The purpose of this study is to detect the plasmid copies encoding HBsAg in recombinant yeast Saccharomyces cerevisiae by real-time PCR, and provide the data for setting up an optimal process of manufacturing hepatiti...The purpose of this study is to detect the plasmid copies encoding HBsAg in recombinant yeast Saccharomyces cerevisiae by real-time PCR, and provide the data for setting up an optimal process of manufacturing hepatitis B vaccine in future. A single copy URA3 gene in the yeast genome was employed as internal control to test the plasmid copies by real-time PCR. The yeast cells carrying plasmids encoding HBsAg were cultured in regular non-feeding process and fed-batch process in shaking flasks at laboratory level and industrial fermentor. The cells at different stages of cultivation were collected and broken. Then the total DNAs of the cells were extracted and the plasmid copies were detected by real-time PCR with the method of relative quantification. The method of the real-time relative quantitative PCR used in this study was reliable with good accuracy and quickness. The plasmid copies in non-feeding and fed-batch flasks were 39.22±12.00 and 43.06±5.70, while the copies in fermentor were 96.16±21.00 and 82.50±7.78, respectively. The data show that the variation of the result is very small and the data precision is quite good. To prolong the fermentation time may increase the cell density without influence on the stability of the plasmid, and the method of relative quantification can also be applied to test the copy number of interest target gene in any host cell with certain known copy gene.展开更多
Prorocentrum donghaiense is a dinoflagellate that is widely distributed in the East China Sea and has become increasingly involved in Harmful Algal Blooms (HABs). Therefore, it is necessary to study this dinoflagellat...Prorocentrum donghaiense is a dinoflagellate that is widely distributed in the East China Sea and has become increasingly involved in Harmful Algal Blooms (HABs). Therefore, it is necessary to study this dinoflagellate to monitor HABs. In this study, 13 pairs of primers specific to P. donghaiense (within its internal transcribed spacer (ITS) regions) were designed for SYBR Green I real-time PCR. As the SYBR Green I real-time PCR could not identify P. donghaiense in a specific manner, a Taqman real-time PCR method was developed by designing a set of specific primers and a Taqman probe. A 10-fold serial dilution of recombinant plasmid containing ITS regions of P. donghaiense was prepared as standard samples and the standard curve was established. Additionally, we quantified the genomic DNA in P. donghaiense cells and utilized this DNA to prepare another 10-fold serial dilution of standard sample and accordingly set up the standard curve. The mathematic correlation between the cell number and its corresponding plasmid copy number was also established. In order to test the efficiency of the real-time PCR method, laboratory samples and P. donghaiense HAB field samples were employed for identification and quantitative analysis. As to laboratory samples, as few as 102 cells of P. donghaiense could be quantified precisely utilizing both centrifugation and filtration techniques. The quantification results from field samples by real-time PCR were highly similar to those by light microscopy. In conclusion, the real-time PCR could be applied to identify and quantify P. donghaiense in HABs.展开更多
L-arabinose isomerase (L-AI) is the key enzyme for D-galactose isomerization of D-tagatose by biological method. In this research, Lactobacillus plantarum WU14 with high D-tagatose yield was identified as Lactobacillu...L-arabinose isomerase (L-AI) is the key enzyme for D-galactose isomerization of D-tagatose by biological method. In this research, Lactobacillus plantarum WU14 with high D-tagatose yield was identified as Lactobacillus plantarum was isolated from the number of lactic acid bacteria from pickled vegetables. The crude L-arabinose isomerase activity of Lactobacillus plantarum WU14 with high D-tagatose yield was 13.95 U/mL under the optimal temperature 60°C, pH 7.17 and substrate concentration 0.8 mol/L, and the conversion rate of 56.12% could be gained after 28 hours. Protein structure and specific of L-Arabinose Isomerase of Lactobacillus plantarum WU14 were researched. The results showed that L-arabinose isomerase is mainly composed of alpha helix and random coil. Then the recombinant L-AI gene was inserted into the food-grade expression vector pRNA48 and expressed in L. lactis NZ9000 successfully. The target protein expression reached the maximum amount when the induced concentration of nisin reaches 30 ng/mL after 12 h. And the crude enzyme activity of recombinant bacteria reached 6.21 U/mL under 60°C. Otherwise the optimal conversion rate recombinant of L. lactis NZ9000/pRNA48-L-AI can reach 39.21% under the temperature of 50°C, pH 7.17 and D-galactose concentration was 0.6 mol/L.展开更多
A simple recombinant PCR method was used to delete the dszB gene responsible for the slowest step of the Dsz pathway and allow the accumulation of hydroxyphenyl benzene sulfinate (HPBS) in the recombinant E. coli. Usi...A simple recombinant PCR method was used to delete the dszB gene responsible for the slowest step of the Dsz pathway and allow the accumulation of hydroxyphenyl benzene sulfinate (HPBS) in the recombinant E. coli. Using GC/MS, HPBS accumulation was confirmed. The recombinant E. coli could also desulfurize Cx-DBT to corresponding Cx-HPBS. The result gave a new insight to BDS process and explored a new method to obtain valuable surfactants from cheap raw materials.展开更多
