Showing papers by "Utsunomiya University published in 2008"
TL;DR: It is proposed that strigolactones act as a new hormone class—or their biosynthetic precursors—in regulating above-ground plant architecture, and also have a function in underground communication with other neighbouring organisms.
Abstract: Shoot branching is a major determinant of plant architecture and is highly regulated by endogenous and environmental cues. Two classes of hormones, auxin and cytokinin, have long been known to have an important involvement in controlling shoot branching. Previous studies using a series of mutants with enhanced shoot branching suggested the existence of a third class of hormone(s) that is derived from carotenoids, but its chemical identity has been unknown. Here we show that levels of strigolactones, a group of terpenoid lactones, are significantly reduced in some of the branching mutants. Furthermore, application of strigolactones inhibits shoot branching in these mutants. Strigolactones were previously found in root exudates acting as communication chemicals with parasitic weeds and symbiotic arbuscular mycorrhizal fungi. Thus, we propose that strigolactones act as a new hormone class-or their biosynthetic precursors-in regulating above-ground plant architecture, and also have a function in underground communication with other neighbouring organisms.
1,742 citations
TL;DR: Two waves of gene expression are identified in the quail MBH associated with the initiation of photoinduced secretion of luteinizing hormone and increased TSH in the pars tuberalis seems to trigger long-day photoinduced seasonal breeding.
Abstract: Molecular mechanisms regulating animal seasonal breeding in response to changing photoperiod are not well understood. Rapid induction of gene expression of thyroid-hormone-activating enzyme (type 2 deiodinase, DIO2) in the mediobasal hypothalamus (MBH) of the Japanese quail (Coturnix japonica) is the earliest event yet recorded in the photoperiodic signal transduction pathway. Here we show cascades of gene expression in the quail MBH associated with the initiation of photoinduced secretion of luteinizing hormone. We identified two waves of gene expression. The first was initiated about 14 h after dawn of the first long day and included increased thyrotrophin (TSH) beta-subunit expression in the pars tuberalis; the second occurred approximately 4 h later and included increased expression of DIO2. Intracerebroventricular (ICV) administration of TSH to short-day quail stimulated gonadal growth and expression of DIO2 which was shown to be mediated through a TSH receptor-cyclic AMP (cAMP) signalling pathway. Increased TSH in the pars tuberalis therefore seems to trigger long-day photoinduced seasonal breeding.
467 citations
TL;DR: The regulation of strigolactone production and/or exudation seems to be closely related to the nutrient acquisition strategy of the plants.
Abstract: Summary
• Both root parasitic plants and arbuscular mycorrhizal (AM) fungi take advantage of strigolactones, released from plant roots as signal molecules in the initial communication with host plants, in order to commence parasitism and mutualism, respectively.
• In this study, strigolactones in root exudates from 12 Fabaceae plants, including hydroponically grown white lupin (Lupinus albus), a nonhost of AM fungi, were characterized by comparing retention times of germination stimulants on reverse-phase high-performance liquid chromatography (HPLC) with those of standards and by using tandem mass spectrometry (LC/MS/MS).
• All the plant species examined were found to exude known strigolactones, such as orobanchol, orobanchyl acetate, and 5-deoxystrigol, suggesting that these strigolactones are widely distributed in the Fabaceae. It should be noted that even the nonmycotrophic L. albus exuded orobanchol, orobanchyl acetate, 5-deoxystrigol, and novel germination stimulants.
• By contrast to the mycotrophic Fabaceae plant Trifolium pratense, in which phosphorus deficiency promoted strigolactone exudation, neither phosphorus nor nitrogen deficiency increased exudation of these strigolactones in L. albus. Therefore, the regulation of strigolactone production and/or exudation seems to be closely related to the nutrient acquisition strategy of the plants.
270 citations
TL;DR: Strain VIR07 showed the response of violacein production when AHLs diffused from a variety of AHL-producing bacteria on agar plates, and thus might be a useful biosensor for recognizing exogenous AHLs.
Abstract: In tests, Chromobacterium violaceum ATCC 12472 produced several N-acyl-L-homoserine lactones (AHLs). Of these, N-(3-hydroxydecanoyl)-L-homoserine lactone was dominant, and controlled violacein production by quorum sensing. Strain VIR07, an AHL-deficient mutant, did not produce violacein. Violacein production in VIR07 was induced by adding long-chain AHLs (C10-C16), but was inhibited by adding short-chain AHLs (C4-C8). Strain VIR07 showed the response of violacein production when AHLs diffused from a variety of AHL-producing bacteria on agar plates, and thus might be a useful biosensor for recognizing exogenous AHLs.
