苏云金杆菌cryIVD基因的克隆及序列分析

目的　克隆苏云金杆菌 ( B.t.i) cry IVD基因并测定其序列。　方法　根据 B.t.i cry IVD已知序列 ,设计合成 1对引物 ,应用 PCR技术扩增 cry IVD基因 ,克隆入 p UC18载体 ,阳性克隆的重组质粒经酶切、电泳鉴定后进行序列测定。　结果　 PCR扩增得到特异的 2 .0 kb基因片段。重组质粒经酶切后得到预期大小的基因片段。序列分析证明目的基因被完整且正向克隆。　结论　 B.t.i cry IVD基因被成功克隆。     

小肠结肠炎耶氏菌毒力相关基因探针的制备

本研究采用分子生物学方法从0:8型小肠结肠炎耶氏菌(Ye菌)所携带的毒力大质粒上分离、纯化了与Sereny试验相关的毒力基因2.8kb片段,经半抗原标记作为探针。菌落原位杂交结果证明2.8kb探针可与含表达VW抗原质粒的不同型Ye菌和假结核杆菌特异性杂交,与宋氏痢疾、EIEC和大肠杆菌无交叉反应。表明2.8kb探针有高度的特异性,且它与痢疾杆菌和EIEC的Sereny反应无关,在检测耶氏菌毒株方面将成为一个很有发展前景的DNA探针     

大鼠天然抗体相关的弓形虫抗原基因的免疫筛选与克隆

目的　研究大鼠对弓形虫感染的天然抗性分子 ,为弓形虫病疫苗的研制提供新的抗原分子。方法　用正常大鼠血清作为探针筛选弓形虫速殖子cDNA文库 ,对阳性克隆的插入片段分别进行PCR扩增及DNA序列测定。结果　从cDNA文库 2× 10 5个噬菌斑中筛选出 5个阳性克隆 ,其插入片段大小分别为 0 5 5～ 1 8kb。对P1、P4、P6和P8四个克隆进行测序 ,将所得序列查询基因序 ,结果显示 :P8与弓形虫棒状体蛋白 2 (ROP2 )基因相同。P4为弓形虫的新基因序列 (GenBank中的登录号为AY34916 2 ) ,命名为T .gP4。T .g -P4编码 96个氨基酸的跨膜蛋白。PROSCAN分析显示T .g -P4含有 4个蛋白激酶C磷酸化位点 ,3个N -肉豆酸酰化位点 ,1个核糖体蛋白L2 9信号。P1和P6为新基因片段。阳性克隆的分子鉴定正在进行中。结论　阳性克隆的筛选和鉴定为抗弓形虫病疫苗的研制奠定基础。     

人单核细胞泡沫化敏感候选基因的筛选

为克隆调控单核细胞源性泡沫细胞形成的相关基因 ,采用抑制消减杂交法筛选U937细胞经氧化型低密度脂蛋白温育形成泡沫细胞后差异表达的基因。经过正向、反向两轮消减杂交和巢式聚合酶链反应扩增 ,获得了富集的差异表达的cDNA片段 ,即表达序列标签 ,克隆化后挑选经鉴定含有插入片段的质粒测序。经Genbank数据库进行同源比较 ,获得 2 0余个差异表达的EST ,其中 2个克隆FRG4和FRG1 4只有片段同源序列而无全长同源序列 ,提示可能来自新基因。Genbank登录号为 :FRG4(BI 50 2 586)和FRG1 4 (BI 50 2 587)。     

