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  • Analytical Chemistry and Spectroscopy  (7)
  • Lignin model compounds  (5)
  • Chemical Engineering  (4)
  • 1
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; β-Aryl ether dimers ; Metabolism ; Methoxyhydroquinone ; Alkyl-phenyl cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized guaiacylglycol-β-guaiacyl ether (I) in high nitrogen, shaking and stationary cultures. 2-(o-Methoxyphenoxy) ethanol (X), 2-(o-methoxyphenoxy) acetic acid (IX) and methoxy-phydroquinone (MHQ) were identified as products of the metabolism of (I). P. chrysosporium also metabolized guaiacylglycerol-β-guaiacyl ether (IV) in high nitrogen stationary cultures. 2-(o-Methoxyphenoxy)-1,3 propanediol (XII) and 3-hydroxy, 2-(o-methoxy-phenyxy) propionic acid (XIV) were identified as products of the metabolism of (IV). Finally, P. chrysosporium metabolized α-deoxyguaiacylglycol-β-guaiacyl ether (VI) and α-deoxyguaiacylglycerol-β-guaiacyl ether (VII) in limiting nitrogen cultures. 2-(o-Methoxyphenoxy) ethanol (X) and 2-(o-methoxyphenoxy)-1,3 propanediol (XII) were identified as products of the metabolism of VI and VII respectively indicating α hydroxylation of those substrates with subsequent alkyl-phenyl bond cleavage. Metabolites were identified after comparison with chemically synthesized standards by GLC-mass spectrometry.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; Lignin metabolism ; β-aryl ether dimers ; β-ether cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized 4-ethoxy-3-methoxyphenyl-glycerol-β-guaiacyl ether (V) in low nitrogen, stationary cultures under which conditions the ligninolytic enzyme system is expressed. 4-Ethoxy-3-methoxyphenylglycerol XIII, guaicol and 4-ethoxy-3-methoxybenzyl alcohol (II) were isolated as metabolic products. Exogenously added XIII was rapidly converted to 4-ethoxy-3-methoxybenzyl alcohol indicating that it is an intermediate in the metabolism of V. P. chrysosporium also metabolized 1-(4′-ethoxy-3′-methoxyphenyl)-2-(2″-methoxyphenoxy)-3-hydroxypropane VI. The degradation pathway for this dimer also included initial β-ether cleavage and α-hydroxylation of the diol product 1-(4′-ethoxy-3′-methoxyphenyl) 2,3 dihydroxypropane (XI) to yield the triol XIII which was cleaved at the α, β bond to yield 4-ethoxy-3-methoxybenzyl alcohol. Finally P. chrysosporium also cleaved the dimer 1-(4′-ethoxy-3′-methoxyphenyl)-2-(2″-methoxyphenoxy)-1-hydroxypropane (VIII) at the β-ether linkage yielding 1-(4′-ethoxy-3′-methoxyphenyl) 1,2 dihydroxypropane (IX) which was subsequently cleaved at the α, β bond to yield II. All of the results indicate that oxidative β-ether cleavage is an important initial reaction in the metabolism of β-aryl ether lignin substructure dimeric compounds. Metabolities were identified after comparison with chemically synthesized standards by gas liquid chromatography-mass spectrometry.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Vicinal diol cleavage ; Lignin model compounds ; Dihydroanisoin ; Anlsyl alcohol ; White rot basidiomycete ; Anisaldehyde ; Cytochrome P-450 ; Activated oxygen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized dihydroanisoin (1,2-dianisylethane-1,2 diol) in low nitrogen stationary cultures, conditions under which the ligninolytic system is expressed. Anisyl alcohol was isolated as a metabolic product indicating an initial diol bond cleavage of the substrate. Use of 3H-labeled dihydroanisoin (1,2-dianisylethane-1,2-diol-1,2 3H) indicated that the diol bond was cleaved directly, yielding anisyl aldehyde as the initial product. The metabolically stable ketol anisoin was shown not be an intermediate in the metabolism of dihydroanisoin. The diol cleavage reaction was dependent on the concentration of molecular oxygen but O2 could be replaced by H2O2 under some conditions. The cleavage reaction was inhibited by exogenously-added tyrosine2-Cu2+ complex (TCC). The appearance of the fungal diol cleavage system parallels the appearance of the ligninolytic system under a variety of physiological conditions. In addition, preincubation of ligninolytic cultures with 2.5 mM l-glutamate represses both the ligninolytic and the diol cleavage activities.
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  • 4
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; β-aryl ether dimers ; Metabolism αβ cleavage ; Veratryl alcohol ; 4-ethoxy-3-methoxybenzyl alcohol ; Alkyl-phenyl cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot fungus Phanerochaete chrysosporium metabolized the lignin model compounds veratylglycerol-β-guaiacyl ether I and 4-ethoxy-3-methoxy-phenylglycerol-β-guaiacyl ether V in stationary culture under an atmosphere of 100% oxygen and under nitrogen limiting conditions. 2-(o-methoxyphenoxy)-ethanol VII was identified as a product of the metabolism of both substrates. Veratryl alcohol and 4-ethoxy-3-methoxybenzyl alcohol IV were identified as metabolites of I and V respectively. Metabolites were identified after comparison with chemically synthesized standards by mass spectrometry. These results indicate the existence of an enzyme system capable of directly cleaving the etherated dimers I and V at the α, β bond. The additional identification of 2-(o-methoxyphenoxy)-1,3 propanediol IX as a metabolic product indicates that cleavage of the alkyl-phenyl bond of these dimers or their metabolites also occurs.
