Regulation of Nitrogenase Activity in the Anoxygenic Phototrophic Bacteria

Zumft, Walter G.

doi:10.1007/978-94-009-5175-4_76

Cited by 12 publications

(5 citation statements)

References 80 publications

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“…This is an energy-demanding process, theoretically consuming at least 16 ATP molecules for each N2 molecule reduced. It is not surprising that the nitrogenase system is highly regulated at both the gene expression level (8) and the posttranslational level (23,38).…”

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Posttranslational regulatory system for nitrogenase activity in Azospirillum spp

Hartmann

Lowery

et al. 1989

J Bacteriol

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The mechanism for "NH4+ switch-off/on" of nitrogenase activity in Azospirillum brasilense and A. lipoferum was investigated. A [39]) has been well studied in the purple nonsulfur photosynthetic bacterium Rhodospirillum rubrum. In R. rubrum, the loss of cellular nitrogenase activity during switch-off by NH4Cl is correlated with the covalent modification and resulting inactivation of dinitrogenase reductase (13). The covalent modification consists of the ADP-ribosylation of dinitrogenase reductase at . This reaction is catalyzed by dinitrogenase reductase ADP-ribosyltransferase (DRAT) (18,19). Dinitrogenase reductase is composed of two identical subunits, and the ADP-ribosylated subunit migrates more slowly than the unmodified subunit during sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Dinitrogenase reductase-activating glycohydrolase (DRAG) catalyzes the removal of the ADP-ribose group from the inactive dinitrogenase reductase, thereby reactivating the dinitrogenase reductase (20,31,32

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confidence: 99%

Posttranslational regulatory system for nitrogenase activity in Azospirillum spp

Hartmann

Lowery

et al. 1989

J Bacteriol

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“…Besides the multiple regulation of nif gene expression by nitrogen compounds, oxygen, and temperature (25), the nitrogenase activity itself can be regulated precisely. In a variety of N2-fixing bacteria, the addition of ammonium chloride causes a rapid and reversible inhibition of nitrogenase activity (15,27,37). In some phototrophic bacteria (37) and in Azospirillum brasilense and A. lipoferum (8), a covalent modification of the nitrogenase reductase (Fe protein) causes a reversible inhibition of nitrogenase activity when low concentrations of ammonium chloride are added (NH4' switch off).…”

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confidence: 99%

“…In a variety of N2-fixing bacteria, the addition of ammonium chloride causes a rapid and reversible inhibition of nitrogenase activity (15,27,37). In some phototrophic bacteria (37) and in Azospirillum brasilense and A. lipoferum (8), a covalent modification of the nitrogenase reductase (Fe protein) causes a reversible inhibition of nitrogenase activity when low concentrations of ammonium chloride are added (NH4' switch off). In Rhodospirillum rubrum ADP-ribose was identified as the modifying group (24), and NAD was demonstrated as the possible donor molecule (16).…”

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Regulation of nitrogenase activity by oxygen in Azospirillum brasilense and Azospirillum lipoferum

