1
|
Wei N, Hu C, Dittmann E, Song L, Gan N. The biological functions of microcystins. WATER RESEARCH 2024; 262:122119. [PMID: 39059200 DOI: 10.1016/j.watres.2024.122119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 07/16/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024]
Abstract
Microcystins are potent hepatotoxins predominantly produced by bloom-forming freshwater cyanobacteria (e.g., Microcystis, Planktothrix, Dolichospermum). Microcystin biosynthesis involves large multienzyme complexes and tailoring enzymes encoded by the mcy gene cluster. Mutation, recombination, and deletion events have shaped the mcy gene cluster in the course of evolution, resulting in a large diversity of microcystin congeners and the natural coexistence of toxic and non-toxic strains. The biological functions of microcystins and their association with algal bloom formation have been extensively investigated over the past decades. This review synthesizes recent advances in decoding the biological role of microcystins in carbon/nitrogen metabolism, antioxidation, colony formation, and cell-to-cell communication. Microcystins appear to adopt multifunctional roles in cyanobacteria that reflect the adaptive plasticity of toxic cyanobacteria to changing environments.
Collapse
Affiliation(s)
- Nian Wei
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
| | - Chenlin Hu
- College of Pharmacy, University of Houston, Houston, TX 77204, USA
| | - Elke Dittmann
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Lirong Song
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Nanqin Gan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| |
Collapse
|
2
|
Stanković N, Jovanović B, Kokić IK, Piperac MS, Simeunović J, Jakimov D, Dimkić I, Milošević D. Toxic effects of a cyanobacterial strain on Chironomus riparius larvae in a multistress environment. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 253:106321. [PMID: 36308821 DOI: 10.1016/j.aquatox.2022.106321] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/23/2022] [Accepted: 10/01/2022] [Indexed: 05/06/2023]
Abstract
Cyanobacteria and their toxic metabolites present a global threat to water habitats, but their impact on aquatic organisms in a multistress environment has been poorly investigated. Here we present the results of a survey on the effects of the toxic cyanobacterial strain Trichormus variabilis (heterotypic synonym Anabaena variabilis), and its toxic metabolite, cyanotoxin microcystin-LR, on Chironomus riparius larvae in a multistress environment. An environmentally relevant concentration of microcystin-LR (0.01 mg/L) caused an increase in larvae mortality in an acute toxicity test, which became greater in the presence of environmental stressors (NO3-, NH4+, PO43- and Cd2+), pointing to an additive effect of these agents. Chronic exposure of C. riparius larvae to the microcystin-LR producing strain of T. variabilis in a multistress environment led to a reduction in the larval mass and hemoglobin concentration, and it induced DNA damage in larval somatic cells. The results revealed the additive effect of microcystin-LR in combination with all three tested stressors (NO3-, NH4+, PO43-), and the deleterious effect of chronic exposure of C. riparius larvae to the microcystin-LR producing T. variabilis in a multistress environment. However, the present study further emphasizes the importance of investigating interactions between stressors and cyanotoxins, and their effect on aquatic organisms.
Collapse
Affiliation(s)
- Nikola Stanković
- Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia.
