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Vaz R, Valpradinhos B, Frasco MF, Sales MGF. Emerging Optical Materials in Sensing and Discovery of Bioactive Compounds. SENSORS (BASEL, SWITZERLAND) 2021; 21:5784. [PMID: 34502675 PMCID: PMC8434157 DOI: 10.3390/s21175784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/20/2021] [Accepted: 08/22/2021] [Indexed: 11/16/2022]
Abstract
Optical biosensors are used in numerous applications and analytical fields. Advances in these sensor platforms offer high sensitivity, selectivity, miniaturization, and real-time analysis, among many other advantages. Research into bioactive natural products serves both to protect against potentially dangerous toxic compounds and to promote pharmacological innovation in drug discovery, as these compounds have unique chemical compositions that may be characterized by greater safety and efficacy. However, conventional methods for detecting these biomolecules have drawbacks, as they are time-consuming and expensive. As an alternative, optical biosensors offer a faster, simpler, and less expensive means of detecting various biomolecules of clinical interest. In this review, an overview of recent developments in optical biosensors for the detection and monitoring of aquatic biotoxins to prevent public health risks is first provided. In addition, the advantages and applicability of these biosensors in the field of drug discovery, including high-throughput screening, are discussed. The contribution of the investigated technological advances in the timely and sensitive detection of biotoxins while deciphering the pathways to discover bioactive compounds with great health-promoting prospects is envisaged to meet the increasing demands of healthcare systems.
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Affiliation(s)
- Raquel Vaz
- BioMark@UC, Faculty of Sciences and Technology, University of Coimbra, 3030-790 Coimbra, Portugal; (R.V.); (M.G.F.S.)
- CEB—Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal;
| | - Beatriz Valpradinhos
- CEB—Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal;
- BioMark@ISEP, School of Engineering, Polytechnic Institute of Porto, 4249-015 Porto, Portugal
| | - Manuela F. Frasco
- BioMark@UC, Faculty of Sciences and Technology, University of Coimbra, 3030-790 Coimbra, Portugal; (R.V.); (M.G.F.S.)
- CEB—Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal;
- BioMark@ISEP, School of Engineering, Polytechnic Institute of Porto, 4249-015 Porto, Portugal
| | - Maria Goreti F. Sales
- BioMark@UC, Faculty of Sciences and Technology, University of Coimbra, 3030-790 Coimbra, Portugal; (R.V.); (M.G.F.S.)
- CEB—Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal;
- BioMark@ISEP, School of Engineering, Polytechnic Institute of Porto, 4249-015 Porto, Portugal
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2
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Review on Cyanobacterial Studies in Portugal: Current Impacts and Research Needs. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11104355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cyanobacteria have long been associated with harmful effects on humans, animals and aquatic biota. Cyanotoxins are their most toxic metabolite. This review summarizes the current research, impacts and future needs in cyanobacterial studies undertaken in Portugal, the southernmost country of Europe, and with a recent multiplication of cyanotoxicity due to climate change events. Microcystins are still the most prevalent, studied and the only regulated cyanotoxins in Portuguese freshwater systems much like most European countries. With the development of some tools, particularly in molecular studies, the recent discovery of cylindrospermopsins, anatoxins and saxitoxins, both genes and toxins, in North and Center ecosystems of our country highlight current impacts that overall communities are facing with increased risks of exposure and uptake to cyanotoxins. Research needs encompass the expansion of studies at all aspects due to the uprising of these cyanotoxins and reinforces the urgent need of increasing the frequency of surveillance to achieve tangible effects of cyanotoxins in Portugal to ultimately implement regulations on cylindrospermopsins, anatoxins and saxitoxins worldwide.
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Díez-Quijada L, Puerto M, Gutiérrez-Praena D, Llana-Ruiz-Cabello M, Jos A, Cameán AM. Microcystin-RR: Occurrence, content in water and food and toxicological studies. A review. ENVIRONMENTAL RESEARCH 2019; 168:467-489. [PMID: 30399604 DOI: 10.1016/j.envres.2018.07.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/09/2018] [Accepted: 07/09/2018] [Indexed: 06/08/2023]
Abstract
Microcystins (MCs) are hepatotoxins, produced by various species of cyanobacteria, whose occurrence is increasing worldwide owing to climate change and anthropogenic activities. More than 100 variants have been reported, and among them MC-LR is the most extensively studied, but there are other MC congeners that deserve to be investigated. The need for data to characterize the toxicological profile of MC variants other than MC-LR has been identified in order to improve risk assessment in humans and wildlife. Accordingly, the aim of this study was to evaluate the information available in the scientific literature dealing with MC-RR, as this congener is the second most common cyanotoxin in the environment. The review focuses on aspects such as occurrence in water and food, and toxicity studies both in vitro and in vivo. It reveals that, although MC-RR is a real hazard with a high exposure potential in some countries, little is known yet about its specific toxicological properties that differ from those of MC-LR, and important aspects such as genotoxicity and chronic effects have not yet been sufficiently addressed.
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Affiliation(s)
- Leticia Díez-Quijada
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain
| | - María Puerto
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain.
| | - Daniel Gutiérrez-Praena
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain
| | - María Llana-Ruiz-Cabello
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain
| | - Angeles Jos
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain
| | - Ana M Cameán
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain
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Díez-Quijada L, Prieto AI, Guzmán-Guillén R, Jos A, Cameán AM. Occurrence and toxicity of microcystin congeners other than MC-LR and MC-RR: A review. Food Chem Toxicol 2018; 125:106-132. [PMID: 30597222 DOI: 10.1016/j.fct.2018.12.042] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/29/2018] [Accepted: 12/25/2018] [Indexed: 12/11/2022]
Abstract
The occurrence of cyanobacterial toxins is being increasingly reported. This is a reason for concern as they can induce toxic effects both in humans and in the environment. Among them, microcystins (MCs) are the best described and most diverse group of cyanobacterial toxins, and MC-LR and MC-RR are the congeners most widely investigated. However, the number of MC variants has also increased in recent years. Some of these minority variants have been shown to have a different toxicokinetic and toxicodynamic profile, but research focused on them is still limited. Moreover, in some water bodies these minority variants can be the predominant toxins. Nonetheless, MC-LR is the only one used for risk evaluation purposes at present. In order to contribute to more realistic risk assessments in the future, the aim of this review was to compile the available information in the scientific literature regarding the occurrence and concentration of minority MCs in water and food samples, and their toxic effects. The data retrieved demonstrate the congener-specific toxicity of MCs, as well as many data gaps in relation to analytical or mechanistic aspects, among others. Therefore, further research is needed to improve the toxicological characterization of these toxins and the exposure scenarios.
