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Azevedo R, Rodriguez E, Mendes RJ, Mariz-Ponte N, Sario S, Lopes JC, Ferreira de Oliveira JMP, Santos C. Inorganic Hg toxicity in plants: A comparison of different genotoxic parameters. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 125:247-254. [PMID: 29477088 DOI: 10.1016/j.plaphy.2018.02.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/12/2018] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Inorganic Mercury (Hg) contamination persists an environmental problem, but its cyto- and genotoxicity in plants remains yet unquantified. To determine the extent of Hg-induced cyto- and genotoxicity, and assess most sensitive endpoints in plants, Pisum sativum L. seedlings were exposed for 14 days to different HgCl2 concentrations up to 100 μM. Shoots and roots from hydroponic exposure presented growth impairment and/or morphological disorders for doses >1 μM, being the roots more sensitive. Plant growth, ploidy changes, clastogenicity (HPCV), cell cycle dynamics (G1-S-G2), Comet-tail moment (TM), Comet-TD, Mitotic-index (MI) and cell proliferation index (CPI) were used to evaluate Hg-induced cyto/genotoxicity. Both leaf and root DNA-ploidy levels, assessed by flow cytometry (FCM), remained unaltered after exposure. Root cell cycle impairment occurred at lower doses (≥1 μM) than structural DNA damages (≥10 μM). Cytostatic effects depended on the Hg concentration, with delays during S-phase at lower doses, and arrests at G1 at higher ones. This arrest was paralleled with decreases of both mitotic index (MI) and cell proliferation index (CPI). DNA fragmentation, assessed by the Comet assay parameters of TD and TM, could be visualized for conditions ≥10 μM, while FCM-clastogenic parameter (FPCV) and micronuclei (MNC) were only altered in roots exposed to 100 μM. We demonstrate that inorganic-Hg induced cytostaticity is detectable even at 1 μM (a value found in contaminated sites), while structural DNA breaks/damage are only visualized in plants at concentrations ≥10 μM. We also demonstrate that among the different techniques tested for cyto- and genotoxicity, TD and TM Comet endpoints were more sensitive than FPCV or MNC. Regarding cytostatic effects, cell cycle analysis by FCM, including the difference in % cell cycle phases and CPI were more sensitive than MI or MNC frequency. Our data contribute to better understand Hg cyto- and genotoxicity in plants and to understand the information and sensitivity provided by each of the genotoxic techniques used.
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Affiliation(s)
- Raquel Azevedo
- Laboratory of Biotechnology and Cytomics, University of Aveiro, 3810-123, Aveiro, Portugal
| | - Eleazar Rodriguez
- Laboratory of Biotechnology and Cytomics, University of Aveiro, 3810-123, Aveiro, Portugal
| | - Rafael José Mendes
- iB(2)Lab, Department of Biology, Faculty of Sciences, LAQV/REQUIMTE, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal
| | - Nuno Mariz-Ponte
- iB(2)Lab, Department of Biology, Faculty of Sciences, LAQV/REQUIMTE, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal
| | - Sara Sario
- iB(2)Lab, Department of Biology, Faculty of Sciences, LAQV/REQUIMTE, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal
| | - José Carlos Lopes
- Department of Physics, University of Aveiro, 3810-123, Aveiro, Portugal
| | - José Miguel P Ferreira de Oliveira
- LAQV, REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, 4050-313, Porto, Portugal
| | - Conceição Santos
- iB(2)Lab, Department of Biology, Faculty of Sciences, LAQV/REQUIMTE, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal.
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Hou J, Zhou Y, Wang C, Li S, Wang X. Toxic Effects and Molecular Mechanism of Different Types of Silver Nanoparticles to the Aquatic Crustacean Daphnia magna. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:12868-12878. [PMID: 28968066 DOI: 10.1021/acs.est.7b03918] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Silver nanoparticles (AgNPs) have been assessed to have a high exposure risk for humans and aquatic organisms. Toxicity varies considerably between different types of AgNPs. This study aimed to investigate the toxic effects of AgNPs with different particle sizes (40 and 110 nm) and different surface coatings (sodium citrate and polyvinylpyrrolidone, PVP) on Daphnia magna and their mechanisms of action. The results revealed that the citrate-coated AgNPs were more toxic than PVP-coated AgNPs and that the 40 nm AgNPs were more toxic than the 110 nm AgNPs. Transcriptome analysis further revealed that the toxic effects of AgNPs on D. magna were related to the mechanisms of ion binding and several metabolic pathways, such as the "RNA polymerase" pathway and the "protein digestion and absorption" pathway. Moreover, the principal component analysis (PAC) results found that surface coating was the major factor that determines the toxicities compared to particle size. These results could help us better understand the possible mechanism of AgNP toxicity in aquatic invertebrates at the transcriptome level and establish an important foundation for revealing the broad impacts of nanoparticles on aquatic environments.
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Affiliation(s)
- Jing Hou
- College of Environmental Science and Engineering, North China Electric Power University , Beijing 102206, China
| | - Yue Zhou
- College of Environmental Science and Engineering, North China Electric Power University , Beijing 102206, China
| | - Chunjie Wang
- College of Environmental Science and Engineering, North China Electric Power University , Beijing 102206, China
| | - Shiguo Li
- Research Center for Eco-Environmental Sciences, Chinese Academy of Science , Beijing 100085, China
| | - Xiangke Wang
- College of Environmental Science and Engineering, North China Electric Power University , Beijing 102206, China
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