Acetylene reduction (nitrogen fixation) by cyanobacteria grown under alternating light-dark cycles

Millineaux, Philip M.; Gallon, John; Chaplin, Alan E.

doi:10.1111/j.1574-6968.1981.tb06249.x

Cited by 103 publications

(32 citation statements)

References 7 publications

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“…In filamentous, N 2 -fixing cyanobacteria of Sections IV and V the percentage of CphA2-like proteins was high, at 71.4 and 81.8 %, respectively. In comparison, only 8.4 % of Section I cyanobacteria possessed an additional CphA2-like protein, including three Cyanothece and one Gloeocapsa species that grow diazotrophically (Bandyopadhyay et al, 2013;Millineaux et al, 1981). CphA-coding ORFs of the sequenced species are summarized in Table S3.…”

Section: Distribution Of Cyanophycin Synthetases Amongst Cyanobacteriamentioning

confidence: 99%

CphA2 is a novel type of cyanophycin synthetase in N2-fixing cyanobacteria

et al. 2016

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Most cyanobacteria use a single type of cyanophycin synthetase, CphA1, to synthesize the nitrogen-rich polymer cyanophycin. The genomes of many N 2 -fixing cyanobacteria contain an additional gene that encodes a second type of cyanophycin synthetase, CphA2. The potential function of this enzyme has been debated due to its reduced size and the lack of one of the two ATP-binding sites that are present in CphA1. Here, we analysed CphA2 from Anabaena variabilis ATCC 29413 and Cyanothece sp. PCC 7425. We found that CphA2 polymerized the dipeptide b-aspartyl-arginine to form cyanophycin. Thus, CphA2 represents a novel type of cyanophycin synthetase. A cphA2 disruption mutant of A. variabilis was generated. Growth of this mutant was impaired under high-light conditions and nitrogen deprivation, suggesting that CphA2 plays an important role in nitrogen metabolism under N 2 -fixing conditions. Electron micrographs revealed that the mutant had fewer cyanophycin granules, but no alteration in the distribution of granules in its cells was observed. Localization of CphA2 by immunogold electron microscopy demonstrated that the enzyme is attached to cyanophycin granules. Expression of CphA1 and CphA2 was examined in Anabaena WT and cphA mutant cells. Whilst the CphA1 level increased upon nitrogen deprivation, the CphA2 level remained nearly constant.

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Section: Distribution Of Cyanophycin Synthetases Amongst Cyanobacteriamentioning

confidence: 99%

CphA2 is a novel type of cyanophycin synthetase in N2-fixing cyanobacteria

et al. 2016

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“…When comparing the N # fixation pattern of Symploca with that of other cyanobacteria it becomes evident that it differs from heterocystous cyanobacteria such as Anabaena cylindrica and the non-heterocystous Trichodesmium (Saino & Hattori, 1978 ;Capone et al, 1990Capone et al, , 1997 by having a long lag phase before activity in light commences and by performing a substantial proportion of the total daily N # fixation during the dark period. Other non-heterocystous species such as the unicellular Gloeothece (Mullineaux et al, 1981) and the filamentous Oscillatoria (Stal & Heyer, 1987) initiate N # fixation in the dark and perform N # fixation primarily in the absence of light. Under certain growth and nutrient conditions however, Gloeothece performs nitrogenase activity in the light even during light\dark cycles (Ortega-Calvo & Stal, 1991 ;Du & Gallon, 1993 ;Ortega-Calvo & Stal, 1994).…”

Section: mentioning

confidence: 99%

“…Most cyanobacteria capable of N # fixation do so under microaerobic or anaerobic conditions (Rippka & Waterbury, 1977). Gloeothece (Mullineaux, Gallon & Chaplin, 1981), Cyanothece (Schneegurt et al, 1994) and Oscillatoria (Stal & Heyer, 1987) all separate N # fixation and photosynthesis in time, fixing N # mainly during the dark period of a light\dark cycle. Heterocystous cyanobacteria, which possess cells specialized for N # fixation, confine most of their N # fixation to periods when solar energy or artificial light is available (Griffiths, Gallon & Chaplin, 1987 ;Ernst et al, 1990).…”

Section: mentioning

confidence: 99%

Aerobic nitrogen fixation is confined to a subset of cells in the non‐heterocystous cyanobacterium Symploca PCC 8002

et al. 1998

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Symploca PCC 8002 Ku$ tzing is a filamentous cyanobacterium that lacks the specialized cells, known as heterocysts, that protect nitrogenase from O # in most aerobic N # -fixing cyanobacteria. Nevertheless, Symploca is able to carry out N # fixation in the light under aerobic conditions. When cultures were grown under light\dark cycles, nitrogenase activity commenced and increased in the light phase and declined towards zero in the dark. Immunolocalization of dinitrogenase reductase in sectioned Symploca trichomes showed that the enzyme was present only in 9 % of the cells. These cells lacked any obvious mechanical protection against atmospheric O # and their ultrastructural characteristics were similar to those of cells that did not contain any dinitrogenase reductase. The nitrogenase-containing cells possessed carboxysomes that were rich in ribulose-1,5-bisphosphate carboxylase\oxygenase and phycoerythrin, a light harvesting pigment of PS II. This indicates that these cells had a capacity for both N # fixation and photosynthesis. The significance of the localization pattern for dinitrogenase reductase is discussed in the context of N # fixation in Symploca PCC 8002.

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“…Most studies on dinitrogen fixation by cyanobacteria have been conducted under a regime of constant light. However, Mullineaux, Gallon & Chaplin (1981) reported that the unicellular (and hence nonheterocystous) species, Gloeothece sp. CCAP 1430/3, when subjected to an alternating cycle of 12 h light and 12 h darkness, fixed nitrogen almost exclusively in the dark period.…”

Section: Introductionmentioning

confidence: 99%

THE DIURNAL PATTERN OF DINITROGEN FIXATION BY CYANOBACTERIA IN SITU

1987

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SUMMARYThe diurnal patterns of cyanobacterial acetylene reduction (nitrogen fixation) and seasonal variations in these patterns were investigated in situ on a salt marsh and in a limestone cave. In the field, the non-heterocystous species fixed Ng mainly at night, while heterocystous species fixed Ng mainly during the day. These basic patterns could he infiuenced hy environmental conditions such as O^ availability and temperature. No acetylene reduction was observed in December, January or February.

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Acetylene reduction (nitrogen fixation) by cyanobacteria grown under alternating light-dark cycles

Cited by 103 publications

References 7 publications

CphA2 is a novel type of cyanophycin synthetase in N2-fixing cyanobacteria

CphA2 is a novel type of cyanophycin synthetase in N2-fixing cyanobacteria

Aerobic nitrogen fixation is confined to a subset of cells in the non‐heterocystous cyanobacterium Symploca PCC 8002

THE DIURNAL PATTERN OF DINITROGEN FIXATION BY CYANOBACTERIA IN SITU

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