棉褐带卷叶蛾安徽种群不同日龄雌蛾性信息素的个体变异

采用单个性信息素腺体分析技术对棉褐带卷叶蛾安徽种群６个不同日龄,雌蛾性信息素二元组分进行了定量分析。结果表明各日龄组雌蛾的性信息素含量差异显（Ｐ＜０．０１）,随着雌蛾日龄的增加,性信息素含量呈现由低到高,再由高到低的变化曲线。二元组分中Ｚ－１１－１４：Ａｃ的比例具有较狭窄的个体变异范围（ＣＶ％＝６．４３）;而Ｚ－９－１４：Ａｃ的ＣＶ％＝１５．９１。羽化当天和１天的雌蛾性信息素中Ｚ－９－１４：Ａｃ     

Cyclin G2 is degraded through the ubiquitin-proteasome pathway and mediates the antiproliferative effect of activin receptor-like kinase 7

We have previously reported that Nodal, a member of the TGF-β superfamily, acts through activin receptor-like kinase 7 (ALK7) to inhibit ovarian cancer cell proliferation. To determine the mechanism underlying their effects, a cell cycle gene array was performed and cyclin G2 mRNA was found to be strongly up-regulated by Nodal and ALK7. To study the function and regulation of cyclin G2 in ovarian cancer cells, expression constructs were generated. We found that cyclin G2 protein level decreased rapidly after transfection, and this decrease was prevented by 26S proteasome inhibitors. Immunoprecipitation and pull-down studies showed that ubiquitin, Skp1, and Skp2 formed complexes with cyclin G2. Knockdown of Skp2 by siRNA increased, whereas overexpression of Skp2 decreased cyclin G2 levels. Nodal and ALK7 decreased the expression of Skp1 and Skp2 and increased cyclin G2 levels. Overexpression of cyclin G2 inhibited cell proliferation whereas cyclin G2-siRNA reduced the antiproliferative effect of Nodal and ALK7. Taken together, these findings provide strong evidence that cyclin G2 is degraded by the ubiquitin–proteasome pathway and that Skp2 plays a role in regulating cyclin G2 levels. Furthermore, our results also demonstrate that the antiproliferative effect of Nodal/ALK7 on ovarian cancer cells is in part mediated by cyclin G2.     

MicroRNA-27a Negatively Modulates the Inflammatory Response in Lipopolysaccharide-Stimulated Microglia by Targeting TLR4 and IRAK4

microRNA, a family of small non-coding RNA, plays significant roles in regulating gene expression, mainly via binding to the 3′-untranslated region of target genes. Although the role of miRNA in regulating neuroinflammation via the innate immune pathway has been studied, its role in the production of inflammatory mediators during microglial activation is poorly understood. In this study, we investigated the effect of miR-27a on lipopolysaccharide (LPS)-induced microglial inflammation. miR-27a expression was found to be rapidly decreased in microglia by real-time polymerase chain reaction (real-time PCR) after LPS stimulation. Over-expression of miR-27a significantly decreased the production of inflammatory cytokines, such as interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and nitric oxide (NO), whereas knockdown of miR-27a increased the expression of these inflammatory factors. We also demonstrated by loss- and gain-of-function studies that miR-27a directly suppressed the expression of toll-like receptor 4 (TLR4) and interleukin-1 receptor-associated kinase 4 (IRAK4)—a pivotal adaptor kinase in the TLR4/MyD88 signaling pathway—by directly binding their 3′-UTRs: knocking down TLR4 or IRAK4 in microglia significantly decreased TLR4 or IRAK4 expression and inhibited the downstream production of inflammatory mediators. Moreover, the inflammatory cytokines IL-6 and IL-1β were regulated by IRAK4, whereas TNF-α and NO were more dependent on TLR4 activation. Thus, miR-27a might regulate the LPS-induced production of inflammatory cytokines in microglia independently of TLR4 and IRAK4. Taken together, our results suggest that miR-27a is associated with microglial activation and the inflammatory response.     

Transformation of Saussurea involucrata by Agrobacterium rhizogenes: Hairy root induction and syringin production

Agrobacterium rhizogenes-mediated genetic transformation of Saussurea involucrata was investigated. Four bacterial strains, A4, LBA 9402, R1000 and R1601 and three explant types, leaf blade, petiole and root, were examined. Over 100 hairy root lines were successfully established with strains R1601, R1000 and LBA9402, but none with A4. The highest transformation efficiency of 67% was achieved by using strain R1601 with root explants. One hairy root line isolated from this combination, HR1601-1, produced up to 43.5 ± 1.13 mg syringin g⁻¹ dw, which is about 50-fold higher than that in the wild type plants.Two other lines, HR1000-1 and HRLBA9402-1, isolated from R1000- and LBA9402-transformed roots, respectively, also displayed high capacity of syringin production, being 32.5 ± 3.08 and 39.7 ± 1.37 mg syringin g⁻¹ dw. These three lines were characterized in detail. Polymerase chain reaction analyses confirmed these root lines were of A. rhizogenes origin.     

