1
|
Srivastava A, Singh SS, Mishra AK. Sodium transport and mechanism(s) of sodium tolerance inFrankiastrains. J Basic Microbiol 2012; 53:163-74. [DOI: 10.1002/jobm.201100586] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 02/16/2012] [Indexed: 11/06/2022]
Affiliation(s)
- Amrita Srivastava
- Laboratory of Microbial genetics, Department of Botany; Banaras Hindu University; Varanasi; India
| | - Satya Shila Singh
- Laboratory of Microbial genetics, Department of Botany; Banaras Hindu University; Varanasi; India
| | - Arun Kumar Mishra
- Laboratory of Microbial genetics, Department of Botany; Banaras Hindu University; Varanasi; India
| |
Collapse
|
2
|
Paz-Yepes J, Merino-Puerto V, Herrero A, Flores E. The amt gene cluster of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120. J Bacteriol 2008; 190:6534-9. [PMID: 18689479 PMCID: PMC2566009 DOI: 10.1128/jb.00613-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 07/30/2008] [Indexed: 11/20/2022] Open
Abstract
The genome of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 bears a gene cluster including three amt genes that, based on homology of their protein products, we designate amt4, amt1, and amtB. Expression of the three genes took place upon ammonium withdrawal in combined nitrogen-free medium and was NtcA dependent. The genes were transcribed independently, but an amt4-amt1 dicistronic transcript was also produced, and expression was highest for the amt1 gene. A mutant with the whole amt region removed could grow under laboratory conditions using ammonium, nitrate, or dinitrogen as the nitrogen source.
Collapse
Affiliation(s)
- Javier Paz-Yepes
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Américo Vespucio 49, E-41092 Seville, Spain.
| | | | | | | |
Collapse
|
3
|
Singh AK, Syiem MB, Singh RS, Adhikari S, Rai AN. A common transport system for methionine, L-methionine-DL-sulfoximine (MSX), and phosphinothricin (PPT) in the diazotrophic cyanobacterium Nostoc muscorum. Curr Microbiol 2008; 56:436-41. [PMID: 18266032 DOI: 10.1007/s00284-008-9111-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Accepted: 11/28/2007] [Indexed: 11/26/2022]
Abstract
We present evidence, for the first time, of the occurrence of a transport system common for amino acid methionine, and methionine/glutamate analogues L-methionine-DL-sulfoximine (MSX) and phosphinothricin (PPT) in cyanobacterium Nostoc muscorum. Methionine, which is toxic to cyanobacterium, enhanced its nitrogenase activity at lower concentrations. The cyanobacterium showed a biphasic pattern of methionine uptake activity that was competitively inhibited by the amino acids alanine, isoleucine, leucine, phenylalanine, proline, valine, glutamine, and asparagine. The methionine/glutamate analogue-resistant N. muscorum strains (MSX-R and PPT-R strains) also showed methionine-resistant phenotype accompanied by a drastic decrease in 35S methionine uptake activity. Treatment of protein extracts from these mutant strains with MSX and PPT reduced biosynthetic glutamine synthetase (GS) activity only in vitro and not in vivo. This finding implicated that MSX- and PPT-R phenotypes may have arisen due to a defect in their MSX and PPT transport activity. The simultaneous decrease in methionine uptake activity and in vitro sensitivity toward MSX and PPT of GS protein in MSX- and PPT-R strains indicated that methionine, MSX, and PPT have a common transport system that is shared by other amino acids as well in N. muscorum. Such information can become useful for isolation of methionine-producing cyanobacterial strains.
