To reveal the saddle-type dose effect relationship, we propose a radiation mutagenesis model based on maize nutrition difference resulting from heavy ion ~7Li radiation. Through irradiation mutagenesis, apparent trait...To reveal the saddle-type dose effect relationship, we propose a radiation mutagenesis model based on maize nutrition difference resulting from heavy ion ~7Li radiation. Through irradiation mutagenesis, apparent trait selection, amino acids and fatty acids content determination, and modeling, dynamic evolution from microscopic damage and repair initiation to the final macroscopic biological effects are considered simultaneously. The results show that the steady state nature is independent of evolution time and only relates to different radiation doses.Heavy ion ~7Li radiation could effectively cause maize phenotypic variation and could improve nutritional quality.This model not only gives a good fit to the experimental results on most types of amino acids and fatty acids, but also offers an adequate explanation of the experimental phenomenon underlying the saddle-type bimodal dose effect. By combining experimental results with theoretical analyses, we suggest that the synergy of the stimulus effect and momentum transfer is the main cause of the saddle-type dose effect bimodal curve. This provides an effective strategy for conducting maize germplasm innovation.展开更多
Considering the importance of a microbial strain capable of increased cellulase production, a mutant strain UP4 of Trichoderma viride was developed by ultraviolet （UV） and plasma mutation. The mutant produced a 21.0...Considering the importance of a microbial strain capable of increased cellulase production, a mutant strain UP4 of Trichoderma viride was developed by ultraviolet （UV） and plasma mutation. The mutant produced a 21.0 IU/mL FPase which was 98.1% higher than that of the parent strain Trichoderma viride ZY-1. In addition, the effect of ultraviolet and plasma mutagenesis was not merely simple superimposition of single ultraviolet mutation and single plasma mutation. Meanwhile, there appeared a capsule around some of the spores after the ultraviolet and plasma treatment, namely, the spore surface of the strain became fuzzy after ultraviolet or ultraviolet and plasma mutagenesis.展开更多
Internal solvation of protein was studied by site-directed mutagenesis, with which an intrinsically fluorescent probe,tryptophan, is inserted into the desired position inside a protein molecule for ultrafast spectrosc...Internal solvation of protein was studied by site-directed mutagenesis, with which an intrinsically fluorescent probe,tryptophan, is inserted into the desired position inside a protein molecule for ultrafast spectroscopic study. Here we review this unique method for protein dynamics research. We first introduce the frontiers of protein solvation, site-directed mutagenesis, protein stability and characteristics, and the spectroscopic methods. Then we present time-resolved spectroscopic dynamics of solvation dynamics inside cavities of active sites. The studies are carried out on a globular protein, staphylococcal nuclease. The solvation at sites inside the protein molecule＇s cavities clearly reveals characteristics of the local environment. These solvation behaviors are directly correlated to enzyme activity.展开更多
Intact pZ189 DNA was replicated in monkey kidney vero cells which had been pretreated with Nmethyl-N’-nitro-N-nitrosoguanidine (MNNG) . The mutants were selected in E. coli MBM7070 and the mutation frequencies involv...Intact pZ189 DNA was replicated in monkey kidney vero cells which had been pretreated with Nmethyl-N’-nitro-N-nitrosoguanidine (MNNG) . The mutants were selected in E. coli MBM7070 and the mutation frequencies involving mutants with unchanged electrophoretic mobilrty of their plasmid DNA were scored. When compared to the spontaneous mutation frequency. the mutation frequencies were increased by 5.8 and 2.9-fold in cells pretreated with 0. 2 and 2μmol/L MNNG, respectively. The supF genes of these mutants were sequenced. and it was found that the types of base substitution and the sites of frameshifts differed from findings in studies of spontaneous and targeted mutagenesis. The results suggest that nontargeted mutagenesis occurs in mammalian cells and may have a sequence specificity.展开更多
Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites...Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites in the GlcNAcT-V gene is the most important. Methods.Wild type of GlcNAcTV was transfected into COS7 cells and its activity was measured 48 h later. The first site (Asn 110) was mutated with sitedirected mutagenesis and transfected into COS7 cells. Results. It was found that after the cells were added tunicamycin(TM, 1 μ g/ml), the activity was 117% of the wild type. The activity of the cells with mutating GlcNAcTV was about 120% of the wild type RTPCR showed that there was no significant change in mRNA expression among the three groups. Conclusion.The Nglycosylation is important for its activity. Our results suggest that the Nlinked carbohydrates on GlcNAcTV are required for the posttranscriptional activity of the enzyme.展开更多
