鸽源大肠杆菌分离鉴定、毒力基因检测及药敏试验

为了确定疑似细菌感染鸽的病原菌,以病死鸽为研究对象,进行病原菌的分离培养、生化鉴定、16S rDNA序列分析、血清型检测、动物致病性试验、毒力基因检测以及药敏试验。结果表明:此次分离的1株优势菌株,命名为QH-1,是短杆状、中等大小的革兰氏染色阴性菌,且其形态特征和生化鉴定特性与大肠杆菌相符;经16S rDNA序列分析进一步证实菌株QH-1为大肠杆菌;血清型检测结果显示,分离菌株QH-1为O26血清型分离株;动物致病性试验结果显示,分离菌株QH-1能引起鸽和小白鼠感染发病,且试验鸽发生与自然感染病例相似症状;毒力基因检测结果显示,大肠杆菌QH-1携带irp2,FyuA毒力基因;药敏试验结果显示,大肠杆菌QH-1对头孢曲松敏感;对阿莫西林、环丙沙星等耐药。疑似细菌感染的鸽病例为大肠杆菌的感染,可以选择头孢曲松进行防控。     

规模化鸡场粪样和苍蝇产CMY-2大肠杆菌中耐药基因与毒力基因调查及其共转移研究

为了解全国20家规模化鸡场粪样和苍蝇产CMY-2大肠杆菌中耐药基因与毒力基因的流行现状及其共转移情况,对2013-2015年间分离自粪样和苍蝇中的549株大肠杆菌,采用聚合酶链反应（PCR）方法筛选出blaCMY-2阳性菌株;脉冲场凝胶电泳（PFGE）分析blaCMY-2阳性菌株的遗传进化关系;K-B纸片法检测阳性菌株对13种抗菌药物的耐药性;利用PCR技术检测19种相关耐药基因以及14种毒力基因;接合转移试验和质粒复制子分型研究耐药基因及毒力基因的传播方式。结果,33株大肠杆菌呈CMY-2阳性,阳性率为6.0 %,且均表现为多重耐药;检测到15种耐药基因（blaTEM-1、blaCTX-M-55、blaOXA-1、qnrBDS、aac(6’)-Ib-cr、oqxA、tetA、tetC、sul1、sul2、sul3、rmtB和flor）和4种毒力基因（iutA、traT、fyuA和VagC）;33株携带blaCMY-2基因菌株中有21株接合转移成功,blaCMY-2基因可通过lncA/C或lncI1质粒与耐药基因（blaTEM-1、blaCTX-M-55、tetA或sul2）和（或）毒力基因（traT或VagC）共同转移。本研究阐明了规模化鸡场产CMY-2大肠杆菌携带耐药基因与毒力基因的情况,证实了细菌中质粒介导的耐药与毒力的共转移,为耐药性传播及疾病防控提供了参考。     

引起舟山地区凡纳滨对虾急性肝胰腺坏死病病原的分离与鉴定

2014-2019年期间,从舟山地区疑似发生急性肝胰腺坏死综合病(acute hepatopancreatic necrosis disease, AHPND)对虾体内共分离到30株病原菌。通过16S r RNA基因及gyrB、rpoA等基因同源性检索分析对30株分离菌进行了鉴定;同时运用Nested-PCR方法筛选并鉴定了菌株pirABVP基因携带情况;选取代表性菌株,以浸泡感染方法进行了致病性试验。分离菌鉴定结果显示:从舟山地区凡纳滨对虾肝胰腺中分离到的病原菌主要以副溶血弧菌、坎贝氏弧菌及欧文斯氏弧菌为主;其中10株菌携带pirABVP毒力基因;本实验选取4株pirABVP基因阳性菌和1株pirABVP基因阴性菌进行了感染试验;致病性试验显示,携带pirABVP毒力基因的4株菌可使健康对虾发病,出现急性肝胰腺坏死病的典型症状,且持续暴露于病原菌的实验对虾的最高死亡率可达95%,比短时间暴露组死亡率高40%左右;发病虾肝胰腺及肠道组织出现了肝胰腺小管崩塌及肠绒毛脱落等严重的病理变化。研究表明,携带pVA1质粒的副溶血弧菌、欧文斯氏弧菌和坎贝氏弧菌等多种弧菌诱发了舟山地区对虾AHPND,养殖环境中的AHPND致病菌持续存在会导致对虾死亡率处于高水平状态。     

