To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different anti...To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different antibody titers were challenged with a Nigerian isolate of virulent IBDV. Mortality rates of the different groups were plotted against their respective mean PHA antibody titers. A group with zero antibody titer had a mortality rate of 75% while those with PHA antibody titers of 185.6, 243.2, 256 and 307.2 had mortality rates of 40%, zero, zero and zero respectively. Linear equation generated for a line of best fit of the graph of mortality rates of the chicks on their IBD antibody titers gave antibody titer (X) at which mortality (Y) would be zero as 300. A mortality of 75% and the high antibody level needed to protect chicks suggest that the isolate may be a hypervirulent strain.展开更多
Candidatus Liberibacter asiaticus （CaLas）, an uncultured Gram-negative alphaproteobacterium, is the causal agent of Huanglongbing （HLB） in citrus. CaLas resides in phloem sieve tubes and has been shown to be unequ...Candidatus Liberibacter asiaticus （CaLas）, an uncultured Gram-negative alphaproteobacterium, is the causal agent of Huanglongbing （HLB） in citrus. CaLas resides in phloem sieve tubes and has been shown to be unequally distributed in different tissues. Although HLB is a disease of citrus plants, it has been demonstrated that periwinkle can serve as an experimental host of CaLas, which can be transmitted from citrus to periwinkle via the parasitic plant dodder （Cuscuta spp.）. To investigate the distribution of CaLas in various periwinkle tissues, the bacteria were transmitted from an infected periwinkle plant to healthy periwinkles by top-grafting. The movement of the inoculum and associated titer changes were observed over time in various tissues. CaLas could be detected in the leaves, main stems, and roots of infected periwinkle by conventional PCR, and in all three tissues a clear time-dependent change in CaLas titer was observed, with titer increasing soon after inoculation and then decreasing as disease symptoms became severe. The highest titer was found at 25, 35 and 35 days after inoculation in leaves, main stems and roots, respectively. The titer in leaves was much higher than in the main stems and roots at the same time point, and the spatial distribution of CaLas in the leaves, main stems and roots of infected periwinkle was uneven, similar to what has been shown in citrus. The results provide guidance for selecting the proper periwinkle tissues and sampling times for early detection of CaLas.展开更多
[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was...[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was immunized with H120 live vaccine. The group A2 was first immunized with H120 live vaccine and later boosted with ND-IB-EDS trivalent inactivated vaccine. The group B1 was used as unimmunized chal- lenge control. The group B2 was kept as unimmunized unchallenged control. The blood samples were taken prior and post-vaccination at intervals and HI tests were conducted. At the laying peak, the group A1, A2 and B1 were challenged with IBV M4t virulent strain. The clinical features and egg production of layers were monitored and recorded. [Result] After 30 d post vaccination with H120 live vaccine, the HI titer reached 4.45 log2; after 30 days boosting with ND-IB-EDS trivalent inactivated vaccine, the HI titer reached to 7.35 log2. Before challenge, HI antibody titer in group A1, A2, B1 and B2 were respectively 4.24 log2, 7.40 Iog2, 2.10 log2 and 2.10 log2. After challenge, chickens in unimmunized challenge control group B1 showed respiratory symptoms, egg production dropped by 30.9%, and they produced more soft-shelled, no-shelled or abnormal eggs. In the group A1, some chickens had light respiratory symptoms and egg production dropped by 11.7%. In the group A2, the egg production of all chickens was as normal as the group B2. [ Conclusion] When the HI titer was over 6 log2, challenge by virulent virus had no impact on egg produc- tion; when the HI titer was 5 log2, 4 log2 and less 3 log2, egg production dropped by 6.0%, 11.3% and 29.6%, respectively. Thus, the HI anti- body level in chickens has close correlation with protection against IBV challenge.展开更多
