家蚕线粒体ND2、COⅠ和若干tRNA基因的克隆及序列分析

克隆并测定了家蚕（Bombyx mori）线粒体基因组3468bp的EcoRⅠ和HindⅢ双酶一段序列,根据序列同源性比较,该DNA片段包括3个蛋白质编码基因：ND2基因、COⅠ基因和COⅡ基因5′端399bp的序列,以及6个tRNA基因和一个尚待确定的tRNA^Met基因。家蚕与果蝇的ND2基因序列同源性约69.7%,COⅠ基因的同源性约83.8%,COⅡ基因5′端的同源性约80％,这表明细胞色素氧化酶基因在物种间比烟酰胺腺漂呤二核苷酸脱氢酶基因保守,6个推定的tRNA基因序列与果蝇相应tRNA基因序列差异较大,另外,除tRNA^Chn基因的二级结构相似外,其它tRNA基因的二级结构与果蝇相应tRNA基因的二级结构也有较大差异。     

条斑紫菜多糖PY-D2对4种人肿瘤细胞株生长的影响

目的:研究条斑紫菜多糖体外抗肿瘤的生物学活性。方法:应用生化技术分离和纯化条斑紫菜多糖,获得条斑紫菜多糖的2个组分,分别为PY-D1和PY-D2;在体外培养条件下分别用不同浓度的条斑紫菜多糖PY-D2处理4种人肿瘤细胞,通过MTT法观察条斑紫菜多糖PY-D2对4种人肿瘤细胞生长的影响;采用流式细胞仪检测肿瘤细胞的细胞周期变化。结果:条斑紫菜多糖PY-D2诱导HO-8910、MCF-7、K562和7721肿瘤细胞72h后,对其生长有明显的抑制作用,呈剂量依赖效应,500mg/LPY-D2的抑制率分别为21.2%、23.6%、19.8%和21%(P<0.001)。流式细胞仪检测表明PY-D2可以阻滞肿瘤细胞的细胞周期于G0/G1期或G2/M期。结论:条斑紫菜多糖PY-D2具有抑制肿瘤细胞HO-8910、MCF-7、K562和7721生长的作用,其有关的分子生物学作用机理值得进一步研究。     

镉胁迫对不同品种小麦幼苗生长和生理特性的影响

以4个小麦品种(豫麦4、扬麦15、宝丰7228和宁麦13)为材料,研究了镉胁迫对水培条件下小麦幼苗生长和抗氧化酶系统的影响.结果表明:镉胁迫条件下植株的生长、叶绿素合成及硝酸还原酶活性明显受到抑制;植株体内与氧化胁迫有关的CAT和POD活性下降,H2O2和MDA含量上升;4个品种在镉处理后生长抑制和氧化胁迫程度上表现不同,显示出对镉耐性的差异,其中扬麦15对镉耐性高于其他3个品种.     

O-GlcNAc修饰蛋白质的生理功能和研究方法

氧连N-乙酰葡糖胺（O-GlcNAc）修饰是与磷酸化相类似的蛋白质翻译后修饰方式,它主要发生在细胞核和细胞质中的蛋白质上．与细胞信号通路密切相关,成为近年来的研究热点。该文主要从O-GlcNAc修饰蛋白质的生理功能和研究方法两方面介绍该领域近年来的研究成果。     

Tet1 and Tet2 regulate 5-hydroxymethylcytosine production and cell lineage specification in mouse embryonic stem cells

TET family enzymes convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. Here, we show that Tet1 and Tet2 are Oct4-regulated enzymes that together sustain 5hmC in mouse embryonic stem cells (ESCs) and are induced concomitantly with 5hmC during reprogramming of fibroblasts to induced pluripotent stem cells. ESCs depleted of Tet1 by RNAi show diminished expression of the Nodal antagonist Lefty1 and display hyperactive Nodal signaling and skewed differentiation into the endoderm-mesoderm lineage in embryoid bodies in?vitro. In Fgf4- and heparin-supplemented culture conditions, Tet1-depleted ESCs activate the trophoblast stem cell lineage determinant Elf5 and can colonize the placenta in midgestation embryo chimeras. Consistent with these findings, Tet1-depleted ESCs?form aggressive hemorrhagic teratomas with increased endoderm, reduced neuroectoderm, and ectopic appearance of trophoblastic giant cells. Thus, 5hmC is an epigenetic modification associated with the pluripotent state, and Tet1 functions to regulate the lineage differentiation potential of ESCs.     

