1
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Jaeger-Honz S, Klein K, Schreiber F. Systematic analysis, aggregation and visualisation of interaction fingerprints for molecular dynamics simulation data. J Cheminform 2024; 16:28. [PMID: 38475907 DOI: 10.1186/s13321-024-00822-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/02/2024] [Indexed: 03/14/2024] Open
Abstract
Computational methods such as molecular docking or molecular dynamics (MD) simulations have been developed to simulate and explore the interactions between biomolecules. However, the interactions obtained using these methods are difficult to analyse and evaluate. Interaction fingerprints (IFPs) have been proposed to derive interactions from static 3D coordinates and transform them into 1D bit vectors. More recently, the concept has been applied to derive IFPs from MD simulations, which adds a layer of complexity by adding the temporal motion and dynamics of a system. As a result, many IFPs are obtained from one MD simulation, resulting in a large number of individual IFPs that are difficult to analyse compared to IFPs derived from static 3D structures. Scientific contribution: We introduce a new method to systematically aggregate IFPs derived from MD simulation data. In addition, we propose visualisations to effectively analyse and compare IFPs derived from MD simulation data to account for the temporal evolution of interactions and to compare IFPs across different MD simulations. This has been implemented as a freely available Python library and can therefore be easily adopted by other researchers and to different MD simulation datasets.
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Affiliation(s)
- Sabrina Jaeger-Honz
- Department of Computer and Information Science, University of Konstanz, Universitätsstrasse 10, 78464, Constance, Germany.
| | - Karsten Klein
- Department of Computer and Information Science, University of Konstanz, Universitätsstrasse 10, 78464, Constance, Germany
| | - Falk Schreiber
- Department of Computer and Information Science, University of Konstanz, Universitätsstrasse 10, 78464, Constance, Germany
- Faculty of Information Technology, Monash University, Clayton, VIC, 3800, Australia
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2
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Shi JH, Olson NE, Birbeck JA, Pan J, Peraino NJ, Holen AL, Ledsky IR, Jacquemin SJ, Marr LC, Schmale DG, Westrick JA, Ault AP. Aerosolized Cyanobacterial Harmful Algal Bloom Toxins: Microcystin Congeners Quantified in the Atmosphere. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21801-21814. [PMID: 38078756 DOI: 10.1021/acs.est.3c03297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Cyanobacterial harmful algal blooms (cHABs) have the potential to adversely affect public health through the production of toxins such as microcystins, which consist of numerous molecularly distinct congeners. Microcystins have been observed in the atmosphere after emission from freshwater lakes, but little is known about the health effects of inhaling microcystins and the factors contributing to microcystin aerosolization. This study quantified total microcystin concentrations in water and aerosol samples collected around Grand Lake St. Marys (GLSM), Ohio. Microcystin concentrations in water samples collected on the same day ranged from 13 to 23 μg/L, dominated by the d-Asp3-MC-RR congener. In particulate matter <2.5 μm (PM2.5), microcystin concentrations up to 156 pg/m3 were detected; the microcystins were composed primarily of d-Asp3-MC-RR, with additional congeners (d-Asp3-MC-HtyR and d-Asp3-MC-LR) observed in a sample collected prior to a storm event. The PM size fraction containing the highest aerosolized MC concentration ranged from 0.44 to 2.5 μm. Analysis of total bacteria by qPCR targeting 16S rDNA revealed concentrations up to 9.4 × 104 gc/m3 in aerosol samples (≤3 μm), while a marker specific to cyanobacteria was not detected in any aerosol samples. Concentrations of aerosolized microcystins varied even when concentrations in water were relatively constant, demonstrating the importance of meteorological conditions (wind speed and direction) and aerosol generation mechanism(s) (wave breaking, spillway, and aeration systems) when evaluating inhalation exposure to microcystins and subsequent impacts on human health.
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Affiliation(s)
- Jia H Shi
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nicole E Olson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Johnna A Birbeck
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Jin Pan
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Nicholas J Peraino
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Andrew L Holen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Isabel R Ledsky
- Department of Chemistry, Carleton College, Northfield, Minnesota 55057, United States
| | - Stephen J Jacquemin
- Department of Biological Sciences, Wright State University, Lake Campus, Celina, Ohio 45822, United States
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - David G Schmale
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Judy A Westrick
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Andrew P Ault
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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3
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Guo X, Li Z, Jiang Q, Cheng C, Feng Y, He Y, Zuo L, Rao L, Ding W, Feng L. Structural insight into the substrate-binding mode and catalytic mechanism for MlrC enzyme of Sphingomonas sp. ACM-3962 in linearized microcystin biodegradation. Front Microbiol 2023; 14:1057264. [PMID: 36876080 PMCID: PMC9982164 DOI: 10.3389/fmicb.2023.1057264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/24/2023] [Indexed: 02/19/2023] Open
Abstract
Removing microcystins (MCs) safely and effectively has become an urgent global problem because of their extremely hazardous to the environment and public health. Microcystinases derived from indigenous microorganisms have received widespread attention due to their specific MC biodegradation function. However, linearized MCs are also very toxic and need to be removed from the water environment. How MlrC binds to linearized MCs and how it catalyzes the degradation process based on the actual three-dimensional structure have not been determined. In this study, the binding mode of MlrC with linearized MCs was explored using a combination of molecular docking and site-directed mutagenesis methods. A series of key substrate binding residues, including E70, W59, F67, F96, S392 and so on, were identified. Sodium dodecane sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze samples of these variants. The activity of MlrC variants were measured using high performance liquid chromatography (HPLC). We used fluorescence spectroscopy experiments to research the relationship between MlrC enzyme (E), zinc ion (M), and substrate (S). The results showed that MlrC enzyme, zinc ion and substrate formed E-M-S intermediates during the catalytic process. The substrate-binding cavity was made up of N and C-terminal domains and the substrate-binding site mainly included N41, E70, D341, S392, Q468, S485, R492, W59, F67, and F96. The E70 residue involved in both substrate catalysis and substrate binding. In conclusion, a possible catalytic mechanism of the MlrC enzyme was further proposed based on the experimental results and a literature survey. These findings provided new insights into the molecular mechanisms of the MlrC enzyme to degrade linearized MCs, and laid a theoretical foundation for further biodegradation studies of MCs.
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Affiliation(s)
- Xiaoliang Guo
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Zengru Li
- The Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Qinqin Jiang
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Cai Cheng
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Yu Feng
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Yanlin He
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Lingzi Zuo
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Li Rao
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Wei Ding
- The Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Lingling Feng
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
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4
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Turco L, Santori N, Buratti FM, Dorne JLCM, Testai E. Congeners-Specific Intestinal Absorption Of Microcystins In An In Vitro 3D Human Intestinal Epithelium: The Role Of Influx/Efflux Transporters. FRONTIERS IN TOXICOLOGY 2022; 4:883063. [PMID: 35990858 PMCID: PMC9388863 DOI: 10.3389/ftox.2022.883063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 03/28/2022] [Indexed: 11/18/2022] Open
Abstract
Microcystins constitute a group of over 200 variants and are increasingly considered as emerging toxins in food and feed safety, particularly with regards to sea-food and fish consumption. Toxicity of MCs is congener-specific, being characterised by different acute potencies, likely related to the differential activity of metabolic enzymes and transporters proteins involved in their cellular uptake. However, the active transport of MCs across intestinal membranes has not been fully elucidated. Our results, obtained using a fit for purpose 3D human reconstructed intestinal epithelium, provide new information on the complex mechanisms involved in the absorption of 5 MC variants’: it is indeed characterised by the equilibrium between uptake and extrusion, since the selected congeners are substrates of both influx and efflux proteins. In the range of tested nominal concentrations (10–40 µM) fully representative of relevant exposure scenarios, none of the active tested transporters were saturated. The comparison of permeability (Papp) values of MCs variants highlighted a dose independent relationship for MC-LR, -YR and -RR (Papp x 10–7 ranged from 2.95 to 3.54 cm/s), whereas -LW and–LF showed a dose dependent increase in permeability reaching Papp values which were similar to the other congeners at 40 µM. MC-RR, -LR, -YR show absorption values around 5% of the administered dose. Due to their lipophilicity, MC-LW and -LF were also detected within the cellular compartment. The intestinal uptake was only partially attributable to OATPs, suggesting the involvement of additional transporters. Regarding the efflux proteins, MCs are not P-gp substrates whereas MRP2 and to a lesser extent Breast cancer resistance protein are active in their extrusion. Despite the presence of GST proteins, as an indication of metabolic competence, in the intestinal tissue, MC-conjugates were never detected in our experimental settings.
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Affiliation(s)
- Laura Turco
- Istituto Superiore Di Sanità, Environment & Health Dept, Rome, Italy
- *Correspondence: Laura Turco,
| | - Nicoletta Santori
- Istituto Superiore Di Sanità, Environment & Health Dept, Rome, Italy
| | - Franca M. Buratti
- Istituto Superiore Di Sanità, Environment & Health Dept, Rome, Italy
| | | | - Emanuela Testai
- Istituto Superiore Di Sanità, Environment & Health Dept, Rome, Italy
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5
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Jaeger-Honz S, Nitschke J, Altaner S, Klein K, Dietrich DR, Schreiber F. Investigation of microcystin conformation and binding towards PPP1 by molecular dynamics simulation. Chem Biol Interact 2022; 351:109766. [PMID: 34861245 DOI: 10.1016/j.cbi.2021.109766] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 11/30/2022]
Abstract
Microcystins (MC) are a group of structurally similar cyanotoxins with currently 279 described structural variants. Human exposure is frequent by consumption of contaminated water, food or food supplements. MC can result in serious intoxications, commensurate with ensuing pathology in various organs or in rare cases even mortality. The current WHO risk assessment primarily considers MC-LR, while all other structural variants are treated as equivalent to MC-LR, despite that current data strongly suggest that MC-LR is not the most toxic MC, and toxicity can be very different for MC congeners. To investigate and analyse binding and conformation of different MC congeners, we applied for the first time Molecular Dynamics (MD) simulation to four MC congeners (MC-LR, MC-LF, [Enantio-Adda5]MC-LF, [β-D-Asp3,Dhb7]MC-RR). We could show that ser/thr protein phosphatase 1 is stable in all MD simulations and that MC-LR backbone adopts to a second conformation in solvent MD simulation, which was previously unknown. We could also show that MC congeners can adopt to different backbone conformation when simulated in solvent or in complex with ser/thr protein phosphatase 1 and differ in their binding behaviour. Our findings suggest that MD Simulation of different MC congeners aid in understanding structural differences and binding of this group of structurally similar cyanotoxins.