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Affiliation(s)
- Leticia Díez-Quijada
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain
| | - Ana I Prieto
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain
| | - Remedios Guzmán-Guillén
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain
| | - Angeles Jos
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain.
| | - Ana M Cameán
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain
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Manubolu M, Lee J, Riedl KM, Kua ZX, Collart LP, Ludsin SA. Optimization of extraction methods for quantification of microcystin-LR and microcystin-RR in fish, vegetable, and soil matrices using UPLC-MS/MS. HARMFUL ALGAE 2018; 76:47-57. [PMID: 29887204 PMCID: PMC7282678 DOI: 10.1016/j.hal.2018.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/22/2018] [Accepted: 04/30/2018] [Indexed: 05/30/2023]
Abstract
Human-driven environmental change has increased the occurrence of harmful cyanobacteria blooms in aquatic ecosystems. Concomitantly, exposure to microcystin (MC), a cyanobacterial toxin that can accumulate in animals, edible plants, and agricultural soils, has become a growing public health concern. For accurate estimation of health risks and timely monitoring, availability of reliable detection methods is imperative. Nonetheless, quantitative analysis of MCs in many types of biological and environmental samples has proven challenging because matrix interferences can hinder sample preparation and extraction procedures, leading to poor MC recovery. Herein, controlled experiments were conducted to enhance the use of ultra-performance liquid-chromatography tandem-mass spectrometry (UPLC-MS/MS) to recover MC-LR and MC-RR at a range of concentrations in seafood (fish), vegetables (lettuce), and environmental (soil) matrices. Although these experiments offer insight into detailed technical aspects of the MC homogenization and extraction process (i.e., sonication duration and centrifugation speed during homogenization; elution solvent to use during the final extraction), they centered on identifying the best (1) solvent system to use during homogenization (2-3 tested per matrix) and (2) single-phase extraction (SPE) column type (3 tested) to use for the final extraction. The best procedure consisted of the following, regardless of sample type: centrifugation speed = 4200 × g; elution volume = 8 mL; elution solvent = 80% methanol; and SPE column type = hydrophilic-lipophilic balance (HLB), with carbon also being satisfactory for fish. For sonication, 2 min, 5 min, and 10 min were optimal for fish, lettuce, and soil matrices, respectively. Using the recommended HLB column, the solvent systems that led to the highest recovery of MCs were methanol:water:butanol for fish, methanol:water for lettuce, and EDTA-Na4P2O7 for soils. Given that the recommended procedures resulted in average MC-LR and MC-RR recoveries that ranged 93 to 98%, their adoption for the preparation of samples with complex matrices before UPLC-MS/MS analysis is encouraged.
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Affiliation(s)
- Manjunath Manubolu
- Aquatic Ecology Laboratory, Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH, USA; Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, OH, USA.
| | - Jiyoung Lee
- Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, OH, USA; Department of Food Science and Technology, The Ohio State University, Columbus, OH, USA
| | - Kenneth M Riedl
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, USA
| | - Zi Xun Kua
- Aquatic Ecology Laboratory, Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH, USA
| | - Lindsay P Collart
- Aquatic Ecology Laboratory, Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH, USA; Department of Microbiology, Oregon State University, Corvallis, OR, USA
| | - Stuart A Ludsin
- Aquatic Ecology Laboratory, Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH, USA
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Toxicological and biochemical responses of the earthworm Eisenia fetida to cyanobacteria toxins. Sci Rep 2017; 7:15954. [PMID: 29162925 PMCID: PMC5698456 DOI: 10.1038/s41598-017-16267-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/09/2017] [Indexed: 02/02/2023] Open
Abstract
Irrigation with eutrophic water containing cyanobacteria toxins poses a potential risk to soil animals. To evaluate ecotoxicological effect of microcystins (MCs) on earthworms, filter paper acute toxicity test, avoidance test and a 14-d artificial soil test were carried out. No acute toxicity was found in the filter paper test, and earthworms showed no avoidance response to MCs exposure. In the artificial soil test, Eisenia fetida were allowed to grow in presence or absence of MCs (0, 1, 10, 100, 1000 μg kg−1 of soil) for 1, 7, and 14 d. Results showed that MCs could bioaccumulated in earthworm. A stimulatory effect on catalase and glutathione oxidase activities induced by MCs was found on day 1, and both of them were significantly inhibited at 100 and 1000 μg kg−1 on days 14. The superoxide dismutase activity was relatively insensitive. Significant increase of malondialdehyde content and decrease of neutral red retention time were observed at 100 and 1000 μg kg−1 on days 7 and 14. Our results suggest that MCs induces oxidative stress on earthworms, which leads to disruption of the antioxidant system and lipid peroxidation, as well as alterations in lysosomal membrane stability.
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Menezes C, Churro C, Dias E. Risk Levels of Toxic Cyanobacteria in Portuguese Recreational Freshwaters. Toxins (Basel) 2017; 9:toxins9100327. [PMID: 29057822 PMCID: PMC5666374 DOI: 10.3390/toxins9100327] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 11/16/2022] Open
Abstract
Portuguese freshwater reservoirs are important socio-economic resources, namely for recreational use. National legislation concerning bathing waters does not include mandatory levels or guidelines for cyanobacteria and cyanotoxins. This is an issue of concern since cyanotoxin-based evidence is insufficient to change the law, and the collection of scientific evidence has been hampered by the lack of regulatory levels for cyanotoxins in bathing waters. In this work, we evaluate the profile of cyanobacteria and microcystins (MC) in eight freshwater reservoirs from the center of Portugal, used for bathing/recreation, in order to determine the risk levels concerning toxic cyanobacteria occurrence. Three of the reservoirs did not pose a risk of MC contamination. However, two reservoirs presented a high risk in 7% of the samples according to the World Health Organization (WHO) guidelines for MC in bathing waters (above 20 µg/L). In the remaining three reservoirs, the risk concerning microcystins occurrence was low. However, they exhibited recurrent blooms and persistent contamination with MC up to 4 µg/L. Thus, the risk of exposure to MC and potential acute and/or chronic health outcomes should not be disregarded in these reservoirs. These results contribute to characterize the cyanobacterial blooms profile and to map the risk of toxic cyanobacteria and microcystins occurrence in Portuguese inland waters.
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Affiliation(s)
- Carina Menezes
- Department of Environmental Health, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisboa, Portugal.
| | - Catarina Churro
- Department of Environmental Health, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisboa, Portugal.
| | - Elsa Dias
- Department of Environmental Health, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisboa, Portugal.
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Umehara A, Takahashi T, Komorita T, Orita R, Choi JW, Takenaka R, Mabuchi R, Park HD, Tsutsumi H. Widespread dispersal and bio-accumulation of toxic microcystins in benthic marine ecosystems. CHEMOSPHERE 2017; 167:492-500. [PMID: 27756043 DOI: 10.1016/j.chemosphere.2016.10.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/31/2016] [Accepted: 10/10/2016] [Indexed: 05/21/2023]
Abstract
Freshwater cyanobacteria produce toxic microcystins (MCs), which travel from freshwater areas into the sea. The MCs produced by cyanobacteria in a freshwater reservoir were discharged frequently into the adjacent Isahaya Bay, remained in the surface sediments, and then accumulated in various macrobenthic animals on the seafloor. The MCs were transported further outside of Isahaya Bay (Ariake Bay), and the median values of the MC contents in the sediments were in the same levels in both bays, while their temporal variations were also similar during the study period. Therefore, the fluctuations of the MC contents in the surface sediments were physically controlled by the timing of the discharge from the reservoir. The MC contents in polychaetes and oysters collected in Isahaya Bay increased markedly during winter. The median values of the carbon-based MC contents in the sediments, primary consumers, and secondary consumers in the bay were 87, 160, and 250 ngMC gC-1, respectively. These results demonstrated bio-accumulation at lower trophic levels in benthic marine ecosystems. An understanding of the processes occurring between sediments and macrobenthic animals is important for clarifying MC dynamics in ecosystems.
