微小隐孢子虫CRIP基因克隆与分析

目的 比对分析微小隐孢子虫南京(NJ)株亲环素-RNA相互作用蛋白(CRIP)与其他隐孢子虫株CRIP基因序列的差异。方法 根据GenBank微小隐孢子虫Iowa Ⅱ株CRIP基因序列设计并合成2对引物,应用巢式聚合酶链反应(PCR)技术从微小隐孢子虫NJ株基因组DNA中扩增CRIP基因,并将其克隆到pMD18-T载体上,将重组质粒pMD18-T-CpCRIP进行PCR和双酶切鉴定后测序,应用生物信息学方法分析微小隐孢子虫NJ株CRIP基因与其他种属的CRIP基因序列同源性。结果 巢式PCR扩增获得的特异性CRIP基因序列,经PCR及双酶切鉴定确为pMD18-T-CpCRIP重组质粒;测序结果显示,该序列有119 bp,微小隐孢子虫NJ株CRIP基因全长为909 bp,编码302个氨基酸;测序结果和同源性分析显示,中国微小隐孢子虫NJ株CRIP基因序列与国外的微小隐孢子虫Iowa II株同源性为98%;该隐孢子虫NJ株CRIP基因序列获GenBank登录号JQ396883。结论 微小隐孢子虫NJ株CRIP基因与其他微小隐孢子虫株存在基因变异。     

微小隐孢子虫20K亲环蛋白基因克隆及分析

目的克隆微小隐孢子虫(Cp)南京株(NJ)的20K 亲环蛋白(CyP)基因,并对其核苷酸和氨基酸序列进行分析。方法采用昆明种小鼠建立微小隐孢子虫NJ株感染模型,根据微小隐孢子虫Iowa II株20K CyP 基因序列设计合成2对引物,应用巢式PCR技术从微小隐孢子虫NJ株基因组DNA 中扩增20K CyP基因,并将其克隆到pMD18-T载体上,将阳性克隆重组质粒进行菌落PCR及双酶切鉴定;应用生物信息学方法分析微小隐孢子虫NJ株20K CyP基因与其他虫株核苷酸和氨基酸序列差异,并分析该基因蛋白结构域。结果巢式PCR 扩增得到特异的20K CyP基因,经PCR及双酶切鉴定获得了正确的pMD18-T-20K CyP重组质粒;测序结果显示,微小隐孢子虫NJ株20K CyP 基因全长519 bp,编码173个氨基酸,该基因已登录GenBank,登录号为JQ284431;氨基酸序列分析表明,微小隐孢子虫NJ株与Iowa II株20K CyP基因编码的氨基酸序列具有100%同源性;对20K Cyp基因进行蛋白结构域分析,显示该基因序列所编码的蛋白具有特异性类亲环蛋白A、B、H的肽脯氨酰顺反异构酶(PPIase)区域,该区域与人的亲环蛋白A、B、H具有相似性。结论成功克隆微小隐孢子虫NJ株20K CyP基因,该基因具有高度保守性。     

日本血吸虫pcDNA3．1．（＋）-SjPGK重组质粒的构建及鉴定

目的 构建日本血吸虫中国大陆株磷酸甘油酸激酶基因片段(SiPGK)的真核表达重组质粒，寻找新的预防日本血吸虫病的候选疫苗分子。方法 采用逆转录一聚合酶链反应(RT-PCR)技术，从日本血吸虫总RNA中体外扩增SPGK基因片段；克隆人pMD18-T载体中，然后挑取阳性克隆经双酶切分析、PCR鉴定；亚克隆人真核表达载体pcDNA3．1( )中，阳性克隆经鉴定后进行脱氧核糖核酸序列测定；运用Blast程序，将测序结果及其推导的编码氨基酸序列与NCBI数据库在核苷酸水平和氨基酸水平进行同源性比较。结果 RT-PCR特异性扩增出一条长约830bp大小的条带；重组质粒pMD18-T-SPGK和pcDNA3．1( )-SPGK经双酶切和以质粒为模板进行PCR扩增，均可获得一条与RT-PCR产物一致的DNA片段；脱氧核糖核酸序列测定和分析结果表明：SjPGK基因片段长为830bp，与SmPGK的核苷酸同源性为85％，分值为672；氨基酸同源性为94％，分值为473。结论 成功地构建pcDNA3．1( )-SiPGK重组质粒，为构建其核酸癌苗提供了条件。     

