title: Inducible aluminum resistance of Acidiphilium cryptum and aluminum tolerance of other acidophilic bacteria.
abstract: Aluminum ions are highly soluble in acidic environments. Toxicity of aluminum ions for heterotrophic, facultatively and obligately chemolithoautotrophic acidophilic bacteria was examined. Acidiphilium cryptum grew in glucose-mineral medium, pH 3, containing 300 mM aluminum sulfate [Al(2)(SO(4))(3)] after a lag phase of about 120 h with a doubling time of 7.6 h, as compared to 5.2 h of growth without aluminum. Precultivation with 1 mM Al(2)(SO(4))(3) and transfer to a medium with 300 mM Al(2)(SO(4))(3) reduced the lag phase from 120 to 60 h, and immediate growth was observed when A. cryptum was precultivated with 50 mM Al(2)(SO(4))(3), suggesting an aluminum-induced resistance. Aluminum resistance was not induced by Fe(3+) ions and divalent cations. Upon exposure of A. cryptum to 300 mM Al(2)(SO(4))(3), the protein profile changed significantly as determined by SDS-PAGE. When other acidophiles were cultivated with 50-200 mM aluminum sulfate, no lag phase was observed while the growth rates and the cellular yields were significantly reduced. This growth response was observed with Acidobacterium capsulatum, Acidiphilium acidophilum, Acidithiobacillus ferrooxidans, and Acidithiobacillus thiooxidans. Precultivation of these strains with aluminum ions did not alter the growth response caused by aluminum. The content of A. cryptum cultivated with 300 mM Al(2)(SO(4))(3)was 0.44 microg Al/mg cell dry weight, while that of the other strains cultivated with 50 mM Al(2)(SO(4))(3) ranged from 0.30 to 3.47 microg Al/mg cell dry weight.
authors.affiliation: Lehrstuhl für Technische Mikrobiologie, Fachbereich Chemietechnik, Universität Dortmund, Emil-Figge-Strasse 66, 44221 Dortmund, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Fischer
authors.forename: Armin
authors.initials: A
authors.lastname: Quentmeier
authors.forename: Sven
authors.initials: S
authors.lastname: Gansel
authors.forename: Vera
authors.initials: V
authors.lastname: Sabados
authors.forename: Cornelius G
authors.initials: CG
authors.lastname: Friedrich
mesh_terms: D016947:Acetobacteraceae / Q000187:drug effects* / Q000378:metabolism; D000535:Aluminum / Q000494:pharmacology*; D001673:Biodegradation, Environmental; D002455:Cell Division / Q000187:drug effects; D024881:Drug Resistance, Bacterial; D012988:Soil Microbiology
chemical_list: D000535:Aluminum