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Mohamed ZA, Elnour RO, Alamri S, Hashem M, Campos A, Vasconcelos V, Badawye H. Presence of the neurotoxin β-N-methylamino-L-alanine in irrigation water and accumulation in cereal grains with human exposure risk. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-33188-y. [PMID: 38635096 DOI: 10.1007/s11356-024-33188-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 03/29/2024] [Indexed: 04/19/2024]
Abstract
The present study demonstrates the presence of the neurotoxin β-N-methylamino-L-alanine and its cyanobacterial producers in irrigation water and grains of some cereal plants from farmlands irrigated with Nile River water in Egypt. BMAA detected by LC-MS/MS in phytoplankton samples was found at higher concentrations of free form (0.84-11.4 μg L-1) than of protein-bound form (0.16-1.6 μg L-1), in association with the dominance of cyanobacteria in irrigation water canals. Dominant cyanobacterial species isolated from these irrigation waters including Aphanocapsa planctonica, Chroococcus minutus, Dolichospermum lemmermanni, Nostoc commune, and Oscillatoria tenuis were found to produce different concentrations of free (4.8-71.1 µg g-1 dry weight) and protein-bound (0.1-11.4 µg g-1 dry weight) BMAA. In the meantime, BMAA was also detected in a protein-bound form only in grains of corn (3.87-4.51 µg g-1 fresh weight) and sorghum (5.1-7.1 µg g-1 fresh weight) plants, but not in wheat grains. The amounts of BMAA accumulated in these grains correlated with BMAA concentrations detected in relevant irrigation water canals. The presence of BMAA in cereal grains would constitute a risk to human and animal health upon consumption of contaminated grains. The study, therefore, suggests continuous monitoring of BMAA and other cyanotoxins in irrigation waters and edible plants to protect the public against exposure to such potent toxins.
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Affiliation(s)
- Zakaria A Mohamed
- Department of Botany and Microbiology, Faculty of Science, Sohag University, Sohag, 82524, Egypt.
| | - Rehab O Elnour
- Biology Department, Faculty of Sciences and Arts, Dahran Al-Janoub, King Khalid University, Abha, Saudi Arabia
| | - Saad Alamri
- Department of Biology, College of Science, King Khalid University, Abha, 61413, Saudi Arabia
| | - Mohamed Hashem
- Department of Biology, College of Science, King Khalid University, Abha, 61413, Saudi Arabia
| | - Alexandre Campos
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Terminal de Cruzeiros Do Porto de Leixões, Av. General Norton de Matos, S/N, 4450-208, Matosinhos, Portugal
| | - Vitor Vasconcelos
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Terminal de Cruzeiros Do Porto de Leixões, Av. General Norton de Matos, S/N, 4450-208, Matosinhos, Portugal
- Departament of Biology, Faculty of Sciences, University of Porto, Rua Do Campo Alegre, 4169-007, Porto, Portugal
| | - Hanan Badawye
- Department of Botany and Microbiology, Faculty of Science, Sohag University, Sohag, 82524, Egypt
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Stipa G, Ancidoni A, Vanacore N, Bellomo G. Raw Water and ALS: A Unifying Hypothesis for the Environmental Agents Involved in ALS. Ann Neurosci 2023; 30:124-132. [PMID: 37706096 PMCID: PMC10496797 DOI: 10.1177/09727531221120358] [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: 05/25/2022] [Accepted: 07/22/2022] [Indexed: 09/15/2023] Open
Abstract
Different studies identified the presence of several altered genes in familial and sporadic amyotrophic lateral sclerosis (ALS) forms. The experimental data, together with the epidemiological data, would seem to suggest the existence of molecular mechanisms (e.g., axonal transport) related to these genes, together with a susceptibility of the same genes to certain environmental factors that would therefore suggest an impact of the environment on the etiopathogenesis of ALS. In our review, we considered the most relevant environmental clusters around the world, collecting different hypotheses and underlining common environmental factors among the different clusters. Moreover, further epidemiological data identified a higher risk of ALS in professional athletes and, in particular, in soccer and football players. Despite this increased risk of ALS highlighted by the epidemiological evidence in aforementioned sports, the mechanisms remain unclear. At last, the use of raw water has been associated with ALS risk. The aim of the present review is to characterize a possible relationship between these clusters, to be explored in the context of the interaction between genetic and environmental factors on the etiopathogenesis of ALS.