201 citations
TL;DR: The results obtained, indicate that the BPA removal at BDD depends on the applied current density (Iappl), initial concentration of BPA, pH of electrolyte and supporting medium, and accordingly the mineralization current efficiency was calculated from the TOC removal measurements.
195 citations
Hirosaki University1, Chinese Academy of Sciences2, Yokohama National University3, Hebei Normal University4, Tibet University5, Shandong University6, Southwest Jiaotong University7, Yunnan University8, Kanagawa University9, Utsunomiya University10, University of Tokyo11, Konan University12, Waseda University13, Shinshu University14, Tsinghua University15, Saitama University16, National Institute of Informatics17, College of Industrial Technology18, Max Planck Society19, Shonan Institute of Technology20
TL;DR: In this paper, the authors presented an updated all-particle energy spectrum of primary cosmic rays in a wide range from 10 14 to 10 17 eVusing 5:5 ; 10 7 events collected from 2000 November through 2004 October by the Tibet-III air-shower array located 4300 m in altitude.
Abstract: We present an updated all-particle energy spectrum of primary cosmic rays in a wide range from 10 14 to 10 17 eVusing 5:5 ; 10 7 events collected from 2000 November through 2004 October by the Tibet-III air-shower array located 4300 m abovesealevel(anatmosphericdepthof 606gcm � 2 ).Thesizespectrumexhibitsasharpkneeatacorrespondingprimary energy around 4 PeV. This work uses increased statistics and new simulation calculations for the analysis. We discuss our extensive Monte Carlo calculations and the model dependencies involved in thefinal result, assuming interaction models QGSJET01c and SIBYLL2.1, and heavy dominant (HD) and proton dominant (PD) primary composition models. Pure protonandpureironprimarymodelsarealsoexaminedasextremecases.A detector simulationwasalsoperformedtoimproveouraccuracyindeterminingthesizeof theairshowersandtheenergyof theprimaryparticle.Weconfirmedthatthe all-particle energy spectra obtained under various plausible model parameters are not significantly different from each other, which was the expected result given the characteristics of the experiment at high altitude, where the air showers of the primary energy around the knee reach near-maximum development, with their features dominated by electromagnetic components,leadingtoaweakdependenceontheinteractionmodel or theprimarymass.Thisisthehighest statistical and the best systematics-controlled measurement covering the widest energy range around the knee energy region.
194 citations
TL;DR: The phylogenetic tree of cuticular protein genes among B. mori, Drosophila melanogaster, and Apis mellifera revealed that duplicate cuticularprotein clusters have evolved independently among insects.
167 citations
TL;DR: The germination stimulants produced by Arabidopsis thaliana, a host of root parasitic plants Orobanche spp.
Abstract: The germination stimulants produced by Arabidopsis thaliana, a host of root parasitic plants Orobanche spp. but not of arbuscular mycorrhizal (AM) fungi were examined. Root exudates from the hydroponically grown A. thaliana plants were subjected to reverse phase high performance liquid chromatography (HPLC) and retention times of germination stimulants inducing O. aegyptiaca seed germination were compared with those of strigolactone standards. In addition, the root exudates were analyzed by using HPLC linked with tandem mass spectrometry (LC/MS/MS). A. thaliana was found to exude at least three different germination stimulants of which one was identified as orobanchol. This is the first report of strigolactone production by a non-mycotrophic plant. These results together with recent knowledge imply that strigolactones have other unrevealed functions in plant growth and development.
95 citations
TL;DR: The present paper used existing knowledge on the structure of strigolactones and combined it with recently obtained insight in the biosynthetic origin of these signalling compounds to postulate structures for Striga and Orobanche species that have been isolated but for which so far the structure has not been elucidated, but also to propose structures of striglactones that may be discovered in the future.
92 citations
TL;DR: HPLC analysis revealed that Aac worked as AHL-acylase, which hydrolyzed the amide bond of AHL, and expression of Aac in fish pathogen Vibrio anguillarum markedly reduced AHL production and biofilm formation, indicating that AAC might be effective in quenching quorum sensing of fish pathogens.