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Affiliation(s)
- Akira Umehara
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan.
| | - Tohru Takahashi
- Department of Medical Technology, Kumamoto Health Science University, 325 Izumi-machi, Kumamoto, 861-5598, Japan
| | - Tomohiro Komorita
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan
| | - Ryo Orita
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan
| | - Jin-Woo Choi
- Korea Institute of Ocean Science and Technology, 41 Jangmok 1-gil, Jangmok-Myon, Geoji, 656-834, Republic of Korea
| | - Risa Takenaka
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan
| | - Rie Mabuchi
- Department of Environmental Science, Faculty of Science, Shinshu University, Matsumoto, 390-8621, Japan
| | - Ho-Dong Park
- Department of Environmental Science, Faculty of Science, Shinshu University, Matsumoto, 390-8621, Japan
| | - Hiroaki Tsutsumi
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan
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Peng Q, Nunes LM, Greenfield BK, Dang F, Zhong H. Are Chinese consumers at risk due to exposure to metals in crayfish? A bioaccessibility-adjusted probabilistic risk assessment. ENVIRONMENT INTERNATIONAL 2016; 88:261-268. [PMID: 26773397 DOI: 10.1016/j.envint.2015.12.035] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/23/2015] [Accepted: 12/29/2015] [Indexed: 05/06/2023]
Abstract
Freshwater crayfish, the world's third largest crustacean species, has been reported to accumulate high levels of metals, while the current knowledge of potential risk associated with crayfish consumption lags behind that of finfish. We provide the first estimate of human health risk associated with crayfish (Procambarus clarkii) consumption in China, the world's largest producer and consumer of crayfish. We performed Monte Carlo Simulation on a standard risk model parameterized with local data on metal concentrations, bioaccessibility (φ), crayfish consumption rate, and consumer body mass. Bioaccessibility of metals in crayfish was found to be variable (68-95%) and metal-specific, suggesting a potential influence of metal bioaccessibility on effective metal intake. However, sensitivity analysis suggested risk of metals via crayfish consumption was predominantly explained by consumption rate (explaining >92% of total risk estimate variability), rather than metals concentration, bioaccessibility, or body mass. Mean metal concentrations (As, Cd, Cu, Ni, Pb, Se and Zn) in surveyed crayfish samples from 12 provinces in China conformed to national safety standards. However, risk calculation of φ-modified hazard quotient (HQ) and hazard index (HI) suggested that crayfish metals may pose a health risk for very high rate consumers, with a HI of over 24 for the highest rate consumers. Additionally, the φ-modified increased lifetime risk (ILTR) for carcinogenic effects due to the presence of As was above the acceptable level (10(-5)) for both the median (ILTR=2.5×10(-5)) and 90th percentile (ILTR=1.8×10(-4)), highlighting the relatively high risk of As in crayfish. Our results suggest a need to consider crayfish when assessing human dietary exposure to metals and associated health risks, especially for high crayfish-consuming populations, such as in China, USA and Sweden.
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Affiliation(s)
- Qian Peng
- Nanjing University, School of Environment, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China
| | - Luís M Nunes
- University of Algarve, Civil Engineering Research and Innovation for Sustainability Center, Faro, Portugal
| | - Ben K Greenfield
- Environmental Health Sciences Division, School of Public Health, University of California, Berkeley, USA
| | - Fei Dang
- State Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province, China
| | - Huan Zhong
- Nanjing University, School of Environment, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China; Environmental and Life Sciences Program, Trent University, Peterborough, Ontario, Canada.
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Singh S, Asthana RK. Assessment of microcystin concentration in carp and catfish: a case study from Lakshmikund pond, Varanasi, India. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2014; 92:687-692. [PMID: 24771133 DOI: 10.1007/s00128-014-1277-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 04/08/2014] [Indexed: 06/03/2023]
Abstract
The present study was conducted to analyse microcystin concentrations in Lakshmikund pond, Varanasi, India, as well as in carp and catfish of the pond. The concentrations of microcystin were found well above the WHO guidelines (1 µg/L) both for the dissolved and particulate fractions of bloom samples. The microcystin concentrations in different organs of carp and catfish were in the following sequence; liver > gut > kidney > gall bladder > gills > muscles and gut > liver > kidney > gall bladder > gills > muscles, respectively. The bioaccumulation of microcystin in carp and catfish was negatively correlated with body weight, and showed species specificity. The higher bioaccumulation of microcystin in muscles of catfish (>tenfold) over carp indicates a possible threat to human beings on consumption of catfish. Therefore, to avoid animal and human intoxication, routine analyses of microcystin in pond water as well as fishes are strongly recommended.
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Affiliation(s)
- Shweta Singh
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India
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11
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Amrani A, Nasri H, Azzouz A, Kadi Y, Bouaïcha N. Variation in cyanobacterial hepatotoxin (microcystin) content of water samples and two species of fishes collected from a shallow lake in Algeria. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2014; 66:379-389. [PMID: 24445842 DOI: 10.1007/s00244-013-9993-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/30/2013] [Indexed: 06/03/2023]
Abstract
Microcystins (MCs) produced from cyanobacteria can accumulate in freshwater fish tissues. In this study, variations in these toxins content were examined monthly in water samples and two species of fish in Lake Oubeira, Algeria, from April 2010 to March 2011. During the study period, MCs were analyzed using protein phosphatase type 2A (PP2A) inhibition assay. In lake water, total (dissolved and intracellular toxins) MC concentrations by PP2A ranged from 0.028 to 13.4 μg equivalent MC-LR/l, with a peak in September 2010. MC-LR was the dominant variant (90 % of the total) in water samples, followed by MC-YR and MC-(H4)YR. The highest MC concentration in the omnivorous common carp (Cyprinus carpio) was found in the order intestine > hepatopancreas > muscle; however, in the carnivorous European eel (Anguilla anguilla) the order was liver > intestine > muscle. Highest MC concentrations in the intestine tissue of the common carp were found between August and November 2010 where high MC concentrations were detected in water samples, whereas high levels of MCs in the liver of the European eel were found later between January and February 2011. During the entire period of study, the World Health Organization (WHO) lifetime limit for tolerable daily intake was exceeded only in common carp muscle.
