Background The characterization of the molecular determinants of metal resistance has potential biotechnological application in biosensing and bioremediation. In this context, the bacterium Thermus thermophilus HB27 is a metal tolerant thermophile containing a set of genes involved in arsenic resistance which, differently from other microbes, are not organized into a single operon. They encode the proteins: arsenate reductase, TtArsC, arsenic efflux membrane transporter, TtArsX, and transcriptional repressor, TtSmtB. Results In this work we show that the arsenic efflux protein TtArsX and the arsenic responsive transcriptional repressor TtSmtB are required to provide resistance to cadmium. We analyzed the sensitivity to Cd(II) of mutants lacking TtArsX, finding that they are more sensitive to this metal than the wild type strain. In addition, using promoter probe reporter plasmids, we show that the transcription of TtarsX is also stimulated by the presence of Cd(II) in a TtSmtB-dependent way. Actually, a regulatory circuit composed of TtSmtB and a reporter gene expressed from the TtarsX promoter responds to variation in Cd(II), As(III) and As(V) concentrations. Conclusions Our results demonstrate that the system composed by TtSmtB and TtArsX is responsible for both the arsenic and cadmium resistance in T. thermophilus. The data also support the use of T. thermophilus as a suitable chassis for the design and development of As-Cd biosensors.

Characterization of a promiscuous cadmium and arsenic resistance mechanism in Thermus thermophilus HB27 and potential application of a novel bioreporter system / Antonucci, Immacolata; Gallo, Giovanni; Limauro, Danila; Contursi, Patrizia; Luisa Ribeiro, Ana; Blesa, Alba; Berenguer, José; Bartolucci, Simonetta; Fiorentino, Gabriella. - In: MICROBIAL CELL FACTORIES. - ISSN 1475-2859. - 17:1(2018), pp. 78-86. [10.1186/s12934-018-0918-7]

Characterization of a promiscuous cadmium and arsenic resistance mechanism in Thermus thermophilus HB27 and potential application of a novel bioreporter system

Immacolata Antonucci;Giovanni Gallo;Danila Limauro;Patrizia Contursi;Simonetta Bartolucci;Gabriella Fiorentino
2018

Abstract

Background The characterization of the molecular determinants of metal resistance has potential biotechnological application in biosensing and bioremediation. In this context, the bacterium Thermus thermophilus HB27 is a metal tolerant thermophile containing a set of genes involved in arsenic resistance which, differently from other microbes, are not organized into a single operon. They encode the proteins: arsenate reductase, TtArsC, arsenic efflux membrane transporter, TtArsX, and transcriptional repressor, TtSmtB. Results In this work we show that the arsenic efflux protein TtArsX and the arsenic responsive transcriptional repressor TtSmtB are required to provide resistance to cadmium. We analyzed the sensitivity to Cd(II) of mutants lacking TtArsX, finding that they are more sensitive to this metal than the wild type strain. In addition, using promoter probe reporter plasmids, we show that the transcription of TtarsX is also stimulated by the presence of Cd(II) in a TtSmtB-dependent way. Actually, a regulatory circuit composed of TtSmtB and a reporter gene expressed from the TtarsX promoter responds to variation in Cd(II), As(III) and As(V) concentrations. Conclusions Our results demonstrate that the system composed by TtSmtB and TtArsX is responsible for both the arsenic and cadmium resistance in T. thermophilus. The data also support the use of T. thermophilus as a suitable chassis for the design and development of As-Cd biosensors.
2018
Characterization of a promiscuous cadmium and arsenic resistance mechanism in Thermus thermophilus HB27 and potential application of a novel bioreporter system / Antonucci, Immacolata; Gallo, Giovanni; Limauro, Danila; Contursi, Patrizia; Luisa Ribeiro, Ana; Blesa, Alba; Berenguer, José; Bartolucci, Simonetta; Fiorentino, Gabriella. - In: MICROBIAL CELL FACTORIES. - ISSN 1475-2859. - 17:1(2018), pp. 78-86. [10.1186/s12934-018-0918-7]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/718950
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