1
|
Santiago-Maldonado X, Rodríguez-Martínez JA, López L, Cunci L, Bayro M, Nicolau E. Selection, characterization, and biosensing applications of DNA aptamers targeting cyanotoxin BMAA. RSC Adv 2024; 14:13787-13800. [PMID: 38681844 PMCID: PMC11046380 DOI: 10.1039/d4ra02384f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024] Open
Abstract
Scientists have established a connection between environmental exposure to toxins like β-N-methylamino-l-alanine (BMAA) and a heightened risk of neurodegenerative disorders. BMAA is a byproduct from certain strains of cyanobacteria that are present in ecosystems worldwide and is renowned for its bioaccumulation and biomagnification in seafood. The sensitivity, selectivity, and reproducibility of the current analytical techniques are insufficient to support efforts regarding food safety and environment monitoring adequately. This work outlines the in vitro selection of BMAA-specific DNA aptamers via the systematic evolution of ligands through exponential enrichment (SELEX). Screening and characterization of the full-length aptamers was achieved using the SYBR Green (SG) fluorescence displacement assay. Aptamers BMAA_159 and BMAA_165 showed the highest binding affinities, with dissociation constants (Kd) of 2.2 ± 0.1 μM and 0.32 ± 0.02 μM, respectively. After truncation, the binding affinity was confirmed using a BMAA-conjugated fluorescence assay. The Kd values for BMAA_159_min and BMAA_165_min were 6 ± 1 μM and 0.63 ± 0.02 μM, respectively. Alterations in the amino proton region studied using solution nuclear magnetic resonance (NMR) provided further evidence of aptamer-target binding. Additionally, circular dichroism (CD) spectroscopy revealed that BMAA_165_min forms hybrid G-quadruplex (G4) structures. Finally, BMAA_165_min was used in the development of an electrochemical aptamer-based (EAB) sensor that accomplished sensitive and selective detection of BMAA with a limit of detection (LOD) of 1.13 ± 0.02 pM.
Collapse
Affiliation(s)
- Xaimara Santiago-Maldonado
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
| | | | - Luis López
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
| | - Lisandro Cunci
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
| | - Marvin Bayro
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
- Molecular Science Research Center, University of Puerto Rico San Juan 00931-3346 USA
| | - Eduardo Nicolau
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
- Molecular Science Research Center, University of Puerto Rico San Juan 00931-3346 USA
| |
Collapse
|
2
|
Sandhu PK, Solonenka JT, Murch SJ. Neurotoxic non-protein amino acids in commercially harvested Lobsters (Homarus americanus H. Milne-Edwards). Sci Rep 2024; 14:8017. [PMID: 38580836 PMCID: PMC10997655 DOI: 10.1038/s41598-024-58778-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/03/2024] [Indexed: 04/07/2024] Open
Abstract
Cyanobacteria produce neurotoxic non-protein amino acids (NPAAs) that accumulate in ecosystems and food webs. American lobsters (Homarus americanus H. Milne-Edwards) are one of the most valuable seafood industries in Canada with exports valued at > $2 billion. Two previous studies have assessed the occurrence of β-N-methylamino-L-alanine (BMAA) in a small number of lobster tissues but a complete study has not previously been undertaken. We measured NPAAs in eyeballs, brain, legs, claws, tails, and eggs of 4 lobsters per year for the 2021 and 2022 harvests. Our study included 4 male and 4 female lobsters. We detected BMAA and its isomers, N-(2-aminoethyl)glycine (AEG), 2,4-diaminobutyric acid (DAB) and β-aminomethyl-L-alanine (BAMA) by a fully validated reverse phase chromatography-tandem mass spectrometry method. We quantified BMAA, DAB, AEG and BAMA in all of the lobster tissues. Our quantification data varied by individual lobster, sex and collection year. Significantly more BMAA was quantified in lobsters harvested in 2021 than 2022. Interestingly, more BAMA was quantified in lobsters harvested in 2022 than 2021. Monitoring of lobster harvests for cyanobacterial neurotoxins when harmful algal bloom events occur could mitigate risks to human health.
Collapse
Affiliation(s)
- Pawanjit K Sandhu
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC, V1V 1V7, Canada
| | - Julia T Solonenka
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC, V1V 1V7, Canada
| | - Susan J Murch
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC, V1V 1V7, Canada.
| |
Collapse
|
3
|
Bishop SL, Solonenka JT, Giebelhaus RT, Bakker DTR, Li ITS, Murch SJ. Microbial Diversity Impacts Non-Protein Amino Acid Production in Cyanobacterial Bloom Cultures Collected from Lake Winnipeg. Toxins (Basel) 2024; 16:169. [PMID: 38668594 PMCID: PMC11053616 DOI: 10.3390/toxins16040169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/10/2024] [Accepted: 03/20/2024] [Indexed: 04/29/2024] Open
Abstract
Lake Winnipeg in Manitoba, Canada is heavily impacted by harmful algal blooms that contain non-protein amino acids (NPAAs) produced by cyanobacteria: N-(2-aminoethyl)glycine (AEG), β-aminomethyl-L-alanine (BAMA), β-N-methylamino-L-alanine (BMAA), and 2,4-diaminobutyric acid (DAB). Our objective was to investigate the impact of microbial diversity on NPAA production by cyanobacteria using semi-purified crude cyanobacterial cultures established from field samples collected by the Lake Winnipeg Research Consortium between 2016 and 2021. NPAAs were detected and quantified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) using validated analytical methods, while Shannon and Simpson alpha diversity scores were determined from 16S rRNA metagenomic sequences. Alpha diversity in isolate cultures was significantly decreased compared to crude cyanobacterial cultures (p < 0.001), indicating successful semi-purification. BMAA and AEG concentrations were higher in crude compared to isolate cultures (p < 0.0001), and AEG concentrations were correlated to the alpha diversity in cultures (r = 0.554; p < 0.0001). BAMA concentrations were increased in isolate cultures (p < 0.05), while DAB concentrations were similar in crude and isolate cultures. These results demonstrate that microbial community complexity impacts NPAA production by cyanobacteria and related organisms.