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Affiliation(s)
- Sabrina Jaeger-Honz
- Department of Computer and Information Science, University of Konstanz, Germany
| | - Jahn Nitschke
- Department of Biology, University of Konstanz, Germany
| | | | - Karsten Klein
- Department of Computer and Information Science, University of Konstanz, Germany
| | | | - Falk Schreiber
- Department of Computer and Information Science, University of Konstanz, Germany; Faculty of Information Technology, Monash University, Australia.
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6
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Qi J, Ma B, Miao S, Liu R, Hu C, Qu J. Pre-oxidation enhanced cyanobacteria removal in drinking water treatment: A review. J Environ Sci (China) 2021; 110:160-168. [PMID: 34593187 DOI: 10.1016/j.jes.2021.03.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 06/13/2023]
Abstract
Cyanobacterial bloom has many adverse effects on source water quality and drinking water production. The traditional water treatment process can hardly achieve satisfactory removal of algae cells. This review examines the impact of pre-oxidation on the removal of cyanobacteria by solid-liquid separation processes. It was reported that the introduction of chemical oxidants such as chlorine, potassium permanganate, and ozone in algae-laden water pretreatment could improve algae removal by the subsequent solid-liquid separation processes. However, over dosed oxidants can result in more serious water quality risks due to significant algae cell lysis and undesirable intracellular organic matter release. It was suggested that moderate pre-oxidation may enhance the removal of cyanobacteria without damaging algae cells. In this article, effects of moderate pretreatment on the solid-liquid separation processes (sedimentation, dissolved air flotation, and membrane filtration) are reviewed.
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Affiliation(s)
- Jing Qi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shiyu Miao
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruiping Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Chengzhi Hu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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7
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Wang J, Ren Y, Zheng X, Kang J, Huang Z, Xu L, Wang Y. Anti-Fibrotic Effects of Low Toxic Microcystin-RR on Bleomycin-Induced Pulmonary Fibrosis: A Comparison with Microcystin-LR. Front Pharmacol 2021; 12:675907. [PMID: 34168562 PMCID: PMC8217630 DOI: 10.3389/fphar.2021.675907] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/26/2021] [Indexed: 01/17/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial pulmonary disease characterized with radiographically evident pulmonary infiltrates and extracellular matrix deposition with limited treatment options. We previously described that microcystin-LR (MC-LR) reduces transforming growth factor (TGF)-β1/Smad signaling and ameliorates pulmonary fibrosis in bleomycin (BLM)-induced rat models. In the present study, we further demonstrate that microcystin-RR (MC-RR), an MC congener with lower toxicity than MC-LR, exerted an anti-fibrotic effect on BLM-induced pulmonary fibrosis rodent models and compared it with MC-LR. Our data show that MC-RR treatment attenuated BLM-associated pulmonary inflammation and collagen deposition in both therapeutic and preventive models. MC-RR reduced the expression of fibrotic markers, including vimentin, α-smooth muscle actin, collagen 1α1, and fibronectin, in rat pulmonary tissues. Furthermore, the core features of BLM-induced pulmonary fibrotic lesions were better alleviated by MC-RR than by MC-LR. MC-RR treatment substantially decreased the number of pulmonary M2 macrophages. In vitro, MC-RR attenuated the epithelial-mesenchymal transition and fibroblast-myofibroblast transition triggered by M2 macrophages. Therefore, we highlight MC-RR as a promising molecule for developing therapeutic and prophylactic strategies against IPF, a refractory lung disease.
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Affiliation(s)
- Jie Wang
- Department of Medical Genetics, Nanjing University School of Medicine, Nanjing, China.,Department of Tumor Biobank, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing Medical University Affiliated Cancer Hospital, Nanjing, China
| | - Yan Ren
- Department of Medical Genetics, Nanjing University School of Medicine, Nanjing, China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, China
| | - Xiufen Zheng
- Department of Pharmacy, The First Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Jiaqi Kang
- Department of Medical Genetics, Nanjing University School of Medicine, Nanjing, China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, China
| | - Zhenqian Huang
- Department of Medical Genetics, Nanjing University School of Medicine, Nanjing, China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, China
| | - Lizhi Xu
- Department of Medical Genetics, Nanjing University School of Medicine, Nanjing, China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, China
| | - Yaping Wang
- Department of Medical Genetics, Nanjing University School of Medicine, Nanjing, China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, China
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8
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Henri J, Lanceleur R, Delmas JM, Fessard V, Huguet A. Permeability of the Cyanotoxin Microcystin-RR across a Caco-2 Cells Monolayer. Toxins (Basel) 2021; 13:toxins13030178. [PMID: 33673481 PMCID: PMC7997155 DOI: 10.3390/toxins13030178] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 12/27/2022] Open
Abstract
Microcystins (MCs) are toxins produced by several cyanobacterial species found worldwide. While MCs have a common structure, the variation of two amino acids in their structure affects their toxicity. As toxicodynamics are very similar between the MC variants, their differential toxicity could rather be explained by toxicokinetic parameters. Microcystin-RR (MC-RR) is the second most abundant congener and induces toxicity through oral exposure. As intestinal permeability is a key parameter of oral toxicokinetics, the apparent permeability of MC-RR across a differentiated intestinal Caco-2 cell monolayer was investigated. We observed a rapid and large decrease of MC-RR levels in the donor compartment. However, irrespective of the loaded concentration and exposure time, the permeabilities were very low from apical to basolateral compartments (from 4 to 15 × 10−8 cm·s−1) and from basolateral to apical compartments (from 2 to 37 × 10−8 cm·s−1). Our results suggested that MC-RR would be poorly absorbed orally. As similar low permeability was reported for the most abundant congener microcystin-LR, and this variant presented a greater acute oral toxicity than MC-RR, we concluded that the intestinal permeability was probably not involved in the differential toxicity between them, in contrast to the hepatic uptake and metabolism.
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9
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Biales AD, Bencic DC, Flick RW, Delacruz A, Gordon DA, Huang W. Global transcriptomic profiling of microcystin-LR or -RR treated hepatocytes (HepaRG). Toxicon X 2020; 8:100060. [PMID: 33235993 PMCID: PMC7670210 DOI: 10.1016/j.toxcx.2020.100060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 12/20/2022] Open
Abstract
The canonical mode of action (MOA) of microcystins (MC) is the inhibition of protein phosphatases, but complete characterization of toxicity pathways is lacking. The existence of over 200 MC congeners complicates risk estimates worldwide. This work employed RNA-seq to provide an unbiased and comprehensive characterization of cellular targets and impacted cellular processes of hepatocytes exposed to either MC-LR or MC-RR congeners. The human hepatocyte cell line, HepaRG, was treated with three concentrations of MC-LR or -RR for 2 h. Significant reduction in cell survival was observed in LR1000 and LR100 treatments whereas no acute toxicity was observed in any MR-RR treatment. RNA-seq was performed on all treatments of MC-LR and -RR. Differentially expressed genes and pathways associated with oxidative and endoplasmic reticulum (ER) stress, and the unfolded protein response (UPR) were highly enriched by both congeners as were inflammatory pathways. Genes associated with both apoptotic and inflammatory pathways were enriched in LR1000. We present a model of MC toxicity that immediately causes oxidative stress and leads to ER stress and the activation of the UPR. Differential activation of the three arms of the UPR and the kinetics of JNK activation ultimately determine whether cell survival or apoptosis is favored. Extracellular exosomes were enrichment of by both congeners, suggesting a previously unidentified mechanism for MC-dependent extracellular signaling. The complement system was enriched only in MC-RR treatments, suggesting congener-specific differences in cellular effects. This study provided an unbiased snapshot of the early systemic hepatocyte response to MC-LR and MC-RR congeners and may explain differences in toxicity among MC congeners. Microcystin-LR and microcystin-RR have similar transcriptional responses. Genes associated with oxidative stress and the unfolded protein response were enriched by congeners. Genes associated with extracellular exosomes were enriched, suggesting a potential new mechanism for cell signaling. Complement associated genes were strongly enriched only by microcystin-RR. Identified a potential molecular mechanism underlying the cellular fate of hepatocyte.
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Affiliation(s)
- Adam D Biales
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - David C Bencic
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - Robert W Flick
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - Armah Delacruz
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - Denise A Gordon
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - Weichun Huang
- U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC, 27709, USA
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10
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Santori N, Buratti FM, Scardala S, Dorne JLCM, Testai E. In vitro detoxication of microcystins in human samples: variability among variants with different hydrophilicity and structure. Toxicol Lett 2020; 322:131-139. [PMID: 31953209 DOI: 10.1016/j.toxlet.2020.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/07/2020] [Accepted: 01/11/2020] [Indexed: 10/25/2022]
Abstract
Cyanotoxins, among which >200 variants of Microcystins (MC), constitute an emerging issue in food safety. Microcystins (MC) toxicity is congener-specific; however, the in vitro inhibition of PP1/PP2A (the key molecular event of MC toxicity) by single MC variants is comparable and MC toxicokinetics seems to be the critical point. Here, the variability in GSH conjugation catalysed by human recombinant enzymes and human hepatic cytosol has been compared between hydrophilic (MC-LR and MC-RR) and hydrophobic (MC-LW, MC-YR and MC-LF) variants, according to measured logPow. In vitro detoxication reaction (spontaneous plus enzymatic) is favored by the variant hydrophilicity, with MC-LF very poorly detoxified. With MC-YR and -LW the spontaneous reaction always gave the major contribution, whereas with MC-LR and -RR the enzymatic reaction became by far predominant when GSH was depleted. Consequently, the well-known GST polymorphisms seems not to be the major driver for potential human variability in susceptibility towards the MC-toxicity, except for MC-RR and -LR when GSH is depleted. Looking at these results and literature data, MC-RR (the least cytotoxic and acutely toxic in rodents) is the more hydrophilic, has the lowest OATP-mediated hepatic uptake and the highest detoxication efficiency. The opposite is true for the most lipophilic MC-LF: once entered in the cells with the highest uptake, it is very poorly detoxified, and resulted as the most toxic in various cell types. MC-dependent TK should be considered in order to estimate the variability in toxicity and to support the use of quantitative in vitro-in vivo extrapolation models of single toxins and their mixtures co-occurring in the environment.
