1
|
Metcalf JS, Banack SA, Cox PA. Cyanotoxin Analysis of Air Samples from the Great Salt Lake. Toxins (Basel) 2023; 15:659. [PMID: 37999522 PMCID: PMC10675144 DOI: 10.3390/toxins15110659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
The Great Salt Lake in Utah is the largest saline lake in the Western hemisphere and one of the largest terminal lakes in the world. Situated at the eastern edge of the Great Basin, it is a remnant of the freshwater Lake Bonneville whose water level precipitously lowered about 12,000 years ago due to a natural break in Red Rock pass to the north. It contains a diverse assemblage of cyanobacteria which vary spatially dependent on salinity. In 1984, the waters of the Great Salt Lake occupied 8500 km2. Nearly four decades later, the waters occupy 2500 km2-a reduction in surface area of 71%. With predominantly westerly winds, there is a potential for the adjacent metropolitan residents to the east to be exposed to airborne cyanobacteria- and cyanotoxin-containing dust. During the summer and fall months of 2022, air and dried sediment samples were collected and assessed for the presence of BMAA which has been identified as a risk factor for ALS. Collection of air samples equivalent to a person breathing for 1 h resulted in BMAA and isomers being found in some air samples, along with their presence in exposed lakebed samples. There was no clear relationship between the presence of these toxins in airborne and adjacent lakebed samples, suggesting that airborne toxins may originate from diffuse rather than point sources. These findings confirm that continued low water levels in the Great Salt Lake may constitute an increasing health hazard for the 2.5 million inhabitants of communities along the Wasatch Front.
Collapse
Affiliation(s)
- James S. Metcalf
- Brain Chemistry Labs, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA
| | | | - Paul Alan Cox
- Brain Chemistry Labs, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
| |
Collapse
|
2
|
Garamszegi SP, Banack SA, Duque LL, Metcalf JS, Stommel EW, Cox PA, Davis DA. Detection of β-N-methylamino-l-alanine in postmortem olfactory bulbs of Alzheimer's disease patients using UHPLC-MS/MS: An autopsy case-series study. Toxicol Rep 2023; 10:87-96. [PMID: 36691605 PMCID: PMC9860447 DOI: 10.1016/j.toxrep.2023.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/21/2022] [Accepted: 01/05/2023] [Indexed: 01/08/2023] Open
Abstract
Introduction Cyanobacterial blooms produce toxins that may become aerosolized, increasing health risks through inhalation exposures. Health related effects on the lower respiratory tract caused by these toxins are becoming better understood. However, nasal exposures to cyanotoxins remain understudied, especially for those with neurotoxic potential. Here, we present a case series study evaluating exposure to β-N-methylamino-l-alanine (BMAA), a cyanobacterial toxin linked to neurodegenerative disease, in postmortem olfactory tissues of individuals with varying stages of Alzheimer's disease (AD). Methods Olfactory bulb (Ob) tissues were collected during autopsies performed between 2014 and 2017 from six South Florida brain donors (ages 47-78) with residences less than 140 m from a freshwater body. A triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) method validated according to peer AOAC International guidelines was used to detect BMAA and two BMAA isomers: 2,4-diaminobutyric acid (2,4-DAB) and N-(2-aminoethyl)glycine (AEG). Quantitative PCR was performed on the contralateral Ob to evaluate the relative expression of genes related to proinflammatory cytokines (IL-6 & IL-18), apoptotic pathways (CASP1 & BCL2), and mitochondrial stress (IRF1 & PINK1). Immunohistochemistry was also performed on the adjacent olfactory tract (Ot) to evaluate co-occurring neuropathology with BMAA tissue concentration. Results BMAA was detected in the Ob of all cases at a median concentration of 30.4 ng/g (Range <LLOQ - 488.4 ng/g). Structural isomers were also detected with median concentrations of 28.8 ng/g (AEG) and 103.6 ng/g (2,4-DAB). In addition, we found that cases with BMAA tissue concentrations above the <LLOQ also displayed increased expression of IL-6 (3.3-fold), CASP1 (1.7-fold), and IRF1 (1.6-fold). Reactive microglial, astrogliosis, myelinopathy, and neuronopathy of axonal processes in the Ot were also observed in cases with higher BMAA tissue concentrations. Conclusion Our study demonstrates that the cyanobacterial toxin BMAA can be detected in the olfactory pathway, a window to the brain, and its presence may increase the occurrence of proinflammatory cytokines, reactive glia, and toxicity to axonal processes. Further studies will be needed to evaluate BMAA's toxicity via this route of exposure and factors that increase susceptibility.
