This review chronicles the development of the plant binary vectors of Ti plasmid in Agrobacterium tumefaciens during the last 30 years. A binary vector strategy was designed in 1983 to separate the T-DNA region in a s...This review chronicles the development of the plant binary vectors of Ti plasmid in Agrobacterium tumefaciens during the last 30 years. A binary vector strategy was designed in 1983 to separate the T-DNA region in a small plasmid from the virulence genes in avirulent T-DNA-less Ti plasmid. The small plant vectors with the T-DNA region have been simply now called binary Ti vectors. A binary Ti vector consist of a broad host-range replicon for propagation in A. tumeraciens, an antibiotic resistance gene for bacterial selection and the T-DNA region that would be transferred to the plant genome via the bacterial virulence machinery. The T-DNA region delimited by the right and left border sequences contains an antibiotic resistance gene for plant selection, reporter gene, and/or any genes of interest. The ColEI replicon was also added to the plasmid backbone to enhance the propagation in Escherichia coli. A general trend in the binary vector development has been to increase the plasmid stability during a long co-cultivation period of A. tumefaciens with the target host plant tissues. A second trend is to understand the molecular mechanism of broad host-range replication, and to use it to reduce the size of plasmid for ease in cloning and for higher plasmid yield in E. coli. The broad host-range replicon of VS1 was shown to be a choice of replicon over those of pRK2, pRi and pSA because of the superior stability and of small well-defined replicon. Newly developed plant binary vectors pLSU has the small size of plasmid backbone (4566 bp) consisting of VS1 replicon (2654 bp), ColE1 replicon (715 bp), a bacterial kanamycin (999 bp) or tetracycline resistance gene, and the T-DNA region (152 bp).展开更多
目前心电图诊断左心房肥大一般以 P 波的时间为标准,但阳性率较低。近年有人提出 PV1终末电势（简写为 PTF-V1）负值增大与左房肥大或扩大有关。我们将本院1977年至1979年所有经手术、X 线和临床确诊有左心房肥大的风湿性心脏病患者86...目前心电图诊断左心房肥大一般以 P 波的时间为标准,但阳性率较低。近年有人提出 PV1终末电势（简写为 PTF-V1）负值增大与左房肥大或扩大有关。我们将本院1977年至1979年所有经手术、X 线和临床确诊有左心房肥大的风湿性心脏病患者86例窦性心律的心电图测量其 PTF-V1,与其出现二尖瓣型 P 波阳性率进行比较,同时与120例正常人心电图作对照分析,讨论左房肥大的心电图诊断。展开更多
文摘This review chronicles the development of the plant binary vectors of Ti plasmid in Agrobacterium tumefaciens during the last 30 years. A binary vector strategy was designed in 1983 to separate the T-DNA region in a small plasmid from the virulence genes in avirulent T-DNA-less Ti plasmid. The small plant vectors with the T-DNA region have been simply now called binary Ti vectors. A binary Ti vector consist of a broad host-range replicon for propagation in A. tumeraciens, an antibiotic resistance gene for bacterial selection and the T-DNA region that would be transferred to the plant genome via the bacterial virulence machinery. The T-DNA region delimited by the right and left border sequences contains an antibiotic resistance gene for plant selection, reporter gene, and/or any genes of interest. The ColEI replicon was also added to the plasmid backbone to enhance the propagation in Escherichia coli. A general trend in the binary vector development has been to increase the plasmid stability during a long co-cultivation period of A. tumefaciens with the target host plant tissues. A second trend is to understand the molecular mechanism of broad host-range replication, and to use it to reduce the size of plasmid for ease in cloning and for higher plasmid yield in E. coli. The broad host-range replicon of VS1 was shown to be a choice of replicon over those of pRK2, pRi and pSA because of the superior stability and of small well-defined replicon. Newly developed plant binary vectors pLSU has the small size of plasmid backbone (4566 bp) consisting of VS1 replicon (2654 bp), ColE1 replicon (715 bp), a bacterial kanamycin (999 bp) or tetracycline resistance gene, and the T-DNA region (152 bp).
文摘目前心电图诊断左心房肥大一般以 P 波的时间为标准,但阳性率较低。近年有人提出 PV1终末电势（简写为 PTF-V1）负值增大与左房肥大或扩大有关。我们将本院1977年至1979年所有经手术、X 线和临床确诊有左心房肥大的风湿性心脏病患者86例窦性心律的心电图测量其 PTF-V1,与其出现二尖瓣型 P 波阳性率进行比较,同时与120例正常人心电图作对照分析,讨论左房肥大的心电图诊断。