Collapse
Affiliation(s)
- Arvind Kumar Singh
- Department of Biochemistry, North-Eastern Hill University, Shillong, 793 022, India,
| | | | | | | | | |
Collapse
|
4
|
Khumanthem N, Syiem MB, Singh AK, Rai AN. Isolation and characterization of a Mastigocladus species capable of growth, N(2)-fixation and N-assimilation at elevated temperature. Indian J Microbiol 2007; 47:345-52. [PMID: 23100688 PMCID: PMC3450037 DOI: 10.1007/s12088-007-0062-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Revised: 09/07/2007] [Accepted: 09/08/2007] [Indexed: 10/22/2022] Open
Abstract
A Mastigocladus species was isolated from the hot spring of Jakrem (Meghalaya) India. Uptake and utilization of nitrate, nitrite, ammonium and amino acids (glutamine, asparagine, arginine, alanine) were studied in this cyanobacterium grown at different temperatures (25°C, 45°C). There was 2-3 fold increase in the heterocyst formation and nitrogenase activity in N-free medium at higher temperature (45°C). Growth and uptake and assimilation of various nitrogen sources were also 2-3 fold higher at 45°C indicating that it is a thermophile. The extent of induction and repression of nitrate uptake by NO(3) (-) and NH(4) (+), respectively, differed from that of nitrite. It appeared that Mastigocladus had two independent nitrate/nitrite transport systems. Nitrate reductase and nitrite reductase activitiy was not NO(3) (-)-inducible and ammonium or amino acids caused only partial repression. Presence of various amino acids in the media partially repressed glutamine synthetase activity. Ammonium (methylammonium) and amino acid uptake showed a biphasic pattern, was energy-dependent and the induction of uptake required de novo protein synthesis. Ammonium transport was substrate (NH(4) (+))-repressible, while the amino acid uptake was substrate inducible. When grown at 25°C, the cyanobacterium formed maximum akinetes that remained viable upto 5 years under dry conditions.
Collapse
Affiliation(s)
- Nonibala Khumanthem
- Department of Biochemistry, North Eastern Hill University, Shillong, India
- Mizoram University, Aizawl, 796009 Mizoram India
| | - Mayashree B. Syiem
- Department of Biochemistry, North Eastern Hill University, Shillong, India
- Mizoram University, Aizawl, 796009 Mizoram India
| | - Arvind K. Singh
- Department of Biochemistry, North Eastern Hill University, Shillong, India
- Mizoram University, Aizawl, 796009 Mizoram India
| | - Amar Nath Rai
- Department of Biochemistry, North Eastern Hill University, Shillong, India
- Mizoram University, Aizawl, 796009 Mizoram India
| |
Collapse
|
5
|
Paz-Yepes J, Herrero A, Flores E. The NtcA-regulated amtB gene is necessary for full methylammonium uptake activity in the cyanobacterium Synechococcus elongatus. J Bacteriol 2007; 189:7791-8. [PMID: 17704220 PMCID: PMC2168756 DOI: 10.1128/jb.00404-07] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Amt proteins constitute a ubiquitous family of transmembrane ammonia channels that permit the net uptake of ammonium by cells. In many organisms, there is more than one amt gene, and these genes are subjected to nitrogen control. The mature Amt protein is a homo- or heterooligomer of three Amt subunits. We previously characterized an amt1 gene in the unicellular cyanobacterium Synechococcus elongatus strain PCC 7942. In this work, we describe the presence in this organism of a second amt gene, amtB, which encodes a protein more similar to the bacterial AmtB proteins than to any other characterized cyanobacterial Amt protein. The expression of amtB took place in response to nitrogen step-down, required the NtcA transcription factor, and occurred parallel to the expression of amt1. However, the transcript levels of amtB measured after 2 h of nitrogen deprivation were about 100-fold lower than those of amt1. An S. elongatus amtB insertional mutant exhibited an activity for uptake of [14C]methylammonium that was about 55% of that observed in the wild type, but inactivation of amtB had no noticeable effect on the uptake of ammonium when it was supplied at a concentration of 100 microM or more. Because an S. elongatus amt1 mutant is essentially devoid of [14C]methylammonium uptake activity, the mature Amt transporter is functional in the absence of AmtB subunits but not in the absence of Amt1 subunits. However, the S. elongatus amtB mutant could not concentrate [14C]methylammonium within the cells to the same extent as the wild type. Therefore, AmtB is necessary for full methylammonium uptake activity in S. elongatus.
