Duck circovirus (DuCV),a potential immunosuppressive virus,was investigated in Southern China from March 2006 to December 2009 by using a polymerase chain reaction (PCR) based method.In this study,a total of 138 sick ...Duck circovirus (DuCV),a potential immunosuppressive virus,was investigated in Southern China from March 2006 to December 2009 by using a polymerase chain reaction (PCR) based method.In this study,a total of 138 sick or dead duck samples from 18 different farms were examined with an average DuCV infection rate of ～35%.It was found that ducks between the ages of 40～60 days were more susceptible to DuCV.There was no evidence showing that the DuCV virus was capable of vertical transmission.Farms with positive PCR results exhibited no regularly apparent clinical abnormalities such as feathering disorders,growth retardation or lower-than-average weight.The complete genomes of 9 strains from Fujian Province and 1 from Zhejiang Province were sequenced and analyzed.The 10 DuCV genomes,compared with others genomes downloaded from GenBank,ranged in size from 1988 to 1996 base pairs,with sequence identities ranging from 83.2% to 99.8%.Phylogenetic analysis based on genome sequences demonstrated that DuCVs can be divided into two distinct genetic genotypes,GroupⅠ(the Euro-USA lineage) and GroupⅡ(the Taiwan lineage),with approximately 10.0% genetic difference between the two types.Molecular epidemiological data suggest there is no obvious difference among DuCV strains isolated from different geographic locations or different species,including Duck,Muscovy duck,Mule duck,Cheery duck,Mulard duck and Pekin duck.展开更多
To investigate molecular epidemiology of DuCV in Cherry Valley ducks in China, the complete genomes of six DuCV strains, which were detected from Cherry Valley ducks in China between 2007 and 2008, were sequenced. Seq...To investigate molecular epidemiology of DuCV in Cherry Valley ducks in China, the complete genomes of six DuCV strains, which were detected from Cherry Valley ducks in China between 2007 and 2008, were sequenced. Sequence and phylogenetic analysis were carried out to compare these six strains with another 27 DuCV strains from Mulard duck, Muscovy duck, Pekin ducks and Mule duck. The analysis showed that the six DuCV strains exhibited typical genetic features of the family of DuCV, such as a stem-loop structure, three major open reading frames (Rep, Cap and ORF3), four intergenic repeats and the conserved motifs for rolling circle replication and for the dNTP binding domain located in the Rep protein. Phylogenetic analysis of the nucleotide sequences of the complete genome and Cap gene of these strains together with those that have been previously published demonstrated two distinct DuCV genotypes. The DuCV strains with complete genomes containing 1988 and 1989 nucleotides clustered in genotype A, whereas the strains with complete genomes containing 1991, 1992, 1995 and 1996 nucleotides lay in genotype B. The six DuCV strains from Cherry Valley ducks were divided into the two groups. The results of the study provides some insight into the variation of DuCVs in Cherry Valley ducks.展开更多
The capsid （Cap） protein, which is the only structural protein of duck circovirus （DuCV）, is the most important antigen for the development of vaccines against DuCV and the virus＇s serological diagnostic methods....The capsid （Cap） protein, which is the only structural protein of duck circovirus （DuCV）, is the most important antigen for the development of vaccines against DuCV and the virus＇s serological diagnostic methods. In order to use yeast expression system to produce a large quantities of DuCVCap protein which is close to its natural form to display the antigen peptides perfectly, the Cap gene was optimized into the codon-optimized capsid （Opt-Cap） gene towards the preference of yeast firstly. Then, the genes of Cap and Opt-Cap were separately cloned into pPIC9K plasmid and transformed into Picha pas- toris GSl15. The strains that displayed the phenotype of Mut~ and contained multiple inserts of expression cassette were selected from those colonies. After the induction expression, the secretory type of Cap protein, which was about 43 kDa, was best expressed under 0.5% （v/v） methanol and sorbitol induction. Compared with the Cap gene, the expression level of Opt-Cap gene was much higher. What＇s more, the purified Cap protein had a good reactivity to its specific polyclone antibody and DuCV-positive serum, and it was able to self-assemble into virus-like particles （VLPs）. These VLPs, with a diameter of 15-20 nm and without a nucleic acid structure, showed a high level of similarity to DuCV particles in size and shape. All of the resultsdemonstrated that, based on the codon-optimization, it is suitable to use the P. pastoris expression system to produce DuCV VLPs on a large scale. It is the first time that a large amounts of DuCV VLPs were produced successfully in P. pastoris, which might be particularly useful for the further studies of serological diagnosis and vaccines of DuCV.展开更多
