植物热激转录因子HSF

高温条件下,生物体普遍的反应是产生热激蛋白。转录水平的调控是热激蛋白基因表达调控的主要方式。热激转录因子通过与热激基因上游调控片段中的热激元件结合来调节热激基因的转录。本文简要介绍了植物热激转录因子的种类、结构、功能及转录调节机制等方面的研究。     

多梳抑制复合体PRC1的核心组分CBX家族蛋白在表观遗传调控中的作用(英文)

研究目的:多梳蛋白家族(PcG)是一类染色质水平上通过表观遗传修饰调控靶基因的转录因子,其主要功能是使其靶基因转录受到抑制进而沉默。PcG通常以多梳蛋白复合体(PRC)的形式存在,目前研究的最多的是PRC1和PRC2。PRC1在PcG对其靶基因进行转录抑制发挥着主要作用。本综述主要论述了哺乳动物中PRC1核心成员CBX蛋白在多梳蛋白调控基因转录过程中发挥的作用及其对胚胎发育、细胞记忆、细胞周期、细胞增殖和肿瘤形成等过程的影响。创新要点:现已有大量有关PcG在表观遗传水平对其靶基因进行修饰转录机制的综述报道,且以PRC1和PRC2为整体来介绍表观遗传调控机制的文章也屡见不鲜。然而,关于PRC1核心成员CBX蛋白在哺乳动中的同源蛋白CBX2、CBX4、CBX6、CBX7、CBX8对哺乳动物个体发育调节及肿瘤发生过程的分子机制并没有系统的论述。本综述主要将这五种CBX蛋白在转录分子水平上的所发挥的功能进行相关的介绍,并且总结了CBX2、CBX4、CBX6、CBX7、CBX8各自最新的研究进展,体现出五种CBX蛋白的共同功能、各自独特的功能及彼此间的相互联系。重要结论:总结了在哺乳动物中的五种CBX蛋白在胚胎发育和肿瘤形成等过程中独特的功能调节机制以及整体的相互作用,发现CBX作为PRC1的核心组分在基因表观遗传调控中发挥着极其重要的作用。     

组蛋白及其乙酰化对转录的调控

组蛋白是染色质的主要成分之一．并与DNA结合形成了染色质的基本单位——核小体。核小体是基因转录的通用抑翻子。在早期胚胎发育的转录调控中．连接组蛋白H1亚型的时序变化与核心组蛋白H4的乙酰化都起了关健作用。核心组蛋白的乙酰化与脱乙酰化影响染色质的构象，并通过激活与抑制两种相反的作用调节转录。     

抑制转录后基因沉默的病毒蛋白及其抑制机制

植物中存在天然的转录后基因沉默机制来消除病毒对其的危害,而病毒也进化出不同的对策来逃避甚至消除这种抑制机制;目前研究发现黄瓜花叶病毒(CMV)的2b蛋白及马铃薯丫病毒(PVY)的HC蛋白等植物病毒蛋白能抑制植物转录后基因沉默,对它们相应的抑制机理已了解。研究转录后基因沉默抑制蛋白不仅有助于阐明RNA沉默的具体过程,也为未来的转录后基因沉默甚至RNAi的调控提供研究工具和思路。     

甜橙ERF B3亚组转录因子的鉴定和表达分析

ERF转录因子是AP2/ERF转录因子大家族的一个主要亚家族,ERF转录因子进一步分为包含B3(IX)在内的6～7个亚组.研究表明ERF B3亚组转录因子在植物抗病反应中发挥重要作用.文章在甜橙基因组数据库中筛选了21个CsERF B3亚组转录因子。通过分析感染黄龙病的柑橘转录组数据发现,有9个ERF B3亚组转录因子在道县野橘、宜昌橙和/或甜橙中有差异表达。在外源激素诱导的表达分析中发现6个甜橙ERF B3亚组转录因子有差异表达.进一步研究发现甜橙ERF B3亚组转录因子为核定位蛋白,且具有转录激活活性.这为研究甜橙ERF B3亚组转录因子在植物抗病反应中的功能分析提供理论基础.     

