准噶尔盆地大沙鼠鼠疫自然疫源地鼠疫耶尔森菌质粒谱的研究

目的 了解和掌握准噶尔瓮地大沙鼠鼠疫自然疫源地鼠疫菌质粒谱类型.方法 提取新疆地区不同鼠疫自然疫源地及青藏高原喜玛拉雅旱獭鼠疫自然疫源地、昆仑山喜马拉雅旱獭鼠疫自然疫源地和内蒙古长爪沙鼠鼠疫自然疫源地的39株鼠疫菌质粒DNA,采用琼脂糖凝胶电泳法对其进行质粒谱图型分析.结果 在检测的26株准噶尔盆地大沙鼠鼠疫自然疫源地鼠疫菌中,有23株质粒谱为6×106、45×106、65×106,3株为6×106、45×106和72×106.结论 准噶尔盆地大沙鼠鼠疫自然疫源地鼠疫菌质粒谱分为两个类型:一为6×106、45×106、65×106质粒谱型,是该疫源地的主要质粒谱型,与邻近的北天山灰旱獭.长尾黄鼠鼠疫自然疫源地及内蒙占长爪沙鼠鼠疫自然疫源地、昆仑山喜马拉雅旱獭鼠疫自然疫源地和青藏高原喜马拉雅旱獭鼠疫自然疫源地的鼠疫菌主要质粒谱型一致;二为6×106、45×106和72×106质粒谱型,为少数型,在我国系首次发现.     

44株中国田鼠型与24株非田鼠型鼠疫菌的DFR检测分析

目的比较我国两个田鼠鼠疫自然疫源地的44株田鼠型鼠疫菌的基因组组成，研究中国田鼠型鼠疫菌的遗传稳定性。方法根据已经证实的22个差异区段(I)FR)设计引物，每株鼠疫菌的每个DFR都采用PCR技术进行验证。结果22个DFR在两种田鼠型鼠疫菌的分布状态完全一致，即均同时缺失了DFR6、DFR11、DFR12、DFR13、DFR18、DFR19和DFR20，与来源于其他鼠疫自然疫源地非田鼠型鼠疫菌的基因组成有显著差别。结论锡林郭勒高原型鼠疫菌和青藏高原青海田鼠型鼠疫菌在基因组组成上高度一致，田鼠型鼠疫菌的基因缺失可能与其对人不致病有关。     

甘宁黄土高原阿拉善黄鼠鼠疫疫源地鼠疫菌的基因分型研究

目的 研究我国甘宁黄土高原阿拉善黄鼠鼠疫疫源地鼠疫菌的基因分型。方法 根据已经证实的22个DFR（差异区段）设计引物，每株鼠疫菌的每个DFR都采用PCR技术进行验证。结果 17株甘宁黄土高原疫源地鼠疫菌株共包括3个基因型，即7、11和13型。7、11和13型所占比例分别为5．9％（1／17）、5．9％（1／17）和88．2％（15／17）。结论 我国甘宁黄土高原阿拉善黄鼠鼠疫疫源地鼠疫菌的基因型主要为13型，而且13型是该疫源地鼠疫菌所特有的基因型。     

天山山地灰旱獭-长尾黄鼠鼠疫疫源地鼠疫菌基因分型研究

目的对天山山地灰旱獭．长尾黄鼠鼠疫疫源地鼠疫菌进行基因分型。方法根据已经证实的22个差异区段（DFR）设计引物，对每株鼠疫菌进行PCR扩增。结果61株天山疫源地鼠疫菌株共包括4个基因型，即1、2、3、4型。基因型1、2和3在北天山疫源地西部鼠疫菌株中都有分布，但尼勒克菌株的基因型全部为1型。南天山疫源地阿合奇和阿图什两个县菌株的基因型存在显著差别，阿合奇菌株基因型与北天山疫源地的菌株比较接近，而3株阿图什菌株的基因型均为4型，与帕米尔高原长尾旱獭鼠疫疫源地鼠疫菌株相同。结论基因分型结果与纪树立的生态分型基本一致。天山疫源地和帕米尔高原疫源地在阿图什县有交叉。     