| | - Boris Jovanović
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Ivana Kostić Kokić
- Department of Chemistry, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia
| | - Milica Stojković Piperac
- Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia
| | - Jelica Simeunović
- Department of Biology and Ecology, Faculty of Science, University of Novi Sad, Dr Zorana Đinđića 1, 21000 Novi Sad, Serbia
| | - Dimitar Jakimov
- Oncology Institute of Vojvodina, Faculty of Medicine, University of Novi Sad, Put Dr Goldmana 4, 21204 Sremska Kamenica, Serbia
| | - Ivica Dimkić
- Department of Biochemistry and Molecular Biology, University of Belgrade - Faculty of Biology, Studentski Trg 16, 11158 Belgrade, Serbia
| | - Djuradj Milošević
- Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia
| |
Collapse
|
3
|
Hellweger FL, Martin RM, Eigemann F, Smith DJ, Dick GJ, Wilhelm SW. Models predict planned phosphorus load reduction will make Lake Erie more toxic. Science 2022; 376:1001-1005. [PMID: 35617400 DOI: 10.1126/science.abm6791] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Harmful cyanobacteria are a global environmental problem, yet we lack actionable understanding of toxigenic versus nontoxigenic strain ecology and toxin production. We performed a large-scale meta-analysis including 103 papers and used it to develop a mechanistic, agent-based model of Microcystis growth and microcystin production. Simulations for Lake Erie suggest that the observed toxigenic-to-nontoxigenic strain succession during the 2014 Toledo drinking water crisis was controlled by different cellular oxidative stress mitigation strategies (protection by microcystin versus degradation by enzymes) and the different susceptibility of those mechanisms to nitrogen limitation. This model, as well as a simpler empirical one, predicts that the planned phosphorus load reduction will lower biomass but make nitrogen and light more available, which will increase toxin production, favor toxigenic cells, and increase toxin concentrations.
Collapse
Affiliation(s)
- Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - Robbie M Martin
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Falk Eigemann
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA.,Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| |
Collapse
|
4
|
Depth profiles of protein-bound microcystin in Küçükçekmece Lagoon. Toxicon 2021; 198:156-163. [PMID: 33992691 DOI: 10.1016/j.toxicon.2021.05.005] [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: 11/26/2020] [Revised: 04/17/2021] [Accepted: 05/10/2021] [Indexed: 11/20/2022]
Abstract
Microcystis is the most commonly found toxic cyanobacterial genus around the world and has a negative impact on the ecosystem. As a predominant producer of the potent hepatotoxin microcystin (MC), the genus causes outbreaks in freshwaters worldwide. Standard analytical methods that are used for the detection of microcystin variants can only measure the free form of microcystin in cells. Since microcystin was found as free and protein-bound forms in the cells, a significant proportion of microcystin is underestimated with analytical methods. The aim of the study was to measure protein-bound microcystins and determine the environmental factors that affect the binding of microcystin to proteins. Samples were taken at depths of surface, 1 m, 5 m, 10 m, 15 m, and 18 m in Küçükçekmece Lagoon to analyze depth profiles of two different microcystin forms from June to September 2012 at regular monthly intervals. Our findings suggest that the most important parameter affecting protein-bound microcystin at surface water is high light. Due to favorable environmental conditions such as temperature, light, and physicochemical parameters, the higher microcystin contents, both free and protein-bound MCs, were found in summer periods.
Collapse
|
5
|
|
6
|
Zhang Y, Whalen JK, Sauvé S. Phytotoxicity and bioconcentration of microcystins in agricultural plants: Meta-analysis and risk assessment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 272:115966. [PMID: 33168379 DOI: 10.1016/j.envpol.2020.115966] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/06/2020] [Accepted: 10/28/2020] [Indexed: 06/11/2023]
Abstract
Microcystins are cyanotoxins produced by many species of cyanobacteria. They are specific inhibitors of serine/threonine protein phosphatases and are phytotoxic to agricultural plants. This study used a formal meta-analysis to estimate the phytotoxicity and bioconcentration rates of agricultural plants exposed to microcystins, and the human health risk from consuming microcystin-contaminated plants. Among the 35 agricultural plants investigated, microcystins were most phytotoxic to durum wheat, corn, white mustard and garden cress. Leafy vegetables such as dill, parsley and cabbage could bioconcentrate ∼3 times more microcystins in their edible parts than other agricultural plants. Although the human health risk from ingesting microcystins could be greater for leafy vegetables than other agricultural plants, further work is needed to confirm bioconcentration of microcystins in realistic water-soil-plant environments. Still, we should avoid growing leafy vegetables, durum wheat and corn on agricultural land that is irrigated with microcystins-contaminated water and be attentive to the risk of microcystins contamination in the agricultural food supply.