含内含子的核糖体蛋白基因转录起始位点情况分析

选取69个含内含子的核糖体蛋白基因,抽取其中每个基因转录起始位点附近长度为100个碱基的序列,发现转录起始位点为碱基A的占92.8%,给出由位点状态转移到位点后与位点相邻状态的一步转移概率矩阵P以及由位点前与位点相邻状态转移到位点状态的一步转移概率矩阵.含内含子的核糖体蛋白基因中富含碱基A,T的序列可能有利于基因的转录.     

TaMyb2-Ⅱ的亚细胞定位研究

为了探明TaMyb2-Ⅱ转录因子在细胞中定位的特异性，采用瞬时表达体系，将绿色荧光蛋白基因GFP导入洋葱表皮细胞中，在亚细胞结构水平上研究TaMyb2-Ⅱ转录因子的定位取向。激光共聚焦显微镜观察结果表明，TaMyb2-Ⅱ转录因子主要分布在细胞核中,这为进一步研究该基因的功能及作用途经提供了重要信息。     

调控HIV-1转录和潜伏激活的机制及相关因子(英文)

(1)反式激活蛋白(Tat)是病毒复制的重要因子,正性转录延伸因子b(P-TEFb)是Tat反式激活HIV-1转录所必需的特异性宿主细胞因子,其活性与HIV-1的转录密切相关。(2)在细胞内,无活性7SK snRNP复合体是功能性有活性P-TEFb的贮存和来源。在特定条件下,7SK snRNP复合体发生解离并释放出P-TEFb,从而刺激转录延伸。可以说,P-TEFb的活性受到严格的调控,维持着一种动态的平衡。(3)同时,P-TEFb还存在于一个具有超高转录活性的超级延伸复合体(SEC)中。Tat能将含有两个延伸因子P-TEFb和ELL2的SEC复合体募集至HIV-1长末端结构域(LTR),然后众多因子协同作用有效地增强HIV-1的转录作用。(4)溴区包含蛋白4(Brd4)像Tat一样,将P-TEFb募集至众多细胞基因的启动子区域,促进转录。Brd4也可激活基础水平的HIV-1转录,却对依赖Tat的HIV-1转录具有抑制作用,因为Brd4和Tat竞争性地与P-TEFb结合。(5)鉴于Brd4对Tat依赖性HIV-1转录的抑制作用,寻找能够抑制Brd4的小分子药物,激活HIV-1潜伏,结合高效抗逆转录病毒治疗(HAART),使得彻底根除HIV-1变成可能。Brd4的抑制剂JQ1就是这样的一种小分子,并且已被证明可以在多种细胞模型中激活HIV-1潜伏。     

基于科学史实发展科学思维的教学设计——以"基因指导蛋白质的合成"第1课时为例

在"基因指导蛋白质的合成"第一课时"转录"内容的教学中,以"转基因抗虫棉的Bt抗虫蛋白基因是如何合成Bt抗虫蛋白"为情境,结合科学史资料,引领学生进行系统性的逻辑分析与科学论证,将科学思维融入探究活动中,从而归纳总结转录概念,发展生物学学科核心素养.     

宿主核糖体蛋白在病毒感染中的作用

病毒依赖宿主细胞的蛋白翻译机制来实现有效的复制,从而完成其生命周期并产生新的子代病毒.宿主核糖体蛋白参与病毒转录、增殖和抗病毒免疫应答,对病毒感染具有重要作用.近年来的研究表明核糖体蛋白在病毒转录物的选择性翻译中起着多方面的调节作用.本文综述了宿主核糖体蛋白在病毒感染中的作用的研究进展.     

基于人的视觉系统的小波性能评价

We have constructed a compactly supported biorthogonal wavelet that approximates the modulation transfer function(MTF) of human visual system in the frequency domain.In this paper,we evaluate performance of the constructed wavelet,and compare it with the widely used Daubechies9-7,Daubechies 9-3 and GBCW-9-7 wavelets.The result shows that coding performance of the constructed wavelet is better than Daubechies9-3,and is competitive with Daubechies 9-7 and GBCW-9-7 wavelets.Like Dauechies 9-3 wavelet,the filter coefficients of the constructed waveklet are all dyadic fractions,and the tap is less than Daubechies 9-7 and GBOW 9-7,It has an attractive feature in the realization of discrete wavelet transform.     

