Ammonia inhibition of nitrogenase activity in purple and green bacteria

Rodionov, Yu. V.; Лебедева, Н. В.; Kondratieva, E. N.

doi:10.1007/bf00412800

Cited by 14 publications

(6 citation statements)

References 6 publications

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“…There have been differences of opinion as to whether phototrophs grown on NH4+-limited medium are capable of NH4+ switch-off. Switch-off was reported under these conditions in R. rubrum (4,6,17,29,30), but others have not been able to reproduce this effect in either this organism or other phototrophs (1,2,5,10,21,23,24,25), with the exception of Rhodopseudomonas capsulata (2).…”

Section: Resultsmentioning

confidence: 93%

Changes in amino acid and nucleotide pools of Rhodospirillum rubrum during switch-off of nitrogenase activity initiated by NH4+ or darkness

Li¹,

Hu²,

Yoch³

1987

J Bacteriol

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Amino acid and nucleotide pools were measured in nitrogenase-containing Rhodospirillum rubrum cultures during NH4+-or dark-induced inactivation (switch-off) of the Fe protein. A big increase in the glutamine pool size preceded NH4+ switch-off of nitrogenase activity, but the glutamine pool rqmained unchanged during dark switch-off. Furthermore, methionine sulfoximine had no effect on the rate of dark switch-off, suggesting that glutamine plays no role in this process. In the absence of NH4' azaserine, an inhibitor of glutamate synthate, raised glutamine pool levels sufficiently to initiate switch-off in vivo. While added NH4L substantially increased the size of the nucleotide pools in N-limited cells, the kinetics of nucleotide synthesis were all similar and followed (rather than preceded) Fe protein inactivatioi. Darkness had little effect on nucleotide pool sizes. Glutamate pool sizes were also found to be important in NH4' switch-off because of the role of this molecule as a glutamine precursor. Much of the diversity reported in the observations on NH4' switch-off appears to be due to variations in glutamate pool sizes prior to the NH4+ shock. The nitrogen nutritional background is an important factor in determnining whether darkness initiates nitrogenase switch-off; however, no link has yet been established between this and NH4' (glutamine) switch-off.The nonsulfur photosynthetic bacteria are among a group of N2-fixing bacteria with nitrogenase activity that is subject to regulation by NH4'. Carithers et al. (4) and Nordlund and Eriksspn (17) showed that the inhibitory effect of NH4' on nitrogenase activity (switch-off) is related to the covalent modification and concurrent inactivation of the nitrogenase Fe protein extracted from glutamate-and N2-grown cells (13,14,18). Similar to the inactive Fe protein isolated from glutamate-grown cells, Fe protein extracted from NH4+-inhibited cells (4, 17) was inactive and could be reactivated by a membrane-bound activating enzyme (13, 18). Switch-off of nitrogenase activity by NH4' catalyzes the covalent modification of one of the two Fe protein subunits (6, 23) with one molecule of ADP-ribose (22).The role of NH4' as an in vivo signal to activate an Fe protein-inactivating enzyme has been the subject of numerous investigations. Glutamine mimics NH4' (16) and methionine sulfoximine (MSX), an inhibitor of glutamine synthetase (GS), prevents NH4' switch-off in Rhodospirillum rubrum (5,25,30) and all other N2 fixers that are capable of switch-off regulation (3, 9). 6-Diazo-5-oxo-L-norleucine (30) and azaserine (7) are inhibitors of glutamate synthase (GOGAT), and both initiate switch-off in the absence of NH4', presumably by blocking the normal flux of nitrogen through the GS-GOGAT pathway. This results in a glutamine buildup sufficient to initiate switch-off.The confirmed and extended to show that R. rubrum could rapidly reverse this process in the light (10). It is not readily apparent what glutamine and darkness have in common that leads to the activation of the Fe...

