title: Evaluation of bacterial aerotaxis for its potential use in detecting the toxicity of chemicals to microorganisms.
abstract: Bacterial aerotaxis (the movement of a cell toward oxygen) was evaluated for its potential use in detecting the toxicity of chemicals to microorganisms. The level of toxicity was determined by the concentration of test chemicals resulting in a 50% inhibition of aerotaxis of Pseudomonas aeruginosa PAO1 after 40 min of exposure. The aerotactic responses of P. aeruginosa were measured by using chemotaxis well chambers. Each clear acrylic chamber had a lower and upper well separated by a polycarbonate filter with a uniform pore size of 8.0 microm. To automatically detect bacterial cells that crossed the filter in response to a gradient of oxygen, P. aeruginosa PAO1 was marked with green fluorescent protein (GFP), and the GFP fluorescence intensity in the upper well was continuously monitored by using a fluorescence spectrometer. By using this technique, volatile chlorinated aliphatic compounds, including trichloroethylene (TCE), trichloroethane, and tetrachloroethylene, were found to be inhibitory to bacterial aerotaxis, suggesting their possible toxicity to microorganisms. We also examined more than 20 potential toxicants for their ability to inhibit the aerotaxis of P. aeruginosa. Based on these experimental results, we concluded that bacterial aerotaxis has potential for use as a fast and reliable indicator in assessing the toxicity of chemicals to microorganisms.
authors.affiliation: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan.
authors.forename: Maiko
authors.initials: M
authors.lastname: Shitashiro
authors.forename: Junichi
authors.initials: J
authors.lastname: Kato
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Fukumura
authors.forename: Akio
authors.initials: A
authors.lastname: Kuroda
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Ikeda
authors.forename: Noboru
authors.initials: N
authors.lastname: Takiguchi
authors.forename: Hisao
authors.initials: H
authors.lastname: Ohtake
mesh_terms: D015374:Biosensing Techniques; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects* / Q000502:physiology; D005240:Feasibility Studies; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D007928:Lethal Dose 50; D010100:Oxygen / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000166:cytology / Q000187:drug effects* / Q000302:isolation & purification* / Q000502:physiology; D013050:Spectrometry, Fluorescence / Q000379:methods; D018675:Toxicity Tests / Q000295:instrumentation / Q000379:methods*
chemical_list: D006843:Hydrocarbons, Chlorinated; D010100:Oxygen