SINPV基因组酶切图谱及多角体基因的序列分析

用限制性内切酶ＥｃｏＲＩ、ＸａｂＩ、ＸｈｏＩ、ＢａｍＨＩ、ＰｓｔＩ、ＳａｃＩ、ＨｉｄｎⅢ、ＳｍａＩ酶解斜纹夜蛾核多角体病毒广州株基因组ＤＮＡ,分别得到２６、２６、２４、２０、１３、１７、９、１条片段,并算得基因组平均大小为１３６．０ｋｂｐ。以ＡｃＮＰＶ多角体基因的部分读码框为探针,经Ｓｏｕｔｈｅｍ杂交将ＳＩＮＰＶ多角体基因定位于ＸｂａＩＯ片段上。将此片段克隆并序列分析,结果表明ＳＩ     

苹果柠檬酸合酶3基因家族成员鉴定及表达分析

柠檬酸合酶(citrate synthase 3, CS3)是细胞代谢途径中的关键酶之一,其活性调节着生物体的物质和能量代谢过程。本研究旨在从苹果全基因组中鉴定CS3基因家族成员,并进行生物信息学和表达模式分析,为研究苹果CS3基因的潜在功能提供理论基础。利用BLASTp基于GDR数据库鉴定苹果CS3家族成员,通过Pfam、SMART、MEGA5.0、clustalx.exe、ExPASy Proteomics Server、MEGAX、SOPMA、MEME和WoLF PSORT等软件分析CS3蛋白序列基本信息、亚细胞定位情况、结构域组成、系统进化关系以及染色体定位情况。利用酸含量的测定和实时荧光定量PCR (real-time fluorescence quantitative polymerase chain reaction, qRT-PCR)技术检测苹果6个CS3的组织表达和诱导表达特性。苹果CS3基因家族包含6个成员,这些CS3蛋白包括473−608个不等的氨基酸残基,等电点分布在7.21−8.82。亚细胞定位结果显示CS3蛋白分别定位在线粒体和叶绿体。系统进化分析可将其分为3类,各亚家族基因数量分别为2个。染色体定位结果显示,CS3基因分布在苹果不同的染色体上。蛋白二级结构以a-螺旋为主,其次是无规则卷曲,b-转角所占比例最小。筛选的6个家族成员在不同苹果组织中均有表达,整体表达趋势从高到低依次为MdCS3.4相对表达含量最高,MdCS3.6次之,其他家族成员相对表达量依次为MdCS3.3>MdCS3.2>MdCS3.1>MdCS3.5。qRT-PCR结果显示,MdCS3.1和MdCS3.3基因在酸含量较低的‘成纪1号’果肉中相对表达量最高,酸含量较高的‘艾斯达’果肉中MdCS3.2和MdCS3.3基因相对表达量最高。因此,本研究对不同苹果品种中CS3基因相对表达量进行了检测,并分析了其在苹果果实酸合成过程中的作用。结果表明,CS3基因在不同苹果品种中的相对表达量存在差异,为后续研究苹果品质形成机制提供了参考。     

Strong plastid degradation is consistent within section Chondrophyllae,the most speciose lineage of Gentiana

Recovering phylogenetic relationships in lineages experiencing intense diversification has always been a persistent challenge in evolutionary studies, including in Gentiana section Chondrophyllae sensu lato (s.l.). Indeed, this subcosmopolitan taxon encompasses more than 180 mostly annual species distributed around the world. We sequenced and assembled 22 new plastomes representing 21 species in section Chondrophyllae s.l. In addition to previously released plastome data, our study includes all main lineages within the section. We reconstructed their phylogenetic relationships based on protein‐coding genes and recombinant DNA (rDNA) cistron sequences, and then investigated plastome structural evolution as well as divergence time. Despite an admittedly humble species cover overall, we recovered a well‐supported phylogenetic tree based on plastome data, and found significant discordance between phylogenetic relationships and taxonomic treatments. Our results show that G. capitata and G. leucomelaena diverged early within the section, which is then further divided into two clades. The divergence time estimation showed that section Chondrophyllae s.l. evolved in the second half of the Oligocene. We found that section Chondrophyllae s.l. had the smallest average plastome size (128 KB) in tribe Gentianeae (Gentianaceae), with frequent gene and sequence losses such as the ndh complex and its flanking regions. In addition, we detected both expansion and contraction of the inverted repeat (IR) regions. Our study suggests that plastome degradation parallels the diversification of this group, and illustrates the strong discordance between phylogenetic relationships and taxonomic treatments, which now need to be carefully revised.     