新疆山地鼠疫自然疫源地鼠疫耶尔森菌基因组分化和演变

目的比较来自我国新疆4大片山地鼠疫自然疫源地的144株鼠疫菌的基因组组成的差别,研究新疆山地鼠疫自然疫源地鼠疫菌的基因分型和进化规律。方法根据已经证实的22个差异区段(DFR)设计引物,每株鼠疫菌的每个DFR都采用PCR技术进行验证。结果新疆4大片山地鼠疫自然疫源地的144株鼠疫菌的基因型DFR图谱可归类为14种,分为7个主要基因组型和7个次要基因组型。西天山北坡灰旱獭-长尾黄鼠鼠疫疫源地存在3个主要基因组型和5个次要基因组型,西段以01型基因组型为主,占种群体的91.7%,02型占8.3%;中段以03型为主,占68.8%,01型占4.2%,02型占20.85%,另有02M1和02M3(02型的突变型)占2.1%,03M1型(03型的突变型)占2.1%;东段以02型为主,89.8%,01型、02M2、02M3和02M4型(02型的突变型)各占2.0%。南天山灰旱獭鼠疫疫源地存在2个主要基因型和1个次要基因型,以4型为主,占66.7%,02型占16.7%, 04M1型(04型的突变型)占16.7%。帕米尔高原-阿赖山红旱獭鼠疫疫源地仅存在04型1种基因型。昆仑山喜马拉雅旱獭鼠疫疫源地分为中昆仑和东昆仑鼠疫自然疫源地,中昆仑山存在2种鼠疫基因组型,以11型为主,占群体的90%,12型占10%;东昆仑山存在3种鼠疫基因组型,以05型为主,占66.7%,02型和11型分别占16.7%。结论新疆山地鼠疫自然疫源地鼠疫菌基因组的演化由3个演化路线组成。西天山北坡鼠疫自然疫源地的鼠疫菌基因组,自西向东在不同的生态地理环境和宿主媒介作用下发生适应性进化和演变,由较为古老的01型基因组逐渐演化为02和03型,最后南下至青海和东昆仑演变为05型,并且在这条演化路线上存在许多演变过程中发生的基因组地域交叉和次要基因组型;南天山和帕米尔高原-阿赖山鼠疫自然疫源地的鼠疫菌的04型基因组型是由01型直接演化而来,并在这一区域形成主要鼠疫基因组型;中昆仑山鼠疫自然疫源地的鼠疫菌基因组型可能是由西藏冈底斯山喜马拉雅旱獭鼠疫源地的鼠疫菌的10型基因组演化而来,形成以11型为主,12型为辅的鼠疫基因组构型特点。     

松辽平原达乌尔黄鼠鼠疫自然疫源地鼠疫菌基因分型

为了研究松辽平原达乌尔黄鼠鼠疫自然疫源地鼠疫耶尔森菌(以下简称鼠疫菌)的基因组成,采用PCR技术对分离自该疫源地88株鼠疫菌进行了基因分型,其中黑龙江4株、吉林43株、辽宁4株、内蒙37株,鼠疫菌DNA均由青海省地方病预防控制所鼠疫菌专业实验室提供。引物设计和PCR扩增方法:在周冬生等鉴定的22个差异区段(DFR)中,有3个位于pMT1质粒中,19个位于染色体上。采用ArrayDesigner2.0软件针对每个DFR各设计1对引物,为了证实pMT1的存在,我们还特意针对pMT1质粒设计了1对引物,引物序列为5′AACACTA TCTCATTCCGCAGTAAAG3′。PCR…     

应用抑制削减杂交技术进行鼠疫耶尔森菌的比较基因组研究

目的确定古典型鼠疫耶尔森菌的特有序列，为建立和完善该菌基因组分型系统提供可靠数据。方法通过抑制削减杂交技术发现差异片段并应用PCR验证。结果发现了5个在不同生物型鼠疫菌问存在差异的DNA片段，其中一个383bp的片段在来自天山山地灰旱獭、长尾黄鼠鼠疫自然疫源地的30株鼠疫菌全部阳性，而来自其它鼠疫自然疫源地的菌株全部阴性，5株假结核耶尔森菌中有2株(生物Ⅰ型和Ⅱ型)阳性。结论该383bp片段为天山山地灰旱獭、长尾黄鼠鼠疫自然疫源地的鼠疫菌所特有，此疫源地的菌株可能是我国较古老的鼠疫菌。     

我国鼠疫菌毒力因子的比较与分析

目的 研究自不同生态型和不同鼠疫自然疫源地分离的鼠疫菌4种毒力因子的性状特征。方法 常璺方法检查鼠疫菌毒力因子性状并比较在不同疫源地之间、不同生态型之间的差异。结果 1326株鼠疫菌中仅1株缺失FI、6株缺失PstI,Pgm和WW阳性分别为92.99%、76.47%。结论 自我国不同疫源地、平淡同生态型和不同年代分离的野生型鼠疫菌绝大多数能产生FI和PstI,且不同生态型和不同疫源地分离的菌株这两种毒力因子无明显差别,性状稳定,VW^-和Pgm^-菌株与生态型及疫源地有一定的关系。经长期人工培养传代后。4种毒力因子相比,VW因子较易丧失,该毒力因子具有更不稳定特点。     