周期型马来丝虫半胱氨酸蛋白酶基因的扩增、克隆及序列分析

[目的]克隆周期型马来丝虫半胱氨酸蛋白酶（cysteine protease of periodic Brugia malayi,BmCP）基因到原核载体中,测定其序列,为进一步的研究奠定基础.[方法]从周期型马来丝虫虫体中抽提总RNA,以mRNA为模板,采用RT-PCR法体外扩增出BmCP基因序列,扩增产物经初步鉴定后将其克隆入pMD18-T载体,转化大肠杆菌（E. coli）DH5α,筛选阳性克隆,进行双酶切及PCR扩增签定,获得阳性重组质粒pMD18-T-BmCP,经测序验证,并进行同源性比较.[结果]RT-PCR扩增出一条约1 201 bp大小的特异性条带,重组质粒双酶切和以质粒为模板的PCR结果与预期相符,DNA序列分析与GeneBank已知的基因序列同源性为99%.[结论]成功构建了周期型马来丝虫半胱氨酸蛋白酶重组质粒pMD18-T克隆载体,为进一步研究该基因的功能提供了条件.     

AIDS患者合并感染耶氏肺孢子虫的巢式PCR检测及ITS基因的克隆测序

目的 探讨ITS巢式PCR检测AIDS患者合并耶氏肺孢子虫感染的应用价值并对ITS1-5.8S rDNA-ITS2基因进行克隆测序.方法 收集AIDS患者痰液标本,用二硫苏糖醇(DTT)消化处理后进行六亚甲基四胺银(CMS)染色镜检;提取肺孢子虫DNA后进行巢式PCR扩增,选取GMS染色和PCR同时阳性的112号和仅PCR阳性的185、200号病例的PCR产物进行TA克隆、测序,然后用Blastn程序和DNANAN软件对所测序列进行同源性比较和序列间比对,并和GenBank登录的耶氏肺孢子虫ITS1-5.KS rDNA-ITS2序列进行比较分析.结果 用ITS巢式PCR法检测AIDS患者99例,耶氏肺孢子虫DNA阳性43例,阳性率为43.4%(43/99),用GMS染色法检测,阳性率为4.04%(4/99),两者比较,有非常显著性差异(P<0.01).TA克隆112、185、200号病例的耶氏肺孢子虫ITS1-5.8S rDNA-ITS2基因序列长度分别为523bp、515bp、51lbp,三者之间的基因同源性为95%～97%,与GenBank登录的耶氏肺孢子虫(U07220)、(U07221)、(U07222)和(U07226)的ITS1-5.8S rDNA-ITS2基因的同源性为95%～98%,其变异位点多在ITS1和ITS2基因片段.结论 ITS巢式PCR法检测耶氏肺孢子虫敏感性明显高于GMS染色法.ITS巢式PCR法可作为肺孢子虫肺炎早期诊断方法,尤其适用无创性标本的检测,CMS染色法对无创性标本痰液的检测敏感性低,在临床上意义不大;成功获取广西株耶氏肺孢子虫ITS1-5.8S rDNA-ITS2的基因序列,与GenBank登录的外国株耶氏肺孢子虫基因序列高度同源,其中5.8S rDNA高度保守,ITS1和ITS2基因变异较大.     

幽门螺杆菌分离株iceA基因克隆及序列分析

目的 克隆幽门螺杆菌中国郑州市慢性萎缩性胃炎患者分离株MEL-Hp27iceA基因,测序后对其进行序列分析。方法 根据iceA基因上下游基因序列设计引物,PCR扩增iceA基因,并将其连接至pMD19-T载体,测序后采用相关数据库和生物信息学软件对基因序列进行分析。结果 成功克隆幽门螺杆菌Hp27菌株iceA基因序列,扩增产物大小约为790 bp;重组质粒pMD19-T-iceA单酶切产生3 820 bp片段,双酶切产生3 000和820 bp的2个片段;Hp27iceA基因与大多数美国来源菌株同源性>85%,与日本、印度等地区来源菌株同源性<70%。序列分析结果表明,所克隆到的基因为iceA2亚型,与美国株Alaska strain 219、Alaska strain 213关系最近,同源性分别为87%和95%,与芬兰株Finland strain 9496等菌株存在聚类关系,同源性88%～93%,与CR9等其他菌株距离较远。结论 成功克隆幽门螺杆菌Hp27菌株iceA基因序列;不同地区幽门螺杆菌分离株的iceA基因间存在着一定差异。     

