60 research outputs found

    (+)-Geodin from Aspergillus terreus.

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    The fungal metabolite (+)-geodin [systematic name: (2R)-methyl 5,7-dichloro-4-hydroxy-6'-methoxy-6-methyl-3,4'-dioxospiro[benzofuran-2,1'-cyclohexa-2',5'-diene]-2'-carboxylate], C(17)H(12)Cl(2)O(7), was isolated from Aspergillus terreus. The crystal structure contains two independent molecules in the asymmetric unit. Molecules denoted 1 interact through O-H...O hydrogen bonds creating chains of molecules parallel to the crystallographic 2(1) screw axis. Molecules denoted 2 interact through an O...Cl halogen bond, also creating chains of molecules parallel to the crystallographic 2(1) screw axis. Molecules 1 and 2 interact through another O...Cl halogen bond. The two molecules are similar but molecules 2 have a slightly more planar cyclohexadiene ring than molecules 1. The absolute structure of (+)-geodin has been unequivocally assigned with the spiro centre having the R configuration in both molecules. The structurally related (+)-griseofulvin has an S configuration at the spiro centre, a difference of potential biological and biosynthetic relevance

    On de-bunking “Fake News” in the post-truth era : how to reduce statistical error in research

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    The authors note with alarm that statistical noise caused by statistical incompetence is beginning to creep into research on cost overrun in public investment projects, contaminating research with work that does not meet basic standards of validity and reliability. The paper gives examples of such work and proposes three heuristics to root out the problem. First, researchers who are not statisticians, or do not have a strong background in statistics, should abstain from doing statistical analysis, and instead rely on more experienced colleagues, preferably professional statisticians. Second, journal referees should clearly state their level of statistical proficiency to journal editors, so these can set the right referee team. Finally, journal editors should make sure that at least one referee is capable of reviewing the statistical and methodological aspects of a paper. The work under review would have benefitted from observing these simple heuristics, as would any work based on statistical analysis.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and Logistic

    New species in Aspergillus section Terrei

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    Section Terrei of Aspergillus was studied using a polyphasic approach including sequence analysis of parts of the β-tubulin and calmodulin genes and the ITS region, macro- and micromorphological analyses and examination of extrolite profiles to describe three new species in this section. Based on phylogenetic analysis of calmodulin and β-tubulin sequences seven lineages were observed among isolates that have previously been treated as A. terreus and its subspecies by Raper & Fennell (1965) and others. Aspergillus alabamensis, A. terreus var. floccosus, A. terreus var. africanus, A. terreus var. aureus, A. hortai and A. terreus NRRL 4017 all represent distinct lineages from the A. terreus clade. Among them, A. terreus var. floccosus, A. terreus NRRL 4017 and A. terreus var. aureus could also be distinguished from A. terreus by using ITS sequence data. New names are proposed for A. terreus var. floccosus, A. terreus var. africanus, A. terreus var. aureus, while Aspergillus hortai is recognised at species level. Aspergillus terreus NRRL 4017 is described as the new species A. pseudoterreus. Also included in section Terrei are some species formerly placed in sections Flavipedes and Versicolores. A. clade including the type isolate of A. niveus (CBS 115.27) constitutes a lineage closely related to A. carneus. Fennellia nivea, the hypothesized teleomorph is not related to this clade. Aspergillus allahabadii, A. niveus var. indicus, and two species originally placed in section Versicolores, A. ambiguus and A. microcysticus, also form well-defined lineages on all trees. Species in Aspergillus section Terrei are producers of a diverse array of secondary metabolites. However, many of the species in the section produce different combinations of the following metabolites: acetylaranotin, asperphenamate, aspochalamins, aspulvinones, asteltoxin, asterric acid, asterriquinones, aszonalenins, atrovenetins, butyrolactones, citreoisocoumarins, citreoviridins, citrinins, decaturins, fulvic acid, geodins, gregatins, mevinolins, serantrypinone, terreic acid (only the precursor 3,6-dihydroxytoluquinone found), terreins, terrequinones, terretonins and territrems. The cholesterol-lowering agent mevinolin was found in A. terreus and A. neoafricanus only. The hepatotoxic extrolite citrinin was found in eight species: A. alabamensis, A. allahabadii, A. carneus, A. floccosus, A. hortai, A. neoindicus, A. niveus and A. pseudoterreus. The neurotoxic extrolite citreoviridin was found in five species: A. neoafricanus, A. aureoterreus, A. pseudoterreus, A. terreus and A. neoniveus. Territrems, tremorgenic extrolites, were found in some strains of A. alabamensis and A. terreus

    The Chemistry of Griseofulvin

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