Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus closely related to the human pathogens including yellow fever virus, dengue virus and West Nile virus. There are currently no effective antiviral therap...Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus closely related to the human pathogens including yellow fever virus, dengue virus and West Nile virus. There are currently no effective antiviral therapies for all of the flavivirus and only a few highly effective vaccines are licensed for human use. In this paper, the E protein domain III (DIII) of six heterologous flaviviruses (DENV1-4, WNV and JEV) was expressed in Escherichia coli successfully. The proteins were purified after a solubilization and refolding procedure, characterized by SDS-PAGE and Western blotting. Competitive inhibition showed that all recombinant flavivirus DIII proteins blocked the entry of JEV into BHK-21 cells. Further studies indicated that antibodies induced by the soluble recombinant flavivirus DIII partially protected mice against lethal JEV challenge. These results demonstrated that recombinant flavivirus DIII proteins could inhibit JEV infection competitively, and immunization with proper folding flavivirus DIII induced cross-protection against JEV infection in mice, implying a possible role of DIII for the cross-protection among flavivirus as well as its use in antigens for immunization in animal models.展开更多
Many studies have shown that fibronectin type III domain-containing protein 5(FDNC5) and brain-derived neurotrophic factor(BDNF) play vital roles in plasticity after brain injury. An enriched environment refers to an ...Many studies have shown that fibronectin type III domain-containing protein 5(FDNC5) and brain-derived neurotrophic factor(BDNF) play vital roles in plasticity after brain injury. An enriched environment refers to an environment that provides animals with multi-sensory stimulation and movement opportunities. An enriched environment has been shown to promote the regeneration of nerve cells, synapses, and blood vessels in the animal brain after cerebral ischemia;however, the exact mechanisms have not been clarified. This study aimed to determine whether an enriched environment could improve neurobehavioral functions after the experimental inducement of cerebral ischemia and whether neurobehavioral outcomes were associated with the expression of FDNC5 and BDNF. This study established ischemic mouse models using permanent middle cerebral artery occlusion(pMCAO) on the left side. On postoperative day 1, the mice were randomly assigned to either enriched environment or standard housing condition groups. Mice in the standard housing condition group were housed and fed under standard conditions. Mice in the enriched environment group were housed in a large cage, containing various toys, and fed with a standard diet. Sham-operated mice received the same procedure, but without artery occlusion, and were housed and fed under standard conditions. On postoperative days 7 and 14, a beam-walking test was used to assess coordination, balance, and spatial learning. On postoperative days 16–20, a Morris water maze test was used to assess spatial learning and memory. On postoperative day 15, the expression levels of FDNC5 and BDNF proteins in the ipsilateral cerebral cortex were analyzed by western blot assay. The results showed that compared with the standard housing condition group, the motor balance and coordination functions(based on beam-walking test scores 7 and 14 days after operation), spatial learning abilities(based on the spatial learning scores from the Morris water maze test 16–19 days after operation), and memory abilities(based on the memory scores of the Morris water maze test 20 days after operation) of the enriched environment group improved significantly. In addition, the expression levels of FDNC5 and BDNF proteins in the ipsilateral cerebral cortex increased in the enriched environment group compared with those in the standard housing condition group. Furthermore, the Pearson correlation coefficient showed that neurobehavioral functions were positively associated with the expression levels of FDNC5 and BDNF(r = 0.587 and r = 0.840, respectively). These findings suggest that an enriched environment upregulates FDNC5 protein expression in the ipsilateral cerebral cortex after cerebral ischemia, which then activates BDNF protein expression, improving neurological function. BDNF protein expression was positively correlated with improved neurological function. The experimental protocols were approved by the Institutional Animal Care and Use Committee of Fudan University, China(approval Nos. 20160858 A232, 20160860 A234) on February 24, 2016.展开更多