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Affiliation(s)
- Giuseppe Stipa
- Clinical Neurophysiology Division, Neuroscience Department, S. Maria University Hospital, Terni, Italy
| | - Antonio Ancidoni
- National Center for Disease Prevention and Health Promotion, National Institute of Health (ISS), Roma, Italy
| | - Nicola Vanacore
- National Center for Disease Prevention and Health Promotion, National Institute of Health (ISS), Roma, Italy
| | - Guido Bellomo
- National Center for Disease Prevention and Health Promotion, National Institute of Health (ISS), Roma, Italy
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3
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Cyanotoxins uptake and accumulation in crops: Phytotoxicity and implications on human health. Toxicon 2022; 211:21-35. [DOI: 10.1016/j.toxicon.2022.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/03/2022] [Accepted: 03/07/2022] [Indexed: 12/16/2022]
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4
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Bouaïcha N, Metcalf JS, Porzani SJ, Konur O. Plant-cyanobacteria interactions: Beneficial and harmful effects of cyanobacterial bioactive compounds on soil-plant systems and subsequent risk to animal and human health. PHYTOCHEMISTRY 2021; 192:112959. [PMID: 34649057 DOI: 10.1016/j.phytochem.2021.112959] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 09/10/2021] [Accepted: 09/15/2021] [Indexed: 05/17/2023]
Abstract
Plant-cyanobacteria interactions occur in different ways and at many different levels, both beneficial and harmful. Plant-cyanobacteria interactions, as a beneficial symbiosis, have long been demonstrated in rice-growing areas (Poaceae) where the most efficient nitrogen-fixing cyanobacteria are present in paddies. Moreover, cyanobacteria may in turn produce and/or secrete numerous bioactive compounds that have plant growth-promoting abilities or that may make the plant more resistant to abiotic or biotic stress. In recent years, there has been a growing worldwide interest in the use of cyanobacterial biomass as biofertilizers to replace chemical fertilizers, in part to overcome increasing organic-farming demands. However, the potential presence of harmful cyanotoxins has delayed the use of such cyanobacterial biomass, which can be found in large quantities in freshwater ecosystems around the world. In this review, we describe the existing evidence for the positive benefit of plant-cyanobacteria interactions and discuss the use of cyanobacterial biomass as biofertilizers and its growing worldwide interest. Although mass cyanobacterial blooms and scums are a current and emerging threat to the degradation of ecosystems and to animal and human health, they may serve as a source of numerous bioactive compounds with multiple positive effects that could be of use as an alternative to chemical fertilizers in the context of sustainable development.
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Affiliation(s)
- Noureddine Bouaïcha
- Laboratory Ecology, Systematic and Evolution, UMR 8079 Univ. Paris-Sud, CNRS, AgroParisTech, University Paris-Saclay, 91405, Orsay, France
| | | | - Samaneh Jafari Porzani
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Ozcan Konur
- Formerly, Ankara Yildirim Beyazit University, Ankara, Turkey
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5
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Maity S, Guchhait R, Chatterjee A, Pramanick K. Co-occurrence of co-contaminants: Cyanotoxins and microplastics, in soil system and their health impacts on plant - A comprehensive review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148752. [PMID: 34225156 DOI: 10.1016/j.scitotenv.2021.148752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/25/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
Cyanotoxins (CTX) and micro/nanoplastics (M/NP) are ubiquitously distributed in every environmental compartment. But the distribution, abundance and associated ecological risks of CTX are still poorly understood in soil system. On the other hand, M/NP could serve as vectors for persistent organic/inorganic pollutants in the natural environment through the sorption of pollutants onto them. Thus, co-occurrence of CTX and M/NP in soils suggests the sorption of CTX onto M/NP. So, major aim of this review is to understand the relevance of CTX and M/NP in soils as co-contaminants, possible interactions between them and ecological risks of CTX in terms of phytotoxicity. In this study, we comprehensively discuss different sources and fate of CTX and the sorption of CTX onto M/NP in soil system, considering the partition coefficient of different phases of soil and mass balance. Phytotoxicity of CTX, CTX mixture and co-contaminants has also been discussed with insights on the mechanism of action. This study indicates the need for the evaluation of sorption between co-contaminants, especially CTX and M/NP, and their phytotoxicity assessment using environmentally relevant concentrations.
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Affiliation(s)
- Sukhendu Maity
- Integrative Biology Research Unit (IBRU), Presidency University, Kolkata, West Bengal, India
| | - Rajkumar Guchhait
- Integrative Biology Research Unit (IBRU), Presidency University, Kolkata, West Bengal, India; Department of zoology, Mahishadal Raj College, Purba Medinipur, West Bengal, India
| | - Ankit Chatterjee
- Integrative Biology Research Unit (IBRU), Presidency University, Kolkata, West Bengal, India
| | - Kousik Pramanick
- Integrative Biology Research Unit (IBRU), Presidency University, Kolkata, West Bengal, India.
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6
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Samardzic K, Steele JR, Violi JP, Colville A, Mitrovic SM, Rodgers KJ. Toxicity and bioaccumulation of two non-protein amino acids synthesised by cyanobacteria, β-N-Methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB), on a crop plant. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 208:111515. [PMID: 33099142 DOI: 10.1016/j.ecoenv.2020.111515] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/02/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
In order to study the toxicity of the cyanobacterial non-protein amino acids (NPAAs) L-β-N-methylamino-L-alanine (BMAA) and its structural isomer L-2,4-diaminobutyric acid (DAB) in the forage crop plant alfalfa (Medicago sativa), seedlings were exposed to NPAA-containing media for four days. Root growth was significantly inhibited by both treatments. The content of derivatised free and protein-bound BMAA and DAB in seedlings was then analysed by LC-MS/MS. Both NPAAs were detected in free and protein-bound fractions with higher levels detected in free fractions. Compared to shoots, there was approximately tenfold more BMAA and DAB in alfalfa roots. These results suggest that NPAAs might be taken up into crop plants from contaminated irrigation water and enter the food chain. This may present an exposure pathway for NPAAs in humans.