Duck circovirus infection is an immunosuppressive disease that is characterized by growth retardant and odd deaths. Its infection is usually combined with other pathogens, making the clinical diagnosis more difficult....Duck circovirus infection is an immunosuppressive disease that is characterized by growth retardant and odd deaths. Its infection is usually combined with other pathogens, making the clinical diagnosis more difficult. With the rapid development of molecular biological and immunological technologies, the laboratory diagnostic methods for duck circovirus infection also advance greatly. The paper summarizes the research advances in various laboratory detection methods for duck cireovirus infection including PCR, nested PCR, multiple PCR, fluorescence quantitative PCR, LAMP, nucleic acid probe and ELISA, as well as their ad- vantages and shortages, aiming at providing reference for finding novel detection methods and for the diagnosis and comprehensive prevention and control.展开更多
The objective of this study was to construct the recombinant eukaryotic expression plasmid of ORF2 gene harboring enhanced green fluorescent protein （EGFP） report gene. ORF2 gene of porcine circovirus type 2 cloned ...The objective of this study was to construct the recombinant eukaryotic expression plasmid of ORF2 gene harboring enhanced green fluorescent protein （EGFP） report gene. ORF2 gene of porcine circovirus type 2 cloned by PCR was ligated to the expression vector pEGFP-N1, which contains enhanced green fluorescent protein （EGFP） report gene, the recombinant eukaryotic expression plasmid pEGFP-N1-ORF2 was constructed successfully and was transfected into pre- pared duck myocardial cells （DMCs） by lipofectin. According to the result, the fluorescence expression was directly detected with fluorescence microscope, and the expression of ORF2 were analyzed by RT-PCR and indirect immunofluorescence assay （IFA） respectively. About 48 h after transfection, green fluorescent can be observed on transfected cells ： T-PCR and IFA were positive. This indicated that ORF2 gene of PCV2 was expressed efficiently in transfected duck myocardial cells.展开更多
基金Modern Agri-industry Technology Research System(CARS-43)Science and Technology Innovation Fund of Fujian Academy of Agriculture Science(STIF-02)Science and Technology Innovation Foundation for Young Scientists of Fujian Academy of Agriculture Science(2008QB-6)
文摘Duck circovirus (DuCV),a potential immunosuppressive virus,was investigated in Southern China from March 2006 to December 2009 by using a polymerase chain reaction (PCR) based method.In this study,a total of 138 sick or dead duck samples from 18 different farms were examined with an average DuCV infection rate of ～35%.It was found that ducks between the ages of 40～60 days were more susceptible to DuCV.There was no evidence showing that the DuCV virus was capable of vertical transmission.Farms with positive PCR results exhibited no regularly apparent clinical abnormalities such as feathering disorders,growth retardation or lower-than-average weight.The complete genomes of 9 strains from Fujian Province and 1 from Zhejiang Province were sequenced and analyzed.The 10 DuCV genomes,compared with others genomes downloaded from GenBank,ranged in size from 1988 to 1996 base pairs,with sequence identities ranging from 83.2% to 99.8%.Phylogenetic analysis based on genome sequences demonstrated that DuCVs can be divided into two distinct genetic genotypes,GroupⅠ(the Euro-USA lineage) and GroupⅡ(the Taiwan lineage),with approximately 10.0% genetic difference between the two types.Molecular epidemiological data suggest there is no obvious difference among DuCV strains isolated from different geographic locations or different species,including Duck,Muscovy duck,Mule duck,Cheery duck,Mulard duck and Pekin duck.
