凹耳蛙SOX基因的PCR-SSCP分析

SOX基因家族是一类与SRY基因高度相关的转录调控因子,具有一个保守基序HMG—box,可以与DNA序列特异性结合,促进基因的特异转录,从而在胚胎发育及性别分化中起着重要作用。本文采用PCR方法,扩增了凹耳蛙的SOX基因保守区,获得长约220bp的片段;SSCP分析结果显示凹耳蛙SOX基因雌雄个体片段无差异,与人的有较大差异,本文为探讨凹耳蛙的性别决定机制及SOX基因的进行提供了分子资料。     

小麦SOD基因的电子克隆及生物信息学分析

以NCBI中的EST数据库为主要数据来源,以一系列生物信息学软件为工具,进行了超氧化物歧化酶（SOD）基因的电子克隆及生物信息学分析。结果表明：通过电子克隆方法获得了SOD基因的编码区全长序列,该预测的SOD蛋白质氨基酸序列与数据库中同类基因的蛋白质氨基酸序列具有极高的相似性,并且含有完整的保守结构域;电子克隆到的SOD基因编码的不是分泌蛋白,也不是膜蛋白,而是胞质蛋白。通过某个基因的一个EST序列采用电子克隆的手段进行基因全长的电子拼接是可行的。     

不同禽类Mel 1c基因克隆及生物信息学分析

为进一步研究克隆到的鹅、鸭、鹌鹑、斑鸠Mel 1c基因,对该序列进行特征分析,为Mel 1c基因的功能研究打下基础。参考NCBI其它物种的序列设计引物,克隆得到鹅、鸭、鹌鹑、斑鸠Mel 1c基因的部分c DNA序列,并对其编码的蛋白进行生物信息学分析。鹌鹑、鸭、鹅和斑鸠的Mel 1c部分片段,长度为850bp,编码283个氨基酸。通过分析鹌鹑、鸭、鹅和斑鸠Mel 1c的结构表明符合褪黑素受体的结构特征,含有一N端在胞内六个跨膜结构域,属于G蛋白偶联受体家族。该蛋白质为分泌蛋白,包含一个信号肽,其剪切位点位于26和27之间(VVA-VY)。同源性比对结果表明不同物种间Mel 1c基因序列及氨基酸序列的同源性较高均大于71%,Mel 1c在进化过程中比较保守。鹅、鹌鹑、斑鸠、鸭和原鸡的核酸和氨基酸的同源性最高分别大于92%和96%。Mel 1c符合进化规律,斑鸠、鹌鹑、鹅和鸭属于高等的非哺乳类脊椎动物,处于分子进化树的最顶层。     

拟南芥和水稻Cel基因家族的生物信息学分析

运用生物信息学方法对拟南芥和水稻各25个Cel基因的系统进化、基因结构、蛋白质结构等进行分析。结果表明,50个Cel属于糖苷水解酶家族9,分为3个亚家族(GH9A、GH9B、GH9C),GH9C是进化的祖先;Cel基因编码的蛋白质均有保守的GH9催化结构域,GH9A有跨膜结构域和胞质结构域,GH9B有信号肽,GH9C有跨膜结构域、纤维素结合结构域和信号肽;GH9A和GH9C在基因结构和保守基序显示较高的保守性,GH9B具有多样性;Cel基因编码的蛋白质为两性稳定蛋白,二级结构主要是无规则卷曲和α-螺旋,亚细胞定位于细胞膜或细胞壁,大部分是分泌蛋白,有1个跨膜螺旋。     