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Affiliation(s)
- Kate Samardzic
- School of Life Sciences, University of Technology Sydney, Ultimo, Australia.
| | - Joel R Steele
- School of Life Sciences, University of Technology Sydney, Ultimo, Australia
| | - Jake P Violi
- School of Life Sciences, University of Technology Sydney, Ultimo, Australia
| | - Anne Colville
- School of Life Sciences, University of Technology Sydney, Ultimo, Australia
| | - Simon M Mitrovic
- School of Life Sciences, University of Technology Sydney, Ultimo, Australia
| | - Kenneth J Rodgers
- School of Life Sciences, University of Technology Sydney, Ultimo, Australia
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7
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Nunes-Costa D, Magalhães JD, G-Fernandes M, Cardoso SM, Empadinhas N. Microbial BMAA and the Pathway for Parkinson's Disease Neurodegeneration. Front Aging Neurosci 2020; 12:26. [PMID: 32317956 PMCID: PMC7019015 DOI: 10.3389/fnagi.2020.00026] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/23/2020] [Indexed: 12/12/2022] Open
Abstract
The neurotoxin β-N-methylamino-L-alanine (BMAA) is a natural non-proteinogenic diamino acid produced by several species of both prokaryotic (cyanobacteria) and eukaryotic (diatoms and dinoflagellates) microorganisms. BMAA has been shown to biomagnify through the food chain in some ecosystems, accumulating for example in seafood such as shellfish and fish, common dietary sources of BMAA whose ingestion may have possible neuronal consequences. In addition to its excitotoxic potential, BMAA has been implicated in protein misfolding and aggregation, inhibition of specific enzymes and neuroinflammation, all hallmark features of neurodegenerative diseases. However, the exact molecular mechanisms of neurotoxicity remain to be elucidated in detail. Although BMAA is commonly detected in its free form, complex BMAA-containing molecules have also been identified such as the paenilamicins, produced by an insect gut bacterial pathogen. On the other hand, production of BMAA or BMAA-containing molecules by members of the human gut microbiota, for example by non-photosynthetic cyanobacteria, the Melainabacteria, remains only hypothetical. In any case, should BMAA reach the gut it may interact with cells of the mucosal immune system and neurons of the enteric nervous system (ENS) and possibly target the mitochondria. Here, we review the available evidence and hint on possible mechanisms by which chronic exposure to dietary sources of this microbial neurotoxin may drive protein misfolding and mitochondrial dysfunction with concomitant activation of innate immune responses, chronic low-grade gut inflammation, and ultimately the neurodegenerative features observed across the gut-brain axis in Parkinson's disease (PD).
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Affiliation(s)
- Daniela Nunes-Costa
- CNC–Center for Neuroscience and Cell
Biology, University of Coimbra, Coimbra,
Portugal
- Ph.D. Programme in Biomedicine and Experimental
Biology (PDBEB), Institute for Interdisciplinary Research, University of
Coimbra, Coimbra,
Portugal
| | - João Duarte Magalhães
- CNC–Center for Neuroscience and Cell
Biology, University of Coimbra, Coimbra,
Portugal
- Ph.D. Programme in Biomedicine and Experimental
Biology (PDBEB), Institute for Interdisciplinary Research, University of
Coimbra, Coimbra,
Portugal
| | - Maria G-Fernandes
- CNC–Center for Neuroscience and Cell
Biology, University of Coimbra, Coimbra,
Portugal
| | - Sandra Morais Cardoso
- CNC–Center for Neuroscience and Cell
Biology, University of Coimbra, Coimbra,
Portugal
- Institute of Cellular and Molecular Biology,
Faculty of Medicine, University of Coimbra,
Coimbra, Portugal
| | - Nuno Empadinhas
- CNC–Center for Neuroscience and Cell
Biology, University of Coimbra, Coimbra,
Portugal
- Institute for Interdisciplinary Research
(IIIUC), University of Coimbra, Coimbra,
Portugal
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8
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The Cyanotoxin and Non-protein Amino Acid β-Methylamino-L-Alanine (L-BMAA) in the Food Chain: Incorporation into Proteins and Its Impact on Human Health. Neurotox Res 2019; 36:602-611. [DOI: 10.1007/s12640-019-00089-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/21/2019] [Accepted: 07/12/2019] [Indexed: 12/31/2022]
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9
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Violi JP, Mitrovic SM, Colville A, Main BJ, Rodgers KJ. Prevalence of β-methylamino-L-alanine (BMAA) and its isomers in freshwater cyanobacteria isolated from eastern Australia. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 172:72-81. [PMID: 30682636 DOI: 10.1016/j.ecoenv.2019.01.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
Environmental exposure to the amino acid β-methylamino-L-alanine (BMAA) was linked to the high incidence of neurodegenerative disease first reported on the island of Guam in the 1940s and has more recently been implicated in an increased incidence of amyotrophic lateral sclerosis (ALS) in parts of the USA. BMAA has been shown to be produced by a range of cyanobacteria and some marine diatoms and dinoflagellates in different parts of the world. BMAA is commonly found with two of its constitutional isomers: 2,4- diaminobutyric acid (2,4-DAB) and N-(2-aminoethyl) glycine (AEG). These isomers are thought to be co-produced by the same organisms that produce BMAA and MS/MS analysis following LC separation can add an additional level of specificity over LC-FL. Although the presence of BMAA and 2,4-DAB in surface scum samples from several sites in Australia has been reported, which Australian cyanobacterial species are capable of BMAA, 2,4-DAB and AEG production remains unknown. The