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Affiliation(s)
- Amina Amrani
- Laboratoire Biodiversité et Pollution des Écosystèmes, Institut des Sciences de la Nature et de la Vie, Université d'El Tarf, 36 000, El Tarf, Algérie
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12
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Figueiredo D, Castro B, Pereira M, Correia A. Bacterioplankton community composition in Portuguese water bodies under a severe summer drought. COMMUNITY ECOL 2012. [DOI: 10.1556/comec.13.2012.2.8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Seasonal dynamics of Microcystis spp. and their toxigenicity as assessed by qPCR in a temperate reservoir. Mar Drugs 2011; 9:1715-1730. [PMID: 22072994 PMCID: PMC3210603 DOI: 10.3390/md9101715] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 09/15/2011] [Accepted: 09/26/2011] [Indexed: 01/22/2023] Open
Abstract
Blooms of toxic cyanobacteria are becoming increasingly frequent, mainly due to water quality degradation. This work applied qPCR as a tool for early warning of microcystin(MC)-producer cyanobacteria and risk assessment of water supplies. Specific marker genes for cyanobacteria, Microcystis and MC-producing Microcystis, were quantified to determine the genotypic composition of the natural Microcystis population. Correlations between limnological parameters, pH, water temperature, dissolved oxygen and conductivity and MC concentrations as well as Microcystis abundance were assessed. A negative significant correlation was observed between toxic (with mcy genes) to non-toxic (without mcy genes) genotypes ratio and the overall Microcystis density. The highest proportions of toxic Microcystis genotypes were found 4-6 weeks before and 8-10 weeks after the peak of the bloom, with the lowest being observed at its peak. These results suggest positive selection of non-toxic genotypes under favorable environmental growth conditions. Significant positive correlations could be found between quantity of toxic genotypes and MC concentration, suggesting that the method applied can be useful to predict potential MC toxicity risk. No significant correlation was found between the limnological parameters measured and MC concentrations or toxic genotypes proportions indicating that other abiotic and biotic factors should be governing MC production and toxic genotypes dynamics. The qPCR method here applied is useful to rapidly estimate the potential toxicity of environmental samples and so, it may contribute to the more efficient management of water use in eutrophic systems.
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Moreno IM, Herrador MÁ, Atencio L, Puerto M, González AG, Cameán AM. Differentiation between microcystin contaminated and uncontaminated fish by determination of unconjugated MCs using an ELISA anti-Adda test based on receiver-operating characteristic curves threshold values: application to Tinca tinca from natural ponds. ENVIRONMENTAL TOXICOLOGY 2011; 26:45-56. [PMID: 19645030 DOI: 10.1002/tox.20528] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The aim of this study was to evaluate whether the enzyme-linked immunosorbent assay (ELISA) anti-Adda technique could be used to monitor free microcystins (MCs) in biological samples from fish naturally exposed to toxic cyanobacteria by using receiver operating characteristic (ROC) curve software to establish an optimal cut-off value for MCs. The cut-off value determined by ROC curve analysis in tench (Tinca tinca) exposed to MCs under laboratory conditions by ROC curve analysis was 5.90-μg MCs/kg tissue dry weight (d.w.) with a sensitivity of 93.3%. This value was applied in fish samples from natural ponds (Extremadura, Spain) in order to asses its potential MCs bioaccumulation by classifying samples as either true positive (TP), false positive (FP), true negative (TN), or false negative (FN). In this work, it has been demonstrated that toxic cyanobacteria, mainly Microcystis aeruginosa, Aphanizomenon issatchenkoi, and Anabaena spiroides, were present in two of these ponds, Barruecos de Abajo (BDown) and Barruecos de Arriba (BUp). The MCs levels were detected in waters from both ponds with an anti-MC-LR ELISA immunoassay and were of similar values (between 3.8-6.5-μg MC-LR equivalent/L in BDown pond and 4.8-6.0-μg MC-LR equivalent/L in BUp). The MCs cut-off values were applied in livers from fish collected from these two ponds using the ELISA anti-Adda technique. A total of 83% of samples from BDown pond and only 42% from BUp were TP with values of free MCs higher than 8.8-μg MCs/kg tissue (d.w.).
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Affiliation(s)
- Isabel María Moreno
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, C/ Profesor García González 2, 41012 Sevilla, Spain.
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15
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Miller MA, Kudela RM, Mekebri A, Crane D, Oates SC, Tinker MT, Staedler M, Miller WA, Toy-Choutka S, Dominik C, Hardin D, Langlois G, Murray M, Ward K, Jessup DA. Evidence for a novel marine harmful algal bloom: cyanotoxin (microcystin) transfer from land to sea otters. PLoS One 2010; 5:e12576. [PMID: 20844747 PMCID: PMC2936937 DOI: 10.1371/journal.pone.0012576] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 08/02/2010] [Indexed: 12/05/2022] Open
Abstract
"Super-blooms" of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb) were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussels and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels) and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine "harmful algal bloom" in the Pacific coastal environment; that of hepatotoxic shellfish poisoning (HSP), suggesting that animals and humans are at risk from microcystin poisoning when consuming shellfish harvested at the land-sea interface.
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Affiliation(s)
- Melissa A Miller
- Marine Wildlife Veterinary Care and Research Center, California Department of Fish and Game, Office of Spill Prevention and Response, Santa Cruz, California, United States of America.
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16
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Rajabi H, Filizadeh Y, Soltani M, Fotokian M. The Use of Barley Straw for Controlling of Cyanobacteria Under Field Application. ACTA ACUST UNITED AC 2010. [DOI: 10.3923/jfas.2010.394.401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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17
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Smith JL, Schulz KL, Zimba PV, Boyer GL. Possible mechanism for the foodweb transfer of covalently bound microcystins. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2010; 73:757-61. [PMID: 20071028 DOI: 10.1016/j.ecoenv.2009.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 11/30/2009] [Accepted: 12/01/2009] [Indexed: 05/21/2023]
Abstract
Microcystins (MCs) are cyanobacterial toxins that inhibit protein phosphatases 1 and 2A (PP1, PP2A) within an animal through both reversible and covalent interactions. Only MCs that have accumulated in animal tissue in reversible interactions are currently considered when estimating risk to higher trophic levels and humans through food web exposure. However, the majority of MCs is likely covalently bound to target proteins in tissues and these MCs are not quantified or included in these assessments. These covalently bound MCs may be made bioavailable in the digestive system of a consumer through the digestion of their attached protein phosphatase. Three common digestive enzymes, pepsin, chymotrypsin, and trypsin, did not digest cyclic MC-LR and MC-LY, but were very active against a control peptide with typical linkages and standard amino acids in "L" conformation, supporting the possibility for MC-peptide formation during gut passage. To test if digestion products could be biologically active in the consumer, four predicted MC-peptides were synthesized and assayed for activity against PP1 by the protein phosphatase inhibition assay (PPIA). All four MC-peptides were active against PP1 and comparably half (58%) as inhibitory as the parent toxin. This in vitro study demonstrated that MCs covalently bound to proteins may represent a reservoir of potential toxicity for consumers.
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Affiliation(s)
- Juliette L Smith
- Department of Environmental and Forest Biology, State University of New York, Syracuse, College of Environmental Science and Forestry, Syracuse, NY 13210, USA
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18
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Nyakairu GWA, Nagawa CB, Mbabazi J. Assessment of cyanobacteria toxins in freshwater fish: a case study of Murchison Bay (Lake Victoria) and Lake Mburo, Uganda. Toxicon 2009; 55:939-46. [PMID: 19646467 DOI: 10.1016/j.toxicon.2009.07.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 06/16/2009] [Accepted: 07/22/2009] [Indexed: 11/17/2022]
Abstract
There is little information on the distribution of microcystins (MCs) in Oreochromis niloticus (ON) and Lates niloticus (LN) obtained from L. Mburo and Murchison Bay of L. Victoria. These fishes are harvested and sold both for local human consumption and for export. The presence of MC-RR, MC-LR and MC-YR in different organs (gut, muscle and liver) was determined using Liquid Chromatography coupled with a Mass Spectrometry Detector (LC/MS/MS). The total MCs in ON gut, muscle and liver were 1312.08, 208.65 and 73.10 ng g(-1) from L. Mburo and 1479.24, 9.65 and 48.07 ng g(-1) from Murchison Bay, respectively, while for LN from Murchison Bay they were 27.78, 1.86 and 3.74 ng g(-1). Generally, in both lakes, MC-RR was the most dominant followed by MC-YR and MC-LR, respectively. Gut showed a high MC content, followed by liver and muscle, in that order. The presence of MCs in muscle indicated possible fish contamination, which implied that it was possible to transfer the toxins to humans who are at the end of the food chain. This poses a risk to them since the MCs are heat stable. The local authorities should warn the public of the risk of possible poisoning by eating the contaminated fish.