Brucellosis is an important re-emerging zoonotic disease caused by Brucella organisms. In the absence of a Differentiation of Infected from Vaccinated Animal (DIVA) assay for bovine Brucellosis, it becomes difficult t...Brucellosis is an important re-emerging zoonotic disease caused by Brucella organisms. In the absence of a Differentiation of Infected from Vaccinated Animal (DIVA) assay for bovine Brucellosis, it becomes difficult to assess whether the anti-Brucella antibody response in an animal is due to vaccination or infection. We compared the anti-Brucella antibody titers of naturally Brucellosis affected unvaccinated cows, previously vaccinated infected cows, normal healthy vaccinated cows and healthy unvaccinated calves. The titers of anti-Brucella antibodies were estimated by indirect ELISA. The mean titer (log10) was found to be 1.518 ± 0.005 in case of naturally Brucellosis affected cattle which had been vaccinated during calf hood. The mean titer in case of naturally infected cattle which had never been vaccinated was 1.5441 ± 0.005. The mean titer in healthy unaffected cattle vaccinated during calf hood was 1.504 ± 0.002 and that of unvaccinated healthy calves was 0.560 ± 0.016. It was interesting to find that the antibody titers in naturally affected cattle which had never been vaccinated were very significantly (p < 0.01) higher than those of Brucellosis affected cows which had been vaccinated during calf hood. The titer in vaccinated infected cattle was very significantly (p < 0.01) higher than that of uninfected vaccinated cows.展开更多
Cell disruption focuses on obtaining a desired bioproduct within a cell, and it is the cell wall that must be disrupted to allow access to the contents of the cell. In animal cells, the plasma membrane is the only bar...Cell disruption focuses on obtaining a desired bioproduct within a cell, and it is the cell wall that must be disrupted to allow access to the contents of the cell. In animal cells, the plasma membrane is the only barrier separating cell contents from the environment. Sound waves from sonication, a mechanical technique for cell disintegration, have been used to disrupt as well as to aggregate cells as a step towards purification of a desired bioproduct. In the present study, an improved sonication process for the high yield of Newcastle disease virus （NDV） propagated in tissue culture was described. DF-I cell was cultured in 25cm^2 T flask. When cells were about 80% confluent, a lentogenic strain of NDV （F strain） was used to infect the cell monolayer. With evident cytopathic effect, cells were subjected to cycles of freeze-thaw before sonicating with varying combinations of amplitude, temperature and time. Cells were sonicated using a water bath Sonicator, Jac Ultrasonic 1505 JEIO TECH 4 KHz. From ANOVA analysis, a significant interaction between sonication time and amplitude was observed. This also corresponds to the highest F value observed.展开更多
