title: Bioenergetic investigation of the effects of La(III) and Ca(II) on the metabolic activity of Tetrahymena thermophila BF5.
abstract: The heat flux of Tetrahymena thermophila BF5 during growth and the effects of La(3+) and Ca(2+) on them were investigated with microcalorimetry; simultaneously, morphological changes of T. thermophila were obtained by light microscope. La(3+) in low concentration (0-5.0 x 10(-4) mol/l) remarkably stimulated T. thermophila metabolism, but high dose of La(3+) (5.8-8.6 x 10(-4) mol/l) restrained it in a linear manner with IC(50) being 7.2 x 10(-4) mol/l. In contrast, low concentration of Ca(2+) did not manifest obvious stimulation on T. thermophila metabolism; moreover, the IC(50) of Ca(2+) was much higher than that of La(3+). Low concentration of La(3+) did not lead to changes in appearance of T. thermophila, but low dose of Ca(2+) clearly promoted the cell proliferation. In addition, the morphological changes of T. thermophila evoked by high concentrations of La(3+) and Ca(2+) were consistent with relevant microcalorimetric results. It is concluded that La and Ca influence T. thermophila via different pathways, and La represents toxic action rather than Ca analogy.
authors.affiliation: Department of Chemistry, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Dai
authors.forename: Chuan-Ling
authors.initials: CL
authors.lastname: Li
authors.forename: Ye-Zhong
authors.initials: YZ
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Xiao
authors.forename: Ke-Lin
authors.initials: KL
authors.lastname: Lei
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002151:Calorimetry; D004305:Dose-Response Relationship, Drug; D007811:Lanthanum / Q000494:pharmacology*; D016808:Tetrahymena thermophila / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*
chemical_list: D007811:Lanthanum; D002118:Calcium