基金the grant of Shandong Province Higher Educational Science and Technology Program (J08LF07)Shandong Provincial Natural Sciences Fund (Q2006D04)
文摘To investigate molecular epidemiology of DuCV in Cherry Valley ducks in China, the complete genomes of six DuCV strains, which were detected from Cherry Valley ducks in China between 2007 and 2008, were sequenced. Sequence and phylogenetic analysis were carried out to compare these six strains with another 27 DuCV strains from Mulard duck, Muscovy duck, Pekin ducks and Mule duck. The analysis showed that the six DuCV strains exhibited typical genetic features of the family of DuCV, such as a stem-loop structure, three major open reading frames (Rep, Cap and ORF3), four intergenic repeats and the conserved motifs for rolling circle replication and for the dNTP binding domain located in the Rep protein. Phylogenetic analysis of the nucleotide sequences of the complete genome and Cap gene of these strains together with those that have been previously published demonstrated two distinct DuCV genotypes. The DuCV strains with complete genomes containing 1988 and 1989 nucleotides clustered in genotype A, whereas the strains with complete genomes containing 1991, 1992, 1995 and 1996 nucleotides lay in genotype B. The six DuCV strains from Cherry Valley ducks were divided into the two groups. The results of the study provides some insight into the variation of DuCVs in Cherry Valley ducks.
基金supported by the National Science and Technology Support Program(2015BAD12B05)the China Agricultural Research System(CARS-43-8)+2 种基金the Integration and Demonstration of Key Technologies for Duck Industrial in Sichuan Province,China(2014NZ0030)the Ministry of Education Program of China(20125103110013)the Sichuan Province Research Programs,China(2013HH0042/2013 TD0015/2014-002)
文摘The capsid （Cap） protein, which is the only structural protein of duck circovirus （DuCV）, is the most important antigen for the development of vaccines against DuCV and the virus＇s serological diagnostic methods. In order to use yeast expression system to produce a large quantities of DuCVCap protein which is close to its natural form to display the antigen peptides perfectly, the Cap gene was optimized into the codon-optimized capsid （Opt-Cap） gene towards the preference of yeast firstly. Then, the genes of Cap and Opt-Cap were separately cloned into pPIC9K plasmid and transformed into Picha pas- toris GSl15. The strains that displayed the phenotype of Mut~ and contained multiple inserts of expression cassette were selected from those colonies. After the induction expression, the secretory type of Cap protein, which was about 43 kDa, was best expressed under 0.5% （v/v） methanol and sorbitol induction. Compared with the Cap gene, the expression level of Opt-Cap gene was much higher. What＇s more, the purified Cap protein had a good reactivity to its specific polyclone antibody and DuCV-positive serum, and it was able to self-assemble into virus-like particles （VLPs）. These VLPs, with a diameter of 15-20 nm and without a nucleic acid structure, showed a high level of similarity to DuCV particles in size and shape. All of the resultsdemonstrated that, based on the codon-optimization, it is suitable to use the P. pastoris expression system to produce DuCV VLPs on a large scale. It is the first time that a large amounts of DuCV VLPs were produced successfully in P. pastoris, which might be particularly useful for the further studies of serological diagnosis and vaccines of DuCV.
文摘Duck circovirus infection is an immunosuppressive disease that is characterized by growth retardant and odd deaths. Its infection is usually combined with other pathogens, making the clinical diagnosis more difficult. With the rapid development of molecular biological and immunological technologies, the laboratory diagnostic methods for duck circovirus infection also advance greatly. The paper summarizes the research advances in various laboratory detection methods for duck cireovirus infection including PCR, nested PCR, multiple PCR, fluorescence quantitative PCR, LAMP, nucleic acid probe and ELISA, as well as their ad- vantages and shortages, aiming at providing reference for finding novel detection methods and for the diagnosis and comprehensive prevention and control.
基金Supported by Young and Middle-Aged Scientists Research Awards Fund of Shangdong Province(BS2011SW026)
文摘The objective of this study was to construct the recombinant eukaryotic expression plasmid of ORF2 gene harboring enhanced green fluorescent protein （EGFP） report gene. ORF2 gene of porcine circovirus type 2 cloned by PCR was ligated to the expression vector pEGFP-N1, which contains enhanced green fluorescent protein （EGFP） report gene, the recombinant eukaryotic expression plasmid pEGFP-N1-ORF2 was constructed successfully and was transfected into pre- pared duck myocardial cells （DMCs） by lipofectin. According to the result, the fluorescence expression was directly detected with fluorescence microscope, and the expression of ORF2 were analyzed by RT-PCR and indirect immunofluorescence assay （IFA） respectively. About 48 h after transfection, green fluorescent can be observed on transfected cells ： T-PCR and IFA were positive. This indicated that ORF2 gene of PCV2 was expressed efficiently in transfected duck myocardial cells.