恙虫病东方体47kDa蛋白基因部分片段的克隆与表达

目的　表达恙虫病东方体 (Orientiatsutsugamushi,Ot) 4 7kDa保护性抗原蛋白。 方法　采用PCR方法 ,从OtKarp株基因组DNA中扩增出 4 7kDa蛋白基因片段 ,鉴定后将该片段克隆于原核表达载体 pBV2 2 0 ,构建成重组质粒pBV -4 7。用该重组质粒转化E coli,转化子在 4 2℃诱导表达并对其鉴定。结果　 (1)获得长约 14 30bp的PCR片段 ,序列分析结果与已知 4 7kDa基因序列相同 ;(2 )SDS -PAGE检测表达产物 ,在相对分子量 4 0× 10 3 处有表达带 ;(3)经薄层扫描分析 ,目的蛋白占全菌蛋白的 19% ;(4)免疫印迹实验证明其具有免疫反应性。结论　获得了 4 7kDa基因片段 ,并在大肠杆菌中实现了表达 ,表达产物具有免疫反应性。     

问号澳洲型钩端螺旋体复合抗原基因ompL_1/flaB_2表达质粒的构建

目的　为增强澳洲型钩端螺旋体 (简称澳洲型钩体 ) 6 0 7株抗原的免疫原性 ,而构建其外膜蛋白抗原基因ompL1和内鞭毛抗原基因flaB2 的复合抗原基因重组质粒。方法　通过聚合酶链反应扩增ompL1及flaB2 ,将其分别克隆到pcD NA3 1/Myc-His(+)载体T7启动子下游 ,进行序列测定分析 ,在此基础上将ompL1及flaB2 同时克隆至表达载体 pcD NA3 1/Myc -His(+) ,构建成A - pcLMF1复合抗原基因表达质粒。结果　澳洲型钩体 6 0 7株的ompL1及flaB2 与报道的其它株钩体的序列呈很高的同源性。澳洲型钩体重组质粒A -pcLMF1经酶切鉴定证实 :有一 1 8kb片段插入。结论　澳洲型钩体复合抗原基因ompL1/flaB2 融合表达质粒构建成功     

含有MS4A7基因启动子的荧光素酶报告基因质粒的构建及意义

目的构建含有人4次跨膜监视蛋白A（MS4A）基因启动子的萤火虫荧光素酶报告基因质粒。方法用PCR方法扩增获得含有人MS4A7基因启动子的DNA片段,将其连接至TA克隆质粒后转移至虫荧光素酶质粒pGL3-basic中,得到pGL3-MS4A7-Promoter重组质粒;经限制性内切酶酶切、PCR及测序鉴定得到确认;将该质粒转染进入HL-60细胞,并检测细胞中虫荧光素酶的活性。结果 pGL3-MS4A7-Promoter重组质粒插入片段和相邻序列正确,克隆的MS4A7基因片段有启动子活性。结论成功构建了pGL3-MS4A7-Promoter报告基因质粒,为进一步研究MS4A7基因的表达调控奠定了基础。     

恶性疟原虫特异的基因克隆

本文用鸟枪法将恶性疟原虫基因组 DNA 片段克隆至载体 pBR_(322)质粒中,利用抗性遗传标志和琼脂糖凝胶电泳筛选重组克隆,克隆 pBF_8,pBF_(13),pBF_(23),pBF_(24)用 HindⅢ酶解后,均显示单一插入片段,分子大小分别为1.8,2.3,0.94和6.0kb。经 Southern Blot 和 Dot Blot 分析表明,克隆 pBF_(13)对恶性疟原虫基因组 DNA 特异,与人 DNA 无交叉性杂交,可用作诊断用探针。     

大鼠抗感染血清筛选日本血吸虫成虫cDNA文库

目的　探讨大鼠抗日本血吸虫 (Schistosomajaponicum ,Sj)感染的分子机制 ,为血吸虫病疫苗的研制提供新的抗原分子。方法　用Sj感染大鼠血清筛选Sj成虫cDNA文库 ,对阳性克隆cDNA插入片段进行PCR扩增及测序分析。 结果　对cDNA文库中约 3× 10 5个噬菌斑进行筛选 ,获 7个阳性克隆 ,其插入基因片段大小为 0 9kb～ 2 0kb。初步测序获 5个部分序列 ,其中R3与Sj线粒体基因明显同源 ;R5为新基因序列 ,命名为Sj-Cs2 (GenBank的登录号为AY0 36 5 80 ) ,经计算机分析该基因片段编码 2 0 6个氨基酸组成的跨膜蛋白 ,Sj-Cs2蛋白含有 3个蛋白激酶C磷酸化位点和 6个N -肉豆蔻酸化位点 ;其余序列亦为新基因片段 ,但无完整编码框。结论　筛选获得了与大鼠抗Sj感染有关的基因克隆 ,相关克隆cDNA全长的获取、新基因的结构与功能以及免疫学特性值得深入研究     

