Prospects for tertiary structure prediction of RNA based on secondary structure information

We developed a method, called RNA Assembler using Secondary Structure Information Effectively (RASSIE), for predicting RNA tertiary structures using known secondary structure information. We attempted a fragment assembly-based method that uses a secondary structure-based fragment library. For several typical target structures such as stem-loops, bulge-loops, and 2-way junctions, our method provided numerous good quality candidate structures in less computational time than previously proposed methods. By using a high-resolution potential energy function, we were able to select good predicted structures from candidate structures. This method of efficient conformational search and detailed structure evaluation using high-resolution potential is potentially useful for the tertiary structure prediction of RNA.     

Resveratrol-derived stilbenoids and biological activity evaluation of seed extracts of Cenchrus echinatus L

A phytochemical study of the ethyl acetate fractions from the partition of seeds and roots methanol extracts of Cenchrus echinatus L. led to the isolation of three resveratrol-derived stilbenoids: pallidol (1), carasiphenol C (2) and nepalensinol B (3). The results of a topic anti-inflammatory evaluation, DPPH assay and antiproliferative activity against adenocarcinoma cells (Caco 2) are described.     

C3-symmetric trisimidazoline-catalyzed enantioselective bromolactonization of internal alkenoic acids

A method for conducting enantioselective bromolactonization reactions of trisubstituted alkenoic acids, using the C(3)-symmetric trisimidazoline 1 and 1,3-dibromo-5,5-dimethyl hydantoin as a bromine source, has been developed. The process generates chiral δ-lactones that contain a quaternary carbon. The results of studies probing geometrically different olefins show that (Z)-olefins rather than (E)-olefins are favorable substrates for the process. The method is not only applicable to acyclic olefin reactants but can also be employed to transform cyclic trisubstituted olefins into chiral spirocyclic lactones. Finally, the synthetic utility of the newly developed process is demonstrated by its application to a concise synthesis of tanikolide, an antifungal marine natural product.     

Three lanostane triterpenoids with antitrypanosomal activity from the fruiting body of Hexagonia tenuis

During the search for new antitrypanosomal drug leads, three new antitrypanosomal compounds, hexatenuins A–C (1–3), were isolated from the fruiting body of Hexagonia tenuis. 1 and 3 possessed an unusual malonate half-ester functional group at C-3 position, and 1 and 2 had a spirostructure in the side-chain. Their structures were elucidated using MS analyses, extensive 2D-heteronuclear NMR data interpretation. Compounds 1–3 showed in vitro antitrypanosomal activity against Trypanosoma brucei brucei with IC₅₀ values of 0.57, 8.60 and 5.62 μg/ml, respectively.     

Einflu? verschiedener Salze auf die mechanischen EIgenschaften von homogenen Poly-(2-hydroxy?thylmethacrylat)-Hydrogelen

Ohne Zusammenfassung     

Fabrication of flower-shaped Bi2O3 superstructure by a facile template-free process

A novel flower-shaped Bi₂O₃ superstructure has been successfully synthesized by calcination of the precursor, which was prepared via a citric acid assisted hydrothermal process. The precursor and Bi₂O₃ were characterized with respect to morphology, crystal structure and elemental chemical state by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was shown that both the precursor and Bi₂O₃ flower-shaped superstructure were constructed of numerous nanosheets while the nanosheets consisted of a great deal of nanoparticles. Furthermore, key factors for the formation of the superstructures have been proposed; a mechanism for the growth of the superstructure has been presented based on the FESEM investigation of different growth stages.