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
Filter
  • Articles  (190)
Collection
Source
Keywords
Publisher
Years
Journal
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Metabolism of acrylonitrile by Klebsiella pneumoniae (1991)
    Springer
    Archives of microbiology 156 (1991), S. 231-238 
    Details
    ISSN: 1432-072X
    Keywords: Nitriles ; Biodegradation ; Klebsiella pneumoniae ; Acrylonitrile metabolites ; Nitrile hydratase ; Amidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A gram-negative rod-shaped bacterium capable of utilizing acrylonitrile as the sole source of nitrogen was isolated from industrial sewage and identified as Klebsiella pneumoniae. The isolate was capable of utilizing aliphatic nitriles containing 1 to 5 carbon atoms or benzonitrile as the sole source of nitrogen and either acetamide or propionamide as the sole source of both carbon and nitrogen. Gas chromatographic and mass spectral analyses of culture filtrates indicated that K. pneumoniae was capable of hydrolyzing 6.15 mmol of acrylonitrile to 5.15 mmol of acrylamide within 24 h. The acrylamide was hydrolyzed to 1.0 mmol of acrylic acid within 72 h. Another metabolite of acrylonitrile metabolism was ammonia, which reached a maximum concentration of 3.69 mM within 48 h. Nitrile hydratase and amidase, the two hydrolytic enzymes responsible for the sequential metabolism of nitrile compounds, were induced by acrylonitrile. The optimum temperature for nitrile hydratase activity was 55°C and that for amidase was 40°C; both enzymes had pH optima of 8.0.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249120
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Mechanism of metronidazole-resistance by isolates of nitroreductase-producing Enterococcus gallinarum and Enterococcus casseliflavus from the human intestinal tract (2003)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 225 (2003), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Enterococcus casseliflavus and Enterococcus gallinarum strains resistant to metronidazole, nitrofurantoin and nitrofurazone were isolated from fecal samples of a patient with recurrent ulcerative colitis treated with metronidazole. Unlike other metronidazole-resistant bacteria, these strains produced nitroreductase but metabolized metronidazole to compounds that could not be detected by liquid chromatography with UV or mass spectral analysis. Metronidazole-susceptible Clostridium perfringens grew equally well in spent cultures of Enterococcus spp. incubated with or without metronidazole. These data indicate that the nitroreductases produced by these Enterococcus strains did not activate metronidazole to bactericidal metabolites and these bacteria may reduce the effectiveness of metronidazole. We have indirect evidence for an alternative pathway that results in metronidazole resistance. These strains of enterococcus had nitroreductase so resistance should not have occurred.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0378-1097(03)00513-5
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of nitropolycyclic aromatic hydrocarbons with the substituent at the longest axis (1992)
    s.l. : American Chemical Society
    The @journal of organic chemistry 57 (1992), S. 3746-3748 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00039a049
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Transformation of cinoxacin by Beauveria bassiana (2002)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 214 (2002), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The ability of the fungus Beauveria bassiana ATCC 7159 to transform the antibacterial agent cinoxacin was investigated. Cultures in sucrose–peptone broth were dosed with cinoxacin, grown for 20 days, and then extracted with ethyl acetate. Two metabolites were detected and purified by high-performance liquid chromatography. The major metabolite was identified by mass and proton nuclear magnetic resonance spectra as 1-ethyl-1,4-dihydro-3-(hydroxymethyl)[1,3]dioxolo[4,5-g]cinnolin-4-one and the minor metabolite was identified as 1-ethyl-1,4-dihydro-6,7-dihydroxy-3-(hydroxymethyl)cinnolin-4-one. B. bassiana also reduced quinoline-3-carboxylic acid to 3-(hydroxymethyl)quinoline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.2002.tb11336.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Evidence for the role of 2-hydroxychromene-2-carboxylate isomerase in the degradation of anthracene by Sphingomonas yanoikuyae B1 (1997)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 153 (1997), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Sphingomonas yanoikuyae B1 is extremely versatile in its catabolic ability. An insertional mutant strain, S. yanoikuyae EK504, which is unable to grow on naphthalene due to the loss of 2-hydroxychromene-2-carboxylate isomerase activity, was utilized to investigate the role of this enzyme in the degradation of anthracene by S. yanoikuyae B1. Although EK504 is unable to grow on anthracene, this strain could transform anthracene to some extent. A metabolite in the degradation of anthracene by EK504 was isolated by high-pressure liquid chromatography (HPLC) and was identified as 6,7-benzocoumarin by UV-visible, gas-chromatographic, HPLC/mass-spectrometric, and 1H nuclear magnetic resonance spectral techniques. The identification of 6,7-benzocoumarin provides direct chemical and genetic evidence for the involvement of nahD in the degradation of anthracene by S. yanoikuyae B1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1997.tb12613.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Carboxymethylation of cellulose in unconventional media (1999)