Collapse
Affiliation(s)
- Stephanie L. Bishop
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC V1V 1V7, Canada; (J.T.S.); (R.T.G.); (D.T.R.B.); (I.T.S.L.); (S.J.M.)
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Julia T. Solonenka
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC V1V 1V7, Canada; (J.T.S.); (R.T.G.); (D.T.R.B.); (I.T.S.L.); (S.J.M.)
| | - Ryland T. Giebelhaus
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC V1V 1V7, Canada; (J.T.S.); (R.T.G.); (D.T.R.B.); (I.T.S.L.); (S.J.M.)
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2N4, Canada
- The Metabolomics Innovation Centre, Edmonton, AB T6G 2N4, Canada
| | - David T. R. Bakker
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC V1V 1V7, Canada; (J.T.S.); (R.T.G.); (D.T.R.B.); (I.T.S.L.); (S.J.M.)
| | - Isaac T. S. Li
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC V1V 1V7, Canada; (J.T.S.); (R.T.G.); (D.T.R.B.); (I.T.S.L.); (S.J.M.)
| | - Susan J. Murch
- Department of Chemistry, University of British Columbia, Syilx Okanagan Nation Territory, Kelowna, BC V1V 1V7, Canada; (J.T.S.); (R.T.G.); (D.T.R.B.); (I.T.S.L.); (S.J.M.)
| |
Collapse
|
4
|
Lee A, Henderson R, Aylward J, McCombe P. Gut Symptoms, Gut Dysbiosis and Gut-Derived Toxins in ALS. Int J Mol Sci 2024; 25:1871. [PMID: 38339149 PMCID: PMC10856138 DOI: 10.3390/ijms25031871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024] Open
Abstract
Many pathogenetic mechanisms have been proposed for amyotrophic lateral sclerosis (ALS). Recently, there have been emerging suggestions of a possible role for the gut microbiota. Gut microbiota have a range of functions and could influence ALS by several mechanisms. Here, we review the possible role of gut-derived neurotoxins/excitotoxins. We review the evidence of gut symptoms and gut dysbiosis in ALS. We then examine a possible role for gut-derived toxins by reviewing the evidence that these molecules are toxic to the central nervous system, evidence of their association with ALS, the existence of biochemical pathways by which these molecules could be produced by the gut microbiota and existence of mechanisms of transport from the gut to the blood and brain. We then present evidence that there are increased levels of these toxins in the blood of some ALS patients. We review the effects of therapies that attempt to alter the gut microbiota or ameliorate the biochemical effects of gut toxins. It is possible that gut dysbiosis contributes to elevated levels of toxins and that these could potentially contribute to ALS pathogenesis, but more work is required.
Collapse
Affiliation(s)
- Aven Lee
- Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia; (R.H.); (P.M.)
| | - Robert Henderson
- Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia; (R.H.); (P.M.)
- Department of Neurology, Royal Brisbane & Women’s Hospital, Brisbane, QLD 4029, Australia
- Wesley Research Institute, The Wesley Hospital, Auchenflower, QLD 4066, Australia;
| | - James Aylward
- Wesley Research Institute, The Wesley Hospital, Auchenflower, QLD 4066, Australia;
| | - Pamela McCombe
- Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia; (R.H.); (P.M.)
- Department of Neurology, Royal Brisbane & Women’s Hospital, Brisbane, QLD 4029, Australia
- Wesley Research Institute, The Wesley Hospital, Auchenflower, QLD 4066, Australia;
| |
Collapse
|
5
|
Metcalf JS, Banack SA, Wyatt PB, Nunn PB, Cox PA. A Direct Analysis of β- N-methylamino-l-alanine Enantiomers and Isomers and Its Application to Cyanobacteria and Marine Mollusks. Toxins (Basel) 2023; 15:639. [PMID: 37999501 PMCID: PMC10674937 DOI: 10.3390/toxins15110639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/11/2023] [Accepted: 10/18/2023] [Indexed: 11/25/2023] Open
Abstract
Of the wide variety of toxic compounds produced by cyanobacteria, the neurotoxic amino acid β-N-methylamino-l-alanine (BMAA) has attracted attention as a result of its association with chronic human neurodegenerative diseases such as ALS and Alzheimer's. Consequently, specific detection methods are required to assess the presence of BMAA and its isomers in environmental and clinical materials, including cyanobacteria and mollusks. Although the separation of isomers such as β-amino-N-methylalanine (BAMA), N-(2-aminoethyl)glycine (AEG) and 2,4-diaminobutyric acid (DAB) from BMAA has been demonstrated during routine analysis, a further compounding factor is the potential presence of enantiomers for some of these isomers. Current analytical methods for BMAA mostly do not discriminate between enantiomers, and the chiral configuration of BMAA in cyanobacteria is still largely unexplored. To understand the potential for the occurrence of D-BMAA in cyanobacteria, a chiral UPLC-MS/MS method was developed to separate BMAA enantiomers and isomers and to determine the enantiomeric configuration of endogenous free BMAA in a marine Lyngbya mat and two mussel reference materials. After extraction, purification and derivatization with N-(4-nitrophenoxycarbonyl)-l-phenylalanine 2-methoxyethyl ester ((S)-NIFE), both L- and D-BMAA were identified as free amino acids in cyanobacterial materials, whereas only L-BMAA was identified in mussel tissues. The finding of D-BMAA in biological environmental materials raises questions concerning the source and role of BMAA enantiomers in neurological disease.