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Affiliation(s)
- Nicoletta Santori
- Istituto Superiore Di Sanità, Environment & Health Dept., Viale Regina Elena, 299, Rome Italy
| | - Franca Maria Buratti
- Istituto Superiore Di Sanità, Environment & Health Dept., Viale Regina Elena, 299, Rome Italy.
| | - Simona Scardala
- Istituto Superiore Di Sanità, Environment & Health Dept., Viale Regina Elena, 299, Rome Italy
| | | | - Emanuela Testai
- Istituto Superiore Di Sanità, Environment & Health Dept., Viale Regina Elena, 299, Rome Italy
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11
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Bouaïcha N, Miles CO, Beach DG, Labidi Z, Djabri A, Benayache NY, Nguyen-Quang T. Structural Diversity, Characterization and Toxicology of Microcystins. Toxins (Basel) 2019; 11:toxins11120714. [PMID: 31817927 PMCID: PMC6950048 DOI: 10.3390/toxins11120714] [Citation(s) in RCA: 206] [Impact Index Per Article: 41.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 11/22/2022] Open
Abstract
Hepatotoxic microcystins (MCs) are the most widespread class of cyanotoxins and the one that has most often been implicated in cyanobacterial toxicosis. One of the main challenges in studying and monitoring MCs is the great structural diversity within the class. The full chemical structure of the first MC was elucidated in the early 1980s and since then, the number of reported structural analogues has grown steadily and continues to do so, thanks largely to advances in analytical methodology. The structures of some of these analogues have been definitively elucidated after chemical isolation using a combination of techniques including nuclear magnetic resonance, amino acid analysis, and tandem mass spectrometry (MS/MS). Others have only been tentatively identified using liquid chromatography-MS/MS without chemical isolation. An understanding of the structural diversity of MCs, the genetic and environmental controls for this diversity and the impact of structure on toxicity are all essential to the ongoing study of MCs across several scientific disciplines. However, because of the diversity of MCs and the range of approaches that have been taken for characterizing them, comprehensive information on the state of knowledge in each of these areas can be challenging to gather. We have conducted an in-depth review of the literature surrounding the identification and toxicity of known MCs and present here a concise review of these topics. At present, at least 279 MCs have been reported and are tabulated here. Among these, about 20% (55 of 279) appear to be the result of chemical or biochemical transformations of MCs that can occur in the environment or during sample handling and extraction of cyanobacteria, including oxidation products, methyl esters, or post-biosynthetic metabolites. The toxicity of many MCs has also been studied using a range of different approaches and a great deal of variability can be observed between reported toxicities, even for the same congener. This review will help clarify the current state of knowledge on the structural diversity of MCs as a class and the impacts of structure on toxicity, as well as to identify gaps in knowledge that should be addressed in future research.
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Affiliation(s)
- Noureddine Bouaïcha
- Écologie, Systématique et Évolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91405 Orsay, France; (A.D.); (N.Y.B.)
- Correspondence: ; Tel.: +33-(01)69154990; Fax: +33-(0)169155696
| | - Christopher O. Miles
- Biotoxin Metrology, National Research Council Canada, 1411 Oxford St, Halifax, NS B3H 3Z1, Canada; (C.O.M.); (D.G.B.)
| | - Daniel G. Beach
- Biotoxin Metrology, National Research Council Canada, 1411 Oxford St, Halifax, NS B3H 3Z1, Canada; (C.O.M.); (D.G.B.)
| | - Zineb Labidi
- Laboratoire Biodiversité et Pollution des Écosystèmes, Faculté des Sciences de la Nature et de la Vie, Université Chadli Bendjedid d’El Taref, 36000 El Taref, Algeria;
| | - Amina Djabri
- Écologie, Systématique et Évolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91405 Orsay, France; (A.D.); (N.Y.B.)
- Laboratoire Biodiversité et Pollution des Écosystèmes, Faculté des Sciences de la Nature et de la Vie, Université Chadli Bendjedid d’El Taref, 36000 El Taref, Algeria;
| | - Naila Yasmine Benayache
- Écologie, Systématique et Évolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91405 Orsay, France; (A.D.); (N.Y.B.)
| | - Tri Nguyen-Quang
- Biofluids and Biosystems Modeling (BBML), Faculty of Agriculture, Dalhousie University, 39 Cox Road, Truro, B2N 5E3 Nova Scotia, Canada;
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Birbeck JA, Peraino NJ, O’Neill GM, Coady J, Westrick JA. Dhb Microcystins Discovered in USA Using an Online Concentration LC-MS/MS Platform. Toxins (Basel) 2019; 11:E653. [PMID: 31717642 PMCID: PMC6891738 DOI: 10.3390/toxins11110653] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/01/2019] [Accepted: 11/03/2019] [Indexed: 11/16/2022] Open
Abstract
Based on current structural and statistical calculations, thousands of microcystins (MCs) can exist; yet, to date, only 246 MCs were identified and only 12 commercial MC standards are available. Standard mass spectrometry workflows for known and unknown MCs need to be developed and validated for basic and applied harmful algal bloom research to advance. Our investigation focuses on samples taken in the spring of 2018 from an impoundment fed by Oser and Bischoff Reservoirs, Indiana, United States of America (USA). The dominant cyanobacterium found during sampling was Planktothrix agardhii. The goal of our study was to identify and quantify the MCs in the impoundment sample using chemical derivatization and mass spectrometry. Modifying these techniques to use online concentration liquid chromatography tandem mass spectrometry (LC-MS/MS), two untargeted MCs have been identified, [d-Asp3, Dhb7]-MC-LR and [Dhb7]-MC-YR. [Dhb7]-MC-YR is not yet reported in the literature to date, and this was the first reported incidence of Dhb MCs in the United States. Furthermore, it was discovered that the commercially available [d-Asp3]-MC-RR standard was [d-Asp3, Dhb7]-MC-RR. This study highlights a workflow utilizing online concentration LC-MS/MS, high-resolution MS (HRMS), and chemical derivatization to identify isobaric MCs.
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Affiliation(s)
| | | | | | | | - Judy A. Westrick
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA; (J.A.B.); (N.J.P.); (G.M.O.); (J.C.)
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13
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Chen S, Zheng T, Ye C, Huannixi W, Yakefu Z, Meng Y, Peng X, Tian Z, Wang J, Ma Y, Yang Y, Ma Z, Zuo Z. Algicidal properties of extracts from Cinnamomum camphora fresh leaves and their main compounds. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 163:594-603. [PMID: 30077157 DOI: 10.1016/j.ecoenv.2018.07.115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/17/2018] [Accepted: 07/28/2018] [Indexed: 05/23/2023]
Abstract
Plant allelochemicals are considered as the source of effective, economic and friendly-environmental algaecides. To uncover the anti-algal activities of Cinnamomum camphora fresh leaves and their main algicidal agents, we investigated the inhibitory effects of water and methanol extracts from C. camphora fresh leaves on Microcystis aeruginosa and Chlamydomonas reinhardtii cell growth, analyzed the composition of the water and methanol extracts, and determined the main compounds in extracts on the growth of the two algae and their anti-algal mechanism from photosynthetic abilities. Water and methanol extracts from C. camphora fresh leaves can inhibit M. aeruginosa and C. reinhardtii cell growth, and methanol extracts showed stronger inhibitory effects, due to their more compounds and higher molar concentration. There were 23 compounds in the water extracts, mainly including terpenoids, esters, alcohols, and ketones. Compared to the water extracts, 9 new compounds were detected in the methanol extracts, and the molar concentration of total compounds in methanol extracts increased by 1.3 folds. Camphor, α-terpineol and linalool were 3 main compounds in the water and methanol extracts. Their mixture (1: 3: 6) and individual compound showed remarkable inhibition on M. aeruginosa and C. reinhardtii cell growth. The degradation of photosynthetic pigments and the reduction of maximum quantum yield of photosystem II (PSII) photochemistry, coefficient of photochemical quenching as well as apparent electron transport rate in C. reinhardtii cells aggravated gradually with increasing the concentration of the mixture and individual compound, while the non-photochemical dissipation of absorbed light energy increased gradually, which led to the decline of photosynthetic abilities. This indicated that camphor, α-terpineol and linalool were 3 main algicidal agents in C. camphora fresh leaf extracts, and they inhibited algal growth by inducing photosynthetic pigment degradation and declining PSII efficiency. Therefore, C. camphora fresh leaf extracts and their main components have potential utilization values as algaecides.
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Affiliation(s)
- Silan Chen
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Tiefeng Zheng
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Chaolin Ye
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Wulan Huannixi
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Zumulati Yakefu
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Yiyu Meng
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Xin Peng
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Zhengfeng Tian
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Junhao Wang
- Key Laboratory of Wood Science and Technology of Zhejiang Province, Zhejiang A & F University, Hangzhou 311300, China
| | - Yuandan Ma
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Youyou Yang
- Key Laboratory of Wood Science and Technology of Zhejiang Province, Zhejiang A & F University, Hangzhou 311300, China
| | - Zhongqing Ma
- Key Laboratory of Wood Science and Technology of Zhejiang Province, Zhejiang A & F University, Hangzhou 311300, China
| | - Zhaojiang Zuo
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China.
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14
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Zuo Z, Yang L, Chen S, Ye C, Han Y, Wang S, Ma Y. Effects of nitrogen nutrients on the volatile organic compound emissions from Microcystis aeruginosa. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 161:214-220. [PMID: 29885617 DOI: 10.1016/j.ecoenv.2018.05.095] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/24/2018] [Accepted: 05/30/2018] [Indexed: 06/08/2023]
Abstract
Cyanobacteria release abundant volatile organic compounds (VOCs), which can poison other algae and cause water odor. To uncover the effects of nitrogen (N) nutrients on the formation of cyanobacteria VOCs, the cell growth, VOC emission and the expression of genes involving in VOC formation in Microcystis aeruginosa were investigated under different N conditions. With the supplement of NaNO3, NaNO2, NH4Cl, urea, Serine (Ser) and Arginine (Arg) as the sole N source, NaNO3, urea and Arg showed the best effects on M. aeruginosa cell growth, and limited N supply inhibited the cell growth. M. aeruginosa released 26, 25, 23, 27, 23 and 25 compounds, respectively, in response to different N forms, including furans, sulfocompounds, terpenoids, benzenes, hydrocarbons, aldehydes, and esters. Low-N especially Non-N condition markedly promoted the VOC emission. Under Non-N condition, four up-regulated genes involving in VOC precursor formation were identified, including the genes of pyruvate kinase, malic enzyme and phosphotransacetylase for terpenoids, the gene of aspartate aminotransferase for benzenes and sulfocompounds. In eutrophic water, cyanobacteria release different VOC blends using various N forms, and the reduction of N amount caused by cyanobacteria massive growth can promote algal VOC emission by up-regulating the gene expression.