冻融交替对长白山不同林型土壤两种温室气体排放的影响

以长白山5种林型土壤(硬阔叶林、红松阔叶林、次生白桦林、长白松林和蒙古栎林)为对象,利用原位培养连续取样法研究了冻融过程中5种林型土壤CO2和N2O排放特征及相关机理.结果 表明:冻融期5种林型土壤是CO2和N2O的源.次生白桦林和红松阔叶林土壤CO2和N2O的平均通量显著高于其他3种林型.除硬阔叶林外,各林型土壤CO...     

微生物学实验网上预习与管理系统及其在实验教学中的应用

实验预习是实验教学的首要环节,是学生在开放实验室高效实验的基本保证.针对我校微生物学实验的教学特点和要求,开发设计了微生物学实验网上预习与管理系统并应用于微生物实验教学中.该系统集学生预习和教师管理于一体,每个实验都包括有实验目的,实验原理、实验材料与仪器设备、实验演示、模拟实验和预习测试等6个环节.教学实践证明,该系统的应用从根本上确保了学生实验预习的质量,使实验教学管理更加规范、标准和高效,有效地保证了微生物实验教学质量.     

大气压辉光放电低温等离子体诱变选育谷氨酰胺转胺酶高产菌株

以茂源链轮丝菌(Streptoverticillium mobaraense)03-10为出发菌株,采用一种新型的裸露电极大气压辉光放电的冷等离子体技术对链霉菌孢子进行诱变。根据双层平板法菌落显色及诱变处理后菌落形态差异快速筛选谷氨酰胺转胺酶高产突变株。突变率、正突变率分别达到42.8%和20.6%。最后复筛选育出具有较好遗传稳定性和形态稳定性的高产突变株G2-1,酶活达到2.73U/mL,比出发菌株提高了82%。     

mTORC1-independent translation control in mammalian cells by methionine adenosyltransferase 2A and S-adenosylmethionine

Methionine adenosyltransferase (MAT) catalyzes the synthesis of S-adenosylmethionine (SAM). As the sole methyl-donor for methylation of DNA, RNA, and proteins, SAM levels affect gene expression by changing methylation patterns. Expression of MAT2A, the catalytic subunit of isozyme MAT2, is positively correlated with proliferation of cancer cells; however, how MAT2A promotes cell proliferation is largely unknown. Given that the protein synthesis is induced in proliferating cells and that RNA and protein components of translation machinery are methylated, we tested here whether MAT2 and SAM are coupled with protein synthesis. By measuring ongoing protein translation via puromycin labeling, we revealed that MAT2A depletion or chemical inhibition reduced protein synthesis in HeLa and Hepa1 cells. Furthermore, overexpression of MAT2A enhanced protein synthesis, indicating that SAM is limiting under normal culture conditions. In addition, MAT2 inhibition did not accompany reduction in mechanistic target of rapamycin complex 1 activity but nevertheless reduced polysome formation. Polysome-bound RNA sequencing revealed that MAT2 inhibition decreased translation efficiency of some fraction of mRNAs. MAT2A was also found to interact with the proteins involved in rRNA processing and ribosome biogenesis; depletion or inhibition of MAT2 reduced 18S rRNA processing. Finally, quantitative mass spectrometry revealed that some translation factors were dynamically methylated in response to the activity of MAT2A. These observations suggest that cells possess an mTOR-independent regulatory mechanism that tunes translation in response to the levels of SAM. Such a system may acclimate cells for survival when SAM synthesis is reduced, whereas it may support proliferation when SAM is sufficient.     

