miR-1827抑制甲状腺乳头状癌细胞增殖、侵袭转移及对c-Myc基因表达的影响

目的:探讨微小RNA 1827(miR-1827)对甲状腺乳头状癌细胞增殖、侵袭转移及对c-Myc基因表达的影响。方法:采用实时荧光定量聚合酶链反应(qPCR)检测miR-1827在TPC-1和Nthy-ori 3-1细胞中的表达,分别用CCK-8、细胞侵袭和蛋白质印迹法(Western blot)检测过表达及干扰miR-1827对TPC-1细胞增殖、侵袭和上皮间质转化(EMT)的影响。采用TargetScan和双荧光素酶报告基因实验分析miR-1827与c-Myc之间的作用靶点,通过qPCR和Western blot检测miR-1827和c-Myc之间的调控关系。通过Western blot分析miR-1827对TPC-1细胞中Akt-mTOR通路的影响。雷帕霉素抑制Akt-mTOR通路后,检测miR-1827对甲状腺乳头状癌细胞增殖、侵袭转移以及对c-Myc基因表达的影响。结果:TPC-1细胞中miR-1827表达水平明显低于Nthy-ori 3-1细胞(P<0.01),过表达miR-1827能够抑制TPC-1细胞的增殖和侵袭(P<0.05),E-cadherin蛋白表达量明显上升(P<0.01),N-cadherin蛋白表达量明显下降(P<0.01)。下调miR-1827能够促进TPC-1细胞的增殖、侵袭和EMT(P<0.05)。c-Myc是miR-1827的直接作用靶点,过表达miR-1827抑制c-Myc表达(P<0.01),敲低miR-1827促进c-Myc表达(P<0.01)。miR-1827激活了TPC-1细胞中Akt-mTOR信号通路,雷帕霉素作用于细胞后,明显降低了miR-1827对TPC-1细胞增殖、侵袭和EMT以及c-Myc表达的抑制作用(P<0.05)。结论:miR-1827通过Akt-mTOR途径抑制了甲状腺乳头状癌细胞的增殖、侵袭转移以及c-Myc的表达。

Three-source partitioning of soil respiration by ^(13)C natural abundance and its variation with soil depth in a plantation

Partitioning soil respiration into three components is vital to identify CO_2 sink or source and can help us better understand soil carbon dynamics. However, knowledge about the influences of soil depth and the priming effect on soil respiration components under field has been limited. Three components of soil respiration(root respiration, rhizomicrobial respiration and basal respiration) in a plantation in the hilly area of the North China were separated by the 13 C natural abundance method. The results showed that the average proportions of rhizomicrobial respiration, root respiration and basal respiration at the 25–65 cm depths were about 14, 23 and 63 %, respectively. Three components of soil respiration varied with soil depth, and root respiration was the main component of soil respiration in deeper soil. The priming effect was obvious for the deep soil respiration, especially at the 40–50 cm depth. Thus, depth and priming effect should be taken into account to increase the accuracy of estimations of soil carbon flux.

Computer-aided identification of protein targets of four polyphenols in Alzheimer's disease(AD)and validation in a mouse AD model

Natural polyphenols are a large class of phytochemicals with neuroprotective effects. Four polyphenolic compounds: hesperidin, icariin, dihydromyricetin and baicalin were selected to evaluate their effects on Alzheimer's disease(AD). We analyzed by an inverse docking procedure(INVDOCK) the potential protein targets of these polyphenols within the KEGG AD pathway. Consequently, their therapeutic effects were evaluated and compared in a transgenic APP/PS1 mouse model of AD. These polyphenols were docked to several targets, including APP, BACE,PSEN, IDE, CASP, calpain and TNF-a, suggesting potential in vivo activities. Five month old transgenic mice were treated with these polyphenols. Icariin and hesperidin restored behavioral deficits and ameliorated Aβ deposits in both the cortex and hippocampus while baicalin and dihydromyricetin showed no substantial effects. Our findings suggest that hesperidin and icariin could be considered potential therapeutic candidates of human AD.

Separating component parts of soil respiration under Robinia pseudoacacia plantation in the Taihang Mountains,China

Partitioning the respiratory components of soil surface CO_2 efflux is important in understanding carbon turnover and in identifying the soil carbon sink/source function in response to land-use change. The sensitivities of soil respiration components on changing climate patterns are currently not fully understood. We used trench and isotopic methods to separate total soil respiration into autotrophic(RA) and heterotrophic components(R_H). This study was undertaken on a Robinia pseudoacacia L. plantation in the southern Taihang Mountains, China. The fractionation of soil^(13)CO_2 was analyzed by comparing the δ^(13) C of soil CO_2 extracted from buried steel tubes with results from Gas Vapor Probe Kits at a depth of 50 cm at the preliminary test(2.03%). The results showed that the contribution of autotrophic respiration(f R_A) increased with increasing soil depth.The contribution of heterotrophic respiration(f R_H) declined with increasing soil depth. The contribution of autotrophic respiration was similar whether estimated by the trench method(f RA, 23.50%) or by the isotopic method in which a difference in value of^(13) C between soil and plant prevailed in the natural state(R_C, 21.03%). The experimental error produced by the trench method was insignificant as compared with that produced by the isotopic method, providing a technical basis for further investigations.