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Affiliation(s)
- Zhaojiang Zuo
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Hangzhou 311300, China.
| | - Lin Yang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Silan Chen
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Hangzhou 311300, China
| | - Chaolin Ye
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Hangzhou 311300, China
| | - Yujie Han
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Sutong Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Yuandan Ma
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Hangzhou 311300, China
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15
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Zuo Z, Yang Y, Xu Q, Yang W, Zhao J, Zhou L. Effects of phosphorus sources on volatile organic compound emissions from Microcystis flos-aquae and their toxic effects on Chlamydomonas reinhardtii. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2018; 40:1283-1298. [PMID: 29264818 DOI: 10.1007/s10653-017-0055-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 12/12/2017] [Indexed: 06/07/2023]
Abstract
There is diverse phosphorus (P) in eutrophicated waters, but it is considered as a crucial nutrient for cyanobacteria growth due to its easy precipitation as insoluble salts. To uncover the effects of complex P nutrients on the emission of volatile organic compounds (VOCs) from cyanobacteria and their toxic effects on other algae, the VOCs from Microcystis flos-aquae supplied with different types and amount of P nutrients were analyzed, and the effects of VOCs and their two main compounds on Chlamydomonas reinhardtii growth were investigated. When M. flos-aquae cells were supplied with K2HPO4, sodium pyrophosphate and sodium hexametaphosphate as the sole P source, 27, 23 and 29 compounds were found, respectively, including furans, sulfocompounds, terpenoids, benzenes, aldehydes, hydrocarbons and esters. With K2HPO4 as the sole P source, the VOC emission increased with reducing P amount, and the maximum emission was found under Non-P condition. In the treatments of M. flos-aquae VOCs under Non-P condition and two main terpenoids (eucalyptol and limonene) in the VOCs, remarkable decreases were found in C. reinhardtii cell growth, photosynthetic pigment content and photosynthetic abilities. Therefore, we deduce that multiple P nutrients in eutrophicated waters induce different VOC emissions from cyanobacteria, and P amount reduction caused by natural precipitation and algal massive growth results in more VOC emissions. These VOCs play toxic roles in cyanobacteria becoming dominant species, and eucalyptol and limonene are two toxic agents.
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Affiliation(s)
- Zhaojiang Zuo
- School of Forestry and Biotechnology, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China.
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.
| | - Youyou Yang
- College of Agriculture and Food Science, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Qinghuan Xu
- School of Forestry and Biotechnology, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Wangting Yang
- School of Forestry and Biotechnology, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Jingxian Zhao
- School of Forestry and Biotechnology, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Lv Zhou
- School of Forestry and Biotechnology, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
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16
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Yakefu Z, Huannixi W, Ye C, Zheng T, Chen S, Peng X, Tian Z, Wang J, Yang Y, Ma Z, Zuo Z. Inhibitory effects of extracts from Cinnamomum camphora fallen leaves on algae. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 77:2545-2554. [PMID: 29944120 DOI: 10.2166/wst.2018.199] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Natural allelochemicals are considered as a source of algaecides. To uncover the anti-algal activity of Cinnamomum camphora fallen leaves and promote their usage as algaecides, the composition of their water and methanol extracts was analyzed, and the inhibitory effects of extracts on the growth of Microcystis aeruginosa and Chlamydomonas reinhardtii, and chlorophyll (Chl) content and photosynthetic abilities in C. reinhardtii were investigated. Twenty-five compounds were detected in the water extracts, mainly including terpenoids, esters, alcohols, and ketones. Compared to water extracts, there were more compounds and higher concentration in methanol extracts. Both water and methanol extracts inhibited the growth of the two algae, and 15 mg·ml-1 methanol extracts killed the algal cells after 48 h. The levels of Chl a and Chl b, as well as maximum quantum yield of photosystem II photochemistry (Fv/Fm) in C. reinhardtii cells reduced gradually with increasing the concentration of extracts, while the maximum quantum yield of non-photochemical de-excitation (φDO) increased gradually. At the same concentration, methanol extracts showed stronger inhibitory effects than water extracts, due to their higher number of compounds and higher concentration. Therefore, C. camphora fallen leaves have a potential value as an algaecide.
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Affiliation(s)
- Zumulati Yakefu
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China E-mail:
| | - Wulan Huannixi
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China E-mail:
| | - Chaolin Ye
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China E-mail:
| | - Tiefeng Zheng
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China E-mail:
| | - Silan Chen
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China E-mail:
| | - Xin Peng
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China E-mail:
| | - Zhengfeng Tian
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China E-mail:
| | - Junhao Wang
- Key Laboratory of Wood Science and Technology of Zhejiang Province, Zhejiang A & F University, Hangzhou 311300, China
| | - Youyou Yang
- Key Laboratory of Wood Science and Technology of Zhejiang Province, Zhejiang A & F University, Hangzhou 311300, China
| | - Zhongqing Ma
- Key Laboratory of Wood Science and Technology of Zhejiang Province, Zhejiang A & F University, Hangzhou 311300, China
| | - Zhaojiang Zuo
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China E-mail:
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17
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Chen HQ, Zhao J, Li Y, He LX, Huang YJ, Shu WQ, Cao J, Liu WB, Liu JY. Gene expression network regulated by DNA methylation and microRNA during microcystin-leucine arginine induced malignant transformation in human hepatocyte L02 cells. Toxicol Lett 2018. [PMID: 29518473 DOI: 10.1016/j.toxlet.2018.03.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Microcystin (MC) is a cyclic heptapeptide compound which could lead to the development of hepatocellular carcinoma. However, the underlying epigenetic regulation mechanism is largely unknown. In this study, microcystin-LR (L: lysine, R: arginine, MC-LR) was used to induce the malignant transformation of human hepatocyte L02 cell line. The profile of gene expression, microRNA (miRNA) and DNA methylation were detected through high-throughput sequencing. Compared with control group, the expression of 826 genes and 187 miRNAs changed significantly in MC-LR treated group. DNA methylation sequencing analysis showed that 2592 CpG sites differentially methylated in promoter or the coding DNA sequence (CDS) of genes, while DNA methyltransferase 3 alpha (DNMT3a) and DNA methyltransferase 3 beta (DNMT3b) were dramatically up-regulated. Functional analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that significantly changed mRNAs and microRNAs were mainly involved in the formation of cancer, proliferation, invasion, migration and metabolism. MiRNA-mRNA network and mRNA-mRNA network analysis showed that hsa-miR-320a, hsa-miR-331-3p, hsa-miR-26a-5p, hsa-miR-196a-5p, hsa-miR-221-3p, coiled-coil domain containing 180 (CCDC180), melanoma antigen gene family member D1 (MAGED1), membrane spanning 4-domains A7 (MS4A7), hephaestin like 1 (HEPHL1), BH3 (Bcl-2 homology 3)-like motif containing, cell death inducer (BLID), matrix metallopeptidase 13 (MMP13), guanylate binding protein 5 (GBP5), adipogenesis regulatory factor (ADIRF), formin homology 2 domain containing 1 (FHDC1), protein kinase CAMP-dependent type II regulatory subunit beta (PRKAR2B), nodium leak channel, non-selective (NALCN), myosin light chain kinase 3 (MYLK3), epidermal growth factor receptor (EGFR) and zinc finger protein 704 (ZNF704) were key miRNAs and genes in the malignant transformation induced by MC-LR in L02 cells. Moreover, we found that expression of MYLK3, EGFR and ZNF704 were regulated by DNA methylation and miRNAs, and these genes affected the cell cycle and cell division. Our study suggested that characteristic gene alterations regulated by DNA methylation and miRNA could play an important role in environmental MC-LR induced hepatic carcinogenesis.
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Affiliation(s)
- Hong-Qiang Chen
- Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China
| | - Ji Zhao
- Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China; College of Public Health and Management, Ningxia Medical University, Yinchuan 750004, PR China
| | - Yan Li
- Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China; The Calmette International Hospital, Kunming 650224, PR China
| | - Li-Xiong He
- Department of Environmental Hygiene, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China
| | - Yu-Jing Huang
- Department of Environmental Hygiene, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China
| | - Wei-Qun Shu
- Department of Environmental Hygiene, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China
| | - Jia Cao
- Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China
| | - Wen-Bin Liu
- Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China.
| | - Jin-Yi Liu
- Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, PR China.
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18
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Microcystins: Synthesis and structure–activity relationship studies toward PP1 and PP2A. Bioorg Med Chem 2018; 26:1118-1126. [DOI: 10.1016/j.bmc.2017.08.040] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/19/2017] [Accepted: 08/23/2017] [Indexed: 11/19/2022]
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19
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Production of a bisdemethylated microcystin variant by Planktothrix rubescens. Toxicon 2017; 137:95-98. [PMID: 28668563 DOI: 10.1016/j.toxicon.2017.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/31/2017] [Accepted: 06/28/2017] [Indexed: 11/20/2022]
Abstract
Reservoir samples from a bloom of Planktothrix rubescens were analyzed by ELISA and LC-MS/MS. The comparison of the results of both methods points to the presence of a microcystin variant not yet available as analytical standard and therefore, not detectable by LC-MS/MS analysis. It is proposed that the unknown cyanotoxin variant is a bisdemethylated microcystin variant, presumably [Asp3,Dha7]-microcystin-RR. [Asp3,Dha7]-MC-RR has not been described for a bloom of P. rubescens before.