Collapse
Affiliation(s)
- Javier Paz-Yepes
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Spain
| | | | | |
Collapse
|
6
|
|
7
|
Muro-Pastor MI, Reyes JC, Florencio FJ. Ammonium assimilation in cyanobacteria. PHOTOSYNTHESIS RESEARCH 2005; 83:135-50. [PMID: 16143848 DOI: 10.1007/s11120-004-2082-7] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 07/17/2004] [Indexed: 05/04/2023]
Abstract
In cyanobacteria, after transport by specific permeases, ammonium is incorporated into carbon skeletons by the sequential action of glutamine synthetase (GS) and glutamate synthase (GOGAT). Two types of GS (GSI and GSIII) and two types of GOGAT (ferredoxin-GOGAT and NADH-GOGAT) have been characterized in cyanobacteria. The carbon skeleton substrate of the GS-GOGAT pathway is 2-oxoglutarate that is synthesized by the isocitrate dehydrogenase (IDH). In order to maintain the C-N balance and the amino acid pools homeostasis, ammonium assimilation is tightly regulated. The key regulatory point is the GS, which is controlled at transcriptional and posttranscriptional levels. The transcription factor NtcA plays a critical role regulating the expression of the GS and the IDH encoding genes. In the unicellular cyanobacterium Synechocystis sp. PCC 6803, NtcA controls also the expression of two small proteins (IF7 and IF17) that inhibit the activity of GS by direct protein-protein interaction. Cyanobacteria perceive nitrogen status by sensing the intracellular concentration of 2-oxoglutarate, a signaling metabolite that is able to modulate allosterically the function of NtcA, in vitro. In vivo, a functional dependence between NtcA and the signal transduction protein PII in controlling NtcA-dependent genes has been also shown.
Collapse
Affiliation(s)
- M Isabel Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Isla de la Cartuja, Universidad de Sevilla-CSIC, Av. Américo Vespucio s/n, Seville 41092, Spain. imuro@ ibvf.csic.es
| | | | | |
Collapse
|
8
|
Vázquez-Bermúdez MAF, Paz-Yepes J, Herrero A, Flores E. The NtcA-activated amt1 gene encodes a permease required for uptake of low concentrations of ammonium in the cyanobacterium Synechococcus sp. PCC 7942. MICROBIOLOGY (READING, ENGLAND) 2002; 148:861-869. [PMID: 11882722 DOI: 10.1099/00221287-148-3-861] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In the unicellular cyanobacterium Synechococcus sp. PCC 7942, ammonium/methylammonium transport activity has been characterized but ammonium transport genes have not been described. The amt1 gene encoding a permease responsible for high-affinity [14C]methylammonium transport in Synechococcus sp. PCC 7942 was cloned and inactivated. The Amt1 permease appeared essential to take up ammonium when it was present at low concentrations in the external medium and might also be involved in recapture of ammonium leaked out from the cells. Expression of amt1, which was induced in the absence of ammonium and also influenced by the inorganic carbon supply, was dependent on the NtcA transcriptional regulator. The promoter of amt1 was found to exhibit the structure of NtcA-activated promoters, and specific binding of purified NtcA to amt1 promoter sequences was observed. The results of this study indicate that amt1 belongs to the NtcA regulon and that NtcA may respond to both nitrogen and carbon availability.
Collapse
Affiliation(s)
- Marı A F Vázquez-Bermúdez
- Instituto de Bioquı́mica Vegetal y Fotosı́ntesis, CSIC-Universidad de Sevilla, Avda. Américo Vespucio s/n, E-41092 Sevilla, Spain1
| | - Javier Paz-Yepes
- Instituto de Bioquı́mica Vegetal y Fotosı́ntesis, CSIC-Universidad de Sevilla, Avda. Américo Vespucio s/n, E-41092 Sevilla, Spain1
| | - Antonia Herrero
- Instituto de Bioquı́mica Vegetal y Fotosı́ntesis, CSIC-Universidad de Sevilla, Avda. Américo Vespucio s/n, E-41092 Sevilla, Spain1
| | - Enrique Flores
- Instituto de Bioquı́mica Vegetal y Fotosı́ntesis, CSIC-Universidad de Sevilla, Avda. Américo Vespucio s/n, E-41092 Sevilla, Spain1
| |
Collapse
|
9
|
Singh D, Rai A, Singh H. Methylammonium (ammonium) uptake in a glutamine auxotroph of the cyanobacteriumAnabaena cycadeae. FEBS Lett 2001. [DOI: 10.1016/0014-5793(85)81337-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
10
|
Singh S, Bhattacharya J, Singh HN. Evidence for the involvement of a common genetic determinant in the control of thallium-resistant (Tl1-R) phenotype and salinity-tolerant phenotype in the cyanobacterium Nostoc muscorum. J GEN APPL MICROBIOL 2000; 46:225-229. [PMID: 12483581 DOI: 10.2323/jgam.46.225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Surendra Singh
- Department of Biological Sciences, Rani Durgavati University, Jabalpur-482 001 (M.P.), India
| | | | | |
Collapse
|
11
|
Shehawy RM, Kleiner D. Ammonium (methylammonium) transport by heterocysts and vegetative cells of Anabaena variabilis. FEMS Microbiol Lett 1999; 181:303-6. [PMID: 10585553 DOI: 10.1111/j.1574-6968.1999.tb08859.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Transport of the ammonium analogue [(14)C]methylammonium was similar in non-growing, fully differentiated heterocysts as compared to vegetative, multiplying cells of the filamentous cyanobacterium Anabaena variabilis. NH(4)(+) inhibited uptake into the cells and released accumulated methylammonium from the cells. These observations suggest that the main function of ammonium transport in heterocysts may not be NH(4)(+) acquisition but cyclic retention of ammonia produced by nitrogenase.
