ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Immunological studies of ferredoxin-nitrite reductases and ferredoxin-glutamate synthases from photosynthetic organisms (1990)
    Springer
    Archives of microbiology 153 (1990), S. 230-234 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthetic organisms ; Chlamydomonas reinhardii ; Ferredoxin-glutamate synthase ; Ferredoxin-nitrite reductase ; Common antigenic determinants ; Ferredoxin-binding domain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polyclonal antiserum specific for ferredoxin-nitrite reductase (EC 1.7.7.1) from the green alga Chlamydomonas reinhardii recognized the nitrite reductase from other green algae, but did not cross-react with the corresponding enzyme from different cyanobacteria or higher plant leaves. An analogous situation was also found for ferredoxin-glutamate synthase (EC 1.4.7.1), using its specific antiserum. Besides, the antibodies raised against C. reinhardii ferredoxin-glutamate synthase were able to inactivate the ferredoxin-dependent activity of nitrite reductase from green algae. These results suggest that there exist similar domains in ferredoxin-nitrite reductases and ferredoxin-glutamate synthases from green algae. In addition, both types of enzymes share common antigenic determinants, probably located at the ferredoxin-binding domain. In spite of their physicochemical resemblances, no apparent antigenic correlation exists between the corresponding enzymes from green algae and those from higher plant leaves or cyanobacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249073
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Differential regulation of the nitrate-reducing and ammonium-assimilatory systems in synchronous cultures of Chlamydomonas reinhardtii (1991)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 78 (1991), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The enzymatic systems responsible for the reduction of nitrate and the assimilation of ammonium in the microalga Chlamydomonas reinhardtii showed markedly different evolution in synchronous cultures obtained by 12 h light/12 h dark transition. NAD(P)H-nitrate reductase and ferredoxin-nitrite reductase activities increased during the first 7–8 h of the light period, and then decreased, being almost negligible at the end of the dark period. By contrast, glutamine synthetase and both ferredoxin- and NADH-dependent glutamate synthase activities increased in the light and then remained at a constant and maximal value in the dark. Light seems to direct the synthesis of all N-assimilatory enzymes, with the exception of NADH-glutamate synthase, the activity of which increased only from the last 4 h of the light period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1991.tb04422.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Isolation of photorespiratory mutants from Lotus japonicus deficient in glutamine synthetase (2002)
    Oxford, UK : Blackwell Science, Ltd
    Physiologia plantarum 115 (2002), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A mutagenesis programme using ethyl methanesulphonate (EMS) was carried out on Lotus japonicus (Regel) Larsen cv. Gifu in order to isolate photorespiratory mutants in this model legume. These mutants were able to grow in a CO2-enriched atmosphere [0.7% (v/v) CO2] but showed stress symptoms when transferred to air. Among them, three mutants displayed low levels of glutamine synthetase (GS; EC 6.3.1.2) activity in leaves. The mutants accumulated ammonium in leaves upon transfer from 0.7% (v/v) CO2 to air. F1 plants of back crosses to wild type were viable in air and F2 populations segregated 3 : 1 (viable in air : air-sensitive) indicative of a single Mendelian recessive trait. Complementation tests showed that the three mutants obtained were allelic. Chromatography on DEAE-Sephacel used to separate the cytosolic and plastidic GS isoenzymes together with immunological data showed that: (1) mutants were specifically affected in the plastidic GS isoform, and (2) in L. japonicus the plastidic GS isoform eluted at lower ionic strength than the cytosolic isoform, contrary to what happens in most plants. The plastidic GS isoform present in roots of wild type L. japonicus was also absent in roots of the mutants, indicating that this plastidic isoform from roots was encoded by the same gene than the GS isoform expressed in leaf tissue. Viability of mutant plants in high-CO2 conditions indicates that plastidic GS is not essentially required for primary ammonium assimilation. Nevertheless, mutant plants did not grow as well as wild type plants in high-CO2 conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2002.1150304.