Advances in arsenic biosensor development – A comprehensive review

Kaur, Hardeep; Kumar, Rajesh; Babu, J. Nagendra; Mittal, Sunil

doi:10.1016/j.bios.2014.08.003

Cited by 148 publications

(82 citation statements)

References 107 publications

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“…However, in contrast to our findings, the elimination of the arsenic efflux pump did not translate into an improvement of biosensor performance. The sensitivity of our biosensors is superior to those of the majority of whole-cell arsenic sensors reported previously (30).…”

Section: Acidithiobacillus Ferrooxidansmentioning

confidence: 49%

“…A major hurdle for the successful construction of arsenic biosensors is interference with inorganic phosphate (30), which has been observed in a number of cases (50)(51)(52). We show here that both ArsR paralogues do not bind inorganic phosphate (Fig.…”

Section: Acidithiobacillus Ferrooxidansmentioning

confidence: 61%

“…The biosensors described here are characterized by very low background signals, and ␤-galactosidase activity of ϳ10 Miller units was observed in the absence of a ligand, translating into very favorable signal-tonoise ratios for arsenic measurements. The measurements conducted were based on an analyte incubation time of 3 h, which is comparable to those for most other sensors described previously (30).…”

Section: Acidithiobacillus Ferrooxidansmentioning

confidence: 93%

“…The construction of a significant number of whole-cell arsenic biosensors has been reported in the literature (7,30), which hence raises the question of why further sensors were constructed. However, most of the biosensors use E. coli as a host, whereas no biosensors using P. putida strains have been reported.…”

Section: Acidithiobacillus Ferrooxidansmentioning

confidence: 99%

“…We report here the generation of purified, recombinantly produced ArsR1 and ArsR2 and their analysis by an array of biochemical and biophysical approaches. As mentioned above, environmental arsenic monitoring is of central importance, and several ArsR-based biosensors have been described (7,30). In the second part of this work, we describe the construction of ArsR1-and ArsR2-based biosensors.…”

mentioning

confidence: 99%

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Paralogous Regulators ArsR1 and ArsR2 of Pseudomonas putida KT2440 as a Basis for Arsenic Biosensor Development

Fernández

Morel

Ramos

et al. 2016

Appl Environ Microbiol

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The remarkable metal resistance of many microorganisms is related to the presence of multiple metal resistance operons. Pseudomonas putida KT2440 can be considered a model for these microorganisms since its arsenic resistance is due to the action of proteins encoded by the two paralogous arsenic resistance operons ARS1 and ARS2. Both operons contain the genes encoding the transcriptional regulators ArsR1 and ArsR2 that control operon expression. We show here that purified ArsR1 and ArsR2 bind the trivalent salt of arsenic (arsenite) with similar affinities (~30 M), whereas no binding is observed for the pentavalent salt (arsenate). Furthermore, trivalent salts of bismuth and antimony showed binding to both paralogues. The positions of cysteines, found to bind arsenic in other homologues, indicate that ArsR1 and ArsR2 employ different modes of arsenite recognition. Both paralogues are dimeric and possess significant thermal stability. Both proteins were used to construct whole-cell, lacZ-based biosensors. Whereas responses to bismuth were negligible, significant responses were observed for arsenite, arsenate, and antimony. Biosensors based on the P. putida arsB1 arsB2 arsenic efflux pump double mutant were significantly more sensitive than biosensors based on the wild-type strain. This sensitivity enhancement by pump mutation may be a convenient strategy for the construction of other biosensors. A frequent limitation found for other arsenic biosensors was their elevated background signal and interference by inorganic phosphate. The constructed biosensors show no interference by inorganic phosphate, are characterized by a very low background signal, and were found to be suitable to analyze environmental samples. IMPORTANCE Arsenic is at the top of the priority list of hazardous compounds issued by the U.S. Agency for Toxic Substances and Disease. The reason for the stunning arsenic resistance of many microorganisms is the existence of paralogous arsenic resistance operons.Pseudomonas putida KT2440 is a model organism for such bacteria, and their duplicated ars operons and in particular their ArsR transcription regulators have been studied in depth by in vivo approaches. Here we present an analysis of both purified ArsR paralogues by different biophysical techniques, and data obtained provide valuable insight into their structure and function. Particularly insightful was the comparison of ArsR effector profiles determined by in vitro and in vivo experimentation. We also report the use of both paralogues to construct robust and highly sensitive arsenic biosensors. Our finding that the deletion of both arsenic efflux pumps significantly increases biosensor sensitivity is of general relevance in the biosensor field.A rsenic is omnipresent in nature and found in many environmental biotopes such as seawater, freshwater, soils, and rocks. It is either released through various natural processes such as weathering or hydrothermal emissions or generated by a number of anthropogenic activities such as the use of arse...

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Section: Acidithiobacillus Ferrooxidansmentioning

confidence: 49%