Collapse
Affiliation(s)
- R M Shehawy
- Mikrobiologie, Universität, D-95440, Bayreuth, Germany
| | | |
Collapse
|
12
|
Montesinos ML, Muro-Pastor AM, Herrero A, Flores E. Ammonium/methylammonium permeases of a Cyanobacterium. Identification and analysis of three nitrogen-regulated amt genes in synechocystis sp. PCC 6803. J Biol Chem 1998; 273:31463-70. [PMID: 9813059 DOI: 10.1074/jbc.273.47.31463] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ammonium is an important nitrogen source for many microorganisms and plants. Ammonium transporters whose activity can be probed with [14C]methylammonium have been described in several organisms including some cyanobacteria, and amt genes encoding ammonium/methylammonium permeases have been recently identified in yeast, Arabidopsis thaliana, and some bacteria. The unicellular cyanobacterium Synechocystis sp. PCC 6803 exhibited a [14C]methylammonium uptake activity that was inhibited by externally added ammonium. Three putative amt genes that are found in the recently published complete sequence of the chromosome of strain PCC 6803 were inactivated by insertion of antibiotic resistance-encoding gene-cassettes. The corresponding mutant strains were impaired in uptake of [14C]methylammonium. Open reading frame sll0108 (amt1) was responsible for a high affinity uptake activity (Ks for methylammonium, 2.7 microM), whereas open reading frames sll1017 (amt2) and sll0537 (amt3) made minor contributions to uptake at low substrate concentrations. Expression of the three amt genes was higher in nitrogen-starved cells than in cells incubated in the presence of a source of nitrogen (either ammonium or nitrate), but amt1 was expressed at higher levels than the other two amt genes. Transcription of amt1 was found to take place from a promoter bearing the structure of the cyanobacterial promoters activated by the nitrogen control transcription factor, NtcA.
Collapse
Affiliation(s)
- M L Montesinos
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, E-41092 Sevilla, Spain
| | | | | | | |
Collapse
|
13
|
Abstract
Cyanobacteria are N
2
-fixing oxygenic phototrophs with potential as sources of nitrogenous biofertilizer independent of fossil fuels. Recently, attention has been paid to their role in this respect, and to strain selection to facilitate enhanced agricultural productivity. The capacities to fix N
2
in the presence of combined nitrogen, to resist herbicides and to tolerate salinity changes and desiccation are of particular importance. Mutant strains of N
2
-fixing cyanobacteria with potential applications have been produced, including strains which photoproduce ammonia and amino acids, strains with altered transport systems and strains which are herbicide-resistant. By using bioreactors and immobilization systems in conjunction with these strains, techniques have been developed for extracellular product-liberation. Gene transfer systems are now available in both unicellular and filamentous cyanobacteria and these offer the possibility of strain selection and modification. The way in which these advances will contribute to the development of strains with desirable attributes for use in the field is discussed.
