69 research outputs found

    Herbimycins D-F, Ansamycin Analogues from \u3cem\u3eStreptomyces\u3c/em\u3e sp. RM-7-15

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    Bacterial strains belonging to the class actinomycetes were isolated from the soil near a thermal vent of the Ruth Mullins coal fire (Appalachian mountains of Eastern Kentucky). High resolution electrospray ionization mass spectrometry (HR-ESI-MS) and ultraviolet (UV) absorption profiles of metabolites from one of the isolates (Streptomyces sp. RM-7-15) revealed the presence of a unique set of metabolites ultimately determined to be herbimycins D-F (1–3). In addition, herbimycin A (4), dihydroherbimycin A (TAN 420E) (7), and the structurally distinct antibiotic bicycylomycin were isolated from the crude extract of Streptomyces sp. RM-7-15. Herbimycins A, D-F (1–3) displayed comparable binding affinities to the Hsp90α. While the new analogues were found to be inactive in cancer cell cytotoxicity and antimicrobial assays, they may offer new insights in the context of non-toxic ansamycin-based Hsp90 inhibitors for the treatment of neurodegenerative disease

    The Native Production of the Sesquiterpene Isopterocarpolone by \u3cem\u3eStreptomyces\u3c/em\u3e sp. RM-14-6

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    We report the production, isolation and structure elucidation of the sesquiterpene isopterocarpolone from an Appalachian isolate Streptomyces species RM-14-6. While isopterocarpolone was previously put forth as a putative plant metabolite, this study highlights the first native bacterial production of isopterocarpolone and the first full characterisation of isopterocarpolone using 1D and 2D NMR spectroscopy and HR-ESI mass spectrometry. Considering the biosynthesis of closely related metabolites (geosmin or 5-epiaristolochene), the structure of isopterocarpolone also suggests the potential participation of one or more unique enzymatic transformations. In this context, this work also sets the stage for the elucidation of potentially novel bacterial biosynthetic machinery

    Spoxazomicin D and Oxachelin C, Potent Neuroprotective Carboxamides from the Appalachian Coal Fire-Associated Isolate \u3cem\u3eStreptomyces\u3c/em\u3e sp. RM-14- 6

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    The isolation and structure elucidation of six new bacterial metabolites [spoxazomicin D (2), oxachelins B and C (4, 5), and carboxamides 6–8] and 11 previously reported bacterial metabolites (1, 3, 9–12a, and 14–18) from Streptomyces sp. RM-14-6 is reported. Structures were elucidated on the basis of comprehensive 1D and 2D NMR and mass spectrometry data analysis, along with direct comparison to synthetic standards for 2, 11, and 12a,b. Complete 2D NMR assignments for the known metabolites lenoremycin (9) and lenoremycin sodium salt (10) were also provided for the first time. Comparative analysis also provided the basis for structural revision of several previously reported putative aziridine-containing compounds [exemplified by madurastatins A1, B1, C1 (also known as MBJ-0034), and MBJ-0035] as phenol-dihydrooxazoles. Bioactivity analysis [including antibacterial, antifungal, cancer cell line cytotoxicity, unfolded protein response (UPR) modulation, and EtOH damage neuroprotection] revealed 2 and 5 as potent neuroprotectives and lenoremycin (9) and its sodium salt (10) as potent UPR modulators, highlighting new functions for phenol-oxazolines/salicylates and polyether pharmacophores

    Matrix isolation and spectroscopic properties of the methylsulfinyl radical CH3(O)S˙

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    Publikacja w ramach programu Royal Society of Chemistry "Gold for Gold" 2013 finansowanego przez Uniwersytet ŁódzkiThe atmospherically highly relevant methylsulfinyl radical CH3(O)S˙ was generated thermally under flash pyrolysis conditions and isolated in Ar matrices at 10 K; the allyl radical is a byproduct. CH3(O)S˙ and its D3- and 13C-isotopologues were characterized through the excellent agreement between experimental and computed IR and UV/Vis spectra

    Transcending Sovereignty: Locating Indigenous Peoples in Transboundary Water Law

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