Three new taxanes with the 10-alkoxy group from the heartwood of Taxus cuspidata

Three novel taxanes with the 10-alkoxy group were isolated from heartwood of Taxus cuspidata. The structures were identified as 2alpha,14beta-diacetoxy-10beta-ethoxytaxa-11,4(20)-dien-5alpha-ol (1), 2alpha,14beta-diacetoxy-10beta-methoxytaxa-11,4(20)-dien-5alpha-ol (2), and 2alpha-acetoxy-10beta-ethoxytaxa-11,4(20)-diene-5alpha,14beta-diol (3) on the basis of spectroscopic analysis. These are the first taxanes with an alkoxy moiety on the skeleton.     

土壤水分含量的理论分析及预测模型

本文应用物理学中的电介质和电磁理论,分析和研究土壤的组成成分,得到了反映土壤水分含量的理论表达式,并在自行研制的测试仪器上,对相关变量进行测量,由此建立了土壤水分含量的预测模型,统计检验和国代结果显示了理论模型和预测模型的合理性．     

siRNA在治疗学中的应用

小干扰RNA（small interfering RNA,siRNA）是外源性双链RNA（double strand RNA,dsRNA）的加工产物,在细胞内能介导RNA干扰（RNA interference,RNAi）效应,识别特异性mRNA,沉默同源基因表达。其特异性和高效性显示出很高的实用价值,siRNA已成为许多疾病潜在的治疗手段。对于siRNA的应用,尽管还需要在减少非特异反应,发掘高效递药载体,应对新的基因变异等方面进行深入研究,但其可望在抗病毒、神经系统疾病和肿瘤治疗等许多领域发挥治疗作用。     

分子标记在油菜杂种优势利用中的研究进展

杂种优势是一种普遍存在的生物学现象,是提高作物产量的重要途径,因而受到越来越广泛的重视。分子标记是近年兴起的一种新型的生物技术,国内外已利用RFLP、RAPD、AFLP、SSR、ISSR和SRAP等多种分子标记技术对油菜的杂种优势进行了广泛的研究,取得了很多有价值的研究成果。本文综述了分子标记在油菜授粉控制系统中关键基因标记、亲本遗传多样性分析、杂种优势群划分、杂种纯度鉴定和杂种优势预测中的研究进展。通过对不同作物间的比较,探讨了分子标记在油菜杂种优势利用中的研究深度,并对分子标记在油菜杂种优势预测中应注意的问题进行了讨论。     

Inhibition of circular RNA CDR1as increases chemosensitivity of 5‐FU‐resistant BC cells through up‐regulating miR‐7

This study aims to explore the mechanism of Circular RNA CDR1as implicating in regulating 5‐fluorouracil (5‐FU) chemosensitivity in breast cancer (BC) by competitively inhibiting miR‐7 to regulate CCNE1. Expressions of CDR1as and miR‐7 in 5‐FU‐resistant BC cells were determined by RT‐PCR. CCK‐8, colony formation assay and flow cytometry were applied to measure half maximal inhibitory concentration (IC50), 5‐Fu chemosensitivity and cell apoptosis. Western blot was used to detect the expressions of apoptosis‐related factors. CDR1as was elevated while miR‐7 was inhibited in 5‐FU‐resistant BC cells. Cells transfected with si‐CDR1as or miR‐7 mimic had decreased IC50 and colony formation rate, increased expressions of Bax/Bcl2 and cleaved‐Caspase‐3/Caspase‐3, indicating inhibition of CDR1as and overexpression of miR‐7 enhances the chemosensitity of 5‐FU‐resistant BC cells. Targetscan software indicates a binding site of CDR1as and miR‐7 and that CCNE1 is a target gene of miR‐7. miR‐7 can gather CDR1as in BC cells and can inhibit CCNE1. In comparison to si‐CDR1as group, CCNE1 was increased and chemosensitivity to 5‐Fu was suppressed in si‐CDR1as + miR‐7 inhibitor group. When compared with miR‐7 mimic group, CDR1as + miR‐7 mimic group had increased CCNE1 and decreased chemosensitivity to 5‐Fu. Nude mouse model of BC demonstrated that the growth of xenotransplanted tumour in si‐CDR1as + miR‐7 inhibitor group was faster than that in si‐CDR1as group. The tumour growth in CDR1as + miR‐7 mimic group was faster than that in miR‐7 mimic group. CDR1as may regulate chemosensitivity of 5‐FU‐resistant BC cells by inhibiting miR‐7 to regulate CCNE1.     