梅县方言本字考辨

结合古代文献从音义角度辨析学界考证的几个梅县方言词语的本字,认为:梅县方言中表示田埂的“田sun2”之“sun2”本字应为“唇”;表示霉烂的“mut7”本字应为“殁”;表示刺和讽刺的“tshiuk7”本字应为“”;表示裂开的“pit7”本字应为“片畐”;表示用亮光照视或光线刺眼的“tsha 2”本字应为“晟”。另外,也新考证了表示液体太满而往外流的“iok7”、表示定亲的“tsak7定”之“tsak7”以及表示猜测的“thon2”的本字分别是“氵藥”、“笮”和“团”。     

人白血病细胞系KG1a中P2X7受体的表达和功能研究

用半定量RT-PCR和流式细胞术，研究了白血病细胞系KG1a中P2X7受体在基因和蛋白水平的表达。用荧光分光光度计，测定了用激动剂三磷酸腺苷（ATP）和苯甲酰苯甲酸ATP（BzATP）刺激前后细胞内钙离子浓度的变化，证明P2X7受体的功能。结果表明：KG1a细胞表达P2X7受体，且在激动剂的刺激下能引起KG1a细胞通过P2X7受体的胞外钙内流；去除胞外钙离子时，激动剂不能引起胞内钙浓度的升高；提示KG1a细胞表达P2X7受体的基因和功能蛋白，激活该受体引起胞外钙离子的内流。     

Science Letters:Assignment of CCR7 gene to chicken chromosome 27 by radiation hybrid panel mapping

The protein encoded by CC chemokine receptor 7 (CCR7) is a member of the G protein-coupled receptor family. This receptor was identified as a gene induced by the Epstein-Barr virus (EBV), and is thought to be a mediator of EBV effects on B lymphocytes. This receptor is expressed in various lymphoid tissues and activates B and T lymphocytes. It has been shown to control the migration of memory T cells to inflamed tissues, as well as stimulate dendritic cell maturation. To map the CCR7 gene in chicken chromosome, a 6 000 rads chicken-hamster radiation hybrid panel (ChickRH6) was used. PCR of samples from ChickRH6 revealed that the location of CCR7 gene is linked to the maker SEQ0347 (6 cR away) with LOD score of 16.6 and that the marker SEQ0347 is located on chromosome 27 at 27 cR of RH (radiation hydrid) map. We compared the corresponding human mRNA sequence with the predicted coding sequence of chicken CCR7 gene, and found that the assembled contig shared a high percentage of similarity with that of the human gene.     

Physical Fitness and Intellectual Achievement

Abstract

The purpose of this investigation is to examine whether or not the physical fitness (max. oxygen intake measured on cycle ergometer) of school children interacts with their intelligence and school achievement. If there is any interaction, will this change from grade 4 to 7? Another question is whether or not the socioeco‐nomic status of the parents is correlated with the children's development of physical fitness. The results show that there is a significant negative relationship between physical fitness (max. oxygen intake) and intelligence in grades 4 and 7, and that this relationship is significantly less pronounced in grade 7 than in grade 4: while the bright children have a favourable development the dull have an unfavourable development of physical fitness from ages 10 to 14. No relationship was found between physical fitness and school achievement in grades 4 and 7. Both in grades 4 and 7 there was found a significant relationship between the socioeconomic status of the parents and the children's physical fitness. No change in this relationship was found from ages 10 to 14.     

