Monitoring the Invasion of Spartina alterniflora from 1993 to 2014 with Landsat TM and SPOT 6 Satellite Data in Yueqing Bay,China

The exotic plant Spartina alterniflora was introduced to Yueqing Bay more than 20 years ago for tidal land reclamation and as a defense against typhoons, but it has rapidly expanded and caused enormous ecological consequences. Mapping the spread and distribution of S. alterniflora is the first step toward understanding the factors that determine the population expansion patterns. Remote sensing is a promising tool to monitor the expansion of S. alterniflora. Twelve Landsat TM images and Support Vector Machine (SVM) were used to delineate the invasion of S. alterniflora from 1993 to 2009, and SPOT 6 images and Object-Based Image Analysis (OBIA) were used to map the distribution of S. alterniflora in 2014. In situ data and Unmanned Aerial Vehicle (UAV) images were used as supplementary data. S. alterniflora spread rapidly in Yueqing Bay over the past 21 years. Between 1993 and 2009, the area of S. alterniflora increased by 608 times (from 4 to 2432 ha). The rapid expansion of S. alterniflora covered almost all of the bare mudflats around the mangrove forests and the cultivated mudflats. However, from 2009 to 2014, the rate of expansion of S. alterniflora began to slow down in Yueqing Bay, and the total area of S. alterniflora in Yantian decreased by 275 ha. These phenomena can be explained by the landscape changes and ecological niches. Through the expansion of S. alterniflora, it was found that the ecological significance and environmental impact of S. alterniflora was different in different regions in Yueqing Bay. The conservation plans for Yueqing Bay should consider both the positive and negative effects of S. alterniflora, and the governmental policy should be based on the different circumstances of the regions.     

Synthesis and biological activities evaluation of sanjuanolide and its analogues

Sanjuanolide, psorachalcone A and its seven new analogues were synthesized via a combinatorial strategy by aldol reaction. In order to investigate the effect between electron density in π-conjugated systems and biological activities, several electron-withdrawing and electron-donating groups were introduced at C-4 and the phenolic hydroxyl groups of sanjuanolide. The two natural products and its seven new analogues were investigated for their inhibitory effects against five cancer cell lines. Moreover, the hydroxyisoprenyl group may be important to maintain the biological activities of sanjuanolide.     

3-甾酮-9α-羟基化酶基因在分枝杆菌中的异源表达与9α-羟基雄烯二酮的制备

9α-羟基雄烯二酮(9-OH-AD)是制备甾体类药物的重要中间产物。3-甾酮-9α-羟基化酶(KSH)能够转化雄烯二酮(AD)产生9α-羟基雄烯二酮(9-OH-AD),该酶由Ksh A和Ksh B两个亚基构成。为获得高效积累9-OH-AD的重组菌株,本研究选择耻垢分枝杆菌Mycobacterium smegmatis mc2155和戈登氏菌Gordonia neofelifaecis NRRL B-59395,对其在胆固醇为唯一碳源条件下表达明显上调的ksh A和ksh B候选基因进行克隆,插入到分枝杆菌表达载体p NIT中,构建共表达质粒,并将它们导入分枝杆菌Mycobacterium sp.NRRL B-3805中,获得重组菌株。利用重组菌株分别对植物甾醇、胆固醇和谷甾醇进行生物转化,分离纯化转化产物,采用光谱学方法鉴定其化学结构,确定该转化产物为9α-羟基雄烯二酮,说明分枝杆菌Mycobacterium sp.NRRL B-3805由积累雄烯二酮变为积累9α-羟基雄烯二酮(9-OH-AD),进而证明导入的候选基因ksh A和ksh B确实为有功能的基因。生物转化实验表明,与胆固醇、谷甾醇相比,植物甾醇作为底物更易于转化;而用来源于耻垢分枝杆菌的ksh A、ksh B构建的重组菌转化率更高,可达90%,具有较高的应用价值。本研究通过对KSH编码基因的异源表达,成功地进行了分枝杆菌生物转化特性的改造,为探索各种甾体药物中间体的工业生产奠定了基础。     

Micheliolide Derivative DMAMCL Inhibits Glioma Cell Growth In Vitro and In Vivo

BackgroundThere is no highly effective chemotherapy for malignant gliomas to date. We found that dimethylaminomicheliolide (DMAMCL), a selective inhibitor of acute myeloid leukemia (AML) stem/progenitor cells, inhibited the growth of glioma cells.MethodsThe distribution of DMAMCL in brain was analyzed by an ultraperformance liquid chromatography-mass spectrometry (UPLC-MS/MS) system. The anti-tumor evaluations of DMAMCL in vitro were performed by MTT, FACS and RT-PCR. In vivo, the mixture of C6 cells and matrigel was injected into caudatum, and the anti-tumor activity of DMAMCL was evaluated by tumor growth and rat survival. The toxicity of DMAMCL was evaluated by body weight, daily food intake, hematological or serum biochemical analyses, and histological appearance of tissues.ResultsThe IC₅₀ values of DMAMCL against the C6 and U-87MG cell lines in vitro were 27.18 ± 1.89 μM and 20.58 ± 1.61 μM, respectively. DAMMCL down-regulated the anti-apoptosis gene Bcl-2 and increased apoptosis in C6 and U-87MG cells in a dose-dependent manner. In a C6 rat tumor model, daily administration of DMAMCL for 21 days reduced the burden of C6 tumors by 60% to 88% compared to controls, and more than doubled the mean lifespan of tumor-bearing rats. Distribution analysis showed that the DMAMCL concentration was higher in the brain than in plasma. Evaluations for toxicity revealed that oral administration of DMAMCL at 200 or 300 mg/kg once a day for 21 days did not result in toxicity.ConclusionsThese results suggest that DMAMCL is highly promising for the treatment of glioma.     

A new strategy of transforming an ACQ compound into an AIE theranostic system for bacterial imaging and photodynamic antibacterial therapy

An organic chemical with fluorescence quenching properties [aggregation-caused quenching (ACQ)] may often be transformed by adding functional groups that cause aggregation-induced emission (AIE) to its molecular scaffold. Such structural change techniques, however, sometimes require challenging chemical reactions. SF136 is a type of chalcone, and it is an typical ACQ organic compound. In this study, cationic surfactants like hexadecyltrimethylammonium bromide (CTAB) and polyethyleneimine (PEI) were used to convert the ACQ compound SF136 into an AIE compound without adding any AIE structure units. In comparison to SF136, the SF136-CTAB NPS system not only demonstrated improved bacterial fluorescence imaging capabilities, but also increased photodynamic antibacterial activity, which is connected to its improved targeting and reactive oxygen species (ROS) production abilities. It is a promising theranostic substance against bacteria owing to these enhanced qualities. Other ACQ fluorescent compounds may also benefit from using this approach, broadening the scope of their potential applications.