云南药用野生稻BIBAC文库混合克隆池制备及筛选

在已构建完成的云南药用野生稻BIBAC( binary bacterial artificial chomosome)文库的基础上,将文库制备成一、二、三级混合克隆池,各级混合池的数量分别为3 360、140和14个.根据Xa21抗病基因序列设计1对特异引物,利用4步PCR法对文库混合克隆池进行逐级筛选,初步确定了3个抗病基因阳性克隆.为今后以PCR法高效利用云南药用野生稻BIBAC文库挖掘其优异基因奠定了良好的基础.     

水稻白叶枯病广谱抗性基因Xa21导入两用不育系培矮64S

以克隆的Xa21基因为外源基因,成熟胚愈伤组织为转化受体,应用农杆菌介导法对水稻两用型核不育系培矮64S进行转化,获46株转基因植株。PCR和Southern分析结果表明,Xa21已整合到受体基因组。用稻白叶枯病病原菌(Xanthomonasoryzaepv.oryzae)菲律宾小种6号接种鉴定,结果表明大多数转基因植株获得了抗病性。已整合的Xa21基因能够稳定地遗传,在所检测转基因株系的T1代中,Xa21基因显示3:1的分离。     

以胞质分裂阻滞法研究女性年龄与体细胞中 21号染色体分离异常的关系

21三体是人类最常见的先天性疾病,约95%患儿的超数21号染色体来源于母亲,且随母龄增加患儿出生率也随之增加。本文首次运用胞质分裂阻滞法(CB法)对不同年龄女性体细胞进行荧光原位杂交,对其21号染色体的分离情况进行分析。结果表明,随年龄的增加,女性体细胞中21号染色体不分离也随之增加,但21号染色体丢失无年龄效应, 且21号染色体不分离频率远高于其丢失。该结果表明,女性体细胞中21号染色体不分离与生殖细胞同样存在年龄效应。 Abstract　　Trisomy 21 is the most common genetic desease in human. More than 90% is derived from mother. With the advancing of mother's age, the frequency of trisomy 21 is increasing. We detected the relation between chromosome 21 missegregation and age in cytokinesis-blocked female lymphocytes by　in situ　hybridization with chromosome 21 specfic probe. We have found that the age effect also exists in female somatic cells as in gamets.     

FGF1:一种治疗糖尿病的新型潜在药物

糖尿病是一种常见的内分泌代谢性疾病,它及其并发症的治疗是现代医学仍未解决的难题。常见的药物治疗有诸多不良反应,譬如胰岛素的长期使用会产生胰岛素耐受性。近年研究发现,酸性成纤维细胞因子（Fibroblast growth factor 1,FGF1或aFGF）及其衍生物能够使2型糖尿病小鼠的血糖快速恢复至正常水平,并且具有胰岛素增敏效果,规避了胰岛素治疗产生耐受性的问题。因此,人们对FGF1及其衍生物在开发新型T2DM疗法方面给予诸多期待。该综述系统介绍了FGF1的结构与功能、降糖功效的机制及新发现,对FGF1的2种注射方式和FGF家族在降糖作用方面进行了比较,并对FGF1在治疗糖尿病方面的研究进程进行展望,旨在为调节血糖、解决胰岛素耐受性问题提供一种新的思路和方法。     

Circulating tumor microemboli: Progress in molecular understanding and enrichment technologies

Circulating tumor cells (CTCs) and their clusters, also known as circulating tumor microemboli (CTM), have emerged as valuable tool that can provide mechanistic insights into the tumor heterogeneity, clonal evolution, and stochastic events within the metastatic cascade. However, recent investigations have hinted that CTM may not be mere aggregates of tumor cells but cells comprising CTM exhibit distinct phenotypic and molecular characteristics in comparison to single CTCs. Moreover, in many cases CTM demonstrated higher metastatic potential and resistance to apoptosis as compared to their single cell counterparts. Thus, their evaluation and enumeration may provide a new dimension to our understanding of cancer biology and metastatic cancer spread as well as offer novel theranostic biomarkers. Most of the existing technologies for isolation of hematogenous tumor cells largely favor single CTCs, hence there is a need to devise new approaches, or re-configure the existing ones, for specific and efficient CTM isolation. Here we review existing knowledge and insights on CTM biology. Furthermore, a critical commentary on current and emerging trends in CTM enrichment and characterization along with recently developed ex-vivo CTC expansion methodologies is presented with the aim to facilitate researchers to identify further avenues of research and development.     

DGCR8‐mediated disruption of miRNA biogenesis induces cellular senescence in primary fibroblasts

The regulation of gene expression by microRNAs (miRNAs) is critical for normal development and physiology. Conversely, miRNA function is frequently impaired in cancer, and other pathologies, either by aberrant expression of individual miRNAs or dysregulation of miRNA synthesis. Here, we have investigated the impact of global disruption of miRNA biogenesis in primary fibroblasts of human or murine origin, through the knockdown of DGCR8, an essential mediator of the synthesis of canonical miRNAs. We find that the inactivation of DGCR8 in these cells results in a dramatic antiproliferative response, with the acquisition of a senescent phenotype. Senescence triggered by DGCR8 loss is accompanied by the upregulation of the cell‐cycle inhibitor p21CIP1. We further show that a subset of senescence‐associated miRNAs with the potential to target p21CIP1 is downregulated during DGCR8‐mediated senescence. Interestingly, the antiproliferative response to miRNA biogenesis disruption is retained in human tumor cells, irrespective of p53 status. In summary, our results show that defective synthesis of canonical microRNAs results in cell‐cycle arrest and cellular senescence in primary fibroblasts mediated by specific miRNAs, and thus identify global miRNA disruption as a novel senescence trigger.     