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  • 5
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; Lignin degradation ; Diarylpropane ; α,β cleavage ; Anisyl alcohol ; Lignin ; Basidiomycete
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized 1-(3′,4′-diethoxyphenyl)-1,3(dihydroxy)-2-(4′'-methoxyphenyl)-propane (XII) in low nitrogen stationary cultures, conditions under which the ligninolytic enzyme system is expressed. 3,4-Diethoxybenzyl alcohol (IV), 1,2(dihydroxy)-1-(4′-methoxyphenyl)ethane (XX) and anisyl alcohol were isolated as metabolic products indicating an initial α, β bond cleavage of this dimer. Exogenously added XX was rapidly converted to anisyl alcohol, indicating that XX is an intermediate in the metabolism of XII. Fungal cleavage of the α, β bond of 1-(3′-4′-diethoxyphenyl)-1-(hydroxy)-2-(4′'-methoxyphenyl)ethane (XI) also occurred, indicating that a γ hydroxymethyl group is not a prerequisite for this reaction. P. chrysosporium also metabolized 1-(4′-ethoxy-3′-methoxyphenyl)-2,2(dihydroxy)-2-(4′'-methoxyphenyl)propane-1-ol (XIII). The major products of the degradation of this triol included 4-ethoxy-3-methoxybenzyl alcohol (III) and 2-hydroxy-1-(4′-methoxyphenyl)-1-oxoethane (XXI). The nature of the products formed indicates that this triol is also cleaved directly at the α,β bond. The significant difference in the nature of the products formed from the diaryl propane (XII) and the triol (XIII), however, suggests that XIII is not an intermediate in the major pathway for the degradation of XII. Metabolites were identified after comparison with chemically synthesized standards by GLC-mass spectrometry.
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  • 6
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The application of reductive coulometric electrochemical detection for analysis of the monoamine neurotransmitters norepinephrine, dopamine, and serotonin and their common metabolites in brain and cerebrospinal fluid following separation by isocratic high performance liquid chromatography is described. The high sensitivity and screening capabilities of coulometric electrodes permits the accurate quantitation of as little as 3-5 pg of these compounds in tissue following a simple single step purification procedure. Moreover, comparison of peak height ratios obtained from analysis of authentic reference standards and tissue samples at selected multiple electrode potentials provides a straightforward means for qualitative evaluation of peak identification and purity during analysis of biological samples. The method is comparatively inexpensive and precise within and between day coefficients of variation for most compounds range from 2-5%. Thirty samples can be run in duplicate in a 24 h period.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 38 (1992), S. 1593-1608 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A huge amount of data is collected by computer monitoring systems in the chemical process industry. Such tools as principal component analysis and partial least squares have been shown to be very effective in compressing this large volume of noisy correlated data into a subspace of much lower dimension than the original data set. Because most of what is eliminated is the collinearity of the original variables and the noise, the bulk of the information contained in the original data set is retained. The resulting low dimensional representation of the data set has been shown to be of great utility for process analysis and monitoring, as well as in selecting variables for control. These types of models can also be used directly in control system design. One way of approaching this is to use the loading matrices as compensators on the plant. Some advantages of using this approach as part of the overall control system design include automatic decoupling and efficient loop pairing, as well as natural handling of nonsquare systems and poorly conditioned systems.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1988), S. 211-213 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of octafluorotoluene (OFT) as a versatile gas chromatographic/mass spectrometric derivatizing agent for steroids containing alcoholic, phenolic or α,β-unsaturated keto functions, is described. Two distinct derivatizing schemes can be utilized, involving (method 1) a phase-transfer reaction, employing a two-phase system of CH2Cl2 and N NaOH with n-Bu4NHSO4 as catalyst (suitable for alcoholic and phenolic steroids) and (method 2) a reaction conducted in anhydrous dimethylformamide at 155°C with CsF as base (appropriate for α,β-unsaturated keto steroids). Perfluorotolyl (PFT) ethers and/or enol ethers have thus been generated. The electron impact spectra display abundant high-mass molecular ions where derivatization has occurred at a phenolic or enolic function. An extraction, derivatization and gas chromatographic/mass spectrometric scheme has been devised involving method 2 for the analysis of steroids in human plasma. A preliminary quantitative investigation of the levels of testosterone in plasma has been carried out employing these methods. The anomalously high level found is explained in terms of the presence in plasma of lipid-soluble derivatives of testosterone (probably fatty acid esters) which generate the testosterone bis-OFT derivative under the reaction conditions employed.
    Additional Material: 2 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 8 (1981), S. 503-505 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three physiologically important disaturated lecithins have been analyzed quantitatively as the acetate derivatives using a solids inlet probe and ammonia chemical ionization. Concentration independent response factors have been determined over a tenfold range that brackets human plasma levels. The results obtained serve as an independent corroboration of gas chromatographic analyses.
    Additional Material: 1 Ill.
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  • 10
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectra of mercapturic acid conjugates of two xenobiotic products of lipid peroxidation (trans-4-hydroxy-2-hexenal and trans-4-hydroxy-2-nonenal) as well as conjugates of 1,3-dichloropropene, styrene oxide, 1,2-naphthalene oxide and α-chlorotoluene were obtained using fast atom bombardment or negative chemical ionization. Fragmentation pathways were investigated using linked scan and mass-analyzed ion kinetic energy spectrometric techniques. Characteristics of the spectra obtained using different ionization and sample introduction techniques are compared. Deprotonated molecular ions of mercapturic acids gave simple daughter ion spectra, with the dominant mode of decomposition involving cleavage of C—S bonds giving a characteristic neutral loss of 129 Da Screening for mercapturates in urine samples was performed using neutral loss scanning and yielded limits of detection in the low nanogram per milliliter range. Quantitative analysis of the S-benzyl mercapturic acid at 1 p.p.b. in urine has been demonstrated using combined gas chromatography/electron capture mass spectrometry with d3-S-benzyl mercapturic acid as internal standard.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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