抗农作物病原真菌微生物的筛选及其聚酮合酶基因的分析

以5种农作物病原真菌为指示菌,从湖北省神农架地区的土壤中筛选得到1株抗真菌放线菌,命名为ⅡR21菌株.经过形态观察、培养特征、生理生化分析和16S rDNA序列同源性分析,初步鉴定该菌株属于链霉菌属.发酵液稳定性研究表明：ⅡR21菌株发酵液在－20℃～80℃范围内具有较强的稳定性;在pH 4.0～7.0范围内,ⅡR21菌株发酵液的抑菌活性比较稳定;紫外光照射对发酵液的抑菌活性没有影响.对放线菌ⅡR21菌株中Ⅰ型PKS基因族中KS基因进行PCR扩增和分析,与其他KS序列相似性比较低,与其系统分类最近的Streptomyces natalensis相似性达77%.     

汕头南澳海绵Halichondria sp.放线菌分离的研究

海绵相关微生物是药物开发的重要资源.本文利用6种培养基对汕头南澳普遍存在的海绵Halichondria sp.的共附生放线菌进行分离和培养,共得到36株放线菌.基于16S rRNA基因序列的系统发育分析表明,这些放线菌分别属于Streptomyces、Nocardiopsis和Micromonospora属.抗菌活性筛选结果显示,分离菌株分别对Staphylococcus aureus、Bacillus subtilis和Escherichia coli等的生长有抑制作用.同时分子方法筛选显示这些放线菌具有潜在产生聚酮类、角蒽环类和非核糖体多肽类的能力.本研究结果为海绵相关微生物在药物开发方面积累了基础数据.     

内生放线菌A00122中germicidin生物合成基因的克隆

在植物和细菌中,Ⅲ型聚酮合酶能够产生种类多样的次生代谢产物.在药用植物内生放线菌A00122的发酵产物中,分离到了一个已知的Ⅲ型聚酮类化合物germicidin.对A00122菌株建立了基因组文库,根据已知的同源基因Sco7221设计引物作为探针对文库进行PCR筛选,并通过Southern杂交的方法从阳性克隆5-3-10中定位了包含germi-cidin基因的片段,经测序得到长度为1 185 bp的完整合成基因.该基因的获得为深入研究Ⅲ型聚酮合酶的底物选择性,通过定向改造的方法获得非天然Ⅲ型聚酮类化合物提供了重要基础.     

具有抗农作物病原真菌活性链霉菌Ⅰβ1菌株的筛选鉴定及其聚酮合酶基因分析

从土壤中筛选出一株具有抗农作物病原真菌活性链霉菌,命名为Ⅰβ1.根据生理生化特性对其进行了鉴定及16S rRNA基因序列同源性比对,分析了该菌株的发酵滤液抑菌稳定性和聚酮合酶基因.结果表明:该菌株初步鉴定为链霉菌属,Ⅰβ1菌株发酵滤液在温度为-20~55℃,紫外线照射10~30 min,pH为1.0~9.0条件下均较稳定,聚酮合酶基因在其系统分类上与Streptomyces noursei ATCC 11455制霉菌素生物合成基因簇的聚酮合酶基因分枝较近.     

溶藻弧菌HY9901鞭毛蛋白flaC基因的克隆和序列分析及真核表达质粒的构建

参照GenBank上登录的副溶血弧菌鞭毛蛋白flaC基因序列设计引物,PCR扩增溶藻弧菌HY9901株的flaC全长基因,序列分析结果显示该基因为1 155 bp,编码384个氨基酸.与GenBank中其他弧菌的同源基因序列比对显示,溶藻弧菌flaC基因与副溶血弧菌flaC基因的同源性最高(87%).将该基因定向克隆到真核表达质粒pcDNA3.1(+)中,获得带溶藻弧菌鞭毛蛋白flaC基因的真核表达重组质粒pcDNA-flaC,为其DNA疫苗的进一步研究奠定了基础.     