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20
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Buratti FM, Manganelli M, Vichi S, Stefanelli M, Scardala S, Testai E, Funari E. Cyanotoxins: producing organisms, occurrence, toxicity, mechanism of action and human health toxicological risk evaluation. Arch Toxicol 2017; 91:1049-1130. [DOI: 10.1007/s00204-016-1913-6] [Citation(s) in RCA: 258] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/13/2016] [Indexed: 12/11/2022]
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21
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Xu Q, Yang L, Yang W, Bai Y, Hou P, Zhao J, Zhou L, Zuo Z. Volatile organic compounds released from Microcystis flos-aquae under nitrogen sources and their toxic effects on Chlorella vulgaris. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2017; 135:191-200. [PMID: 27741460 DOI: 10.1016/j.ecoenv.2016.09.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 09/26/2016] [Accepted: 09/27/2016] [Indexed: 06/06/2023]
Abstract
Eutrophication promotes massive growth of cyanobacteria and algal blooms, which can poison other algae and reduce biodiversity. To investigate the differences in multiple nitrogen (N) sources in eutrophicated water on the emission of volatile organic compounds (VOCs) from cyanobacteria, and their toxic effects on other algal growth, we analyzed VOCs emitted from Microcystis flos-aquae with different types and concentrations of nitrogen, and determined the effects under Normal-N and Non-N conditions on Chlorella vulgaris. M. flos-aquae released 27, 22, 20, 27, 19, 25 and 17 compounds, respectively, with NaNO3, NaNO2, NH4Cl, urea, Ser, Lys and Arg as the sole N source. With the reduction in N amount, the emission of VOCs was increased markedly, and the most VOCs were found under Non-N condition. C. vulgaris cell propagation, photosynthetic pigment and Fv/Fm declined significantly following exposure to M. flos-aquae VOCs under Non-N condition, but not under Normal-N condition. When C. vulgaris cells were treated with two terpenoids, eucalyptol and limonene, the inhibitory effects were enhanced with increasing concentrations. Therefore, multiple N sources in eutrophicated water induce different VOC emissions from cyanobacteria, and reduction in N can cause nutrient competition, which can result in emissions of more VOCs. Those VOCs released from M. flos-aquae cells under Non-N for nutrient competition can inhibit other algal growth. Among those VOCs, eucalyptol and limonene are the major toxic agents.
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Affiliation(s)
- Qinghuan Xu
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Lin'an 311300, China
| | - Lin Yang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Wangting Yang
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Lin'an 311300, China
| | - Yan Bai
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Lin'an 311300, China
| | - Ping Hou
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Lin'an 311300, China
| | - Jingxian Zhao
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Lin'an 311300, China
| | - Lv Zhou
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Lin'an 311300, China
| | - Zhaojiang Zuo
- School of Forestry and Biotechnology, Zhejiang Agriculture & Forestry University, Lin'an 311300, China; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing 48824, USA.
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22
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miR-541 Contributes to Microcystin-LR-Induced Reproductive Toxicity through Regulating the Expression of p15 in Mice. Toxins (Basel) 2016; 8:toxins8090260. [PMID: 27608041 PMCID: PMC5037486 DOI: 10.3390/toxins8090260] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 08/31/2016] [Indexed: 12/31/2022] Open
Abstract
Microcystin-leucine arginine (MC-LR) is a harmful cyanotoxin produced by cyanobacteria. MC-LR can exert endocrine-disrupting activities in many organisms. We have previously demonstrated that MC-LR exerts both acute and chronic reproductive toxicity in male mice, resulting in a decline in sperm quality and damage to testicular structure. Moreover, we also observed extensive alterations in a panel of microRNAs in spermatogonial cells after exposure to MC-LR. In this study, we have confirmed that miR-541 was significantly increased both in GC-1 cells (in vitro) and in mouse testes (in vivo) after exposure to MC-LR. Our data support that p15 was the target gene of miR-541. Increase in miR-541 led to a reduction of p15 and murine double minute2 (MDM2), promoting the activation of p53 signaling and MC-LR-mediated cell apoptosis. Moreover, cells responded to MC-LR with reduced viability and increased apoptosis. Consistently, inhibiting miR-541 could upregulate the expression of p15 and MDM2, resulting in the downregulation of phospho-p53. Downregulation of miR-541 promoted cell viability by reducing MC-LR-induced cell apoptosis. In conclusion, we demonstrate here a crucial role for miR-541 in MC-LR-induced toxic effects on the reproductive system, in an attempt to provide a rational strategy for the diagnosis and treatment of MC-LR-induced impairment in the reproductive system.
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23
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Le Manach S, Khenfech N, Huet H, Qiao Q, Duval C, Marie A, Bolbach G, Clodic G, Djediat C, Bernard C, Edery M, Marie B. Gender-Specific Toxicological Effects of Chronic Exposure to Pure Microcystin-LR or Complex Microcystis aeruginosa Extracts on Adult Medaka Fish. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8324-8334. [PMID: 27409512 DOI: 10.1021/acs.est.6b01903] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Cyanobacterial blooms often occur in freshwater lakes and constitute a potential health risk to human populations, as well as to other organisms. However, their overall and specific implications for the health of aquatic organisms that are chronically and environmentally exposed to cyanobacteria producing hepatotoxins, such as microcystins (MCs), together with other bioactive compounds have still not been clearly established and remain difficult to assess. The medaka fish was chosen as the experimental aquatic model for studying the cellular and molecular toxicological effects on the liver after chronic exposures (28 days) to environmentally relevant concentrations of pure MC-LR, complex extracts of MC producing or nonproducing cyanobacterial biomasses, and of a Microcystis aeruginosa natural bloom. Our results showed a higher susceptibility of females to the different treatments compared to males at both the cellular and the molecular levels. Although hepatocyte lysis increased with MC-containing treatments, lysis always appeared more severe in the liver of females compare to males, and the glycogen cellular reserves also appeared to decrease more in the liver of females compared to those in the males. Proteomic investigations reveal divergent responses between males and females exposed to all treatments, especially for proteins involved in metabolic and homeostasis processes. Our observations also highlighted the dysregulation of proteins involved in oogenesis in female livers. These results suggest that fish populations exposed to cyanobacteria blooms may potentially face several ecotoxicological issues.
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Affiliation(s)
- Séverine Le Manach
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
| | - Nour Khenfech
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
| | - Hélène Huet
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
- Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est , BioPôle Alfort, 94700 Maison-Alfort, France
| | - Qin Qiao
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
| | - Charlotte Duval
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
| | - Arul Marie
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
| | - Gérard Bolbach
- Institut de Biologie Paris Seine/FR 3631, Plateforme Spectrométrie de masse et Protéomique, Sorbonne Universités, Université Pierre et Marie Curie , 75005 Paris, France
| | - Gilles Clodic
- Institut de Biologie Paris Seine/FR 3631, Plateforme Spectrométrie de masse et Protéomique, Sorbonne Universités, Université Pierre et Marie Curie , 75005 Paris, France
| | - Chakib Djediat
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
| | - Cécile Bernard
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
| | - Marc Edery
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
| | - Benjamin Marie
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Sorbonne Universités, Muséum National d'Histoire Naturelle , CP 39, 12 Rue Buffon, 75005 Paris, France
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Eguzozie K, Mavumengwana V, Nkosi D, Kayitesi E, Nnabuo-Eguzozie EC. Bioaccumulation and Quantitative Variations of Microcystins in the Swartspruit River, South Africa. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2016; 71:286-296. [PMID: 26936473 DOI: 10.1007/s00244-016-0269-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 02/06/2016] [Indexed: 06/05/2023]
Abstract
The bioaccumulation and quantitative variations of cyanobacterial peptide hepatotoxin intracellular microcystin in floating scums of cyanobacterium microcystis flos aquae collected from predetermined sampling sites in the Swartspruit River was investigated. Three distinct MCs variants (MC-YR, MC-LR, and MC-RR) were isolated, identified, and quantified. Additionally, two minor microcystin congeners (MC-(H4) YR), (D-Asp(3), Dha(7))MC-RR) also were identified but were not quantified. Quantitative analysis was achieved using peak areas substituted on linear regression equations: Y = 10085x - 19698 (R (2) = 0.9998), Y = 201387x + 20328 (R (2) = 0.9929), Y = 2506x + 15659 (R (2) = 0.9999), and 9859x + 208694 (R (2) = 0.9929) of standard curves for 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 μg/mL MC-LR, MC-RR, MC-YR respectively. Variant dominance followed the order MC-LR > MC-RR > MC-YR across the sampling sites. Analysis of maximum and minimum concentrations of quantified MCs variants showed 270.7, 14.10 (µg/g), 141.5, 1.43 (µg/g), and 72.28, 0.15 (µg/g) for MC-LR, MC-RR, and MC-YR, respectively. This implies there was quantitative variations of microcystin congeners across the sampled sites. Significant differences between means were assessed by an analysis of variance with P < 0.05 being considered significant. Results showed that there were no significant difference between mean MCs concentrations across the sampling periods (P > 0.05) and significant difference between mean MCs concentrations across sampling sites (P < 0.05).
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Affiliation(s)
- Kennedy Eguzozie
- Department of Biotechnology and Food Technology, University of Johannesburg, Johannesburg, South Africa.
| | - Vuyo Mavumengwana
- Department of Biotechnology and Food Technology, University of Johannesburg, Johannesburg, South Africa
| | - Duduzile Nkosi
- Department of Applied Chemistry, Faculty of Science, University of Johannesburg, Johannesburg, South Africa
| | - Eugenie Kayitesi
- Department of Biotechnology and Food Technology, University of Johannesburg, Johannesburg, South Africa
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25
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Paerl HW, Otten TG, Joyner AR. Moving towards adaptive management of cyanotoxin-impaired water bodies. Microb Biotechnol 2016; 9:641-51. [PMID: 27418325 PMCID: PMC4993183 DOI: 10.1111/1751-7915.12383] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 06/23/2016] [Indexed: 11/30/2022] Open
Abstract
The cyanobacteria are a phylum of bacteria that have played a key role in shaping the Earth's biosphere due to their pioneering ability to perform oxygenic photosynthesis. Throughout their history, cyanobacteria have experienced major biogeochemical changes accompanying Earth's geochemical evolution over the past 2.5+ billion years, including periods of extreme climatic change, hydrologic, nutrient and radiation stress. Today, they remain remarkably successful, exploiting human nutrient over‐enrichment as nuisance “blooms.” Cyanobacteria produce an array of unique metabolites, the functions and biotic ramifications of which are the subject of diverse ecophysiological studies. These metabolites are relevant from organismal and ecosystem function perspectives because some can be toxic and fatal to diverse biota, including zooplankton and fish consumers of algal biomass, and high‐level consumers of aquatic food sources and drinking water, including humans. Given the long history of environmental extremes and selection pressures that cyanobacteria have experienced, it is likely that that these toxins serve ecophysiological functions aimed at optimizing growth and fitness during periods of environmental stress. Here, we explore the molecular and ecophysiological mechanisms underlying cyanotoxin production, with emphasis on key environmental conditions potentially controlling toxin production. Based on this information, we offer potential management strategies for reducing cyanotoxin potentials in natural waters; for cyanotoxins with no clear drivers yet elucidated, we highlight the data gaps and research questions that are still lacking. We focus on the four major classes of toxins (anatoxins, cylindrospermopsins, microcystins and saxitoxins) that have thus far been identified as relevant from environmental health perspectives, but caution there may be other harmful metabolites waiting to be elucidated.