Abstract: N-Acylhomoserine lactones (AHLs) are used as quorum-sensing signal molecules by many gram-negative bacteria. We have reported that Shewanella sp. strain MIB015 degrades AHLs. In the present study, we cloned the aac gene from MIB015 by PCR with specific primers based on the aac gene in Shewanella oneidensis strain MR-1, which showed high homology with the known AHL-acylases. Escherichia coli expressing Aac showed high degrading activity of AHLs with long acyl chains. HPLC analysis revealed that Aac worked as AHL-acylase, which hydrolyzed the amide bond of AHL. In addition, expression of Aac in fish pathogen Vibrio anguillarum markedly reduced AHL production and biofilm formation. In conclusion, this study indicates that Aac might be effective in quenching quorum sensing of fish pathogens.
92 citations
TL;DR: Alectrol, a germination stimulant for root parasitic plants, was purified from root exudates of red clover and identified as a strigolactone, (+)-orobanchyl acetate by 1D and 2D NMR spectroscopy and ESI and EI-MS spectrometry.
TL;DR: In this paper, a simple and fast coating method that is based on microwave (MW) irradiation and which uses polydiethoxysiloxane (PDES) has been developed for TiO 2 nanoparticles with the aim of reducing their photocatalytic activity.
TL;DR: A multihole thin-foil target is proposed in order to increase the energy-conversion efficiency from laser to protons and the multiholes transpiercing the foil target helps to enhance the laser-proton energy-Conversion efficiency significantly.
Abstract: Improvement of energy-conversion efficiency from laser to proton beam is demonstrated by particle simulations in a laser-foil interaction. When an intense short-pulse laser illuminates the thin-foil target, the foil electrons are accelerated around the target by the ponderomotive force. The hot electrons generate a strong electric field, which accelerates the foil protons, and the proton beam is generated. In this paper a multihole thin-foil target is proposed in order to increase the energy-conversion efficiency from laser to protons. The multiholes transpiercing the foil target help to enhance the laser-proton energy-conversion efficiency significantly. Particle-in-cell 2.5-dimensional ($x$, $y$, ${v}_{x}$, ${v}_{y}$, ${v}_{z}$) simulations present that the total laser-proton energy-conversion efficiency becomes 9.3% for the multihole target, though the energy-conversion efficiency is 1.5% for a plain thin-foil target. The maximum proton energy is $10.0\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ for the multihole target and is $3.14\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ for the plain target. The transpiercing multihole target serves as a new method to increase the energy-conversion efficiency from laser to ions.
TL;DR: In this paper, the X-ray photoelectron spectroscopy (XPS) spectra of Yb 4f, 5p, 4d and 4p have been measured.
TL;DR: In this paper, the authors investigated the recovery of species composition, diversity, and aboveground biomass in secondary forests that were abandoned after swidden cultivation for more than 20 years in a Karen village in Doi Inthanon National Park.
TL;DR: In this paper, a new and rapid method for silica coating of ZnO nanoparticles by the simple microwave irradiation technique is reported, which is characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopic (FT-IR), high-resolution transmission electron microscopy (HR-TEM), CHN elemental analysis and zeta potential measurements.
TL;DR: It was concluded that Bidens frondosa, Bidens pilosa and Amaranthus viridis, which not only have a high Cd accumulation ability but also a large biomass, are useful species for Cd phytoremediation.
Abstract: The present study was conducted to find useful weed species for cadmium (Cd) phytoremediation. Ninety-three weed species and eight crop species were grown for 2 months in pots containing sandy loam soil with 3 mg Cd kg−1 dry weight (DW). The Cd concentrations in the shoots and roots of all species were determined by inductively coupled plasma optical emission spectroscopy and atomic absorption spectrometry. Shoot Cd concentrations (mg kg−1 DW) of Cichorium intybus (77.0) and Matricaria chamomilla (64.4) were higher than that of Polygonum thunbergii (56.2), which is a recognized hyperaccumulator. Root Cd concentrations (mg kg−1 DW) were relatively high (≥ 100) in 11 species, for example, Oenothera biennis (171.9), Calystegia sepium var. americana (122.6) and Cassia obtusifolia (122.2). Shoot–root ratios (ratio of shoot and root Cd concentrations) were higher in Compositae species, for example, Cichorium intybus (3.56) and Bidens frondosa (3.30), than in Gramineae species, for example, Oenothera bi...