红树林土壤微生物模块化聚酮合酶基因(簇)及其多样性研究

聚酮类化合物(Polyketide)是一类重要的具有药用价值的生物活性分子.通过宏基因组学技术获得了红树林土壤微生物中模块化聚酮合酶(Polyketide Synthase,PKS)基因(簇),并对其多样性进行了研究.首先构建了该红树林土壤微生物的16SrDNA文库,初步分析了红树林土壤样本的细菌群落组成,发现许多菌群曾经被报道存在PKS基因簇,约占整个细菌群落的75%.利用相关菌群的PKS酮基合成酶结构域(Ketosynthase,KS)的保守区域序列信息设计简并引物,并构建了KS DNA序列文库.经测序获得131条新型KS序列,该结果表明红树林土壤微生物中蕴含了许多新型的聚酮类化合物合成酶.为了进一步获得聚酮合酶基因(簇),我们通过土壤微生物宏基因组Cosmid文库的构建与筛选,得到了13个属于trans-AT PKS,cis-AT PKS,NRPS/PKS Hybrid等类型的聚酮合酶的基因(簇),并通过构建KS序列的系统进化树分析了样本中聚酮合酶的多样性组成.     

美洲雁源金黄色葡萄球菌的PCR检测

本试验对从临床病死美洲雁的病料中分离得到的一株致病菌进行了16s rRNA基因片段的扩增,将扩增产物与pMD18-T载体连接构建克隆载体,经PCR和酶切鉴定正确后测序,测序结果与GenBank中已注册菌株的16s rRNA基因序列进行同源性比较,结果与金黄色葡萄球菌的序列同源性达到97%.由此判定感染病鸭的是金黄色葡萄球菌.     

副猪嗜血杆菌hhdB-A基因的鉴定和分析

为了明确副猪嗜血杆菌致病菌株的毒力相关因子,从广东省不同地区发病猪场送检病猪中分离到9株细菌(H1～H9),并对其hhdB-A基因进行了鉴定和分析。结果显示,所分离的9株细菌经形态观察、生化特性鉴定和PCR鉴定为副猪嗜血杆菌阳性,并具有卫星现象和不溶血特征。用hhdB-A基因引物从分离菌株中扩增到了特异性片段,序列分析表明,所获得的hhdA基因序列与GenBank中副猪嗜血杆菌SH0165,HPS59的hhdA基因同源性为98%～100%,分离菌株hhdA基因之间序列同源性为99.0%～99.9%;hhdB基因序列与SH0165的hhdB基因同源性为99%,分离菌株hhdB基因之间序列同源性为97.5%～99.8%;推导的氨基酸序列与少数放线杆菌、杜克雷嗜血杆菌的溶血素蛋白具有一定的相似性。RT-PCR扩增到了hhdB-A基因的目的条带,表明该基因在分离菌株中得到了相应的表达。     

多重耐药鲍曼不动杆菌携带金属酶与整合酶基因特征及同源性分析

目的了解吉林地区多重耐药鲍曼不动杆菌(Multidrug-resistant Acinetobacter baumanni,MDRAB)金属酶与整合酶基因的类型,并对菌株进行同源性分析.方法收集吉林地区2所三级甲等医院临床标本分离鉴定的鲍曼不动杆菌38株.多重耐药株携带金属酶的初筛实验-双纸片协同试验:金属酶与整合酶基因的检测-聚合酶链反应(PCR),并对其进行同源性分析.结果在所有MDRAB菌株亚胺培南-EDTA协同试验中,15株(39.4%)阳性,16株(42.1%)携带整合酶基因Ⅰ,2株(5.2%)携带整合酶基因Ⅱ,2株(5.2%)携带blaVIM型金属酶基因,1株(2.6%)携带blaNDM-1型金属酶基因,未检测出金属酶基因blaIMP,blaSIM-1和整合酶基因Ⅲ.结论该地区临床分离的MDRAB耐药率高,可能与其携带金属酶基因和整合酶基因有关,A型MDRAB为医院感染主要流行株.     

柳珊瑚Anthogorgia caerulea相关可培养共生放线菌多样性及其生物毒活性研究

【目的】研究斜阳岛附近海域柳珊瑚Anthogorgia caerulea可培养共生放线菌多样性及其发酵液代谢产物的生物毒活性。【方法】采用纯培养法和基于16SrRNA基因序列的系统发育分析对从广西斜阳岛附近海域采集的柳珊瑚Anthogorgia caeru[ea可培养共生放线菌多样性进行研究,利用卤虫致死法测试其生物毒活性。【结果】从柳珊瑚Anthogorgia caeru[ea中分离获得相关可培养放线菌23株,采用16SrRNA基因序列的系统发育分析后发现,这些菌株属于2个亚纲9个科9个属23种。绝大部分菌株都具有一定的生物毒活性,其中10株菌株有较强生物毒活性,l株有显著毒活性。【结论】广西斜阳岛附近海域柳珊瑚Anthogorgia caeru[ea中存在较为丰富的放线菌多样性,部分菌株具有较强的生物毒活性。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-