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Chen J, Zhang D, Xie P, Wang Q, Ma Z. Simultaneous determination of microcystin contaminations in various vertebrates (fish, turtle, duck and water bird) from a large eutrophic Chinese lake, Lake Taihu, with toxic Microcystis blooms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2009; 407:3317-22. [PMID: 19249079 DOI: 10.1016/j.scitotenv.2009.02.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Revised: 01/31/2009] [Accepted: 02/02/2009] [Indexed: 05/22/2023]
Abstract
This is the first to conduct simultaneous determination of microcystin (MC) contaminations in multi-groups of vertebrates (fish, turtle, duck and water bird) from Lake Taihu with Microcystis blooms. MCs (-RR, -YR, -LR) in Microcystis scum was 328 microg g(-1) DW. MCs reached 235 microg g(-1) DW in intestinal contents of phytoplanktivorous silver carp, but never exceeded 0.1 microg g(-1) DW in intestinal contents of other animals. The highest MC content in liver of fish was in Carassius auratus (150 ng g(-1) DW), followed by silver carp and Culter ilishaeformis, whereas the lowest was in common carp (3 ng g(-1) DW). In livers of turtle, duck and water bird, MC content ranged from 18 to 30 ng g(-1) DW. High MC level was found in the gonad, egg yolk and egg white of Nycticorax nycticorax and Anas platyrhynchos, suggesting the potential effect of MCs on water bird and duck embryos. High MC contents were identified for the first time in the spleens of N. nycticorax and A. platyrhynchos (6.850 and 9.462 ng g(-1) DW, respectively), indicating a different organotropism of MCs in birds. Lakes with deaths of turtles or water birds in the literatures had a considerably higher MC content in both cyanobacteria and wildlife than Lake Taihu, indicating that toxicity of cyanobacteria may determine accumulation level of MCs and consequently fates of aquatic wildlife.
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Affiliation(s)
- Jun Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
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20
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Barrington DJ, Ghadouani A. Application of hydrogen peroxide for the removal of toxic cyanobacteria and other phytoplankton from wastewater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:8916-8921. [PMID: 19192818 DOI: 10.1021/es801717y] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Phytoplankton blooms containing elevated levels of cyanobacteria are common in wastewatertreatment plants. Microcystis aeruginosa, the most common freshwater cyanobacterial species, produces the hepatotoxin microcystin, which is a threat to human and environmental health. Blooms also affect the viability of treating and reusing water and cause problems when detritus accumulates in pipe and pumping delivery infrastructure. We proposed the application of hydrogen peroxide (H2O2) to induce cyanobacterial cell death. Spectral fingerprinting of phytoplankton into four groups (cyanobacteria, chlorophyta, diatoms, and cryptophyta) allowed for determination of equivalent chlorophyll-a (chl-a) concentrations contributed by photosynthetic pigments, an indicative measure of the photosynthetic activity of each phytoplankton group. This was used to establish the effect of H2O2 addition on phytoplankton in wastewater samples. The lowest H2O2 dose that caused statistically significant exponential decay of phytoplankton groups was approximately 3.0 x 10(-3) g H2O2/microg phytoplankton chl-a. At this dose, cyanobacteria and total phytoplankton exhibited a half-life of 2.3 and 4.5 h, respectively. Cyanobacteria decayed at a rate approximately twice that of chlorophyta and diatoms, and the combined chl-a of all phytoplankton groups decreased to negligible levels within 48 h of H202 application.
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Affiliation(s)
- Dani J Barrington
- Aquatic Ecology and Ecosystem Studies, School of Environmental Systems Engineering, The University of Western Australia, 35 Stirling Highway, M015, Crawley, Western Australia 6009, Australia.
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21
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Baptista MS, Vasconcelos MT. Cyanobacteria Metal Interactions: Requirements, Toxicity, and Ecological Implications. Crit Rev Microbiol 2008; 32:127-37. [PMID: 16893750 DOI: 10.1080/10408410600822934] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The environmental health-related relevance of cyanobacteria is primarily related to their ability to produce a wide range of toxins, which are known to be hazardous to many organisms, including human beings. The occurrence of cyanobacterial blooms has been related to eutrophic surface water. In the bloom-forming process the levels of phosphorus and nitrogen have been well documented but information regarding concentrations of other chemicals (inorganic, organo-metallic, and organic) is still incipient. Several contaminants, like trace metals, elicit a variety of acute and chronic toxicity effects, but cyanobacteria also have the capability to accumulate, detoxify, or metabolize such substances, to some extent. The role of cyanobacterial exudates has been proved a means of both nutrient acquisition and detoxification. In addition, cyanobacteria are effective biological metal sorbents, representing an important sink for metals in aquatic environment. Understanding the fundamental physicochemical mechanisms of trace metal bio-uptake by cyanobacteria in natural systems is a step towards identifying under what conditions cyanobacterial growth is favored and to ascertain the mechanisms by which blooms (and toxin production) are triggered. In this review the cyanobacterial interactions with metals will be discussed, focusing on freshwater systems.
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Affiliation(s)
- Mafalda S Baptista
- Chemistry Department, Faculty of Sciences, University of Porto, Porto, Portugal.
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22
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Abstract
Blue-green algae are found in lakes, ponds, rivers and brackish waters throughout the world. In case of excessive growth such as bloom formation, these bacteria can produce inherent toxins in quantities causing toxicity in mammals, including humans. These cyanotoxins include cyclic peptides and alkaloids. Among the cyclic peptides are the microcystins and the nodularins. The alkaloids include anatoxin-a, anatoxin-a(S), cylindrospermopsin, saxitoxins (STXs), aplysiatoxins and lyngbyatoxin. Both biological and chemical methods are used to determine cyanotoxins. Bioassays and biochemical assays are nonspecific, so they can only be used as screening methods. HPLC has some good prospects. For the subsequent detection of these toxins different detectors may be used, ranging from simple UV-spectrometry via fluorescence detection to various types of MS. The main problem in the determination of cyanobacterial toxins is the lack of reference materials of all relevant toxins. In general, toxicity data on cyanotoxins are rather scarce. A majority of toxicity data are known to be of microcystin-LR. For nodularins, data from a few animal studies are available. For the alkaloids, limited toxicity data exist for anatoxin-a, cylindrospermopsin and STX. Risk assessment for acute exposure could be relevant for some types of exposure. Nevertheless, no acute reference doses have formally been derived thus far. For STX(s), many countries have established tolerance levels in bivalves, but these limits were set in view of STX(s) as biotoxins, accumulating in marine shellfish. Official regulations for other cyanotoxins have not been established, although some (provisional) guideline values have been derived for microcystins in drinking water by WHO and several countries.