Collapse
Affiliation(s)
- Yanyan Zhang
- McGill University, Department of Natural Resource Science, Macdonald Campus, 21,111 Lakeshore Road, Ste-Anne-de Bellevue, Quebec, Canada, H9X 3V9
| | - Joann K Whalen
- McGill University, Department of Natural Resource Science, Macdonald Campus, 21,111 Lakeshore Road, Ste-Anne-de Bellevue, Quebec, Canada, H9X 3V9.
| | - Sébastien Sauvé
- Université de Montréal, Department of Chemistry, C.P. 6128, Succursale Centre-Ville, Montreal, Quebec, Canada H3C 3J7
| |
Collapse
|
7
|
Malanga G, Giannuzzi L, Hernando M. The possible role of microcystin (D-Leu 1 MC-LR) as an antioxidant on Microcystis aeruginosa (Cyanophyceae). In vitro and in vivo evidence. Comp Biochem Physiol C Toxicol Pharmacol 2019; 225:108575. [PMID: 31326544 DOI: 10.1016/j.cbpc.2019.108575] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/18/2019] [Accepted: 07/16/2019] [Indexed: 11/19/2022]
Abstract
Microcystins constitute a serious threat to the quality of drinking water worldwide. However, the eco-physiological role of them is not completely known and it is suggested that toxins can play a role in the antioxidant protection. The objective of this study was to evaluate the microcystin antioxidant capacity in vitro by Electronic Paramagnetic Resonance, highly specific for the different reactive oxygen species and in vivo by 7 days exposure of Microcystis aeruginosa to high (29 °C) temperature in addition to a 26 °C control condition. An effective in vitro antioxidant activity was observed for [D-Leu1]MC-LR against hydrosoluble radicals. As far as we know, this is the first in vitro record of the role of MC as antioxidant. In addition, a significant increase in cellular biomass was observed under 26 °C in cultures with [D-Leu1]MC-LR supplementation in coincidence with a significant decrease of reactive species. For cultures at 29 °C, the antioxidant role of toxins was inconclusive probably due to the presence of different reactive species generated during the experiment. Thus, MC could scavenge certain reactive species associated with the antioxidant role of CAT or the OH content by SOD activity (not measured) and then CAT activity could be lower in the presence of MC. Reinforcing our hypothesis, the [D-Leu1]MC-LR consumption after 7 days was significantly higher in cells with [D-Leu1]MC-LR supplementation in both 26 °C and 29 °C.When the production of reactive species was controlled by the scavenger activity of antioxidants plus MC, cells avoided the potential oxidative damage and started with exponential growth.
Collapse
Affiliation(s)
- G Malanga
- CONICET-Universidad de Buenos Aires, Instituto de Bioquímica y Medicina Molecular (IBIMOL), Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Fisicoquímica, Buenos Aires, Argentina
| | - L Giannuzzi
- CONICET, Godoy Cruz 2290, Buenos Aires, Argentina; Área de Toxicología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina
| | - M Hernando
- Departamento Radiobiología, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina.