基于生物信息学的致病菌特有基因预测及分析

目的:利用生物信息学方法对致病菌特有基因进行大规模预测,同时探讨致病菌特有基因与致病菌毒力之间的关系。方法:构建致病性细菌蛋白质序列数据库和非致病性细菌蛋白质序列数据库,利用同源性比对的方法(BlastP工具)对致病菌特有基因进行预测;同时从文献中提取与致病菌毒力紧密相关的毒力因子,构建具有代表性的毒力因子分析库,对预测的致病菌特有基因进行比较分析。结果:在致病菌780310个基因中,预测了致病菌特有基因79166个,约占致病菌总基因的10.15%;预测的致病菌特有基因包含了构建的毒力因子分析库中的大部分毒力基因。结论:预测的致病菌特有基因与致病菌毒力紧密相关,大大减少了进一步在致病菌基因组中鉴定毒力基因时整个基因组的数据量。     

一株粘质沙雷氏菌烈性噬菌体污水分离及特性

[目的]以粘质沙雷氏菌(8039)为宿主菌从医院污水中分离噬菌体并对其基本生物学特点进行研究.[方法]四步法污水分离噬菌体;单、双层平板噬菌斑实验筛选烈性噬菌体并观察噬菌斑形态;纯化后2%磷钨酸染色电镜观察;手工法提取噬菌体核酸酶切后琼脂糖凝胶电泳分析;利用双层平板噬菌斑实验测定最佳感染复数和完成一步生长实验.[结果]从医院污水中成功分离出粘质沙雷氏菌烈性噬菌体一株(SM701),该噬菌体有一个正多面体立体对称的头部,头径约64nm,无囊膜,有一长尾,无收缩尾鞘,尾长约143nm;基因组核酸能被双链DNA内切酶BamH Ⅰ及Hind Ⅲ切开,大小约57kb;噬菌斑圆形透明,直径1mm左右(培养12h,),边界清楚;当感染复数(multiplicity of infection,MOI)为10时,子代噬菌体滴度较高;按照一步生长实验结果绘制出一步生长曲线,可知感染宿主菌的潜伏期是约为30min,爆发期约100min,平均爆发量约为630[结论]按照国际病毒分类委员会分类标准,该噬菌体属于长尾噬菌体科(siphoviridae)烈性噬菌体,按照Bradley和Ackermann形态分类法属于B1亚群;噬菌斑与周围红色细菌生长区,颜色差异明显,非常便于观察和计数;噬菌体头部大小和形态与呼吸道病毒中的呼肠病毒和腺病毒最为接近;国内尚未见粘质沙雷氏菌噬菌体相关报道.     

48种中药材的多种提取方法的提取物抑制内皮细胞和癌细胞增殖的活性研究

采用石油醚、二氯甲烷、乙酸乙酯、甲醇、乙醇、水为溶剂顺序或单独提取及热水提取药材,研究这些提取物对HUVEC、Bel-7402、A549细胞增殖的抑制活性,筛选具有抑制内皮细胞和癌细胞增殖活性的药材及其提取方法.本文所研究的48种中药材的不同提取方法的提取物抑制内皮细胞和癌细胞增殖的活性结果表明:41种中药材都具有一定的抗血管生成和/或抗癌细胞活性,其中对HUVEC、Bel-7402和A549细胞增殖明显抑制活性(IC50 ≤10 μg/mL)的药材分别有22种、6种和6种,对3种细胞的增殖都有明显抑制活性(IC50 ≤10 μg/mL)的药材有5种.