[Objective] This study aimed to investigate the expression of exogenous gene in prokaryotes and eukaryotes. [Method] The expression vector pTYB2-WF harboring target gene was transformed into E. coli ER2566. IPTG was ...[Objective] This study aimed to investigate the expression of exogenous gene in prokaryotes and eukaryotes. [Method] The expression vector pTYB2-WF harboring target gene was transformed into E. coli ER2566. IPTG was employed to induce the expression of phytase gene. The expression of phytase fusion protein was detected by SDS-PAGE, and the fusion protein was further purified. Phytase gene phyA was expressed in Pichia pastoris expression system. Yeast recombinant vector pPIC9K-phyA was constructed and transformed into P. pastoris GS115 to construct engineering strain GS115-pPIC9K-phyA. [Result] Phytase protein was ex-pressed under methanol induction. Enzyme activity assay indicated that the activity of phytase was 7.3 U/ml. P. pastoris engineering strain GS115-pPIC9K-phyA was successful y constructed. [Conclusion] Methanol yeast expression mechanisms play a certain role in molecular biology and industrial applications.展开更多
Background:Forefoot strike(FFS) and rearfoot strike(RFS) runners differ in their kinematics,force loading rates,and joint loading patterns,but the timing of their muscle activation is less clear.Methods:Forty recreati...Background:Forefoot strike(FFS) and rearfoot strike(RFS) runners differ in their kinematics,force loading rates,and joint loading patterns,but the timing of their muscle activation is less clear.Methods:Forty recreational and highly trained runners ran at four speeds barefoot and shod on a motorized treadmill. "Barefoot" runners wore thin,five-toed socks and shod runners wore neutral running shoes.Subjects were instructed to run comfortably at each speed with no instructions about foot strike patterns.Results:Eleven runners landed with an FFS when barefoot and shod and eleven runners landed with an RFS when barefoot and shod.The 18remaining runners shifted from an FFS when barefoot to an RFS when shod(shifters).Shod shifters ran with a lower stride frequency and greater stride length than all other runners.All FFS runners landed with more plantarflexed ankles and more vertical lower legs at the beginning of stance compared to RFS runners.FFS runners activated their plantarflexor muscles 1 1%earlier and 10%longer than RFS runners.Conclusion:This earlier and longer relative activation of the plantarrlexors likely enhances the capacity for the passive structures of the foot and ankle to store elastic energy,and may also enhance the performance of the active muscle by increasing the storage of elastic strain energy in the cross-bridaes and activated thin.展开更多
文摘[Objective] This study aimed to investigate the expression of exogenous gene in prokaryotes and eukaryotes. [Method] The expression vector pTYB2-WF harboring target gene was transformed into E. coli ER2566. IPTG was employed to induce the expression of phytase gene. The expression of phytase fusion protein was detected by SDS-PAGE, and the fusion protein was further purified. Phytase gene phyA was expressed in Pichia pastoris expression system. Yeast recombinant vector pPIC9K-phyA was constructed and transformed into P. pastoris GS115 to construct engineering strain GS115-pPIC9K-phyA. [Result] Phytase protein was ex-pressed under methanol induction. Enzyme activity assay indicated that the activity of phytase was 7.3 U/ml. P. pastoris engineering strain GS115-pPIC9K-phyA was successful y constructed. [Conclusion] Methanol yeast expression mechanisms play a certain role in molecular biology and industrial applications.
基金the Purves Summer Research AwardSherman Fairchild Foundation+1 种基金National Science Foundation (NSF-0634592)Howard Hughes Medical Institute Undergraduate Science Program award 52006301 to Harvey Mudd College
文摘Background:Forefoot strike(FFS) and rearfoot strike(RFS) runners differ in their kinematics,force loading rates,and joint loading patterns,but the timing of their muscle activation is less clear.Methods:Forty recreational and highly trained runners ran at four speeds barefoot and shod on a motorized treadmill. "Barefoot" runners wore thin,five-toed socks and shod runners wore neutral running shoes.Subjects were instructed to run comfortably at each speed with no instructions about foot strike patterns.Results:Eleven runners landed with an FFS when barefoot and shod and eleven runners landed with an RFS when barefoot and shod.The 18remaining runners shifted from an FFS when barefoot to an RFS when shod(shifters).Shod shifters ran with a lower stride frequency and greater stride length than all other runners.All FFS runners landed with more plantarflexed ankles and more vertical lower legs at the beginning of stance compared to RFS runners.FFS runners activated their plantarflexor muscles 1 1%earlier and 10%longer than RFS runners.Conclusion:This earlier and longer relative activation of the plantarrlexors likely enhances the capacity for the passive structures of the foot and ankle to store elastic energy,and may also enhance the performance of the active muscle by increasing the storage of elastic strain energy in the cross-bridaes and activated thin.
