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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 152 (1989), S. 515-519 
    ISSN: 1432-072X
    Keywords: Diphenylether ; Degradation pathway ; Phenol ; 2-Pyrone-6-carboxylic acid ; Ether cleavage ; Pseudomonas cepacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The microbial degradation of hard coal implies the cleavage of diaryl ether linkages in the coal macromolecule. We investigated the biodegradation of diphenylether as a model compound representing this substructure of coal. A bacterial strain isolated from soil and identified as Pseudomonas cepacia, was able to grow with diphenylether as sole source of carbon. During microbial growth, three metabolites were detected in the culture supernatant by high pressure liquid chromatography. As product of ring hydroxylation and subsequent rearomatization, 2,3-dihydroxydiphenylether was identified by UV, mass and nuclear magnetic resonance spectrometry and gas chromatography analyses. The cleavage of the ether linkage led to the formation of phenol and 2-pyrone-6-carboxylic acid, the latter being not further degraded by Pseudomonas cepacia. The possible cleavage mechanism of the ether linkage is discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 153 (1990), S. 324-328 
    ISSN: 1432-072X
    Keywords: Dibenzothiophene ; Desulfurization ; Mineralization ; Degradation pathway ; Brevibacterium sp.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dibenzothiophene, a polycyclic aromatic sulfur heterocycle, represents as a model compound the organic sulfur integrated in the macromolecular coal matrix. A pure culture of a Brevibacterium species was isolated, which is able to use dibenzothiophene as sole source of carbon, sulfur and energy for growth. During dibenzothiophene utilization sulfite was released in a stoichiometrical amount and was further oxidized to sulfate. Three metabolites of dibenzothiophene degradation were isolated and identified as dibenzothiophene-5-oxide, dibenzothiophene-5-dioxide and benzoate by cochromatography, UV spectroscopy and gas chromatographymass spectrometry analyses. Based on the identified metabolites a pathway for the degradation of dibenzothiophene by Brevibacterium sp. DO is proposed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-072X
    Keywords: Diphenylether degradation ; Arylether linkage ; 2,3-Dihydroxybiphenyl dioxygenase ; 2-Pyrone-6-carboxylic acid ; Pseudomonas cepacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 2,3-Dihydroxybiphenyl dioxygenase from Pseudomonas cepacia Et 4 was found to catalyze the ring fission of 2,3-dihydroxydiphenylether in the course of diphenylether degradation. The enzyme was purified and characterized. It had a molecular mass of 240 kDa and is dissociated by SDS into eight subunits of equal mass (31 kDa). The purified enzyme was found to be most active with 2,3-dihydroxybiphenyl as substrate and showed moderate activity with 2,3-dihydroxydiphenylether, catechol and some 3-substituted catechols. The K m-value of 1 μM for 2,3-dihydroxydiphenylether indicated a high affinity of the enzyme towards this substrate. The cleavage of 2,3-dihydroxydiphenylether by 2,3-dihydroxybiphenyl dioxygenase lead to the formation of phenol and 2-pyrone-6-carboxylate as products of ring fission and ether cleavage without participation of free intermediates. Isotope labeling experiments carried out with 18O2 and H2 18O indicated the incorporation of 18O from the atmosphere into the carboxyl residue as well as into the carbonyl oxygen of the lactone moiety of 2-pyrone-6-carboxylate. Based on these experimental findings the reaction mechanism for the formation of phenol and 2-pyrone-6-carboxylate is proposed in accordance with the mechanism suggested by Kersten et al. (1982).