海南罗非鱼源维氏气单胞菌的分离、毒力基因检测及ERIC-PCR分型

从海南罗非鱼的体内分离和鉴定出40株维氏气单胞菌,并对这40株维氏气单胞菌进行了8种毒力基因检测及ERIC-PCR分型分析.毒力基因检测的结果表明:在这40株维氏气单胞菌中,主要携带6种毒力基因,即act,alt,ast,fla,lip和hlyA基因,其携带率分别为35.0%,22.5%,27.5%,37.5%,5.0%和15%,未能检测到TapA和aerA基因;根据不同菌株携带毒力基因的不同,这40株维氏气单胞菌又可分为13种毒力基因型,携带2种以上毒的菌株有15株,占总数的37.5%,携带3种以上毒力基因的菌株有9株,占总数的22.5%,其中HNWC23携带5种毒力基因,其毒力基因型为act~+alt~+ast~+hly A~+fla~+.ERIC-PCR分型结果显示:该40株维氏气单胞菌可分为四个大簇,以遗传相似度(96%)为界可将其分为18种ERIC型,每个簇中的ERIC型都呈现多样性.     

秦皇岛地区狐源致病性E.coli对四环素类药物耐药性和耐药基因的检测

为了确定秦皇岛地区狐源大肠杆菌(E.coli)对四环素类药物的耐药性和耐药基因分布,采用常规的鉴定方法,从不同养狐场送检的腹泻的狐狸体内分离鉴定出20株E.coli。致病性试验表明,该菌为致病性E.coli。药敏试验结果表明:分离菌株对四环素和强力霉素药率分别达到95%和90%。通过PCR方法检测分离菌株四环素类药物的耐药基因,结果显示,tet A和tet B基因的检出率分别为100%和95%。本研究为秦皇岛地区防治狐源致病性大肠杆菌病提供实验基础。     

应用多重PCR法鉴定产志贺样毒素大肠杆菌毒力基因

目的：从各种来源的标本中快速鉴定STEC毒力基因，并了解其在菌株中的分布情况．方法：采用多重PCR的方法鉴定STEC的特征性毒力因子stx1，six2，eaeA和hlyA．结果：各种标本中鉴定出产志贺毒素的大肠杆菌共46株，38株(82．6％)携带stx1基因，30株(65．2％)具有six2基因，22株(47．8％)同时检测到2种基因．36株(78．3％)检测到hlyA基因，24株(52．2％)有eaeA基因．4种毒力基因即six1 stx2 eaeA hlyA的有19株(41．3％)，而且血清型均为O157．结论：产志贺样毒素大肠埃希菌毒力基因图谱是一个重要的分子流行病学标志，应用多重PCR可简便、快速、敏感、特异性地鉴定出STEC的特征性毒力基因，并依照毒力基因存在情况判定其致病性能．     

规模化鸡场中产CMY-2大肠杆菌耐药基因与毒力基因的调查及共转移研究

调查规模化鸡场中产CMY-2大肠杆菌耐药基因与毒力基因的流行现状及共转移情况,对549株来源于鸡场粪样和苍蝇的大肠杆菌进行blaCMY-2PCR检测;K-B法检测耐药表型;PCR扩增19种相关耐药基因和14种毒力基因;接合试验和质粒复制子分型研究耐药基因与毒力基因的共转移.结果显示:6.0%(33/549)大肠杆菌呈CMY-2阳性,且均为多重耐药;检测到15种耐药基因和4种毒力基因,其中floR,blaTEM-1,sul2,sul1,traT,VagC检出率较高;63.6%产CMY-2大肠杆菌中blaCMY-2基因可通过lncA/C或lncI1质粒与耐药基因和(或)毒力基因共转移.本研究表明规模化鸡场粪样和苍蝇源产CMY-2大肠杆菌已成为耐药基因和毒力基因的重要储存库,携带二者质粒的转移导致耐药与毒力的传播扩散.     