Objective: to study the correlation between the preeclampsia IgG antibody A(B) titer and hemolytic disease of the newborn (HDN). Methods: from February 2018 to February 2020, the clinical data of 36 pregnant women wit...Objective: to study the correlation between the preeclampsia IgG antibody A(B) titer and hemolytic disease of the newborn (HDN). Methods: from February 2018 to February 2020, the clinical data of 36 pregnant women with blood type not blood O in our hospital were retrospectively analyzed, and the IgG anti-A (B) titer was measured and the relationship with HDN was observed. Results: in 36 cases of blood O pregnant women, IgG antibody A(B) titer less than 1:64 was 41.67%, HDN production rate was 6.67%;IgG antibody A(B) titer equal to 1:64 was 19.44%, and HDN production rate was 28.57%. IgG antibody A(B) titer = 1:128 was 13.89%, and HDN production rate was 40.00%. The titer of IgG against A(B) was 1:256, which was 16.67%, and the HDN production rate was 50.00%. The titer of IgG anti-A (B) was more than or equal to 1:552, 8.33%, and the HDN production rate was 66.67%. The titer of IgG anti-A (B) was positively correlated with the HDN production rate, and the difference was very significant (P < 0.05). Conclusion: the pregnant female IgG anti-A (B) titer of blood O is closely related to HDN. The higher the IgG anti-A (B) titer is, the more people suffer from HDN. Clinical should be to IgG anti-a (B) titer high pregnant women and fetus, newborn increased observation, as early as possible to take intervention measures.展开更多
Aphids are sap-feeding plant pests that depend on their symbiotic relationships with the primary endosymbiont Buchnera aphidicola to adapt to impoverished diets. However, how the host plant affects the aphid primary s...Aphids are sap-feeding plant pests that depend on their symbiotic relationships with the primary endosymbiont Buchnera aphidicola to adapt to impoverished diets. However, how the host plant affects the aphid primary symbiont and aphid adaptation to host plant transfer are poorly known. In this study, aphid symbiont screening and genotype identification were used to establish 2 aphid strains (Rhopalosiphum maidis [Rm] and Rhopalosiphum padi [Rp] strains) containing only Buchnera without any secondary symbionts for both wheat aphid species (R. maidis and R. padi). Aphid fitness and Buchnera titers were unstable on some of these host plants after transferring to novel host plants (G1–G5), which were influenced by host plant species and generations;however, they stabilized after prolonged feeding on the same plants for 10 generations. The electropenetrography (EPG) records showed that the allocation of aphid feeding time was significantly distinct in the 6 host plants;aphids had more intracellular punctures and spent more nonprobing time on green bristlegrass which was not conducive to its growth compared with other plants. The content of soluble sugar, soluble protein, and amino acid in the leaves of the 6 host plants were also clearly separated. The correlation coefficient analysis showed that the nutrient contents of host plants had significant correlations with aphid feeding behaviors, fitness, and Buchnera titers. In the meantime, aphid fitness, and Buchnera titers were also affected by aphid feeding behaviors. Also, Buchnera titers of aphid natural populations on 6 host plants showed a visible difference. Our study deepened our understanding of the interaction among aphids, endosymbionts, and host plants, indicating that the host plant nutrient content is a predominant factor affecting aphid adaptation to their diet, initially affecting aphid feeding behaviors, and further affecting aphid fitness and Buchnera titers, which would further contribute to exploiting new available strategies for aphid control.展开更多