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Characterisation and expression studies of a root cDNA encoding for ferredoxin-nitrite reductase from Lotus japonicus (2001)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 113 (2001), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A full-length cDNA encoding for ferredoxin-nitrite reductase (NiR, EC 1.7.7.1), has been isolated from a root cDNA library from the legume Lotus japonicus and characterised. The NiR gene (Nii) is present as a single copy in this plant, and encodes a protein of 582 amino acids. The Lotus NiR protein is synthesised as a precursor with an amino-terminal transit peptide consisting of 25 amino acid residues. Sequence comparisons with leaf NiRs from different plant species and with other related redox proteins identified in the root NiR the same highly conserved residues involved in the cofactor binding than previously reported for leaves. Besides, a putative binding site for ferredoxin was also found in the N-terminal region of the protein. The NiR gene is expressed in roots and leaves, although the level of expression is much higher in roots, in accordance with the fact that L. japonicus assimilates nitrate mainly in roots. NiR mRNA, protein and activity are induced by nitrate in roots and leaves, while ammonium-grown plants only showed basal levels. No oscillations of NiR mRNA, protein and activity were observed during the day/night cycle, neither in roots nor leaves, making an interesting difference with rhythms observed in other plant species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2001.1130206.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Regulation of the expression of ferredoxin-glutamate synthase in barley (1997)
    Springer
    Planta 203 (1997), S. 517-525 
    Details
    ISSN: 1432-2048
    Keywords: Key words: Glutamate synthase ; Hordeum (glutamate synthase) ; Light (N assimilation) ; Nitrogen assimilation ; Plant development ; Senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. We have investigated the regulation of ferredoxin–glutamate synthase (Fd-GOGAT) in leaves of barley (Hordeum vulgare L. cv. Maris Mink) at the mRNA, protein and enzyme activity levels. Studies of the changes in Fd-GOGAT during plant development showed that the activity in shoots increases rapidly after germination to reach a maximum (on a fresh-weight basis) at day 10 and then declines markedly to less than 50% of the maximal activity by day 30, this decline being correlated with an equivalent loss of Fd-GOGAT protein. Growing the plants in darkness reduced the maximum activity attained in the shoots, but did not affect the overall pattern of the changes or their timing. The activity of Fd-GOGAT increased two- to three-fold within 48 h when etiolated leaves were exposed to light, and Northern blots indicated that the induction occurred at the mRNA level. However, whilst a carbon source could at least partially substitute for light in the induction of nitrate reductase activity, no induction of Fd-GOGAT activity was seen when etiolated leaves were treated with either sucrose or glucose. Interestingly, the levels of Fd-GOGAT mRNA and activity remained high up to a period of 16 h or 72 h darkness, respectively. Compared with plants grown in N-free medium, light-grown plants supplied with nitrate had almost two-fold higher Fd-GOGAT activities and increased Fd-GOGAT mRNA levels, but nitrate had no effect on the abundance of the enzyme or its mRNA in etiolated plants, indicating that light is required for nitrate induction of barley Fd-GOGAT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004250050221
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Cloning and sequence analysis of a cDNA for barley ferredoxin-dependent glutamate synthase and molecular analysis of photorespiratory mutants deficient in the enzyme (1993)
    Springer
    Planta 189 (1993), S. 475-483 
    Details
    ISSN: 1432-2048