TL;DR: It is demonstrated that maternal-feeding signals can be more influential for the fetal SCN and particular organ oscillators than hormonal signals controlled by the maternal SCN, suggesting the importance of a regular maternal feeding schedule for appropriate fetal molecular clockwork during pregnancy.
Abstract: BackgroundIt is widely accepted that circadian physiological rhythms of the fetus are affected by oscillators in the maternal brain that are coupled to the environmental light-dark (LD) cycle.Methodology/Principal FindingsTo study the link between fetal and maternal biological clocks, we investigated the effects of cycles of maternal food availability on the rhythms of Per1 gene expression in the fetal suprachiasmatic nucleus (SCN) and liver using a transgenic rat model whose tissues express luciferase in vitro. Although the maternal SCN remained phase-locked to the LD cycle, maternal restricted feeding phase-advanced the fetal SCN and liver by 5 and 7 hours respectively within the 22-day pregnancy.Conclusions/SignificanceOur results demonstrate that maternal feeding entrains the fetal SCN and liver independently of both the maternal SCN and the LD cycle. This indicates that maternal-feeding signals can be more influential for the fetal SCN and particular organ oscillators than hormonal signals controlled by the maternal SCN, suggesting the importance of a regular maternal feeding schedule for appropriate fetal molecular clockwork during pregnancy.
TL;DR: In this paper, a strigolactone sorgomol, a germination stimulant for root parasitic plants Striga and Orobanche, was isolated and structure was elucidated.
TL;DR: It will be shown, how macrocyclic compounds as well as rotaxanes or helicates can be formed by use of butenylidene bridged aromatic compounds obtained after the rearrangement reaction.
Abstract: The tandem Claisen rearrangement is a simple but highly efficient reaction to synthesize useful building blocks for supramolecular chemistry. It provides in one step two new C–C bonds in very high yield. The scope and limits of this reaction will be discussed in this review and it will be shown, how macrocyclic compounds as well as rotaxanes or helicates can be formed by use of butenylidene bridged aromatic compounds obtained after the rearrangement reaction. Special aspects will cover the search for new receptors and sensors or for energy transfer properties. The contents of this tutorial review are within the field of preparative organic synthesis but in addition cover aspects of inorganic and supramolecular chemistry.
TL;DR: In this article, the authors studied laser interactions with mass-limited targets via numerical simulations using relativistic electromagnetic two-dimensional particle-in cell code including all three-velocity components.
Abstract: Laser interactions with mass-limited targets are studied here via numerical simulations using our relativistic electromagnetic two-dimensional particle-in cell code including all three-velocity components. Analytical estimates are derived to clarify the simulation results. Mass-limited targets preclude the undesirable spread of the absorbed laser energy out of the interaction zone. Mass-limited targets, such as droplets, are shown here to enhance the achievable fast ion energy significantly due to an increase in the hot electron concentration. For given target dimensions, the existence is demonstrated for an optimum laser beam diameter when ion acceleration is efficient and geometrical energy losses are still acceptable. Ion energy also depends on the target geometrical form and rounded targets are found to enhance the energy of accelerated ions. The acceleration process is accompanied by generation of the dipole radiation in addition to the ordinary scattering of the electromagnetic wave.
Çukurova University1, Middle East Technical University2, University of Bari3, Humboldt University of Berlin4, University of Cagliari5, University of Ferrara6, Toho University7, CERN8, Technion – Israel Institute of Technology9, Kindai University10, Boğaziçi University11, Gyeongsang National University12, Aichi University of Education13, Kobe University14, Université catholique de Louvain15, University of Münster16, Nagoya University17, Osaka City University18, Sapienza University of Rome19, University of Salerno20, Utsunomiya University21
TL;DR: In this article, the final oscillation analysis of the complete set of data collected by CHORUS in the years 1994-1997 is presented, where reconstruction algorithms of data extracted by electronic detectors were improved and the data recorded in the emulsion target were analysed by new automated scanning systems, allowing the use of a new method for event reconstruction in emulsion.
TL;DR: Using a more precise estimation method by selecting the optimum body posture, electrode arrangement, and frequency, an accurate assessment of VFA is obtained using the bioelectrical impedance method.