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Affiliation(s)
- Hans W Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, USA
| | - Timothy G Otten
- Bend Genetics, LLC, 87 Scripps Drive, Ste. 301, Sacramento, CA, USA
| | - Alan R Joyner
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, USA
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Miles CO, Sandvik M, Nonga HE, Ballot A, Wilkins AL, Rise F, Jaabaek JAH, Loader JI. Conjugation of Microcystins with Thiols Is Reversible: Base-Catalyzed Deconjugation for Chemical Analysis. Chem Res Toxicol 2016; 29:860-70. [DOI: 10.1021/acs.chemrestox.6b00028] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Morten Sandvik
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106 Oslo, Norway
| | - Hezron E. Nonga
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106 Oslo, Norway
| | - Andreas Ballot
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106 Oslo, Norway
| | - Alistair L. Wilkins
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106 Oslo, Norway
- Chemistry Department, University of Waikato, Private Bag 3105, 3240 Hamilton, New Zealand
| | - Frode Rise
- Department
of Chemistry, University of Oslo, P.O. Box 1033, N-0315 Oslo, Norway
| | - J. Atle H. Jaabaek
- Department
of Chemistry, University of Oslo, P.O. Box 1033, N-0315 Oslo, Norway
| | - Jared I. Loader
- AgResearch Ltd., Ruakura Research Centre, Bisley Road, Private Bag 3123, Hamilton 3240, New Zealand
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Liu J, Van Oosterhout E, Faassen EJ, Lürling M, Helmsing NR, Van de Waal DB. ElevatedpCO2causes a shift towards more toxic microcystin variants in nitrogen-limitedMicrocystis aeruginosa. FEMS Microbiol Ecol 2015; 92:fiv159. [DOI: 10.1093/femsec/fiv159] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2015] [Indexed: 11/12/2022] Open
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Mechanisms of microcystin-LR-induced cytoskeletal disruption in animal cells. Toxicon 2015; 101:92-100. [DOI: 10.1016/j.toxicon.2015.05.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 05/06/2015] [Accepted: 05/12/2015] [Indexed: 12/31/2022]
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Steiner K, Zimmermann L, Hagenbuch B, Dietrich D. Zebrafish Oatp-mediated transport of microcystin congeners. Arch Toxicol 2015; 90:1129-39. [PMID: 26055554 DOI: 10.1007/s00204-015-1544-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/28/2015] [Indexed: 01/07/2023]
Abstract
Microcystins (MC), representing >100 congeners being produced by cyanobacteria, are a hazard for aquatic species. As MC congeners vary in their toxicity, the congener composition of a bloom primarily dictates the severity of adverse effects and appears primarily to be governed by toxicokinetics, i.e., whether transport of MCs occurs via organic anion-transporting polypeptides (Oatps). Differences in observed MC toxicity in various fish species suggest differential expression of Oatp subtypes leading to varying tissue distribution of the very same MC congener within different species. The objectives of this study were the functional characterization and analysis of the tissue distribution of Oatp subtypes in zebrafish (Danio rerio) as a surrogate model for cyprinid fish. Zebrafish Oatps (zfOatps) were cloned, and the organ distribution was determined at the mRNA level. zfOatps were transiently expressed in HEK293 cells for functional characterization using the Oatp substrates estrone-3-sulfate, taurocholate and methotrexate and specific MC congeners (MC-LR, MC-RR, MC-LF and MC-LW). Novel zfOatp isoforms were isolated. Among these isoforms, the organ-specific expression of zfOatp1d1 and of members of the zfOatp1f subfamily was identified. At the functional level, zfOatp1d1, zfOatp1f2, zfOatp1f3 and zfOatp1f4 transported at least one of the Oatp substrates, and zfOatp1d1, zfOatp1f2 and zfOatp1f4 were shown to transport MC congeners. MC-LF and MC-LW were generally transported faster than MC-LR and MC-RR. The subtype-specific expression of zfOatp1d1 and of members of the zfOatp1f subfamily as well as differences in the transport of MC congeners could explain the MC congener-dependent differences in toxicity in cyprinids.
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Affiliation(s)
- Konstanze Steiner
- Human and Environmental Toxicology, Department of Biology, University of Konstanz, PO BOX 662, 78457, Constance, Germany
| | - Lisa Zimmermann
- Human and Environmental Toxicology, Department of Biology, University of Konstanz, PO BOX 662, 78457, Constance, Germany
| | - Bruno Hagenbuch
- Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS, USA
| | - Daniel Dietrich
- Human and Environmental Toxicology, Department of Biology, University of Konstanz, PO BOX 662, 78457, Constance, Germany.
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Buratti FM, Testai E. Species- and congener-differences in microcystin-LR and -RR GSH conjugation in human, rat, and mouse hepatic cytosol. Toxicol Lett 2015; 232:133-40. [DOI: 10.1016/j.toxlet.2014.10.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
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Heussner AH, Altaner S, Kamp L, Rubio F, Dietrich DR. Pitfalls in microcystin extraction and recovery from human blood serum. Chem Biol Interact 2014; 223:87-94. [DOI: 10.1016/j.cbi.2014.08.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 08/20/2014] [Accepted: 08/22/2014] [Indexed: 10/24/2022]
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32
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Comparison of two ELISA-based methods for the detection of microcystins in blood serum. Chem Biol Interact 2014; 223:10-7. [DOI: 10.1016/j.cbi.2014.08.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 08/26/2014] [Accepted: 08/29/2014] [Indexed: 11/24/2022]
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Callieri C, Bertoni R, Contesini M, Bertoni F. Lake level fluctuations boost toxic cyanobacterial "oligotrophic blooms". PLoS One 2014; 9:e109526. [PMID: 25295866 PMCID: PMC4190310 DOI: 10.1371/journal.pone.0109526] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 09/01/2014] [Indexed: 11/18/2022] Open
Abstract
Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii ( = planktonic Anabaena), a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D. lemmermannii population. The highest percentage of P release and the lowest C:P molar ratio of released nutrients coincided with the summer appearance of the D. lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms.
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Affiliation(s)
| | | | | | - Filippo Bertoni
- Centre for Social Science and Global Health – University of Amsterdam, Amsterdam, The Netherlands
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Garibo D, Flores C, Cetó X, Prieto-Simón B, Del Valle M, Caixach J, Diogène J, Campàs M. Inhibition equivalency factors for microcystin variants in recombinant and wild-type protein phosphatase 1 and 2A assays. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:10652-60. [PMID: 24870287 DOI: 10.1007/s11356-014-3065-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 05/20/2014] [Indexed: 05/21/2023]
Abstract
In this work, protein phosphatase inhibition assays (PPIAs) have been used to evaluate the performance of recombinant PP1 and recombinant and wild-type PP2As. The enzymes have been compared using microcystins-LR (MC-LR) as a model cyanotoxin. Whereas PP2ARec provides a limit of detection (LOD) of 3.1 μg/L, PP1Rec and PP2AWild provide LODs of 0.6 and 0.5 μg/L, respectively, lower than the guideline value proposed by the World Health Organization (1 μg/L). The inhibitory potencies of seven MC variants (-LR, -RR, -dmLR, -YR, -LY, -LW and -LF) have been evaluated, resulting on 50 % inhibition coefficient (IC50) values ranging from 1.4 to 359.3 μg/L depending on the MC variant and the PP. The PPIAs have been applied to the determination of MC equivalent contents in a natural cyanobacterial bloom and an artificially contaminated sample, with multi-MC profiles. The inhibition equivalency factors (IEFs) have been applied to the individual MC quantifications determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and the estimated MC-LR equivalent content has been compared to PPIA results. PPIAs have demonstrated to be applicable as MC screening tools for environmental applications and to protect human and animal health.
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Affiliation(s)
- Diana Garibo
- IRTA, Carretera de Poble Nou km 5.5, 43540, Sant Carles de la Ràpita, Spain
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Ostermaier V, Christiansen G, Schanz F, Kurmayer R. Genetic variability of microcystin biosynthesis genes in Planktothrix as elucidated from samples preserved by heat desiccation during three decades. PLoS One 2013; 8:e80177. [PMID: 24265798 PMCID: PMC3827215 DOI: 10.1371/journal.pone.0080177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/09/2013] [Indexed: 11/23/2022] Open
Abstract
Historic samples of phytoplankton can provide information on the abundance of the toxigenic genotypes of cyanobacteria in dependence on increased or decreased eutrophication. The analysis of a time-series from preserved phytoplankton samples by quantitative PCR (qPCR) extends observation periods considerably. The analysis of DNA from heat-desiccated samples by qPCR can be aggravated by point substitutions or the fragmentation of DNA introduced by the high temperature. In this study, we analyzed whether the heat desiccation of the cellular material of the cyanobacterium Planktothrix sp. introduced potential errors to the template DNA that is used for qPCR within (i) 16S rDNA and phycocyanin genes and (ii) the mcyA gene indicative of the incorporation of either dehydrobutyrine (Dhb) or N-methyl-dehydroalanine (Mdha) in position 7, and (ii) the mcyB gene, which is indicative of homotyrosine (Hty) in position 2 of the microcystin (MC) molecule. Due to high temperature desiccation, the deterioration of the DNA template quality was rather due to fragmentation than due to nucleotide substitutions. By using the heat-desiccated samples of Lake Zürich, Switzerland the abundance of the Dhb, Mdha and Hty genotypes was determined during three decades (1977-2008). Despite major changes in the trophic state of the lake resulting in a major increase of the total Planktothrix population density, the proportion of these genotypes encoding the synthesis of different MC congeners showed high stability. Nevertheless, a decline of the most abundant mcyA genotype indicative of the synthesis of Dhb in position 7 of the MC molecule was observed. This decline could be related to the gradual incline in the proportion of a mutant genotype carrying a 1.8kbp deletion of this gene region. The increase of this mcyA (Dhb) gene deletion mutant has been minor so far, however, and likely did not affect the overall toxicity of the population.