AIM： To find a soluble and functional recombinant receptor-binding domain of severe acute respiratory syndrome-associated coronavirus （SARS-Cov）, and to analyze its receptor binding ability. METHODS： Three fusion ...AIM： To find a soluble and functional recombinant receptor-binding domain of severe acute respiratory syndrome-associated coronavirus （SARS-Cov）, and to analyze its receptor binding ability. METHODS： Three fusion tags （glutathione S-transferase, GST; thioredoxin, Trx; maltose-binding protein, MBP）, which preferably contributes to increasing solubility and to facilitating the proper folding of heteroprotein, were used to acquire the soluble and functional expression of RBD protein in Escherichia coli （BL21（DE3） and Rosetta-gamiB （DE3） strains）. The receptor binding ability of the purified soluble RBD protein was then detected by ELISA and flow cytometry assay. RESULTS： RBD of SARS-Cov spike protein was expressed as inclusion body when fused as TrxA tag form in both BL21 （DE3） and Rosetta-gamiB （DE3） under many different cultures and induction conditions. And there was no visible expression band on SDS-PAGE when RBD was expressed as MBP tagged form. Only GST tagged RBD was soluble expressed in BL21（DE3）, and the protein was purified by AKTA Prime Chromatography system. The ELISA data showed that GST.RBD antigen had positive reaction with anti-RBD mouse monoclonal antibody 1A5. Further flow cytometry assay demonstrated the high efficiency of RBD＇s binding ability to ACE2 （angiotensin-converting enzyme 2） positive Vero E6 cell. And ACE2 was proved as a cellular receptor that meditated an initial-affinity interaction with SARS-Cov spike protein. The geometrical mean of GST and GST.RBD binding to Vero E6 cells were 77.08 and 352.73 respectively. CONCLUSION： In this paper, we get sufficient soluble N terminal GST tagged RBD protein expressed in EcoliBL21 （DE3）; data from ELISA and flow cytometry assay demonstrate that the recombinant protein is functional and binding to ACE2 positive Vero E6 cell efficiently. And the recombinant RBD derived from E.coli can be used to developing subunit vaccine to block S protein binding with receptor and to neutralizing SARS-Cov infection.展开更多
目的对病原菌Ⅲ型分泌系统(TTSS)效应蛋白在非致病菌中进行直系同源基因预测,以获得病原菌Ⅲ型分泌系统特有效应蛋白,并进一步对特有效应蛋白模体构成进行分析,旨在更深入地认识TTSS效应蛋白,为理论研究和生物学实验提供参考。方法利用...目的对病原菌Ⅲ型分泌系统(TTSS)效应蛋白在非致病菌中进行直系同源基因预测,以获得病原菌Ⅲ型分泌系统特有效应蛋白,并进一步对特有效应蛋白模体构成进行分析,旨在更深入地认识TTSS效应蛋白,为理论研究和生物学实验提供参考。方法利用彼此最佳blast方法对效应蛋白在构建的非致病性细菌蛋白质数据库中进行直系同源基因预测,并利用Inter Pro Scan对预测获得的特有效应蛋白序列进行模体搜索分析。结果在49个收集整理的致病菌Ⅲ型分泌系统效应蛋白序列中,有18个效应蛋白在非致病菌中存在直系同源基因,31个效应蛋白(即TTSS特有效应蛋白)在非致病菌中没有直系同源基因;对31个Ⅲ型分泌系统特有效应蛋白序列进行模体分析,获得了12个效应蛋白特有模体。结论 31个致病菌Ⅲ型分泌系统特有效应蛋白序列的获得,为更精确地在致病性细菌基因组内预测获得新的效应蛋白序列奠定了基础;12个效应蛋白特有模体的获得及其基因本体注释分析进一步理解了效应蛋白的作用机制。展开更多
The gene fragment coding for amino acids 281 to 395 of the E protein of DENV-2 (New Guinea C strain) was amplified by PCR, comprising Domain III (amino acids 295 to 395) of the E protein. The fragment was cloned into ...The gene fragment coding for amino acids 281 to 395 of the E protein of DENV-2 (New Guinea C strain) was amplified by PCR, comprising Domain III (amino acids 295 to 395) of the E protein. The fragment was cloned into pMD18-T vector and subcloned to expression vector pET-28a and pMAL-c2X. The recombinant plasmid pET-28a-D2EIII was transformed into E.coli BL21(DE3) and the pMAL-c2X-D2EIII was transformed into E.coli TB1. The induced recombinant proteins were purified by His-tag and MBP-tag affinity chromatography, respectively. The purified protein His-D2EIII was used to immunize rabbit three times at two-week intervals, the immunized rabbit produced high titer anti-His-D2EIII polyclonal antibody. The result of western blot indicated that the expressed fusion protein could react with the polyclonal antibody against Domain III of E protein.展开更多
基金supported by Important National Science & Technology Specific Projects (2012ZX10004403, 2012ZX10004219)National Natural Scientific Fund of China (81072675)
