Porcine circoviruses(PCV) include PCV1, PCV2, and the new-emerging PCV3. PCV2 is pathogenic to pigs, but the pathogenicity of PCV3 in pigs is debatable. Recently, there have been frequent reports of PCV2 and PCV3 co-i...Porcine circoviruses(PCV) include PCV1, PCV2, and the new-emerging PCV3. PCV2 is pathogenic to pigs, but the pathogenicity of PCV3 in pigs is debatable. Recently, there have been frequent reports of PCV2 and PCV3 co-infections in clinical samples. Thus, it would be practical to develop a duplex PCR method to detect PCV2 and PCV3 simultaneously. In this study, specific primers and probes were designed to target PCV2 cap and PCV3 rep genes. A duplex real-time PCR method was then developed to detect the two viruses. The assay was found to be highly specific, sensitive, and reproducible for PCV2/3 without cross-reactions with other swine pathogens. The sensitivity of this assay was 2.9 copies for the PCV2 plasmid and 22.5 copies for the PCV3 plasmid. The established assay was then used to detect PCV2/3 infection in 340 clinical samples collected in the first half of 2017. The results showed that the co-infection rate of PCV2/3 in the samples was 27.6%. Our study provides an important tool that can be used to perform urgently needed surveys for the two porcine circoviruses to evaluate their impact on the swine industry.展开更多
The establishment of highly sensitive diagnostic methods is critical in the early diagnosis and control of Zika virus(ZIKV)and in preventing serious neurological complications of ZIKV infection. In this study, we esta...The establishment of highly sensitive diagnostic methods is critical in the early diagnosis and control of Zika virus(ZIKV)and in preventing serious neurological complications of ZIKV infection. In this study, we established micro-droplet digital polymerase chain reaction(ddPCR) and real-time quantitative PCR(RT-qPCR) protocols for the detection of ZIKV based on the amplification of the NS5 gene. For the ZIKV standard plasmid, the RT-qPCR results showed that the cycle threshold(Ct) value was linear from 10~1 to 10~8 copy/l L, with a standard curve R^2 of 0.999 and amplification efficiency of 92.203%;however, a concentration as low as 1 copy/l L could not be detected. In comparison with RT-qPCR, the dd PCR method resulted in a linear range of 10~1–10~4 copy/l L and was able to detect concentrations as low as 1 copy/l L. Thus, for detecting ZIKV from clinical samples, RT-qPCR is a better choice for high-concentration samples(above 10~1 copy/l L),while ddPCR has excellent accuracy and sensitivity for low-concentration samples. These results indicate that the ddPCR method should be of considerable use in the early diagnosis, laboratory study, and monitoring of ZIKV.展开更多
Wheat dwarf disease caused by wheat dwarf virus(WDV) is currently present in wheat growing regions in China and causes serious losses in wheat yield. To develop reliable and effective serological detection methods for...Wheat dwarf disease caused by wheat dwarf virus(WDV) is currently present in wheat growing regions in China and causes serious losses in wheat yield. To develop reliable and effective serological detection methods for WDV, the coat protein(CP) gene of WDV was cloned and expressed in Escherichia coli. The purified recombinant CP protein was immunized to BALB/c mice, and four hybridoma cell lines(i.e. 18G10, 9G4, 23F4 and 22A10) secreting anti-WDV monoclonal antibodies(MAbs) were obtained through the hybridoma technique. Using the prepared MAbs, an antigencoated-plate enzyme-linked immunosorbent assay(ACP-ELISA) and a dot-ELISA were established for detecting WDV in wheat samples. The most sensitive ACP-ELISA based on MAb 23F4 or 22A10 was able to detect WDV in 1:163,840(w/v,g/mL) diluted WDV-infected wheat plant crude extracts. The dot-ELISA based on MAb 23F4 was the most sensitive and able to detect the virus in 1:5,120(w/v, g/mL) diluted wheat plant crude extracts. A total of 128 wheat samples were collected from wheat growing regions in the Shaanxi and Qinghai provinces, China, and were screened for the presence of WDV using two developed serological assays. Results from the survey showed that approximately 62% of the samples were infected with WDV. PCR followed by DNA sequencing and sequence alignment validated the results from the two serological assays. Therefore, we consider that these two serological detection methods can be significantly useful for the control of WDV in China.展开更多
