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
Dramatic decrease of sugar uptake is a general phenomenon in Streptomyces at stationary phase,when antibiotics are extensively produced.Milbemycins produced by Streptomyces bingchenggensis are a group of valuable macr...Dramatic decrease of sugar uptake is a general phenomenon in Streptomyces at stationary phase,when antibiotics are extensively produced.Milbemycins produced by Streptomyces bingchenggensis are a group of valuable macrolide biopesticides,while the low yield and titer impede their broad applications in agricultural field.Considering that inadequate sugar uptake generally hinders titer improvement of desired products,we mined the underlying sugar uptake systems and fine-tuned their expression in this work.First,we screened the candidates at both genomic and transcriptomic level in S.bingchenggensis.Then,two ATP-binding cassette transporters named TP2 and TP5 were characterized to improve milbemycin titer and yield significantly.Next,the appropriate native temporal promoters were selected and used to tune the expression of TP2 and TP5,resulting in a maximal milbemycin A3/A4 titer increase by 36.9%to 3321 mg/L.Finally,TP2 and TP5 were broadly finetuned in another two macrolide biopesticide producers Streptomyces avermitilis and Streptomyces cyaneogriseus,leading to a maximal titer improvement of 34.1%and 52.6%for avermectin B1a and nemadectin,respectively.This work provides useful transporter tools and corresponding engineering strategy for Streptomyces.展开更多
目的:探讨不同驱梅治疗时机对妊娠期梅毒患者妊娠结局,母婴快速血浆反应素试验(RPR)结果,新生儿Apgar评分以及胎传梅毒的影响。方法:选择甘肃省第二人民医院与玛曲县人民医院2019年1月至2021年12月收治的100例妊娠期梅毒患者作为研究对...目的:探讨不同驱梅治疗时机对妊娠期梅毒患者妊娠结局,母婴快速血浆反应素试验(RPR)结果,新生儿Apgar评分以及胎传梅毒的影响。方法:选择甘肃省第二人民医院与玛曲县人民医院2019年1月至2021年12月收治的100例妊娠期梅毒患者作为研究对象,按照接受驱梅治疗时机的不同分成3组,其中早期组(孕<12周)38例,中期组(孕12~27周)32例,晚期组(孕≥28周)30例。比较3组不良妊娠结局情况、母婴RPR滴度、新生儿出生后1 min和5 min的Apgar评分及新生儿胎传梅毒发病率。结果:早期组、中期组和晚期组的不良妊娠结局发生率分别为7.89%(3/38)、34.38%(11/32)和53.33%(16/30),其中早期组不良妊娠结局发生率显著低于中期组和晚期组(P<0.05)。早期组和中期组妊娠期患者RPR滴度<1∶8的比率均显著高于晚期组(P<0.05);早期组新生儿RPR滴度<1∶8的比率显著高于中期组和晚期组(P<0.05)。早期组新生儿出生后1 min和5 min Apgar评分均显著高于中期组和晚期组(P<0.05);中期组新生儿出生后1 min和5 min Apgar评分均显著高于晚期组(P<0.05)。早期组、中期组及晚期组胎传梅毒发生率分别为0(0/38)、6.25%(2/32)及26.67%(8/30),早期组和中期组胎传梅毒发生率均显著低于晚期组,差异有统计学意义(P<0.05)。结论:妊娠期梅毒患者在孕早期进行驱梅治疗可有效减少不良妊娠结局、降低母婴RPR滴度,并能有效阻断梅毒垂直传播,降低胎传梅毒的发生风险。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.
基金This work was financially supported by National Natural Science Foundation of China(Grant Nos:31772242,31972348,and 31672092).
文摘Dramatic decrease of sugar uptake is a general phenomenon in Streptomyces at stationary phase,when antibiotics are extensively produced.Milbemycins produced by Streptomyces bingchenggensis are a group of valuable macrolide biopesticides,while the low yield and titer impede their broad applications in agricultural field.Considering that inadequate sugar uptake generally hinders titer improvement of desired products,we mined the underlying sugar uptake systems and fine-tuned their expression in this work.First,we screened the candidates at both genomic and transcriptomic level in S.bingchenggensis.Then,two ATP-binding cassette transporters named TP2 and TP5 were characterized to improve milbemycin titer and yield significantly.Next,the appropriate native temporal promoters were selected and used to tune the expression of TP2 and TP5,resulting in a maximal milbemycin A3/A4 titer increase by 36.9%to 3321 mg/L.Finally,TP2 and TP5 were broadly finetuned in another two macrolide biopesticide producers Streptomyces avermitilis and Streptomyces cyaneogriseus,leading to a maximal titer improvement of 34.1%and 52.6%for avermectin B1a and nemadectin,respectively.This work provides useful transporter tools and corresponding engineering strategy for Streptomyces.
文摘目的:探讨不同驱梅治疗时机对妊娠期梅毒患者妊娠结局,母婴快速血浆反应素试验(RPR)结果,新生儿Apgar评分以及胎传梅毒的影响。方法:选择甘肃省第二人民医院与玛曲县人民医院2019年1月至2021年12月收治的100例妊娠期梅毒患者作为研究对象,按照接受驱梅治疗时机的不同分成3组,其中早期组(孕<12周)38例,中期组(孕12~27周)32例,晚期组(孕≥28周)30例。比较3组不良妊娠结局情况、母婴RPR滴度、新生儿出生后1 min和5 min的Apgar评分及新生儿胎传梅毒发病率。结果:早期组、中期组和晚期组的不良妊娠结局发生率分别为7.89%(3/38)、34.38%(11/32)和53.33%(16/30),其中早期组不良妊娠结局发生率显著低于中期组和晚期组(P<0.05)。早期组和中期组妊娠期患者RPR滴度<1∶8的比率均显著高于晚期组(P<0.05);早期组新生儿RPR滴度<1∶8的比率显著高于中期组和晚期组(P<0.05)。早期组新生儿出生后1 min和5 min Apgar评分均显著高于中期组和晚期组(P<0.05);中期组新生儿出生后1 min和5 min Apgar评分均显著高于晚期组(P<0.05)。早期组、中期组及晚期组胎传梅毒发生率分别为0(0/38)、6.25%(2/32)及26.67%(8/30),早期组和中期组胎传梅毒发生率均显著低于晚期组,差异有统计学意义(P<0.05)。结论:妊娠期梅毒患者在孕早期进行驱梅治疗可有效减少不良妊娠结局、降低母婴RPR滴度,并能有效阻断梅毒垂直传播,降低胎传梅毒的发生风险。