Alteration in gene expression profile and biological behavior in human lung cancer cell line NL9980 by nm23-H1 gene silencing

Lung cancer is the leading cause of cancer death in both men and women. Tumor metastasis is an essential aspect of lung cancer progression. nm23-H1 is a metastasis suppressor gene. The molecular mechanism by which nm23-H1 suppresses the metastasis is still unclear. Here, we compared the gene expression profile of human large cell lung cancer cell line NL9980 by nm23-H1 gene silencing with that of negative control cells to comprehensively investigate nm23-H1-mediated changes in gene expression of NL9980 cells. Microarray assay revealed that expression of 733-known genes (1.9%, 733/38,500) were altered in response to nm23-H1 gene silencing, including 466 upregulated genes and 267 downregulated. real-time PCR assay of the expression changes indicated that 81.82% (45/55) of verified genes were consistent with that observed in microarray assay. The upregulated genes included MMP-1, -2, SNAI2, CXCL1, 2, 3, PAI-2, while the downregulated genes included cystatin B, TIMP-2, E-cadherin, centrin-2, all of which have been associated with tumor metastasis. Furthermore, we confirmed by Western blot that the expression of MMP-1 and -2 were significantly increased while that of cystatin B was dramatically decreased in NL9980-nm23-H1 silencing cells. The NL9980-nm23-H1 silencing cells exhibited significantly more S phase growth and invasive ability. Thus, silencing of nm23-H1 gene caused metastasis-related gene expression changes in lung cancer cells. The knockdown of nm23-H1 expression may change the lung cancer cells to a more invasive phenotype through alteration in the expression of a set of genes.     

大肠癌P21,P53蛋白表达和k—ras基因,P53基因突变研究

用免疫组化技术和ＰＣＲ－ＳＳＣＰ技术对高、中、低分化大肠腺癌、癌旁粘膜、正常粘膜及大肠腺癌型息肉的Ｐ２１、Ｐ５３蛋白表达和ｋ－ｒａｓ基因、Ｐ５３基因突变进行检测。结果,大肠腺癌Ｐ２１、Ｐ５３蛋白表达比大肠腺瘤增多,但增加不显著（Ｐ〉０．０５）,二组均比癌旁粘膜和正常粘膜Ｐ２１、Ｐ５３蛋白表达阳性率高（Ｐ〈０．０１）,大肠腺癌ｋ－ｒａｓ基因和Ｐ５３基因突变率比大肠腺瘤、癌旁粘膜和正常粘膜组显著增加     

Ro52蛋白的分子生物学研究进展

Ro52蛋白作为靶抗原,存在于多种自身免疫性疾病,如干燥综合征、系统性红斑狼疮、皮肌炎等患者的血清中。Ro52蛋白是TRIM蛋白家族成员(TRIM21),其分子内含有RING-finger、B-box、卷曲螺旋结构域,分别具有不同的生物学功能。Ro52蛋白在免疫防御中的作用日渐为研究者所关注,如Ro52与IgG分子的作用、Ro52作为一种E3泛素连接酶与其他信号分子的作用等。其自身泛素化和广泛的泛素化作用已经在Ro52与干扰素的作用中得到了体现。迄今,Ro52在自身免疫性疾病中的具体致病机制还不清楚。我们尝试通过介绍Ro52的分子生物学特点及其与相关活性分子的相互作用的最新研究进展,初步探索其可能的致病机制。     

分子标记辅助选择改良蜀恢527对白叶枯病的抗性

以含抗性基因Xa2 1和Xa4的抗白叶枯病近等基因系IRBB6 0为供体亲本 ,以不抗白叶枯病强恢复系蜀恢5 2 7为轮回受体亲本 ,连续回交 3代 ,自交 1代 ,在分离世代用分别与Xa2 1和Xa4紧密连锁的标记pTA2 48和MP12对目标基因Xa2 1和Xa4进行辅助选择 ,直至BC3F2 。在BC3F2 中选出株型、粒型、播抽期等农艺性状与蜀恢 5 2 7相似且pTA2 48和MP12的扩增带型纯合的 10个单株 ,用 10 0个RAPD和 12 0对SSR引物进行背景选择 ,决选出 5个单株 ,作为改良的蜀恢 5 2 7。抗性分析表明 ,这些改良的蜀恢 5 2 7株系对我国菌系CⅠ CⅦ和来自菲律宾的P1 和P6 均表现抗性 ,说明抗性基因已成功导入蜀恢 5 2 7中并表达。同时对pTA2 48和MP12在亲本间的多态性和选择的准确性也进行了分析 ,结果显示这两个标记在亲本间的多态性明显 ,共显性 ;选择的准确率分别在 97%和 83%以上 ,可以用其进行标记辅助选择。