scholarly journals Regio- and stereo-selective metabolism of 4-methylbenz[a]anthracene by the fungus Cunninghamella elegans

1983 ◽  
Vol 216 (2) ◽  
pp. 377-384 ◽  
Author(s):  
C E Cerniglia ◽  
P P Fu ◽  
S K Yang
Keyword(s):  
Epoxide Hydrolase ◽  
Microsomal Fraction ◽  
Reversed Phase ◽  
Cunninghamella Elegans ◽  
Visible Absorption ◽  
Spectral Techniques ◽  
Methyl Group ◽  
Mass Spectral ◽  
C Elegans ◽  
Enzyme Systems

Metabolism of 4-methylbenz[a]anthracene by the fungus Cunninghamella elegans was studied. C. elegans metabolized 4-methylbenz[a]anthracene primarily at the methyl group, this being followed by further metabolism at the 8,9- and 10,11-positions to form trans-8,9-dihydro-8,9-dihydroxy-4-hydroxymethylbenz[a]anthracene and trans-10,11-dihydro-10,11-dihydroxy-4-hydroxymethylbenz[a]anthracene. There was no detectable trans-dihydrodiol formed at the methyl-substituted double bond (3,4-positions) or at the ‘K’ region (5,6-positions). The metabolites were isolated by reversed-phase high-pressure liquid chromatography and characterized by the application of u.v.-visible-absorption-, 1H-n.m.r.- and mass-spectral techniques. The 4-hydroxymethylbenz[a]anthracene trans-8,9- and −10,11-dihydrodiols were optically active. Comparison of the c.d. spectra of the trans-dihydrodiols formed from 4-methylbenz[a]anthracene by C. elegans with those of the corresponding benz[a]anthracene trans-dihydrodiols formed by rat liver microsomal fraction indicated that the major enantiomers of the 4-hydroxymethylbenz[a]anthracene trans-8,9-dihydrodiol and trans- 10,11-dihydrodiol formed by C. elegans have S,S absolute stereochemistries, which are opposite to those of the predominantly 8R,9R- and 10R,11R-dihydrodiols formed by the microsomal fraction. Incubation of C. elegans with 4-methylbenz[a]anthracene under 18O2 and subsequent mass-spectral analysis of the metabolites indicated that hydroxylation of the methyl group and the formation of trans-dihydrodiols are catalysed by cytochrome P-450 mono-oxygenase and epoxide hydrolase enzyme systems. The results indicate that the fungal mono-oxygenase-epoxide hydrolase enzyme systems are highly stereo- and regio-selective in the metabolism of 4-methylbenz[a]anthracene.

scholarly journals Fungal Biotransformation of 6-Nitrochrysene

1998 ◽  
Vol 64 (8) ◽  
pp. 3106-3109 ◽  
Author(s):  
Jairaj V. Pothuluri ◽  
John B. Sutherland ◽  
James P. Freeman ◽  
Carl E. Cerniglia
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Magnetic Resonance ◽  
High Performance ◽  
Environmental Contaminant ◽  
Cunninghamella Elegans ◽  
Spectral Techniques ◽  
Mass Spectral ◽  
Uv Visible

ABSTRACT The fungus Cunninghamella elegans was used to biotransform 6-nitrochrysene, a mutagen that is a widespread environmental contaminant. After 6 days, 74% of the3H-labeled 6-nitrochrysene added had been metabolized to two isomeric sulfate conjugates. These conjugates were separated by high-performance liquid chromatography and identified by UV-visible, 1H nuclear magnetic resonance, and mass spectral techniques as 6-nitrochrysene 1-sulfate and 6-nitrochrysene 2-sulfate.

scholarly journals Biodegradation of Chloroxylenol by Cunninghamella elegans IM 1785/21GP and Trametes versicolor IM 373: Insight into Ecotoxicity and Metabolic Pathways

