Rxol cloned from maize is a non-host gene resistant to bacterial leaf streak of rice. pCAMBIA1305-1 with Rxo1 was digested with Sca I and NgoM IV and the double right-border binary vector pMNDRBBin6 was digested with ...Rxol cloned from maize is a non-host gene resistant to bacterial leaf streak of rice. pCAMBIA1305-1 with Rxo1 was digested with Sca I and NgoM IV and the double right-border binary vector pMNDRBBin6 was digested with Hpa I and Xma I. pMNDRBBin6 carrying the gene Rxo1 was acquired by ligation of blunt-end and cohesive end. The results of PCR, restriction enzyme analysis and sequencing indicated that the Rxo1 gene had been cloned into pMNDRBBin6. This double right-border binary vector, named as pMNDRBBin6-Rxol, will play a role in breeding marker-free plants resistant to bacterial leaf streak of rice by genetic transformation.展开更多
At present,the aeration-assisted cutting-carrying technology is faced with complexities in the drilling of CBM multi-branch horizontal wells.For example,the aerating pressure is hardly maintained,and the borehole inst...At present,the aeration-assisted cutting-carrying technology is faced with complexities in the drilling of CBM multi-branch horizontal wells.For example,the aerating pressure is hardly maintained,and the borehole instability may happen.In view of these prominent problems,the technology of double casing tubes&a binary cycle system suitable for CBM multi-branch horizontal wells was developed according to the Venturi principle by means of parasitic tube insufflation which is used for well control simulation system.Then,a multiphase flow finite element model was established for the fluid-cutting particle system in this drilling condition.This technology was tested in field.Double-casing tubes cementing is adopted in this technology and a jet generator is installed at the bottom of the inner casing.In the process of drilling,the drilling fluid injected through double intermediate casing annulus is converted by the jet generator into a high-efficiency steering water jet,which,together with the water jet generated by the bit nozzle,increases the fluid returning rate in the inner annulus space.It is indicated from simulation results that the cutting-carrying effect is the best when the included angle between the nozzle of the jet generator and the vertical direction is 30°.Besides,the influential laws of cutting size,primary cycle volume,accessory cycle volume and drilling velocity on hole cleaning are figured out.It is concluded that this technology increases the flow rate of drilling fluid in annulus space,the returning rate of drilling fluid significantly and the cutting-carrying capacity.It is currently one of the effective hole cleaning technologies for CBM multi-branch horizontal wells where fresh water is taken as the drilling fluid.展开更多
The ＇double T-DNA＇ binary vector p13HSR which harbored two independent T-DNAs, containing hygromycin phosphotransferase gene （hpf） in one T-DNA region and three target genes （hLF, SB401, RZ10） in another T-DNA r...The ＇double T-DNA＇ binary vector p13HSR which harbored two independent T-DNAs, containing hygromycin phosphotransferase gene （hpf） in one T-DNA region and three target genes （hLF, SB401, RZ10） in another T-DNA region, was used to generate selectable marker-free transgenic rice by Agrobacterium-mediated transformation. The regenerated plants with both the three target genes and the selectable marker gene hpt were selected for anther culture. RT-PCR analysis indicated that target genes were inserted in rice genomic DNA and successfully transcribed. It took only one year to obtain double haploid selectable marker-free transgenic plants containing the three target genes with co-transformation followed by anther culture technique, and the efficiency was 12.2%. It was also noted that one or two target genes derived from the binary vector were lost in some transgenic rice plants.展开更多
文摘Rxol cloned from maize is a non-host gene resistant to bacterial leaf streak of rice. pCAMBIA1305-1 with Rxo1 was digested with Sca I and NgoM IV and the double right-border binary vector pMNDRBBin6 was digested with Hpa I and Xma I. pMNDRBBin6 carrying the gene Rxo1 was acquired by ligation of blunt-end and cohesive end. The results of PCR, restriction enzyme analysis and sequencing indicated that the Rxo1 gene had been cloned into pMNDRBBin6. This double right-border binary vector, named as pMNDRBBin6-Rxol, will play a role in breeding marker-free plants resistant to bacterial leaf streak of rice by genetic transformation.
基金supported by the National Science and Technology Major Project(No.2011ZX05061).
文摘At present,the aeration-assisted cutting-carrying technology is faced with complexities in the drilling of CBM multi-branch horizontal wells.For example,the aerating pressure is hardly maintained,and the borehole instability may happen.In view of these prominent problems,the technology of double casing tubes&a binary cycle system suitable for CBM multi-branch horizontal wells was developed according to the Venturi principle by means of parasitic tube insufflation which is used for well control simulation system.Then,a multiphase flow finite element model was established for the fluid-cutting particle system in this drilling condition.This technology was tested in field.Double-casing tubes cementing is adopted in this technology and a jet generator is installed at the bottom of the inner casing.In the process of drilling,the drilling fluid injected through double intermediate casing annulus is converted by the jet generator into a high-efficiency steering water jet,which,together with the water jet generated by the bit nozzle,increases the fluid returning rate in the inner annulus space.It is indicated from simulation results that the cutting-carrying effect is the best when the included angle between the nozzle of the jet generator and the vertical direction is 30°.Besides,the influential laws of cutting size,primary cycle volume,accessory cycle volume and drilling velocity on hole cleaning are figured out.It is concluded that this technology increases the flow rate of drilling fluid in annulus space,the returning rate of drilling fluid significantly and the cutting-carrying capacity.It is currently one of the effective hole cleaning technologies for CBM multi-branch horizontal wells where fresh water is taken as the drilling fluid.
文摘The ＇double T-DNA＇ binary vector p13HSR which harbored two independent T-DNAs, containing hygromycin phosphotransferase gene （hpf） in one T-DNA region and three target genes （hLF, SB401, RZ10） in another T-DNA region, was used to generate selectable marker-free transgenic rice by Agrobacterium-mediated transformation. The regenerated plants with both the three target genes and the selectable marker gene hpt were selected for anther culture. RT-PCR analysis indicated that target genes were inserted in rice genomic DNA and successfully transcribed. It took only one year to obtain double haploid selectable marker-free transgenic plants containing the three target genes with co-transformation followed by anther culture technique, and the efficiency was 12.2%. It was also noted that one or two target genes derived from the binary vector were lost in some transgenic rice plants.