Genetic mutation analysis at early stages of cell line development using next generation sequencing

A central goal for most biopharmaceutical companies is to reduce the development timeline to reach clinical proof of concept. This objective requires the development of tools that ensure the quality of biotherapeutic material destined for the clinic. Recent advances in high throughput protein analytics provide confidence in our ability to assess productivity and product quality attributes at early stages of cell line development. However, one quality attribute has, until recently, been absent from the standard battery of analytical tests facilitating informed choices early in cell line selection: genetic sequence confirmation. Techniques historically used for mutation analysis, such as detailed mass spectrometry, have limitations on the sample number and turnaround times making it less attractive at early stages. Thus, we explored the utility of Next‐Generation Sequencing (NGS) as a solution to address these limitations. Amplicon sequencing is one such NGS technique that is robust, rapid, sensitive, and amenable to multiplexing, all of which are essential attributes for our purposes. Here we report a NGS method based upon amplicon sequencing that has been successfully incorporated into our cell line development workflow alongside other high‐throughput protein analytical assays. The NGS method has demonstrated its value by identifying at least one Chinese hamster ovary (CHO) clone expressing a variant form of the biotherapeutic in each of the four clinical programs in which it has been utilized. We believe this sequence confirmation method is essential to safely accelerating the time to clinical proof of concept of biotherapeutics, and guard against delays related to sequence mutations. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:813–817, 2016     

沿水分梯度草原群落NPP动态及对气候变化响应的模拟分析

 水分条件不仅影响半干旱区群落的组成, 而且在一定程度上决定了群落的功能。处于不同水分条件生境下群落的优势物种在水分利用和同化物利用效率方面的功能特征会存在差异, 这些差异将导致群落对于气候变化产生不同的响应, 进而影响到景观和区域尺度上对于全球变化下碳动态和格局的分析。该文选取了锡林河流域典型草原区沿水分梯度的4个代表群落, 在野外实验测定并结合长期定位研究成果基础上, 利用BIOME-BGC模型对代表群落的长期净初级生产力(Net primary productivity,NPP)动态进行了模拟和模型验证。 通过分析该地区1953～2005年气候变化趋势, 推测了未来可能的气候变化情景, 进而模拟了气候变化下4个群落长期NPP动态的响应。结果表明,当前气候条件下, 羊草(Leymus chinensis)群落NPP平均值为197.76 gC·m^-2 (SE=7.11), 大针茅(Stipa grandis)群落NPP平均值为198.95 gC·m^-2 (SE=6.41), 贝加尔针茅(Stipa baicalensis)群落NPP平均值为210.41 gC·m^-2(SE=7.87), 克氏针茅(Stipa krylovii)群落NPP平均值为144.92 gC·m^{- 2} (SE=4.64), 4个群落NPP平均值为188.01 gC·m^-2 (SE=3.72); 气候变化情景下, 温度增加下(P0T1),NPP平均下降14.2%,降水增加下(P1T0), NPP平均增加13.2%,温度与降水都增加情景下(P1T1), NPP平均下降2 .7%, 但由于生境水分条件差别和优势物种功能特征差异, 4个群落表现出了增减幅度不同的趋势。对气候因子的敏感性分析及回归分析表明, 降水是该地区NPP最主要的决定因子, 而温度决定作用相对较小,主要通过影响植物的呼吸和水分蒸散等过程影响NPP。在最有可能代表未来气候 变化的温度增加的两种情景下(P0T1、P1T1), NPP均呈下降趋势。群落NPP对气候变化的响应趋势与水分胁迫系数(Water stress index, WSI)、碳胁迫系数(Carbon stress index, CSI)变化密切相关。克氏针茅群落由于所处生境水分条件差,WSI高,对降水的依赖程度最大;贝加尔针茅群落一方面处于较好的水分生境,具有较小的WSI,另一方面,由于具有高碳氮比,维持呼吸消耗的光合产物比例低,CSI远低于其它3个群落, 未来气候变化下, NPP较其它3个群落仍较高。     

Development of Fatal Intestinal Inflammation in MyD88 Deficient Mice Co-infected with Helminth and Bacterial Enteropathogens

Infections with intestinal helminth and bacterial pathogens, such as enteropathogenic Escherichia coli, continue to be a major global health threat for children. To determine whether and how an intestinal helminth parasite, Heligomosomoides polygyrus, might impact the TLR signaling pathway during the response to a bacterial enteropathogen, MyD88 knockout and wild-type C57BL/6 mice were infected with H. polygyrus, the bacterial enteropathogen Citrobacter rodentium, or both. We found that MyD88 knockout mice co-infected with H. polygyrus and C. rodentium developed more severe intestinal inflammation and elevated mortality compared to the wild-type mice. The enhanced susceptibility to C. rodentium, intestinal injury and mortality of the co-infected MyD88 knockout mice were found to be associated with markedly reduced intestinal phagocyte recruitment, decreased expression of the chemoattractant KC, and a significant increase in bacterial translocation. Moreover, the increase in bacterial infection and disease severity were found to be correlated with a significant downregulation of antimicrobial peptide expression in the intestinal tissue in co-infected MyD88 knockout mice. Our results suggest that the MyD88 signaling pathway plays a critical role for host defense and survival during helminth and enteric bacterial co-infection.