我国西南元江大理茶的挥发性成分及其抗氧化活性

大理茶(Camellia taliensis)为山茶科山茶属茶组植物,主要分布于云南横断山脉澜沧江至伊洛瓦底江流域,即从云南的西部及西南部至缅甸北部.在其分布区,大理茶亦被称为野生大茶树,常用于加工制作茶叶.采用水蒸气蒸馏法、GC及GC/MS联用技术,首次对大理茶的鲜幼叶和鲜幼叶及老叶分别制成的绿茶中的挥发性成分进行提取和分析,共鉴定出91个化合物.研究结果表明,大理茶鲜幼叶的主要香气成分为棕榈酸(30.52％),亚油酸(19.82％),植醇(8.75％)和亚麻酸乙酯(2.54％)等有机酸及其酯和二萜类,而制成绿茶后,其主要香气成分则为芳樟醇(28.43％),脱氢芳樟醇(1.13％),α-松油醇(11.68％),橙花醇(4.92％)和香叶醇(12.34％)等单萜醇类成分.从大理茶鲜叶到由其制成的绿茶,香气成分发生了较大变化,形成了28种原鲜叶中未检测到的香气成分,其中,(Z,Z,Z)-9,12,15-十八烷三烯-1-醇的含量分别达到1.21％(幼叶绿茶)和11.2％(老叶绿茶),是大理茶制作的绿茶的特征香气成分.DPPH和ABTS+自由基清除实验结果显示大理茶鲜叶及其制成的绿茶的挥发性成分均具有一定的抗氧化活性,但均弱于茶多酚的抗氧化活性.     

Sonic Hedgehog pathway is essential for neuroblastoma cell proliferation and tumor growth

Products of prolidase [E.C. 3.4.13.9] activity, proline or hydroxyproline, contribute to up-regulation of hypoxia-inducible factor-1α (HIF-1α). Prolidase activity is regulated by β(1)-integrin signaling. We studied the effects of echistatin (a well-known disintegrin) and thrombin (a serine protease capable of activation of integrin α(2)β(1) receptor) on prolidase activity and expressions of prolidase, α(2)β(1)-integrin receptor, focal adhesion kinase (FAK), MAP-kinases (ERK(1) and ERK(2)), and nuclear HIF-1α in human colon adenocarcinoma (DLD-1) cells. It has been found that treatment of the cells with thrombin contributes to decrease in the expression of prolidase and simultaneously increase in its phosphorylation, resulting in maintenance of the enzyme activity. The phenomenon was accompanied by thrombin-dependent recovery of depressed autophosphorylation of FAK (pY(397)) under the effect of FAK inhibitor (1,2,4,5-benzenetetramine tetrahydrochloride). Although integrin α(2)β(1) receptor expression was not affected by thrombin, the signaling induced by thrombin up-regulated nuclear HIF-1α expression. It was accompanied by increase in the expression of MAP kinases, ERK1 and ERK2. It suggests that integrin-dependent signaling through p-FAK is up-regulated in DLD-1 cells and it may represent potential target for anti-cancer therapy.     

The comparition of biological characteristics and multilineage differentiation of bone marrow and adipose derived Mesenchymal stem cells

We compared the two sources of adipose and bone marrow-derived mesenchymal stem cells (BMSCs and AMSCs ) in multiple differentiation capacity and biological characteristics to provide a theoretical basis for stem cells transplantation. We isolated bone marrow- and adipose-derived mesenchymal stem cells and compared their phenotype,cell doubling time, the secretion of factors and their ability of multi-differentiation. We also compared their differences in T lymphocyte activation, proliferation and suppression. BMSCs and AMSCs were similar in cell phenotype and the differences existed only in the expression of CD106. On the proliferation rate, AMSCs were faster than BMSCs (doubling time 28 vs. 39?h). In addition, both of these two sources of cells were able to differentiate into bone, fat and cartilage that proved their stem cells properties and the number of stem cell progenitors (CFU-F) from adipose tissue were 10 times larger than those from bone marrow. But AMSCs showed a diminished capacity for suppressing T lymphocyte proliferation and activation compared to BMSCs. Cell origin and abundance were decisive factors in stem cells applications and, in the same volume, with the same premise of AMSCs and BMSCs, adipose tissue is a more promising source of stem cells.     

Isolation and Identification of Endophytic Fungi in Roots of Nine <Emphasis Type="Italic">Holcoglossum</Emphasis> Plants (Orchidaceae) Collected from Yunnan,Guangxi, and Hainan Provinces of China

Holcoglossum is one of the smaller genera of Orchidaceae, mainly distributed in southwest China. Some members of this genus as well as H. rupestre and H. flavescens are endemic and rare Chinese orchids. As far as we know, little work has been done concerning the relationships between the Holcoglossum plants and endophytic microorganisms. In this study, 46 culturable fungal endophytes were isolated and identified from roots of nine Holcoglossum plants collected from Yunnan, Guangxi, and Hainan provinces of China based on molecular techniques. The results showed that all strains belonged to four classes, i.e., Sordariomycetes (41.30%), Dothideomycetes (36.96%), Agaricomycetes (17.39%), Leotiomycetes (4.35%). Thirty-six strains were identified at the genus level, including Alternaria, Cladosporium, Clonostachys, Colletotrichum, Cosmospora, Cryptosporiopsis, Cylindrocarpon, Didymella, Epulorhiza (Anamorphic Tulasnella), Fusarium, Myrmecridium, Leptosphaeria, Paraconiothyrium, Phomopsis, Pyrenochaeta, and Stephanonectria. Fusarium and Epulorhiza (Anamorphic Tulasnella) were the dominant fungal endophytes. Some orchids mycorrhizal fungi as well as Tulasnella calospora and Epulorhiza sp. were found in roots. This is the first report concerning endophytic fungi from Holcoglossum plants (Orchidaceae), suggesting that endophytic fungi in Holcoglossum plants are very abundant.     