    Springer
    Cellulose 6 (1999), S. 153-165 
    Details
    ISSN: 1572-882X
    Keywords: cellulose functionalisation ; carboxymethyl cellulose ; cellulose solvents ; homogeneous procedure ; reactive microstructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Carboxymethylation of cellulose in the new and highly efficient aqueous solvent Ni(tren)(OH)2, [tren=tris(2‐aminoethyl)amine] and in melts of LiClO4· 3H2O or N‐methyl‐morpholine‐N‐oxide (NMMNO), which is now widely applied for cellulose fibre production, was investigated. In case of Ni(tren)(OH)2, a totally homogeneous carboxymethylation of cellulose with sodium monochloroacetate, in the presence of an aqueous NaOH solution is possible for the first time. Structure analysis by means of HPLC and 1 H‐NMR after chain degradation showed results comparable with findings for CMC obtained by the heterogeneous slurry process, that is, a statistic distribution of substituents along the polymer chain and functionalisation of the hydroxyl groups in the order C‐6 ≥ C‐2 〉 C‐3. The etherification of cellulose in a melt of LiClO4· 3H2O, a new type of cellulose solvent, was shown to be possible and gave products of a statistic functionalisation pattern as well. In contrast, carboxymethylation starting from solutions of cellulose in NMMNO initiated with solid NaOH particles yields polymers with a nonstatistic distribution of functional groups along the chain, as observed for cellulose ethers prepared in reactive microstrctures starting from solutions of cellulose intermediates in dimethyl sulfoxide as well as of unmodified cellulose dissolved in N,N‐dimethyl acetamide/LiCl.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009271427760
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Characterisation of regioselectively functionalized 2,3-O-carboxymethyl cellulose by enzymatic and chemical methods (2000)
    Springer
    Cellulose 7 (2000), S. 161-175 
    Details
    ISSN: 1572-882X
    Keywords: 2,3-O-carboxymethyl cellulose ; molar mass distribution ; endoglucanase hydrolysis ; anion exchange chromatography ; distribution of functional groups
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The determination of the molecular structure of 2,3-O-carboxymethyl cellulose (2,3-O-CMC), prepared via 6-O-(4-monomethoxy)triphenylmethyl cellulose, was carried out in detail by means of enzymatic and chemical methods. The 2,3-O-CMCs had degrees of substitution (DS) in the range of 0.5–1.2 showing a narrow molar mass distribution as revealed by SEC. As a result of an endoglucanase treatment, an intensive depolymerization of the samples occurred which was more pronounced for 2,3-O-CMC with comparatively low DS. All degraded samples could be separated into 18 fractions by preparative SEC and the proportion of each individual repeat unit was analysed by anion exchange chromatography (AEC) following complete hydrolytic chain degradation. The results indicated a homogeneous distribution of the functional groups within the polymer chain. Moreover, it became obvious that a preferred carboxymethylation of O-2 compared with O-3 occurred and that a preferred functionalization of already carboxymethylated units occurred as the reaction progressed. AEC with pulsed amperometric detection, which was used to separate and analyse the differently functionalized repeating units as well as glucose, had to be calibrated. Therefore, a method to determine the response factors of the individual carboxymethylated glucose units was developed using 13C NMR spectroscopic measurements (inverse gated decoupling) of depolymerised 2,3-O-CMC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009249224441
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Permeation and separation characteristics for benzene/cyclohexane mixtures through tosylcellulose membranes in pervaporation (1999)
    Springer
    Cellulose 6 (1999), S. 221-231 
    Details
    ISSN: 1572-882X