文摘The purpose of this study is to detect the plasmid copies encoding HBsAg in recombinant yeast Saccharomyces cerevisiae by real-time PCR, and provide the data for setting up an optimal process of manufacturing hepatitis B vaccine in future. A single copy URA3 gene in the yeast genome was employed as internal control to test the plasmid copies by real-time PCR. The yeast cells carrying plasmids encoding HBsAg were cultured in regular non-feeding process and fed-batch process in shaking flasks at laboratory level and industrial fermentor. The cells at different stages of cultivation were collected and broken. Then the total DNAs of the cells were extracted and the plasmid copies were detected by real-time PCR with the method of relative quantification. The method of the real-time relative quantitative PCR used in this study was reliable with good accuracy and quickness. The plasmid copies in non-feeding and fed-batch flasks were 39.22±12.00 and 43.06±5.70, while the copies in fermentor were 96.16±21.00 and 82.50±7.78, respectively. The data show that the variation of the result is very small and the data precision is quite good. To prolong the fermentation time may increase the cell density without influence on the stability of the plasmid, and the method of relative quantification can also be applied to test the copy number of interest target gene in any host cell with certain known copy gene.
基金supported by the National Basic Research Program of China (973 Program) (No.2011CB403602)the National High Technology Research and Development Program of China (863 Program) (No.2007AA09200111)the National Marine Public Welfare Research Project (201205031-02)
文摘Prorocentrum donghaiense is a dinoflagellate that is widely distributed in the East China Sea and has become increasingly involved in Harmful Algal Blooms (HABs). Therefore, it is necessary to study this dinoflagellate to monitor HABs. In this study, 13 pairs of primers specific to P. donghaiense (within its internal transcribed spacer (ITS) regions) were designed for SYBR Green I real-time PCR. As the SYBR Green I real-time PCR could not identify P. donghaiense in a specific manner, a Taqman real-time PCR method was developed by designing a set of specific primers and a Taqman probe. A 10-fold serial dilution of recombinant plasmid containing ITS regions of P. donghaiense was prepared as standard samples and the standard curve was established. Additionally, we quantified the genomic DNA in P. donghaiense cells and utilized this DNA to prepare another 10-fold serial dilution of standard sample and accordingly set up the standard curve. The mathematic correlation between the cell number and its corresponding plasmid copy number was also established. In order to test the efficiency of the real-time PCR method, laboratory samples and P. donghaiense HAB field samples were employed for identification and quantitative analysis. As to laboratory samples, as few as 102 cells of P. donghaiense could be quantified precisely utilizing both centrifugation and filtration techniques. The quantification results from field samples by real-time PCR were highly similar to those by light microscopy. In conclusion, the real-time PCR could be applied to identify and quantify P. donghaiense in HABs.
文摘L-arabinose isomerase (L-AI) is the key enzyme for D-galactose isomerization of D-tagatose by biological method. In this research, Lactobacillus plantarum WU14 with high D-tagatose yield was identified as Lactobacillus plantarum was isolated from the number of lactic acid bacteria from pickled vegetables. The crude L-arabinose isomerase activity of Lactobacillus plantarum WU14 with high D-tagatose yield was 13.95 U/mL under the optimal temperature 60°C, pH 7.17 and substrate concentration 0.8 mol/L, and the conversion rate of 56.12% could be gained after 28 hours. Protein structure and specific of L-Arabinose Isomerase of Lactobacillus plantarum WU14 were researched. The results showed that L-arabinose isomerase is mainly composed of alpha helix and random coil. Then the recombinant L-AI gene was inserted into the food-grade expression vector pRNA48 and expressed in L. lactis NZ9000 successfully. The target protein expression reached the maximum amount when the induced concentration of nisin reaches 30 ng/mL after 12 h. And the crude enzyme activity of recombinant bacteria reached 6.21 U/mL under 60°C. Otherwise the optimal conversion rate recombinant of L. lactis NZ9000/pRNA48-L-AI can reach 39.21% under the temperature of 50°C, pH 7.17 and D-galactose concentration was 0.6 mol/L.
文摘A simple recombinant PCR method was used to delete the dszB gene responsible for the slowest step of the Dsz pathway and allow the accumulation of hydroxyphenyl benzene sulfinate (HPBS) in the recombinant E. coli. Using GC/MS, HPBS accumulation was confirmed. The recombinant E. coli could also desulfurize Cx-DBT to corresponding Cx-HPBS. The result gave a new insight to BDS process and explored a new method to obtain valuable surfactants from cheap raw materials.