茶碱与胃蛋白酶相互作用的光谱性质研究

采用紫外光谱法和荧光光谱法研究了茶碱与胃蛋白酶的结合作用。观测到茶碱使胃蛋白酶的紫外吸收峰增强,特征荧光峰淬灭。Stern-Volmer淬灭曲线显示,茶碱对胃蛋白酶的荧光淬灭很可能是一个单一的静态淬灭过程。     

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.     

金色蝗属的分类研究及一新种记述（直翅目: 剑角蝗科）

本文记述采自内蒙古贺兰山地区金色蝗属Chrysacris 1新种, 即白纹金色蝗Chrysacris albonemus Zheng, Zhang et Zeng sp. nov. 该新种近似于山间金色蝗Chrysacris montanis Zhang et Zheng, 1993, 主要区别为: 1)头顶及头部背面具中隆线; 2)前胸背板沟前区长为沟后区长的1.6~1.8倍; 3)前翅前缘脉域宽为中脉域宽的1.5~2倍。附有金色蝗属分种检索表。模式标本保存于陕西师范大学动物研究所昆虫标本室。     

铁线蕨中间纤维的研究及某些植物类角蛋白的比较分析

应用整装电镜制样技术,结合选择性抽提方法在铁线蕨（ＡｄｉａｎｔｕｍｐｈｉｌｉｐｐｅｎｓｅＬ．）叶细胞中观察到直径１０ｎｍ的纤维网络结构。免疫印迹结果显示：经选择性抽提得到的纤维蛋白与动物角蛋白抗体有免疫交叉反应,间接免疫荧光标记也得到类似结果,而且此类蛋白能在体外自组装为１０ｎｍ或更粗的纤维。说明蕨类植物细胞中存在类角蛋白中间纤维网络。免疫印迹结果表明,螺旋藻（ＳｐｉｒｕｌｉｎａｓｕｂｔｉｌｌｉｓｉｎａＫｕｔｚ．）细胞,地钱（ＭａｒｃｈａｎｔｉａｐｏｌｙｍｏｒｐｈａＬ．）叶状体,铁线蕨（Ａ．ｐｈｉｌｉｐｐｅｎｓｅＬ．）、银杏（ＧｉｎｋｇｏｂｉｌｏｂａＬ．）、白菜（ＢｒａｓｉｃａｐｅｋｉｎｅｎｓｉｓＲｕｐｒ．）的叶组织经选择性抽提后得到的蛋白均与动物角蛋白抗体有免疫交叉反应。其中,螺旋藻仅含有两种类酸性角蛋白,而其余４种植物材料均含有３种类酸性角蛋白及３种类碱性角蛋白。结合以往实验结果,我们认为类角蛋白在植物细胞中是普遍存在的。     

京津冀地区新型城镇化对土地生态效率影响的实证分析

近年来, 城市化进程的不断推进对城市土地利用及生态环境产生了极大影响。选取城镇化发展最为迅速与典型的京津冀地区作为研究区域, 采用超效率DEA模型及Malmquist效率指数, 从经济学角度分析2006-2015年土地生态效率的时空演变, 随后, 基于人口、富裕和技术(STRIPAT)模型, 构建新型城镇化发展水平的综合指标评价体系, 分析新型城镇化对土地生态效率的影响。研究结果表明: 京津冀地区城镇化发展水平与土地生态效率之间存在显著的正相关关系, 即城镇化水平的不断提升对土地生态效率的提高具有积极作用, 各城市土地生态效率在新型城镇化发展背景下存在明显的空间差异, 此外, 土地利用与管理技术水平的提高、环境政策的改变等均会对土地生态效率的提升产生积极影响。这项研究旨在为提高城市土地管理水平, 推动城市可持续发展提供决策支持。