The study investigated the enhanced production of 2-hydroxybutyric acid(2-HBA)from threonine using a two-step whole-cell bioconversion by recombinant Escherichia coli BL21(DE3)overexpressing threonine dehydratase and ...The study investigated the enhanced production of 2-hydroxybutyric acid(2-HBA)from threonine using a two-step whole-cell bioconversion by recombinant Escherichia coli BL21(DE3)overexpressing threonine dehydratase and keto-reductase.To address the rate-limiting step posed by NADH regeneration for the keto-reductase reaction converting 2-ketobutyric acid(2-KBA)to 2-HBA,formate dehydrogenase from Candida boidinii was overexpressed under the T7 promoter,resulting in a high titer of 1015 mM and a yield of 0.70 mol/mol.Furthermore,the yield was improved by disrupting three enzymes responsible for the degradation of the intermediate(2-KBA),pyruvate-formate lyase(PflB),pyruvate oxidase(PoxB),and pyruvate dehydrogenase complex(PDHc),leading to an impressive yield of 0.99 mol/mol,closely approaching the theo-retical maximum of 1.00 mol/mol.The triple mutant,designed to prevent 2-KBA degradation,achieved a remarkable titer of 1,400 mM and volumetric productivity of 58 mmol/L/h.To the best of our knowledge,this achievement represents the highest reported titer and yield for 2-HBA production to date.展开更多
[Objectives]This study was conducted to find a convenient and reliable method for detecting the virus titer of porcine circovirus type 2(PCV2).[Methods]The reaction conditions of the immunoperoxidase monolayer assay(I...[Objectives]This study was conducted to find a convenient and reliable method for detecting the virus titer of porcine circovirus type 2(PCV2).[Methods]The reaction conditions of the immunoperoxidase monolayer assay(IPMA)method for detecting the viral titer of PCV2 were optimized,and the results were compared with those obtained by indirect immunofluorescence assay(IFA).[Results]PCV2-infected cells exhibited brownish-red staining in either the nucleus or cytoplasm when detected by IPMA,and the detection results were largely consistent with IFA detection.[Conclusions]Both IPMA and IFA methods can be effectively used for determination of PCV2 viral titer,providing reliable support for assessing viral content during PCV2 vaccine development and validating virus inactivation efficacy.展开更多
为了解我国牛肠道病毒(BEV)流行现状,为其防控提供理论依据,本试验从四川省成都市某牛场的腹泻病牛粪便样本中分离得到1株病毒,将其命名为SC-726并进行后续研究。将SC-726接种牛肾细胞(MDBK)后观察细胞病变效应(CPE),计算病毒含量,使用...为了解我国牛肠道病毒(BEV)流行现状,为其防控提供理论依据,本试验从四川省成都市某牛场的腹泻病牛粪便样本中分离得到1株病毒,将其命名为SC-726并进行后续研究。将SC-726接种牛肾细胞(MDBK)后观察细胞病变效应(CPE),计算病毒含量,使用透射电子显微镜观察该病毒的形态特征,分析其理化特性、核酸型和细胞嗜性,绘制一步生长曲线,最后对该分离株进行5′非翻译区(5′UTR)基因测序以分析其遗传演化。结果显示,SC-726分离株感染MDBK细胞后,细胞发生明显的CPE;病毒最高滴度为1×10^(6.2) TCID_(50)/0.1 m L;电镜下观察到直径约30 nm的无囊膜球形粒子,符合传统小RNA病毒形态学特征;理化特性鉴定结果显示,该分离株几乎不受有机溶剂(乙醚、氯仿)和胰蛋白酶的影响,同时具有一系列与BEV相符的特征,如耐酸、不耐强碱、热敏感;DNA抑制剂阿糖胞苷(Ara-C)对该病毒滴度无影响,判定为RNA病毒;SC-726株能够在MDBK、乳仓鼠肾细胞(BHK-21)、猪肾细胞(PK-15)、非洲绿猴胚胎肾细胞(Marc-145)和犬肾细胞(MDCK)等多种动物细胞上增殖;遗传进化分析结果显示,该分离株为F型牛肠道病毒(BEV-F)。本试验从腹泻牛粪便样本中成功分离出1株BEV-F,进一步丰富了我国BEV资料库,为该病毒病的防治提供了理论依据。展开更多
文摘To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different antibody titers were challenged with a Nigerian isolate of virulent IBDV. Mortality rates of the different groups were plotted against their respective mean PHA antibody titers. A group with zero antibody titer had a mortality rate of 75% while those with PHA antibody titers of 185.6, 243.2, 256 and 307.2 had mortality rates of 40%, zero, zero and zero respectively. Linear equation generated for a line of best fit of the graph of mortality rates of the chicks on their IBD antibody titers gave antibody titer (X) at which mortality (Y) would be zero as 300. A mortality of 75% and the high antibody level needed to protect chicks suggest that the isolate may be a hypervirulent strain.