基金supported by Grants from the National Key Research and Development Program (2016YFD0500703)Major Science and Technology Projects in Henan Province (171100110200)Luoyang HeLuo Talent Plan (Dr. Kegong Tian)
文摘Porcine circoviruses(PCV) include PCV1, PCV2, and the new-emerging PCV3. PCV2 is pathogenic to pigs, but the pathogenicity of PCV3 in pigs is debatable. Recently, there have been frequent reports of PCV2 and PCV3 co-infections in clinical samples. Thus, it would be practical to develop a duplex PCR method to detect PCV2 and PCV3 simultaneously. In this study, specific primers and probes were designed to target PCV2 cap and PCV3 rep genes. A duplex real-time PCR method was then developed to detect the two viruses. The assay was found to be highly specific, sensitive, and reproducible for PCV2/3 without cross-reactions with other swine pathogens. The sensitivity of this assay was 2.9 copies for the PCV2 plasmid and 22.5 copies for the PCV3 plasmid. The established assay was then used to detect PCV2/3 infection in 340 clinical samples collected in the first half of 2017. The results showed that the co-infection rate of PCV2/3 in the samples was 27.6%. Our study provides an important tool that can be used to perform urgently needed surveys for the two porcine circoviruses to evaluate their impact on the swine industry.
基金supported by the National Natural Science Foundation of China (Nos. 31470271 and 81730110)Guangzhou Science and Technology Program key projects (No. 201803040006)
文摘The establishment of highly sensitive diagnostic methods is critical in the early diagnosis and control of Zika virus(ZIKV)and in preventing serious neurological complications of ZIKV infection. In this study, we established micro-droplet digital polymerase chain reaction(ddPCR) and real-time quantitative PCR(RT-qPCR) protocols for the detection of ZIKV based on the amplification of the NS5 gene. For the ZIKV standard plasmid, the RT-qPCR results showed that the cycle threshold(Ct) value was linear from 10~1 to 10~8 copy/l L, with a standard curve R^2 of 0.999 and amplification efficiency of 92.203%;however, a concentration as low as 1 copy/l L could not be detected. In comparison with RT-qPCR, the dd PCR method resulted in a linear range of 10~1–10~4 copy/l L and was able to detect concentrations as low as 1 copy/l L. Thus, for detecting ZIKV from clinical samples, RT-qPCR is a better choice for high-concentration samples(above 10~1 copy/l L),while ddPCR has excellent accuracy and sensitivity for low-concentration samples. These results indicate that the ddPCR method should be of considerable use in the early diagnosis, laboratory study, and monitoring of ZIKV.
基金supported by Public Science and Technology Research Funds Projects of Agriculture (201303021)the National Basic Research Program (973) of China (No.2014CB138400)
文摘Wheat dwarf disease caused by wheat dwarf virus(WDV) is currently present in wheat growing regions in China and causes serious losses in wheat yield. To develop reliable and effective serological detection methods for WDV, the coat protein(CP) gene of WDV was cloned and expressed in Escherichia coli. The purified recombinant CP protein was immunized to BALB/c mice, and four hybridoma cell lines(i.e. 18G10, 9G4, 23F4 and 22A10) secreting anti-WDV monoclonal antibodies(MAbs) were obtained through the hybridoma technique. Using the prepared MAbs, an antigencoated-plate enzyme-linked immunosorbent assay(ACP-ELISA) and a dot-ELISA were established for detecting WDV in wheat samples. The most sensitive ACP-ELISA based on MAb 23F4 or 22A10 was able to detect WDV in 1:163,840(w/v,g/mL) diluted WDV-infected wheat plant crude extracts. The dot-ELISA based on MAb 23F4 was the most sensitive and able to detect the virus in 1:5,120(w/v, g/mL) diluted wheat plant crude extracts. A total of 128 wheat samples were collected from wheat growing regions in the Shaanxi and Qinghai provinces, China, and were screened for the presence of WDV using two developed serological assays. Results from the survey showed that approximately 62% of the samples were infected with WDV. PCR followed by DNA sequencing and sequence alignment validated the results from the two serological assays. Therefore, we consider that these two serological detection methods can be significantly useful for the control of WDV in China.