aims of the present studies were to identify some of the cyanobacterial genera or species that can produce BMAA, 2,4-DAB and AEG in freshwater cyanobacteria blooms in eastern Australia. Eleven freshwater sites were sampled and from these, 19 single-species cyanobacterial cultures were established. Amino acids were extracted from cyanobacterial cultures and analysed using liquid chromatography-tandem mass spectrometry. BMAA was detected in 17 of the 19 isolates, 2,4-DAB was detected in all isolates, and AEG was detected in 18 of the 19 isolates, showing the prevalence of these amino acids in Australian freshwater cyanobacteria. Concentrations of all three isomers in Australian cyanobacteria were generally higher than the concentrations reported elsewhere. This study confirmed the presence of BMAA and its isomers in cyanobacteria isolated from eastern Australian freshwater systems, and determined which Australian cyanobacterial genera or species were capable of producing them when cultured under laboratory conditions.
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Affiliation(s)
- Jake P Violi
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Simon M Mitrovic
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Anne Colville
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Brendan J Main
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Kenneth J Rodgers
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia.
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10
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Li B, Yu S, Li G, Chen X, Huang M, Liao X, Li H, Hu F, Wu J. Transfer of a cyanobacterial neurotoxin, β-methylamino-l-alanine from soil to crop and its bioaccumulation in Chinese cabbage. CHEMOSPHERE 2019; 219:997-1001. [PMID: 30682765 DOI: 10.1016/j.chemosphere.2018.12.104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 11/29/2018] [Accepted: 12/14/2018] [Indexed: 06/09/2023]
Abstract
Most cyanobacteria can synthesize the notorious neurotoxin β-methylamino-l-alanine (BMAA) that is transferred and bioaccumulated through natural food webs of aquatic ecosystems and ultimately arises the potential human health risks by the consumption of BMAA-contaminated aquatic products. Fertilization of cyanobacterial composts in farmlands may also lead to BMAA contamination in soil and its possible transfer and bioaccumulation within major crops, thereby threatening human health. In this study, we first detected a high level of BMAA (1.8-16.3 μg g-1) in cyanobacterial composts. In order to assess the health risks from cyanobacterial composts, we planted Chinese cabbage, a favourite vegetable in China, in BMAA-contaminated soil (4.0 μg BMAA/g soil) and detected the levels of free and protein-associated BMAA in soil and crop organs during the whole growth cycle by HPLC-MS/MS, respectively. Our results demonstrated that BMAA indeed transferred from soil to root, stem and leaf of Chinese cabbage during the growth cycle. The BMAA level finally accumulated in the edible portions was much higher than the initial level in soil, including 13.82 μg g-1 in leaf and 4.71 μg g-1 in stem. The discovery of the neurotoxin BMAA in this vegetable, an ending in human consumption, not only provides a BMAA transfer pathway in farmland ecosystems, but also is alarming and requires attention due to the potential risk of cyanobacterial composts to human health.
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Affiliation(s)
- Bo Li
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Shanshan Yu
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Gen Li
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Xu Chen
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Meng Huang
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Xuewei Liao
- Center of Analysis and Testing, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Huixin Li
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, Jiangsu, China
| | - Feng Hu
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Jun Wu
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu, China.
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11
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Esterhuizen-Londt M, Pflugmacher S. Vegetables cultivated with exposure to pure and naturally occurring β-N-methylamino-L-alanine (BMAA) via irrigation. ENVIRONMENTAL RESEARCH 2019; 169:357-361. [PMID: 30508701 DOI: 10.1016/j.envres.2018.11.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/16/2018] [Accepted: 11/18/2018] [Indexed: 06/09/2023]
Abstract
Bioaccumulation and biomagnification of β-N-methylamino-L-alanine (BMAA), a potent neurotoxin, has been demonstrated in various food webs. It is alarming as this intensification of BMAA will result in exposure to higher concentrations from a direct cyanobacterial source. As more food items are being identified as a source of BMAA and with the large variations in BMAA content, the aim of the present study was to evaluate BMAA uptake by, and accumulation in, two commonly consumed vegetables, Lactuca sativa and Allium fistulosum. Plants exposed to pure BMAA in controlled laboratory experiments, as well as vegetables naturally irrigated with water containing a BMAA producing cyanobacterial bloom were evaluated during growth and ripening. In the laboratory exposures, free BMAA was detected in both the edible ripe parts of L. sativa and A. fistulosum after 60 days of exposure to a total of 4.5 µg BMAA. However, in the bloom exposure samples no BMAA could be detected in the ripe vegetables of A. fistulosum, Cucurbita pepo, or Brassica rapa chinensis. The study emphasises the need to further screen items for BMAA to understand the human exposure risk as well as the difference between BMAA uptake patterns with free BMAA and that contained in cyanobacterial cells.
