Puzzle out the regulation mechanism of PI4KⅡα activity

<正>Phosphatidylinositol 4-kinaseⅡα(PI4KⅡα),the most abundant PI4K in mammalian cells,is best known for its essential role in providing the substrate for phosphatidylinositol 3-kinase(PI3K),an important kinase for phospholipid signaling.PI4KIIα also plays important roles in membrane trafficking,phagocytosis and the exo-endocytic cycle of synaptic vesicles.Its dysfunction results in tumor growth,spastic paraplegia and Gaucher’s disease.Therefore,PI4KIIα may potentially be an important drug target.     

Increased leptin by hypoxic-preconditioning promotes autophagy of mesenchymal stem cells and protects them from apoptosis

Autophagy is the basic catabolic progress involved in cell degradation of unnecessary or dysfunctional cellular components.It has been proven that autophagy could be utilized for cell survival under stresses.Hypoxic-preconditioning(HPC)could reduce apoptosis induced by ischemia and hypoxia/serum deprivation(H/SD)in bone marrow-derived mesenchymal stem cells(BMSCs).Previous studies have shown that both leptin signaling and autophagy activation were involved in the protection against apoptosis induced by various stress,including ischemia-reperfusion.However,it has never been fully understood how leptin was involved in the protective effects conferred by autophagy.In the present study,we demonstrated that HPC can induce autophagy in BMSCs by increased LC3-II/LC3-I ratio and autophagosome formation.Interestingly,similar effects were also observed when BMSCs were pretreated with rapamycin.The beneficial effects offered by HPC were absent when BMSCs were incubated with autophagy inhibitor,3-methyladenine(3-MA).In addition,down-regulated leptin expression by leptin-shRNA also attenuated HPC-induced autophagy in BMSCs,which in turn was associated with increased apoptosis after exposed to sustained H/SD.Furthermore,increased AMP-activated protein kinase phosphorylation and decreased mammalian target of rapamycin phosphorylation that were observed in HPC-treated BMSCs can also be attenuated by down-regulation of leptin expression.Our data suggests that leptin has impact on HPC-induced autophagy in BMSCs which confers protection against apoptosis under H/SD,possibly through modulating both AMPK and mTOR pathway.     

RAPD分析在绢丝昆虫亲缘关系研究中的应用Ⅱ.柞蚕品种间的遗传差异

采用RAPD技术,对5个柞蚕品种的遗传差异进行比较研究.结果表明,所采用的40个随机引物中,有27个引物扩增谱带清晰且重复性较好,扩增总片段数253条,单个引物的扩增片段数在4～16之间,片段大小在0.33～3.0kb之间.不同柞蚕品种间的遗传差异较小,遗传距离(D)在0.066～0.1659之间,根据D值,由UPGMA聚类分析软件绘制了它们的分子进化树。 Abstract:Random amplified Polymorphic DNA (RAPD) was used to analyze the genetic diversity among Antheraea pernyi.The genetic variance of five Antheraea pernyi was studied.The result showed that:27 of 40 arbitrary primers could amplify clear and repeating bands.A total of 262 fragments were obtained.Each primer gave 4~16 bands and the average was 9.7.The length of the band was 0.33~3.0kb.The D value between different breeds of Antheraea pernyi was 0.066~0.1659.The D value was used to construct a dendrogram by UPGMA.     

筛选机制与细胞衰老的DNA损伤假说

生物界存在一类筛选机制,它将DNA损伤较小的细胞筛选出来,产生后代.主要有两类模式机制1和机制2,分别以细菌和人的成纤维细胞为代表,那些具有筛选机制1的细胞(如:细菌、生殖细胞、癌细胞)能无限传代,而体细胞则不能.这两类筛选机制背后有更深刻的原因,而细胞的癌变正是从机制2退化为机制1的过程。 Abstract:Selective mechanisms exist in organism and biosphere,which select the cells with less DNA injuy and reproduces them.There are two models;Mechanisms 1 and Mechanisms 2,represented respectively b bacteria and mechanolytes of human beings.Cells with Mechanisms 1(e.g. bacteria,generative cells,cancer cells)can reproduce infinitely,while somatic cells can not.There are deep-going reasons behind the two categories of selective mechanisms.The canceration of the cells is a degenerating process from Mechanisms 2 to Mechanisms 1.     

植物基因工程表达载体的改进和优化策略

外源基因在转基因植物中表达效率低一直是令相关研究者困扰的一个问题.转基因植物的生物安全性最近在全球范围内开始引起世人的担忧.本文简要介绍了近年来在植物表达载体构建方面所采用的一些新策略,这些策略有助于增强外源基因的表达水平、提高生物工程体的安全性。 Abstract:The low expression level of foreign genes in transgenic plants is a puzzling question for researchers in plant genetic engineering.The biosafety concern is now causing a growing public wariness of transgenic plants around the world.This article reviews the new strategies currently used in construction of plant expression vector for plant genetic engineering.These strategies are important for obtaining better expression of foreign genes and developing safer transgenic plants.     

人工湿地系统对污水磷的净化效果

建立以亚热带湿生、水生植物为主的十二套下流行一上流－上行流人工湿地系统作为处理城镇生活污水的对策。以其中四套研究其在不同的水力负荷及气候条件下对污水中磷的去除效果。人工湿地系统随处理运行时间的推移趋于稳定,对污水中的总磷、无机磷显示较好的净化效率,平均去除率在冬季达到４０％以上,夏季达到６０％以上,出水达到国家地面水Ⅲ级标准。水生植物在系统中起到明显作用,有植物系统的除磷效率及稳定性均高于无植物对照,其中２号茭白－石菖蒲系统的效果最好,总磷平均去除率为６５％。４号9蔗－苔草系统在高水力负荷下的净效果优于２号。水力负荷的增加对系统的净效果没有明显影响。     

Vaccinia virus infection induces dendritic cell maturation but inhibits antigen presentation by MHC class II

Vaccinia virus (VV) infection is known to inhibit dendritic cells (DC) functions in vitro. Paradoxically, VV is also highly immunogenic and thus has been used as a vaccine. In the present study, we investigated the effects of an in vivo VV infection on DC function by focusing on early innate immunity. Our data indicated that DC are activated upon in vivo VV infection of mice. Splenic DC from VV-infected mice expressed elevated levels of MHC class I and co-stimulatory molecules on their cell surface and exhibited the enhanced potential to produce cytokines upon LPS stimulation. DC from VV-infected mice also expressed a high level of interferon-beta. However, a VV infection resulted in the down-regulation of MHC class II expression and the impairment of antigen presentation to CD4 T cells by DC. Thus, during the early stage of a VV infection, although DC are impaired in some of the critical antigen presentation functions, they can promote innate immune defenses against viral infection.