Abstract: Excessive visceral fat area (VFA) is a major risk factor in such conditions as cardiovascular disease. In assessing VFA, computed tomography (CT) is adopted as the gold standard; however, this method is cost intensive and involves radiation exposure. In contrast, the bioelectrical impedance (BI) method for estimating body composition is simple and noninvasive and thus its potential application in VFA assessment is being studied. To overcome the difference in obtained impedance due to measurement conditions, we developed a more precise estimation method by selecting the optimum body posture, electrode arrangement, and frequency. The subjects were 73 healthy volunteers, 37 men and 36 women, who underwent CT scans to assess VFA and who were measured for anthropometry parameters, subcutaneous fat layer thickness, abdominal tissue area, and impedance. Impedance was measured by the tetrapolar impedance method using multi-frequency BI. Multiple regression analysis was conducted to estimate VFA. The results revealed a strong correlation between VFA observed by CT and VFA estimated by impedance (r = 0.920). The regression equation accurately classified VFA > or = 100 cm(2) in 13 out of 14 men and 1 of 1 woman. Moreover, it classified VFA > or = 100 cm(2) or < 100 cm(2) in 3 out of 4 men and 1 of 1 woman misclassified by waist circumference (W) which was adopted as a simple index to evaluate VFA. Therefore, using this simple and convenient method for estimating VFA, we obtained an accurate assessment of VFA using the BI method.
TL;DR: In this paper, the authors obtained basic knowledge for the prediction of the mechanical properties of Japanese larch lumber (Larix kaempferi) on the basis of tree properties, such as the stress-wave velocity (SWV) and Pilodyn penetration value (Py).
Abstract: The objective of this study was to obtain basic knowledge for the prediction of the mechanical properties
of Japanese larch lumber (Larix kaempferi) on the basis of tree properties,
such as the stress-wave velocity (SWV) and Pilodyn penetration value (Py). The values of the correlation
coefficient between the SWV of a standing tree and the dynamic Young’s modulus (DMOE) of logs, which
were obtained at various heights, gradually decreased with an increase in the log sampling height, indicating
that the SWV of a tree is affected by wood properties at the measuring position. A significant
correlation between the SWV of trees and the average modulus of elasticity (MOE) of lumber was found (r
=0.834). A significant negative correlation between the Py of a tree and the average modulus
of rupture (MOR) of lumber was also found (r=-0.859). A high coefficient of determination for
an obtained regression curve was found when both the SWV and Py of a tree were used for evaluating
the average MOE or MOR of lumber. These results indicate that the average MOE and MOR of lumber can
be predicted by using the SWV and Py of the Japanese larch tree.
TL;DR: A sparse exposure technique combining parallel exposure and scanning exposure is demonstrated to improve the fabrication throughput and to achieve simultaneous fabrication of linear structures with different widths.
Abstract: Holographic two-photon polymerization is based on a high-speed, low-loss parallel laser irradiation technique inside photosensitive materials using a computer-generated hologram displayed on a liquid crystal spatial light modulator. We demonstrated a sparse exposure technique combining parallel exposure and scanning exposure to improve the fabrication throughput and to achieve simultaneous fabrication of linear structures with different widths. We also demonstrated fabrication of space-variant structures by changing a CGH, as well as parallel fabrication of voxel structures with single femtosecond laser pulse irradiation.
TL;DR: There is a cooperative interaction among embryos during culture and that this interaction may be mediated by reduction of toxic factors in the medium at low embryo density, reduced oxygen concentration or the exclusion of inorganic phosphate enhanced blastocyst development.
Abstract: Various factors such as embryo density and substances in the medium can influence embryo development in vitro. These factors and the embryos probably interact with each other, however the interactions are not fully understood. To investigate the interactions, we examined the effects of the number of embryos, drop size, oxygen concentration and glucose and inorganic phosphate in the medium during protein-free culture of bovine IVM/IVF embryos. In Experiment 1, different numbers of embryos were cultured in a 50 microl drop of medium. The frequencies of blastocyst development in the groups with 25, 50 and 100 embryos per drop were higher than in the other groups. One, five and 25 embryos were cultured in different drop sizes (Experiment 2), a 50 microl drop of medium at different O2 concentrations (Experiment 3) and a 50 microl drop of medium excluding glucose and/or inorganic phosphate (Experiment 4). In Experiment 2, the size of the medium drops did not improve blastocyst development. In Experiment 3, the highest frequency of blastocyst development for one, five and 25 embryos per drop was obtained at 1, 2.5 and 5% O2, respectively. In Experiment 4, blastocyst development for one and five embryos per drop were improved in the medium excluded inorganic phosphate. These results indicate that there is a cooperative interaction among embryos during culture and that this interaction may be mediated by reduction of toxic factors in the medium. At low embryo density, reduced oxygen concentration or the exclusion of inorganic phosphate enhanced blastocyst development.