甜橙CsLOB1基因克隆、表达及干涉载体构建

为探讨高感溃疡病‘纽荷尔’脐橙CsLOB1基因序列特征及其响应柑橘溃疡菌侵染表达特点,利用同源序列法从‘纽荷尔’脐橙叶片中克隆得到CsLOB1基因CDS全长并进行序列分析.实时荧光定量法检测‘纽荷尔’脐橙叶片接种溃疡菌后CsLOB1基因表达变化.结果表明,CsLOB1基因CDS序列全长714 bp,编码237个氨基酸.理化性质预测分析表明CsLOB1蛋白为亲水性蛋白质;保守域预测表明,CsLOB1蛋白含有LBD基因家族LOB保守结构域.系统进化树分析表明,‘纽荷尔’脐橙与克里曼丁橘CsLOB1蛋白同源性高于其它非柑橘类植物.实时荧光定量PCR分析显示,柑橘溃疡菌接种后,‘纽荷尔’脐橙叶片CsLOB1基因表达显著上调.采用gateway克隆技术进一步构建CsLOB1基因RNAi干涉载体,为柑橘抗溃疡病种质的创建建立基础.     

稻纵卷叶螟一个DELTA家族谷胱甘肽S-转移酶基因的克隆、序列分析与表达模式

谷胱甘肽S-转移酶（glutathione S-transferases ,GSTs）在昆虫代谢各种内源和外源性有害化合物的过程中起关键作用。重要水稻害虫稻纵卷叶螟（Cnaphalocrocis medinalis）的GST基因目前尚无研究。本实验克隆了一个稻纵卷叶螟delta家族GST基因的全长cDNA序列,命名为CmGSTd3（Genbank登录号KM433686）。CmGSTd3包含681 bp的开放阅读框,编码一个由226个氨基酸组成的蛋白。CmGSTd3蛋白是一个胞质GST ,与已知的昆虫delta家族GST 具有较高的同源性。在系统进化分析中,CmGSTd3与家蚕的delta家族GST聚在同一进化分支上。实时荧光定量PCR结果显示,CmGSTd3基因在稻纵卷叶螟幼虫阶段表达量最高,且主要表达于幼虫的中肠和脂肪体,由此推测其可能参与了体内异源毒物的代谢。本研究为探索CmGSTd3的生理功能奠定了前期基础。     

长足大竹象超长链脂肪酸延长酶家族的全基因组鉴定及其分子进化

超长链脂肪酸延伸酶（Elongation of very long chain fatty acids protein;ELO)是决定长足大竹象(Cyrtotrachelus buqueti)脂肪酸生物合成的关键酶。利用生物信息学方法对长足大竹象ELO基因家族的基因结构特征及其编码蛋白序列进行详细的分析以期探究长足大竹象ELO基因家族调控其脂肪酸生物合成的分子机制。结果表明,从长足大竹象基因组序列中共鉴定出15个ELO基因家族成员,分别位于四条染色体上。其等电点9.22～9.68、呈碱性。该家族蛋白具有稳定性、疏水性、具有跨膜现象、且有多个磷酸化位点、二级结构以α-螺旋为主。Cbu ELO蛋白家族共鉴定出10个保守基序。通过构建Cbu ELO蛋白家族进化树分析,长足大竹象与赤拟谷盗的ELO蛋白家族亲缘关系最近。该研究结果为深入探索长足大竹象ELO基因的功能提供了参考依据。     

大豆Shaker家族全基因组鉴定

Shaker家族基因参与植物对低钾环境胁迫的响应过程,可帮助植物从土壤中吸收钾素。本研究通过生物信息学方法对大豆Shaker基因家族的全基因组鉴定与分析,从大豆中共鉴定出11个Shaker基因,染色体定位表明大豆Shaker家族基因分布在8条不同的染色体上,大豆Shaker家族蛋白在系统进化上分为3组,家族内的成员具有相似的基因结构和结构域,家族基因的外显子/内含子数量较多且基因序列较长,启动子区有大量逆境相关的反应元件,表明GmShaker基因家族可能在响应非生物胁迫中发挥重要作用。     

Septin基因家族分类及其生理功能的研究进展

Septin是一类广泛存在于除植物外所有真核生物中的具有鸟苷三磷酸(GTPase)活性的保守基因家族,参与胞质分裂、胞内物质转运及细胞凋亡等一系列重要生理功能。弄请septin基因家族的分类及功能将有助于我们深入认识septin与人类疾病的关系。     