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Affiliation(s)
- Marian E van Apeldoorn
- Centre for Substances and Integrated Risk Assessment, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
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23
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Stone D, Bress W. Addressing public health risks for cyanobacteria in recreational freshwaters: the Oregon and Vermont framework. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2007; 3:137-143. [PMID: 17283602 DOI: 10.1002/ieam.5630030112] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Toxigenic cyanobacteria, commonly known as blue green algae, are an emerging public health issue. The toxins produced by cyanobacteria have been detected across the United States in marine, freshwater and estuarine systems and associated with adverse health outcomes. The intent of this paper is to focus on how to address risk in a recreational freshwater scenario when toxigenic cyanobacteria are present. Several challenges exist for monitoring, assessing and posting water bodies and advising the public when toxigenic cyanobacteria are present. These include addressing different recreational activities that are associated with varying levels of risk, the dynamic temporal and spatial aspects of blooms, data gaps in toxicological information and the lack of training and resources for adequate surveillance. Without uniform federal guidance, numerous states have taken public health action for cyanobacteria with different criteria. Vermont and Oregon independently developed a tiered decision-making framework to reduce risk to recreational users when toxigenic cyanobacteria are present. This framework is based on a combination of qualitative and quantitative information.
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Affiliation(s)
- David Stone
- Oregon State Public Health, Environmental Toxicology, 800 NE Oregon Street #608, Portland, Oregon 97219, USA.
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24
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Smith JL, Haney JF. Foodweb transfer, accumulation, and depuration of microcystins, a cyanobacterial toxin, in pumpkinseed sunfish (Lepomis gibbosus). Toxicon 2006; 48:580-9. [PMID: 16928388 DOI: 10.1016/j.toxicon.2006.07.009] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Revised: 07/05/2006] [Accepted: 07/06/2006] [Indexed: 10/24/2022]
Abstract
Zooplankton accumulate microcystins (MC), a potent cyanobacteria toxin, and therefore may act as vectors of the toxin up the aquatic food web; however this transfer has not yet been quantified. In addition there is a lack of information regarding fish's ability to metabolize MC when administered a low dose over a longer period of time. We monitored MC concentrations in three levels of an aquatic food web: phytoplankton, zooplankton, and sunfish (Lepomis gibbosus). Bosmina appeared to be both a major accumulator of MC in zooplankton and the major vector of MC to sunfish. In an accumulation experiment, sunfish were brought into the laboratory and fed MC-rich zooplankton pellets (50 ng MC kg(-1)d(-1)) for 9 days. Zooplankton directly transferred MC to sunfish, resulting in liver and muscle tissue accumulation. However, after 6 days of accumulation fish significantly decreased concentrations in their liver and muscle tissue, indicating the induction of a detoxification and excretion pathway. Sunfish retained MC in their liver and muscle tissue, showing no significant changes in toxin concentration over 2 weeks of fasted depuration.
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Affiliation(s)
- Juliette L Smith
- Faculty of Environmental and Forest Biology, State University of New York, Syracuse, College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210, USA.
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25
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Wood SA, Briggs LR, Sprosen J, Ruck JG, Wear RG, Holland PT, Bloxham M. Changes in concentrations of microcystins in rainbow trout, freshwater mussels, and cyanobacteria in Lakes Rotoiti and Rotoehu. ENVIRONMENTAL TOXICOLOGY 2006; 21:205-22. [PMID: 16646016 DOI: 10.1002/tox.20174] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Microcystin concentrations in cyanobacteria and their accumulation in rainbow trout (Oncorhynchus mykiss) and freshwater mussels (Hyridella menziesi) in Lakes Rotoiti and Rotoehu (New Zealand) were investigated. Hatchery rainbow trout were added to an enclosure in Lake Rotoiti where concentrations of microcystins in the phytoplankton and cyanobacterial cell concentrations could be closely monitored. Rainbow trout that were free to roam in the entire area of each lake were also included in the study. Freshwater mussels were suspended subsurface in cages in the enclosure. Phytoplankton samples, rainbow trout liver and muscle tissue, and the tissues of mussels were analyzed for microcystins using the ADDA-ELISA method, and selected samples were analyzed using LC-MS. A maximum concentration of microcystins in the phytoplankton samples of 760 microg L(-1) was recorded in Te Weta Bay, Lake Rotoiti, in March 2004. ELISA results confirmed microcystin immunoreactivity in rainbow trout liver and muscle tissues and in freshwater mussels. The microcystin congeners LR, YR, RR, AR, FR, LA, and WR were detected by LC-MS in caged freshwater mussels in Lake Rotoiti but were not detected in either muscle or liver tissue of rainbow trout. The daily tolerable intake limit of microcystins for human consumption recommended by the World Health Organisation is 0.04 microg kg(-1) day(-1). Modeling was carried out for the human intake of microcystin compounds from rainbow trout muscle tissue, and the potential health risks were estimated, assuming the ADDA-ELISA was determining compounds of toxicity equivalent to microcystin-LR.
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Affiliation(s)
- S A Wood
- Cawthron Institute, Private Bag 2, Nelson, New Zealand.
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Dittmann E, Wiegand C. Cyanobacterial toxins - occurrence, biosynthesis and impact on human affairs. Mol Nutr Food Res 2006; 50:7-17. [PMID: 16304634 DOI: 10.1002/mnfr.200500162] [Citation(s) in RCA: 283] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mass developments of cyanobacteria ("blue-green algae") in lakes and brackish waters have repeatedly led to serious concerns due to their frequent association with toxins. Among these are the widespread hepatotoxins microcystin (MC) and nodularin (NOD). Here, we give an overview about the ecostrategies of the diverse toxin-producing species and about the genes and enzymes that are involved in the biosynthesis of the cyclic peptides. We further summarize current knowledge about toxicological mechanisms of MC and NOD, including protein phosphatase inhibition, oxidative stress and their tumor-promoting capabilities. One biotransformation pathway for MC is described. Mechanisms of cyanobacterial neurotoxins (anatoxin-a, homanatoxin-a, and anatoxin-a(s)) are briefly explained. We highlight selected cases of human fatalities related to the toxins. A special focus is given to evident cases of contamination of food supplements with cyanobacterial toxins, and to the necessary precautions.
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Affiliation(s)
- Elke Dittmann
- Humboldt University, Institute of Biology, Berlin, Germany.