苏云金杆菌cryIVD基因的克隆及序列分析

目的 克隆苏云金杆菌（B.t.i)cryIVD基因并测定其序列。方法 根据B.t.i cryIVD已知序列，设计合成了1对引物，应用PCR技术扩增cryIVD基因，克隆入pUC18载体，阳性克隆的重组质粒经酶切，电泳鉴定后进行序列测定。结果 PCR扩增得到特异的2.0kb基因片段。重组质粒经酶切后得到预期大小的基因片段。序列分析证明目的基因被完整且正向克隆。结论 B.t.icryIVD基因被成功克隆。     

伤寒沙门菌耐药基因检测及定位

目的探讨伤寒沙门菌耐药基因的定位。方法３２Ｐ随机引物标记氯霉素耐药基因为探针，以Ｓｌｏｔｂｌｏｔ、Ｓｏｕｔｈｅｒｎｂｌｏｔ法检测，同时以氯霉素乙酰转移酶活性（ＣＡＴ）和药敏试验（ＭＩＣ）作为耐药标志。结果１６株伤寒菌中有１４株含９８６０００００大质粒。经杂交，其中７株质粒阳性；１株染色体阳性；３株质粒与染色体均为阳性。质粒杂交带位于４．３ｋｂ片段，染色体为５．２ｋｂ片段。结论伤寒菌耐氯霉素基因大部分位于９８６０００００大质粒上，少数位于染色体上或两者兼有     

Regulation of human erythropoietin gene induction by upstream flanking sequences in transgenic mice

Human erythropoietin (Epo) gene expression is inducible by hypoxia or anaemia in the kidney and liver. Previous transgenic mouse experiments have demonstrated that sequences required for Epo gene induction in the kidney reside in a 7.8 kb Bam HI fragment located 6 kb upstream of the gene. To sublocalize these sequences, we performed Desoxyribonuclease I (DNAse I) mapping studies using transgenic mice which carried this DNA fragment. These studies revealed a DNAse I hypersensitive site (DNAse I HS) located 4.6 kb from the upstream end of the 7.8 kb fragment in anaemic kidney and liver samples. Sequence analysis of the region encompassing the DNAse I HS revealed an element with remarkable homology to the 3' Epo gene hypoxia-inducible enhancer. This suggested the presence of an additional regulatory element that contributes to the control of hypoxia-inducible Epo gene expression in kidney and liver. We constructed transgenic mice containing the human Epo gene linked to either the 5 kb upstream or 2.5 kb downstream portion of the 7.8 kb fragment. Inducible expression was limited to the liver. Thus, neither fragment was alone sufficient to confer kidney inducible expression. These findings indicate that sequences more than 8.5 kb upstream of the Epo gene are required for kidney-specific induction. They suggest that either those sequences reside in an 0.3 kb Hind III fragment located between the 5 kb and the 2.5 kb fragments or that sequences in the 5 kb or 0.3 kb fragments must interact with sequences in the 2.5 kb fragment to allow Epo gene induction in the kidney.     