Collapse
|
14
|
Singh S, Negi S, Bharati N, Singh H. Common nitrogen control of caesium uptake, caesium toxicity and ammonium (methylammonium) uptake in the cyanobacterium Nostoc muscorum. FEMS Microbiol Lett 1994. [DOI: 10.1111/j.1574-6968.1994.tb06774.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
|
15
|
Srivastava R, Amla DV. Physiological and biochemical analysis of the glutamine synthetase-impaired mutants of the nitrogen-fixing cyanobacteriumNostoc muscorum. Curr Microbiol 1993. [DOI: 10.1007/bf01577378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
16
|
Singh S. Regulation of glutamate metabolism in the cyanobiontNostoc ANTH by nitrogen sources. J Basic Microbiol 1993. [DOI: 10.1002/jobm.3620330109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
17
|
|
18
|
Modi DR, Singh AK, Rao KS, Chakravarty D, singh HN. Construction of multiple herbicide resistant ammonia excreting strains of cyanobacteriumNostoc muscorum. Biotechnol Lett 1991. [DOI: 10.1007/bf01026761] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
19
|
Singh S. Urea metabolism in the cyanobacteriumAnabaena cycadeae: regulation of urea uptake and urease by ammonia. FEMS Microbiol Lett 1991. [DOI: 10.1111/j.1574-6968.1991.tb04593.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
20
|
|
21
|
Sing S, A.K. K, Singh N. Developmental regulation of methylammonium (ammonium) transport activity in the cyanobacterium Anabaena doliolum. FEMS Microbiol Lett 1990. [DOI: 10.1111/j.1574-6968.1990.tb04142.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
22
|
Vega-Palas MA, Madueño F, Herrero A, Flores E. Identification and cloning of a regulatory gene for nitrogen assimilation in the cyanobacterium Synechococcus sp. strain PCC 7942. J Bacteriol 1990; 172:643-7. [PMID: 1967601 PMCID: PMC208487 DOI: 10.1128/jb.172.2.643-647.1990] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Twenty-seven mutants that were unable to assimilate nitrate were isolated from Synechococcus sp. strain PCC 7942. In addition to mutants that lacked nitrate reductase or nitrite reductase, seven pleiotropic mutants impaired in both reductases, glutamine synthetase, and methylammonium transport were also isolated. One of the pleiotropic mutants was complemented by transformation with a cosmid gene bank from wild-type strain PCC 7942. Three complementing cosmids were isolated, and a 3.1-kilobase-pair DNA fragment that was still able to complement the mutant was identified. The regulatory gene that was cloned (ntcA) appeared to be required for full expression of proteins subject to ammonium repression in Synechococcus sp.
Collapse
Affiliation(s)
- M A Vega-Palas
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-Consejo Superior de Investigaciones Cientificas, Spain
| | | | | | | |
Collapse
|
23
|
Singh A, Sailaja M, Singh H. A class of glyphosate-selected mutants of the cyanobacteriumNostoc muscorumshowing loss of ammonium transport activity (Amtâ), heterocyst formation (Hetâ) and nitrogenase activity (Nifâ). FEMS Microbiol Lett 1989. [DOI: 10.1111/j.1574-6968.1989.tb03443.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
24
|
Reed RH. Osmotic adjustment and organic solute accumulation inChaetomorpha capillaris. ACTA ACUST UNITED AC 1989. [DOI: 10.1080/00071618900650021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
25
|
Franco AR, Cárdenas J, Fernández E. Regulation by ammonium of nitrate and nitrite assimilation in Chlamydomonas reinhardtii. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 951:98-103. [PMID: 3191135 DOI: 10.1016/0167-4781(88)90029-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The inhibitor of mRNA synthesis, 6-methylpurine, inhibited nitrate reductase derepression in either ammonium-grown or methylammonium-treated wild-type cells of Chlamydomonas reinhardtii, but not in nitrogen-starved cells. In contrast, 6-methylpurine did not inhibit nitrate reductase synthesis in the methylammonium-resistant mutant 2170 (ma-1) either grown on ammonium, treated with methylammonium or nitrogen starved, but did inhibit the continuous synthesis of nitrate reductase, which required the presence of nitrate in the media. In both wild-type and mutant 2170 grown on ammonium and transferred to nitrate media, cycloheximide immediately prevented nitrate reductase derepression when added either at the beginning or at different times of induction treatment. Unlike wild-type cells, mutant 2170 was able to take up either nitrate or nitrite simultaneously with ammonium in whose presence nitrate and nitrite reductases were synthesized. However, synthesis of nitrate reductase was progressively inhibited in the mutant cells when the intracellular ammonium levels were raised as a result of an increase in either the external pH or the extracellular ammonium concentrations. The results rule out the existence of maturase-like proteins in Chlamydomonas and indicate that ammonium has a double effect on the regulation of nitrate reductase synthesis: (a) it prevents nitrate reductase mRNA production; and (b) it controls negatively the expression of this mRNA.