    Keywords: benzene/cyclohexane mixture ; benzene‐permselectivity ; degree of tosylation ; mechanism of separation ; tosylcellulose membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Tosylcelluloses (TosCells) with different degrees of tosylation were synthesized as membrane materials for the separation of benzene/cyclohexane (Bz/Chx) mixtures. TosCell membranes showed a high benzene‐permselectivity for the Bz/Chx mixtures in pervaporation (PV). An increase in the benzene concentration in the feed mixtures increased permeation rate but decreased the benzene‐permselectivity of the TosCell membranes. The increase in the permeation rate was attributed to the increase of the degree of swelling of the TosCell membranes by the feed mixtures and the decrease in the benzene‐permselectivity was mainly caused by the decrease of sorption selectivity. With low benzene concentrations in the Bz/Chx mixtures, the permeation rate of a TosCell membrane with a higher degree of tosylation was greater than that with a lower degree of tosylation, but was vice versa with a high benzene concentration. The benzene‐permselectivity of the former TosCell membrane was higher than that of the latter membrane. Differences of the permeation rate and benzene‐permselectivity with changes in the benzene concentration in the feed mixture and degree of tosylation of the TosCell membrane were significantly influenced by the degree of swelling of the TosCell membrane and the benzene concentration sorbed into the TosCell membrane. Mechanism of separation for the Bz/Chx mixtures through the TosCell membranes is discussed by the solution–diffusion model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009296930025
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    AC corona-discharge aerosol-neutralization device adapted to liquid chromatography/particle beam/mass spectrometry (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 138-142 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An AC corona-discharge device was inserted upstream of a thermospray vaporizer tip in a liquid chromatography/particle beam mass spectrometer to neutralize static aerosol charging. Response of a test analyte was measured with or without discharge initiation. If the solvent contained no ammonium acetate buffer, increased analyte signal was associated with the discharge. However, in the presence of ammonium acetate the benefit of AC discharge neutralization was either not observed or was more subtle. This led to the conclusion that the previously observed ammonium acetate “carrier” effect is attributable, at least in part, to neutralization of static electric charges produced spontaneously during the solvent nebulization process. In a second experiment, the pattern of particles issuing from the system momentum separator was examined by aiming the particle beam at a cold target located within a mass spectrometer ion source. Variations in particle density were observed depending on (i) whether or not the aerosol had been neutralized and (ii) the proximity of electron-beam-collimating magnets to the particle beam trajectory. These results are consistent with a hypothesis that electrostatic charging occurs spontaneously during the nebulization process in which an aerosol is formed from the high performance liquid chromatography effluent. Such electrostatic charging introduces a factor likely to degrade system performance by at least two modes: through interactions of the charged aerosol particles (i) with the walls of the aerosol transmission pathway, and, after they are accelerated into a particle beam and introduced into the mass spectrometer, (ii) with the magnets used for electron beam collimation in many mass spectrometer ion sources.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290090207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Sphärische ionotrope gele carboxygruppenhaltiger cellulosederivate als trägermaterialien für biologische wirkstoffe, I. Struktur- und quellungsuntersuchungen an xerogelen aus carboxymethylcellulose und aluminiumionen (1989)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 169 (1989), S. 69-82 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Insoluble spherical xerogel particles of aluminium carboxymethyl cellulose are prepared by partial drying of ionotropic gels formed by dropping aqueous solutions of sodium carboxymethyl cellulose into crosslinking solutions of aluminium salts. The swelling ability of the porous and mechanically stable carriers, which are surrounded by a dense surface, rises by partial transformation of carboxy groups into the sodium salts and diminishes with growing content of free acid groups and increasing temperature of drying.
    Notes: Unlösliche sphärische Aluminiumcarboxymethylcellulose-Xerogelpartikel werden durch partielle Trocknung ionotroper Gele hergestellt, die durch Eintropfen wäßriger Lösungen von Natriumcarboxymethylcellulose in vernetzende Aluminiumsalzlösungen entstehen. Das Quellvermögen der porösen und mechanisch stabilen Trägermaterialien, die von einer dichten Außenschicht umgeben sind, erhöht sich durch partielle Umwandlung von Carboxygruppen in die Natriumsalze; es verringert sich mit zunehmendem Gehalt an freien Säuregruppen und steigender Trocknungstemperatur.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1989.051690107
    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...