title: [The mechanisms of 232Th and of Ce (III) toxic action on Chlorella vulgaris Beijer. Estimation of 232Th radiation impact contribution into toxic effect induced].
abstract: 232Th and Ce (III) toxic effects and its modifications with caffeine and D,L-buthionine-(S,R)-sulphoximine on Chlorella vulgaris Beijer were studied using an optical density measure after 24 hours growth. Concentrations of 232Th or of Ce--toxic effect relationship were shown to be nonlinear. In the first (nontoxic) concentration range (for Ce 0.036-1.642 micromol/L and for 232Th 0.001-1.551 micromol/L) algae biomass production registered by optical density do not significantly differ from the control one. In the second (toxic) concentration range dose-effect relationship for 232Th is characterized with quadratic dependence and in the case of Ce--with exponential dependence. 232Th radiation component contribution into effect observed is appeared as induction of DNA damages additional to spontaneous at the radionuclide concentration (equal to 0.345 micromol/L) that is three times lower than in case of the non-radioactive chemical analog Ce (1.071 micromol/L).
authors.forename: T I
authors.initials: TI
authors.lastname: Evseeva
authors.forename: T A
authors.initials: TA
authors.lastname: Maĭstrenko
authors.forename: S A
authors.initials: SA
authors.lastname: Geras'kin
authors.forename: E S
authors.initials: ES
authors.lastname: Belykh
mesh_terms: D002563:Cerium / Q000633:toxicity*; D048408:Chlorella vulgaris / Q000187:drug effects* / Q000235:genetics / Q000528:radiation effects*; D004249:DNA Damage; D048028:DNA, Algal / Q000235:genetics / Q000528:radiation effects; D013910:Thorium / Q000633:toxicity*
chemical_list: D048028:DNA, Algal; D002563:Cerium; D013910:Thorium; C026690:cerous chloride