Collapse
Affiliation(s)
- A R Franco
- Departamento de Bioquímica, Biología Molecular y Fisiología, Facultad de Ciencias, Universidad de Córdoba, Spain
| | | | | |
Collapse
|
26
|
|
27
|
Gibson J. [60] Ammonium transport. Methods Enzymol 1988. [DOI: 10.1016/0076-6879(88)67063-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
28
|
Boussiba S, Gibson J. Regulation of methylammonium/ammonium transport in the unicellular cyanobacterium Synechococcus R-2 (PCC 7942). FEMS Microbiol Lett 1987. [DOI: 10.1111/j.1574-6968.1987.tb02160.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
29
|
Involvement of Photosystem II in the ammonia metabolism of a heterotrophic cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1987. [DOI: 10.1016/0005-2728(87)90082-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
30
|
A mutant of Chlamydomonas reinhardtii altered in the transport of ammonium and methylammonium. ACTA ACUST UNITED AC 1987. [DOI: 10.1007/bf00428880] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
31
|
Jayakumar A, Hong JS, Barnes EM. Feedback inhibition of ammonium (methylammonium) ion transport in Escherichia coli by glutamine and glutamine analogs. J Bacteriol 1987; 169:553-7. [PMID: 3542962 PMCID: PMC211813 DOI: 10.1128/jb.169.2.553-557.1987] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
When cultured with glutamate or glutamine as the nitrogen source, Escherichia coli expresses a specific ammonium (methylammonium) transport system. Over 95% of the methylammonium transport activity in washed cells was blocked by incubation with 100 microM L-glutamine in the presence of chloramphenicol (100 micrograms/ml). The time course for the onset of this glutamine inhibition followed a first-order rate expression with a t1/2 of 2.8 min. The inhibition of transport by L-glutamine was noncompetitive (Ki = 18 microM) with respect to the [14C]methylammonium substrate. D-Glutamine had no significant effect. The glutamine analogs gamma-L-glutamyl hydroxamate (Ki = 360 microM) and gamma-L-glutamyl hydrazide (Ki = 800 microM) were also noncompetitive inhibitors of methylammonium transport, suggesting that glutamine metabolism is not required. The role of the intracellular glutamine pool in the regulation of ammonium transport was investigated by using mutants carrying defects in the operon of glnP, the gene for the glutamine transporter. The glnP mutants had normal rates of methylammonium transport but were refractory to glutamine inhibition. Glycylglycine, a noncompetitive inhibitor of methylammonium uptake in wild-type cells (Ki = 43 microM), was equipotent in blocking transport in glnP mutants. Although ammonium transport is also subject to repression by growth of E. coli in the presence of ammonia, this phenomenon is unrelated to glutamine inhibition. A GlnL RegC mutant which constitutively expressed ammonium transport activity exhibited a sensitivity to glutamine inhibition similar to that of wild-type cells. These findings indicate that ammonium transport in E. coli is regulated by the internal glutamine pool via feedback inhibition.
Collapse
|
32
|
Nitrite uptake and its regulation in the cyanobacterium Anacystis nidulans. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 1987. [DOI: 10.1016/0005-2736(87)90361-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
33
|
Rai AN, Lindblad P, Bergman B. Absence of the glutamine-synthetase-linked methylammonium (ammonium)-transport system in the cyanobiont of Cycas-cyanobacterial symbiosis. PLANTA 1986; 169:379-381. [PMID: 24232650 DOI: 10.1007/bf00392134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/1986] [Accepted: 05/23/1986] [Indexed: 06/02/2023]
Abstract
Using the ammonium analogue (14)CH3NH 3 (+) , ammonium transport was studied in the cyanobiont cells freshly isolated from the root nodules of Cycas revoluta. An L-methionine-DL-sulphoximine (MSX)-insensitive ammonium-transport system, which was dependent on membrane potential (ΔΨ), was found in the cyanobiont. However, the cyanobiont was incapable of metabolizing exogenous (14)CH3NH 3 (+) or NH 4 (+) because of the absence of another ammonium-transport system responsible for the uptake of ammonium for assimilation via glutamine synthetase (EC 6.3.1.2). Such a modification seems to be the result of symbiosis because the free-living cultured isolate, Anabaena cycadeae, has been shown to possess both the ammonium-transport systems.