2021 ◽  
Vol 22 (9) ◽  
pp. 4360
Author(s):  
Marta Nowak ◽  
Katarzyna Zawadzka ◽  
Janusz Szemraj ◽  
Aleksandra Góralczyk-Bińkowska ◽  
Katarzyna Lisowska
Keyword(s):  
Trametes Versicolor ◽  
Significant Rise ◽  
Pcr Analysis ◽  
Cunninghamella Elegans ◽  
Oxidation Reactions ◽  
Cytochrome P450 Enzymes ◽  
C Elegans ◽  
Real Time Quantitative Pcr ◽  
Genes Expression ◽  
By Products

Chloroxylenol (PCMX) is applied as a preservative and disinfectant in personal care products, currently recommended for use to inactivate the SARS-CoV-2 virus. Its intensive application leads to the release of PCMX into the environment, which can have a harmful impact on aquatic and soil biotas. The aim of this study was to assess the mechanism of chloroxylenol biodegradation by the fungal strains Cunninghamella elegans IM 1785/21GP and Trametes versicolor IM 373, and investigate the ecotoxicity of emerging by-products. The residues of PCMX and formed metabolites were analysed using GC-MS. The elimination of PCMX in the cultures of tested microorganisms was above 70%. Five fungal by-products were detected for the first time. Identified intermediates were performed by dechlorination, hydroxylation, and oxidation reactions catalysed by cytochrome P450 enzymes and laccase. A real-time quantitative PCR analysis confirmed an increase in CYP450 genes expression in C. elegans cells. In the case of T. versicolor, spectrophotometric measurement of the oxidation of 2,20-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) showed a significant rise in laccase activity during PCMX elimination. Furthermore, with the use of bioindicators from different ecosystems (Daphtoxkit F and Phytotoxkit), it was revealed that the biodegradation process of PCMX had a detoxifying nature.

INFLUENCE OF CLIPPING HEIGHT ON THE NEUTRAL CARBOHYDRATE LEVELS OF ROOT EXUDATES OF ALFALFA PLANTS GROWN UNDER GNOTOBIOTIC CONDITIONS

1972 ◽  
Vol 52 (4) ◽  
pp. 643-649 ◽  
Author(s):  
R. A. HAMLEN ◽  
F. L. LUKEZIC ◽  
J. R. BLOOM
Keyword(s):  
Root Exudates ◽  
Dry Weight ◽  
Root Tissue ◽  
Minor Components ◽  
Flower Buds ◽  
Total Sugars ◽  
Spectral Techniques ◽  
Mass Spectral ◽  
Mature Leaves ◽  
Carbohydrate Levels

Influence of clipping height on neutral carbohydrate levels in root exudates of alfalfa grown gnotobiotically was investigated by gas-chromatographic and mass-spectral techniques. Exudates were obtained from plants that were lightly clipped (removal of flower buds), intermediately clipped (15 cm), and severely clipped (removal of all but four mature leaves). Glucose, inositol, sucrose, and four unidentified (U) components were detected. Fluctuations in the level of sugars were observed in exudates from two sampling periods. Glucose and U1 were most concentrated under light clipping. Levels of inositol and sucrose were maximum under intermediate clipping. Amounts of U3 were greatest from severely clipped plants, whereas levels of U5 remained constant at all cuttings. Concentration of U4 was lowest under severe clipping. U2, present in exudates from seedling plants, was not detected. Quantities of sugars released per gram of dry weight of root tissue were greater under severe clipping. U1 was the major component, with glucose, inositol, and sucrose minor components of the total sugars.

Remarkable kinetic stability of α-thiocarbamoyl substituted 4-methoxybenzylcations

1998 ◽  
Vol 76 (12) ◽  
pp. 1910-1915 ◽  
Author(s):  
Robert A McClelland ◽  
Victoria E Licence ◽  
John P Richard ◽  
Kathleen B Williams ◽  
Shrong-Shi Lin
Keyword(s):  
Key Words ◽  
Strong Interaction ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Visible Absorption ◽  
Methyl Group ◽  
Thioamide Group ◽  
Azide Ion ◽  
Uv Visible ◽  
Leaving Groups