Cloning of a DNA fragment displaying restriction fragment length polymorphisms between the genomes of spontaneously hypertensive and Wistar-Kyoto rats

A 3 kilobase (kb) EcoRI fragment cloned from the genome of the spontaneously hypertensive rat (SHR) displayed restriction fragment length polymorphism (RFLP) compared with the genome of the Wistar-Kyoto rat (WKY) when total genomic Southern blot analysis was performed for two restriction enzymes, PstI and PvuII. Sequencing of the DNA fragment cloned from genomic SHR and WKY libraries revealed that this 3 kb EcoRI fragment harbours three point mutations. Two of them (C to T and A to T) are situated in the middle of the restriction sites for PstI and PvuII, thus disrupting the recognition sites for these enzymes in the SHR genome. Southern blot analysis using total complementary (c) DNA obtained from cDNA libraries of aortic smooth muscle cells from SHR and a whole WKY kidney, with this 3 kb EcoRI fragment as a probe, showed polymorphic bands suggesting that these point mutations are reflected in the sequences of messenger (m) RNA transcribed from the gene encoded in this 3 kb fragment. Detection of two bands by a Northern blot analysis for RNA from various SHR tissues indicates that this 3 kb fragment is actively transcribed in vivo.     

Epidemiology of infection by nontuberculous mycobacteria IX. Evidence for two DNA homology groups among small plasmids in Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum

A 12.9 kb plasmid, pVT2, from a clinical Mycobacterium avium isolate, MD1, was cloned and radiolabeled for use as a DNA probe to examine the relatedness of plasmids in M. avium complex. That probe hybridized with plasmids isolated from M. avium complex strains from the environment (7 of 16) and from non-acquired immunodeficiency syndrome (AIDS) (10 of 17) and AIDS (5 of 6) clinical isolates. The similarity of plasmids from the environment with those from patients supports the hypothesis that the environment is a source of human M. avium complex infection. More striking was the observation that pVT2 hybridized with every plasmid (13 of 13 clinical and 5 of 5 environmental isolates) of 13.5 kb or smaller. A second probe, consisting of a 15.3 kb plasmid (pLR7) from another clinical isolate of the M. avium complex, hybridized with plasmids of 15.3 to 25 kb from environmental and clinical (AIDS and non-AIDS) isolates. There was no hybridization between pVT2 and pLR7. Thus, these two probes define two different groups of small mycobacterial plasmids.     

正常人生长激素基因簇的结构分析及生长激素缺乏症的DNA诊断

利用DNA诊断技术,对正常人及16例侏儒症患者外周血白细胞DNA生长激素基因簇进行分析,在中国人种中首次发现2例患者(系同胞姐妹)为缺失包括hGH-N基因在内的7.1kbDNA片段的纯合子。患者的双亲、祖母及外祖母为携带缺失基因的杂合子,但表型正常;患者的祖父及外祖父为正常的纯合子,此疾病为常染色体隐性遗传病。其他14例患者均未发现hGH-N基因的缺失。对绒毛DNA分析结果表明与正常人白细胞DNA是一致的。这一方法在优生学上可作产前及婚前诊断,避免hGH-N基因缺失的纯合子出生。     

The modification and expression of 21-hydroxylase gene in normal human adrenal gland and adrenal cancer.

Genomic DNA and total RNA from three adrenal cancer tissues were analyzed by hybridization with human 21-hydroxylase gene. Southern blot analysis with restriction enzyme Eco RI revealed major fragments at 18, 13 and 9 kilobase (kb) in normal adrenal glands. In two of three adrenal cancers, however, the band at 18 kb was either absent or decreased and the 9 kb fragment showed an increase in its intensity. Normal liver, kidney and leucocytes has only 18 and 13 kb while lacking the 9 kb fragment. Using Taq I, Bam HI or Bgl II, we found no difference in restriction fragment patterns between adrenal cancer and normal tissues. Cleavage with Hpa II after digestion with Bgl II showed that significantly more DNA was digested into low-molecular weight fragments in adrenal cancer and the normal adrenal gland than those in other normal tissues. By Northern blot analysis, there was difference of signal intensity of hybridizing mRNA between the adrenal cancers and normal adrenal glands. These results suggest that the Eco RI site in the flanking region of the 21-hydroxylase gene may be modified in adrenal cancer tissue, and that inadequate 21-hydroxylase is present in some forms of adrenal cancers.     