    Keywords: Amidotransferase ; Amino-terminal sequences ; Chromosomal assignment ; Glutamate synthase ; Hordeum (mutants) ; Photorespiration mutants (barley) ; Polymerase chain reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The NH2-terminal sequences of ferredoxin-dependent glutamate synthase (Fd-GOGAT; EC 1.4.7.1) purified from barley (Hordeum vulgare L.) and Chlamydomonas reinhardtii (Dangeard), and of a barley peptide, were determined and the barley sequences were used to design oligonucleotide primers for the polymerase chain reaction. A specific 1.3-kilobase (kb) cDNA fragment specifying the NH2-terminal one-third of the mature barley polypeptide, was amplified, cloned and sequenced. The NH2-terminus of plant Fd-GOGAT is highly conserved and homologous to the NH2-terminus of the heavy subunit of Escherichia coli NADPH-GOGAT. Based on sequence homologies, we tentatively identified the NH2-terminal region of Fd-GOGAT as the glutamine-amidotransferase domain, which is related to the corresponding domain of the purF-type amidotransferases. The Fd-GOGAT cDNA clone, and polyclonal antibodies raised against the barley enzyme, were used to analyse four Fd-GOGAT-deficient photorespiratory mutants. Three mutants (RPr 82/1, RPr 82/9 and RPr 84/82) had no detectable Fd-GOGAT protein in leaves, while the fourth (RPr 84/42) had a small amount of cross-reacting material. Hybridization to Northern blots of total leaf RNA revealed that both RPr 82/9 and RPr 84/82 were indistinguishable from the parental line (Maris Mink), having normal amounts of a 5.7-kb mRNA species. On the other hand, RPr 82/2 and RPr 84/42 each contained two distinct hybridizing RNA species, one of which was larger than 5.7 kb, the other smaller. Using a set of wheat-barley telosomic addition lines we have assigned the Fd-GOGAT structural locus to the short arm of chromosome 2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Purification and molecular properties of ferredoxin-glutamate synthase from Chlamydomonas reinhardii (1984)
    Springer
    Planta 162 (1984), S. 180-187 
    Details
    ISSN: 1432-2048
    Keywords: Chlamydomonas (ferredoxin-glutamate synthase) ; Ferredoxin-glutamate synthase ; Glutamate synthase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ferredoxin-glutamate synthase (EC 1.4.7.1) from Chlamydomonas reinhardii has been purified to electrophoretic homogeneity, with a specific activity of 10.4 units mg-1 protein, by a method which included chromatography on diethylaminoethyl sephacel and hydroxylapatite, and ferredoxin-sepharose affinity treatment. The enzyme is a single polypeptide chain of M r 146000 dalton which shows an absorption spectrum with maxima at 278, 377 and 437 nm, and an A276/A437 absorptivity ratio of 7.0. The anaerobic addition of dithionite results in the loss of the absorption peak at 437 nm, which is restored upon reoxidation of the enzyme with an excess of 2-oxoglutarate, alone or in the presence of glutamine. This indicates the presence in the enzyme of a flavin prosthetic group, which is functional during the catalysis. The ferredoxin-glutamate synthase can be assayed with methyl viologen, chemically reduced with dithionite, but it is unable to use reduced pyridine nucleotide. Azaserine, 6-diazo-5-oxo-norleucine, bromocresol green and p-hydroxymercuribenzoate are potent inhibitors of this activity, which, on the other hand, is stable upon heating at 45°C for 10 min.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410216
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Characterization of a light-dependent glutamate synthase activity in Chlamydomonas reinhardtii (1987)
    Springer
    Photosynthesis research 12 (1987), S. 73-81 
    Details
    ISSN: 1573-5079
    Keywords: Chlamydomonas ; photosynthesis ; biosynthesis of glutamate ; Fd-glutamate synthase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetically active vesicles prepared from Chlamydomonas reinhardtii retained a light-dependent glutamate synthase activity which was highly specific for 2-oxoglutarate (Km=2.1 mM) and L-glutamine (Km=0.9 mM) as amido group acceptor and donor respectively. This activity was inhibited by azaserine, p-hydroxymercuribenzoate and 3-(p-chlorophenyl)-1,1-dimethyl urea. Light-dependent synthesis of glutamate was also obtained by coupling Chlamydomonas photosynthetic particles to purified ferredoxin-glutamate synthase, using ascorbate and 2,6-dichlorophenol-indophenol as electron donor. This system was also specific for 2-oxoglutarate (Km=1 mM) and L-glutamine (Km=0.8 mM) as substrates, and was stimulated by dithioerythritol. Azaserine and p-hydroxymercuribenzoate, but not 3-(p-chlorophenyl)-1,1-dimethyl urea, inhibited the reconstituted activity; high concentrations of 2-oxoglutarate were inhibitory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019152