Collapse
Affiliation(s)
- James S. Metcalf
- Brain Chemistry Labs, Box 3464, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA
| | - Sandra Anne Banack
- Brain Chemistry Labs, Box 3464, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
| | - Peter B. Wyatt
- The School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (P.B.W.); (P.B.N.)
| | - Peter B. Nunn
- The School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (P.B.W.); (P.B.N.)
| | - Paul A. Cox
- Brain Chemistry Labs, Box 3464, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
| |
Collapse
|
6
|
Pravadali-Cekic S, Vojvodic A, Violi JP, Mitrovic SM, Rodgers KJ, Bishop DP. Simultaneous Analysis of Cyanotoxins β-N-methylamino-L-alanine (BMAA) and Microcystins-RR, -LR, and -YR Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Molecules 2023; 28:6733. [PMID: 37764509 PMCID: PMC10537148 DOI: 10.3390/molecules28186733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
β-N-methylamino-L-alanine (BMAA) and its isomers, 2,4-diaminobutyric acid (2,4-DAB) and N-(2-aminoethyl)-glycine (AEG), along with microcystins (MCs)-RR, -LR, and -YR (the major MC congeners), are cyanotoxins that can cause detrimental health and environmental impacts during toxic blooms. Currently, there are no reverse-phase (RP) LC-MS/MS methods for the simultaneous detection and quantification of BMAA, its isomers, and the major MCs in a single analysis; therefore, multiple analyses are required to assess the toxic load of a sample. Here, we present a newly developed and validated method for the detection and quantification of BMAA, 2,4-DAB, AEG, MC-LR, MC-RR, and MC-YR using RP LC-MS/MS. Method validation was performed, assessing linearity (r2 > 0.996), accuracy (>90% recovery for spiked samples), precision (7% relative standard deviation), and limits of detection (LODs) and quantification (LOQs) (ranging from 0.13 to 1.38 ng mL-1). The application of this combined cyanotoxin analysis on a culture of Microcystis aeruginosa resulted in the simultaneous detection of 2,4-DAB (0.249 ng mg-1 dry weight (DW)) and MC-YR (4828 ng mg-1 DW). This study provides a unified method for the quantitative analysis of BMAA, its isomers, and three MC congeners in natural environmental samples.
Collapse
Affiliation(s)
- Sercan Pravadali-Cekic
- Hyphenated Mass Spectrometry Laboratory (HyMaS), University of Technology Sydney, Sydney, NSW 2007, Australia; (S.P.-C.)
| | - Aleksandar Vojvodic
- Hyphenated Mass Spectrometry Laboratory (HyMaS), University of Technology Sydney, Sydney, NSW 2007, Australia; (S.P.-C.)
| | - Jake P. Violi
- School of Chemistry, University of New South Wales, Sydney, NSW 2033, Australia;
| | - Simon M. Mitrovic
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (S.M.M.); (K.J.R.)
| | - Kenneth J. Rodgers
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (S.M.M.); (K.J.R.)
| | - David P. Bishop
- Hyphenated Mass Spectrometry Laboratory (HyMaS), University of Technology Sydney, Sydney, NSW 2007, Australia; (S.P.-C.)
| |
Collapse
|
7
|
Wang ZQ, Yang Y, Zhang JY, Zeng X, Zhang CC. Global translational control by the transcriptional repressor TrcR in the filamentous cyanobacterium Anabaena sp. PCC 7120. Commun Biol 2023; 6:643. [PMID: 37322092 PMCID: PMC10272220 DOI: 10.1038/s42003-023-05012-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/02/2023] [Indexed: 06/17/2023] Open
Abstract
Transcriptional and translational regulations are important mechanisms for cell adaptation to environmental conditions. In addition to house-keeping tRNAs, the genome of the filamentous cyanobacterium Anabaena sp. strain PCC 7120 (Anabaena) has a long tRNA operon (trn operon) consisting of 26 genes present on a megaplasmid. The trn operon is repressed under standard culture conditions, but is activated under translational stress in the presence of antibiotics targeting translation. Using the toxic amino acid analog β-N-methylamino-L-alanine (BMAA) as a tool, we isolated and characterized several BMAA-resistance mutants from Anabaena, and identified one gene of unknown function, all0854, named as trcR, encoding a transcription factor belonging to the ribbon-helix-helix (RHH) family. We provide evidence that TrcR represses the expression of the trn operon and is thus the missing link between the trn operon and translational stress response. TrcR represses the expression of several other genes involved in translational control, and is required for maintaining translational fidelity. TrcR, as well as its binding sites, are highly conserved in cyanobacteria, and its functions represent an important mechanism for the coupling of the transcriptional and translational regulations in cyanobacteria.
