Hosimosines A-E, structurally diverse cytisine derivatives from the seeds of Ormosia hosiei Hemsl. et Wils.

Ormosia hosiei Hemsl. et Wils (Fabaceae family) is an arbor species endemic to China. The seeds of O. hosiei have been used as traditional Chinese medicine to treat hernia, abdominal pain, blood stasis and amenorrhea. Cytisine-like and angustifoline type alkaloids were main components identified from this plant. In our research on the bioactive alkaloids from the promising Chinese medicinal plants, four new angustifoline type alkaloids (1-4) and a new cytisine-like alkaloid (5), named hosimosine A-E, together with 13 known analogues (6-18) were isolated from the seeds of O. hosiei. Their structures were elucidated by the extensive spectroscopic methods, especially the interpretation of NMR spectra and specific rotations, along with the methods of NMR and ECD calculation. Compounds 1-4 were identified as two pairs of epimers, whose relative configurations were deduced from density functional theory (DFT) calculations of NMR chemical shifts and DP4+ analysis, and absolute configurations were determined by comparison of their experimental and theoretical ECD spectra. Compound 5 displayed two sets of NMR data caused by the existence of tautomeric forms. Compounds 14, 17 and 18 were determined to be enantiomers of literature compounds. Some of the isolates exhibited moderate cytotoxic effects against HepG2, A2780 and MCF-7 cells.

Dearomative 1,4-difunctionalization of naphthalenes via palladium-catalyzed tandem Heck/Suzuki coupling reaction.

Dearomative functionalization reactions represent an important strategy for the synthesis of valuable three-dimensional molecules from simple planar aromatics. Naphthalene is a challenging arene towards transition-metal-catalyzed dearomative difunctionalization reactions. Reported herein is an application of naphthalene as a masked conjugated diene in a palladium-catalyzed dearomative 1,4-diarylation or 1,4-vinylarylation reaction via tandem Heck/Suzuki sequence. Three types of 1,4-dihydronaphthalene-based spirocyclic compounds are achieved in excellent regio- and diastereoselectivities. Key to this transformation is the inhibition of a few competitive side reactions, including intramolecular naphthalenyl C-H arylation, intermolecular Suzuki cross-coupling, dearomative 1,2-difunctionalization, and dearomative reductive-Heck reaction. Density functional theory (DFT) calculations imply that the facile exergonic dearomative insertion of a naphthalene double bond disrupts the sequence of direct Suzuki coupling, leading to the tandem Heck/Suzuki coupling reaction. The observed regioselectivity towards 1,4-difunctionalization is due to the steric repulsions between the introduced aryl group and the spiro-scaffold in 1,2-difunctionalization.

3,3'-Disubstituted Oxindoles Formation via Copper-Catalyzed Arylboration and Arylsilylation of Alkenes.

Arylboration and arylsilylation reactions of N-(2-iodoaryl)acrylamides with bis(pinacolato)-diboron (B2pin2) or PhMe2Si-Bpin are developed by using simple CuOAc as the sole catalyst. A range of boron- or silane-bearing 3,3'-disubstituted oxindoles are obtained in moderate to excellent yields. The reaction is proposed to proceed via a domino sequence involving intermolecular olefin borylcupration or silylcupration followed by intramolecular coupling of an alkyl-Cu intermediate with aryl iodide.

Screening Serum Differential Proteins for Childhood Asthma at Different Control Levels by Isobaric Tags for Relative and Absolute Quantification-based Proteomic Technology.

Objective To screen serum differential proteins for childhood asthma at different control levels,which provided the basis for the prevention and treatment of childhood asthma. Methods Isobaric tags for relative and absolute quantification,two-dimensional liquid chromatography,nanoelectrospray ionization,and high-resolution tandem mass spectrometry using the hybrid quadrupole time-of-flight platform was used to screen the differential proteins in serum samples from pediatric patients with controlled,partly controlled,or uncontrolled childhood asthma. Differential proteins were validated using enzyme-linked immunosorbent assay (ELISA). Results A total of 260 expressed proteins were identified. Among them 57 differentially expressed proteins were found among the different control levels of childhood asthma (fold<0.8 or fold>1.2). The differentially expressed proteins were involved mainly in 21 biological processes and 8 molecular functions and were located in 17 cellular components. ELISA showed that the serum vitronectin level was significantly higher in controlled group [(573.92±412.43) µg/ml] than in uncontrolled group[(382.27±238.64)]µg/ml (P=0.0399). Conclusion We identified 57 differential proteins for childhood asthma at different control levels,which may be used as potential biological targets for the control of childhood asthma.

MsmK, an ATPase, Contributes to Utilization of Multiple Carbohydrates and Host Colonization of Streptococcus suis.

Acquisition and metabolism of carbohydrates are essential for host colonization and pathogenesis of bacterial pathogens. Different bacteria can uptake different lines of carbohydrates via ABC transporters, in which ATPase subunits energize the transport though ATP hydrolysis. Some ABC transporters possess their own ATPases, while some share a common ATPase. Here we identified MsmK, an ATPase from Streptococcus suis, an emerging zoonotic bacterium causing dead infections in pigs and humans. Genetic and biochemistry studies revealed that the MsmK was responsible for the utilization of raffinose, melibiose, maltotetraose, glycogen and maltotriose. In infected mice, the msmK-deletion mutant showed significant defects of survival and colonization when compared with its parental and complementary strains. Taken together, MsmK is an ATPase that contributes to multiple carbohydrates utilization and host colonization of S. suis. This study gives new insight into our understanding of the carbohydrates utilization and its relationship to the pathogenesis of this zoonotic pathogen.

A novel quorum sensing system co-regulated by chromosome- and plasmid-encoded genes in Serratia marcescens H30.

The key genes, SpnI and SpnR, involved in AI-1-quorum sensing system of Serratia marcescens strain H30 were cloned and localized using specific primers (5'-CTTGAACTGTTTGACGTCAGC-3' and 5'-AGCGGCCAGGTAATAACTGA-3', 5'-GCCTTCAATGAAAATCAGACC-3' and 5'-TGTCGCTGTGATAAGCTCCA-3') designed according to the nucleic acid sequences published at NCBI (accession no. AB234869). The PCR result demonstrated that the genes SpnI and SpnR were located on the bacterial chromosome and plasmid, respectively. This was also confirmed by Southern blotting using an internal fragment (379 bp) from SpnR gene as a probe. These results imply a new type quorum sensing regulation system that had never been reported previously.

Cloning and characterizations of the Serratia marcescens metK and pfs genes involved in AI-2-dependent quorum-sensing system.

Serratia marcescens utilizes two types of quorum-sensing signal molecules: N-acyl homoserine lactones and furanosyl borate diester (AI-2). S-adenosylmethionine synthetase (METK), S-adenosylhomocysteine nucleosidase (PFS), and S-ribosylhomocysteinase (LUXS) are three key enzymes in the biosynthetic pathway leading to AI-2 production. The sequence of luxS gene was published at NCBI (Accession number: EF164926). So in this study, Serratia marcescens metK and pfs genes were successfully cloned with inverse PCR. The results show that the ORF lengths of metK and pfs are 1155 and 702 bp, and encode proteins of 384 and 233 residues. Their molecular weights and isoelectric points are 41.85 kD and 5.50; 27.67 kD and 5.56, which are acidic proteins judging from the calculated pI values. Expression products of two genes with pET28a((+)) system exhibited molecular weights in sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis comparable with a theoretical estimation. The sequences of these two genes were conferred China patent application numbers CN 200710048016.X and CN 200710048015.5, respectively.