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Molecular analysis of barley mutants deficient in chloroplast glutamine synthetase (1990)
    Springer
    Plant molecular biology 14 (1990), S. 297-311 
    Details
    ISSN: 1573-5028
    Keywords: cDNA sequence ; chloroplast protein ; glutamine synthetase ; Hordeum vulgare L. ; mRNA ; mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A barley leaf cDNA library has been screened with two oligonucleotide probes designed to hybridize to conserved sequences in glutamine synthetase (GS) genes from higher plants. Two GS cDNA clones were identified as hybridizing strongly to one or both probes. The larger clone (pcHvGS6) contained a 1.6 kb insert which was shown by primer extension analysis to be an almost full-length cDNA. Both clones were more closely related to cDNAs for the chloroplast form of GS (GS2) from pea and Phaseolus vulgaris than to cDNAs for the cytosolic form (GS1). A sequence identicalto an N-terminal sequence determined from a purified preparation of the mature GS2 polypeptide (NH2-XLGPETTGVIQRMQQ) was found in the pcHvGS6-encoded polypeptide at residues 46–61, indicating a pre-sequence of at least 45 amino acids. The pre-sequence has only limited sequence homology to the pre-sequences of pea and P. vulgaris GS2 subunits, but is similarly rich in basic residues and possesses some of the structural features common to the targeting sequences of other chloroplast proteins. The molecular lesions responsible for the GS2-deficient phenotypes of eight photorespiratory mutants of barley were investigated using a gene-specific probe from pcHvGS6 to assay for GS2 mRNA, and an anti-GS antiserum to assay for GS2 protein. Three classes of mutants were identified: class I, in which absence of cross-reacting material was correlated with low or undetectable levels of GS2 mRNA; class II, which had normal or increased levels of GS2 mRNA but very little GS2 protein; and class III, which had significant amounts of GS2 protein but little or no GS2 activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028767
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Site-directed mutagenesis of Glu-297 from the α-polypeptide of Phaseolus vulgaris glutamine synthetase alters kinetic and structural properties and confers resistance to L-methionine sulfoximine (1999)
    Springer
    Plant molecular biology 40 (1999), S. 835-845 
    Details
    ISSN: 1573-5028
    Keywords: glutamine synthetase ; Phaseolus vulgaris ; plant nitrogen assimilation ; recombinant protein ; site-directed mutagenesis ; structure-function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this paper we examine the functionality of Glu-297 from the α-polypeptide of Phaseolus vulgaris glutamine synthetase (EC 6.3.1.2). For this purpose, the glnα cDNA was recombinantly expressed in Escherichia coli, and site-directed mutants constructed, in which this residue was replaced by alanine. The level of glutamine synthetase transferase catalytic activity in the mutant strain was 70-fold lower while biosynthetic activity remained practically unaffected. Kinetic parameters for both enzyme activities were not greatly altered except for the Km for ammonium in biosynthetic activity, which increased 100-fold. A similar result was reported when mutagenizing Glu-327 from E. coli glutamine synthetase, a residue shown to be present at the active site. This suggests that the Glu residue mutated in the higher-plant enzyme could develop a similar catalytic role to that of bacteria. Another characteristic feature of the mutant protein was its higher resistance to inhibition of the biosynthetic activity by L-methionine sulfoximine, a typical inhibitor of glutamine synthetase. In addition, we show that immunoreactivity of the glutamine synthetase mutant protein, both under native and denaturing conditions, is similar to the wild type, indicating that no deep conformational changes were produced as a consequence of the introduced mutation. However, structural changes in the active site can be predicted from alterations detected in the behaviour of the mutant protein towards affinity chromatography on 2′,5′-ADP-Sepharose, as compared to the wild type. Nevertheless, complementation of an E. coli glnA mutation indicated that the E297A mutant enzyme was physiologically functional.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006257323624
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...