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Section: Resultsmentioning

confidence: 93%

Changes in amino acid and nucleotide pools of Rhodospirillum rubrum during switch-off of nitrogenase activity initiated by NH4+ or darkness

Li¹,

Hu²,

Yoch³

1987

J Bacteriol

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“…Switch-off of nitrogenase activity has been observed in purple and green sulphur bacteria [179][180][181] and also in some non-photosynthetic bacteria [182]. In Rb.…”

Section: Regulation Of Nitrogenase Activitymentioning

confidence: 98%

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Willison¹

1993

FEMS Microbiology Letters

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The biochemical genetics approach is defined as the use of mutants, in comparative studies with the wild‐type, to obtain information about biochemical and physiological processes in complex metabolic systems. This approach has been used extensively, for example in studies on the bioenergetics of the photosynthetic bacteria, but has been applied less frequently to studies of intermediary carbon and nitrogen metabolism in phototrophic organisms. Several important processes in photosynthetic bacteria—the regulation of nitrogenase synthesis and activity, the control of intracellular redox balance during photoheterotrophic growth, and chemotaxis—have been shown to involve metabolism. However, current understanding of carbon and nitrogen metabolism in these organisms is insufficient to allow a complete understanding of these phenomena. The purpose of the present review is to give an overview of carbon and nitrogen metabolism in the photosynthetic bacteria, with particular emphasis on work carried out with mutants, and to indicate areas in which the biochemical genetics approach could be applied successfully. In particular, it will be argued that, in the case of Rhodobacter capsulatus and Rb. sphaeroides, two species which are fast‐growing, possess a versatile metabolism, and have been extensively studied genetically, it should be possible to obtain a complete, integrated description of carbon and nitrogen metabolism, and to undertake a qualitative and quantitative analysis of the flow of carbon and reducing equivalents during photoheterotrophic growth. This would require a systematic biochemical genetic study employing techniques such as HPLC, NMR, and mass spectrometry, which are briefly discussed. The review is concerned mainly with Rb. capsulatus and Rb. sphaeroides, since most studies with mutants have been carried out with these organisms. However, where possible, a comparison is made with other species of purple non‐sulphur bacteria and with purple and green sulphur bacteria, and recent literature relevant to these organisms has been cited.

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“…The ferredoxin complex is the 228 carrier for this process, but the biomass needs energy in the form of ATP (Golomysova et al 229 2010). However, this process is inhibited in presence of NH 4 + , a strong inhibitor of the 230 nitrogenase activity (Rodionov et al 1986). Indeed, H 2 production is inhibited in a DWW fed 231 situation due to (i) presence of ammonium and (ii) disposing of electrons by CO 2 re-fixation 232 which promotes growth (see SI for more details).…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

A mechanistic model for anaerobic phototrophs in domestic wastewater applications: Photo-anaerobic model (PAnM)

et al. 2017

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Purple phototrophic bacteria (PPB) have been recently proposed as a key potential mechanism for accumulative biotechnologies for wastewater treatment with total nutrient recovery, low greenhouse gas emissions, and a neutral to positive energy balance. Purple phototrophic bacteria have a complex metabolism which can be regulated for process control and optimization. Since microbial processes governing PPB metabolism differ from traditional processes used for wastewater treatment (e.g., aerobic and anaerobic functional groups in ASM and ADM1), a model basis has to be developed to be used as a framework for further detailed modelling under specific situations. This work presents a mixed population phototrophic model for domestic wastewater treatment in anaerobic conditions. The model includes photoheterotrophy, which is divided into acetate consumption and other organics consumption, chemoheterotrophy (including simplified fermentation and anaerobic oxidation) and photoautotrophy (using hydrogen as an electron donor), as microbial processes, as well as hydrolysis and biomass decay as biochemical processes, and is single-biomass based. The main processes have been evaluated through targeted batch experiments, and the key kinetic and stoichiometric parameters have been determined. The process was assessed by analyzing a continuous reactor simulation scenario within a long-term wastewater treatment system in a photo-anaerobic membrane bioreactor.

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Ammonia inhibition of nitrogenase activity in purple and green bacteria

Cited by 14 publications

References 6 publications

Changes in amino acid and nucleotide pools of Rhodospirillum rubrum during switch-off of nitrogenase activity initiated by NH4+ or darkness

Changes in amino acid and nucleotide pools of Rhodospirillum rubrum during switch-off of nitrogenase activity initiated by NH4+ or darkness

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

A mechanistic model for anaerobic phototrophs in domestic wastewater applications: Photo-anaerobic model (PAnM)

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