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The gene designated pepR1, encoding a potential transcription regulator of Lactobacillus delbrueckii subsp. lactis DSM7290, was identified by sequence similarity of an open reading frame located upstream of the prolidase pepQ orientated in opposite direction. pepQ and pepR1 coding regions are spaced by 152 nucleotides. Upstream of the -35 region of pepQ, a 14-bp palindromic sequence, homologous to the catabolite responsive element, could be identified. The pepR1 gene has the potential to encode a protein of 333 amino acids with a calculated molecular mass of 36955 Da and a calculated p/ of 5.5. The deduced protein sequence shows significant identity to the catabolite control protein of Bacillus. Co-expression in Escherichia coli was studied with the pepR1-pepQ intergenic region fused to the promoterless β-galactosidase reporter gene. The pepQ-β-galactosidase hybrid displayed an enhanced expression in the presence of cloned pepR1.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 107 (1993), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract A gene product with an apparent molecular mass of approximately 39000 Da can be identified in the cytoplasmic membrane of Escherichia coli upon expression of cloned envC. In this communication we report that the product was labelled with [3H]glycerol and [3H]palmitic acid, and a precursor molecule of increased molecular mass was accumulated when cells were treated with globomycin, a specific inhibitor for the prolipoprotein signal peptidase. The same precursor molecule was encoded by an envC mutant gene, in which the cysteine residue in a pentapeptide sequence, Leu-Ile-Ala-Gly-Cys24 within the amino terminal region of EnvC, was replaced by tryptophane (Trp24). This protein was not labelled with [3H]glycerol. The results demonstrate that the envC gene product represents a new lipoprotein of the cytoplasmic membrane of E. coli.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In this communication we report the first successful transformation of Lactobacillus delbrückii ssp. lactis WS97 with plasmid DNA by means of electroporation and describe the optimization of the transformation procedure for this strain. Efficiencies of electroporation varied between 102 to 104 transformants per μg pGK12, depending on the strain from which the DNA was isolated. The application of electroporation in molecular cloning was achieved by using the newly constructed origin screening vector, pAZ8. The replication origins of two cryptic plasmids were cloned. These plasmids were isolated from a thermophilic Lactobacillus strain Lb. delbrückii ssp. lactis WS97 and a mesophilic Lactobacillus strain Lb. casei NCDO151 which are both used in the dairy industry as starter cultures.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 122 (1994), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The transcriptional start points of ten Lactobacillus delbrückii ssp. lactis DSM7290 genes were determined by primer extension. The upstream located promoter regions, including potential −35 and −10 regions and the spacing between them were compared to the well-known Escherichia coli and Bacillus subtilis promoters. The Lb. delbrückii−35 consensus sequence (TTGACA) seems to be less conserved then the E. coli sequence. The nucleotides TGC were often found upstream of the −10 region (TATAAT). The most frequently observed spacing between the two core promoter regions was 17 nt and the main distance between the −10 region and the transcriptional start point was mostly determined to be 6 nt in contrast to 7 nt, as described for E. coli promoters. The preferred initiation nucleotides in Lb. delbrückii were shown to be definitely purines (A or G). The ribosome binding sites located downstream of the promoters revealed the consensus sequence 3′-UCCUCCU-5′, being the predicted 3′-OH end of the Lactobacillus 16S rRNA with a high degree of homology to known 16S rRNAs.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 124 (1994), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract A genomic library of Lactobacillus delbrueckii ssp. lactis DSM7290 in the low copy number vector pLG339, was screened for the presence of peptidase genes. Using the chromogenic substrate gly-ala-β-naphthylamide, which is not a substrate for any of the recently cloned peptidases of DSM7290, and the multiple peptidase deficient Escherichia coli strain CM89, allowed the isolation of clones, which contained the equivalent hydrolytic activity. To identify genes encoding the conserved catalytic active site of cysteine proteases, partial nucleotide sequencing with a degenerate oligonucleotide was performed on recombinant plasmids isolated from such clones. This allowed to identify two out of nine clones to carry the Lactobacillus pepC gene. A total of 2026 nucleotides were determined, and sequence analysis revealed a gene with strong homology to the recently cloned Lb. helveticus (73.2%) and Lactococcus lactis (51.03%) pepC genes, and the derived protein showed homology with the active site of a large number of cysteine proteases. The predicted open reading frame consists of 449 codons, coding for a protein of 50 909 Da. The enzyme is functional and extremely overexpressed in E. coli.
    Type of Medium: Electronic Resource
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  • 9
    facet.materialart.
    Unknown
    Köln : Periodicals Archive Online (PAO)
    Zeitschrift für Religions- und Geistesgeschichte. 32 (1980) 152 
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  • 10
    facet.materialart.
    Unknown
    Köln : Periodicals Archive Online (PAO)
    Zeitschrift für Religions- und Geistesgeschichte. 34 (1982) 28 
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