Four new mycotoxins of Aspergillus clavatus related to tryptoquivaline

Buechi, George; Luk, Kin Chun; Kobbe, B; Townsend, James M.

doi:10.1021/jo00422a015

Cited by 79 publications

(43 citation statements)

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“…The chemical shifts of the N-hydroxylated aminal unit were in agreement with those reported for related structures. [5][6][7] Representative HMBC correlations are summarized in Figure 2. The longwave UV absorption maximum is hypsochromically shifted by about 10 nm in N-hydroxylated compound 2, which was also reported for N-hydroxylated anilines.…”

Section: Fermentation and Isolationmentioning

confidence: 99%

Omphalotins E–I, Five Oxidatively Modified Nematicidal Cyclopeptides from Omphalotus olearius

et al. 2009

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Omphalotins E–I, oxidatively modified cyclic dodecapeptides, were isolated from mycelial extracts of the basidiomycete Omphalotus olearius, and their structures were determined by NMR spectroscopic and MS methods. Four of the five omphalotins contained an unprecedented N‐hydroxylated tricyclic tryptophan derivative. All compounds exhibited strong and selective nematicidal activity against the plant pathogen Meloidogyne incognita with LD90 values between 2 and 5 μg mL–1. Cytotoxic activities were not detected up to 50 μg mL–1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Fermentation and Isolationmentioning

confidence: 99%

Omphalotins E–I, Five Oxidatively Modified Nematicidal Cyclopeptides from Omphalotus olearius

et al. 2009

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“…It was found that the production rates of those two metabolites were affected by the activity of the pectinolytic enzymes [23,24]. The ascomycete Aspergillus clavatus is mainly studied in relation to the production of secondary metabolites [25,26] and the toxin patulin which may be associated with disease in humans and animals [27]. …”

Section: Introductionmentioning

confidence: 99%

Degradation of different pectins by fungi: correlations and contrasts between the pectinolytic enzyme sets identified in genomes and the growth on pectins of different origin

et al. 2012

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BackgroundPectins are diverse and very complex biomolecules and their structure depends on the plant species and tissue. It was previously shown that derivatives of pectic polymers and oligosaccharides from pectins have positive effects on human health. To obtain specific pectic oligosaccharides, highly defined enzymatic mixes are required. Filamentous fungi are specialized in plant cell wall degradation and some produce a broad range of pectinases. They may therefore shed light on the enzyme mixes needed for partial hydrolysis.ResultsThe growth profiles of 12 fungi on four pectins and four structural elements of pectins show that the presence/absence of pectinolytic genes in the fungal genome clearly correlates with their ability to degrade pectins. However, this correlation is less clear when we zoom in to the pectic structural elements.ConclusionsThis study highlights the complexity of the mechanisms involved in fungal degradation of complex carbon sources such as pectins. Mining genomes and comparative genomics are promising first steps towards the production of specific pectinolytic fractions.

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“…This compound had not been reported previously as a from Fusarium martii (2), colletruncoic acid methyl ester (2) metabolite of A. niger. Other fractions from the chromatogram from Colletotrichum truncatum (3), kotanin (3) and demethyl kotanin (4) from Aspergillus clavatus (4,5), orlandin (5) from A. niger (6), siderin (6), the monomer of kotanin, from A. variecolor (7,8), and the desertorins A, B, and C (7-9, respectively) from Emericella desertorurn ( A . nidulans group) (9).…”

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Confirmation of the polyketide origin of kotanin by incorporation of [1,2-¹³C₂]acetate

Stothers¹,

Stoessl²

1988

Can. J. Chem.