基金supported by the earmarked fund for China Agriculture Research System (CARS-27)the Special Fund for Agro-Scientific Research in the Public Interest, China (2010003067)
文摘Candidatus Liberibacter asiaticus （CaLas）, an uncultured Gram-negative alphaproteobacterium, is the causal agent of Huanglongbing （HLB） in citrus. CaLas resides in phloem sieve tubes and has been shown to be unequally distributed in different tissues. Although HLB is a disease of citrus plants, it has been demonstrated that periwinkle can serve as an experimental host of CaLas, which can be transmitted from citrus to periwinkle via the parasitic plant dodder （Cuscuta spp.）. To investigate the distribution of CaLas in various periwinkle tissues, the bacteria were transmitted from an infected periwinkle plant to healthy periwinkles by top-grafting. The movement of the inoculum and associated titer changes were observed over time in various tissues. CaLas could be detected in the leaves, main stems, and roots of infected periwinkle by conventional PCR, and in all three tissues a clear time-dependent change in CaLas titer was observed, with titer increasing soon after inoculation and then decreasing as disease symptoms became severe. The highest titer was found at 25, 35 and 35 days after inoculation in leaves, main stems and roots, respectively. The titer in leaves was much higher than in the main stems and roots at the same time point, and the spatial distribution of CaLas in the leaves, main stems and roots of infected periwinkle was uneven, similar to what has been shown in citrus. The results provide guidance for selecting the proper periwinkle tissues and sampling times for early detection of CaLas.
文摘[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was immunized with H120 live vaccine. The group A2 was first immunized with H120 live vaccine and later boosted with ND-IB-EDS trivalent inactivated vaccine. The group B1 was used as unimmunized chal- lenge control. The group B2 was kept as unimmunized unchallenged control. The blood samples were taken prior and post-vaccination at intervals and HI tests were conducted. At the laying peak, the group A1, A2 and B1 were challenged with IBV M4t virulent strain. The clinical features and egg production of layers were monitored and recorded. [Result] After 30 d post vaccination with H120 live vaccine, the HI titer reached 4.45 log2; after 30 days boosting with ND-IB-EDS trivalent inactivated vaccine, the HI titer reached to 7.35 log2. Before challenge, HI antibody titer in group A1, A2, B1 and B2 were respectively 4.24 log2, 7.40 Iog2, 2.10 log2 and 2.10 log2. After challenge, chickens in unimmunized challenge control group B1 showed respiratory symptoms, egg production dropped by 30.9%, and they produced more soft-shelled, no-shelled or abnormal eggs. In the group A1, some chickens had light respiratory symptoms and egg production dropped by 11.7%. In the group A2, the egg production of all chickens was as normal as the group B2. [ Conclusion] When the HI titer was over 6 log2, challenge by virulent virus had no impact on egg produc- tion; when the HI titer was 5 log2, 4 log2 and less 3 log2, egg production dropped by 6.0%, 11.3% and 29.6%, respectively. Thus, the HI anti- body level in chickens has close correlation with protection against IBV challenge.
文摘Brucellosis is an important re-emerging zoonotic disease caused by Brucella organisms. In the absence of a Differentiation of Infected from Vaccinated Animal (DIVA) assay for bovine Brucellosis, it becomes difficult to assess whether the anti-Brucella antibody response in an animal is due to vaccination or infection. We compared the anti-Brucella antibody titers of naturally Brucellosis affected unvaccinated cows, previously vaccinated infected cows, normal healthy vaccinated cows and healthy unvaccinated calves. The titers of anti-Brucella antibodies were estimated by indirect ELISA. The mean titer (log10) was found to be 1.518 ± 0.005 in case of naturally Brucellosis affected cattle which had been vaccinated during calf hood. The mean titer in case of naturally infected cattle which had never been vaccinated was 1.5441 ± 0.005. The mean titer in healthy unaffected cattle vaccinated during calf hood was 1.504 ± 0.002 and that of unvaccinated healthy calves was 0.560 ± 0.016. It was interesting to find that the antibody titers in naturally affected cattle which had never been vaccinated were very significantly (p < 0.01) higher than those of Brucellosis affected cows which had been vaccinated during calf hood. The titer in vaccinated infected cattle was very significantly (p < 0.01) higher than that of uninfected vaccinated cows.