猪链球菌2型浙江嘉兴株毒力基因序列分析

目的 猪链球菌2型(SS2)浙江嘉兴ZJJX2008分离株毒力基因序列测定与分析。方法 提取菌株DNA,应用聚合酶链反应(PCR)扩增菌株Cps2J和EF基因全片段,克隆入质粒载体,纯化后测定序列,并与国内外其他分离株基因进行比较。结果 Cps2J、EF基因完整开放阅读框(ORF)分别为999,2532bp,各自编码333,843个氨基酸,ZJJX2008分离株Cps2J、EF基因与国内外SS2菌株核苷酸同源性分别为99.1%～100%和99.8%～99.9%,氨基酸同源性分别为99.2%～99.7%和99.3%～99.5%;ZJJX2008分离株Cps2J基因与猪链球菌1型荷兰分离株6555核苷酸和氨基酸同源性只有66.7%和51.8%。结论 ZJJX2008分离株为猪链球菌2型菌株,Cps2J、EF基因与国内外其他SS2分离株比较序列非常保守,变异不大。     

新疆博乐地区大沙土鼠感染恙虫病东方体基因分型与序列分析

目的 鉴定新疆博乐地区恙虫病东方体分离株的基因型别,分析其核苷酸序列.方法 应用巢式PCR(nPCR)对新疆博乐地区采集的鼠标本Ot-Sta56KDa基因片段进行检测,PCR扩增产物纯化后测序,进行序列分析.结果 博乐地区艾比湖滩涂地优势鼠种为大沙土鼠;在大沙土鼠脾总DNA用群引物扩增出481～507bp的目的 片段;经相应型引物扩增出了目的 片段,序列同源性显示,核苷酸序列与Karp、ISS-11、Taiwan的核苷酸序列的同源性为97%,与Kanda的核苷酸序列同源性为92%.系统发生树表明,分离株与Karp株亲缘关系较近.结论 在新疆地区首次从大沙土鼠中分离并扩增到恙虫病东方体基因片段,与Karp株型有较近的亲缘关系.     

新疆博乐地区大沙土鼠感染恙虫病东方体基因分型与序列分析

目的鉴定新疆博乐地区恙虫病东方体分离株的基因型别,分析其核苷酸序列。方法应用巢式PCR（nPCR）对新疆博乐地区采集的鼠标本Ot-Sta56KDa基因片段进行检测,PCR扩增产物纯化后测序,进行序列分析。结果博乐地区艾比湖滩涂地优势鼠种为大沙土鼠;在大沙土鼠脾总DNA用群引物扩增出481507bp的目的片段;经相应型引物扩增出了目的片段,序列同源性显示,核苷酸序列与KarpI、SS-11、Taiwan的核苷酸序列的同源性为97%,与Kanda的核苷酸序列同源性为92%。系统发生树表明,分离株与Karp株亲缘关系较近。结论在新疆地区首次从大沙土鼠中分离并扩增到恙虫病东方体基因片段,与Karp株型有较近的亲缘关系。     

一种新型β-内酰胺酶OKP-B-13的发现

目的鉴定一种新型超广谱β-内酰胺酶肺炎克雷伯菌的基因亚型并分析其耐药性。方法分析11种抗菌药物对该菌株的最低抑菌浓度(MIC),并以碱裂解法抽提菌株的质粒DNA,应用聚合酶链反应(PCR)扩增产ESBLs株质粒的TEM、SHV、CTX基因,对其扩增产物进行DNA序列分析。结果TEM基因和CTX-M基因的PCR扩增结果均显示为阴性,SHV基因的PCR扩增获得862 bp产物;DNA测序未能在GenBank数据库查询到与之相一致的核苷酸序列,该基因编码的氨基酸序列与OKP型β-内酰胺酶为最相近,存在4~18个氨基酸差异,与SHV-1同源性为90%;此新型β-内胺酶被命名为OKP-B-13(GenBank注册号AY825330)。结论发现了一种新型的产ESBLs肺炎克雷伯菌β-内酰胺酶-OKP-B-13,其酶特性有待进一步研究。     

