Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • crystal structure  (3)
  • Crystal structure  (2)
  • Cyanobacteria  (2)
  • sediment  (2)
  • 1
    Digitale Medien
    Digitale Medien
    Cloning and expression of a Nostoc sp. leucine biosynthetic gene in Escherichia coli (1986)
    Springer
    Archives of microbiology 145 (1986), S. 315-321 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Cyanobacteria ; DNA restriction and cloning ; Gene fusions ; Leucine biosynthesis ; Mutant complementation ; Nostoc ; Transcription
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Genomic DNA extracted from the symbiotically-competent, heterocyst-forming cyanobacterium Nostoc sp. strain 7801 was resistant to cleavage by a number of restriction endonucleases. A cosmid library of Nostoc DNA was prepared and maintained in the modification-limited Escherichia coli strain HB101. Analysis of cloned Nostoc DNA fragments indicated infrequent occurrence of restriction endonuclease recognition sites in the Nostoc genome. The Nostoc genomic library was screened for sequences complementing mutations in the E. coli leucine and proline biosynthetic operons. Two cosmids complementing leuB were isolated but none for leuA, leuC, leuD, or proA were detected in 1000 cosmids. A 3.0 kb fragment subcloned from one of the cosmids complemented mutations in leuB when inserted into the HindIII site of pBR322 in either orientation, demonstrating that transcription of leuB originated within the cloned fragment. The cloned fragment also carries a second site capable of initiating transcription of fused antibiotic resistance genes. While transcription of Nostoc DNA sequences did occur in E. coli, unknown barriers must also exist that prevented additional biological complementation of specific E. coli mutations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00470864
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Crystal structure and spectroscopy of the low-spin iron(II) compound: tris(bipyrimidine)iron(II) bis(triflate), [Fe(bipym)33](CF3SO3)2 (2000)
    Springer
    Journal of chemical crystallography 30 (2000), S. 441-444 
    Details
    ISSN: 1572-8854
    Schlagwort(e): 2,2′-Bipyrimidine ; low-spin ; iron ; crystal structure ; infrared
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The compound [Fe(bipym)33](CF3SO3)2 (in which bipym = 2,2′-bipyrimidine) crystallizes in the space group P21/c, with a = 13.7641(11), b = 18.7557(19), c = 12.3627(11) Å, β = 103.085(8)° and Z = 4. The low-spin Fe(II) atom is octahedrally surrounded by six nitrogen atoms of three bipyrimidine groups with Fe—N distances that vary from 1.968(4) to 1.975(4) å. In the far-infrared region the Fe—N vibrations are observed at 359 and 372 cm-1.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1011339214337
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Synthesis, spectroscopy, and X-ray structure of the polymer catena-[bis(azido-N)-copper(II)-μ-bis(2-benzimidazolyl)butane] (2000)
    Springer
    Journal of chemical crystallography 30 (2000), S. 69-72 
    Details
    ISSN: 1572-8854
    Schlagwort(e): azido ; crystal structure ; copper(II) ; infrared ; polymeric
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The title compound, catena-[bis(azido-N)-copper(II)-μ(bis(2-benzimidazolyl)butane), [Cu(C18H18N4)(N3)2]n, was obtained from the reaction of the ligand bis(2-benzimidazolyl)butane and Cu(N3)2. The x-ray crystal structure is reported. The compound crystallizes in the monoclinic space group P21/c with a = 8.2524(10), b = 12.765(5), c = 9.1125(15) Å, β = 106.423(12)°, Z = 2. The Cu(II) ions are square-planar coordinated with trans-oriented end-on binding azido ligands. The structure is a polynuclear chain with the benzimidazole bridging at each end. In addition a N(ligand)-H···N(azido) H-bridge [N(ligand)···N(azido) = 2.994(7) Å] is present, resulting in a pseudo 2-dimensional lattice. The characteristic azido infrared vibrations are found at 2060 and 2077 cm−1 (νas(N3)) and 1284 and 1297 cm−1 (ν(N3)).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009506418398
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Redox processes in recent sediments of the river Meuse, The Netherlands (2000)
    Springer
    Biogeochemistry 48 (2000), S. 217-235 
    Details
    ISSN: 1573-515X
    Schlagwort(e): diagenesis ; modelling ; organic matter ; pore water ; redox ; sediment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract Pore-water concentrations of inorganic solutes were measured at four locations in a recent sedimentation area of the river Meuse in The Netherlands. The pore-water concentration profiles were interpreted using the steady state one-dimensional reaction/transport model STEADYSED1. This model explicitly accounts for the organic matter degradation pathways and secondary redox reactions. Results show that the model reproduces the measured pore-water profiles of redox species reasonably well, although significant divergence is observed for pH. The latter is due to the absence of pH buffering by CaCO3 in the model. At all locations, methanogenesis is the major pathway of organic matter degradation below 3 cm from the sediment-water interface. However, organic matter degradation rates by methanogenesis may be overestimated, because methane ebullition is not included. Differences in profiles of redox-sensitive ions among the four locations are explained by differences in depositional conditions, in particular the sediment accumulation rate and supply of organic matter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006268325889
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Crystal structure and spectroscopy of bis-[bis(2-benzimidazolyl)propane]copper(II) bis(triflate)monohydrate, a copper complex with a geometry intermediate between tetrahedral and square planar (2000)
    Springer
    Journal of chemical crystallography 30 (2000), S. 793-797 
    Details
    ISSN: 1572-8854
    Schlagwort(e): copper ; bis(benzimidazoles) ; crystal structure ; infrared
