Copper-induced changes in the urea uptake and urease activity have been investigated in the cyanobacteria Anabaena doliolum and Anacystis nidulans. Copper, at and above 5 μmol/L concentration, inhibited urea uptake a...Copper-induced changes in the urea uptake and urease activity have been investigated in the cyanobacteria Anabaena doliolum and Anacystis nidulans. Copper, at and above 5 μmol/L concentration, inhibited urea uptake and urease activity systems in both the cyanobacteria in a concentration dependent manner. However, the urea uptake and urease activity systems in A. nidulans appeared slightly more tolerant to copper than that of A.doliolum. The inhibitory effect of copper on urea uptake and urease activity was mitigated by sulphur containing amino acids (cystine and cysteine), however, methionine could not do so, indicating the involvement of sulfhydryl (-SH) groups in the assimilation of urea in cyanobacteria展开更多
The copper-regulated gene expression system has been developed to control spacial and temporal expression of transgene in plant. It comprises two parts: (1) ace I gene encoding copper-responsive transcription factor u...The copper-regulated gene expression system has been developed to control spacial and temporal expression of transgene in plant. It comprises two parts: (1) ace I gene encoding copper-responsive transcription factor under the control of a constitutive or organ-specific promoter, and (2) a gene of interest under the control of a chimeric promoter consisting of the CaMV 35S (-90 to +8) promoter linked to the metal responsive element (MRE) carrying activating copper-metallothionein expression (ACE1)-binding sites. Here, the effectiveness of two different ACE1-binding cis -elements which derive from 5'-regulatory region of yeast metallothionein gene was investigated in transgenic tobacco (Nicotiana tabacum L. cv. W38). The results revealed that the MRE (-210 to -126) could increase the system inducibility by 50% - 100% compared with the previously reported MRE (-148 to -105). It is potential to use the copper-inducible system to control valuable gene traits in plant biotechnology.展开更多
A copper-inducible, Cre-loxP recombination-mediated DNA excision system has been developed in transgenic tobacco plants. The copper inducible system derived from yeast was used for the control of the expression of the...A copper-inducible, Cre-loxP recombination-mediated DNA excision system has been developed in transgenic tobacco plants. The copper inducible system derived from yeast was used for the control of the expression of the Cre recombinase. Upon copper induction, the GVS reporter gene expression unit flanked by two direct lox sites was excised from the transgenic tobacco genome. Quantitative fluorometric GUS assays, Northern blot and PCR analyses showed a high-efficient, copper-dependent and Cre-loxP mediated DNA recombination in all the tested transgenic lines. The copper inducible foreign gene excision might be of great potential in genetic control of transgenic crops.展开更多
文摘Copper-induced changes in the urea uptake and urease activity have been investigated in the cyanobacteria Anabaena doliolum and Anacystis nidulans. Copper, at and above 5 μmol/L concentration, inhibited urea uptake and urease activity systems in both the cyanobacteria in a concentration dependent manner. However, the urea uptake and urease activity systems in A. nidulans appeared slightly more tolerant to copper than that of A.doliolum. The inhibitory effect of copper on urea uptake and urease activity was mitigated by sulphur containing amino acids (cystine and cysteine), however, methionine could not do so, indicating the involvement of sulfhydryl (-SH) groups in the assimilation of urea in cyanobacteria
文摘The copper-regulated gene expression system has been developed to control spacial and temporal expression of transgene in plant. It comprises two parts: (1) ace I gene encoding copper-responsive transcription factor under the control of a constitutive or organ-specific promoter, and (2) a gene of interest under the control of a chimeric promoter consisting of the CaMV 35S (-90 to +8) promoter linked to the metal responsive element (MRE) carrying activating copper-metallothionein expression (ACE1)-binding sites. Here, the effectiveness of two different ACE1-binding cis -elements which derive from 5'-regulatory region of yeast metallothionein gene was investigated in transgenic tobacco (Nicotiana tabacum L. cv. W38). The results revealed that the MRE (-210 to -126) could increase the system inducibility by 50% - 100% compared with the previously reported MRE (-148 to -105). It is potential to use the copper-inducible system to control valuable gene traits in plant biotechnology.
基金supported by the 863 Program,China(2002AA224011 and 2001AA212161).
文摘A copper-inducible, Cre-loxP recombination-mediated DNA excision system has been developed in transgenic tobacco plants. The copper inducible system derived from yeast was used for the control of the expression of the Cre recombinase. Upon copper induction, the GVS reporter gene expression unit flanked by two direct lox sites was excised from the transgenic tobacco genome. Quantitative fluorometric GUS assays, Northern blot and PCR analyses showed a high-efficient, copper-dependent and Cre-loxP mediated DNA recombination in all the tested transgenic lines. The copper inducible foreign gene excision might be of great potential in genetic control of transgenic crops.