文摘Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus closely related to the human pathogens including yellow fever virus, dengue virus and West Nile virus. There are currently no effective antiviral therapies for all of the flavivirus and only a few highly effective vaccines are licensed for human use. In this paper, the E protein domain III (DIII) of six heterologous flaviviruses (DENV1-4, WNV and JEV) was expressed in Escherichia coli successfully. The proteins were purified after a solubilization and refolding procedure, characterized by SDS-PAGE and Western blotting. Competitive inhibition showed that all recombinant flavivirus DIII proteins blocked the entry of JEV into BHK-21 cells. Further studies indicated that antibodies induced by the soluble recombinant flavivirus DIII partially protected mice against lethal JEV challenge. These results demonstrated that recombinant flavivirus DIII proteins could inhibit JEV infection competitively, and immunization with proper folding flavivirus DIII induced cross-protection against JEV infection in mice, implying a possible role of DIII for the cross-protection among flavivirus as well as its use in antigens for immunization in animal models.
基金supported by the National Natural Science Foundation of China,Nos.81601961(to KWY),81672242(to YW)the Key Construction Projects of Shanghai Health and Family Planning on Weak Discipline,China,No.2015ZB0401(to YW)
文摘Many studies have shown that fibronectin type III domain-containing protein 5(FDNC5) and brain-derived neurotrophic factor(BDNF) play vital roles in plasticity after brain injury. An enriched environment refers to an environment that provides animals with multi-sensory stimulation and movement opportunities. An enriched environment has been shown to promote the regeneration of nerve cells, synapses, and blood vessels in the animal brain after cerebral ischemia;however, the exact mechanisms have not been clarified. This study aimed to determine whether an enriched environment could improve neurobehavioral functions after the experimental inducement of cerebral ischemia and whether neurobehavioral outcomes were associated with the expression of FDNC5 and BDNF. This study established ischemic mouse models using permanent middle cerebral artery occlusion(pMCAO) on the left side. On postoperative day 1, the mice were randomly assigned to either enriched environment or standard housing condition groups. Mice in the standard housing condition group were housed and fed under standard conditions. Mice in the enriched environment group were housed in a large cage, containing various toys, and fed with a standard diet. Sham-operated mice received the same procedure, but without artery occlusion, and were housed and fed under standard conditions. On postoperative days 7 and 14, a beam-walking test was used to assess coordination, balance, and spatial learning. On postoperative days 16–20, a Morris water maze test was used to assess spatial learning and memory. On postoperative day 15, the expression levels of FDNC5 and BDNF proteins in the ipsilateral cerebral cortex were analyzed by western blot assay. The results showed that compared with the standard housing condition group, the motor balance and coordination functions(based on beam-walking test scores 7 and 14 days after operation), spatial learning abilities(based on the spatial learning scores from the Morris water maze test 16–19 days after operation), and memory abilities(based on the memory scores of the Morris water maze test 20 days after operation) of the enriched environment group improved significantly. In addition, the expression levels of FDNC5 and BDNF proteins in the ipsilateral cerebral cortex increased in the enriched environment group compared with those in the standard housing condition group. Furthermore, the Pearson correlation coefficient showed that neurobehavioral functions were positively associated with the expression levels of FDNC5 and BDNF(r = 0.587 and r = 0.840, respectively). These findings suggest that an enriched environment upregulates FDNC5 protein expression in the ipsilateral cerebral cortex after cerebral ischemia, which then activates BDNF protein expression, improving neurological function. BDNF protein expression was positively correlated with improved neurological function. The experimental protocols were approved by the Institutional Animal Care and Use Committee of Fudan University, China(approval Nos. 20160858 A232, 20160860 A234) on February 24, 2016.