| |
Collapse
|
8
|
Ceballos-Laita L, Marcuello C, Lostao A, Calvo-Begueria L, Velazquez-Campoy A, Bes MT, Fillat MF, Peleato ML. Microcystin-LR Binds Iron, and Iron Promotes Self-Assembly. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4841-4850. [PMID: 28368104 DOI: 10.1021/acs.est.6b05939] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The microcystin-producing Microcystis aeruginosa PCC 7806 and its close strain, the nonproducing Microcystis aeruginosa PCC 7005, grow similarly in the presence of 17 μM iron. Under severe iron deficient conditions (0.05 μM), the toxigenic strain grows slightly less than in iron-replete conditions, while the nonproducing microcystin strain is not able to grow. Isothermal titration calorimetry performed at cyanobacterial cytosol or meaningful environmental pHs values shows a microcystin-LR dissociaton constant for Fe2+ and Fe3+ of 2.4 μM. Using atomic force microscopy, 40% of microcystin-LR dimers were observed, and the presence of iron promoted its oligomerization up to six units. Microcystin-LR binds also Mo6+, Cu2+, and Mn2+. Polymeric microcystin binding iron may be related with a toxic cell colony advantage, providing enhanced iron bioavailability and perhaps affecting the structure of the gelatinous sheath. Inside cells, with microcystin implicated in the fitness of the photosynthetic machinery under stress conditions, the toxin would be involved in avoiding metal-dependent Fenton reactions when photooxidation causes disassembly of the iron-rich photosystems. Additionally, it could be hypothesized that polymerization-depolymerization dynamics may be an additional signal that could trigger changes (for example, in the binding of microcystin to proteins).
Collapse
Affiliation(s)
- Laura Ceballos-Laita
- Institute for Biocomputation and Physics of Complex Systems (BIFI)-Joint Unit BIFI-IQFR (CSIC) , Aragón 50018, Spain
| | | | | | - Laura Calvo-Begueria
- Institute for Biocomputation and Physics of Complex Systems (BIFI)-Joint Unit BIFI-IQFR (CSIC) , Aragón 50018, Spain
| | - Adrián Velazquez-Campoy
- Institute for Biocomputation and Physics of Complex Systems (BIFI)-Joint Unit BIFI-IQFR (CSIC) , Aragón 50018, Spain
| | - María Teresa Bes
- Institute for Biocomputation and Physics of Complex Systems (BIFI)-Joint Unit BIFI-IQFR (CSIC) , Aragón 50018, Spain
| | - María F Fillat
- Institute for Biocomputation and Physics of Complex Systems (BIFI)-Joint Unit BIFI-IQFR (CSIC) , Aragón 50018, Spain
| | - María-Luisa Peleato
- Institute for Biocomputation and Physics of Complex Systems (BIFI)-Joint Unit BIFI-IQFR (CSIC) , Aragón 50018, Spain
| |
Collapse
|
9
|
Giannuzzi L, Krock B, Minaglia MCC, Rosso L, Houghton C, Sedan D, Malanga G, Espinosa M, Andrinolo D, Hernando M. Growth, toxin production, active oxygen species and catalase activity of Microcystis aeruginosa (Cyanophyceae) exposed to temperature stress. Comp Biochem Physiol C Toxicol Pharmacol 2016; 189:22-30. [PMID: 27449270 DOI: 10.1016/j.cbpc.2016.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/05/2016] [Accepted: 07/08/2016] [Indexed: 01/17/2023]
Abstract
Microcystis are known for their potential ability to synthesize toxins, mainly microcystins (MCs). In order to evaluate the effects of temperature on chlorophyll a (Chl a), growth, physiological responses and toxin production of a native Microcystis aeruginosa, we exposed the cells to low (23°C) and high (29°C) temperature in addition to a 26°C control treatment. Exponential growth rate was significantly higher at 29°C compared to 23°C and control, reaching 0.43, 0.32 and 0.33day(-)(1) respectively. In addition, there was a delay of the start of exponential growth at 23°C. However, the intracellular concentration of Chl a decreased significantly due to temperature change. A significant increase in intracellular ROS was observed in coincidence with the activation of enzymatic antioxidant catalase (CAT) during the first two days of exposure to 23° and 29°C in comparison to the control experiment, decreasing thereafter to nearly initial values. Five MCs were determined by LC-MS/MS analysis. In the experiments, the highest MC concentration, 205fg [Leu(1)] MC-LR.cell(-1) expressed as MC-LR equivalent was measured in the beginning of the experiment and subsequently declined to 160fg.cell(-1) on day 2 and 70fg.cell(-1) on day 4 in cells exposed to 29°C. The same trend was observed for all other MCs except for the least abundant MC-LR which showed a continuous increase during exposure time. Our results suggest a high ability of M. aeruginosa to perceive ROS and to rapidly initiate antioxidant defenses with a differential response on MC production.
