The Arrowhead Proteinase Inhibitor(API)gene was introduced into the protoplasts or mesophyll cells of N.tobacco by PEG-mediated.The transformed protoplasts undergoing dirrerentiation of callus and regeneration of plan...The Arrowhead Proteinase Inhibitor(API)gene was introduced into the protoplasts or mesophyll cells of N.tobacco by PEG-mediated.The transformed protoplasts undergoing dirrerentiation of callus and regeneration of plantlet have been growing into transgenic plants. Restriction endonuclease analysis of products amplificated by PCR indicates the existence of the API gene in the transformed plantlet.The extract of the leaves from the transformed plants shows trypsin inhibitory activity,which indicates the expression of the introduced API gene and the transformed plants can accumulate the inhibitor. However, the variation of the inhlbitory activity of the transformed plants reveals the importance of the integration site of the API gene in the genome.展开更多
Prehistoric projectile weapons are crucial for understanding the hunting behavior,survival strategies,and subsistence patterns of prehistoric humans.Arrowheads were the primary prehistoric projectile weapon,and here w...Prehistoric projectile weapons are crucial for understanding the hunting behavior,survival strategies,and subsistence patterns of prehistoric humans.Arrowheads were the primary prehistoric projectile weapon,and here we review the spatiotemporal distribution and changes in the morphology,quantity,and materials composition of arrowheads in the northern regions of China from the Middle and Upper Paleolithic periods to the Bronze Age,together with the factors that influenced these changes.The results reveal that primitive stone arrowheads appeared sporadically in the Middle Paleolithic period.Additionally,the“broad spectrum revolution”and microblade technology during the Upper Paleolithic promoted the regional-scale diffusion of broad and thick stone arrowheads in northern China.During the Neolithic period,relatively narrow and thin stone and bone arrowheads spread rapidly across the entire Yellow River Basin and most of northeastern China.The dominance of these two types of arrowheads alternated,during the period of 7000–5000 yr BP,the number of arrowheads peaked,possibly closely related to changes in the role of hunting(fishing and hunting)and gathering in the subsistence economy,human population size,and the emergence and development of a grinding technology.During the Bronze Age,a significant number of bronze arrowheads appeared,and the total number of arrowheads increased again,and their distribution expanded to northwestern China.The emergence of a bronze smelting technology and inter-group conflicts may have been the primary factors influencing this trend.Our results demonstrate that arrowheads were always an essential component of prehistoric tool kits.Due to technological developments in subsistence strategies,the morphology,function,and popularity of arrowheads underwent substantial changes during different periods.Therefore,a comprehensive study of prehistoric arrowheads can help better understand the subsistence patterns and processes of economic and societal development of prehistoric humans.展开更多
Affinity chromatography was used to separate two components A and B of the crystalline arrowhead proteinase inhibitor. Both A and B are double-headed and multifunctional proteinase inhibitors. Inhibitor A is capable o...Affinity chromatography was used to separate two components A and B of the crystalline arrowhead proteinase inhibitor. Both A and B are double-headed and multifunctional proteinase inhibitors. Inhibitor A is capable of inhibiting equimolarly trypsin and chymo-trypsin simultaneously, and has a weak inhibitory activity toward kallikrein; whereas inhibitor B can inhibit two molecules of trypsin simultaneously, and shows rather higher inhibitory activity toward kallikrein than inhibitor A, but its inhibitory activity toward chymo-trypsin is much weaker than that of inhibitor A. The results of chemical modification and the competitive binding of trypsin and chymotrypsin with inhibitor A showed that the two reactive sites of both inhibitors A and B are Lys and Arg residues. Among them the Lys reactive site is specific for inhibiting mainly trypsin, whereas the active domain composed of the Arg reactive site appears to be multifunctional and capable of inhibiting many different Ser proteinases. Based on the展开更多
After the reduction and carboxymethylation of disulfide bonds, arrowhead proteinase inhibitors A and B were cleaved either by proteinases or by cyanogen bromide, the fractionated and purified peptides were then subjec...After the reduction and carboxymethylation of disulfide bonds, arrowhead proteinase inhibitors A and B were cleaved either by proteinases or by cyanogen bromide, the fractionated and purified peptides were then subjected to sequencing by a gas phase automatic sequencer, the primary structures were completed by the alignment of the peptides sequenced with overlapping peptides. Both inhibitors A and B consist of 150 amino acid residues with three pairs of disulfide bonds, share 90% homology in structure, and are markedly different from all other Ser proteinase inhibitors so far known. Hence, the arrowhead inhibitor may belong to a new inhibitor family. Based on their structure characteristics, it was deduced that both their two reactive sites might be located in the positions of Lys-Ser (45-46) and Arg-Tyr-Lys (77-79), respectively. Among 13 mutated residues in inhibitors A and B, the substitution of residue Arg in position 87 of inhibitor B for residue Leu in A might be the main cause of leading to展开更多
文摘The Arrowhead Proteinase Inhibitor(API)gene was introduced into the protoplasts or mesophyll cells of N.tobacco by PEG-mediated.The transformed protoplasts undergoing dirrerentiation of callus and regeneration of plantlet have been growing into transgenic plants. Restriction endonuclease analysis of products amplificated by PCR indicates the existence of the API gene in the transformed plantlet.The extract of the leaves from the transformed plants shows trypsin inhibitory activity,which indicates the expression of the introduced API gene and the transformed plants can accumulate the inhibitor. However, the variation of the inhlbitory activity of the transformed plants reveals the importance of the integration site of the API gene in the genome.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0601-02)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2021-ct03).