文摘AIM： To find a soluble and functional recombinant receptor-binding domain of severe acute respiratory syndrome-associated coronavirus （SARS-Cov）, and to analyze its receptor binding ability. METHODS： Three fusion tags （glutathione S-transferase, GST; thioredoxin, Trx; maltose-binding protein, MBP）, which preferably contributes to increasing solubility and to facilitating the proper folding of heteroprotein, were used to acquire the soluble and functional expression of RBD protein in Escherichia coli （BL21（DE3） and Rosetta-gamiB （DE3） strains）. The receptor binding ability of the purified soluble RBD protein was then detected by ELISA and flow cytometry assay. RESULTS： RBD of SARS-Cov spike protein was expressed as inclusion body when fused as TrxA tag form in both BL21 （DE3） and Rosetta-gamiB （DE3） under many different cultures and induction conditions. And there was no visible expression band on SDS-PAGE when RBD was expressed as MBP tagged form. Only GST tagged RBD was soluble expressed in BL21（DE3）, and the protein was purified by AKTA Prime Chromatography system. The ELISA data showed that GST.RBD antigen had positive reaction with anti-RBD mouse monoclonal antibody 1A5. Further flow cytometry assay demonstrated the high efficiency of RBD＇s binding ability to ACE2 （angiotensin-converting enzyme 2） positive Vero E6 cell. And ACE2 was proved as a cellular receptor that meditated an initial-affinity interaction with SARS-Cov spike protein. The geometrical mean of GST and GST.RBD binding to Vero E6 cells were 77.08 and 352.73 respectively. CONCLUSION： In this paper, we get sufficient soluble N terminal GST tagged RBD protein expressed in EcoliBL21 （DE3）; data from ELISA and flow cytometry assay demonstrate that the recombinant protein is functional and binding to ACE2 positive Vero E6 cell efficiently. And the recombinant RBD derived from E.coli can be used to developing subunit vaccine to block S protein binding with receptor and to neutralizing SARS-Cov infection.
文摘目的对病原菌Ⅲ型分泌系统(TTSS)效应蛋白在非致病菌中进行直系同源基因预测,以获得病原菌Ⅲ型分泌系统特有效应蛋白,并进一步对特有效应蛋白模体构成进行分析,旨在更深入地认识TTSS效应蛋白,为理论研究和生物学实验提供参考。方法利用彼此最佳blast方法对效应蛋白在构建的非致病性细菌蛋白质数据库中进行直系同源基因预测,并利用Inter Pro Scan对预测获得的特有效应蛋白序列进行模体搜索分析。结果在49个收集整理的致病菌Ⅲ型分泌系统效应蛋白序列中,有18个效应蛋白在非致病菌中存在直系同源基因,31个效应蛋白(即TTSS特有效应蛋白)在非致病菌中没有直系同源基因;对31个Ⅲ型分泌系统特有效应蛋白序列进行模体分析,获得了12个效应蛋白特有模体。结论 31个致病菌Ⅲ型分泌系统特有效应蛋白序列的获得,为更精确地在致病性细菌基因组内预测获得新的效应蛋白序列奠定了基础;12个效应蛋白特有模体的获得及其基因本体注释分析进一步理解了效应蛋白的作用机制。
文摘The gene fragment coding for amino acids 281 to 395 of the E protein of DENV-2 (New Guinea C strain) was amplified by PCR, comprising Domain III (amino acids 295 to 395) of the E protein. The fragment was cloned into pMD18-T vector and subcloned to expression vector pET-28a and pMAL-c2X. The recombinant plasmid pET-28a-D2EIII was transformed into E.coli BL21(DE3) and the pMAL-c2X-D2EIII was transformed into E.coli TB1. The induced recombinant proteins were purified by His-tag and MBP-tag affinity chromatography, respectively. The purified protein His-D2EIII was used to immunize rabbit three times at two-week intervals, the immunized rabbit produced high titer anti-His-D2EIII polyclonal antibody. The result of western blot indicated that the expressed fusion protein could react with the polyclonal antibody against Domain III of E protein.
