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Arx AND Polyphenol

Timothy R Valentic, David R Jackson, Sean F Brady, Shiou-Chuan Tsai
Arixanthomycins are pentangular polyphenols (PP) with potent antiproliferative activities that were discovered through the heterologous expression of environmental DNA-derived gene clusters. The biosynthesis of arixanthomycin and other PPs is unusual because it requires several novel type II polyketide synthase (PKS) enzymes for its complete maturation. Most type II PKSs contain a ketoreductase (KR) that mediates the C7-C12 first ring cyclization and C-9 reduction. In contrast, based on previous studies of product analysis and genome mining, the arixanthomycin (ARX) gene cluster harbors a C-11 reducing KR (ARX 27), a C9-C14 first-ring aromatase/cyclase (ARX 19), and an unprecedented C-17 and C-19 reducing KR (ARX 21)...
December 16, 2016: ACS Chemical Biology
Hahk-Soo Kang, Sean F Brady
Soil microbiomes are a rich source of uncharacterized natural product biosynthetic gene clusters. Here we use short conserved biosynthetic gene sequences (natural product sequence tags) amplified from soil microbiomes as phylogenetic markers to correlate genotype to chemotype and target the discovery of novel bioactive pentangular polyphenols from the environment. The heterologous expression of an environmental DNA-derived gene cluster (the ARX cluster), whose ketosynthase beta (KSβ) sequence tag was phylogenetically distinct from any known KSβ sequence, led to the discovery of the arixanthomycins...
June 20, 2014: ACS Chemical Biology
Carme Plumed-Ferrer, Kati Väkeväinen, Heli Komulainen, Maarit Rautiainen, Annika Smeds, Jan-Erik Raitanen, Patrik Eklund, Stefan Willför, Hanna-Leena Alakomi, Maria Saarela, Atte von Wright
The antimicrobial effects of the wood-associated polyphenolic compounds pinosylvin, pinosylvin monomethyl ether, astringin, piceatannol, isorhapontin, isorhapontigenin, cycloXMe, dHIMP, ArX, and ArXOH were assessed against both Gram-negative (Salmonella) and Gram-positive bacteria (Listeria monocytogenes, Staphylococcus epidermidis, Staphylococcus aureus) and yeasts (Candida tropicalis, Saccharomyces cerevisiae). Particularly the stilbenes pinosylvin, its monomethyl ether and piceatannol demonstrated a clear antimicrobial activity, which in the case of pinosylvin was present also in food matrices like sauerkraut, gravlax and berry jam, but not in milk...
June 3, 2013: International Journal of Food Microbiology
Yicheng Ni, Dieter Huyghe, Kristin Verbeke, Peter A de Witte, Johan Nuyts, Luc Mortelmans, Feng Chen, Guy Marchal, Alfons M Verbruggen, Guy M Bormans
PURPOSE: We have labelled hypericin, a polyphenolic polycyclic quinone found in St. John's wort (Hypericum perforatum), with( 123)I and evaluated mono-[(123)I]iodohypericin (MIH) as a potential necrosis-avid diagnostic tracer agent. METHODS: MIH was prepared by an electrophilic radioiodination method. The new tracer agent was evaluated in animal models of liver infarction in the rat and heart infarction in the rabbit using single-photon emission computed tomography (SPECT), triphenyltetrazolium chloride (TTC) histochemical staining, serial sectional autoradiography and microscopy, and radioactivity counting techniques...
May 2006: European Journal of Nuclear Medicine and Molecular Imaging
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