Very virulent infectious bursal disease virus(vvIBDV)was isolated from chicken bursa and then the virus double stranded RNA was extracted After denaturation of dsRNA by heat in the presence of primers,the cDNA was syn...Very virulent infectious bursal disease virus(vvIBDV)was isolated from chicken bursa and then the virus double stranded RNA was extracted After denaturation of dsRNA by heat in the presence of primers,the cDNA was synthesized by use of a reverse transcriptase lacking RNase H activity The RNA component of RNA cDNA hybrids was digested by RNase H By using an optimized PCR,a 3 05kb DNA fragment coding for precursor polyprotein of IBDV was produced in one step,which was inserted into pcDNA3 1(+) vector Two recombinant plasmids (pPP1 and pPP2)were screened and identified from eight XL1 blue colonies Partial sequencing for pPP1 plasmid indicated that the precursor polyprotein gene for IBDV was cloned successfully The method can simplify greatly the procedure to clone precursor polyprotein gene of IBDV展开更多
The World Health Organization has declared the present Zika virus epidemic to be a ＇Public Health Emergency of International Concern＇. The virus appears to have spread from Thailand to French Polynesia in 2013, and ...The World Health Organization has declared the present Zika virus epidemic to be a ＇Public Health Emergency of International Concern＇. The virus appears to have spread from Thailand to French Polynesia in 2013, and has since infected over a million people in the countries of South and Central America. In most cases the infection is mild and transient, but the virus does appear to be strongly neurotropic and the presumptive cause of both birth defects in fetuses and Guillain-Barr6 syndrome in some adults. In this paper, the techniques and utilities developed in the study of mitochondrial DNA were applied to the Zika virus. As a result, it is possible to show in a simple manner how a phylogenetic tree may be constructed and how the mutation rate of the virus can be measured. The study showed the mutation rate to vary between 12 and 25 bases a year, in a viral genome of 10 272 bases. This rapid mutation rate will enable the geographic spread of the epidemic to be monitored easily and may also prove useful in assisting the identification of preventative measures that are working, and those that are not.展开更多
A total of 288 grapevine samples of 61 different grapevine cultivars,collected from 22 provinces and regions,were analyzed by reverse transcription-PCR(RT-PCR) for the presence of grapevine fabavirus(GFabV).PCR detect...A total of 288 grapevine samples of 61 different grapevine cultivars,collected from 22 provinces and regions,were analyzed by reverse transcription-PCR(RT-PCR) for the presence of grapevine fabavirus(GFabV).PCR detection results showed the incidences of GFabV were 12.8%(30/235) and 48.1%(25/52) in the asymptomatic and symptomatic vines,respectively.The genetic diversity of GFabV isolates was analyzed based on partial nucleotide and encoded amino acid sequences of the RNA1 and RNA2 polyprotein genes.Phylogenetic analyses of the RNA1 and RNA2 gene sequences divided the GFabV isolates into five well-defined groups.Groups 1,2,and 4 comprised only Chinese isolates.This article represents the first report for the prevalence and genetic diversity of GFabV in grapevines grown in China.展开更多
文摘Very virulent infectious bursal disease virus(vvIBDV)was isolated from chicken bursa and then the virus double stranded RNA was extracted After denaturation of dsRNA by heat in the presence of primers,the cDNA was synthesized by use of a reverse transcriptase lacking RNase H activity The RNA component of RNA cDNA hybrids was digested by RNase H By using an optimized PCR,a 3 05kb DNA fragment coding for precursor polyprotein of IBDV was produced in one step,which was inserted into pcDNA3 1(+) vector Two recombinant plasmids (pPP1 and pPP2)were screened and identified from eight XL1 blue colonies Partial sequencing for pPP1 plasmid indicated that the precursor polyprotein gene for IBDV was cloned successfully The method can simplify greatly the procedure to clone precursor polyprotein gene of IBDV
文摘The World Health Organization has declared the present Zika virus epidemic to be a ＇Public Health Emergency of International Concern＇. The virus appears to have spread from Thailand to French Polynesia in 2013, and has since infected over a million people in the countries of South and Central America. In most cases the infection is mild and transient, but the virus does appear to be strongly neurotropic and the presumptive cause of both birth defects in fetuses and Guillain-Barr6 syndrome in some adults. In this paper, the techniques and utilities developed in the study of mitochondrial DNA were applied to the Zika virus. As a result, it is possible to show in a simple manner how a phylogenetic tree may be constructed and how the mutation rate of the virus can be measured. The study showed the mutation rate to vary between 12 and 25 bases a year, in a viral genome of 10 272 bases. This rapid mutation rate will enable the geographic spread of the epidemic to be monitored easily and may also prove useful in assisting the identification of preventative measures that are working, and those that are not.
基金supported by the National Key R&D Program of China(2018YFD0201301)the earmarked fund for the China Agriculture Research System(CARS-29-bc-1)the Fundamental Research Funds for Central Non-profit Scientific Institutions,China
文摘A total of 288 grapevine samples of 61 different grapevine cultivars,collected from 22 provinces and regions,were analyzed by reverse transcription-PCR(RT-PCR) for the presence of grapevine fabavirus(GFabV).PCR detection results showed the incidences of GFabV were 12.8%(30/235) and 48.1%(25/52) in the asymptomatic and symptomatic vines,respectively.The genetic diversity of GFabV isolates was analyzed based on partial nucleotide and encoded amino acid sequences of the RNA1 and RNA2 polyprotein genes.Phylogenetic analyses of the RNA1 and RNA2 gene sequences divided the GFabV isolates into five well-defined groups.Groups 1,2,and 4 comprised only Chinese isolates.This article represents the first report for the prevalence and genetic diversity of GFabV in grapevines grown in China.
