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.     

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.     

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.     

A computer generator for randomly layered structures

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

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to