The method of gene transfer into corneal endothelium was investigated to provide a foundation for the study of TGF-β1 gene transfer to inhibit corneal graft rejection.Two days after direct injection of p MAM TGF-β...The method of gene transfer into corneal endothelium was investigated to provide a foundation for the study of TGF-β1 gene transfer to inhibit corneal graft rejection.Two days after direct injection of p MAM TGF-β1 mediated by liposom e into the anterior cham ber of rabbits,one half of corneas were made into paraffin slides and the endothelial layer was carefully torn from the other half to make a single layer slide of endothelia.By means of im munohistochemical technique, the plasmid p MAM TGF- β1 expression product TGF- β1 in the endothelia was detected.Specific TGF- β1 expression was positive in the endothelia on both the paraffin slide and the single layer slide.The results showed that by direct injection into the anterior cham ber,foreign plasmid DNA could be transferred into the endothelia and its expression was obtained.This may provide a foun- dation for further study on TGF-β1 participating in local induction of corneal imm une tolerance.展开更多
An extensively drug-resistant(XDR)Escherichia coli strain 258E was isolated from an anal swab sample of a chicken farm of Anhui province in China.Genomic analyses indicated that the strain 258E harbors an incompatibil...An extensively drug-resistant(XDR)Escherichia coli strain 258E was isolated from an anal swab sample of a chicken farm of Anhui province in China.Genomic analyses indicated that the strain 258E harbors an incompatibility group N(IncN)plasmid pEC258-3,which co-produces bla_(CTX-M-3),bla_(KPC-2),bla_(TEM-1B),qnrS1,aac(6')-Ib-cr,dfrA14,arr-3,and aac(6')-Ib3.Multiple genome arrangement analyses indicated that pEC258-3 is highly homologous with pCRKP-1-KPC discovered in Klebsiella pneumoniae from a patient.Furthermore,conjugation experiments proved that plasmid pEC258-3 can be transferred horizontally and may pose a significant potential threat in animals,community and hospital settings.展开更多
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
基金This project was supported by a grant from the NaturalSciences Foundation of Hubei Province(No.97J0 70 )
文摘The method of gene transfer into corneal endothelium was investigated to provide a foundation for the study of TGF-β1 gene transfer to inhibit corneal graft rejection.Two days after direct injection of p MAM TGF-β1 mediated by liposom e into the anterior cham ber of rabbits,one half of corneas were made into paraffin slides and the endothelial layer was carefully torn from the other half to make a single layer slide of endothelia.By means of im munohistochemical technique, the plasmid p MAM TGF- β1 expression product TGF- β1 in the endothelia was detected.Specific TGF- β1 expression was positive in the endothelia on both the paraffin slide and the single layer slide.The results showed that by direct injection into the anterior cham ber,foreign plasmid DNA could be transferred into the endothelia and its expression was obtained.This may provide a foun- dation for further study on TGF-β1 participating in local induction of corneal imm une tolerance.
基金the National Key Research and Development Program of China(2018YFE0192600)the Shanghai Agriculture Applied Technology Development Program,China(T20200104)+1 种基金the Fundamental Research Funds for the Central Universities,China(2020JB05)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-ZDRW202203).
文摘An extensively drug-resistant(XDR)Escherichia coli strain 258E was isolated from an anal swab sample of a chicken farm of Anhui province in China.Genomic analyses indicated that the strain 258E harbors an incompatibility group N(IncN)plasmid pEC258-3,which co-produces bla_(CTX-M-3),bla_(KPC-2),bla_(TEM-1B),qnrS1,aac(6')-Ib-cr,dfrA14,arr-3,and aac(6')-Ib3.Multiple genome arrangement analyses indicated that pEC258-3 is highly homologous with pCRKP-1-KPC discovered in Klebsiella pneumoniae from a patient.Furthermore,conjugation experiments proved that plasmid pEC258-3 can be transferred horizontally and may pose a significant potential threat in animals,community and hospital settings.
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).