Collapse
Affiliation(s)
- Zi-Qian Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
| | - Yiling Yang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China
| | - Ju-Yuan Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China
| | - Xiaoli Zeng
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China
| | - Cheng-Cai Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China.
- Institute AMU-WUT, Aix-Marseille Université and Wuhan University of Technology, Wuhan, Hubei, People's Republic of China.
| |
Collapse
|
8
|
Lopicic S, Svirčev Z, Palanački Malešević T, Kopitović A, Ivanovska A, Meriluoto J. Environmental Neurotoxin β- N-Methylamino-L-alanine (BMAA) as a Widely Occurring Putative Pathogenic Factor in Neurodegenerative Diseases. Microorganisms 2022; 10:2418. [PMID: 36557671 PMCID: PMC9781992 DOI: 10.3390/microorganisms10122418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
In the present review we have discussed the occurrence of β-N-methylamino-L-alanine (BMAA) and its natural isomers, and the organisms and sample types in which the toxin(s) have been detected. Further, the review discusses general pathogenic mechanisms of neurodegenerative diseases, and how modes of action of BMAA fit in those mechanisms. The biogeography of BMAA occurrence presented here contributes to the planning of epidemiological research based on the geographical distribution of BMAA and human exposure. Analysis of BMAA mechanisms in relation to pathogenic processes of neurodegeneration is used to critically assess the potential significance of the amino acid as well as to identify gaps in our understanding. Taken together, these two approaches provide the basis for the discussion on the potential role of BMAA as a secondary factor in neurodegenerative diseases, the rationale for further research and possible directions the research can take, which are outlined in the conclusions.
Collapse
Affiliation(s)
- Srdjan Lopicic
- Faculty of Medicine, University of Belgrade, Dr Subotića Starijeg 8, 11000 Belgrade, Serbia
| | - Zorica Svirčev
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
- Faculty of Science and Engineering, Biochemistry, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
| | - Tamara Palanački Malešević
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
| | - Aleksandar Kopitović
- Faculty of Medicine, University of Novi Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia
| | - Aleksandra Ivanovska
- Innovation Center of the Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
| | - Jussi Meriluoto
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
- Faculty of Science and Engineering, Biochemistry, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
| |
Collapse
|
9
|
Emmons RV, Karaj E, Cudjoe E, Bell DS, Tillekeratne LV, Gionfriddo E. Leveraging multi-mode microextraction and liquid chromatography stationary phases for quantitative analysis of neurotoxin β-N-methylamino-L-alanine and other non-proteinogenic amino acids. J Chromatogr A 2022; 1685:463636. [DOI: 10.1016/j.chroma.2022.463636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/15/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022]
|
10
|
Koksharova OA, Safronova NA. Non-Proteinogenic Amino Acid β-N-Methylamino-L-Alanine (BMAA): Bioactivity and Ecological Significance. Toxins (Basel) 2022; 14:539. [PMID: 36006201 PMCID: PMC9414260 DOI: 10.3390/toxins14080539] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/28/2022] [Accepted: 08/04/2022] [Indexed: 11/21/2022] Open
Abstract
Research interest in a non-protein amino acid β-N-methylamino-L-alanine (BMAA) arose due to the discovery of a connection between exposure to BMAA and the occurrence of neurodegenerative diseases. Previous reviews on this topic either considered BMAA as a risk factor for neurodegenerative diseases or focused on the problems of detecting BMAA in various environmental samples. Our review is devoted to a wide range of fundamental biological problems related to BMAA, including the molecular mechanisms of biological activity of BMAA and the complex relationships between producers of BMAA and the environment in various natural ecosystems. At the beginning, we briefly recall the most important facts about the producers of BMAA (cyanobacteria, microalgae, and bacteria), the pathways of BMAA biosynthesis, and reliable methods of identification of BMAA. The main distinctive feature of our review is a detailed examination of the molecular mechanisms underlying the toxicity of BMAA to living cells. A brand new aspect, not previously discussed in any reviews, is the effect of BMAA on cyanobacterial cells. These recent studies, conducted using transcriptomics and proteomics, revealed potent regulatory effects of BMAA on the basic metabolism and cell development of these ancient photoautotrophic prokaryotes. Exogenous BMAA strongly influences cell differentiation and primary metabolic processes in cyanobacteria, such as nitrogen fixation, photosynthesis, carbon fixation, and various biosynthetic processes involving 2-oxoglutarate and glutamate. Cyanobacteria were found to be more sensitive to exogenous BMAA under nitrogen-limited growth conditions. We suggest a hypothesis that this toxic diaminoacid can be used by phytoplankton organisms as a possible allelopathic tool for controlling the population of cyanobacterial cells during a period of intense competition for nitrogen and other resources in various ecosystems.