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Affiliation(s)
- Maranda Esterhuizen-Londt
- University of Helsinki, Faculty of Biological and Environmental Sciences, Ecosystems and Environment Research programme, Niemenkatu 73, Lahti FI-15140, Finland.
| | - Stephan Pflugmacher
- University of Helsinki, Faculty of Biological and Environmental Sciences, Ecosystems and Environment Research programme, Niemenkatu 73, Lahti FI-15140, Finland; Korean Institute of Science and Technology Europe (KIST Europe), Joint Laboratory of Applied Ecotoxicology, Campus 7.1, Saarbrücken, Germany
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12
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Scott L, Downing T. Dose-Dependent Adult Neurodegeneration in a Rat Model After Neonatal Exposure to β-N-Methylamino-l-Alanine. Neurotox Res 2019; 35:711-723. [DOI: 10.1007/s12640-019-9996-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/27/2018] [Accepted: 01/08/2019] [Indexed: 01/18/2023]
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13
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Scott LL, Downing S, Downing T. Potential for dietary exposure to β-N-methylamino-L-alanine and microcystin from a freshwater system. Toxicon 2018; 150:261-266. [PMID: 29920255 DOI: 10.1016/j.toxicon.2018.06.076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 06/13/2018] [Accepted: 06/14/2018] [Indexed: 01/17/2023]
Abstract
The suggested link between β-N-methylamino-L-alanine (BMAA) and the onset of neurodegenerative diseases and the detection of this cyanotoxin in aquatic organisms has prompted research into the potential human exposure risk associated with sourcing food items from eutrophied water bodies worldwide. The Hartbeespoort Dam reservoir in the North West province of South Africa has persistent cyanobacterial blooms and is used extensively by anglers, many of whom consume their catch. The commercial sale of fish species harvested from this reservoir as part of a recent biomanipulative remediation strategy may pose an additional hazard. BMAA and Microcystins (MC) were detected in fish sourced from this reservoir. BMAA levels of up to 1630 ng g-1 dry weight and MC concentrations of up to 29.44 ng g-1 dry weight were detected in fish sourced during an extensive bloom episode, with a clear correlation between the total amount of BMAA detected in the fish muscle tissue and their relative position in the Hartbeespoort Dam reservoir food web. Interestingly, fish sourced from this reservoir in winter when dense cyanobacterial blooms were lacking contained BMAA levels of up to 3055 ng g-1 dry weight. We also comment on the observed seasonal variations of BMAA levels in phytoplankton and fish sourced from this water body as well as the potential exposure risks associated with harvesting food items from this reservoir.
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Affiliation(s)
- Laura L Scott
- Department of Biochemistry & Microbiology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Simoné Downing
- Department of Biochemistry & Microbiology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Tim Downing
- Department of Biochemistry & Microbiology, Nelson Mandela University, Port Elizabeth, South Africa.
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14
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Main BJ, Bowling LC, Padula MP, Bishop DP, Mitrovic SM, Guillemin GJ, Rodgers KJ. Detection of the suspected neurotoxin β-methylamino-l-alanine (BMAA) in cyanobacterial blooms from multiple water bodies in Eastern Australia. HARMFUL ALGAE 2018; 74:10-18. [PMID: 29724339 DOI: 10.1016/j.hal.2018.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/09/2018] [Accepted: 03/11/2018] [Indexed: 06/08/2023]
Abstract
The emerging toxin β-methylamino-l-alanine (BMAA) has been linked to the development of a number of neurodegenerative diseases in humans including amyotrophic lateral sclerosis (ALS), Alzheimer's disease, and Parkinson's disease. BMAA has been found to be produced by a range of cyanobacteria, diatoms, and dinoflagellates worldwide, and is present in freshwater, saltwater, and terrestrial ecosystems. Surface scum samples were collected from waterways in rural and urban New South Wales, Australia and algal species identified. Reverse phase liquid chromatography-tandem mass spectrometry was used to analyse sixteen cyanobacterial scum for the presence of BMAA as well as its toxic structural isomer 2,4-diaminobutyric acid (2,4-DAB). BMAA was detected in ten of the samples analysed, and 2,4-DAB in all sixteen. The presence of these toxins in water used for agriculture raises concerns for public health and food security in Australia.
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Affiliation(s)
- Brendan J Main
- School of Life Sciences, University of Technology Sydney, NSW, 2007, Australia
| | - Lee C Bowling
- School of Life Sciences, University of Technology Sydney, NSW, 2007, Australia; DPI Water, NSW Department of Primary Industries, Menangle, NSW, 2568, Australia
| | - Matthew P Padula
- School of Life Sciences, University of Technology Sydney, NSW, 2007, Australia
| | - David P Bishop
- Elemental Bio-imaging Facility, School of Mathematical and Physical Sciences, University of Technology Sydney, NSW, 2007, Australia
| | - Simon M Mitrovic
- School of Life Sciences, University of Technology Sydney, NSW, 2007, Australia
| | - Gilles J Guillemin
- MND Centre, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Kenneth J Rodgers
- School of Life Sciences, University of Technology Sydney, NSW, 2007, Australia.