TL;DR: The optical spectra of a series of core-modified tetrabenzoporphyrins were analyzed to determine the effects of core modification, ligand folding, and partial benzo substitution at the ligand periphery on the electronic structure by using magnetic circular dichroism and NMR spectroscopy, X-ray crystallography, cyclic and differential pulse voltammetry, and TD-DFT calculations.
Abstract: The optical spectra of a series of core-modified tetrabenzoporphyrins were analyzed to determine the effects of core modification, ligand folding, and partial benzo substitution at the ligand periphery on the electronic structure by using magnetic circular dichroism (MCD) and NMR spectroscopy, X-ray crystallography, cyclic and differential pulse voltammetry, and TD-DFT calculations. Planar 21-carba-, 21-thia-, 21,23-dithia-, and 21-oxa-23-thiatetrabenzo[b,g,l,q]porphyrins reported previously were studied together with the previously unreported 21-oxa- and 21-carba-23-thiatetrabenzo[b,g,l,q]porphyrins. The optical properties of these compounds are compared to those of tetrabenzo[b,g,l,q]-, 5,10,15,20-tetraphenyl-, 5,10,15,20-tetraphenyltetrabenzo[b,g,l,q]-21-thia-, 5,10,15,20-tetraphenyltetrabenzodithia-, 5,10,15,20-tetraphenyldibenzo[g,q]-21,23-dithia-, 5,10,15,20-tetraphenyldibenzo[b,l]-21,23-dithia-, 5,10,15,20-tetraphenyltribenzo[g,q,l]-21-thia-, and 5,10,15,20-tetraphenylbenzo[b]-21-thiaporphyrins. Michl's perimeter model and Gouterman's four-orbital model are used to conceptualize the results and to account for red shifts commonly observed in the spectral bands of nonplanar porphyrinoids.
TL;DR: In this article, a micro fracture behavior of the grain cutting edge that is the most important factor controlling the grinding ability of cBN wheels during the grinding process was presented, and the 3D profile of the worn cutting edge has been evaluated by means of the fractal analysis.
TL;DR: In this article, the performance of a porous ceramic membrane reactor for methane steam reforming using nitrogen and steam as sweep gases was analyzed via numerical simulation, and the results showed that the use of steam as the sweep gas showed the better performance in terms of methane conversion and hydrogen recovery yield.
TL;DR: Colimetric analysis of the bacteria showed that the hue angle had clearly shifted from green-yellow toward red in an arsenic dose-dependent manner at 24 h after arsenite addition, indicating that the color change of the biosensor is stable in water samples containing various concentrations of dissolved oxygen.
Abstract: A novel whole-cell arsenite biosensor was developed using the photosynthetic bacterium Rhodopseudomonas palustris no. 7 and characterized. A sensor plasmid containing the operator-promoter region of the ars operon and arsR gene from Escherichia coli and the crtI gene from R. palustris no. 7 was introduced into a blue-green mutant with crtI deleted, R. palustris no. 711. The biosensor changed color in response to arsenite, and the change was obvious to the naked eye after 24 h without further manipulation. Real-time reverse transcription-PCR showed that the crtI mRNA was induced 3-fold at 3 h and 2.5-fold at 6 h after addition of 50 μg/liter arsenite compared with the no-arsenite control, and consistent with this, the relative levels of lycopene and rhodopin also increased compared with the control. Colorimetric analysis of the bacteria showed that the hue angle had clearly shifted from green-yellow toward red in an arsenic dose-dependent manner at 24 h after arsenite addition. This obvious shift occurred irrespective of the culture conditions before arsenite was added, indicating that the color change of the biosensor is stable in water samples containing various concentrations of dissolved oxygen. Finally, assays using samples prepared in various types of mineral water indicated that this biosensor could be used to screen groundwater samples for the presence of arsenite in a variety of locations, even where electricity is not available.