Collapse
Affiliation(s)
- Olga A. Koksharova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- Institute of Molecular Genetics of National Research Center “Kurchatov Institute”, Kurchatov Square, 2, 123182 Moscow, Russia
| | - Nina A. Safronova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| |
Collapse
|
11
|
Zhao P, Qiu J, Li A, Yan G, Li M, Ji Y. Matrix Effect of Diverse Biological Samples Extracted with Different Extraction Ratios on the Detection of β-N-Methylamino-L-Alanine by Two Common LC-MS/MS Analysis Methods. Toxins (Basel) 2022; 14:toxins14060387. [PMID: 35737048 PMCID: PMC9230712 DOI: 10.3390/toxins14060387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 05/27/2022] [Accepted: 05/31/2022] [Indexed: 11/16/2022] Open
Abstract
Neurotoxin β-N-methylamino-L-alanine (BMAA) is hypothesized as an important pathogenic factor for neurodegenerative diseases such as amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS-PDC). Comparative study on the accuracy of BMAA analyzed by the regular LC-MS/MS methods is still limited for different biological matrices. In this study, a free-BMAA sample of cyanobacterium and BMAA-containing positive samples of diatom, mussel, scallop, and oyster were extracted with varied extraction ratios (ER) ranging from 1:20 to 1:2000. These extracts were then purified by MCX cartridges. After SPE purification, these different biological samples were analyzed by two common LC-MS/MS analysis methods, a direct analysis without derivatization by a hydrophilic interaction liquid chromatography (HILIC)-MS/MS and pre-column 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization combined with a C18 column. The results suggested that the recoveries of BMAA spiked in the cyanobacterial sample were close to 100% in the total soluble form extracts with the ER of 1:100 (g/mL) and the precipitated bound form extracts with the ER of 1:500. The recommended ER for the precipitated bound form of BMAA in diatoms and the total soluble form of BMAA in mollusks are 1:500 and 1:50, respectively. The quantitative results determined by the AQC derivatization method were lower than those determined by the direct analysis of the HILIC method in diatom and mollusk samples. The results of the HILIC method without the derivatization process were closer to the true value of BMAA in cyanobacteria. This work contributes to the performance of the solid-phase extraction (SPE) purification protocol and the accuracy of BMAA analysis by LC-MS/MS in diverse biological samples.
Collapse
Affiliation(s)
- Peng Zhao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; (P.Z.); (J.Q.); (G.Y.); (M.L.); (Y.J.)
| | - Jiangbing Qiu
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; (P.Z.); (J.Q.); (G.Y.); (M.L.); (Y.J.)
- Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Aifeng Li
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; (P.Z.); (J.Q.); (G.Y.); (M.L.); (Y.J.)
- Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
- Correspondence: ; Tel.: +86-532-66781935
| | - Guowang Yan
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; (P.Z.); (J.Q.); (G.Y.); (M.L.); (Y.J.)
| | - Min Li
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; (P.Z.); (J.Q.); (G.Y.); (M.L.); (Y.J.)
| | - Ying Ji
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; (P.Z.); (J.Q.); (G.Y.); (M.L.); (Y.J.)
| |
Collapse
|
12
|
Courtier A, Potheret D, Giannoni P. Environmental bacteria as triggers to brain disease: Possible mechanisms of toxicity and associated human risk. Life Sci 2022; 304:120689. [DOI: 10.1016/j.lfs.2022.120689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/11/2022] [Accepted: 06/01/2022] [Indexed: 11/24/2022]
|
13
|
Abbes S, Vo Duy S, Munoz G, Dinh QT, Simon DF, Husk B, Baulch HM, Vinçon-Leite B, Fortin N, Greer CW, Larsen ML, Venkiteswaran JJ, Martínez Jerónimo FF, Giani A, Lowe CD, Tromas N, Sauvé S. Occurrence of BMAA Isomers in Bloom-Impacted Lakes and Reservoirs of Brazil, Canada, France, Mexico, and the United Kingdom. Toxins (Basel) 2022; 14:251. [PMID: 35448860 PMCID: PMC9026818 DOI: 10.3390/toxins14040251] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/26/2022] [Accepted: 03/30/2022] [Indexed: 11/21/2022] Open
Abstract
The neurotoxic alkaloid β-N-methyl-amino-l-alanine (BMAA) and related isomers, including N-(2-aminoethyl glycine) (AEG), β-amino-N-methyl alanine (BAMA), and 2,4-diaminobutyric acid (DAB), have been reported previously in cyanobacterial samples. However, there are conflicting reports regarding their occurrence in surface waters. In this study, we evaluated the impact of amending lake water samples with trichloroacetic acid (0.1 M TCA) on the detection of BMAA isomers, compared with pre-existing protocols. A sensitive instrumental method was enlisted for the survey, with limits of detection in the range of 5−10 ng L−1. Higher detection rates and significantly greater levels (paired Wilcoxon’s signed-rank tests, p < 0.001) of BMAA isomers were observed in TCA-amended samples (method B) compared to samples without TCA (method A). The overall range of B/A ratios was 0.67−8.25 for AEG (up to +725%) and 0.69−15.5 for DAB (up to +1450%), with absolute concentration increases in TCA-amended samples of up to +15,000 ng L−1 for AEG and +650 ng L−1 for DAB. We also documented the trends in the occurrence of BMAA isomers for a large breadth of field-collected lakes from Brazil, Canada, France, Mexico, and the United Kingdom. Data gathered during this overarching campaign (overall, n = 390 within 45 lake sampling sites) indicated frequent detections of AEG and DAB isomers, with detection rates of 30% and 43% and maximum levels of 19,000 ng L−1 and 1100 ng L−1, respectively. In contrast, BAMA was found in less than 8% of the water samples, and BMAA was not found in any sample. These results support the analyses of free-living cyanobacteria, wherein BMAA was often reported at concentrations of 2−4 orders of magnitude lower than AEG and DAB. Seasonal measurements conducted at two bloom-impacted lakes indicated limited correlations of BMAA isomers with total microcystins or chlorophyll-a, which deserves further investigation.
