Genetically engineered bacteria: electrochemical sensing systems for antimonite and arsenite.
A bacterial sensing system that responds selectively to antimonite and arsenite has been investigated. The bacteria used in these studies have been genetically engineered to produce the enzyme beta-galactosidase in response to these ions. This is accomplished by using a plasmid that incorporates the gene for beta-galactosidase (reporter gene) under the control of the promoter of the ars operon. This plasmid also encodes for the ArsR protein, a regulatory protein of the ars operon, which, in the absence of antimonite or arsenite, restricts the expression of beta-galactosidase. In the presence of antimonite or arsenite the ArsR protein is released from the operator/ promoter region of the ars operon and beta-galactosidase is expressed. The activity of this enzyme was monitored electrochemically using p-aminophenyl beta-D-galactopyranoside as the substrate. The bacterial sensing system responds selectively to arsenite and antimonite (and to a lesser extent arsenate) and shows no significant response to phosphate, sulfate, nitrate, and carbonate.
Scott
D L
DL
Department of Chemistry, University of Kentucky, Lexington 40506-0055, USA.
Ramanathan
S
S
Shi
W
W
Rosen
B P
BP
Daunert
S
S
D000965:Antimony / Q000032:analysis*; D018053:Arsenites / Q000032:analysis*; D004563:Electrochemistry / Q000379:methods; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D005818:Genetic Engineering / Q000379:methods*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D018053:Arsenites; C061374:antimonite; D000965:Antimony; D001616:beta-Galactosidase