RT Journal Article
T1 Toxicity, physiological, and ultrastructural effects of Arsenic and Cadmium on the extremophilic microalga Chlamydomonas acidophila
A1 Díaz, Silvia
A1 Francisco Martínez, Patricia de
A1 Olsson, Sanna
A1 Aguilera, Ángeles
A1 González-Toril, Elena
A1 Martín González, Ana María
AB The cytotoxicity of cadmium (Cd), arsenate (As(V)), and arsenite (As(III)) on a strain of Chlamydomonas acidophila, isolated from the Rio Tinto, an acidic environment containing high metal(l)oid concentrations, was analyzed. We used a broad array of methods to produce complementary information: cell viability and reactive oxygen species (ROS) generation measures, ultrastructural observations, transmission electron microscopy energy dispersive x-ray microanalysis (TEM–XEDS), and gene expression. This acidophilic microorganism was affected differently by the tested metal/metalloid: It showed high resistance to arsenic while Cd was the most toxic heavy metal, showing an LC50 = 1.94 µM. Arsenite was almost four-fold more toxic (LC50= 10.91 mM) than arsenate (LC50 = 41.63 mM). Assessment of ROS generation indicated that both arsenic oxidation states generate superoxide anions. Ultrastructural analysis of exposed cells revealed that stigma, chloroplast, nucleus, and mitochondria were the main toxicity targets. Intense vacuolization and accumulation of energy reserves (starch deposits and lipid droplets) were observed after treatments. Electron-dense intracellular nanoparticle-like formation appeared in two cellular locations: inside cytoplasmic vacuoles and entrapped into the capsule, around each cell. The chemical nature (Cd or As) of these intracellular deposits was confirmed by TEM–XEDS. Additionally, they also contained an unexpected high content in phosphorous, which might support an essential role of poly-phosphates in metal resistance.
PB MDPI
SN 1661-7827, ESSN: 1660-4601
YR 2020
FD 2020-03-03
LK https://hdl.handle.net/20.500.14352/6261
UL https://hdl.handle.net/20.500.14352/6261
LA eng
NO Ministerio de Ciencia e Innovación (MICINN)
NO Universidad Complutense de Madrid (UCM)/Banco de Santander
DS Docta Complutense
RD 24 ago 2024