Collapse
Affiliation(s)
- Safa Abbes
- Department of Chemistry, Université de Montréal, Montréal, QC H2V 0B3, Canada; (S.A.); (S.V.D.); (G.M.); (Q.T.D.); (D.F.S.)
| | - Sung Vo Duy
- Department of Chemistry, Université de Montréal, Montréal, QC H2V 0B3, Canada; (S.A.); (S.V.D.); (G.M.); (Q.T.D.); (D.F.S.)
| | - Gabriel Munoz
- Department of Chemistry, Université de Montréal, Montréal, QC H2V 0B3, Canada; (S.A.); (S.V.D.); (G.M.); (Q.T.D.); (D.F.S.)
| | - Quoc Tuc Dinh
- Department of Chemistry, Université de Montréal, Montréal, QC H2V 0B3, Canada; (S.A.); (S.V.D.); (G.M.); (Q.T.D.); (D.F.S.)
| | - Dana F. Simon
- Department of Chemistry, Université de Montréal, Montréal, QC H2V 0B3, Canada; (S.A.); (S.V.D.); (G.M.); (Q.T.D.); (D.F.S.)
| | - Barry Husk
- BlueLeaf Inc., Drummondville, QC J2B 5E9, Canada;
| | - Helen M. Baulch
- Global Institute for Water Security, University of Saskatchewan, Saskatoon, SK S7N 3H5, Canada;
| | | | - Nathalie Fortin
- National Research Council Canada, Energy, Mining, and Environment, Montréal, QC H4P 2R2, Canada; (N.F.); (C.W.G.)
| | - Charles W. Greer
- National Research Council Canada, Energy, Mining, and Environment, Montréal, QC H4P 2R2, Canada; (N.F.); (C.W.G.)
| | - Megan L. Larsen
- Faculty of Science, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada; (M.L.L.); (J.J.V.)
| | - Jason J. Venkiteswaran
- Faculty of Science, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada; (M.L.L.); (J.J.V.)
| | | | - Alessandra Giani
- Department of Botany, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil;
| | - Chris D. Lowe
- Centre for Ecology and Conservation, University of Exeter, Exeter TR10 9FE, UK;
| | - Nicolas Tromas
- Department of Biological Sciences, Université de Montréal, Montréal, QC H2V 0B3, Canada;
| | - Sébastien Sauvé
- Department of Chemistry, Université de Montréal, Montréal, QC H2V 0B3, Canada; (S.A.); (S.V.D.); (G.M.); (Q.T.D.); (D.F.S.)
| |
Collapse
|
14
|
Cyanotoxins and the Nervous System. Toxins (Basel) 2021; 13:toxins13090660. [PMID: 34564664 PMCID: PMC8472772 DOI: 10.3390/toxins13090660] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/31/2021] [Accepted: 09/09/2021] [Indexed: 11/16/2022] Open
Abstract
Cyanobacteria are capable of producing a wide range of bioactive compounds with many considered to be toxins. Although there are a number of toxicological outcomes with respect to cyanobacterial exposure, this review aims to examine those which affect the central nervous system (CNS) or have neurotoxicological properties. Such exposures can be acute or chronic, and we detail issues concerning CNS entry, detection and remediation. Exposure can occur through a variety of media but, increasingly, exposure through air via inhalation may have greater significance and requires further investigation. Even though cyanobacterial toxins have traditionally been classified based on their primary mode of toxicity, increasing evidence suggests that some also possess neurotoxic properties and include known cyanotoxins and unknown compounds. Furthermore, chronic long-term exposure to these compounds is increasingly being identified as adversely affecting human health.