S7—200的网络通信

S7—200系列PLC可方便地实现相互之间通信以及与其它智能设备进行通信。本文介绍了由S7—200 PLC组建的集中典型网络的通信协议和硬件连接设置。S7—200可支持多种通信协议,如点到点接口（PPI）、多点接口（MPI）和PROFIBUS—DP协议。这些协议的结构是基于7层开放系统互联参考模型（OSI）,通过一个令牌环网来实现。     

S7—200的网络通信

S7—200系列PLC可方便地实现相互之间通信以及与其它智能设备进行通信。本文介绍了由S7—200 PLC组建的集中典型网络的通信协议和硬件连接设置。S7—200可支持多种通信协议,如点到点接口(PPI)、多点接口(MPI)和PROFIBUS—DP协议。这些协议的结构是基于7层开放系统互联参考模型(OSI),通过一个令牌环网来实现。     

Simple groups with orders 2^a3^b5^cp^d, 2^a3^b7^cp^d and 2^a3^b5^c7^d

This work deals with the power exponent r1 and r2 respectively of the maximal and second-maximal prime factors ofthe order of simple K4-group, and the classification for simple {5,7}′-K4-group G (i.e. ｜G｜ can not be divided by 5 nor by 7 or ｜π(G)｜ = 4 ), simple 5′ -K4-group G (i.e. ｜G｜ can not divided by 5 and ｜π(G)｜ =4) and simple 7′-Ea-group G (i.e. ｜G｜ can notdivided by 7 and ｜π(G)｜ =4). It is derived that r1 =1, 2 and 4, and r2 is not greater than 4. All the simple K4-groups with order 2^a3^b5^cp^d, 2^a3^b7^cp^d and 2^a3^b5^c7^d are obtained.     

Social withdrawal,observed peer acceptance,and the development of self-perceptions in children ages 4 to 7 years

Children who think poorly about themselves are considered at-risk for a myriad of negative outcomes. Thus, it is important to explore possible origins of such cognitions, particularly in young children. The purpose of this study was to examine the relations between various nonsocial behaviors (i.e., reticence and social withdrawal), observed peer acceptance at ages 4 and 7 years, and self-perceptions at age 7 years in both boys and girls, respectively.Participants included 163 children (89 females, 74 males) who were seen at age 4 and then again at age 7 years. For girls, results revealed that nonsocial behavior (both reticence and solitary-passive withdrawal) was negatively related to observed peer acceptance at both ages 4 and 7, and peer acceptance, as early as 4 years of age, was found to influence self-perceptions of competence at age 7 years. For boys, results revealed that (a) reticence at age 7 predicted negatively to perceived peer acceptance, perceived physical and perceived cognitive competence at age 7 years, (b) solitary-passive withdrawal at age 4 predicted positive cognitive self-perceptions at age 7, and (c) solitary-passive withdrawal at age 7 predicted negatively to perceived peer acceptance and perceived physical competence at age 7 years.     

Science Letters：IGFBP7 plays a potential tumor suppressor role against colorectal carcinogenesis with its expression associated with DNA hypomethylation of exon 1

Insulin-like growth factor binding-protein-7 （IGFBP7） was obtained from our previous colonic adenocarcinoma （CRC） and normal mucosa suppression subtraction hybridization （SSH） cDNA libraries. By RT-PCR and immunohistochemistry, we found that IGFBP7 was overexpressed in CRC tissue compared to normal tissue. However, our in vitro experiments performed in 10 CRC cell lines showed that IGFBP7 expressed only in SW480 and Caco2 cell lines, which implied an underlying reversible regulatory mechanism. Using methylation-specific PCR （MSP） and bisulfite sodium PCR （BSP）, we found that its expression was associated with DNA hypomethylation of exonl. This was further supported by the in vitro study which showed restored IGFBP7 expression after demethylation agent 5-aza-2＇-deoxycytidine treatment. Correlation analysis between IGFBP7 expression and prognosis indicated that overexpression of IGFBP7 in CRC tissue correlated with favourable survival. Investigation of the functional role of IGFBP7 through transfection studies showed that IGFBP7 protein could inhibit growth rate, decrease colony formation activity, and induce apoptosis in RKO and SW620 cells, suggesting it a potential tumor suppressor protein in colorectal carcinogenesis. In conclusion, our study clearly demonstrated that IGFBP7 plays a potential tumor suppressor role against colorectal carcinogenesis and its expression is associated with DNA hypomethylation of exon 1.