title: Voltammetric detection and profiling of isoprenoid quinones hydrophobically transferred from bacterial cells.
abstract: We have developed a novel bacterial detection technique by desiccating a bacterial suspension deposited on an electrode. It was also found that the use of an indium-tin-oxide (ITO) electrode dramatically improved the resolution of the voltammogram, allowing us to observe two pairs of redox peaks, each assigned to the adsorption of isoprenoid ubiquinone (UQn) and menaquinone (MKn), which were present in the bacterial cell envelopes, giving midpeak potentials of -0.015 and -0.25 V versus Ag|AgCl|saturated KCl| at pH 7.0, respectively. Most of the microorganisms classified in both the Gram-negative and -positive bacteria gave well-defined redox peaks, demonstrating that this procedure made the detection of the quinones possible without solvent extraction. It has been demonstrated that the present technique can be used not only for the detection of bacteria, but also for profiling of the isoprenoid quinones, which play important roles in electron and proton transfer in microorganisms. In this respect, the present technique provides a much more straightforward way than the solvent extraction in that one sample can be prepared in 1 min by heat evaporation of a suspension containing the targeted bacteria, which has been applied on the ITO electrode.
authors.affiliation: †Department of Applied Chemistry, Osaka Prefecture University, 1-2 Gakuen, Naka, Sakai, Osaka 599-8570, Japan.
authors.forename: Dung Quynh
authors.initials: DQ
authors.lastname: Le
authors.affiliation: †Department of Applied Chemistry, Osaka Prefecture University, 1-2 Gakuen, Naka, Sakai, Osaka 599-8570, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Morishita
authors.affiliation: †Department of Applied Chemistry, Osaka Prefecture University, 1-2 Gakuen, Naka, Sakai, Osaka 599-8570, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Tokonami
authors.affiliation: †Department of Applied Chemistry, Osaka Prefecture University, 1-2 Gakuen, Naka, Sakai, Osaka 599-8570, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Nishino
authors.affiliation: †Department of Applied Chemistry, Osaka Prefecture University, 1-2 Gakuen, Naka, Sakai, Osaka 599-8570, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shiigi
authors.affiliation: ‡Department of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku-Ohrai-Kita, Izumisano, Osaka 598-8531, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Miyake
authors.affiliation: †Department of Applied Chemistry, Osaka Prefecture University, 1-2 Gakuen, Naka, Sakai, Osaka 599-8570, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nagaoka
mesh_terms: D055664:Electrochemical Techniques; D004566:Electrodes; D006090:Gram-Negative Bacteria / Q000737:chemistry / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000737:chemistry* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D010084:Oxidation-Reduction; D011809:Quinones / Q000032:analysis*; D017971:Tin Compounds / Q000737:chemistry; D024482:Vitamin K 2 / Q000032:analysis
chemical_list: D011809:Quinones; D017971:Tin Compounds; D024482:Vitamin K 2; C109984:indium tin oxide