Collapse
|
15
|
Wang C, Yan C, Qiu J, Liu C, Yan Y, Ji Y, Wang G, Chen H, Li Y, Li A. Food web biomagnification of the neurotoxin β-N-methylamino-L-alanine in a diatom-dominated marine ecosystem in China. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:124217. [PMID: 33129020 DOI: 10.1016/j.jhazmat.2020.124217] [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: 08/22/2020] [Revised: 09/25/2020] [Accepted: 10/05/2020] [Indexed: 06/11/2023]
Abstract
The neurotoxin β-N-methylamino-L-alanine (BMAA) reported in some cyanobacteria and eukaryote microalgae is a cause of concern due to its potential risk of human neurodegenerative diseases. Here, BMAA distribution in phytoplankton, zooplankton, and other marine organisms was investigated in Jiaozhou Bay, China, a diatom-dominated marine ecosystem, during four seasons in 2019. Results showed that BMAA was biomagnified in the food web from phytoplankton to higher trophic levels. Trophic magnification factors (TMFs) for zooplankton, bivalve mollusks, carnivorous crustaceans and carnivorous gastropod mollusks were ca. 4.58, 30.1, 42.5, and 74.4, respectively. Putative identification of β-amino-N-methylalanine (BAMA), an isomer of BMAA, was frequently detected in phytoplankton samples. A total of 56 diatom strains of the genera Pseudo-nitzschia, Thalassiosira, Chaetoceros, Planktoniella, and Minidiscus isolated from the Chinese coast were cultured in the laboratory, among which 21 strains contained BMAA mainly in precipitated bound form at toxin concentrations ranging from 0.11 to 3.95 µg/g dry weight. Only 2,4-diaminobutyric acid (DAB) but not BMAA or BAMA was detected in seven species of bacteria isolated from the gut of gastropod Neverita didyma, suggesting that this benthic vector of BMAA may have accumulated this compound via trophic transfer.
Collapse
Affiliation(s)
- Chao Wang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Chen Yan
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Jiangbing Qiu
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Chao Liu
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Yeju Yan
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Ying Ji
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Guixiang Wang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Hongju Chen
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China
| | - Yang Li
- Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou 510631, China
| | - Aifeng Li
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China.
| |
Collapse
|
16
|
Ra D, Sa B, Sl B, Js M, Sj M, DA D, Ew S, O K, Eb B, Ad C, Vx T, Gg G, Pa C, Dc M, Wg B. Is Exposure to BMAA a Risk Factor for Neurodegenerative Diseases? A Response to a Critical Review of the BMAA Hypothesis. Neurotox Res 2021; 39:81-106. [PMID: 33547590 PMCID: PMC7904546 DOI: 10.1007/s12640-020-00302-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 12/15/2022]
Abstract
In a literature survey, Chernoff et al. (2017) dismissed the hypothesis that chronic exposure to β-N-methylamino-L-alanine (BMAA) may be a risk factor for progressive neurodegenerative disease. They question the growing scientific literature that suggests the following: (1) BMAA exposure causes ALS/PDC among the indigenous Chamorro people of Guam; (2) Guamanian ALS/PDC shares clinical and neuropathological features with Alzheimer's disease, Parkinson's disease, and ALS; (3) one possible mechanism for protein misfolds is misincorporation of BMAA into proteins as a substitute for L-serine; and (4) chronic exposure to BMAA through diet or environmental exposures to cyanobacterial blooms can cause neurodegenerative disease. We here identify multiple errors in their critique including the following: (1) their review selectively cites the published literature; (2) the authors reported favorably on HILIC methods of BMAA detection while the literature shows significant matrix effects and peak coelution in HILIC that may prevent detection and quantification of BMAA in cyanobacteria; (3) the authors build alternative arguments to the BMAA hypothesis, rather than explain the published literature which, to date, has been unable to refute the BMAA hypothesis; and (4) the authors erroneously attribute methods to incorrect studies, indicative of a failure to carefully consider all relevant publications. The lack of attention to BMAA research begins with the review's title which incorrectly refers to BMAA as a "non-essential" amino acid. Research regarding chronic exposure to BMAA as a cause of human neurodegenerative diseases is emerging and requires additional resources, validation, and research. Here, we propose strategies for improvement in the execution and reporting of analytical methods and the need for additional and well-executed inter-lab comparisons for BMAA quantitation. We emphasize the need for optimization and validation of analytical methods to ensure that they are fit-for-purpose. Although there remain gaps in the literature, an increasingly large body of data from multiple independent labs using orthogonal methods provides increasing evidence that chronic exposure to BMAA may be a risk factor for neurological illness.
Collapse
Affiliation(s)
- Dunlop Ra
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA.