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Incorporation experiments with [ l ,2-'3C2]acetate establish that the biosynthesis of kotanin, a dimeric 5-rnethylcoumarin, proceeds through a polyketide pathway and, therefore, represents an exception to Turner's rule regarding the relative lengths of the uncyclized residues of polyketide chains. The previous I3C signal assignments are also revised.J. B. STOTHERS ET ALBERT STOESSL. Can. J. Chern. 66 28 16 (1988).Des exp6riences d'incorporation du acetate [I3C2-1 ,2] ont permis de dtrnontrer que la biosynthtse de la kotanine, un dirntre de la mkthyl-5 cournarine, se produit par le biais d'un polycttide et qu'elle correspond donc i une exception h la rtgle de Turner concernant les longueurs relatives des rksidus non-cyclists des chaines polycttides. On a aussi revise les attributions antkrieures des signaux relatifs au 13c.[Traduit par la revue]Fungal metabolites whose structures are in real or apparent in the expectation of isolating orlandin (5) as the labelled breach of Turner's rule (1) that "the uncyclized residues from product. In a preliminary cold run, however, chromatography the methyl ends of polyketide chains are never shorter than of the culture extract furnished crystalline kotanin (3) in good residues from the carboxyl end of the chain" include marticin (1) yield. This compound had not been reported previously as a from Fusarium martii (2), colletruncoic acid methyl ester (2) metabolite of A. niger. Other fractions from the chromatogram from Colletotrichum truncatum (3), kotanin (3) and demethyl kotanin (4) from Aspergillus clavatus (4, 5), orlandin (5) from A. niger (6), siderin (6), the monomer of kotanin, from A. variecolor (7,8), and the desertorins A, B, and C (7-9, respectively) from Emericella desertorurn ( A . nidulans group) (9). Another group of compounds comprises the benzoisochromane quinones, such as actinorhodin (10) and granaticin (1 l), whose relevant structural moieties (12) have been shown to be of polyketide origin by extensive biosynthetic studies (10, 11). The latter compounds, however, are metabolites of actinomycetes, that is, prokaryotic organisms which may not be encompassed by the rule. Of the true fungal metabolites marticin has been proven (2, 12) to be of mixed polyketide and tricarboxylic acid cycle origin, which accounts for the apparent anomaly. Of the others, only siderin (6) has been the subject of an experimental biosynthetic study. It was found (7) that A. variecolor cultures incorporated sodium [2-14Cl]acetate into 6 with 0.75% efficiency. Kuhn-Roth degradation of the labelled siderin placed 25.8% of its total radioactivity into the 5-methyl group and the excess, over the expected result of uniform incorporation (20% at each of 5 sites), was very plausibly ascribed to the starter effect as frequently seen in polyketide biosynthesis. Unfortunately, lack of material precluded further degradative experiments that could have rendered this conclusion certain. Alternative interpretations of the data, therefore, could not be entirely discounted. For instance, it might b...

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Four new mycotoxins of Aspergillus clavatus related to tryptoquivaline

Cited by 79 publications

References 3 publications

Omphalotins E–I, Five Oxidatively Modified Nematicidal Cyclopeptides from Omphalotus olearius

Omphalotins E–I, Five Oxidatively Modified Nematicidal Cyclopeptides from Omphalotus olearius

Degradation of different pectins by fungi: correlations and contrasts between the pectinolytic enzyme sets identified in genomes and the growth on pectins of different origin

Confirmation of the polyketide origin of kotanin by incorporation of [1,2-¹³C₂]acetate

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Four new mycotoxins of Aspergillus clavatus related to tryptoquivaline

Cited by 79 publications

References 3 publications

Omphalotins E–I, Five Oxidatively Modified Nematicidal Cyclopeptides from Omphalotus olearius

Omphalotins E–I, Five Oxidatively Modified Nematicidal Cyclopeptides from Omphalotus olearius

Degradation of different pectins by fungi: correlations and contrasts between the pectinolytic enzyme sets identified in genomes and the growth on pectins of different origin

Confirmation of the polyketide origin of kotanin by incorporation of [1,2-13C2]acetate

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Confirmation of the polyketide origin of kotanin by incorporation of [1,2-¹³C₂]acetate