Newcastle disease( ND) is one of the most serious infectious diseases that infect the poultry industry.There is only one serotype of Newcastle disease virus( NDV),but NDVs can be divided into two distinct classes( cla...Newcastle disease( ND) is one of the most serious infectious diseases that infect the poultry industry.There is only one serotype of Newcastle disease virus( NDV),but NDVs can be divided into two distinct classes( class Ⅰ,and class Ⅱ) according to their genetic relationship.To develop a method for rapid quantitative detection of class Ⅰ NDV,a pair of primers and a TaqM an probe were designed and synthesized according to the conservative sequence of NP gene of class Ⅰ NDV.The positive recombinant plasmid harboring NP gene of JS-18-05 isolate was used as a positive template to establish the standard curve.A real-time fluorescent quantitative RT-PCR method was established for rapid detection of class Ⅰ NDV with strong specificity,high sensitivity and good repeatability.The established method exhibited a good linear relationship within the concentration of 102 to 108 copies of NDV,by which 1 μl of 10 copy of NDV nucleic acid could be detected in the initial template.Compared with conventional virus isolation methods,the established method had similar sensitivity and led to the same results in detecting33 class Ⅰ,class Ⅱ NDV isolates.The study provided the basis for rapid quantitative detection of class Ⅰ NDVs and further clarification of their pathogenicity and pathogenic mechanism in poultry.展开更多
[Objective] The aim of this paper was to study the genotype, pathogenicity and nucleotide difference between Newcastle disease virus(NDV) isolates and traditional NDV vaccine strain(La Sota). [Method] A suspected NDV ...[Objective] The aim of this paper was to study the genotype, pathogenicity and nucleotide difference between Newcastle disease virus(NDV) isolates and traditional NDV vaccine strain(La Sota). [Method] A suspected NDV strain was isolated from a chicken farm. The isolate was preliminarily determined by HA and HI tests. A pair of primers was designed based on the partial sequence of NDV F gene published in GenBank(accession No. JF950510.1). F gene was amplified by RT-PCR, cloned and sequenced. The sequencing result was compared with the F gene sequences published in GenBank, and the phylogenetic tree was constructed to analyze the genotypes. The pathogenicity of the virus was determined by mean death time(MDT) of chicken embryos, intracerebral pathogenicity index(ICPI) of one-day-old chicks and intravenous pathogenicity index(IVPI) of six-week-old chickens, respectively. Based on the NDV genome sequence published in GenBank(accession No. JF950510.1), nine pairs of primers were designed to amplify the genome sequence of the isolate, and its structure was analyzed. [Result] The length of F gene was about 500 bp, and a NDV strain of genotype VII was isolated. The MDT, ICPI and IVPI were 52.8 h, 1.675 and 2.46, respectively, indicating the isolate was a virulent strain. The whole genome sequence analysis results showed that the full genome length of the isolate was 15 192 bp, which had 6 more nu-cleotides than that of La Sota strain, and the homology between the two strains was 82.8%. [Conclusion] A virulent NDV strain of genotype Ⅶ was isolated, with low homology to La Sota strain in nucleotide sequence.展开更多
The influence of antibody immune selective pressure on Newcastle disease virus (NDV) HN and F gene mutations was studied in cell cultures.NDV field strain TZ060107 was inoculated into chicken embryo fibroblast cells a...The influence of antibody immune selective pressure on Newcastle disease virus (NDV) HN and F gene mutations was studied in cell cultures.NDV field strain TZ060107 was inoculated into chicken embryo fibroblast cells and continuously passaged with (group A) or without (group B) anti-NDV monospecific serum.Each group contained three independent passage series.HN and F genes were amplified and sequenced for the 10th,20th,30th,40th and 50th generations of each serial passage,and compared with the original strain.The results demonstrated that increased HN gene mutations were observed in group A with the antibody than in group B without the antibody.The nonsynonymous (NS) to synonymous (S) mutations ratio was 6 for group A,significantly higher than 3.4 in group B.In group A with the antibody,there were five stable NS mutations in HN gene,three of which (related to aa#353,521 and 568) were related to known epitopes.There were two stable NS mutations in F gene in group A,but no stable NS mutations in group B.The NS/S ratios of F gene were less than 2.5 for both groups A and B.Our results suggested that the antibody strongly influenced HN gene mutations,while the F gene was less influenced by the same antibody.展开更多