文摘Cell disruption focuses on obtaining a desired bioproduct within a cell, and it is the cell wall that must be disrupted to allow access to the contents of the cell. In animal cells, the plasma membrane is the only barrier separating cell contents from the environment. Sound waves from sonication, a mechanical technique for cell disintegration, have been used to disrupt as well as to aggregate cells as a step towards purification of a desired bioproduct. In the present study, an improved sonication process for the high yield of Newcastle disease virus （NDV） propagated in tissue culture was described. DF-I cell was cultured in 25cm^2 T flask. When cells were about 80% confluent, a lentogenic strain of NDV （F strain） was used to infect the cell monolayer. With evident cytopathic effect, cells were subjected to cycles of freeze-thaw before sonicating with varying combinations of amplitude, temperature and time. Cells were sonicated using a water bath Sonicator, Jac Ultrasonic 1505 JEIO TECH 4 KHz. From ANOVA analysis, a significant interaction between sonication time and amplitude was observed. This also corresponds to the highest F value observed.
文摘Objective: to study the correlation between the preeclampsia IgG antibody A(B) titer and hemolytic disease of the newborn (HDN). Methods: from February 2018 to February 2020, the clinical data of 36 pregnant women with blood type not blood O in our hospital were retrospectively analyzed, and the IgG anti-A (B) titer was measured and the relationship with HDN was observed. Results: in 36 cases of blood O pregnant women, IgG antibody A(B) titer less than 1:64 was 41.67%, HDN production rate was 6.67%;IgG antibody A(B) titer equal to 1:64 was 19.44%, and HDN production rate was 28.57%. IgG antibody A(B) titer = 1:128 was 13.89%, and HDN production rate was 40.00%. The titer of IgG against A(B) was 1:256, which was 16.67%, and the HDN production rate was 50.00%. The titer of IgG anti-A (B) was more than or equal to 1:552, 8.33%, and the HDN production rate was 66.67%. The titer of IgG anti-A (B) was positively correlated with the HDN production rate, and the difference was very significant (P < 0.05). Conclusion: the pregnant female IgG anti-A (B) titer of blood O is closely related to HDN. The higher the IgG anti-A (B) titer is, the more people suffer from HDN. Clinical should be to IgG anti-a (B) titer high pregnant women and fetus, newborn increased observation, as early as possible to take intervention measures.
基金funded by the programs of the China Agriculture Research System of MOF and MARA(CARS-02)the Agricultural Science and Technology Innovation Program(ASTIP)of CAAS.
文摘Aphids are sap-feeding plant pests that depend on their symbiotic relationships with the primary endosymbiont Buchnera aphidicola to adapt to impoverished diets. However, how the host plant affects the aphid primary symbiont and aphid adaptation to host plant transfer are poorly known. In this study, aphid symbiont screening and genotype identification were used to establish 2 aphid strains (Rhopalosiphum maidis [Rm] and Rhopalosiphum padi [Rp] strains) containing only Buchnera without any secondary symbionts for both wheat aphid species (R. maidis and R. padi). Aphid fitness and Buchnera titers were unstable on some of these host plants after transferring to novel host plants (G1–G5), which were influenced by host plant species and generations;however, they stabilized after prolonged feeding on the same plants for 10 generations. The electropenetrography (EPG) records showed that the allocation of aphid feeding time was significantly distinct in the 6 host plants;aphids had more intracellular punctures and spent more nonprobing time on green bristlegrass which was not conducive to its growth compared with other plants. The content of soluble sugar, soluble protein, and amino acid in the leaves of the 6 host plants were also clearly separated. The correlation coefficient analysis showed that the nutrient contents of host plants had significant correlations with aphid feeding behaviors, fitness, and Buchnera titers. In the meantime, aphid fitness, and Buchnera titers were also affected by aphid feeding behaviors. Also, Buchnera titers of aphid natural populations on 6 host plants showed a visible difference. Our study deepened our understanding of the interaction among aphids, endosymbionts, and host plants, indicating that the host plant nutrient content is a predominant factor affecting aphid adaptation to their diet, initially affecting aphid feeding behaviors, and further affecting aphid fitness and Buchnera titers, which would further contribute to exploiting new available strategies for aphid control.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.NRF-2020R1A5A1019631).