The thymic stromal cell line MTSC4 induced thymocyte apoptosis in a non-MHC-restricted manner

Mouse thymic stromal cell line 4 (MTSC4) is one of the stromal cell lines established in our laboratory. While losing the characteristics of epithelial cells, they express some surface markers shared with thymic dendritic cells (TDCs). To further study the biological functions of these cells, we compared the capability of MTSC4 with TDCs in the induction of thymocyte apoptosis, using thymic reaggregation culture system. Apoptosis of thymocytes induced by MTSC4 and TDCs was measured by Annexin V and PI staining and analyzed by flow cytometry. We found that MTSC4 selectively augmented the apoptosis of CD4^ 8^ (DP) thymocytes. This effect was Fas/FasL independent and could not be blocked by antibodies to MHC class I and class II molecules. In addition, MTSC4 enhanced the apoptosis of DP thymocytes from different strains of mice, which implies that MTSC4-induced thymocyte apoptosis is not mediated by the TCR recognition of self peptide/MHC molecules. In contrast to MTSC4, thymocyte apoptosis induced by TDCs was MHC-restricted. Thus, MHC-independent fashion of stromal-DP thymocyte interaction may be one of the ways to induce thymocyte apoptosis in thymus. Our study has also shown that the interaction of MTSC4 stromal cells and thymocytes is required for the induction of thymocyte apoptosis.     

Nuclear retention of the lncRNA SNHG1 by doxorubicin attenuates hnRNPC–p53 protein interactions

The protein p53 plays a crucial role in the regulation of cellular responses to diverse stresses. Thus, a major priority in cell biology is to define the mechanisms that regulate p53 activity in response to stresses or maintain it at basal levels under normal conditions. Moreover, further investigation is required to establish whether RNA participates in regulating p53's interaction with other proteins. Here, by conducting systematic experiments, we discovered a p53 interactor—hnRNPC—that directly binds to p53, destabilizes it, and prevents its activation under normal conditions. Upon doxorubicin treatment, the lncRNA SNHG1 is retained in the nucleus through its binding with nucleolin and it competes with p53 for hnRNPC binding, which upregulates p53 levels and promotes p53‐dependent apoptosis by impairing hnRNPC regulation of p53 activity. Our results indicate that a balance between lncRNA SNHG1 and hnRNPC regulates p53 activity and p53‐dependent apoptosis upon doxorubicin treatment, and further indicate that a change in lncRNA subcellular localization under specific circumstances is biologically significant.     

Condensin-Dependent Chromatin Compaction Represses Transcription Globally during Quiescence

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高秆野生稻内生固氮细菌多样性

高秆野生稻(Oryza alta)是一种重要的种质资源, 其组织内也蕴藏着非常宝贵的功能微生物资源。本实验采用无氮培养基, 从高秆野生稻中分离到43株内生固氮菌, 结合乙炔还原法测定其固氮酶活性。经固氮酶基因(nifH)的PCR扩增检测, 43株内生固氮菌代表菌株均能扩增出固氮酶基因片段。利用IS-PCR DNA指纹图谱和SDS-PAGE全细胞蛋白电泳图谱将获得的菌株聚类为6个类群(I、II、III、IV、V、VI)。对各个类群的代表菌株(ZF3, ZF8, ZF13, ZF15, ZF24, ZF43)进行16S rRNA基因序列测定, 结果表明, 类群I属于土生拉乌尔菌(Raoultella terrigena), 类群II属于类肺炎克雷伯氏菌类肺炎亚种(Klebsiella quasipnmoniae subsp. quasipneumoniae), 类群III属于越南伯克氏菌(Burkholderia vietnamiensis), 类群IV的菌株代表肠秆菌属的一个类群(Enterobacter sp.), 类群V的菌株属于门多萨假单胞菌(Pseudomonas mendocina), 类群VI归属于固氮植物菌(Phytobacter diazotrophicus)。Biolog聚类结果与IS-PCR指纹图谱类型及SDS-PAGE全细胞蛋白聚类结果一致。Biolog板测定结果显示, 来自不同类群的代表菌株对碳源的利用差异显著, 说明野生稻内多样的内生固氮菌从环境中获取碳源和氮素的适应能力较强。     

桃ERF转录因子家族生物信息学分析及 芽萌发相关基因筛选

以中油四号油桃(Prunus persica var. nectarina)为研究对象, 利用MEGA 6.0、MEME、GSDS和DNAMAN 6.0等软件对桃ERF家族数据进行生物信息学分析, 鉴定得到102个ERF转录因子家族基因, 并通过构建系统进化树将这102个基因分为10个子家族(I-X)。基因结构分析表明, 有81个基因不含内含子, 20个基因含有1个内含子, 有1个基因与其它成员差异较大, 含有5个内含子。保守元件分析表明, ERF家族包含20个保守元件, 其中Motif 1、Motif 2和Motif 4都属于AP2/ERF结构域, 同一个保守元件主要出现在同一个子家族中, 并且大部分保守元件的功能未知。VIII子家族基因的荧光定量PCR分析表明, 在桃叶芽处于不同的发育状态时, PpeERF068的表达量存在较大差异, 光照培养箱中培养的桃芽在萌发过程中各时期表达量变化趋势进一步表明该基因可能与叶芽萌发有关, 将其命名为PpeEBB1。该研究为进一步揭示PpeEBB1的分子机制奠定了基础, 并为桃树的栽培管理和熟期调控了提供理论指导。