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15
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Contardo-Jara V, Schwanemann T, Esterhuizen-Londt M, Pflugmacher S. Protein association of β-N-methylamino-L-alanine in Triticum aestivum via irrigation. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2018; 35:731-739. [DOI: 10.1080/19440049.2018.1427283] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Valeska Contardo-Jara
- Chair of Ecological Impact Research and Ecotoxicology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Torsten Schwanemann
- Chair of Ecological Impact Research and Ecotoxicology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Maranda Esterhuizen-Londt
- Chair of Ecological Impact Research and Ecotoxicology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Stephan Pflugmacher
- Chair of Ecological Impact Research and Ecotoxicology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
- Joint Laboratory of Applied Ecotoxicology, Korea Institute of Science and Technology Europe (KIST), Saarbrücken, Germany
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16
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Downing S, Scott LL, Zguna N, Downing TG. Human Scalp Hair as an Indicator of Exposure to the Environmental Toxin β-N-Methylamino-l-alanine. Toxins (Basel) 2017; 10:E14. [PMID: 29280954 PMCID: PMC5793101 DOI: 10.3390/toxins10010014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/18/2017] [Accepted: 12/25/2017] [Indexed: 12/12/2022] Open
Abstract
Dietary or aerosol exposure to the environmental neurotoxin β-N-methylamino-l-alanine (BMAA) is a putative risk factor for the development of sporadic neurodegenerative disease. There are many potential sources of BMAA in the environment, but BMAA presence and quantities are highly variable. It has been suggested that BMAA in human hair may serve as an indicator of exposure. We sought to evaluate the use of the BMAA content of human scalp hair as an indicator of exposure, as well as the correlation between specific lifestyle or dietary habits, reported as hypothesised exposure risk factors, and BMAA in hair. Scalp hair samples and questionnaires were collected from participants in a small residential village surrounding a freshwater impoundment renowned for toxic cyanobacterial blooms. Data suggested a positive correlation between hair BMAA content and consumption of shellfish, and possibly pork. No statistically significant correlations were observed between hair BMAA content and residential proximity to the water or any other variable. Hair BMAA content was highly variable, and in terms of exposure, probably reflects primarily dietary exposure. However, the BMAA content of human hair may be affected to a great extent by several other factors, and as such, should be used with caution when evaluating human BMAA exposure, or correlating exposure to neurodegenerative disease incidence.
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Affiliation(s)
- Simoné Downing
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
| | - Laura Louise Scott
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
| | - Nadezda Zguna
- Unit for Analytical Chemistry, Department of Environmental Science and Analytical Chemistry, Stockholm University, SE 106 91 Stockholm, Sweden.
| | - Timothy Grant Downing
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
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17
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Scott LL, Downing TG. Β-N-Methylamino-L-Alanine (BMAA) Toxicity Is Gender and Exposure-Age Dependent in Rats. Toxins (Basel) 2017; 10:E16. [PMID: 29280981 PMCID: PMC5793103 DOI: 10.3390/toxins10010016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/21/2017] [Accepted: 12/26/2017] [Indexed: 12/21/2022] Open
Abstract
Cyanobacterial β-N-methylamino-L-alanine (BMAA) has been suggested as a causative or contributory factor in the development of several neurodegenerative diseases. However, no BMAA animal model has adequately shown clinical or behavioral symptoms that correspond to those seen in either Alzheimer's Disease (AD), Amyotrophic Lateral Sclerosis (ALS) or Parkinson's Disease (PD). We present here the first data that show that when neonatal rats were exposed to BMAA on postnatal days 3, 4 and 5, but not on gestational day 14 or postnatally on days 7 or 10, several AD and/or PD-related behavioral, locomotor and cognitive deficits developed. Male rats exhibited severe unilateral hindlimb splay while whole body tremors could be observed in exposed female rats. BMAA-exposed rats failed to identify and discriminate a learned odor, an early non-motor symptom of PD, and exhibited decreased locomotor activity, decreased exploration and increased anxiety in the open field test. Alterations were also observed in the rats' natural passive defense mechanism, and potential memory deficits and changes to the rat's natural height avoidance behavior could be observed as early as PND 30. Spatial learning, short-term working, reference and long-term memory were also impaired in 90-day-old rats that had been exposed to a single dose of BMAA on PND 3-7. These data suggest that BMAA is a developmental neurotoxin, with specific target areas in the brain and spinal cord.