Collapse
Affiliation(s)
- Leda Giannuzzi
- Área de Toxicología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina; CONICET, Buenos Aires, Argentina
| | - Bernd Krock
- Alfred Wegener Institute, Bremerhaven, Germany
| | - Melina Celeste Crettaz Minaglia
- Área de Toxicología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina; CONICET, Buenos Aires, Argentina
| | - Lorena Rosso
- Área de Toxicología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina
| | | | - Daniela Sedan
- Área de Toxicología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina; CONICET, Buenos Aires, Argentina
| | - Gabriela Malanga
- CONICET, Buenos Aires, Argentina; IBIMOL-FisicoQuímica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
| | - Mariela Espinosa
- Gerencia de Química, Comisión Nacional de Energía Atómica, Argentina
| | - Darío Andrinolo
- Área de Toxicología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina; CONICET, Buenos Aires, Argentina
| | - Marcelo Hernando
- Depto. Radiobiología, Comisión Nacional de Energía Atómica, Argentina.
| |
Collapse
|
10
|
Wei N, Hu L, Song L, Gan N. Microcystin-Bound Protein Patterns in Different Cultures of Microcystis aeruginosa and Field Samples. Toxins (Basel) 2016; 8:toxins8100293. [PMID: 27754336 PMCID: PMC5086653 DOI: 10.3390/toxins8100293] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/06/2016] [Accepted: 10/08/2016] [Indexed: 11/16/2022] Open
Abstract
Micocystin (MC) exists in Microcystis cells in two different forms, free and protein-bound. We examined the dynamic change in extracellular free MCs, intracellular free MCs and protein-bound MCs in both batch cultures and semi-continuous cultures, using high performance liquid chromatography and Western blot. The results showed that the free MC per cell remained constant, while the quantity of protein-bound MCs increased with the growth of Microcystis cells in both kinds of culture. Significant changes in the dominant MC-bound proteins occurred in the late exponential growth phase of batch cultures, while the dominant MC-bound proteins in semi-continuous cultures remained the same. In field samples collected at different months in Lake Taihu, the dominant MC-bound proteins were shown to be similar, but the amount of protein-bound MC varied and correlated with the intracellular MC content. We identified MC-bound proteins by two-dimensional electrophoresis immunoblots and mass spectrometry. The 60 kDa chaperonin GroEL was a prominent MC-bound protein. Three essential glycolytic enzymes and ATP synthase alpha subunit were also major targets of MC-binding, which might contribute to sustained growth in semi-continuous culture. Our results indicate that protein-bound MC may be important for sustaining growth and adaptation of Microcystis sp.