广东地区感染养殖罗非鱼的无乳链球菌分子分型研究

以广东省内5个罗非鱼Oreochromis niloticus主要养殖区内分离的无乳链球菌Streptococcus agalactiae为研究目标,通过毒力基因PCR检测、多位点序列分型、脉冲场凝胶电泳技术研究广东地区感染罗非鱼的无乳链球菌分子特征。结果发现170株分离无乳链球菌中毒力基因的携带率介于60.59%~100%之间,毒力基因携带形成10个谱系,dltR-bca-sod A-spb1-cfb-bac(38.24%,65/170),dltr-bca-sod A-spb1-bac(23.53%,40/170)和dltr-bca-sod A-spb1-cfb-bac-scp B(22,35%,38/170)为主要的谱系,dltr-bca-sod A-spb1-bac-scpb(8.24%,14/170)和dltr-bca-sod A-spb1(4.71%,8/170)次之。多位点序列分型研究证实170株菌在7个位点均为单一的等位基因,为adh P(10),phe S(1),atr(2),gln A(1),sdh A(3),glc K(2),tkt(2),序列型为ST7型。146株菌脉冲场凝胶电泳结果表明146株菌分为6个簇(A-D,F,G),相似性介于86%~100%之间。A(18),B(16),C(103),D(7)为主要的遗传簇,占菌株数的98.63%(144/146)。基因簇A,C在4个采样区均有发现;基因簇B分布在吴川、茂名和阳江;基因簇D分布在茂名、珠海和阳江;基因簇F和G分别来自茂名和珠海。在A-D遗传簇中均有发现来自不同地区的菌株呈现100%的相似性,为同一克隆株。结果表明广东省主要罗非鱼养殖区内感染链球菌携带毒力基因比率高,序列型均为高致病的ST7型别,不同地区间具有相同的PFGE型别,不同地区间交叉传播感染的可能高。     

秦皇岛地区貂源肠外致病性大肠杆菌四环素类耐药表型与基因型相关性分析

为分析秦皇岛地区貂源肠外致病性大肠杆菌对四环素类药物的耐药性及耐药基因之间关系,对秦皇岛地区分离的20株貂源肠外致病性大肠杆菌采用K-B药敏纸片法,选择常见的3种四环素类药物进行耐药性的检测,并通过PCR扩增对其耐药基因进行判定。结果表明:20株肠外致病性大肠杆菌中,多重耐药菌株占75%,多重耐药基因的菌株占100%,耐药基因检出和耐药性结果比较表明,四环素、强力霉素、土霉素对5种耐药基因的符合率在88.89%～100%之间。     

H5N1亚型禽流感毒株A/Duck/HuBei/3/2005的分子特征及致病性研究

采用分子生物学方法,对1株2005年从湖北省某县分离获得的禽流感病毒株(A/Duck/HuBei/3/2005)进行全基因组序列测定.序列分析显示,该分离株为H5N1亚型.HA蛋白在HA1和HA2连接处,含有连续多碱性氨基酸模体(-RRKKR-).根据进化分析结果,分离株A/Duck/HuBei/3/2005的7个基因来源于2004～2005年湖南地区流行株(CK/HN/999/05,DK/HN303/04),但是PA基因片段发生了重排,来源于野禽.动物实验显示DK/HB/3/05对鸡和鸭均具有高致病性;对小鼠有较低致病性.     

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.     

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.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has