To investigate the existence of the major outer membrane protein (MOMP) gene LipL32 in 15 dominant Chinese strains of 15 serogroups of Leptospira interrogans and 2 international strains of 2 serogroups of Leptospira b...To investigate the existence of the major outer membrane protein (MOMP) gene LipL32 in 15 dominant Chinese strains of 15 serogroups of Leptospira interrogans and 2 international strains of 2 serogroups of Leptospira biflexa, and to clone and construct the expression system as well as to identify the recombinant proteins, genomic DNAs from strains of leptospira were prepared by routine phenol-chloroform method, and the fragments of the LipL32 gene with the whole length from the strains were amplified with high fidelity PCR. The target amplification products were sequenced after T-A cloning, and the expression system for the genes were thereby constructed. Expression of the recombinant proteins was identified by using SDS-PAGE after induction with IPTG at different dosages. Western blot assays with rabbit antiserum against the whole cell of TR/PatocⅠ of Leptospira and immunized serum with rMOMPs were used to determine the immunoreactivity and immunogenicity of the recombinant proteins. Microscopic agglutination test was used to determine the cross- agglutination titres in rabbit sera immunized with rMOMPs, and the cell adherence model of Leptospira was used to examine the blocking effects of rabbit antisera against these rMOMPs. It was found that the LipL32 gene could be found in all the 17 strains of Leptospira mentioned above with two different genotypes, i.e. LipL32/1 and LipL32/2. Amounts of expressions of rMOMP1 and rMOMP2 after IPTG accounted for 40% and 10% of the total bacterial proteins respectively. Both rMOMP1 and rMOMP2 could combine with the rabbit antiserum against leptospiral TR/PatocⅠ, and could induce the production of agglutination antibodies to these 17 strains of Leptospira with 1∶2 to 1∶64 MAT titres. The rabbit anti-rMOMP1 and anti-MOMP2 antibodies at 1∶2 to 1∶16 dilutions could efficiently block adherence of Leptospira. It concludes that all the Leptospira tested in the present study possess LipL32/1 or LipL32/2 genes, and the constructed expression system can express the rMOMP1 and rMOMP2. These recombinant proteins are showed to have good immunogenicity and satisfactory immunoreactivity.展开更多
为探究外膜蛋白A(outer membrane protein A,OmpA)对米尔伊丽莎白菌致病作用的影响,以蛙源米尔伊丽莎白菌FL160902为研究对象,通过同源重组法构建OmpA缺失株△ompA,比较缺失株和野生株的生长特性、生物膜形成能力、抗血清杀伤能力、对...为探究外膜蛋白A(outer membrane protein A,OmpA)对米尔伊丽莎白菌致病作用的影响,以蛙源米尔伊丽莎白菌FL160902为研究对象,通过同源重组法构建OmpA缺失株△ompA,比较缺失株和野生株的生长特性、生物膜形成能力、抗血清杀伤能力、对细胞的黏附能力以及对蛙的致病性差异。结果显示:△ompA的生长能力和抗血清杀伤能力与野生株无显著差异;但与野生株相比,△ompA的生物膜形成能力增加了66%,△ompA对bEnd.3细胞的黏附能力降低了61%;黑斑蛙感染试验显示,△ompA在黑斑蛙血液、脾和脑组织中的载菌量分别为(3.15×10^(8)±0.09×10^(8))、(2.11×10^(8)±0.07×10^(8))和(6.61×10^(8)±0.16×10^(8))copies/g,均显著低于野生株,且△ompA对黑斑蛙的致死率为37%,显著低于野生株的致死率(75%)。上述结果表明,ompA基因缺失不改变米尔伊丽莎白菌的抗血清杀伤能力,但增加了菌株的生物膜形成能力,减弱了菌株的黏附能力,从而降低了该菌对蛙的致病性。展开更多
Helicobacter pylori(H.pylori)is one of the most important human pathogens,infecting approximately half of the global population.Despite its high prevalence,only a subset of H.pylori infected individuals develop seriou...Helicobacter pylori(H.pylori)is one of the most important human pathogens,infecting approximately half of the global population.Despite its high prevalence,only a subset of H.pylori infected individuals develop serious gastroduodenal pathology.The pathogenesis of H.pylori infection and disease outcome is thus thought to be mediated by an intricate interplay between host,environmental and bacterial virulence factors.H.pylori has adapted to the harsh milieu of the human stomach through possession of various virulence genes that enable survival of the bacteria in the acidic environment,movement towards the gastric epithelium,and attachment to gastric epithelial cells.These virulence factors enable successful colonization of the gastric mucosa and sustain persistent H.pylori infection,causing chronic inflammation and tissue damage,which may eventually lead to the development of peptic ulcers and gastric cancer.Numerous studies have focused on the prevalence and role of putative H.pylori virulence genes in disease pathogenesis.While several virulence factors with various functions have been identified,disease associations appear to be less evident,especially among different study populations.This review presents key findings on the most important H.pylori virulence genes,including several bacterial adhesins and toxins,in children and adults,and focuses on their prevalence,clinical significance and potential relationships.展开更多
