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
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
[ 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
血液复苏是严重失血患者的关键急救措施。血液复苏液体的选用,经历了从全血到晶体液/胶体液、晶体液联合红细胞、等比例血液成分的演进过程。近20年来,采用低效价抗体O型全血(low titer group O whole blood,LTOWB)作为血液复苏的首选...血液复苏是严重失血患者的关键急救措施。血液复苏液体的选用,经历了从全血到晶体液/胶体液、晶体液联合红细胞、等比例血液成分的演进过程。近20年来,采用低效价抗体O型全血(low titer group O whole blood,LTOWB)作为血液复苏的首选应急通用桥接复苏液,已发展成为大趋势。我们对全血在严重失血患者的应用历史和现状做一介绍,并提出我国采用LTOWB作为首选应急通用血液的进一步论证和验证研究建议。展开更多
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.
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.
文摘血液复苏是严重失血患者的关键急救措施。血液复苏液体的选用,经历了从全血到晶体液/胶体液、晶体液联合红细胞、等比例血液成分的演进过程。近20年来,采用低效价抗体O型全血(low titer group O whole blood,LTOWB)作为血液复苏的首选应急通用桥接复苏液,已发展成为大趋势。我们对全血在严重失血患者的应用历史和现状做一介绍,并提出我国采用LTOWB作为首选应急通用血液的进一步论证和验证研究建议。