Collapse
Affiliation(s)
- Nian Wei
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lili Hu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lirong Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Nanqin Gan
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| |
Collapse
|
11
|
Geh EN, Ghosh D, McKell M, de la Cruz AA, Stelma G, Bernstein JA. Identification of Microcystis aeruginosa Peptides Responsible for Allergic Sensitization and Characterization of Functional Interactions between Cyanobacterial Toxins and Immunogenic Peptides. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:1159-66. [PMID: 25902363 PMCID: PMC4629744 DOI: 10.1289/ehp.1409065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 04/15/2015] [Indexed: 05/27/2023]
Abstract
BACKGROUND The cyanobacterium species Microcystis aeruginosa produces microcystin and an array of diverse metabolites believed responsible for their toxicity and/or immunogenicity. Previously, chronic rhinitis patients were demonstrated to elicit a specific IgE response to nontoxic strains of M. aeruginosa by skin-prick testing, indicating that cyanobacteria allergenicity resides in a non-toxin-producing component of the organism. OBJECTIVES We sought to identify and characterize M. aeruginosa peptide(s) responsible for allergic sensitization in susceptible individuals, and we investigated the functional interactions between cyanobacterial toxins and their coexpressed immunogenic peptides. METHODS Sera from patients and extracts from M. aeruginosa toxic [MC(+)] and nontoxic [MC(-)] strains were used to test IgE-specific reactivity by direct and indirect ELISAs; 2D gel electrophoresis, followed by immunoblots and mass spectrometry (MS), was performed to identify the relevant sensitizing peptides. Cytotoxicity and mediator release assays were performed using the MC(+) and MC(-) lysates. RESULTS We found specific IgE to be increased more in response to the MC(-) strain than the MC(+) strain. This response was inhibited by preincubation of MC(-) lysate with increasing concentrations of microcystin. MS revealed that phycocyanin and the core-membrane linker peptide are the responsible allergens, and MC(-) extracts containing these proteins induced β-hexosaminidase release in rat basophil leukemia cells. CONCLUSIONS Phycobiliprotein complexes in M. aeruginosa have been identified as the relevant sensitizing proteins. Our finding that allergenicity is inhibited in a dose-dependent manner by microcystin toxin suggests that further investigation is warranted to understand the interplay between immunogenicity and toxicity of cyanobacteria under diverse environmental conditions. CITATION Geh EN, Ghosh D, McKell M, de la Cruz AA, Stelma G, Bernstein JA. 2015. Identification of Microcystis aeruginosa peptides responsible for allergic sensitization and characterization of functional interactions between cyanobacterial toxins and immunogenic peptides. Environ Health Perspect 123:1159-1166; http://dx.doi.org/10.1289/ehp.1409065.
Collapse
Affiliation(s)
- Esmond N Geh
- Allergy Section, Division of Immunology Allergy, and Rheumatology, Department of Internal Medicine, and
| | | | | | | | | | | |
Collapse
|
12
|
El-Shehawy R, Gorokhova E, Fernández-Piñas F, del Campo FF. Global warming and hepatotoxin production by cyanobacteria: what can we learn from experiments? WATER RESEARCH 2012; 46:1420-9. [PMID: 22178305 DOI: 10.1016/j.watres.2011.11.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 11/02/2011] [Accepted: 11/07/2011] [Indexed: 05/08/2023]
Abstract
Global temperature is expected to rise throughout this century, and blooms of cyanobacteria in lakes and estuaries are predicted to increase with the current level of global warming. The potential environmental, economic and sanitation repercussions of these blooms have attracted considerable attention among the world's scientific communities, water management agencies and general public. Of particular concern is the worldwide occurrence of hepatotoxic cyanobacteria posing a serious threat to global public health. Here, we highlight plausible effects of global warming on physiological and molecular changes in these cyanobacteria and resulting effects on hepatotoxin production. We also emphasize the importance of understanding the natural biological function(s) of hepatotoxins, various mechanisms governing their synthesis, and climate-driven changes in food-web interactions, if we are to predict consequences of the current and projected levels of global warming for production and accumulation of hepatotoxins in aquatic ecosystems.
Collapse
|
13
|
Li D, Liu Z, Cui Y, Li W, Fang H, Li M, Kong Z. Toxicity of cyanobacterial bloom extracts from Taihu Lake on mouse, Mus musculus. ECOTOXICOLOGY (LONDON, ENGLAND) 2011; 20:1018-1025. [PMID: 21544556 DOI: 10.1007/s10646-011-0693-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/07/2011] [Indexed: 05/30/2023]
Abstract
The acute and sub-chronic toxicities of cyanobacterial extract from Taihu Lake (PR China) on mouse (Mus musculus) were investigated in this study via intraperitoneal (i.p.) injection. Increases in liver/body weight ratios and pathological changes in mouse liver showed adverse effects at the organ level. Images from transmission electron microscopy (TEM) indicated that abnormal membrane structure occurred and that the organelles were damaged severely in the cells of liver and testis. The high dose group received i.p. injection of 12 mg lyophilized algae cells/kg body weight. Malondialdehyde (MDA) levels increased significantly in the livers of this group, along with a significant decrease in catalase (CAT) activity. These results revealed the existence of obvious oxidative stress. Comet assay results also suggested a dose-dependent relationship between DNA damage in hepatocytes/testicular cells and the amount of bloom extract administered to the mice. There was a significant increase in DNA damage compared to the control group and the genotoxicity of the cyanobacterial bloom to testicular cells was higher than in hepatocytes.