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The structure of a mononuclear copper(II) compound with the ligand bis(2-benzimidazolyl)propane (abbreviated as tbz) is reported. The compound [Cu(tbz)2](CF3SO3)2(H2O) crystallizes in the triclinic space group P $$\bar 1$$ , with a = 12.363(6), b = 13.218(9), c = 15.365(8) Å, α = 82.74(5), β = 68.04(4), γ = 65.30(5), and Z = 2. The Cu(II) atom has a geometry intermediate between tetrahedral and square planar, consisting of four nitrogen atoms of two tbz ligands. The Cu—N—Cu angles are about 135°, while the dihedral angle between them amounts to 62° (0° for square planar and 90° for a tetrahedron). Ligand field bands are observed at 10.2 × 103, 13.8 × 103, and 20.3 × 103 cm−1, while the most characteristic infrared vibrations of the triflate anion are observed at 1273, 1260, 1238, 1221, 1171, and 1157 cm−1.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1013276325343
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Mobilisation of Heavy Metals in Contaminated Sediments in the River Meuse, The Netherlands (1999)
    Springer
    Water, air & soil pollution 116 (1999), S. 567-586 
    Details
    ISSN: 1573-2932
    Schlagwort(e): Complexation ; diffusion ; heavymetals ; mobilisation ; sediment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Due to seasonal variation in bottom-water temperature and degradation of organic matter, the depths of the redox boundaries fluctuate in sediments of the river Meuse. This is reflected by a non-steady state behaviour of heavy metals in the surface sediments. Levels of acid-volatile sulphides suggest that dissolved concentrations of heavy metals in the anoxic pore waters are determined by their respective sulphide phases. However, complexation with dissolved organic ligands may significantly increase dissolved concentrations of heavy metals. In most sediments studied, a distinct peak in dissolved concentrations of heavy metals is measured immediately below the sediment-water interface. This concentration peak may be attributed to degradation of organic matter and oxidation of sulphides. Dissolved concentration gradients indicate that upward diffusion of heavy metals from the sediment can contribute to concentrations in the surface water, although significant effects may be confined to specific locations. In addition, it is shown that release of heavy metals as dissolved species to the surface water is negligible compared to particulate-bound fluxes of heavy metals to the sediment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005146927718
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Isolation and characterization of Anacystis nidulans R2 mutants affected in nitrate assimilation: Establishment of two new mutant types (1988)
    Springer
    Molecular genetics and genomics 213 (1988), S. 223-228 
    Details
    ISSN: 1617-4623
    Schlagwort(e): Cyanobacteria ; Nitrate reductase mutants ; Nitrite reductase mutants ; Regulatory mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Eighteen mutant strains of the unicellular cyanobacterium Anacystis nidulans R2 that are unable to assimilate nitrate have been isolated after transposon Tn901 mutagenesis. Characterization of phenotypes and transformation tests have allowed the distinction of five different mutant types. The mutants exhibiting a nitrate reductase-less phenotype were identified as being affected in previously defined loci, as they could be transformed to the wild type by one of the plasmids pNR12, pNR63 or pNR193, which contain cloned genes of A. nidulans R2 involved in nitrate reduction. The mutations in strains FM2 and FM16 appear to affect two other genes involved in nitrate assimilation. Strain FM2 apparently bears a single mutation which results in both lack of nitrite reductase activity and loss of ammonium-promoted repression of nitrate reductase synthesis. FM16 has a low but significant level of nitrate reductase that is also freed from repression by ammonium, and an increased level of nitrite reductase activity. FM16 exhibited properties which indicate that this mutant strain might also be affected in the transport of nitrate into the cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00339585
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    A Unique Copper-Controlled Template Synthesis of Tetradentate N4-Donor Ligands and Their Propeller-Type Linear Trinuclear CuII Complexes (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 547-549 
    Details
    ISSN: 1434-1948
    Schlagwort(e): Copper ; Trinuclear ; Formamidines ; Magnetism ; Crystal structure ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In situ reaction of CuII triflate with aminopyridine or aminopyrimidine and triethylorthoformate in ethanol results in unique linear trinuclear CuII complexes with the general formula [Cu3(L-)4](CF3SO3)2(EtOH)x (L = dehydronated ligand N,N′-bis(pyridine-2-yl)formamidine or the new ligand N,N′-bis(pyrimidine-2-yl)formamidine). The structure [Cu-Cu-Cu angle 175.19(2)°] consists of four nearly flat molecules of the ligand which contribute to the propeller-type structure around the Cu-Cu-Cu axis. A strong antiferromagnetic interaction between the CuII ions is observed, resulting in an S = 1/2 ground state below 100 K.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
  • 9
    Digitale Medien
    Digitale Medien
    An Unprecedented, Copper-Mediated, In-Situ Multi-Step Ligand Formation - Synthesis, Structure, and Magnetism of Bis(μ-methoxo)bis[nitrato(2-methoxy- methylamino-3-methylpyridine)copper(II)] (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1577-1579 
    Details
    ISSN: 1434-1948
    Schlagwort(e): Copper ; Methoxo-bridged complexes ; Crystal structure ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A novel chelating ligand, synthesized in situ within the coordination sphere of CuII from 2-amino-3-methylpyridine, MeOH, and dioxygen from the air, is found to form a strongly coupled, dinuclear methoxo-bridged CuII compound with the formula [Cu(L)(CH3O)(NO3)]2 (L = 2-methoxymethylamino-3-methylpyridine). The geometry around the copper atom is square pyramidal and the Cu-Cu distance within the dinuclear unit is 3.011(2) Å with an Cu-O-Cu angle of 103.13(8)°. Synthesis, X-ray crystal structure, and magnetism are reported.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...