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Xie L, Xie P, Guo L, Li L, Miyabara Y, Park HD. Organ distribution and bioaccumulation of microcystins in freshwater fish at different trophic levels from the eutrophic Lake Chaohu, China. ENVIRONMENTAL TOXICOLOGY 2005; 20:293-300. [PMID: 15892067 DOI: 10.1002/tox.20120] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
This article reports the organ distribution and bioaccumulation of hepatotoxic microcystins (MCs) in freshwater fishes at different trophic levels from the large, shallow, eutrophic Lake Chaohu in September 2003, when there were heavy surface blooms of toxic cyanobacteria. Among all fish, intestines and blood had the highest average content of MC-RR + MC-LR (22.0 and 14.5 microg g(-1) DW, respectively), followed by liver, bile, and kidney (7.77, 6.32, and 5.81 microg g(-1) DW, respectively), whereas muscle had the least (1.81 microg g(-1) DW). MC content in muscle was highest in carnivorous fish (Culter ilishaeformis, 2.22 microg g(-1) DW) and omnivorous fish (Carassius auratus, 1.96 microg g(-1) DW) and was lowest in phytoplanktivorous fish (Hypophthalmichthys molitrix, 1.65 microg g(-1) DW) and herbivorous fish (Parabramis pekinensis 0.660 microg g(-1) DW). However, the amount of MC in the gut of H. molitrix (137 microg g(-1) DW) was more than 20 times that in the other fish (<6.50 microg g(-1) DW). The MCs showed a tendency to accumulate up the food chain, and piscivorous fish at the top of the food chain were at high risk of exposure to MCs in Lake Chaohu. Our study is the first to report MC concentrations in the bile and blood of wild fish. One hundred grams of fish muscle would contain 2.64-49.7 microg of MC-LR equivalent, or about 1.3-25 times the recommended tolerable daily intake of MC-LR by humans, indicating that fish are already severely contaminated by MCs and that the local authorities should warn the public of the risk of poisoning by eating the contaminated fish.
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Affiliation(s)
- Liqiang Xie
- Department of Environmental Science, Faculty of Science, Shinshu University, Matsumoto 390-8621, Japan
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28
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Ibelings BW, Bruning K, de Jonge J, Wolfstein K, Pires LMD, Postma J, Burger T. Distribution of microcystins in a lake foodweb: no evidence for biomagnification. MICROBIAL ECOLOGY 2005; 49:487-500. [PMID: 16052377 DOI: 10.1007/s00248-004-0014-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2004] [Accepted: 06/24/2004] [Indexed: 05/03/2023]
Abstract
Microcystins, toxins produced by cyanobacteria, may play a role in fish kills, although their specific contribution remains unclear. A better understanding of the eco-toxicological effects of microcystins is hampered by a lack of analyses at different trophic levels in lake foodwebs. We present 3 years of monitoring data, and directly compare the transfer of microcystin in the foodweb starting with the uptake of (toxic) cyanobacteria by two different filter feeders: the cladoceran Daphnia galeata and the zebra mussel Dreissena polymorpha. Furthermore foodwebs are compared in years in which the colonial cyanobacterium Microcystis aeruginosa or the filamentous cyanobacterium Planktothrix agardhii dominated; there are implications in terms of the types and amount of microcystins produced and in the ingestion of cyanobacteria. Microcystin concentrations in the seston commonly reached levels where harmful effects on zooplankton are to be expected. Likewise, concentrations in zooplankton reached levels where intoxication of fish is likely. The food chain starting with Dreissena (consumed by roach and diving ducks) remained relatively free from microcystins. Liver damage, typical for exposure to microcystins, was observed in a large fraction of the populations of different fish species, although no relation with the amount of microcystin could be established. Microcystin levels were especially high in the livers of planktivorous fish, mainly smelt. This puts piscivorous birds at risk. We found no evidence for biomagnification of microcystins. Concentrations in filter feeders were always much below those in the seston, and yet vectorial transport to higher trophic levels took place. Concentrations of microcystin in smelt liver exceeded those in the diet of these fish, but it is incorrect to compare levels in a selected organ to those in a whole organism (zooplankton). The discussion focuses on the implications of detoxication and covalent binding of microcystin for the transfer of the toxin in the foodweb. It seems likely that microcystins are one, but not the sole, factor involved in fish kills during blooms of cyanobacteria.
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Affiliation(s)
- B W Ibelings
- Institute for Inland Water Management and Waste Water Treatment (RIZA), Lelystad, The Netherlands.
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29
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Dietrich D, Hoeger S. Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): a reasonable or misguided approach? Toxicol Appl Pharmacol 2005; 203:273-89. [PMID: 15737681 DOI: 10.1016/j.taap.2004.09.005] [Citation(s) in RCA: 222] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Accepted: 09/08/2004] [Indexed: 10/26/2022]
Abstract
This article reviews current scientific knowledge on the toxicity and carcinogenicity of microcystins and compares this to the guidance values proposed for microcystins in water by the World Health Organization, and for blue-green algal food supplements by the Oregon State Department of Health. The basis of the risk assessment underlying these guidance values is viewed as being critical due to overt deficiencies in the data used for its generation: (i) use of one microcystin congener only (microcystin-LR), while the other presently known nearly 80 congeners are largely disregarded, (ii) new knowledge regarding potential neuro and renal toxicity of microcystins in humans and (iii) the inadequacies of assessing realistic microcystin exposures in humans and especially in children via blue-green algal food supplements. In reiterating the state-of-the-art toxicology database on microcystins and in the light of new data on the high degree of toxin contamination of algal food supplements, this review clearly demonstrates the need for improved kinetic data of microcystins in humans and for discussion concerning uncertainty factors, which may result in a lowering of the present guidance values and an increased routine control of water bodies and food supplements for toxin contamination. Similar to the approach taken previously by authorities for dioxin or PCB risk assessment, the use of a toxin equivalent approach to the risk assessment of microcystins is proposed.
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Affiliation(s)
- Daniel Dietrich
- University of Konstanz, Environmental Toxicology, 78457 Konstanz, Germany
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Hoeger SJ, Hitzfeld BC, Dietrich DR. Occurrence and elimination of cyanobacterial toxins in drinking water treatment plants. Toxicol Appl Pharmacol 2005; 203:231-42. [PMID: 15737677 DOI: 10.1016/j.taap.2004.04.015] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Accepted: 04/27/2004] [Indexed: 11/24/2022]
Abstract
Toxin-producing cyanobacteria (blue-green algae) are abundant in surface waters used as drinking water resources. The toxicity of one group of these toxins, the microcystins, and their presence in surface waters used for drinking water production has prompted the World Health Organization (WHO) to publish a provisional guideline value of 1.0 mug microcystin (MC)-LR/l drinking water. To verify the efficiency of two different water treatment systems with respect to reduction of cyanobacterial toxins, the concentrations of MC in water samples from surface waters and their associated water treatment plants in Switzerland and Germany were investigated. Toxin concentrations in samples from drinking water treatment plants ranged from below 1.0 microg MC-LR equiv./l to more than 8.0 microg/l in raw water and were distinctly below 1.0 microg/l after treatment. In addition, data to the worldwide occurrence of cyanobacteria in raw and final water of water works and the corresponding guidelines for cyanobacterial toxins in drinking water worldwide are summarized.
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Affiliation(s)
- Stefan J Hoeger
- Environmental Toxicology, University of Konstanz, Konstanz, Germany
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Zurawell RW, Chen H, Burke JM, Prepas EE. Hepatotoxic cyanobacteria: a review of the biological importance of microcystins in freshwater environments. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2005; 8:1-37. [PMID: 15762553 DOI: 10.1080/10937400590889412] [Citation(s) in RCA: 303] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Cyanobacteria possess many adaptations to develop population maxima or "blooms" in lakes and reservoirs. A potential consequence of freshwater blooms of many cyanobacterial species is the production of potent toxins, including the cyclic hepatotoxins, microcystins (MCs). Approximately 70 MC variants have been isolated. Their toxicity to humans and other animals is well studied, because of public health concerns. This review focuses instead on the production and degradation of MCs in freshwater environments and their effects on aquatic organisms. Genetic research has revealed the existence of MC-related genes, yet the expression of these genes seems to be regulated by complex mechanisms and is influenced by environmental factors. In natural water bodies, the species composition of cyanobacterial communities and the ratio of toxic to nontoxic species and strains are largely responsible for total toxin production. Cyanobacteria play vital roles in aquatic food webs, yet production, accumulation, and toxicity patterns of MCs within aquatic food webs remain obscure.