Objective: To study the genotoxicity and antitumor activity of a Chinese medicinal herb, Tripterygium Hypoglaucum (Level) Hutch (THH). Methods: The genotoxicity and antitumor activity of TH-H were investigated in huma...Objective: To study the genotoxicity and antitumor activity of a Chinese medicinal herb, Tripterygium Hypoglaucum (Level) Hutch (THH). Methods: The genotoxicity and antitumor activity of TH-H were investigated in human promyelocytic leukemia cells on the mutation of hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene by using single cell clone culture, two-way screening counting, multiplex PCR amplification and gel electrophoresis. Results: The results showed that different mutant spectra existed between the spontaneous mutation and induced mutation by THH. Only 7. 7% (1/13) of spontaneous mutants showed deletion mutations, whereas the induced mutants included 46.6% (27/58) deletions. Mapping of all intragenic deletion breakpoints showed a random distribution in all 9 exons, but toward the 3'-end of the HPRT gene. Deletion of exon 1 only appeared when whole gene was deleted. Deletions of exon 7/8 and 9 often showed linkage deletions (71.4%). Conclusion: THH can induce the mutation, mainly deletions, of HPRT gene in human promyelocytic leukemia cells.展开更多
Objective: To establish transgenic mouse lineages containing copies of a stably integratedpSPORT1 plasmid by microinjection into fertilized eggs and to provide an efficient animal model for studyinggene mutations in v...Objective: To establish transgenic mouse lineages containing copies of a stably integratedpSPORT1 plasmid by microinjection into fertilized eggs and to provide an efficient animal model for studyinggene mutations in vivo. Methods and Results: 2594 fertilized eggs from KM white mice were injected withpSPORT1 DNA and transferred into the oviducts of 103 pseudopregnant females. from which 237 offspringswere obtained. 40 of these offsprings were identified positive for the forgeign gene by PCR analysis and 38were reproved positive by Southern blot analysis. Finally, eight of the stout mice whose genornes were integrated with intact pSPORT1 vectors, verified by Southern blotting analysis, were chosen as founders to establish the transgenic mouse lineages. The experimental results inchoated that the pregnant rate of recipientfemales and the Positive rate of offsprings were dramatically influenced by the structure of the transgene(linearized or circular ) and the mode of egg-transfer. The integration rate of linearized transgene was significantly higher than that of the circular transgene,and female with two-side oviduct transfer of fertilized eggs waseasy to have baby mice. Conclusion: (1 ) Transgenic mouse lineages containing copies of a stably integratedPSPORT 1 plasmid were established; (2 ) The linearized transgene and two-side oviduct transfer of fertilizedeggs is more efficient in preparing transgenic mice.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.11735006the Hebei Natural Science Foundation of under Grant No.B2014209314the Hebei Science and Technology Research Project of Higher Education under Grant No.ZD2017023
文摘To reveal the saddle-type dose effect relationship, we propose a radiation mutagenesis model based on maize nutrition difference resulting from heavy ion ~7Li radiation. Through irradiation mutagenesis, apparent trait selection, amino acids and fatty acids content determination, and modeling, dynamic evolution from microscopic damage and repair initiation to the final macroscopic biological effects are considered simultaneously. The results show that the steady state nature is independent of evolution time and only relates to different radiation doses.Heavy ion ~7Li radiation could effectively cause maize phenotypic variation and could improve nutritional quality.This model not only gives a good fit to the experimental results on most types of amino acids and fatty acids, but also offers an adequate explanation of the experimental phenomenon underlying the saddle-type bimodal dose effect. By combining experimental results with theoretical analyses, we suggest that the synergy of the stimulus effect and momentum transfer is the main cause of the saddle-type dose effect bimodal curve. This provides an effective strategy for conducting maize germplasm innovation.
文摘Considering the importance of a microbial strain capable of increased cellulase production, a mutant strain UP4 of Trichoderma viride was developed by ultraviolet （UV） and plasma mutation. The mutant produced a 21.0 IU/mL FPase which was 98.1% higher than that of the parent strain Trichoderma viride ZY-1. In addition, the effect of ultraviolet and plasma mutagenesis was not merely simple superimposition of single ultraviolet mutation and single plasma mutation. Meanwhile, there appeared a capsule around some of the spores after the ultraviolet and plasma treatment, namely, the spore surface of the strain became fuzzy after ultraviolet or ultraviolet and plasma mutagenesis.