Effects of castration on aggression and levels of serum sex hormones and their central receptors in mandarin voles (Microtus mandarinus)

Aggression in socially monogamous mandarin vole (Microtus mandarinus) was observed after castration. Levels of serum sex hormones and their central receptors were also measured using enzyme-linked immunosorbent assay and immunohistochemistry methods. The data indicate that adult males showed higher levels of aggression after castration. However, castration significantly reduced levels of serum testosterone, and the number of androgen receptor immunoreactive neurons in the anterior hypothalamus, bed nucleus of the stria terminalis, medial amygdaloid nucleus (P < 0.01) and lateral septal nucleus (P < 0.05). In addition, levels of estrogen receptor β in the anterior hypothalamus and medial amygdaloid nucleus (P < 0.05), bed nucleus of the stria terminalis and lateral septal nucleus (P < 0.01) declined to varying degrees at weekly intervals. In contrast, serum 17β-estradiol concentrations were up-regulated by castration and castration did not change levels of estrogen receptor α in the medial amygdaloid nucleus and lateral septal nucleus, but increased it in the anterior hypothalamus 3 weeks after castration (P < 0.05). We suggest that higher levels of aggression induced by castration may be independent of serum testosterone and androgen receptors, and may be associated with high serum 17β-estradiol concentrations, stable estrogen receptor α immunoreactive neurons in some brain regions and the relative ratio of the two estrogen receptors.     

Clinical and biological significance of Cdk10 in hepatocellular carcinoma

Cyclin-dependent kinase 10 (Cdk10) is a Cdc2-related kinase and plays an essential role in the progression from the G2 to M phase of the cell cycle. However, relative little is known about its expression pattern, clinical relevance, and biological function in hepatocellular carcinoma (HCC). In the present study, we investigated the mRNA and protein expression levels of Cdk10 in 127 pairs of HCC samples and adjacent nontumorous liver tissues and evaluated its clinical significance. Additionally, we assessed the effects of restoration of Cdk10 on cell proliferation and drug sensitivity in HCC cells. We showed that the Cdk10 mRNA and protein expression was markedly decreased in HCC samples compared to adjacent nontumorous liver tissues. Quantitative real-time polymerase chain reaction and immunohistochemical studies revealed that reduced Cdk10 expression was significantly associated with alpha-fetoprotein levels, tumor size, and tumor stage. Ectopic expression of Cdk10 reduced HCC cell proliferation, blocked the cell cycle at the G0-G1 phase, as well as inhibited cell migration and anchorage-independent growth. Additionally, Cdk10 overexpression enhanced the chemosensitivity of HCC cells to cisplatin and epidoxorubicin, two chemotherapeutic agents commonly used in HCC. These data collectively demonstrate that reduced Cdk10 expression is closely linked to HCC development and progression. Restoration of its expression may have therapeutic benefits in treating this malignancy.     

Nanovesicle-based bioelectronic nose platform mimicking human olfactory signal transduction

We developed a nanovesicle-based bioelectronic nose (NBN) that could recognize a specific odorant and mimic the receptor-mediated signal transmission of human olfactory systems. To build an NBN, we combined a single-walled carbon nanotube-based field effect transistor with cell-derived nanovesicles containing human olfactory receptors and calcium ion signal pathways. Importantly, the NBN took advantages of cell signal pathways for sensing signal amplification, enabling ≈ 100 times better sensitivity than that of previous bioelectronic noses based on only olfactory receptor protein and carbon nanotube transistors. The NBN sensors exhibited a human-like selectivity with single-carbon-atomic resolution and a high sensitivity of 1 fM detection limit. Moreover, this sensor platform could mimic a receptor-meditated cellular signal transmission in live cells. This sensor platform can be utilized for the study of molecular recognition and biological processes occurring at cell membranes and also for various practical applications such as food screening and medical diagnostics.     

SAR and in vivo evaluation of 4-aryl-2-aminoalkylpyrimidines as potent and selective Janus kinase 2 (JAK2) inhibitors

We report the discovery of a series of 4-aryl-2-aminoalkylpyrimidine derivatives as potent and selective JAK2 inhibitors. High throughput screening of our in-house compound library led to the identification of hit 1, from which optimization resulted in the discovery of highly potent and selective JAK2 inhibitors. Advanced lead 10d demonstrated a significant dose-dependent pharmacodynamic and antitumor effect in a mouse xenograft model. Based upon the desirable profile of 10d (XL019) it was advanced into clinical trials.