title: Morphological and physiological changes exhibited by a Cd-resistant Dictyosphaerium chlorelloides strain and its cadmium removal capacity.
abstract: Changes induced on freshwater microalga Dictyosphaerium chlorelloides (Dc(wt)) acclimated in the laboratory until their survival in culture media enriched with cadmium 100 µM have been studied. Cadmium removal by living cells of this Cd-resistant (Dc(CdR100)) strain was tested in cultures exposed to 100 µM Cd during 30 days. Cell dimensions were measured under light microscopy, and cell growth was studied. Photosynthetic yield (ΦPSII) was analyzed and the photosynthetic oxygen development and respiration response was obtained. Results show that Dc(CdR100) strain exhibited significant cell morphology changes in comparison to Dc(wt) cells, which affected both surface area and cell biovolume. Malthusian fitness analysis showed that Dc(CdR100) strain living in Cd-enriched culture had developed a lower capacity of nearly 50% growth, and its photosynthetic oxygen development and respiration response were significantly reduced in both light and dark photosynthetic phases. Dc(CdR100) strain showed a very high capacity to remove cadmium from the aquatic environment (over 90%), although most of the removed heavy metal (≈70%) is adhered to the cell wall. These specific characteristics of Dc(CdR100) cells suggest the possibility of using this strain in conjunction with Dc(wt) strain as bioelements into a dual-head biosensor, and in bioremediation processes on freshwater polluted with Cd.
authors.affiliation: a School of Chemistry-Pharmacobiology, Michoacana de San Nicolás de Hidalgo University , Morelia , Mexico.
authors.forename: M C
authors.initials: MC
authors.lastname: Bartolomé
authors.affiliation: a School of Chemistry-Pharmacobiology, Michoacana de San Nicolás de Hidalgo University , Morelia , Mexico.
authors.forename: A A
authors.initials: AA
authors.lastname: Cortés
authors.affiliation: b Department of Toxicology and Pharmacology , Faculty of Veterinary Medicine, Universidad Complutense de Madrid , Madrid , Spain.
authors.forename: A
authors.initials: A
authors.lastname: Sánchez-Fortún
authors.affiliation: c Faculty of Civil Engineering, Michoacana de San Nicolás de Hidalgo University , Morelia , Mexico.
authors.forename: M G
authors.initials: MG
authors.lastname: Garnica-Romo
authors.affiliation: d Spanish National Research Council (CSIC), Institute of Natural Resources , Madrid , Spain.
authors.forename: S
authors.initials: S
authors.lastname: Sánchez-Carrillo
authors.affiliation: b Department of Toxicology and Pharmacology , Faculty of Veterinary Medicine, Universidad Complutense de Madrid , Madrid , Spain.
authors.forename: Sebastián
authors.initials: S
authors.lastname: Sánchez-Fortún
mesh_terms: D002104:Cadmium / Q000633:toxicity*; D000460:Chlorophyta / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D058086:Microalgae / Q000187:drug effects* / Q000502:physiology; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium
keywords: Cd-resistant microalgae; Dictyosphaerium chlorelloides; cadmium removal; morphological changes; photosynthesis activity