Photosynthetic stimulation of saplings by the interaction of CO2 and water stress

Climate change necessitates research into interactions between elevated carbon dioxide(CO2)concentrations and drought on plant photosynthetic physiology.This study describes the physiological properties of Platycladus orientalis(Chinese thuja)and Quercus variabilis(Chinese cork oak)saplings cultivated through orthogonal treatments of four CO2 concentrations combined with five soil volumetric water contents(SWC).It highlights the differences between the interactive effects from the treatments.Water stress had little effect on photosynthetic traits until the soil volumetric water contents exceeded 70–80 or 100%.Similar variations in carbon-13 isotope abundance(δ^13C)of water soluble compounds(δ^13CWSC)extracted from leaves of two species have been observed.Whether soil volumetric water contents exceeded or fell below the water threshold values(70–80%of field capacity for P.orientalis and 100%of field capacity for Q.variabilis),instantaneous water use efficiency decreased.Elevated carbon dioxide could increase iWUE and enhance drought tolerance,depending on stimulating net photosynthetic rates and declining stomatal conductance and transpiration rates.Augmenting either drought,excess water,or ambient carbon dioxide could alleviate the physiological inhibition caused by the stresses described above.

Seasonal dynamics of foliar δ^(13)C and nutrient concentration of Chinese chastetree and spine jujube in foothill rock outcrop habitat of the southern Taihang Mountains, Central China

In this study, in situ investigation was conducted on Chinese chastetree(Vitex negundo var. heterophylla)and spine jujube(Ziziphus jujuba var. spinosa) during early, developed, and closing succession stages. Monthly data were recorded for foliar δ^(13)C values and foliar N, P,and K concentrations from May to October. Foliar δ^(13)C values declined with time and differences by succession stage varied by species. Older spine jujube displayed higher foliar N concentration while foliar P concentration was inversely related with N. Chinese chastetree had lower foliar K concentration than spine jujube. Foliar C/N ratio declined during the dry season and increased in the wet season. Foliar N/P ratio increased during the dry season and declined to its initial level until October, when it increased again. Foliar δ^(13)C value was positively correlated with foliar N concentration. Foliar P and K concentrations were positively correlated to each other. In conclusion, the two shrubs had contrasting strategies of water use efficiency during their succession, but water use efficiency of both species was promoted by N availability and limited by P availability.

Large-Scale Forward Genetic Screening Analysis of Development of Hematopoiesis in Zebrafish

Zebrafish 是为造血作用的调查的一个有力的模型。以便与造血的缺点孤立新奇异种， zebrafish 屏蔽的大规模 mutagenesis 被执行。由获得特定的造血的标记， 52 异种基于特定的 phenotypic 特点被鉴别然后分类类型进四。每异种代表了调整造血作用的相关方面的基因的一个通常认为的变化，包括早巨噬细胞开发，早 granulopoiesis，胚胎的 myelopoiesis，和权威的红血球生成 / 淋巴细胞增殖。我们的方法应该为在 zebrafish 的基因屏蔽的另外的类型是适用的。另外，我们识别了的异种的进一步的学习可以帮助揭开造血作用的分子的基础。

Anticarin-β shows a promising antiosteosarcoma effect by specifically inhibiting CCT4 to impair proteostasis

Unlike healthy, non-transformed cells, the proteostasis network of cancer cells is taxed to produce proteins involved in tumor development. Cancer cells have a higher dependency on molecular chaperones to maintain proteostasis. The chaperonin T-complex protein ring complex(TRiC) contains eight paralogous subunits(CCT1-8), and assists the folding of as many as 10% of cytosolic proteome.TRiC is essential for the progression of some cancers, but the roles of TRiC subunits in osteosarcoma remain to be explored. Here, we show that CCT4/TRiC is significantly correlated in human osteosarcoma,and plays a critical role in osteosarcoma cell survival. We identify a compound anticarin-β that can specifically bind to and inhibit CCT4. Anticarin-β shows higher selectivity in cancer cells than in normal cells. Mechanistically, anticarin-β potently impedes CCT4-mediated STAT3 maturation. Anticarin-β displays remarkable antitumor efficacy in orthotopic and patient-derived xenograft models of osteosarcoma.Collectively, our data uncover a key role of CCT4 in osteosarcoma, and propose a promising treatment strategy for osteosarcoma by disrupting CCT4 and proteostasis.

Zebrafish Cdh5 negatively regulates mobilization of aorta-gonad-mesonephros-derived hematopoietic stem cells

Establishment of a hematopoietic stem cell(HSC)pool depends on the appropriate formation,maturation and mobilization of HSCs in vertebrates.In mice,the aorta-gonad-mesonephros(AGM)is a prominent site for the formation of definitive HSCs from endothelial cells,although the placenta and yolk sac also give rise to HSCs(Mikkola and Orkin,2006;Chen et al.,2009).After formation,AGM-derived HSCs migrate to the fetal liver(FL),and