云南、福建和贵州省鼠疫耶尔森菌基因分型研究

云南省位于我国西南边陲，存在滇西山地齐氏姬鼠大绒鼠鼠疫自然疫源地（野鼠鼠疫疫源地）和滇西山地闽广沿海居民区黄胸鼠鼠疫自然疫源地（家鼠鼠疫疫源地），除了剑川地区属于野鼠鼠疫疫源地外，云南省的西北部疫区均属于家鼠鼠疫疫源地。福建省位于我国东南沿海，其境内的鼠疫自然疫源地也属于家鼠鼠疫疫源地。贵州省兴义市位于云南和广西省交界处，也属于家鼠鼠疫疫源地。为了比较家鼠及野鼠疫源地鼠疫耶尔森菌（以下简称鼠疫菌）基因组成的差别，采用PCR技术对分离自三省的69株鼠疫菌进行了基因分型研究。     

西藏地区鼠疫菌生物学特性的分析

目的：通过对西藏地区29个县（市），不同宿主分离的116株鼠疫菌生化，毒力，毒力因子，质粒及外膜蛋白的分析，了解该疫源地内鼠疫病原体间的群落关系及遗传变异的规律性。方法：各项检查均按常规方法进行。结果：目前该地区仅有岗底斯山型和青藏高原型两种生态型菌株，二者分别占据一定的地理区域，以念青唐古拉山脉为天然屏障，从藏北地区分离的菌株为青藏高原型，藏南地区及其西南部所分离的菌株均为岗底斯山型。结论：西藏地区是以喜玛拉雅旱獭为主要宿主的鼠疫自然疫源地，就其鼠疫菌生物学特性分析表明，藏北高原疫源地可能是青藏高原喜玛拉雅旱獭疫源地的延伸，而藏南谷地可能是由于有天然屏障的存在，形成了自己特定的地理环境，从而表现为相对独立的一块鼠疫自然疫源地。     

Identification of different regions among strains of Yersinia pestis by suppression subtractive hybridization

Yersinia pestis, the causative agent of bubonic and pneumonic plague, has been classified into four biovars: Antiqua, Mediaevalis, Orientalis and Microtus. Although the entire genome sequences of three Y. pestis strains, CO92, KIM and 91001, of biovar Orientalis, Mediaevalis and Microtus, respectively, have been decoded, the genome sequence of the biovar Antiqua strain is unknown. In an initial effort to find Antiqua-specific sequences, suppression subtractive hybridization (SSH) was performed and four different regions (DFRs) were identified. Among the four DFRs, only DFR4 was specific to the tester (strain 49006, biovar Antiqua). PCR demonstrated that DFR4 was present only in 57 of 60 Antiqua strains from the Marmota baibacina-Spermophilus undulates plague focus in the Tianshan Mountains (focus B) and in three strains of Y. pseudotuberculosis (serotypes I and II), showing that not all Antiqua strains had DFR4. Five DFR profiles were identified based on the presence or absence of these four DFRs in 636 strains of Y. pestis from 10 plague foci in China.     

Identification of a Yersinia pestis-specific DNA probe with potential for use in plague surveillance.

A 900-base-pair DNA fragment derived from a 9.5-kilobase plasmid in Yersinia pestis hybridized specifically with Y. pestis DNA. We demonstrated the feasibility of using this DNA fragment to detect plague bacilli directly in fleas, suggesting that this Y. pestis-specific DNA probe may be used for plague surveillance in the field. Additional applications for this DNA probe may include plague diagnosis and pathogenesis research.     

致病性耶尔森氏菌PCR扩增多态性的研究

目的为了解不同来源的鼠疫耶尔森氏菌和不同血清型的小肠结肠炎耶尔森氏菌及假结核耶尔森氏菌（ＰＴＢ３）的遗传学差异。方法使用随机引物扩增多态ＤＮＡ（ＲＡＰＤ）技术。结果鼠疫耶尔森氏菌和假结核耶尔森氏菌的扩增主带型相似，而与小肠结肠炎耶尔森氏菌的差异较大；不同来源的鼠疫耶尔森氏菌株ＲＡＰＤ图谱亦有细微差别。小肠结肠炎耶尔森氏菌不同血清型的菌株以及同一血清型不同来源株的ＲＡＰＤ亦有较大差异。这为耶尔森氏菌更进一步的分型提供了一种新方法。此外，还根据小肠结肠炎耶尔森氏菌肠毒素基因设计了一对引物，将７个血清型６６株小肠结肠炎耶尔氏菌分成两组，一组的扩增为预期的２８９ｂｐ片段，另一组为约２００ｂｐ的片段。结论实验表明，鼠疫菌和假结核菌可以通过ＲＡＰＤ和其它生物学技术相结合加以区分。使用ＲＡＰＤ技术可对同一血清型不同来源的小肠结肠炎耶尔森氏菌进行更进一步分型。上述方法可用于分子流行病学调查。     