4-Methoxybenzyl cations bearing α-(N,N-dimethylcarbamoyl) and α-(N,N-dimethylthiocarbamoyl) substituents have been generated photochemically upon irradiation of precursors with pentafluorobenzoate or 4-methoxybenzoate leaving groups. The ions have been observed with flash photolysis in 40:60 acetonitrile:water and in 50:50 methanol:water, and rate constants were measured for their decay in solvent alone and for their capture by azide ion. The cations so studied and their lifetimes in 40% acetonitrile are 6, ArC+H-CONMe2, 0.6 μs; 2, ArC+H-CSNMe2, 7 ms; and 4, ArC+(CH3)-CSMe2, 6 ms, where Ar = 4-MeOC6H4. The cation 4 reacts with solvent by elimination of a proton from the α-methyl group, and the rate constant for solvent addition must be less than 1 s-1. The CSNMe2 substituted cations are 105-107-fold longer lived than analogs where the thioamide group has been replaced with an α-methyl. The UV-visible absorption spectra of these two cations also show significant differences from those of typical 4-methoxybenzyl cations. Thus, both the lifetimes and spectra point to a strong interaction of the benzylic centre with the thioamide group. Key words: flash photolysis, thiocarbamoyl stabilized carbocation, photosolvolysis.

scholarly journals A novel member of the GCN5-related N-acetyltransferase superfamily from Caenorhabditis elegans preferentially catalyses the N-acetylation of thialysine [S-(2-aminoethyl)-L-cysteine]

2004 ◽  
Vol 384 (1) ◽  
pp. 129-137 ◽  
Author(s):  
Benjamin ABO-DALO ◽  
Dieudonne NDJONKA ◽  
Francesco PINNEN ◽  
Eva LIEBAU ◽  
Kai LÜERSEN
Keyword(s):  
Caenorhabditis Elegans ◽  
Reversed Phase ◽  
Open Reading Frame ◽  
Side Chain ◽  
Homologous Gene ◽  
Reversed Phase Hplc ◽  
Nematode Caenorhabditis Elegans ◽  
Reading Frame ◽  
Considerable Similarity ◽  
C Elegans

The putative diamine N-acetyltransferase D2023.4 has been cloned from the model nematode Caenorhabditis elegans. The 483 bp open reading frame of the cDNA encodes a deduced polypeptide of 18.6 kDa. Accordingly, the recombinantly expressed His6-tagged protein forms an enzymically active homodimer with a molecular mass of approx. 44000 Da. The protein belongs to the GNAT (GCN5-related N-acetyltransferase) superfamily, and its amino acid sequence exhibits considerable similarity to mammalian spermidine/spermine-N1-acetyltransferases. However, neither the polyamines spermidine and spermine nor the diamines putrescine and cadaverine were efficiently acetylated by the protein. The smaller diamines diaminopropane and ethylenediamine, as well as L-lysine, represent better substrates, but, surprisingly, the enzyme most efficiently catalyses the N-acetylation of amino acids analogous with L-lysine. As determined by the kcat/Km values, the C. elegans N-acetyltransferase prefers thialysine [S-(2-aminoethyl)-L-cysteine], followed by O-(2-aminoethyl)-L-serine and S-(2-aminoethyl)-D,L-homocysteine. Reversed-phase HPLC and mass spectrometric analyses revealed that N-acetylation of L-lysine and L-thialysine occurs exclusively at the amino moiety of the side chain. Remarkably, heterologous expression of C. elegans N-acetyltransferase D2023.4 in Escherichia coli, which does not possess a homologous gene, results in a pronounced resistance against the anti-metabolite thialysine. Furthermore, C. elegans N-acetyltransferase D2023.4 exhibits the highest homology with a number of GNATs found in numerous genomes from bacteria to mammals that have not been biochemically characterized so far, suggesting a novel group of GNAT enzymes closely related to spermidine/spermine-N1-acetyltransferase, but with a distinct substrate specificity. Taken together, we propose to name the enzyme ‘thialysine Nε-acetyltransferase’.

scholarly journals 2C-B-Fly-NBOMe Metabolites in Rat Urine, Human Liver Microsomes and C. elegans: Confirmation with Synthesized Analytical Standards