Comparative genome analysis of two Cryptosporidium parvum isolates with different host range

Parasites of the genus Cryptosporidium infect the intestinal and gastric epithelium of different vertebrate species. Some of the many Cryptosporidium species described to date differ with respect to host range; whereas some species' host range appears to be narrow, others have been isolated from taxonomically unrelated vertebrates. To begin to investigate the genetic basis of Cryptosporidium host specificity, the genome of a Cryptosporidium parvum isolate belonging to a sub-specific group found exclusively in humans was sequenced and compared to the reference C. parvum genome representative of the zoonotic group. Over 12,000 single-nucleotide polymorphisms (SNPs), or 1.4 SNP per kilobase, were identified. The genome distribution of SNPs was highly heterogeneous, but non-synonymous and silent SNPs were similarly distributed. On many chromosomes, the most highly divergent regions were located near the ends. Genes in the most diverged regions were almost twice as large as the genome-wide average. Transporters, and ABC transporters in particular, were over-represented among these genes, as were proteins with predicted signal peptide. Possibly reflecting the presence of regulatory sequences, the distribution of intergenic SNPs differed according to the function of the downstream open reading frame. A 3-way comparison of the newly sequenced anthroponotic C. parvum, the reference zoonotic C. parvum and the human parasite Cryptosporidium hominis identified genetic loci where the anthroponotic C. parvum sequence is more similar to C. hominis than to the zoonotic C. parvum reference. Because C. hominis and anthroponotic C. parvum share a similar host range, this unexpected observation suggests that proteins encoded by these genes may influence the host range.     

Giardia duodenalis genotypes and Cryptosporidium species in humans and domestic animals in Côte d'Ivoire: occurrence and evidence for environmental contamination

Giardia duodenalis genotypes and Cryptosporidium species were studied in humans and free-ranging animals living in closed enclaves in C?te d'Ivoire. Three hundred and seven stool samples were tested from humans, and 47 from freely roaming domestic animals (dogs, goats, ducks, chickens). Molecular characterization of the isolates was performed by sequence analysis of a portion of the SSU-rDNA for Giardia and the COWP gene for Cryptosporidium, and a β-giardin SYBR-green real-time PCR was also used to confirm the assignment of Giardia isolates to Assemblages. In humans, genotyping of Giardia assigned many of the sequences (43/56 by the SSU-rDNA gene, and 36/61 by the β-giardin gene) to Assemblage B. The animal species harboured only zoonotic Assemblages A and B, except for dogs, in which host specific Assemblages C and D were also detected. Cryptosporidium meleagridis, C. parvum and C. hominis were detected in humans, while among the animals only chickens were found positive for oocysts, identified as C. meleagridis and C. parvum. The results provide further evidence about the role of free-ranging domestic animals living closely with humans in the environmental dissemination and potential transmission of these anthropozoonotic pathogens to humans.     

Tracking Cryptosporidium parvum by sequence analysis of small double-stranded RNA

We sequenced a 173-nucleotide fragment of the small double-stranded viruslike RNA of Cryptosporidium parvum isolates from 23 calves and 38 humans. Sequence diversity was detected at 17 sites. Isolates from the same outbreak had identical double-stranded RNA sequences, suggesting that this technique may be useful for tracking Cryptosporidium infection sources.     

Differentiating human from animal isolates of Cryptosporidium parvum.

We analyzed 92 Cryptosporidium parvum isolates from humans and animals by a polymerase chain reaction/restriction fragment length polymorphism method based on the thrombospondin-related anonymous protein 2 gene sequence. Used as a molecular marker, this method can differentiate between the two genotypes of C. parvum and elucidate the transmission of infection to humans.     