Collapse
Affiliation(s)
- A N Rai
- Department of Biochemistry, North-Eastern Hill University, 793 014, Shillong, India
| | | | | |
Collapse
|
34
|
Singh D, Modi D, Singh H. Evidence for glutamine synthetase and methylammonium (ammonium) transport system as two distinct primary targets of methionine sulfoximine inhibitory action in the cyanobacteriumAnabaena doliolum. FEMS Microbiol Lett 1986. [DOI: 10.1111/j.1574-6968.1986.tb01773.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
35
|
Reich S, Almon H, Böger P. Short-term effect of ammonia on nitrogenase activity ofAnabaena variabilis(ATCC29413). FEMS Microbiol Lett 1986. [DOI: 10.1111/j.1574-6968.1986.tb01347.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
36
|
Reed RH, Warr SR, Kerby NW, Stewart WD. Osmotic shock-induced release of low molecular weight metabolites from free-living and immobilized cyanobacteria. Enzyme Microb Technol 1986. [DOI: 10.1016/0141-0229(86)90080-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
37
|
Mackerras AH, Smith GD. Evidence for direct repression of nitrogenase by ammonia in the cyanobacterium Anabaena cylindrica. Biochem Biophys Res Commun 1986; 134:835-44. [PMID: 3080996 DOI: 10.1016/s0006-291x(86)80496-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The nitrogenase activity of the cyanobacterium Anabaena cylindrica was repressed upon addition of ammonium salts after preincubation in the presence of a concentration of L-methionine-DL-sulfoximine sufficient to totally inhibit glutamine synthetase. Repression was also observed when urea was added to cells in the presence of the glutamine synthetase inhibitor. Measurements of ammonia concentrations were made in each case and provided evidence that ammonia itself is a primary regulator of nitrogenase levels in A. cylindrica.
Collapse
|
38
|
|
39
|
Holtel A, Kleiner D. Regulation of methylammonium transport inParacoccus denitrificans. Arch Microbiol 1985. [DOI: 10.1007/bf00693405] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
40
|
Liberation of ammonia during nitrogen fixation by a facultatively heterotrophic cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1985. [DOI: 10.1016/0005-2728(85)90165-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
41
|
|
42
|
|
43
|
|
44
|
Physiological and Biochemical Aspects of N2-Fixing Cyanobacteria. ACTA ACUST UNITED AC 1985. [DOI: 10.1007/978-94-009-5175-4_53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
45
|
Abstract
We describe an NH4+-specific transport system in the N2-fixing symbiotic actinomycete Frankia sp. strain CpI1. [14C]methylammonium was used as an NH4+ analog. No specific transport process was detected when cells were grown on high concentrations of NH4+. A transport system with a high affinity for CH3NH3+ was synthesized after 3 to 4 h of nitrogen starvation. Methylammonium transport was not significantly inhibited by a variety of amino acids, primary amines, and polyamines. Ammonium completely eliminated CH3NH3+ transport. The Km for CH3NH3+ transport was around 2 +/- 1.8 microM with a Vmax of 4 to 5 nmol/min per mg of protein. The electron transport inhibitors cyanide and azide eliminated uptake, as did the uncoupler carbonyl cyanide-m-chlorophenylhydrazone. The sulfydryl reagent p-chloromercuribenzoic acid and the heavy metal thallium also inhibited uptake, suggesting the presence of an NH4+-specific permease. Concentration of CH3NH3+ across the membrane was demonstrated by conducting uptakes at low temperature to slow the metabolism of CH3NH3+ by glutamine synthetase. At 7 degrees C most of the label was concentrated inside the cells in a form that could be chased from the cells by adding excess NH4+ to the medium. At 30 degrees C most of the label was present as an impermeant metabolite. Thin-layer chromatography of cell extracts confirmed that the radioactivity inside the cells was mainly in the form of CH3NH3+ at 7 degrees C but was present as an unidentified metabolite at 30 degrees C. These studies demonstrate that Frankia sp. strain CpI1 has a high-affinity NH4+ transport system that is synthesized in response to NH4+ starvation.
Collapse
|
46
|
Kashyap AK, Johar G. Genetic control of ammonium transport in nitrogen fixing cyanobacterium Nostoc muscorum. ACTA ACUST UNITED AC 1984. [DOI: 10.1007/bf00329951] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|