基金Supported by National Natural Science Foundation of China(30630048)National Science and Technology Support Program(2006BAD06A03)
文摘Newcastle disease( ND) is one of the most serious infectious diseases that infect the poultry industry.There is only one serotype of Newcastle disease virus( NDV),but NDVs can be divided into two distinct classes( class Ⅰ,and class Ⅱ) according to their genetic relationship.To develop a method for rapid quantitative detection of class Ⅰ NDV,a pair of primers and a TaqM an probe were designed and synthesized according to the conservative sequence of NP gene of class Ⅰ NDV.The positive recombinant plasmid harboring NP gene of JS-18-05 isolate was used as a positive template to establish the standard curve.A real-time fluorescent quantitative RT-PCR method was established for rapid detection of class Ⅰ NDV with strong specificity,high sensitivity and good repeatability.The established method exhibited a good linear relationship within the concentration of 102 to 108 copies of NDV,by which 1 μl of 10 copy of NDV nucleic acid could be detected in the initial template.Compared with conventional virus isolation methods,the established method had similar sensitivity and led to the same results in detecting33 class Ⅰ,class Ⅱ NDV isolates.The study provided the basis for rapid quantitative detection of class Ⅰ NDVs and further clarification of their pathogenicity and pathogenic mechanism in poultry.
基金Supported by Science and Technology Innovation Leading Talent of Qingdao City(16-8-3-14-zhc)
文摘[Objective] The aim of this paper was to study the genotype, pathogenicity and nucleotide difference between Newcastle disease virus(NDV) isolates and traditional NDV vaccine strain(La Sota). [Method] A suspected NDV strain was isolated from a chicken farm. The isolate was preliminarily determined by HA and HI tests. A pair of primers was designed based on the partial sequence of NDV F gene published in GenBank(accession No. JF950510.1). F gene was amplified by RT-PCR, cloned and sequenced. The sequencing result was compared with the F gene sequences published in GenBank, and the phylogenetic tree was constructed to analyze the genotypes. The pathogenicity of the virus was determined by mean death time(MDT) of chicken embryos, intracerebral pathogenicity index(ICPI) of one-day-old chicks and intravenous pathogenicity index(IVPI) of six-week-old chickens, respectively. Based on the NDV genome sequence published in GenBank(accession No. JF950510.1), nine pairs of primers were designed to amplify the genome sequence of the isolate, and its structure was analyzed. [Result] The length of F gene was about 500 bp, and a NDV strain of genotype VII was isolated. The MDT, ICPI and IVPI were 52.8 h, 1.675 and 2.46, respectively, indicating the isolate was a virulent strain. The whole genome sequence analysis results showed that the full genome length of the isolate was 15 192 bp, which had 6 more nu-cleotides than that of La Sota strain, and the homology between the two strains was 82.8%. [Conclusion] A virulent NDV strain of genotype Ⅶ was isolated, with low homology to La Sota strain in nucleotide sequence.
基金supported by the Shandong Province Application Technology Innovation Project on Agriculture during 2007 and 2008
文摘The influence of antibody immune selective pressure on Newcastle disease virus (NDV) HN and F gene mutations was studied in cell cultures.NDV field strain TZ060107 was inoculated into chicken embryo fibroblast cells and continuously passaged with (group A) or without (group B) anti-NDV monospecific serum.Each group contained three independent passage series.HN and F genes were amplified and sequenced for the 10th,20th,30th,40th and 50th generations of each serial passage,and compared with the original strain.The results demonstrated that increased HN gene mutations were observed in group A with the antibody than in group B without the antibody.The nonsynonymous (NS) to synonymous (S) mutations ratio was 6 for group A,significantly higher than 3.4 in group B.In group A with the antibody,there were five stable NS mutations in HN gene,three of which (related to aa#353,521 and 568) were related to known epitopes.There were two stable NS mutations in F gene in group A,but no stable NS mutations in group B.The NS/S ratios of F gene were less than 2.5 for both groups A and B.Our results suggested that the antibody strongly influenced HN gene mutations,while the F gene was less influenced by the same antibody.
