bacterial nitrogenases. However, the K, for acetylene determined with cultures of A .…”

Section: Properties Of Anabaena Nitrogenasesupporting

confidence: 92%

“…It should be noted that even in the early stages of purification, the Fe component from A . cylindrica is oxygen-sensitive [4].…”

Section: Purification Of Anabaena Nitrogenasementioning

confidence: 99%

“…Like bacterial nitrogenases, the cyanobacterial nitrogenase is composed of two components [14,15] requires ATP, Mg2+, and reductant [4], couples with ferredoxin [16], and contains active center iron and sulfide groups [13]. Previous studies have used crude extracts, and both nitrogenase specific activity, 0.83 -2.5 nm acetylene reduced x min-' x mg protein-' [4,13,14,16] and total recovery of whole-cell activity, about 20%, have been rather low. Further studies of the biochemistry and physiology of nitrogen-fixation in these organisms require high activity extracts, and the purification of the enzyme.…”

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confidence: 99%

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Purification and Properties of Nitrogenase from the Cyanobacterium, Anabaena cylindrica

Hallenbeck

Kostel

Benemann

1979

European Journal of Biochemistry

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The nitrogenase complex was isolated from nitrogen-starved cultures of Anabaena cylindrica. Sodium dithionite, photochemically reduced ferredoxin, and NADPH were found to be effective electron donors to nitrogenase in crude extracts whereas hydrogen and pyruvate were not. The K , for acetylene in vivo is ten-fold higher than the K,,, in vitro, whereas this pattern does not hold for the non-heterocystous cyanobacterium, Plectonema boryanum. This indicates that at least one mechanism of oxygen protection in vivo involves a gas diffusion barrier presented by the heterocyst cell wall. The Mo-Fe component was purified to homogeneity. Its molecular weight (220000), subunit composition, isoelectric point (4.8), Mo, Fe, and S2-content (2,20 and 20 mol/mol component), and amino acid composition indicate that this component has similar properties to Mo-Fe-containing components isolated from other bacterial sources. The isolated components from A . cylindrica were found to cross-react, to varying degrees, with components isolated from Azotobacter vinelandii, Rhodospirillum rubvum, and P. boryanum.The presence of nitrogenase, the enzyme that catalyzes biological fixation of atmospheric nitrogen, has been described in a variety of prokaryotic organisms, including some species of cyanobacteria [I -51. Enzyme activity has invariably been found to be dependent on a source of ATP and reductant, and to be irreversibly inactivated by oxygen. Most of the cyanobacteria known to fix nitrogen belong to filamentous, heterocyst-forming families which are capable of fixing nitrogen under aerobic conditions. The cyanobacterial nitrogenase is thought to be localized in these heterocysts, specialized differentiated cells which have a restricted photosynthetic process that does not evolve oxygen, due to the absence of photosystem I1 components. The thick cell wall structure of heterocysts is postulated to provide protection from oxygen inactivation by serving as an effective barrier to the diffusion of gases [6,7].Nitrogenase activity in vivo is maximal only in the light, indicating dependence on photosystem I but is not directly dependent on photosystem I1 activity [8,9]. Thus, the major pathways for supply of reductant (reduced ferredoxin) probably involve the metab- Enzymes. Nitrogenase or nitrogen: (acceptor) oxidoreductase (EC 1.7.99.2): creatine phosphokinase (EC 2.7.3.2).

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Section: Properties Of Anabaena Nitrogenasesupporting

confidence: 92%

“…It should be noted that even in the early stages of purification, the Fe component from A . cylindrica is oxygen-sensitive [4].…”

Section: Purification Of Anabaena Nitrogenasementioning

confidence: 99%

mentioning

confidence: 99%

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Purification and Properties of Nitrogenase from the Cyanobacterium, Anabaena cylindrica

Hallenbeck

Kostel

Benemann

1979

European Journal of Biochemistry

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“…Aerobic bacteria associated with microalgae have been proven to stimulate algal growth by removal/consumption of oxygen in the microenvironment, thereby creating more favorable conditions for photosynthesis (Mouget, 1995). High concentrations of oxygen also negatively affect nitrogen-fixation in cyanobacteria as the nitrogenase enzyme system is highly sensitive to oxygen (Haystead et al, 1970). For biofuelproducing cyanobacteria, which have nitrogen-fixing ability, a lower oxygen concentration would be favorable for nitrogen fixation.…”

Section: Bacterial Modification Of the Microalgal Environmentmentioning

confidence: 99%

Effects of bacterial communities on biofuel-producing microalgae: stimulation, inhibition and harvesting

Wang

Hill

Zheng

et al. 2014

Critical Reviews in Biotechnology

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Despite the great interest in microalgae as a potential source of biofuel to substitute for fossil fuels, little information is available on the effects of bacterial symbionts in mass algal cultivation systems. The bacterial communities associated with microalgae are a crucial factor in the process of microalgal biomass and lipid production and may stimulate or inhibit growth of biofuel-producing microalgae. In addition, we discuss here the potential use of bacteria to harvest biofuel-producing microalgae. We propose that aggregation of microalgae by bacteria to achieve 490% reductions in volume followed by centrifugation could be an economic approach for harvesting of biofuel-producing microalgae. Our aims in this review are to promote understanding of the effects of bacterial communities on microalgae and draw attention to the importance of this topic in the microalgal biofuel field.

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“…A characteristic of some N2-fixing blue-green algae such as Anabaena cylindrica is the presence of 'heterocysts', specialized cells that lack an 02-evolving photosystem activity (Thomas, 1970). These specialized cells have been shown to contain a nitrogenase system, which can catalyse ATP-dependent production of H2, in addition to containing a large part of the hydrogenase activity (Haystead et al, 1970;Tel-Or & Packer, 1976). However, the nature of oxygen toxicity and the mechanism of protecting the oxygen-labile components are not understood.…”

mentioning

confidence: 99%

Superoxide dismutase and catalase in the protection of the proton-donating systems of nitrogen fixation in the blue-green alga Anabaena cylindrica

Henry¹,

Гоготов²,

Hall³

1978

Biochemical Journal

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1. Superoxide dismutasel activity was present in the heterocysts and vegetative cells of Anabaena cylindrica, but was always lower in the heterocysts. 2. No qualitative differences were found in the superoxide dismutase from the two cellular types. 3. Catalase activity was also present in both cellular types. 4. Most of the NADP reductase activity, as assayed with menadione or ferredoxin as electron acceptor, was localized within the heterocysts. 5. Studies on H2 consumption showed that most of the hydrogenase activity was associated with the heterocysts. 6. The results are discussed in terms of the postulate that superoxide dismutase and catalase are involved in the protection of the protondonating systems participating in N2 fixation and H2 metabolism of heterocysts.

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Nitrogenase activity in extracts of heterocystous and non-heterocystous blue-green algae

Cited by 94 publications

References 15 publications

Purification and Properties of Nitrogenase from the Cyanobacterium, Anabaena cylindrica

Purification and Properties of Nitrogenase from the Cyanobacterium, Anabaena cylindrica

Effects of bacterial communities on biofuel-producing microalgae: stimulation, inhibition and harvesting

Superoxide dismutase and catalase in the protection of the proton-donating systems of nitrogen fixation in the blue-green alga Anabaena cylindrica

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