title: Growth-dependent catalase localization in Exiguobacterium oxidotolerans T-2-2T reflected by catalase activity of cells.
abstract: A psychrotolerant and H2O2-resistant bacterium, Exiguobacterium oxidotolerans T-2-2(T), exhibits extraordinary H2O2 resistance and produces catalase not only intracellularly but also extracellularly. The intracellular and extracellular catalases exhibited the same enzymatic characteristics, that is, they exhibited the temperature-dependent activity characteristic of a cold-adapted enzyme, their heat stabilities were similar to those of mesophilic enzymes and very high catalytic intensity. In addition, catalase gene analysis indicated that the bacterium possessed the sole clade 1 catalase gene corresponding to intracellular catalase. Hence, intracellular catalase is secreted into the extracellular space. In addition to intracellular and extracellular catalases, the inner circumference of the cells showed the localization of catalase in the mid-stationary growth phase, which was observed by immunoelectron microscopy using an antibody against the intracellular catalase of the strain. The cells demonstrated higher catalase activity in the mid-stationary growth phase than in the exponential growth phase. The catalase localized in the inner circumference can be dissociated by treatment with Tween 60. Thus, the localized catalase is not tightly bound to the inner circumference of the cells and may play a role in the oxidative defense of the cells under low metabolic state.
authors.affiliation: Laboratory of Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Japan ; Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Toyohira-ku, Sapporo, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Hanaoka
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Takebe
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Nodasaka
authors.forename: Isao
authors.initials: I
authors.lastname: Hara
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Matsuyama
authors.forename: Isao
authors.initials: I
authors.lastname: Yumoto
mesh_terms: D056449:Bacillales / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055162:Biocatalysis / Q000187:drug effects; D002374:Catalase / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D004795:Enzyme Stability / Q000187:drug effects; D005110:Extracellular Space / Q000201:enzymology*; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D042541:Intracellular Space / Q000201:enzymology*; D007700:Kinetics; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016877:Oxidants / Q000378:metabolism / Q000494:pharmacology; D011136:Polysorbates / Q000737:chemistry / Q000494:pharmacology; D020539:Sequence Analysis, Protein; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D016877:Oxidants; D011136:Polysorbates; D006861:Hydrogen Peroxide; D002374:Catalase