| 摘要 |
PCT No. PCT/FI95/00017 Sec. 371 Date Sep. 15, 1995 Sec. 102(e) Date Sep. 15, 1995 PCT Filed Jan. 17, 1995 PCT Pub. No. WO95/19446 PCT Pub. Date Jul. 20, 1995The invention relates to a method for determining a metal present in a sample, in which method a) a recombinant DNA plasmid the copy number of which is under the control of a promoter regulatable by the metal is transferred into the cell, or a recombinant DNA plasmid the copy number of which can be varied between 1 and 2000/cell is transferred into the cell, and the plasmid contains as a marker protein a DNA sequence coding for a virus, procaryotic cell or eucaryotic cell protein or for a portion thereof essential for its biological activity, the expression of the DNA sequence being under the control of a promoter regulatable by the metal and being controlled by negative and/or positive feedback; b) the cell containing the recombinant DNA plasmid is contacted with a metal-containing sample; c) the metal is allowed to affect for a suitable time the cell which contains the recombinant DNA plasmid, whereafter the amount of recombinant DNA plasmid or the amount of protein encoded by it is determined by either physical or chemical means; d) the amount of recombinant DNA plasmid or the protein encoded by it is compared by chemical or physical means to a control test in which metal was not present and/or it was present in a known amount in a reaction, whereby the presence and/or amount of the metal can be determined.
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