Identifying sources of human exposure to plague

Yersinia pestis, the etiologic agent of plague, has shaped the course of human history, killing millions of people in three major pandemics. This bacterium is still endemic in parts of Asia, Africa, and the Americas, where it poses a natural disease threat to human populations. Y. pestis has also recently received attention as a possible bioterrorism agent. Thus, rapid methods to distinguish between bioterrorism and naturally occurring plague infections are of major importance. Our study is the first to demonstrate that variable-number tandem repeats (VNTRs) in the Y. pestis genome can link human case isolates to those obtained from suspected environmental sources of infection. We demonstrate the valuable utility of VNTR markers in epidemiological investigations of naturally occurring plague and the forensic analysis of possible bioterrorism events.     

Efficient tracing of global isolates of Yersinia pestis by restriction fragment length polymorphism analysis using three insertion sequences as probes

Yersinia pestis is the etiologic agent of plague, a disease that is transmitted from rodent to rodent and from rodent to humans by fleabites. Multiple copies of three insertion sequences (IS100, IS285, and IS1541) are scattered over the Y. pestis genome. The genomic instability generated by these insertion sequences (IS) creates a polymorphism of the hybridizing restriction fragments (restriction fragment length polymorphism [RFLP]) which can be used to subtype this relatively clonal species. The aim of this work was to evaluate and compare the potential of the three IS-RFLP techniques, individually or in combination, to define clusters of strains according to their focus of origin. The analysis of 61 Y. pestis isolates of worldwide origin indicated that no satisfactory strain clustering was observed with each IS-RFLP used individually. In contrast, the combination of the three IS-RFLP data (3IS-RFLP) resulted in both an efficient strain discrimination (D = 0.999) and a robust clustering of the isolates according to their biovar and geographical origin. This geographical clustering was observed even within the Orientalis group, although these strains had only a short period of time (one century) to diverge from the original clone that spread globally. Therefore, 3IS-RFLP is a technique that may be useful for addressing epidemiological problems and forensic issues. When plague reemerges after several decades of silence in a quiescent focus, it may help in determining whether the disease was reimported or reactivated. It may also be of value to identify the origin of a strain when plague cases appear in a previously plague-free region. Finally, this technique could be useful for the tracing of a Y. pestis isolate that has been used as a biological terrorism threat.     

Invasin production by Yersinia pestis is abolished by insertion of an IS200-like element within the inv gene.

The two enteropathogens Yersinia pseudotuberculosis and Yersinia enterocolitica penetrate eukaryotic cells in vitro through invasin, a surface-exposed protein. In contrast, Yersinia pestis, the causative agent of plague, is unable to enter mammalian cell lines, although the inv gene is present on its chromosome. Although 99.3% identical to the inv gene of Y. pseudotuberculosis, the Y. pestis inv gene was disrupted in its central region by a 708-bp IS200-like element. Multiple copies of this insertion sequence element were found within the genome of the plague bacillus.     

Polymorphisms in the lcrV gene of Yersinia enterocolitica and their effect on plague protective immunity

Current efforts to develop plague vaccines focus on LcrV, a polypeptide that resides at the tip of type III secretion needles. LcrV-specific antibodies block Yersinia pestis type III injection of Yop effectors into host immune cells, thereby enabling phagocytes to kill the invading pathogen. Earlier work reported that antibodies against Y. pestis LcrV cannot block type III injection by Yersinia enterocolitica strains and suggested that lcrV polymorphisms may provide for escape from LcrV-mediated plague immunity. We show here that polyclonal or monoclonal antibodies raised against Y. pestis KIM D27 LcrV (LcrV(D27)) bind LcrV from Y. enterocolitica O:9 strain W22703 (LcrV(W22703)) or O:8 strain WA-314 (LcrV(WA-314)) but are otherwise unable to block type III injection by Y. enterocolitica strains. Replacing the lcrV gene on the pCD1 virulence plasmid of Y. pestis KIM D27 with either lcrV(W22703) or lcrV(WA-314) does not affect the ability of plague bacteria to secrete proteins via the type III pathway, to inject Yops into macrophages, or to cause lethal plague infections in mice. LcrV(D27)-specific antibodies blocked type III injection by Y. pestis expressing lcrV(W22703) or lcrV(WA-314) and protected mice against intravenous lethal plague challenge with these strains. Thus, although antibodies raised against LcrV(D27) are unable to block the type III injection of Y. enterocolitica strains, expression of lcrV(W22703) or lcrV(WA-314) in Y. pestis did not allow these strains to escape LcrV-mediated plague protective immunity in the intravenous challenge model.