Collapse
Affiliation(s)
- Dingsheng Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Campus, 163 Xianlin Avenue, Nanjing, 210046, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
14
|
Alexova R, Haynes PA, Ferrari BC, Neilan BA. Comparative protein expression in different strains of the bloom-forming cyanobacterium Microcystis aeruginosa. Mol Cell Proteomics 2011; 10:M110.003749. [PMID: 21610102 DOI: 10.1074/mcp.m110.003749] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Toxin production in algal blooms presents a significant problem for the water industry. Of particular concern is microcystin, a potent hepatotoxin produced by the unicellular freshwater species Microcystis aeruginosa. In this study, the proteomes of six toxic and nontoxic strains of M. aeruginosa were analyzed to gain further knowledge in elucidating the role of microcystin production in this microorganism. This represents the first comparative proteomic study in a cyanobacterial species. A large diversity in the protein expression profiles of each strain was observed, with a significant proportion of the identified proteins appearing to be strain-specific. In total, 475 proteins were identified reproducibly and of these, 82 comprised the core proteome of M. aeruginosa. The expression of several hypothetical and unknown proteins, including four possible operons was confirmed. Surprisingly, no proteins were found to be produced only by toxic or nontoxic strains. Quantitative proteome analysis using the label-free normalized spectrum abundance factor approach revealed nine proteins that were differentially expressed between toxic and nontoxic strains. These proteins participate in carbon-nitrogen metabolism and redox balance maintenance and point to an involvement of the global nitrogen regulator NtcA in toxicity. In addition, the switching of a previously inactive toxin-producing strain to microcystin synthesis is reported.
Collapse
Affiliation(s)
- Ralitza Alexova
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW 2052, Australia
| | | | | | | |
Collapse
|
15
|
Song C, Gao HW, Wu LL. Transmembrane transport of microcystin to Danio rerio zygotes: insights into the developmental toxicity of environmental contaminants. Toxicol Sci 2011; 122:395-405. [PMID: 21602189 DOI: 10.1093/toxsci/kfr131] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Microcystins (MCs) produced by cyanobacteria and their continuing "blooms" are a worldwide problem owing to the toxicity of microcystin-LR (MC-LR) to plants and animals. In the present study, we investigated membrane transport of MC-LR and its toxic effects on zebrafish embryos using fragmentation of embryos, scanning electron microscope (SEM), fluorescence microscopy, and toxic exposure tests. At a concentration < 0.04 mmol/l, MC-LR was predominantly adsorbed on outer membrane surface of embryos according to Langmuir isotherm. The absorption characteristics of MC-LR within the range from 0.05 to 0.4 mmol/l conformed to Freundlich isotherm model. At concentrations > 0.50 mmol/l MC-LR directly entered the cytoplasm via partition. Thinning and disruption of membranes was confirmed using SEM and fluorescence morphological observations. Exposure to different concentrations of MC-LR resulted in differences in membrane transport and toxicity characteristics. At low concentrations, more than 75% of the adsorbed MC-LR accumulated on the outer membrane surface and resulted in axial malformation, tail curving, and tail twisting. Increasing the concentration of MC-LR to between 0.05 and 0.4 mmol/l improved membrane transport and it was evident in cytoplasm of embryos, resulting in serious pericardial edema, hatching gland edema, hemagglutination, hemorrhage, and vacuolization. At > 0.50 mmol/l, more than 70% of the adsorbed MC-LR entered the cytoplasm and this was lethal to the embryos. The current research outlines a new method and mechanism for the transmembrane transport of large molecular weight organic compounds and could be important for studies concerning molecular toxicology.
