title: Effects of chlorpyrifos on the growth and ultrastructure of green algae, Ankistrodesmus gracilis.
abstract: The effect of the organophosphorus insecticide chlorpyrifos on the growth, biovolume, and ultrastructure of the green microalga Ankistrodesmus gracilis was evaluated. Concentrations of 9.37, 18.75, 37.5, 75 and 150mgL(-1) of chlorpyrifos were assayed along with a control culture. At the end of the bioassay the ultrastructure of algal cells from control culture and from cultures exposed to 37.5 and 150mgL(-1) was observed under transmission (TEM) and scanning electron microscopy (SEM). After 24 and 48h, treatments with 75 and 150mgL(-1) inhibited the growth of A. gracilis; whereas after 72 and 96h, all the treatments except at 9.37mgL(-1) significantly affected the algae growth. The effective concentration 50 (EC50) after 96h was 22.44mgL(-1) of chlorpyrifos. After the exposure to the insecticide, an increase in the biovolume was observed, with a larger increase in cells exposed to 75 and 150mgL(-1). Radical changes were observed in the ultrastructure of cells exposed to chlorpyrifos. The insecticide affected the cell shape and the distribution of the crests in the wall. At 37.5mgL(-1) electodense bodies were observed along with an increase in the size and number of starch granules. At 150mgL(-1) such bodies occupied almost the whole cytoplasm together with lipids and remains of thylakoids. Autospores formation occurred normally at 37.5mgL(-1) while at 150mgL(-1) karyokinesis occurred, but cell-separation-phase was inhibited. The present study demonstrates that the exposure of phytoplankton to the insecticide chlorpyrifos leads to effects observed at both cellular and population level.
authors.affiliation: Laboratorio de Ecología Acuática, Depto. Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, B8000ICL Bahía Blanca, Argentina.
authors.forename: Viviana
authors.initials: V
authors.lastname: Asselborn
authors.affiliation: CONICET-BB-IADO (Instituto Argentino de Oceanografía), CC 804, B8000FWB Bahía Blanca, Argentina.
authors.forename: Carolina
authors.initials: C
authors.lastname: Fernández
authors.affiliation: CONICET-CECOAL (Centro de Ecología Aplicada del Litoral), CC 291, 3400 Corrientes, Argentina.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Zalocar
authors.affiliation: Laboratorio de Ecología Acuática, Depto. Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, B8000ICL Bahía Blanca, Argentina; CONICET-BB-IADO (Instituto Argentino de Oceanografía), CC 804, B8000FWB Bahía Blanca, Argentina. Electronic address: elipapers@criba.edu.ar.
authors.forename: Elisa R
authors.initials: ER
authors.lastname: Parodi
mesh_terms: D001681:Biological Assay; D000460:Chlorophyta / Q000187:drug effects* / Q000254:growth & development; D004390:Chlorpyrifos / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010839:Phytoplankton / Q000187:drug effects; D018675:Toxicity Tests
chemical_list: D007306:Insecticides; D004390:Chlorpyrifos
keywords: Microalgae; Pesticide; Toxicity; Ultrastructure