Metabolites ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 775
Author(s):  
Jitka Nykodemová ◽  
Anna Šuláková ◽  
Petr Palivec ◽  
Hedvika Češková ◽  
Silvie Rimpelová ◽  
...  
Keyword(s):  
Phase I ◽  
Human Liver ◽  
Liver Microsomes ◽  
Human Liver Microsomes ◽  
Diagnostic Tools ◽  
Cunninghamella Elegans ◽  
Rat Urine ◽  
C Elegans ◽  
Fragmentation Patterns

Compounds from the N-benzylphenethylamine (NBPEA) class of novel psychoactive substances are being increasingly utilized in neurobiological and clinical research, as diagnostic tools, or for recreational purposes. To understand the pharmacology, safety, or potential toxicity of these substances, elucidating their metabolic fate is therefore of the utmost interest. Several studies on NBPEA metabolism have emerged, but scarce information about substances with a tetrahydrobenzodifuran (“Fly”) moiety is available. Here, we investigated the metabolism of 2-(8-bromo-2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b’]difuran-4-yl)-N-(2-methoxybenzyl)ethan-1-amine (2C-B-Fly-NBOMe) in three different systems: isolated human liver microsomes, Cunninghamella elegans mycelium, and in rats in vivo. Phase I and II metabolites of 2C-B-Fly-NBOMe were first detected in an untargeted screening and identified by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Several hypothesized metabolites were then synthesized as reference standards; knowledge of their fragmentation patterns was utilized for confirmation or tentative identification of isomers. Altogether, thirty-five phase I and nine phase II 2C-B-Fly-NBOMe metabolites were detected. Major detected metabolic pathways were mono- and poly-hydroxylation, O-demethylation, oxidative debromination, and to a lesser extent also N-demethoxybenzylation, followed by glucuronidation and/or N-acetylation. Differences were observed for the three used media. The highest number of metabolites and at highest concentration were found in human liver microsomes. In vivo metabolites detected from rat urine included two poly-hydroxylated metabolites found only in this media. Mycelium matrix contained several dehydrogenated, N-oxygenated, and dibrominated metabolites.

scholarly journals Mass Spectrometry-Based Characterization of New Spirolides from Alexandrium ostenfeldii (Dinophyceae)

Marine Drugs ◽  
2020 ◽  
Vol 18 (10) ◽  
pp. 505
Author(s):  
Joyce A. Nieva ◽  
Jan Tebben ◽  
Urban Tillmann ◽  
Sylke Wohlrab ◽  
Bernd Krock
Keyword(s):  
Mass Spectrometry ◽  
High Resolution Mass Spectrometry ◽  
Molecular Ions ◽  
Ring System ◽  
The Other ◽  
Spectral Techniques ◽  
Mass Spectral ◽  
Alexandrium Ostenfeldii ◽  
Different Strains

Spirolides belong to a group of marine phycotoxins produced by the marine planktonic dinophyte Alexandrium ostenfeldii. Composed of an imine moiety and a spiroketal ring system within a macrocylcle, spirolides are highly diverse with toxin types that vary among different strains. This study aims to characterize the spirolides from clonal A. ostenfeldii strains collected from The Netherlands, Greenland and Norway by mass spectral techniques. The structural characterization of unknown spirolides as inferred from high-resolution mass spectrometry (HR-MS) and collision induced dissociation (CID) spectra revealed the presence of nine novel spirolides that have the pseudo-molecular ions m/z 670 (1), m/z 666 (2), m/z 696 (3), m/z 678 (4), m/z 694 (5), m/z 708 (6), m/z 720 (7), m/z 722 (8) and m/z 738 (9). Of the nine new spirolides proposed in this study, compound 1 was suggested to have a truncated side chain in lieu of the commonly observed butenolide ring in spirolides. Moreover, there is indication that compound 5 might belong to new spirolide subclasses with a trispiroketal ring configuration having a 6:5:6 trispiroketal ring system. On the other hand, the other compounds were proposed as C- and G-type SPX, respectively. Compound 7 is proposed as the first G-type SPX with a 10-hydroxylation as usually observed in C-type SPX. This mass spectrometry-based study thus demonstrates that structural variability of spirolides is larger than previously known and does not only include the presence or absence of certain functional groups but also involves the triketal ring system.

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