两种机会性寄生原虫——微小隐孢子虫和蓝氏贾第鞭毛虫基因检测方法的建立

目的建立两种机会性寄生原虫——微小隐孢子虫和蓝氏贾第鞭毛虫（贾第虫）基因检测方法。方法从微小隐孢子虫和蓝氏贾第鞭毛虫感染者粪便标本内分离纯化卵囊和包囊，提取基因组DNA。根据微小隐孢子虫18S rRNA基因和贾第虫磷酸丙糖异构酶（tim）基因各设计或合成两对特异性引物，采用PCR技术分别对从卵囊和包囊提取的和6种对照DNA样本（日本血吸虫、刚地弓形虫、溶组织内阿米巴、旋毛虫和阴道毛滴虫以及人体血细胞DNA等），以及此二种虫相互间的DNA样本进行检测，以确定该法的特异性和敏感性。方法建立后，取艾滋病患者粪便标本对之进行检测。结果从微小隐孢子虫和贾第虫的DNA样本中分别扩增出各自相应基因的500bp和683bp长度的片段；最少可检测出20pg隐孢子虫和0．4pg贾第虫DNA；几种对照DNA样本均不发生交叉反应；受检的30例艾滋病患者粪便标本中，7例显示微小隐孢子虫阳性，未检出贾第虫。结论建立的基因检测方法，对微小隐孢子虫和贾第虫的检测具有高度的特异性和敏感性，可用于临床艾滋病合并感染的早期诊断和人群流行病学筛查。     

Asymptomatic cryptosporidiosis in Zambian dairy farm workers and their household members

The prevalence of Cryptosporidium and the possibility of zoonotic transmission on dairy farms were examined. Eighteen cases of cryptosporidiosis (prevalence 6%) were identified in 82 farm workers and 207 household members. Furthermore, 70 (34%) of 207 calf samples were positive. Based on the 70kDa heat shock protein and the 18S rDNA gene, Cryptosporidium parvum was identified in 75% of the positive farm workers and in 60% of the household members. Of the positive calves, 62% were infected with C. parvum, indicating a possible zoonotic transmission on these farms.     

深圳市地表水贾第鞭毛虫和隐孢子虫污染状况的调查

目的:了解深圳市地表水贾第鞭毛虫和隐孢子虫的污染状况,为饮用水水质卫生、安全供水提供科学依据。方法:采集以水库水为源水的8家村镇水厂水样及3家污水处理厂排出水,共21份样品,应用美国环保局(EPA)的标准检测方法,对水样作抽滤、淘洗、磁分离、染色鉴定的处理,检测贾第鞭毛虫和隐孢子虫卵囊含量。结果:深圳市8家村镇级水厂有6家源水检出贾第鞭毛虫包囊,1家水厂的源水检出隐孢子虫卵囊,3家污水处理厂中有2家污水处理后排出水检出贾第鞭毛虫和隐孢子虫卵囊。结论:深圳市地表水可检出致病性原虫,源水受到污染的可能性存在,要保证水质卫生,做到优质安全供水,必须加强卫生管理。     

The prevalence of Cryptosporidium species and subtypes in human faecal samples in Ireland

Cryptosporidium is an important cause of diarrhoeal disease worldwide and, as several recent waterborne outbreaks have shown, poses a significant threat to public health in Ireland. We identified the Cryptosporidium spp. in 199 positive human stool samples by PCR-RFLP of the 18S rRNA and COWP gene loci. Subspecies were identified in 104 samples by sequence analysis of the 60 kDa glycoprotein (gp60) gene fragment. Overall C. parvum was identified in 80%, and C. hominis in 20% of cases. No other Cryptosporidium spp. were detected. C. parvum was by far the most common species in the rural, more sparsely populated west of Ireland and exhibited a pronounced spring peak coincident with a peak in the national cryptosporidiosis incidence rate. Our data indicated a trend towards higher proportions of C. hominis in older age groups. Ninety-nine per cent of all subtyped C. parvum isolates belonged to allele family IIa, of which allele IIaA18G3R1 was by far the most common (63%). According to a recent study by Thompson and colleagues [Parasitology Research (2007), 100, 619-624] this allele is also the most common in Irish cattle. Subtyping of the C. hominis isolates indicated that they belonged to a geographically widely distributed allele (IbA10G2) known to have caused several water- and foodborne outbreaks around the world. The predominance of C. parvum, its geographic and seasonal distribution and the IIaA18G3R1 subtype underlines the importance of zoonotic Cryptosporidium transmission in Ireland.