title: Whole-cell arsenite biosensor using photosynthetic bacterium Rhodovulum sulfidophilum. Rhodovulum sulfidophilum as an arsenite biosensor.
abstract: An arsenite biosensor plasmid was constructed in Escherichia coli by inserting the operator/promoter region of the ars operon and the arsR gene from E. coli and the crtA gene, which is responsible for carotenoid synthesis in the photosynthetic bacterium, Rhodovulum sulfidophilum, into the broad-host-range plasmid vector, pRK415. The biosensor plasmid, pSENSE-As, was introduced into a crtA-deleted mutant strain of R. sulfidophilum (CDM2), which is yellow in culture due to its content of spheroiden (SE) and demethylspheroidene (DMSE). CDM2 containing pSENSE-As changed from yellow to red by the addition of arsenite, which caused enzymatic transformation of SE and DMSE to spheroidenone (SO) and demethylspheroidenone (DMSO). Reverse transcriptase PCR analysis showed that the color change depended on transcription of the crtA gene in pSENSE-As. The color change could be clearly recognized with the naked eye at 5 microg/l arsenite. The biosensor strain did not respond to other metals except for bismuth and antimony, which caused significant accumulation of SO and DMSO in the cells at 60 and 600 microg/l, respectively. This biosensor indicates the presence of arsenite with a bacterial color change without the need to add a special reagent or substrate for color development, enabling this pollutant to be monitored in samples by the naked eye in sunlight, even where electricity is not available.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Masato
authors.initials: M
authors.lastname: Wakabayashi
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yamashiro
authors.forename: Isamu
authors.initials: I
authors.lastname: Maeda
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Isoda
authors.forename: Masuo
authors.initials: M
authors.lastname: Kondoh
authors.forename: Masaya
authors.initials: M
authors.lastname: Kawase
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Miyasaka
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Yagi
mesh_terms: D000965:Antimony / Q000737:chemistry; D053501:Arsenite Transporting ATPases / Q000737:chemistry; D018053:Arsenites / Q000737:chemistry*; D015374:Biosensing Techniques; D001709:Biotechnology / Q000379:methods*; D001729:Bismuth / Q000737:chemistry; D002338:Carotenoids / Q000737:chemistry; D017931:DNA Primers / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D041903:Rhodovulum / Q000378:metabolism*; D013997:Time Factors
chemical_list: D018053:Arsenites; D017931:DNA Primers; D002338:Carotenoids; D000965:Antimony; D053501:Arsenite Transporting ATPases; C015001:arsenite; D001729:Bismuth