title: The effects of lead and copper on the cellular architecture and metabolism of the red alga Gracilaria domingensis.
abstract: The effect of lead and copper on apical segments of Gracilaria domingensis was examined. Over a period of 7 days, the segments were cultivated with concentrations of 5 and 10 ppm under laboratory conditions. The samples were processed for light, confocal, and electron microscopy, as well as histochemistry, to evaluate growth rates, mitochondrial activity, protein levels, chlorophyll a, phycobiliproteins, and carotenoids. After 7 days of exposure to lead and copper, growth rates were slower than control, and biomass loss was observed on copper-treated plants. Ultrastructural damage was primarily observed in the internal organization of chloroplasts and cell wall thickness. X-ray microanalysis detected lead in the cell wall, while copper was detected in both the cytoplasm and cell wall. Moreover, lead and copper exposure led to photodamage of photosynthetic pigments and, consequently, changes in photosynthesis. However, protein content and glutathione reductase activity decreased only in the copper treatments. In both treatments, decreased mitochondrial NADH dehydrogenase activity was observed. Taken together, the present study demonstrates that (1) heavy metals such as lead and copper negatively affect various morphological, physiological, and biochemical processes in G. domingensis and (2) copper is more toxic than lead in G. domingensis.
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, 88049-900, CP 476, Florianópolis, SC, Brazil.
authors.forename: Claudiane
authors.initials: C
authors.lastname: Gouveia
authors.forename: Marianne
authors.initials: M
authors.lastname: Kreusch
authors.forename: Éder C
authors.initials: ÉC
authors.lastname: Schmidt
authors.forename: Marthiellen R de L
authors.initials: MR
authors.lastname: Felix
authors.forename: Luz K P
authors.initials: LK
authors.lastname: Osorio
authors.forename: Debora T
authors.initials: DT
authors.lastname: Pereira
authors.forename: Rodrigo
authors.initials: R
authors.lastname: dos Santos
authors.forename: Luciane C
authors.initials: LC
authors.lastname: Ouriques
authors.forename: Roberta de Paula
authors.initials: Rde P
authors.lastname: Martins
authors.forename: Alexandra
authors.initials: A
authors.lastname: Latini
authors.forename: Fernanda
authors.initials: F
authors.lastname: Ramlov
authors.forename: Tiago José G
authors.initials: TJ
authors.lastname: Carvalho
authors.forename: Fungyi
authors.initials: F
authors.lastname: Chow
authors.forename: Marcelo
authors.initials: M
authors.lastname: Maraschin
authors.forename: Zenilda L
authors.initials: ZL
authors.lastname: Bouzon
mesh_terms: D018533:Biomass; D002338:Carotenoids / Q000032:analysis; D002473:Cell Wall / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D002736:Chloroplasts / Q000187:drug effects / Q000648:ultrastructure; D003300:Copper / Q000032:analysis / Q000633:toxicity*; D003593:Cytoplasm / Q000737:chemistry; D004577:Electron Probe Microanalysis; D044724:Gracilaria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D007854:Lead / Q000032:analysis / Q000633:toxicity*; D008853:Microscopy; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009245:NADH Dehydrogenase / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects; D052979:Phycobiliproteins / Q000032:analysis
chemical_list: D052979:Phycobiliproteins; D002734:Chlorophyll; D007854:Lead; D002338:Carotenoids; D003300:Copper; D009245:NADH Dehydrogenase; D000077194:Chlorophyll A