全外显子测序结合先天性心脏病相关基因过滤在一家族性房间隔缺损家系中检测出新的致病突变TBX20(D176N)(英文)

研究目的:寻求该房间隔缺损家系遗传致病原因。创新要点:1.鉴定出一个全新的家族性房间隔缺损相关性TBX20突变;2.首次使用全外显子测序结合先天性心脏病相关基因过滤的方法来研究小家系遗传致病因素;3.TBX20的T-box DNA结合域的突变与先天性心脏病有关。研究方法:对一个临床发现的房间隔缺损家系(图1a)的先证者进行全外显子测序,运用公共数据库过滤后,使用先天性心脏病相关基因再次过滤,得到了19个候选基因;然后,运用SIFT、Polyphen-2和MutationTaster等软件预测,排除了13个多态性位点(表2);最后,运用共分离检测(聚合酶链式反应产物直接测序),找到该家系致病的遗传因素,即TBX20基因发生了错义突变(D176N)(图2),该突变位点在ESP和dbSNP数据库中也未曾发现,且该位点在多种生物中高度保守(图1c)。重要结论:1.本研究发现的TBX20突变(D176N)是该房间隔缺损家系致病的原因,同时该突变位点为世界上首次报道;2.全外显子测序结合先天性心脏病相关基因过滤是一个分析小家系遗传致病因素的有效又经济的方法。     

“The Nation Stands Behind You”: Mobilizing Social Support on 38pitches.com

This research explored social support expressions to and for Boston Red Sox pitcher, Curt Schilling, in response to troubling events he disclosed on his blog, www.38pitches.com. An interpretive analysis of 514 comments posted by blog readers to Schilling's blog entries was conducted. The analysis revealed that, via their supportive postings, blog readers emerged as a mobilized support group who authenticated Schilling's identity as a sports media critic and active sports media participant while also cementing his legacy in Red Sox culture. The analysis suggests that blogs possess valuable public relations utility for professional athletes, particularly for those who have combative relationships with sports journalists, as social support is covertly obtained, enabling professional athletes to preserve “face” while simultaneously garnering support for their views.     

Application of cDNA array for studying the gene expression profile of mature appressoria of Magnaporthe grisea

Appressorium is an infection structure of the phytopathogenic fungus Magnaporthe grisea. Analysis of gene expression profiles ofappressorium development provides insight into the molecular basis of pathogenicity and control of this fungal plant disease. A cDNA array representing 2927 unique genes based on a large EST （expressed sequence tag） database ofM. grisea strain Y34 was constructed and used to profile the gene expression patterns at mycelium and appressorium maturation stages. Compared with mycelia, 55 up-regulated and 22 down-regulated genes were identified in mature appressoria. Among 77 genes, 16 genes showed no similarity to the genome sequences of M. grisea. A novel homologue of peptidyl-prolyl cis-trans isomerase was found to be expressed at low-level in mature appressoria of M. grisea. The results indicated that the genes such as pyruvate carboxylase, phospholipid metabolism-related protein and glyceraldehyde 3-phosphate dehydrogenase involved in gluconeogenesis, lipid metabolism and glycolysis, showed differential expression in mature appressoria. Furthermore, genes such as PTHll, beta subunit of G protein and SGTI involved in cell signalling, were expressed differentially in mature appressoria. Northern blot analysis was used to confirm the cDNA array results.     

基因组重排的反转排序的近似算法

本文主要研究基因无方向的基因组重排的反转排序问题.本文算法基于断点图的概念,给出一个时间复杂性为O(maxb3(π),nb(π)),空间复杂性为O(n)的求解近似最优解的算法,其中n为基因组中基因个数,π=(π1,π2,...πn)表示n个基因的一种排列,b(π)表示排列π中的断点数.数据试验的结果表明,该近似算法可以求得较好的结果.     