| | - Banack Sa
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Bishop Sl
- Lewis Research Group, Faculty of Science, University of Calgary, Alberta, Canada
| | - Metcalf Js
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Murch Sj
- Department of Chemistry, University of British Columbia, Kelowna, BC, Canada
| | - Davis DA
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Stommel Ew
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Karlsson O
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Brittebo Eb
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | | | - Tan Vx
- Department of Biological Sciences, Macquarie University Centre for Motor Neuron Disease Research, Macquarie University, Ryde, Australia
| | - Guillemin Gg
- Department of Biological Sciences, Macquarie University Centre for Motor Neuron Disease Research, Macquarie University, Ryde, Australia
| | - Cox Pa
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Mash Dc
- Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Bradley Wg
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
| |
Collapse
|
17
|
Cox PA. BMAA, Neurodegeneration, and Neuroprotection. Neurotox Res 2020; 39:1-5. [PMID: 33196951 DOI: 10.1007/s12640-020-00303-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 12/29/2022]
Abstract
In this volume, studies springing from a BMAA symposium held in Salt Lake City, Utah, in April 2019 are presented. Although most studies of neurotoxicity consider the effects of BMAA as an isolated molecule, it is now known that environmental exposures can be to a combination of BMAA-related molecules, including enantiomers, isomers, other co-occurring cyanotoxins, and BMAA carbamates. Within the body, BMAA may exist in equilibrium with α- and β-carbamates formed in the presence of bicarbonate. BMAA and its isomers 2,4-DAB and AEG, accumulate over decades in biocrusts and persist at depths in soil profiles of the Gulf deserts. In Florida, releases of cyanobacterially ladened water from Lake Okeechobee can extend into coastal environments where diatoms and possibly dinoflagellates also produce BMAA and isomers in addition to brevetoxins. Along the African Lake Chad, neurotoxic risks from consumption of dried cyanobacterial cakes may, however, be outweighed by their amino acid addition to otherwise protein-deficient diets. Discrepancies in the detection and quantification of BMAA from different laboratories likely originate in the use of different analytical methods. C-18 columns, used to study derivatized BMAA, can efficiently separate BMAA from its isomers in validated methods, while validation is not possible for HILIC columns in the study of underivatized BMAA, since they do not adequately separate BMAA from its isomer BAMA. The presence of BMAA dimers, metal adducts, and carbamates may result in underestimation of BMAA by mass spectrometry. BMAA research led to the identification of the dietary amino acid L-serine as a neuroprotective molecule. In animal and clinical trials, L-serine appears to slow neurodegeneration, although the modes of action are still under study. Based on zebra fish sensitivity to platinum-based chemotherapeutic agents, investigators have found that L-serine reduces reactive oxygen species (ROS) but does not protect auditory hybridoma cells from cisplatin. Another possible mode of action of L-serine, induction of autophagic-lysosomal enzymes, is also being explored. The hypothesis that cyanobacterial exposures in general, and chronic exposures to BMAA in particular, may prove to be risk factors for neurodegenerative illnesses has not been without critics. Emerging from the symposium, a multi-authored response to one such critical paper appears in this collection of articles. Instead of waiting until there is a conclusive proof of risk, the adoption of the "precautionary default principle," proposed by Ingvar Brandt and his colleagues in Sweden, is suggested. Avoidance of exposures to cyanobacterial blooms and other sources of BMAA is suggested, until further research indicates such precautions to be unnecessary.
Collapse
Affiliation(s)
- Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY, 83001, USA.
| |
Collapse
|
18
|
The Proposed Neurotoxin β- N-Methylamino-l-Alanine (BMAA) Is Taken up through Amino-Acid Transport Systems in the Cyanobacterium Anabaena PCC 7120. Toxins (Basel) 2020; 12:toxins12080518. [PMID: 32823543 PMCID: PMC7472364 DOI: 10.3390/toxins12080518] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/10/2020] [Accepted: 08/11/2020] [Indexed: 01/20/2023] Open
Abstract
Produced by cyanobacteria and some plants, BMAA is considered as an important environmental factor in the occurrence of some neurodegenerative diseases. Neither the underlying mechanism of its toxicity, nor its biosynthetic or metabolic pathway in cyanobacteria is understood. Interestingly, BMAA is found to be toxic to some cyanobacteria, making it possible to dissect the mechanism of BMAA metabolism by genetic approaches using these organisms. In this study, we used the cyanobacterium Anabaena PCC 7120 to isolate BMAA-resistant mutants. Following genomic sequencing, several mutations were mapped to two genes involved in amino acids transport, suggesting that BMAA was taken up through amino acid transporters. This conclusion was supported by the protective effect of several amino acids against BMAA toxicity. Furthermore, targeted inactivation of genes encoding different amino acid transport pathways conferred various levels of resistance to BMAA. One mutant inactivating all three major amino acid transport systems could no longer take up BMAA and gained full resistance to BMAA toxicity. Therefore, BMAA is a substrate of amino acid transporters, and cyanobacteria are interesting models for genetic analysis of BMAA transport and metabolism.
Collapse
|
19
|
Second Laboratory Validation of β-N-Methylamino-L-Alanine, N-(2aminoethyl)Glycine, and 2,4-Diaminobuytric Acid by Ultra-Performance Liquid Chromatography and Tandem Mass Spectrometry. Neurotox Res 2020; 39:107-116. [PMID: 32462275 DOI: 10.1007/s12640-020-00208-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/23/2020] [Accepted: 04/14/2020] [Indexed: 12/16/2022]
Abstract
The analysis of β-N-methylamino-L-alanine (BMAA) has been validated according to AOAC international standards by a single laboratory (Glover et al. 2015). Using the same validated method, we add a second laboratory validation optimizing for different equipment. Given publicized concerns about standardizing methods across laboratories and recent reviews indicating superior results using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate derivatization for the separation of BMAA and its isomers N-(2aminoethyl)glycine (AEG), and 2,4-diaminobuytric acid (DAB) (Bishop and Murch 2019), we add a second laboratory validation to this method demonstrating that the method is robust across laboratories using different equipment. Using the US Food and Drug Administration (FDA 2018) method for evaluating instrument parameters, we calculated a limit of detection (LOD) of 10 pg/ml for BMAA, AEG, and DAB and lower limits of quantification (LLOQ) of 37 pg/ml based on reagent blanks. In biological matrices, a higher LLOQ may be warranted for AEG and DAB. We demonstrate that the endogenous BMAA in mussel tissue can be lost by drying the hydrolyzed preparation and suggest sample preparation parameters be evaluated for robustness.
Collapse
|