Heavy metal biosensor
Compositions and methods are provided for detection of certain heavy metals using bacterial whole cell biosensors.
1. A genetically modified bacterial cell comprising a polynucleotide sequence encoding a reporter protein, wherein the polynucleotide sequence is operably linked to a heavy metal regulated promoter, wherein said heavy metal regulated promoter is a promoter sequence of Caulobacter protein CC3302 (SEQ ID NO: 30).
2. The bacterial cell according to claim 1 , wherein said cell is Caulobacter crescentus.
3. The bacterial cell according to claim 1 , wherein said polynucleotide sequence encoding a reporter protein operably linked to a heavy metal regulated promoter is provided on a plasmid vector.
4. The bacterial cell according to claim 1 , wherein said reporter protein is a green fluorescent protein (GFP).
5. The bacterial cell according to claim 1 , wherein said heavy metal is uranium.
6. A method of detecting the presence of a heavy metal in a sample, the method comprising:
contacting said sample with a bacterial cell according to claim 1
incubating for a period of time sufficient to upregulate expression from said heavy metal regulated promoter, and
detecting the presence of said reporter protein.
7. The method according to claim 6 , wherein said detection is by naked eye.
8. The method according to claim 6 wherein said detection is by fluorimeter.
9. The genetically modified bacterial cell of claim 4 , wherein the promoter comprises at least one uranium specific promoter motif sequence.
10. A genetically modified bacterial cell comprising a polynucleotide sequence encoding a reporter protein, wherein the polynucleotide sequence is operably linked to a heavy metal regulated promoter, wherein the sequence of said heavy metal regulated promoter is at least 90% identical to SEQ ID NO: 30 or fragments thereof.
11. The bacterial cell of claim 10 , wherein the promoter sequence contains at least 50 nucleotides.
12. The bacterial cell of claim 10 , wherein the promoter sequence contains at least 100 nucleotides.
13. The bacterial cell of claim 10 , wherein the nucleotides 52-79 and 104-131 are present in the promoter that is at least 90% identical to SEQ ID NO: 30.
14. A genetically modified bacterial cell comprising a polynucleotide sequence encoding a reporter protein, wherein the polynucleotide sequence is operably linked to a heavy metal regulated promoter, wherein said heavy metal regulated promoter comprises a first uranium specific promoter motif sequence and a second uranium specific promoter sequence, wherein the first uranium specific motif sequence comprises SEQ ID NO: 28 and wherein the second uranium specific motif sequence comprises SEQ ID NO: 29.
15. The bacterial cell of claim 14 , wherein the promoter sequence contains at least 50 nucleotides.
16. The bacterial cell of claim 14 , wherein the promoter sequence contains at least 100 nucleotides.
17. The bacterial cell according to claim 1 , wherein said bacterial cell is a Caulobacter cell.
18. The bacterial cell according to claim 17 , wherein said polynucleotide sequence encoding a reporter protein operably linked to a heavy metal regulated promoter is integrated into the chromosome of said Caulobacter.