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Affiliation(s)
- Ronald W Zurawell
- Department of Biological Sciences, Biological Sciences Building, University of Alberta, Edmonton, Alberta, Canada
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Grovel O, Pouchus YF, Verbist JF. Accumulation of gliotoxin, a cytotoxic mycotoxin from Aspergillus fumigatus, in blue mussel (Mytilus edulis). Toxicon 2003; 42:297-300. [PMID: 14559081 DOI: 10.1016/s0041-0101(03)00146-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A strain of Aspergillus fumigatus has been isolated from sediments of a mussel bed. When cultured in hyper saline conditions (with sea-water), it produces a cytotoxic and immunosuppressive toxin, gliotoxin, which is excreted in an exudate. In order to know if this toxin could represent a risk for shellfish consumers, an experiment of bioaccumulation of gliotoxin in mussel has been carried out. After 6 days of contamination, toxin was accumulated in the meat of the mussels, at a level up to 2.9 microg/mg of extract weight, with a mode of contamination different to the classical digestive process described for a majority of marine toxins, but similar to the contamination mode of domoic acid.
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Affiliation(s)
- Olivier Grovel
- Faculté de Pharmacie, Groupe Substances Marines à Activité Biologique, Université de Nantes, ISOMer, BP 53508, Nantes 01 44035, France
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Yokoyama A, Park HD. Depuration kinetics and persistence of the cyanobacterial toxin microcystin-LR in the freshwater bivalve Unio douglasiae. ENVIRONMENTAL TOXICOLOGY 2003; 18:61-67. [PMID: 12539145 DOI: 10.1002/tox.10102] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We carried out uptake and depuration experiments in the laboratory to investigate the effects of temperature (15 degrees C and 25 degrees C) on the depuration kinetics and persistence of a cyanobacterial toxin, microcystin-LR (MCYST-LR), in a freshwater bivalve, Unio douglasiae. Bivalves were fed toxic Microcystis cells in the 15-day uptake experiment and nontoxic diatoms in the following 15-day depuration experiment. Each bivalve's hepatopancreas was lyophilized and extracted with a butanol:methanol:water solution for analysis of MCYST-LR by high-performance liquid chromatography. The toxin in the organ accumulated rapidly after the beginning of the uptake experiment and reached approximately steady-state conditions on day 5 at concentrations of 130 +/- 11 microg g(-1) dry weight at 15 degrees C and 250 +/- 40 microg g(-1) at 25 degrees C. In the depuration experiments MCYST-LR was eliminated asymptotically from the tissue. The values of the depuration rate constant (k(d)), calculated with a first-order one-compartment model, were found to be 0.142 +/- 0.044 day(-1) at 15 degrees C and 0.226 +/- 0.046 day(-1) at 25 degrees C. The depuration Q(10) value from 15 degrees C to 25 degrees C equaled 1.6. This study was the first to reveal the kinetics of depuration for MCYST-LR in a bivalve. The results show that MCYST-LR may be eliminated slowly in autumn and winter and persist in the tissue until spring. Thus, in terms of toxicokinetics, the risk to people of being poisoned by bivalves would increase if toxic blooms occur in autumn.
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Affiliation(s)
- Atsushi Yokoyama
- Department of Environmental Sciences, Faculty of Science, Shinshu University, Matsumoto 390-8621, Japan
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Oudra B, Loudiki M, Vasconcelos V, Sabour B, Sbiyyaa B, Oufdou K, Mezrioul N. Detection and quantification of microcystins from cyanobacteria strains isolated from reservoirs and ponds in Morocco. ENVIRONMENTAL TOXICOLOGY 2002; 17:32-39. [PMID: 11847972 DOI: 10.1002/tox.10029] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In Morocco, the occurrence of toxic cyanobacteria blooms is confirmed in some water bodies used for recreational and/or as drinking water reservoirs. According to WHO recommendations, the establishment of a monitoring program for microcystins is a necessity. This paper presents toxicological studies of 19 toxic cyanobacteria strains of Microcystis, Synechocystis, Pseudanabaena, and Oscillatoria. These strains were isolated from various water bodies including natural lakes, reservoirs, and ponds located in central regions of Morocco. The isolation, culture, and biomass production of these strains was made on Z8 or BG13 media under laboratory controlled conditions. The hepatotoxicity of cyanobacterial lyophilized material was confirmed by mouse bioassays. The amount of microcystins produced by each strain was determined by the enzyme-linked immunosorbent assay (ELISA). The detection and identification of microcystin variants was performed by high performance liquid chromatography (HPLC) with photodiode array detection. Almost all strains showed medium to high toxicity, the estimated LD50 i.p. mice bioassay ranged between 28 to 350 mg/kg body weight. The concentrations of microcystins varied between 2.16 to 944 micrograms/g and 26.8 to 1884 micrograms/g dry weight determined by ELISA and HPLC, respectively. The screening of bloom-forming and microcystin producer cyanobacteria strains in these fresh water bodies leads us to propose the need for the establishment of a survey of cyanobacteria and a cyanotoxin-monitoring program.
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Affiliation(s)
- B Oudra
- University Cadi Ayyad, Faculty of Sciences Semlalia-Marrakech, Department of Biology, P.O. Box 2390, Marrakech 40 000, Morocco
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Vasconcelos V, Oliveira S, Teles FO. Impact of a toxic and a non-toxic strain of Microcystis aeruginosa on the crayfish Procambarus clarkii. Toxicon 2001; 39:1461-70. [PMID: 11478953 DOI: 10.1016/s0041-0101(01)00105-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The occurrence of cyanobacteria in many water bodies where crayfish such as Procambarus clarkii are abundant leads to the possibility of toxin accumulation and food chain transfer. This paper describes the accumulation and depuration of microcystins from a microcystin and a non-microcystin producing strain of Microcystis aeruginosa, on the survivorship, growth and nutritional status of P. clarkii. Crayfish larvae were resistant to cyanobacteria and their toxins, surviving cyanobacteria densities during acute exposures. Juvenile crayfish tolerated toxic cyanobacteria better than non-toxic ones. This effect was also observed when analysing nutritional status of crayfish fed toxic and non-toxic cyanobacteria with the former having better lipid and protein contents than those fed non-toxic Microcystis. P. clarkii accumulated up to 2.9 microg MCYST/dry crayfish weight and the depuration pattern was similar to that observed for mussels by other authors. Due to the fact that the major part of the toxin is accumulated in the intestine and in the hepatopancreas, there is no significant risk in terms of human health if these parts are removed prior to crayfish consumption. Nevertheless, their use in dairy food and the possible transference of toxins along food chains should not be disregarded.
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Affiliation(s)
- V Vasconcelos
- Departamento de Zoologia e Antropologia, Faculdade de Ciências, Praça Gomes Teixeira, 4050, Porto, Portugal.
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