Collapse
Affiliation(s)
- Chao Song
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | | | | |
Collapse
|
16
|
Zilliges Y, Kehr JC, Meissner S, Ishida K, Mikkat S, Hagemann M, Kaplan A, Börner T, Dittmann E. The cyanobacterial hepatotoxin microcystin binds to proteins and increases the fitness of microcystis under oxidative stress conditions. PLoS One 2011; 6:e17615. [PMID: 21445264 PMCID: PMC3060824 DOI: 10.1371/journal.pone.0017615] [Citation(s) in RCA: 279] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 02/01/2011] [Indexed: 11/18/2022] Open
Abstract
Microcystins are cyanobacterial toxins that represent a serious threat to drinking water and recreational lakes worldwide. Here, we show that microcystin fulfils an important function within cells of its natural producer Microcystis. The microcystin deficient mutant ΔmcyB showed significant changes in the accumulation of proteins, including several enzymes of the Calvin cycle, phycobiliproteins and two NADPH-dependent reductases. We have discovered that microcystin binds to a number of these proteins in vivo and that the binding is strongly enhanced under high light and oxidative stress conditions. The nature of this binding was studied using extracts of a microcystin-deficient mutant in vitro. The data obtained provided clear evidence for a covalent interaction of the toxin with cysteine residues of proteins. A detailed investigation of one of the binding partners, the large subunit of RubisCO showed a lower susceptibility to proteases in the presence of microcystin in the wild type. Finally, the mutant defective in microcystin production exhibited a clearly increased sensitivity under high light conditions and after hydrogen peroxide treatment. Taken together, our data suggest a protein-modulating role for microcystin within the producing cell, which represents a new addition to the catalogue of functions that have been discussed for microbial secondary metabolites.
Collapse
Affiliation(s)
- Yvonne Zilliges
- Institute of Biology, Department of Molecular Ecology, Humboldt University, Berlin, Germany
| | - Jan-Christoph Kehr
- Institute of Biochemistry and Biology, Department of Microbiology Potsdam-Golm, University of Potsdam, Potsdam, Germany
| | - Sven Meissner
- Institute of Biochemistry and Biology, Department of Microbiology Potsdam-Golm, University of Potsdam, Potsdam, Germany
| | - Keishi Ishida
- Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany
| | - Stefan Mikkat
- Medical Faculty, Core Facility Proteome Analysis, University of Rostock, Rostock, Germany
| | - Martin Hagemann
- Institute of Biology, Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Thomas Börner
- Humboldt University, Institute of Biology, Department of Genetics, Berlin, Germany
| | - Elke Dittmann
- Institute of Biochemistry and Biology, Department of Microbiology Potsdam-Golm, University of Potsdam, Potsdam, Germany
| |
Collapse
|
17
|
Shi Y, Guo C, Sun Y, Liu Z, Xu F, Zhang Y, Wen Z, Li Z. Interaction between DNA and Microcystin-LR Studied by Spectra Analysis and Atomic Force Microscopy. Biomacromolecules 2011; 12:797-803. [DOI: 10.1021/bm101414w] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan Shi
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, People’s Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
| | - Cunlan Guo
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, People’s Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
| | - Yujing Sun
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, People’s Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
| | - Zhelin Liu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, People’s Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
| | - Fugang Xu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, People’s Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
| | - Yue Zhang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, People’s Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
| | - Zhiwei Wen
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, People’s Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
| | - Zhuang Li
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, People’s Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing, 100039, People’s Republic of China
| |
Collapse
|