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Affiliation(s)
- Laura Louise Scott
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
| | - Timothy Grant Downing
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
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18
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Chernoff N, Hill DJ, Diggs DL, Faison BD, Francis BM, Lang JR, Larue MM, Le TT, Loftin KA, Lugo JN, Schmid JE, Winnik WM. A critical review of the postulated role of the non-essential amino acid, β-N-methylamino-L-alanine, in neurodegenerative disease in humans. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2017; 20:1-47. [PMID: 28598725 PMCID: PMC6503681 DOI: 10.1080/10937404.2017.1297592] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The compound BMAA (β-N-methylamino-L-alanine) has been postulated to play a significant role in four serious neurological human diseases: Amyotrophic Lateral Sclerosis/Parkinsonism Dementia Complex (ALS/PDC) found on Guam, and ALS, Parkinsonism, and dementia that occur globally. ALS/PDC with symptoms of all three diseases first came to the attention of the scientific community during and after World War II. It was initially associated with cycad flour used for food because BMAA is a product of symbiotic cycad root-dwelling cyanobacteria. Human consumption of flying foxes that fed on cycad seeds was later suggested as a source of BMAA on Guam and a cause of ALS/PDC. Subsequently, the hypothesis was expanded to include a causative role for BMAA in other neurodegenerative diseases including Alzheimer's disease (AD) through exposures attributed to proximity to freshwaters and/or consumption of seafood due to its purported production by most species of cyanobacteria. The hypothesis that BMAA is the critical factor in the genesis of these neurodegenerative diseases received considerable attention in the medical, scientific, and public arenas. This review examines the history of ALS/PDC and the BMAA-human disease hypotheses; similarities and differences between ALS/PDC and the other diseases with similar symptomologies; the relationship of ALS/PDC to other similar diseases, studies of BMAA-mediated effects in lab animals, inconsistencies and data gaps in the hypothesis; and other compounds and agents that were suggested as the cause of ALS/PDC on Guam. The review concludes that the hypothesis of a causal BMAA neurodegenerative disease relationship is not supported by existing data.
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Affiliation(s)
- N. Chernoff
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA
| | - D. J. Hill
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA
| | - D. L. Diggs
- Oak Ridge Institute for Science and Education Internship/Research Participation Program at the U.S. Environmental Protection Agency, NHEERL, Research Triangle Park, NC, USA
| | - B. D. Faison
- U.S. Environmental Protection Agency, Office of Water, Office of Science and Technology, Washington, DC, USA
| | - B. M. Francis
- Department of Entomology, University of Illinois, Champaign-Urbana, IL, USA
| | - J. R Lang
- Oak Ridge Institute for Science and Education Internship/Research Participation Program at the U.S. Environmental Protection Agency, NHEERL, Research Triangle Park, NC, USA
| | - M. M. Larue
- Oak Ridge Institute for Science and Education Internship/Research Participation Program at the U.S. Environmental Protection Agency, NHEERL, Research Triangle Park, NC, USA
| | - T.-T. Le
- Oak Ridge Institute for Science and Education Internship/Research Participation Program at the U.S. Environmental Protection Agency, NHEERL, Research Triangle Park, NC, USA
| | | | - J. N. Lugo
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, USA
| | - J. E. Schmid
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA
| | - W. M. Winnik
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA
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19
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Scott LL, Downing S, Downing TG. The Evaluation of BMAA Inhalation as a Potential Exposure Route Using a rat Model. Neurotox Res 2017; 33:6-14. [DOI: 10.1007/s12640-017-9742-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/12/2017] [Accepted: 04/21/2017] [Indexed: 11/25/2022]
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20
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Popova AA, Koksharova OA. Neurotoxic Non-proteinogenic Amino Acid β-N-Methylamino-L-alanine and Its Role in Biological Systems. BIOCHEMISTRY (MOSCOW) 2017; 81:794-805. [PMID: 27677549 DOI: 10.1134/s0006297916080022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Secondary metabolites of photoautotrophic organisms have attracted considerable interest in recent years. In particular, molecules of non-proteinogenic amino acids participating in various physiological processes and capable of producing adverse ecological effects have been actively investigated. For example, the non-proteinogenic amino acid β-N-methylamino-L-alanine (BMAA) is neurotoxic to animals including humans. It is known that BMAA accumulation via the food chain can lead to development of neurodegenerative diseases in humans such as Alzheimer's and Parkinson's diseases as well as amyotrophic lateral sclerosis. Moreover, BMAA can be mistakenly incorporated into a protein molecule instead of serine. Natural sources of BMAA and methods for its detection are discussed in this review, as well as the role of BMAA in metabolism of its producers and possible mechanisms of toxicity of this amino acid in different living organisms.
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Affiliation(s)
- A A Popova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, 123182, Russia.
