4-Tosyl-1-oxa-4-aza­spiro­[4.5]deca-6,9-dien-8-one

In the mol­ecule of the title compound, C15H15NO4S, the two six-membered rings are almost parallel to each other [dihedral angle = 1.87 (9)°] and perpendicular to the mean plane through the five-membered ring [dihedral angles of 89.98 (10) and 89.04 (10)°]. The crystal structure is stabilized by inter­molecular C—H⋯O hydrogen-bonding inter­actions

Investigation of transpiration cooling with local thermal non-equilibrium model: Effects of different thermal boundary conditions at the porous-fluid interface

In this study, the main stream coupled with a porous medium with local thermal non-equilibrium assumption is analyzed. The flow inside the porous material is modelled using the Darcy–Brinkman–Forchheimer equation and the incompressible Navier-Stokes equations are solved for the main stream. Several couple conditions between the main flow temperature and the temperatures of the solid matrix and coolant flow at the fluid/porous interface is calculated. The results show that the Model C assumes the main flow temperature equals the solid phase temperature and the main flow heat flux is all imposed on the solid phase gives the most reasonable answer

Draft Genome Sequence of Streptomyces sp. Strain CT34, Isolated from a Ghanaian Soil Sample

Copyright © 2015 Zhai et al. This work was supported by the China “973” program (2012CB721001), the “863” Program (2012AA092201), the National Natural Science Foundation of China (31170467), and the EU FP7 project PharmaSea (312184). K.K., M.J., and H.D. thank the Royal Society–Leverhulme Trust Africa for the financial support (award AA090088) that enabled the sampling of sediments and subsequent isolation of this unique Ghanaian strain.Non peer reviewedPublisher PD

Structural mechanism for bacterial oxidation of oceanic trimethylamine into trimethylamine N -oxide

Trimethylamine (TMA) and trimethylamine N-oxide (TMAO) are widespread in the ocean and are important nitrogen source for bacteria. TMA monooxygenase (Tmm), a bacterial flavin-containing monooxygenase (FMO), is found widespread in marine bacteria and is responsible for converting TMA to TMAO. However, the molecular mechanism of TMA oxygenation by Tmm has not been explained. Here, we determined the crystal structures of two reaction intermediates of a marine bacterial Tmm (RnTmm) and elucidated the catalytic mechanism of TMA oxidation by RnTmm. The catalytic process of Tmm consists of a reductive half-reaction and an oxidative half-reaction. In the reductive half-reaction, FAD is reduced and a C4a-hydroperoxyflavin intermediate forms. In the oxidative half-reaction, this intermediate attracts TMA through electronic interactions. After TMA binding, NADP+ bends and interacts with D317, shutting off the entrance to create a protected micro-environment for catalysis and exposing C4a-hydroperoxyflavin to TMA for oxidation. Sequence analysis suggests that the proposed catalytic mechanism is common for bacterial Tmms. These findings reveal the catalytic process of TMA oxidation by marine bacterial Tmm and first show that NADP+ undergoes a conformational change in the oxidative half-reaction of FMOs

Lnc RNA HOTAIR functions as a competing endogenous RNA to regulate HER2 expression by sponging miR-331-3p in gastric cancer

BACKGROUND: Accumulating evidence indicates that the long non-coding RNA HOTAIR plays a critical role in cancer progression and metastasis. However, the overall biological role and clinical significance of HOTAIR in gastric carcinogenesis remains largely unknown. METHODS: HOTAIR expression was measured in 78 paired cancerous and noncancerous tissue samples by real-time PCR. The effects of HOTAIR on gastric cancer cells were studied by overexpression and RNA interference approaches in vitro and in vivo. Insights of the mechanism of competitive endogenous RNAs (ceRNAs) were gained from bioinformatic analysis, luciferase assays and RNA binding protein immunoprecipitation (RIP). The positive HOTAIR/HER2 interaction was identified and verified by immunohistochemistry assay and bivariate correlation analysis. RESULTS: HOTAIR upregulation was associated with larger tumor size, advanced pathological stage and extensive metastasis, and also correlated with shorter overall survival of gastric cancer patients. Furthermore, HOTAIR overexpression promoted the proliferation, migration and invasion of gastric carcinoma cells, while HOTAIR depletion inhibited both cell invasion and cell viability, and induced growth arrest in vitro and in vivo. In particular, HOTAIR may act as a ceRNA, effectively becoming a sink for miR-331-3p, thereby modulating the derepression of HER2 and imposing an additional level of post-transcriptional regulation. Finally, the positive HOTAIR/HER2 correlation was significantly associated with advanced gastric cancers. CONCLUSIONS: HOTAIR overexpression represents a biomarker of poor prognosis in gastric cancer, and may confer malignant phenotype to tumor cells. The ceRNA regulatory network involving HOTAIR and the positive interaction between HOTAIR and HER2 may contribute to a better understanding of gastric cancer pathogenesis and facilitate the development of lncRNA-directed diagnostics and therapeutics against this disease