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Affiliation(s)
| | | | - Ferdinand Schanz
- Limnological Station, Institute of Plant Biology, University of Zürich, Kilchberg, Switzerland
| | - Rainer Kurmayer
- Research Institute for Limnology, University of Innsbruck, Mondsee, Austria
- * E-mail:
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The conjugation of microcystin-RR by human recombinant GSTs and hepatic cytosol. Toxicol Lett 2013; 219:231-8. [DOI: 10.1016/j.toxlet.2013.03.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/15/2013] [Accepted: 03/18/2013] [Indexed: 01/18/2023]
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Quantitative variations of intracellular microcystin-LR, -RR and -YR in samples collected from four locations in Hartbeespoort Dam in North West Province (South Africa) during the 2010/2011 summer season. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2012. [PMID: 23202758 PMCID: PMC3509467 DOI: 10.3390/ijerph9103484] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Hartbeespoort (HBP) Dam is a reservoir used for agricultural, domestic supply of raw potable water and recreational activities in South Africa’s North-West Province. Eutrophication and cyanobacterial blooms have long been a cause of water-quality problems in this reservoir. The most prevalent bloom-forming species is Microcystis aeruginosa, often producing the toxin microcystin, a hepatotoxin which can negatively impact aquatic animal and human health, and poses a problem for potable water supply. Algal samples were collected monthly from four pre-determined sites in the dam during the summer months (December 2010–March 2011). Intracellular microcystins (MCs) were extracted using SPE C18 cartridges, followed by separation, identification and quantification using LC-ESI-MS techniques. Quantitative variation studies of MCs were conducted with respect to MC congener isolated, sampling site and month. Three main MC congeners (MC-RR, -LR and-YR) were isolated, identified and quantified. In addition, three minor MCs (MC-WR, MC-(H4)YR and (D-Asp3, Dha7)MC-RR were also identified, but were not quantified. The MC dominance followed the order MC-RR>MC-LR>MC-YR across all sites and time. The maximum and minimum concentrations were 268 µg/g and 0.14 µg/g DW for MC-RR and MC-YR, respectively, of the total MCs quantified from this study. One-way ANOVA showed that there were no significant differences between average MC concentrations recorded across months (P = 0.62), there was, however, a marginally-significant difference in concentrations among MC congeners (P = 0.06). ANCOVA revealed a highly significant interaction between sites and MC congeners on MC concentration (P < 0.001).
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Guzmán-Guillén R, Prieto AI, González AG, Soria-Díaz ME, Cameán AM. Cylindrospermopsin determination in water by LC-MS/MS: optimization and validation of the method and application to real samples. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2012; 31:2233-2238. [PMID: 22825923 DOI: 10.1002/etc.1954] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 02/28/2012] [Accepted: 06/07/2012] [Indexed: 06/01/2023]
Abstract
A new method for determining dissolved cylindrospermopsin (CYN) in waters using solid-phase extraction (SPE) with graphitized carbon cartridges and quantification by liquid chromatography coupled with tandem mass spectrometry is described and discussed. The method has been suitably validated: the linear range covered is from 0.900 to 125 µg CYN/L. Limits of detection and quantification were 0.5 and 0.9 µg CYN/L, respectively, and allow CYN determination at concentrations below the guideline proposed of 1 µg CYN/L in natural waters. The method exhibits mean recoveries from 83 to 95%, and intermediate precision (relative standard deviation (%)) values from 5 to 12%, ensuring adequacy against the Association of Official Analytical Chemists guidelines. The method is robust against the following three influential factors considered in the cleanup stage: the batch of the graphitized carbon cartridges, the flow rate of the water sample through the cartridge, and the final redissolved water volume after SPE treatment. The method has been successfully applied to detection and quantification of CYN in water samples from aquaria of a toxicological in vivo laboratory experiment.
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Zeller P, Quenault H, Huguet A, Blanchard Y, Fessard V. Transcriptomic comparison of cyanotoxin variants in a human intestinal model revealed major differences in oxidative stress response: effects of MC-RR and MC-LR on Caco-2 cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 82:13-21. [PMID: 22721844 DOI: 10.1016/j.ecoenv.2012.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 04/30/2012] [Accepted: 05/03/2012] [Indexed: 06/01/2023]
Abstract
Microcystins (MCs) are cyclic hepatotoxins produced by various species of cyanobacteria. Their structure includes two variable amino acids (AA) giving rise to more than 90 MC variants, however most of the studies to date have focused on the most toxic variant: microcystin LR (MC-LR). Ingestion is the major route of human exposure to MCs and several in vivo studies have demonstrated macroscopic effects on the gastro-intestinal tract. However, little information exists concerning the pathways affected by MC variants on intestinal cells. In the current study, we have investigated the effects of MC-RR and MC-LR on the human intestinal cell line Caco-2 using a non-selective method and compared their response at the pangenomic scale. The cells were incubated for 4h or 24h with a range of non-toxic concentrations of MC-RR or MC-LR. Minimal effects were observed after short term exposures (4h) to either MC variant. In contrast, dose dependent modulations of gene transcription levels were observed with MC-RR and MC-LR after 24h. The transcriptomic profiles induced by MC-RR were quite similar to those induced by MC-LR, suggestive of a largely common mechanism of toxicity. However, changes in total gene expression were more pronounced following exposure to MC-LR compared to MC-RR, as revealed by functional annotation. MC-LR affected two principal pathways, the oxidative stress response and cell cycle regulation, which did not elicit significant alteration following MC-RR exposure. This work is the first comparative description of the effects of MC-LR and MC-RR in a human intestinal cell model at the pangenomic scale. It has allowed us to propose differences in the mechanism of toxicity for MC-RR and MC-LR. These results illustrate that taking into account the toxicity of MC variants remains a key point for risk assessment.
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Affiliation(s)
- Perrine Zeller
- Anses, Fougères laboratory, Contaminant Toxicology Unit, La Haute Marche, BP 90203, 35302 Fougères Cedex, France
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Marie B, Huet H, Marie A, Djediat C, Puiseux-Dao S, Catherine A, Trinchet I, Edery M. Effects of a toxic cyanobacterial bloom (Planktothrix agardhii) on fish: insights from histopathological and quantitative proteomic assessments following the oral exposure of medaka fish (Oryzias latipes). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 114-115:39-48. [PMID: 22414781 DOI: 10.1016/j.aquatox.2012.02.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/07/2012] [Accepted: 02/11/2012] [Indexed: 05/31/2023]
Abstract
Cyanobacterial toxic blooms often occur in freshwater lakes and constitute a potential health risk to human populations, as well as to fish and other aquatic organisms. Microcystin-LR (the cyanotoxin most commonly detected in the freshwater environment) is a potent hepatotoxin, deregulating the kinase pathway by inhibiting phosphatases 1 and 2A. Although toxicological effects have been clearly linked to the in vitro exposure of fish to purified microcystins, cyanotoxins are produced by the cyanobacteria together with numerous other potentially toxic molecules, and their overall and specific implications for the health of fish have still not been clearly established and remain puzzlingly difficult to assess. The medaka fish (Oryzias latipes) was chosen as an in vitro model for studying the effects of a cyanobacterial bloom on liver protein contents using a gel free quantitative approach, iTRAQ, in addition to pathology examinations on histological preparations. Fish were gavaged with 5 μL cyanobacterial extracts (Planktothrix agardhii) from a natural bloom (La Grande Paroisse, France) containing 2.5 μg equiv. MC-LR. 2h after exposure, the fish were sacrificed and livers were collected for analysis. Histological observations indicate that hepatocytes present glycogen storage loss, and cellular damages, together with immunological localization of MCs. Using a proteomic approach, 304 proteins were identified in the fish livers, 147 of them with a high degree of identification confidence. Fifteen of these proteins were statistically significantly different from those of controls (gavaged with water only). Overall, these protein regulation discrepancies clearly indicate that oxidative stress and lipid regulation had occurred in the livers of the exposed medaka fish. In contrast to previous pure microcystin-LR gavage experiments, marked induction of vitellogenin 1 protein was observed for the first time with a cyanobacterial extract. This finding was confirmed by ELISA quantification of vitellogenin liver content, suggesting that the Planktothrix bloom extract had induced the occurrence of an endocrine-disrupting effect.
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Affiliation(s)
- Benjamin Marie
- UMR 7245 CNRS Molécules de Communication et Adaptation des Microorganismes, Équipe Cyanobactéries, Cyanotoxines et Environnement, Muséum National d'Histoire Naturelle, 12 Rue Buffon, F-75231 Paris Cedex 05, France
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Ufelmann H, Krüger T, Luckas B, Schrenk D. Human and rat hepatocyte toxicity and protein phosphatase 1 and 2A inhibitory activity of naturally occurring desmethyl-microcystins and nodularins. Toxicology 2012; 293:59-67. [DOI: 10.1016/j.tox.2011.12.011] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 12/16/2011] [Accepted: 12/25/2011] [Indexed: 10/14/2022]
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Ferranti P, Nasi A, Bruno M, Basile A, Serpe L, Gallo P. A peptidomic approach for monitoring and characterising peptide cyanotoxins produced in Italian lakes by matrix-assisted laser desorption/ionisation and quadrupole time-of-flight mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:1173-1183. [PMID: 21488115 DOI: 10.1002/rcm.4973] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In recent years, the occurrence of cyanobacterial blooms in eutrophic freshwaters has been described all over the world, including most European countries. Blooms of cyanobacteria may produce mixtures of toxic secondary metabolites, called cyanotoxins. Among these, the most studied are microcystins, a group of cyclic heptapeptides, because of their potent hepatotoxicity and activity as tumour promoters. Other peptide cyanotoxins have been described whose structure and toxicity have not been thoroughly studied. Herein we present a peptidomic approach aimed to characterise and quantify the peptide cyanotoxins produced in two Italian lakes, Averno and Albano. The procedure was based on matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry mass spectrometry (MALDI-TOF-MS) analysis for rapid detection and profiling of the peptide mixture complexity, combined with liquid chromatography/electrospray ionisation quadrupole time-of- flight tandem mass spectrometry (LC/ESI-Q-TOF-MS/MS) which provided unambiguous structural identification of the main compounds, as well as accurate quantitative analysis of microcystins. In the case of Lake Averno, a novel variant of microcystin-RR and two novel anabaenopeptin variants (Anabaenopeptins B(1) and Anabaenopeptin F(1)), presenting homoarginine in place of the commonly found arginine, were detected and characterised. In Lake Albano, the peculiar peptide patterns in different years were compared, as an example of the potentiality of the peptidomic approach for fast screening analysis, prior to fine structural analysis and determination of cyanotoxins, which included six novel aeruginosin variants. This approach allows for wide range monitoring of cyanobacteria blooms, and to collect data for evaluating possible health risks to consumers, through the panel of the compounds produced along different years.
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Affiliation(s)
- Pasquale Ferranti
- Department of Food Science, University of Naples Federico II, Portici (NA), Italy.