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21
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Lahrouni M, Oufdou K, El Khalloufi F, Benidire L, Albert S, Göttfert M, Caviedes MA, Rodriguez-Llorente ID, Oudra B, Pajuelo E. Microcystin-tolerant Rhizobium protects plants and improves nitrogen assimilation in Vicia faba irrigated with microcystin-containing waters. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:10037-10049. [PMID: 26865488 DOI: 10.1007/s11356-016-6223-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 02/01/2016] [Indexed: 06/05/2023]
Abstract
Irrigation of crops with microcystins (MCs)-containing waters-due to cyanobacterial blooms-affects plant productivity and could be a way for these potent toxins entering the food chain. This study was performed to establish whether MC-tolerant rhizobia could benefit growth, nodulation, and nitrogen metabolism of faba bean plants irrigated with MC-containing waters. For that, three different rhizobial strains-with different sensitivity toward MCs-were used: RhOF96 (most MC-sensitive strain), RhOF125 (most MC-tolerant strain), or Vicz1.1 (reference strain). As a control, plants grown without rhizobia and fertilized by NH4NO3 were included in the study. MC exposure decreased roots (30-37 %) and shoots (up to 15 %) dry weights in un-inoculated plants, whereas inoculation with rhizobia protects plants toward the toxic effects of MCs. Nodulation and nitrogen content were significantly impaired by MCs, with the exception of plants inoculated with the most tolerant strain RhOF125. In order to deep into the effect of inoculation on nitrogen metabolism, the nitrogen assimilatory enzymes (glutamine synthetase (GS) and glutamate synthase (GOGAT)) were investigated: Fertilized plants showed decreased levels (15-30 %) of these enzymes, both in shoots and roots. By contrast, inoculated plants retained the levels of these enzymes in shoots and roots, as well as the levels of NADH-GOGAT activity in nodules. We conclude that the microcystin-tolerant Rhizobium protects faba bean plants and improves nitrogen assimilation when grown in the presence of MCs.
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Affiliation(s)
- Majida Lahrouni
- Laboratory of Biology and Biotechnology of Microorganisms, Environmental Microbiology and Toxicology Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, PO Box 2390, Marrakech, Morocco
- Technische Universität Dresden, Institut für Genetik, Helmholtzstr. 10, D-01069, Dresden, Germany
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, c/ Profesor García González, 2, 41012, Sevilla, Spain
| | - Khalid Oufdou
- Laboratory of Biology and Biotechnology of Microorganisms, Environmental Microbiology and Toxicology Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, PO Box 2390, Marrakech, Morocco
| | - Fatima El Khalloufi
- Laboratory of Biology and Biotechnology of Microorganisms, Environmental Microbiology and Toxicology Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, PO Box 2390, Marrakech, Morocco
- University Hassan 1st. Polydisciplinary Faculty of Khouribga, BP. 145, 25000, Khouribga, Morocco
| | - Loubna Benidire
- Laboratory of Biology and Biotechnology of Microorganisms, Environmental Microbiology and Toxicology Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, PO Box 2390, Marrakech, Morocco
| | - Susann Albert
- Technische Universität Dresden, Institut für Genetik, Helmholtzstr. 10, D-01069, Dresden, Germany
| | - Michael Göttfert
- Technische Universität Dresden, Institut für Genetik, Helmholtzstr. 10, D-01069, Dresden, Germany
| | - Miguel A Caviedes
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, c/ Profesor García González, 2, 41012, Sevilla, Spain
| | - Ignacio D Rodriguez-Llorente
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, c/ Profesor García González, 2, 41012, Sevilla, Spain
| | - Brahim Oudra
- Laboratory of Biology and Biotechnology of Microorganisms, Environmental Microbiology and Toxicology Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, PO Box 2390, Marrakech, Morocco
| | - Eloísa Pajuelo
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, c/ Profesor García González, 2, 41012, Sevilla, Spain.
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22
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Downing S, Esterhuizen-Londt M, Grant Downing T. β-N-methylamino-L-alanine (BMAA) metabolism in the aquatic macrophyte Ceratophyllum demersum. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 120:88-92. [PMID: 26036420 DOI: 10.1016/j.ecoenv.2015.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 05/13/2015] [Accepted: 05/14/2015] [Indexed: 06/04/2023]
Abstract
The cyanobacterial neurotoxin, β-N-methylamino-l-alanine (BMAA) bioaccumulates and biomagnifies within the environment. However, most reports on the environmental presence of BMAA focus on the presence of BMAA in animals rather than in plants. Various laboratory studies have reported that this neurotoxin, implicated in neurodegenerative disease, is rapidly taken up by various aquatic and terrestrial plants, including crop plants. In this study the metabolism of BMAA in the aquatic macrophyte, Ceratophyllum demersum, was investigated using stable isotopically labelled BMAA. Data show that the toxin is rapidly removed from the environment by the plant. However, during depuration cellular BMAA concentrations decrease considerably, without excretion of the toxin back into the environment and without catabolism of BMAA, evidenced by the absence of label transfer to other amino acids. This strongly suggests that BMAA is metabolised via covalent modification and sequestered inside the plant as a BMAA-derivative. This modification may be reversed in humans following consumption of BMAA-containing plant material. These data therefore impact on the assessment of the risk of human exposure to this neurotoxin.
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Affiliation(s)
- Simoné Downing
- Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, PO Box 77 000, Port Elizabeth 6031, South Africa.
| | - Maranda Esterhuizen-Londt
- Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, PO Box 77 000, Port Elizabeth 6031, South Africa.
| | - Timothy Grant Downing
- Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, PO Box 77 000, Port Elizabeth 6031, South Africa; The Institute for Ethnomedicine, 240E Deloney Ave, Jackson, WY 83001, United States of America.
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