An acinar morphogenesis inhibitor named fusarisetin A (1) that possesses both an unprecedented carbon skeleton and a new pentacyclic ring system has been identified from an in-house fractionated fungal library using a three-dimensional matrigel-induced acinar morphogenesis assay system. The structure of 1 was determined in detail by NMR and circular dichroism spectroscopy, X-ray analysis, and chemical reaction experiments.
The objective of this research was to evaluate the effect of bamboo species and resin content on the physical and mechanical properties of oriented strand boards (OSBs) prepared from steam-treated bamboo strands. The strands from three species of Indonesian bamboo, namely Andong (Gigantochloa verticillata), Betung (Dendrocalamus asper), and Ampel (Bambusa vulgaris), were steamed at 126 °C for 1 h at a pressure of 0.14 MPa. Three-layered OSBs with the core layer oriented perpendicularly to the face layers were prepared by bonding them together with 3 to 5% methylene diphenyldiisocyanate (MDI) resin based on ovendried strands and with the addition of 1% paraffin. The strand compositions for the face, core, and back layers were 25%, 50%, and 25%, respectively. The slenderness ratios and aspect ratios of the strands ranged from 71.02 to 76.60 and from 2.96 to 3.02, respectively. The physical and mechanical properties of the OSBs fabricated from Andong and Betung were better than those from Ampel, and the properties of all OSBs were improved by increasing their resin content. OSBs from Betung with 3 to 5% resin content and those from Andong and Ampel with 4 to 5% resin content showed strength retention of more than 50%, which means they can be used for exterior structural applications. Except for OSBs fabricated from Ampel with 3% resin content, the properties of all OSBs prepared in this study were higher than the minimum values required by the CSA O437.0 (grade O-1) standard (2011).
Analysis of the genome sequence of Streptomyces sp. KCB13F003 showed the presence of a cryptic gene cluster encoding flavin-dependent halogenase and nonribosomal peptide synthetase. Pleiotropic approaches using multiple culture media followed by LC-MS-guided isolation and spectroscopic analysis enabled the identification of two new chlorinated cyclic hexapeptides, ulleungmycins A and B (1 and 2). Their structures, including absolute configurations, were determined by 1D and 2D NMR techniques, advanced Marfey's analysis, and GITC derivatization. The new peptides, featuring unusual amino acids 5-chloro-l-tryptophan and d-homoleucine, exhibited moderate antibacterial activities against Gram-positive pathogenic bacteria including methicillin-resistant and quinolone-resistant Staphylococcus aureus.
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