文摘The study investigated the enhanced production of 2-hydroxybutyric acid(2-HBA)from threonine using a two-step whole-cell bioconversion by recombinant Escherichia coli BL21(DE3)overexpressing threonine dehydratase and keto-reductase.To address the rate-limiting step posed by NADH regeneration for the keto-reductase reaction converting 2-ketobutyric acid(2-KBA)to 2-HBA,formate dehydrogenase from Candida boidinii was overexpressed under the T7 promoter,resulting in a high titer of 1015 mM and a yield of 0.70 mol/mol.Furthermore,the yield was improved by disrupting three enzymes responsible for the degradation of the intermediate(2-KBA),pyruvate-formate lyase(PflB),pyruvate oxidase(PoxB),and pyruvate dehydrogenase complex(PDHc),leading to an impressive yield of 0.99 mol/mol,closely approaching the theo-retical maximum of 1.00 mol/mol.The triple mutant,designed to prevent 2-KBA degradation,achieved a remarkable titer of 1,400 mM and volumetric productivity of 58 mmol/L/h.To the best of our knowledge,this achievement represents the highest reported titer and yield for 2-HBA production to date.
基金Supported by General Project of Shandong Provincial Natural Science Foundation(ZR2022MC173)Binzhou Young Science and Technology Rising Star Program(QMX2023004)Binzhou Comprehensive Experimental Station of Shandong Swine Industry Technology System Project(SDAIT-08-13).
文摘[Objectives]This study was conducted to find a convenient and reliable method for detecting the virus titer of porcine circovirus type 2(PCV2).[Methods]The reaction conditions of the immunoperoxidase monolayer assay(IPMA)method for detecting the viral titer of PCV2 were optimized,and the results were compared with those obtained by indirect immunofluorescence assay(IFA).[Results]PCV2-infected cells exhibited brownish-red staining in either the nucleus or cytoplasm when detected by IPMA,and the detection results were largely consistent with IFA detection.[Conclusions]Both IPMA and IFA methods can be effectively used for determination of PCV2 viral titer,providing reliable support for assessing viral content during PCV2 vaccine development and validating virus inactivation efficacy.
文摘为了解我国牛肠道病毒(BEV)流行现状,为其防控提供理论依据,本试验从四川省成都市某牛场的腹泻病牛粪便样本中分离得到1株病毒,将其命名为SC-726并进行后续研究。将SC-726接种牛肾细胞(MDBK)后观察细胞病变效应(CPE),计算病毒含量,使用透射电子显微镜观察该病毒的形态特征,分析其理化特性、核酸型和细胞嗜性,绘制一步生长曲线,最后对该分离株进行5′非翻译区(5′UTR)基因测序以分析其遗传演化。结果显示,SC-726分离株感染MDBK细胞后,细胞发生明显的CPE;病毒最高滴度为1×10^(6.2) TCID_(50)/0.1 m L;电镜下观察到直径约30 nm的无囊膜球形粒子,符合传统小RNA病毒形态学特征;理化特性鉴定结果显示,该分离株几乎不受有机溶剂(乙醚、氯仿)和胰蛋白酶的影响,同时具有一系列与BEV相符的特征,如耐酸、不耐强碱、热敏感;DNA抑制剂阿糖胞苷(Ara-C)对该病毒滴度无影响,判定为RNA病毒;SC-726株能够在MDBK、乳仓鼠肾细胞(BHK-21)、猪肾细胞(PK-15)、非洲绿猴胚胎肾细胞(Marc-145)和犬肾细胞(MDCK)等多种动物细胞上增殖;遗传进化分析结果显示,该分离株为F型牛肠道病毒(BEV-F)。本试验从腹泻牛粪便样本中成功分离出1株BEV-F,进一步丰富了我国BEV资料库,为该病毒病的防治提供了理论依据。