Beyond the Central Dogma: Model-Based Learning of How Genes Determine Phenotypes

In an introductory biology course, we implemented a learner-centered, model-based pedagogy that frequently engaged students in building conceptual models to explain how genes determine phenotypes. Model-building tasks were incorporated within case studies and aimed at eliciting students’ understanding of 1) the origin of variation in a population and 2) how genes/alleles determine phenotypes. Guided by theory on hierarchical development of systems-thinking skills, we scaffolded instruction and assessment so that students would first focus on articulating isolated relationships between pairs of molecular genetics structures and then integrate these relationships into an explanatory network. We analyzed models students generated on two exams to assess whether students’ learning of molecular genetics progressed along the theoretical hierarchical sequence of systems-thinking skills acquisition. With repeated practice, peer discussion, and instructor feedback over the course of the semester, students’ models became more accurate, better contextualized, and more meaningful. At the end of the semester, however, more than 25% of students still struggled to describe phenotype as an output of protein function. We therefore recommend that 1) practices like modeling, which require connecting genes to phenotypes; and 2) well-developed case studies highlighting proteins and their functions, take center stage in molecular genetics instruction.     

How genes evolve

The increasing power of molecular techniques of gene cloning, DNA sequencing and use of restriction enzymes has revolutionised our ability to understand mechanisms of evolution at the level of genes. Exciting new findings on pseudogenes and gene elongation have led to an increased understanding of how our genes themselves change through evolutionary time, often in bizzarre ways.     

苏云金芽孢杆菌及其在害虫防治上的应用(综述)

苏云金芽孢杆菌 (Bacillusthuringiensis,简称Bt)自 1 90 1年发现以来 ,一直在微生物学、昆虫学和生物化学等方面受到研究者的关注。由于Bt能形成对许多昆虫具特异性毒力的杀虫蛋白 ,因此从 1 959年开始Bt已被制成杀虫剂防治鳞翅目害虫。近 1 0年来 ,随着分子生物学和遗传工程技术的成熟和发展 ,使人们增加了有关晶体形成的分子生物学知识。Bt的杀虫活性主要是其能产生含有杀虫晶体蛋白 (ICPs)的伴孢晶体。一些杀虫蛋白基因 (又称cry基因 )已经成功用于转基因抗虫植物中。本文将从Bt微生物学、Bt制剂在害虫防治中以及Btcry基因在转基因抗虫植物中的应用等方面作一综述。     

百合转基因体系及分子育种相关基因的研究进展

通过分子育种的方法来改良百合品质以及开发新品种,是百合育种工作的热点之一.笔者在本文中对百合转基因体系建立的各种影响因素进行了探讨,综述了百合转基因分子育种中关注较多的报告基因、抗虫害基因、花发育相关基因等方面的现状及发展.     

A Study of Two Instructional Sequences Informed by Alternative Learning Progressions in Genetics

Learning progressions (LPs) are hypothetical models of how learning in a domain develops over time with appropriate instruction. In the domain of genetics, there are two independently developed alternative LPs. The main difference between the two progressions hinges on their assumptions regarding the accessibility of classical (Mendelian) versus molecular genetics and the order in which they should be taught. In order to determine the relative difficulty of the different genetic ideas included in the two progressions, and to test which one is a better fit with students’ actual learning, we developed two modules in classical and molecular genetics and alternated their sequence in an implementation study with 11th grade students studying biology. We developed a set of 56 ordered multiple-choice items that collectively assessed both molecular and classical genetic ideas. We found significant gains in students’ learning in both molecular and classical genetics, with the largest gain relating to understanding the informational content of genes and the smallest gain in understanding modes of inheritance. Using multidimensional item response modeling, we found no statistically significant differences between the two instructional sequences. However, there was a trend of slightly higher gains for the molecular-first sequence for all genetic ideas.