Objective: To directionally clone the ompl gene fromChlamydia trachomatis (Ct) F genotype onto a plasmid vectorfor constructing a rudimentary DNA vaccine. Methods: The complete ompl gene from genomic DNA of CtF genoty...Objective: To directionally clone the ompl gene fromChlamydia trachomatis (Ct) F genotype onto a plasmid vectorfor constructing a rudimentary DNA vaccine. Methods: The complete ompl gene from genomic DNA of CtF genotype wild species was amplified with primers designedby computer. The recombinant gene was obtained byrestriction enzyme cutting, linking the gene with the plasmidvector in vitro, transforming the recombinant gene intobacteria, and extracting the DNA from the bacteria. Results: DNA extracted from the bacteria was composed ofthe ompl gene and plasmid, which is identified by threemethods of singular restrictive enzyme cutting, doublerestrictive enzyme cutting and PCR. Conclusion: Cloning of the ompl gene from the Ct Fgenotype means that a rudimentary DNA vaccine wassuccessfully constructed.展开更多
A pair of primers were designed according to the published nucleotide sequence of a putative outer membrane protein gene(omp) of Aeromonas hydrophila.With the specific primers,a target fragment about 1.1 kb was amplif...A pair of primers were designed according to the published nucleotide sequence of a putative outer membrane protein gene(omp) of Aeromonas hydrophila.With the specific primers,a target fragment about 1.1 kb was amplified from Aeromonas hydrophila ML316 via PCR.The target fragment was inserted into the linearized pGEM-T easy vector.After enzyme restriction and sequencing analysis,the nucleotide data had been further analyzed by DNAman and ClutalW software.The analysis results showed that the cloned DNA fragment had a longest open reading frame(ORF) of 1035 nt,it predicted to be encoded a 344-aa protein with the molecular weight of 36 kD.Hydrophobicity analysis suggested that the protein was highly hydrophilic,especialy at the first 24 amino-acid,this region could function as signal peptide.The homologious comparison proved the cloned gene had 96% homology to the sequence of the omp gene,and the alignment of the amino acid sequence was 98%.The recombinant plasmid was constructed with the target gene and the expressing vector pGEX-4T-1 and then was transformed into E.coli BL21(DE3)by BamH and Sal I.The fusion protein was expressed under the IPTG inducing condition,and exhibited about 62 kD in size,very close to the predicted molecular weight of GST-MOMP,furthermore,the fusion protein was specifically recognized by anti-serum which raised against the major outer membrane protein of AHML316.Considering all these together,it proved that the cloned gene represented the major outer membrane protein gene of AHML316,and the expressed gene products shared identical antigenicity with the natural main outer membrane protein,and also provided technical support for developing an advanced gene engineering vaccine against Aeromonas hydrophila.展开更多
文摘To investigate the existence of the major outer membrane protein (MOMP) gene LipL32 in 15 dominant Chinese strains of 15 serogroups of Leptospira interrogans and 2 international strains of 2 serogroups of Leptospira biflexa, and to clone and construct the expression system as well as to identify the recombinant proteins, genomic DNAs from strains of leptospira were prepared by routine phenol-chloroform method, and the fragments of the LipL32 gene with the whole length from the strains were amplified with high fidelity PCR. The target amplification products were sequenced after T-A cloning, and the expression system for the genes were thereby constructed. Expression of the recombinant proteins was identified by using SDS-PAGE after induction with IPTG at different dosages. Western blot assays with rabbit antiserum against the whole cell of TR/PatocⅠ of Leptospira and immunized serum with rMOMPs were used to determine the immunoreactivity and immunogenicity of the recombinant proteins. Microscopic agglutination test was used to determine the cross- agglutination titres in rabbit sera immunized with rMOMPs, and the cell adherence model of Leptospira was used to examine the blocking effects of rabbit antisera against these rMOMPs. It was found that the LipL32 gene could be found in all the 17 strains of Leptospira mentioned above with two different genotypes, i.e. LipL32/1 and LipL32/2. Amounts of expressions of rMOMP1 and rMOMP2 after IPTG accounted for 40% and 10% of the total bacterial proteins respectively. Both rMOMP1 and rMOMP2 could combine with the rabbit antiserum against leptospiral TR/PatocⅠ, and could induce the production of agglutination antibodies to these 17 strains of Leptospira with 1∶2 to 1∶64 MAT titres. The rabbit anti-rMOMP1 and anti-MOMP2 antibodies at 1∶2 to 1∶16 dilutions could efficiently block adherence of Leptospira. It concludes that all the Leptospira tested in the present study possess LipL32/1 or LipL32/2 genes, and the constructed expression system can express the rMOMP1 and rMOMP2. These recombinant proteins are showed to have good immunogenicity and satisfactory immunoreactivity.