Gene conversion in salt-losing congenital adrenal hyperplasia with absent complement C4B protein

Two of four siblings expressed the salt-losing form of congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH) and had identical human lymphocyte antigen (HLA) and complement C4 (fourth component of complement) types (HLA-A3,C4,B35,C4A3,C4BQO,DR1/A2,C-,B18,C4A3, C4BQO,DR6). The father and one unaffected sibling were heterozygous carriers of CAH, as determined by a 30-min iv ACTH stimulation test and HLA typing. In addition, the iv ACTH stimulation test revealed that the mother and the other unaffected sibling also carried an allele for an attenuated form of CAH. Restriction endonuclease digests of genomic DNA obtained from members of this family and from normal unrelated subjects were hybridized with cDNA probes encoding human 21-hydroxylase and C4. With the 21-hydroxylase probe, Southern blots prepared from control DNA samples revealed two major restriction fragments in each of four restriction endonuclease digests; TaqI produced major bands at 3.7 and 3.2 kilobases (kb), KpnI at 4.0 and 2.9 kb, EcoRI at 18 and 13 kb, and BglII at 15 and 12.5 kb. Southern blots prepared from DNA of the two patients lacked the 3.7-kb TaqI and 2.9-kb KpnI fragments, but had increased hybridization intensity (relative to control DNA samples) in the 3.2-kb TaqI and 4.0-kb KpnI fragments. By contrast, blots with EcoRI or BglII had two large hybridization fragments not different from control DNA samples. These data indicate the presence of two different 21-hydroxylase genes. Additional mapping studies revealed that the two genes had the restriction pattern of the inactive 21-hydroxylase gene. When genomic DNA that had been isolated from all members of this family and from normal subjects was hybridized with the human C4 cDNA probe, the restriction fragment hybridization patterns for all four endonuclease digests were similar in the two groups. Hence, our results suggest that the 21-hydroxylase deficiency of our patients is due to conversion of the active 21-hydroxylase gene to the inactive gene. This gene conversion was associated with absence of functional C4B protein, without any detectable alterations in the restriction fragment pattern of the C4 genes.     

Human cardiac myosin heavy chain genes. Isolation of a genomic DNA clone and its characterization and of a second unique clone also present in the human genome

A gene sequence coding for myosin heavy chain (MHC) of human cardiac muscle was isolated by screening a human genomic library with a 32P-labelled 1.1kb SacI restriction fragment from a previously characterized cDNA clone specifying the light meromyosin and 3' untranslated region of mRNA encoding rabbit cardiac alpha-MHC. The DNA of this human genomic clone (lambda HCMHC8) hybridized much more strongly than did other clones isolated under similar, low stringency conditions both to the rabbit cDNA probe and to mRNA isolated from rat cardiac, but not skeletal, muscle tissue. Probe made from a DNA restriction fragment of lambda HCMHC8 hybridized a single 31S band of human ventricular mRNA. This size is identical to that of cardiac MHC mRNA of other species. Heteroduplex analysis showed hybridization of lambda HCMHC8 with exon segments in a rabbit cardiac MHC genomic clone (lambda MHC alpha 12/1). It also showed that lambda HCMHC8 spanned 14 kb of DNA and contained exon segments estimated to code for two-thirds of a MHC including the carboxylic acid terminus. By rescreening the library under more stringent conditions, where only DNA sequences having strong homology to cardiac MHC genes would be expected to hybridize, clones having restriction maps overlapping lambda HCMHC8 were isolated together with a unique clone (lambda HCMHC9). DNA gel blot hybridization of human genomic DNA with lambda HCMHC8 probe at medium stringency gave a pattern of restriction fragments similar to the restriction map of lambda HCMHC8. A weaker set of bands also appeared which corresponded in pattern to the map of lambda HCMHC9.(ABSTRACT TRUNCATED AT 250 WORDS)