Sensing Antimonite and Arsenite at the Subattomole Level with Genetically Engineered Bioluminescent Bacteria

Abstract

A highly sensitive and selective optical sensing system for antimonite has been developed using genetically engineered bacteria. The basis of this system is the ability of certain bacteria to survive in environments that are contaminated with antimonite, arsenite, and arsenate. The survival is conferred to the bacteria by the ars operon, which consists of five genes that code for three structural proteins, ArsA, ArsB, and ArsC, and two regulatory proteins, ArsD and ArsR. ArsA, ArsB, and ArsC form a protein pump system that extrudes antimonite, arsenite, and arsenate once these anions reach the cytoplasm of the bacterium. A method was developed for monitoring antimonite and arsenite by using a single plasmid that incorporates the regulatory gene of the extrusion system, arsR, and the genes of bacterial luciferase, luxA and luxB. In the designed plasmid, ArsR regulates the expression of bacterial luciferase in a manner that is dependent on the concentration of antimonite and arsenite in the sample. Thus, the bioluminescence emitted by luciferase can be related to the concentration of antimonite and arsenite in the sample. Concentrations for antimonite and arsenite in the order of 10(-5) M, which corresponds to subattomole levels, can be detected. This bacterial-based sensing system is highly selective for antimonite and arsenite.

Characterization of a symbiotically effective Rhizobium resistant to arsenic: Isolated from the root nodules of Vigna mungo (L.) Hepper grown in an arsenic-contaminated field

“…The Escherichia coli chromosomal ars operon, confers resistance to arsenicals and antimonicals (Xu and Rosen, 1997). ArsR has a remarkably high affinity which could induce the ars promoter (Ramanathan et al, 1997). The degree of arsenite resistance found in this isolate might be due to the presence of the ArsR gene of the ars genetic system located in a chromosome.…”

The impacts of different long-term fertilization regimes on the bioavailability of arsenic in soil: integrating chemical approach with Escherichia coli arsRp::luc-based biosensor

“…Numerous microbial biosensors have been applied to detect the bioavailability of metal in polluted water or soil (Bontidean et al 2004;Liao et al 2006;Liu et al 2012) and reflect the toxicity of metal complex to microbes (Campbell et al 2000;Nybroe et al 2008). Similarly, several microbial biosensor-based asr operons, which were confirmed as important resistance systems for As and Antimonite (Sb) in E. coli (Ramanathan et al 1997), have been developed to detect the bioavailability of As (Liao and Ou 2005;Stocker et al 2003). Compared with chemical sequential extraction methods, microbial biosensor was a less expensive, faster, more convenient, and maneuverable tool to detect metal; what more significant is that it can reflect the actual bioavailability and toxicity of metal (Liao et al 2006;Stocker et al 2003;Van Dorst et al 2010).…”

Enhanced Arsenic Accumulation in Engineered Bacterial Cells Expressing ArsR

“…The ArsR protein contains a very specific binding site toward As(III) and can discriminate effectively against phosphate, sulfate, cobalt, and cadmium (28). ArsR has a strikingly high affinity, as even 10 Ϫ15 M As(III) could induce the ars promoter (22). Although the high affinity and specificity of ArsR have been exploited for development of whole-cell biosensors (22), no one has taken advantage of ArsR for arsenic remediation.…”

“…ArsR has a strikingly high affinity, as even 10 Ϫ15 M As(III) could induce the ars promoter (22). Although the high affinity and specificity of ArsR have been exploited for development of whole-cell biosensors (22), no one has taken advantage of ArsR for arsenic remediation. In this work, we present a new method for the selective removal of arsenic by using engineered E. coli cells overexpressing ArsR.…”