Hartmann¹,

Burris²

1987

J Bacteriol

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The nitrogenase activity of the microaerophilic bacteria Azospirillum brasiknse and A. lipoferum was completely inhibited by 2.0 kPa of oxygen (approximately 0.02 atm of 02) in equilibrium with the solution. The activity could be partially recovered at optimal oxygen concentrations of 0.2 kPa. In contrast to the NH4+ switch off, no covalent modification of the nitrogenase reductase (Fe protein) was involved, as demonstrated by Western-blotting and 32P-labeling experiments. However, the inhibition of the nitrogenase activity under anaerobic conditions was correlated with covalent modification of the Fe protein. In contrast to the NH4' switch off, no increase in the cellular glutamine pool and no modification of the glutamine synthetase occurred under anaerobic switch-off conditions. Therefore, a redox signal, independent of the nitrogen control of the cell, may trigger the covalent modification of the nitrogenase reductase of A. brasilense and A. lipoferum.The biological process of nitrogen fixation is tightly regulated. Besides the multiple regulation of nif gene expression by nitrogen compounds, oxygen, and temperature (25), the nitrogenase activity itself can be regulated precisely. In a variety of N2-fixing bacteria, the addition of ammonium chloride causes a rapid and reversible inhibition of nitrogenase activity (15,27,37). In some phototrophic bacteria (37) and in Azospirillum brasilense and A. lipoferum (8), a covalent modification of the nitrogenase reductase (Fe protein) causes a reversible inhibition of nitrogenase activity when low concentrations of ammonium chloride are added (NH4' switch off). In Rhodospirillum rubrum ADP-ribose was identified as the modifying group (24), and NAD was demonstrated as the possible donor molecule (16).A partially reversible oxygen switch off of nitrogenase activity was first reported for Azotobacter chroococcum (4) and has now been described for a number of N2-fixing bacteria (5,10,11,23,26,33). In Azotobacter spp., the reversible oxygen switch off has been correlated with the formation of an oxygen-insensitive, inactive complex of the nitrogenase with an Fe)S2 protein (28,30). Either the diversion of electrons towards respiration or the oxidation of electron donors (e.g., flavodoxin and hydroquinone) to nitrogenase at increased oxygen levels is an alternative explanation for the reversible inhibition of nitrogenase activity by oxygen (21,26,34,35).In the search for other possible mechanisms of nitrogenase regulation by oxygen, N2-fixing bacteria capable of inactivation by covalent modification of the Fe protein are interesting candidates. In previous studies with R. rubrum, the Fe protein was covalently modified when the cells were incubated at high oxygen concentrations (13). However, there was not a good correlation between the time courses for the loss of nitrogenase activity and for the modification process. A. brasilense and A. lipoferum, which possess the modification-inactivation system of the Fe protein of nitrogenase (8,17,22) MATERIALS AND METHODSOrganisms ...

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“…According to Zumft (1985), the activity of nitrogenase enzymes in diazotrophic bacteria are fast and reversibly inhibited when adding NH 4 + . However, this was not found when the bacteria were combined only with green manure.…”

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confidence: 99%

Green manure, seed inoculation with Herbaspirillum seropedicae and nitrogen fertilization on maize yield

Ávila

Ferreira

Santos

et al. 2020

Rev. bras. eng. agríc. ambient.

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The current need for increase crop yields requires the supplying of nutrients, mainly nitrogen, which increases the production cost, requiring the search for alternative products, such as seed inoculation with diazotrophic bacteria and green manures. In this context, the objective of this study was to evaluate the effect of green manure, seed inoculation with Herbaspirillum seropedicae, and nitrogen fertilization on the productive performance of maize crops. The experiment was conducted at the district of Estiva, in the municipality of Vitória da Conquista, BA, Brazil (14º 52’ 6’’ S, 40º 44’ 55’’ W, and altitude of 917 m), from December 2015 to August 2016. A randomized block design with four repetitions was used, in a 2 × 2 × 2 factorial arrangement, consisting of presence or absence of green manure (velvet bean), seed inoculation with Herbaspirillum seropedicae (strain ZAE94), and mineral nitrogen fertilization (120 kg ha-1). The maize ear length and diameter, number grains per row, ear weight without husks, cob weight, and grain yield were evaluated. A significant triple interaction was found for all evaluated variables. The use of green manure presented better results than the control. Velvet bean can be used as a green manure, as an alternative to soil mineral fertilization without yield losses.

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Regulation of Nitrogenase Activity in the Anoxygenic Phototrophic Bacteria

Cited by 12 publications

References 80 publications

Posttranslational regulatory system for nitrogenase activity in Azospirillum spp

Posttranslational regulatory system for nitrogenase activity in Azospirillum spp

Regulation of nitrogenase activity by oxygen in Azospirillum brasilense and Azospirillum lipoferum

Green manure, seed inoculation with Herbaspirillum seropedicae and nitrogen fertilization on maize yield

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