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DNAzyme-based chemiluminescence assay exhibits excellent performance in bioanalysis but their operation in acid conditions remains challengeable. Herein, we constructed an acid-improved DNAzyme-based isothermal enzyme-free concatenated DNA circuit with significantly reduced background and simultaneously improved signal-to-noise ratio for miRNA detection. The chemiluminescence miRNA assay is composed of catalyzed hairpin assembly (CHA), hybridization chain reaction (HCR), and hemin/G-quadruplex DNAzyme units. The analyte initiates the self-assembly of CHA hairpins into numerous dsDNA, which triggers the subsequent autonomous cross-opening of HCR hairpins to generate long nanowires consisting of the hemin/G-quadruplex DNAzyme. The DNAzyme catalyzes the oxidation of luminol by hydrogen peroxide for the cascaded amplified chemiluminescence signal. The acid-improved property was demonstrated to be closely associated with the low catalytic activity of aggregated hemin under acidic conditions and the remained multiple amplified signal through concatenated DNA circuit. The general DNA circuit exhibited high sensitivity for miRNA-21 detection and chemiluminescence imaging under acidic conditions with a recognition hairpin. The acid-improved DNAzyme-based concatenated DNA circuit is promising to expand the application of chemiluminescence assay and provide a valuable strategy for early diagnosis and prognosis of cancer.

A new α-pyrone derivative1, along with four known congeners 2, 3, 4 and 5, were isolated from the solid-substrate fermentation medium of the endophytic fungus Pestalotiopsis microspore isolated from the branch of Taxus chinensis. Their structures and relative configurations were elucidated by extensive spectroscopic analysis. The cytotoxic activities of the isolated α-pyrone derivatives against two tumor cell lines as well as compound 1 ’ s antimicrobial activity against three bacteria and three plant-pathogenic strains were evaluated. No antimicrobial activity was observed for compound 1. The cytotoxicity against Caski and He L a tumor cell lines w as insignificant. To our surprise, the known compound 4 showed significant gibberellin synergistic activity towards Distylium chinense seeds.

(-)-(10E,15S)-10,11-Dehydrocurvularin (1), produced from an associated-fungus of Scolopendra subspinipes mutilans on a gram scale, was microbiologically converted to curvularin (2) and 5-methoxycurvularin (3) by Antrodiella semisupina in 61% totally isolated yield. The structures of these compounds were elucidated on the basis of spectroscopic and mass spectrometric analysis. The undescribed assignments of 1H and 13C NMR spectral data for 5-methoxycurvularin (2) has now been explicitly provided. The cytotoxic activities of compounds 1-3 against four human cancer cell lines were evaluated. Dehydrocurvularin (1) showed moderate cytotoxicity against Caski and Hep-G2, and curvularin (2) was selectively cytotoxic against MDA-MB-231.