基金Project supported by the National Basic Research Program of China(Grant Nos.2013CB921904,2009CB930504,and 2013CB328700)the National Natural Science Foundation of China(Grant Nos.11074016,11121091,10934001,61177020,11134001,and 10828407)
文摘Internal solvation of protein was studied by site-directed mutagenesis, with which an intrinsically fluorescent probe,tryptophan, is inserted into the desired position inside a protein molecule for ultrafast spectroscopic study. Here we review this unique method for protein dynamics research. We first introduce the frontiers of protein solvation, site-directed mutagenesis, protein stability and characteristics, and the spectroscopic methods. Then we present time-resolved spectroscopic dynamics of solvation dynamics inside cavities of active sites. The studies are carried out on a globular protein, staphylococcal nuclease. The solvation at sites inside the protein molecule＇s cavities clearly reveals characteristics of the local environment. These solvation behaviors are directly correlated to enzyme activity.
文摘Intact pZ189 DNA was replicated in monkey kidney vero cells which had been pretreated with Nmethyl-N’-nitro-N-nitrosoguanidine (MNNG) . The mutants were selected in E. coli MBM7070 and the mutation frequencies involving mutants with unchanged electrophoretic mobilrty of their plasmid DNA were scored. When compared to the spontaneous mutation frequency. the mutation frequencies were increased by 5.8 and 2.9-fold in cells pretreated with 0. 2 and 2μmol/L MNNG, respectively. The supF genes of these mutants were sequenced. and it was found that the types of base substitution and the sites of frameshifts differed from findings in studies of spontaneous and targeted mutagenesis. The results suggest that nontargeted mutagenesis occurs in mammalian cells and may have a sequence specificity.
文摘Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites in the GlcNAcT-V gene is the most important. Methods.Wild type of GlcNAcTV was transfected into COS7 cells and its activity was measured 48 h later. The first site (Asn 110) was mutated with sitedirected mutagenesis and transfected into COS7 cells. Results. It was found that after the cells were added tunicamycin(TM, 1 μ g/ml), the activity was 117% of the wild type. The activity of the cells with mutating GlcNAcTV was about 120% of the wild type RTPCR showed that there was no significant change in mRNA expression among the three groups. Conclusion.The Nglycosylation is important for its activity. Our results suggest that the Nlinked carbohydrates on GlcNAcTV are required for the posttranscriptional activity of the enzyme.
基金Supported by National Natural Science Foundation (No. 39970650) and Chongqing Public Health Bureau Foundation (2000).
文摘Objective: To study the genotoxicity and antitumor activity of a Chinese medicinal herb, Tripterygium Hypoglaucum (Level) Hutch (THH). Methods: The genotoxicity and antitumor activity of TH-H were investigated in human promyelocytic leukemia cells on the mutation of hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene by using single cell clone culture, two-way screening counting, multiplex PCR amplification and gel electrophoresis. Results: The results showed that different mutant spectra existed between the spontaneous mutation and induced mutation by THH. Only 7. 7% (1/13) of spontaneous mutants showed deletion mutations, whereas the induced mutants included 46.6% (27/58) deletions. Mapping of all intragenic deletion breakpoints showed a random distribution in all 9 exons, but toward the 3'-end of the HPRT gene. Deletion of exon 1 only appeared when whole gene was deleted. Deletions of exon 7/8 and 9 often showed linkage deletions (71.4%). Conclusion: THH can induce the mutation, mainly deletions, of HPRT gene in human promyelocytic leukemia cells.
文摘Objective: To establish transgenic mouse lineages containing copies of a stably integratedpSPORT1 plasmid by microinjection into fertilized eggs and to provide an efficient animal model for studyinggene mutations in vivo. Methods and Results: 2594 fertilized eggs from KM white mice were injected withpSPORT1 DNA and transferred into the oviducts of 103 pseudopregnant females. from which 237 offspringswere obtained. 40 of these offsprings were identified positive for the forgeign gene by PCR analysis and 38were reproved positive by Southern blot analysis. Finally, eight of the stout mice whose genornes were integrated with intact pSPORT1 vectors, verified by Southern blotting analysis, were chosen as founders to establish the transgenic mouse lineages. The experimental results inchoated that the pregnant rate of recipientfemales and the Positive rate of offsprings were dramatically influenced by the structure of the transgene(linearized or circular ) and the mode of egg-transfer. The integration rate of linearized transgene was significantly higher than that of the circular transgene,and female with two-side oviduct transfer of fertilized eggs waseasy to have baby mice. Conclusion: (1 ) Transgenic mouse lineages containing copies of a stably integratedPSPORT 1 plasmid were established; (2 ) The linearized transgene and two-side oviduct transfer of fertilizedeggs is more efficient in preparing transgenic mice.