文摘为探究外膜蛋白A(outer membrane protein A,OmpA)对米尔伊丽莎白菌致病作用的影响,以蛙源米尔伊丽莎白菌FL160902为研究对象,通过同源重组法构建OmpA缺失株△ompA,比较缺失株和野生株的生长特性、生物膜形成能力、抗血清杀伤能力、对细胞的黏附能力以及对蛙的致病性差异。结果显示:△ompA的生长能力和抗血清杀伤能力与野生株无显著差异;但与野生株相比,△ompA的生物膜形成能力增加了66%,△ompA对bEnd.3细胞的黏附能力降低了61%;黑斑蛙感染试验显示,△ompA在黑斑蛙血液、脾和脑组织中的载菌量分别为(3.15×10^(8)±0.09×10^(8))、(2.11×10^(8)±0.07×10^(8))和(6.61×10^(8)±0.16×10^(8))copies/g,均显著低于野生株,且△ompA对黑斑蛙的致死率为37%,显著低于野生株的致死率(75%)。上述结果表明,ompA基因缺失不改变米尔伊丽莎白菌的抗血清杀伤能力,但增加了菌株的生物膜形成能力,减弱了菌株的黏附能力,从而降低了该菌对蛙的致病性。
文摘Helicobacter pylori(H.pylori)is one of the most important human pathogens,infecting approximately half of the global population.Despite its high prevalence,only a subset of H.pylori infected individuals develop serious gastroduodenal pathology.The pathogenesis of H.pylori infection and disease outcome is thus thought to be mediated by an intricate interplay between host,environmental and bacterial virulence factors.H.pylori has adapted to the harsh milieu of the human stomach through possession of various virulence genes that enable survival of the bacteria in the acidic environment,movement towards the gastric epithelium,and attachment to gastric epithelial cells.These virulence factors enable successful colonization of the gastric mucosa and sustain persistent H.pylori infection,causing chronic inflammation and tissue damage,which may eventually lead to the development of peptic ulcers and gastric cancer.Numerous studies have focused on the prevalence and role of putative H.pylori virulence genes in disease pathogenesis.While several virulence factors with various functions have been identified,disease associations appear to be less evident,especially among different study populations.This review presents key findings on the most important H.pylori virulence genes,including several bacterial adhesins and toxins,in children and adults,and focuses on their prevalence,clinical significance and potential relationships.
文摘Objective: To directionally clone the ompl gene fromChlamydia trachomatis (Ct) F genotype onto a plasmid vectorfor constructing a rudimentary DNA vaccine. Methods: The complete ompl gene from genomic DNA of CtF genotype wild species was amplified with primers designedby computer. The recombinant gene was obtained byrestriction enzyme cutting, linking the gene with the plasmidvector in vitro, transforming the recombinant gene intobacteria, and extracting the DNA from the bacteria. Results: DNA extracted from the bacteria was composed ofthe ompl gene and plasmid, which is identified by threemethods of singular restrictive enzyme cutting, doublerestrictive enzyme cutting and PCR. Conclusion: Cloning of the ompl gene from the Ct Fgenotype means that a rudimentary DNA vaccine wassuccessfully constructed.
文摘A pair of primers were designed according to the published nucleotide sequence of a putative outer membrane protein gene(omp) of Aeromonas hydrophila.With the specific primers,a target fragment about 1.1 kb was amplified from Aeromonas hydrophila ML316 via PCR.The target fragment was inserted into the linearized pGEM-T easy vector.After enzyme restriction and sequencing analysis,the nucleotide data had been further analyzed by DNAman and ClutalW software.The analysis results showed that the cloned DNA fragment had a longest open reading frame(ORF) of 1035 nt,it predicted to be encoded a 344-aa protein with the molecular weight of 36 kD.Hydrophobicity analysis suggested that the protein was highly hydrophilic,especialy at the first 24 amino-acid,this region could function as signal peptide.The homologious comparison proved the cloned gene had 96% homology to the sequence of the omp gene,and the alignment of the amino acid sequence was 98%.The recombinant plasmid was constructed with the target gene and the expressing vector pGEX-4T-1 and then was transformed into E.coli BL21(DE3)by BamH and Sal I.The fusion protein was expressed under the IPTG inducing condition,and exhibited about 62 kD in size,very close to the predicted molecular weight of GST-MOMP,furthermore,the fusion protein was specifically recognized by anti-serum which raised against the major outer membrane protein of AHML316.Considering all these together,it proved that the cloned gene represented the major outer membrane protein gene of AHML316,and the expressed gene products shared identical antigenicity with the natural main outer membrane protein,and also provided technical support for developing an advanced gene engineering vaccine against Aeromonas hydrophila.