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Ostermaier V, Kurmayer R. Application of real-time PCR to estimate toxin production by the cyanobacterium Planktothrix sp. Appl Environ Microbiol 2010; 76:3495-502. [PMID: 20363794 PMCID: PMC2876456 DOI: 10.1128/aem.02771-09] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 03/24/2010] [Indexed: 11/20/2022] Open
Abstract
Quantitative real-time PCR methods are increasingly being applied for the enumeration of toxic cyanobacteria in the environment. However, to justify the use of real-time PCR quantification as a monitoring tool, significant correlations between genotype abundance and actual toxin concentrations are required. In the present study, we aimed to explain the concentrations of three structural variants of the hepatotoxin microcystin (MC) produced by the filamentous cyanobacterium Planktothrix sp., [Asp, butyric acid (Dhb)]-microcystin-RR (where RR means two arginines), [Asp, methyl-dehydro-alanine (Mdha)]-microcystin-RR, and [Asp, Dhb]-microcystin-homotyrosine-arginine (HtyR), by the abundance of the microcystin genotypes encoding their synthesis. Three genotypes of microcystin-producing cyanobacteria (denoted the Dhb, Mdha, and Hty genotypes) in 12 lakes of the Alps in Austria, Germany, and Switzerland from 2005 to 2007 were quantified by means of real-time PCR. Their absolute and relative abundances were related to the concentration of the microcystin structural variants in aliquots determined by high-performance liquid chromatography (HPLC). The total microcystin concentrations varied from 0 to 6.2 microg liter(-1) (mean +/- standard error [SE] of 0.6 +/- 0.1 microg liter(-1)) among the samples, in turn resulting in an average microcystin content in Planktothrix of 3.1 +/- 0.7 microg mm(-3) biovolume. Over a wide range of the population density (0.001 to 3.6 mm(3) liter(-1) Planktothrix biovolume), the Dhb genotype and [Asp, Dhb]-MC-RR were most abundant, while the Hty genotype and MC-HtyR were found to be in the lowest proportion only. In general, there was a significant linear relationship between the abundance/proportion of specific microcystin genotypes and the concentration/proportion of the respective microcystin structural variants on a logarithmic scale. We conclude that estimating the abundance of specific microcystin genotypes by quantitative real-time PCR is useful for predicting the concentration of microcystin variants in water.
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Affiliation(s)
- Veronika Ostermaier
- Institute for Limnology, Austrian Academy of Sciences, Mondseestrasse 9, A-5310 Mondsee, Austria
| | - Rainer Kurmayer
- Institute for Limnology, Austrian Academy of Sciences, Mondseestrasse 9, A-5310 Mondsee, Austria
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Deleuze C, De Pauw E, Quinton L. Selective reduction of C=C double bonds in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of microcystins. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2010; 16:91-99. [PMID: 20065523 DOI: 10.1255/ejms.1051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cyanobacteria are photosynthetic bacteria encountered in various aquatic environments. Some of them are able to produce powerful toxins called cyanotoxins. Among cyanotoxins, microcystins (MCs) constitute a group of closely related cyclic heptapeptides. Their sequences are made up of classical amino acids as well as post- translational modified ones. Interestingly, in vivo metabolism of microcystins seems to be greatly dependent on various minor structural differences and particularly those of the seventh amino acid, which can be either dehydroalanine (or a derivative), dehydroaminobutyric acid (or a derivative), serine or alanine. As a consequence, microcystins have been classified on the basis of the nature of this singular amino acid. A major difficulty in the classification of such toxins is that some of them share the same molecular masses and the same molecular formulas. Consequently, a simple mass measurement is not sufficient to determine the structure and the class of a toxin of interest. Heavy and expensive techniques are used to classify them, such as multi-dimensional nuclear magnetic resonance and amino acid analysis. In this work, a new matrix-assisted laser desorption/ionization time-of-flight method leading to an easy classification of MCs is proposed. The methodology relies on the reductive properties of the matrix 1,5-diaminonaphtalene (1,5-DAN) which appears to be able to selectively reduce the double carbon-carbon bond belonging to the seventh amino acid. Moreover, the yield of reduction seems to be influenced by the degree of substitution of this double bond, allowing a discrimination between dehydroalanine and dehydroaminobutyric acid. This selective reduction was confirmed by the study of three synthetic peptides by mass spectrometry and tandem mass spectrometry. According to these results, the use of reductive matrices seems to be promising in the study of microcystins and in their classification. More generally, 1,5-DAN allows the selective reduction of double carbon-carbon bonds. This property could also be employed in the characterization of others types of compound displaying double bonds (petrochemistry, metabolomics....).
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Affiliation(s)
- Christelle Deleuze
- GIGA-R: Laboratoire de Spectrométrie de Masse (L.S.M.), Département de Chimie, Université de Liège, Liège, Belgium
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Krüger T, Christian B, Luckas B. Development of an analytical method for the unambiguous structure elucidation of cyclic peptides with special appliance for hepatotoxic desmethylated microcystins. Toxicon 2009; 54:302-12. [PMID: 19397919 DOI: 10.1016/j.toxicon.2009.04.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 04/14/2009] [Accepted: 04/15/2009] [Indexed: 10/20/2022]
Abstract
The periodical occurrence of harmful algal blooms (HABs) in freshwater lakes requires the determination of potential cyanobacterial toxins, especially microcystins (MCs). On demand of an adequate risk assessment, the high diversity of these hepatotoxic cyclic heptapeptides implicates the need of an unambiguous detection of their specific structural variants. Therefore, LC-MS and LC-MS/MS methods are the approaches of choice for determination of MCs. In contrast, even tandem mass spectromic fragmentation patterns are not even sufficient in any kind of structural determination requirements, whereas NMR methods require very high amounts of MCs. In this study, we present a novel method for chromatographic separation of desmethylated microcystins (dm-MCs). Based on the isolation of the specific structural variants using semi-preparative HPLC, a method was developed for the structure elucidation of cyclic peptides with special appliance for the determination of dm-MCs via analysis of the specific amino acid composition after peptide hydrolysis followed by stereospecific detection of the amino acids and resulting keto acids. On the basis of this method it is demonstrated that dm-MC-RR with the structure [Dha(7)]MC-RR represented the major compound in the microcystin pattern of Microcystis aeruginosa bloom events in 2005 and 2006 in Lake Senftenberg, Germany.
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Affiliation(s)
- Thomas Krüger
- Department of Food Chemistry, Friedrich-Schiller-University of Jena, Institute of Nutrition, 07743 Jena, Germany.
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Dai R, Liu H, Qu J, Zhao X, Hou Y. Effects of amino acids on microcystin production of the Microcystis aeruginosa. JOURNAL OF HAZARDOUS MATERIALS 2009; 161:730-736. [PMID: 18486331 DOI: 10.1016/j.jhazmat.2008.04.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2007] [Revised: 03/14/2008] [Accepted: 04/05/2008] [Indexed: 05/26/2023]
Abstract
A Microcystis aeruginosa which produced high content of microcystin-LR (MC-LR) but no microcystin-RR (MC-RR) was isolated from Dianchi Lake in China. In the molecular structure of MC-LR, glutamic acid, aspartic acid, leucine, alanine and arginine are the constitutional components which are abundant in natural water. In this paper, effects of six amino acids at their natural concentrations on the growth of the M. aeruginosa and the microcystin (MC) production were studied in batch culture. M. aeruginosa could assimilate alanine, leucine and arginine as sole nitrogen sources for growth and MC production. However, glutamic acid, aspartic acid and lysine could not be assimilated quickly, although they could pass the cell membrane and enter into the cell rapidly. Our experiment demonstrated that the possible reason of such phenomenon was that different amino acids had different effects on the process of metabolism through the free dissolved amino acids within the cells.
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Affiliation(s)
- Ruihua Dai
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Hedman CJ, Krick WR, Karner Perkins DA, Harrahy EA, Sonzogni WC. New measurements of cyanobacterial toxins in natural waters using high performance liquid chromatography coupled to tandem mass spectrometry. JOURNAL OF ENVIRONMENTAL QUALITY 2008; 37:1817-1824. [PMID: 18689743 DOI: 10.2134/jeq2007.0368] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The presence and levels of the cyanobacterial toxins microcystin-LR, anatoxin-a, and cylindrospermopsin were measured in various Wisconsin waters where algal nuisance or bloom conditions were noted. Out of 74 samples analyzed, 36 had detectable levels of microcystin-LR (49%), and four had detectable levels of anatoxin-a (5%). Cylindrospermopsin, the toxin produced by Cylindrospermopsis (a warm water species that has been moving its range northward, including to Wisconsin), was not detected in the field samples tested. Concentrations of microcystin-LR ranged from 1.2 to 7600 microg L(-1). Anatoxin-a ranged from 0.68 to 1750 microg L(-1), which is the highest concentration reported from around the world. Cyanobacterial toxins, because of their high potency, deserve continued scrutiny by resource managers and public health officials responsible for recreational waters.
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Affiliation(s)
- Curtis J Hedman
- Wisconsin State Lab. of Hygiene, 2601 Agriculture Drive, Madison, WI, 53718, USA
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Dai R, Liu H, Qu J, Ru J, Hou Y. Cyanobacteria and their toxins in Guanting Reservoir of Beijing, China. JOURNAL OF HAZARDOUS MATERIALS 2008; 153:470-477. [PMID: 17919815 DOI: 10.1016/j.jhazmat.2007.08.078] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 08/28/2007] [Accepted: 08/28/2007] [Indexed: 05/25/2023]
Abstract
The present study investigated the cyanobacteria and one family of their toxins-microcystins (MCs) in Guanting Reservoir of Beijing, China. The dominant species in the cyanobacteria found in August and September of 2006 was Microcystis, which accounted 99% of total algal cells. The specific species of the Microcystis in the cyanobacteria included Microcystis ichthyobalbe, Microcystis novacekii, Microcystis botrys and Microcystis aeruginosa which had different ratios in different sites. The qualitative analysis by HPLC showed that two microcystins were contained in cyanobacteria and one microcystin was in water of the reservoir. The major microcystins were microcystin-RR (MC-RR) and microcystin-LR (MC-LR), but only MC-LR was detected in water. The quantitative analysis by HPLC indicated that the maximum concentrations of MC-RR and MC-LR contained in cyanobacteria were 0.74 and 0.41 mg/g dry weight, respectively. The maximum microcystin concentration in water was 1.15 microg/L and others were below 1 microg/L.
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Affiliation(s)
- Ruihua Dai
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
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Relationship of energy charge and toxin content of Microcystis aeruginosa in nitrogen-limited or phosphorous-limited cultures. Toxicon 2008; 51:649-58. [DOI: 10.1016/j.toxicon.2007.11.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 11/25/2007] [Accepted: 11/29/2007] [Indexed: 11/22/2022]
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