文摘Prehistoric projectile weapons are crucial for understanding the hunting behavior,survival strategies,and subsistence patterns of prehistoric humans.Arrowheads were the primary prehistoric projectile weapon,and here we review the spatiotemporal distribution and changes in the morphology,quantity,and materials composition of arrowheads in the northern regions of China from the Middle and Upper Paleolithic periods to the Bronze Age,together with the factors that influenced these changes.The results reveal that primitive stone arrowheads appeared sporadically in the Middle Paleolithic period.Additionally,the“broad spectrum revolution”and microblade technology during the Upper Paleolithic promoted the regional-scale diffusion of broad and thick stone arrowheads in northern China.During the Neolithic period,relatively narrow and thin stone and bone arrowheads spread rapidly across the entire Yellow River Basin and most of northeastern China.The dominance of these two types of arrowheads alternated,during the period of 7000–5000 yr BP,the number of arrowheads peaked,possibly closely related to changes in the role of hunting(fishing and hunting)and gathering in the subsistence economy,human population size,and the emergence and development of a grinding technology.During the Bronze Age,a significant number of bronze arrowheads appeared,and the total number of arrowheads increased again,and their distribution expanded to northwestern China.The emergence of a bronze smelting technology and inter-group conflicts may have been the primary factors influencing this trend.Our results demonstrate that arrowheads were always an essential component of prehistoric tool kits.Due to technological developments in subsistence strategies,the morphology,function,and popularity of arrowheads underwent substantial changes during different periods.Therefore,a comprehensive study of prehistoric arrowheads can help better understand the subsistence patterns and processes of economic and societal development of prehistoric humans.
基金Project supported by the National Biological High-technology Foundation of China
文摘Affinity chromatography was used to separate two components A and B of the crystalline arrowhead proteinase inhibitor. Both A and B are double-headed and multifunctional proteinase inhibitors. Inhibitor A is capable of inhibiting equimolarly trypsin and chymo-trypsin simultaneously, and has a weak inhibitory activity toward kallikrein; whereas inhibitor B can inhibit two molecules of trypsin simultaneously, and shows rather higher inhibitory activity toward kallikrein than inhibitor A, but its inhibitory activity toward chymo-trypsin is much weaker than that of inhibitor A. The results of chemical modification and the competitive binding of trypsin and chymotrypsin with inhibitor A showed that the two reactive sites of both inhibitors A and B are Lys and Arg residues. Among them the Lys reactive site is specific for inhibiting mainly trypsin, whereas the active domain composed of the Arg reactive site appears to be multifunctional and capable of inhibiting many different Ser proteinases. Based on the
基金Project supported by the National Biological High-technology Foundation of China
文摘After the reduction and carboxymethylation of disulfide bonds, arrowhead proteinase inhibitors A and B were cleaved either by proteinases or by cyanogen bromide, the fractionated and purified peptides were then subjected to sequencing by a gas phase automatic sequencer, the primary structures were completed by the alignment of the peptides sequenced with overlapping peptides. Both inhibitors A and B consist of 150 amino acid residues with three pairs of disulfide bonds, share 90% homology in structure, and are markedly different from all other Ser proteinase inhibitors so far known. Hence, the arrowhead inhibitor may belong to a new inhibitor family. Based on their structure characteristics, it was deduced that both their two reactive sites might be located in the positions of Lys-Ser (45-46) and Arg-Tyr-Lys (77-79), respectively. Among 13 mutated residues in inhibitors A and B, the substitution of residue Arg in position 87 of inhibitor B for residue Leu in A might be the main cause of leading to