Collapse
Key Words
- 2,4-DAB, 2,4-diaminobutyric acid
- AD, Alzheimer's disease
- AEG, N-(2-aminoethyl)glycine
- ALS/PDC, Amyotrophic lateral sclerosis/ parkinsonism dementia complex
- BMAA, β-N-methylamino-l-alanine
- CBs, Cyanobacterial blooms
- Cyanobacteria
- Cyanotoxin
- IL-6
- Inflammation
- OD, Olfactory dysfunction
- Ob, Olfactory bulb
- Olfactory dysfunction
- Ot, Olfactory tract
- UHPLC-MS/MS, Ultra-performance liquid chromatography and tandem mass spectrometry
Collapse
Affiliation(s)
- Susanna P. Garamszegi
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA
| | - Linda L. Duque
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - James S. Metcalf
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA
| | - Elijah W. Stommel
- Department of Neurology, Dartmouth-Hitchcock Medical Center Department of Neurology, One Medical Center Dr., Lebanon, NH 03756, USA
- Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA
| | - David A. Davis
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Corresponding author.
| |
Collapse
|
3
|
Abstract
Micro RNAs (miRNAs) are short, non-coding RNAs with significant potential as diagnostic and prognostic biomarkers. However, a lack of reproducibility across studies has hindered their introduction into clinical settings. Inconsistencies between studies include a lack of consensus on the miRNAs associated with a specific disease and the direction of regulation. These differences may reflect the heterogenous nature of pathologies with multiple phenotypes, such as amyotrophic lateral sclerosis (ALS). It is also possible that discrepancies are due to different sampling, processing, and analysis protocols across labs. Using miRNA extracted from L1CAM immunoaffinity purified extracellular vesicles (neural-enriched extracellular vesicles or NEE), we thrice replicated an 8-miRNA fingerprint diagnostic of ALS, which includes the miRNA species and direction of regulation. We aimed to determine if the extra purification steps required to generate NEE created a unique extracellular vesicle (EV) fraction that might contribute to the robustness and replicability of our assay. We compared three fractions from control human plasma: 1) total heterogenous EVs (T), 2) L1CAM/neural enriched EVs (NEE), and 3) the remaining total-minus-NEE fraction (T-N). Each fraction was characterized for size, total protein content, and protein markers, then total RNA was extracted, and qPCR was run on 20 miRNAs. We report that the miRNA expression within NEE was different enough compared to T and T-N to justify the extra steps required to generate this fraction. We conclude that L1CAM immunocapture generates a unique fraction of EVs that consistently and robustly replicates a miRNA fingerprint which differentiates ALS patients from controls.
Collapse
|
4
|
Zhang F, Icyuz M, Tollefsbol T, Cox PA, Banack SA, Sun LY. L-Serine Influences Epigenetic Modifications to Improve Cognition and Behaviors in Growth Hormone-Releasing Hormone Knockout Mice. Biomedicines 2022; 11:biomedicines11010104. [PMID: 36672612 PMCID: PMC9856181 DOI: 10.3390/biomedicines11010104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 01/03/2023] Open
Abstract
Neurodegenerative diseases feature changes in cognition, and anxiety-like and autism-like behaviors, which are associated with epigenetic alterations such as DNA methylation and histone modifications. The amino acid L-serine has been shown to have beneficial effects on neurological symptoms. Here, we found that growth hormone-releasing hormone knockout (GHRH-KO) mice, a GH-deficiency mouse model characterized by extended lifespan and enhanced insulin sensitivity, showed a lower anxiety symptom and impairment of short-term object recognition memory and autism-like behaviors. Interestingly, L-serine administration exerted anxiolytic effects in mice and ameliorated the behavioral deficits in GHRH-KO. L-serine treatment upregulated histone epigenetic markers of H3K4me, H3K9ac, H3K14ac and H3K18ac in the hippocampus and H3K4me in the cerebral cortex in both GHRH-KO mice and wild type controls. L-serine-modulated epigenetic marker changes, in turn, were found to regulate mRNA expression of BDNF, grm3, foxp1, shank3, auts2 and marcksl1, which are involved in anxiety-, cognitive- and autism-like behaviors. Our study provides a novel insight into the beneficial effects of L-serine intervention on neuropsychological impairments.
Collapse
Affiliation(s)
- Fang Zhang
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35254, USA
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Mert Icyuz
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35254, USA
| | - Trygve Tollefsbol
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35254, USA
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA
| | - Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA
| | - Liou Y. Sun
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35254, USA
- Correspondence: ; Tel.: +(001)-205-934-48243
| |
Collapse
|
5
|
Banack SA, Dunlop RA, Stommel EW, Mehta P, Cox PA. miRNA extracted from extracellular vesicles is a robust biomarker of amyotrophic lateral sclerosis. J Neurol Sci 2022; 442:120396. [PMID: 36081303 DOI: 10.1016/j.jns.2022.120396] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 10/31/2022]
Abstract
BACKGROUND AND OBJECTIVES We examined miRNA biomarkers for ALS extracted from extracellular vesicles in blood samples using a large and diverse patient and control population. Different blood collection and storage protocols by different investigators could impact repeatability of miRNA analysis. We tested the hypotheses that miRNA extracted from extracellular vesicles using immunoaffinity purification techniques are robust and repeatable across investigators, laboratories and in a broad ALS population. METHODS De-identified patient blood plasma samples obtained from the U.S. National ALS Biorepository were compared with plasma from non-ALS controls. Extracellular vesicles were extracted and isolated using L1CAM immunoaffinity purification. Total RNA was extracted, and miRNA quantified using qPCR following careful quality control measures. Gene fold expressions of eight miRNAs were compared using a Mann-Whitney two-tailed test. RESULTS One hundred blinded, blood plasma samples were analyzed. Thirty-five men and 15 women with ALS were compared with controls consisting of 30 men and 20 women. None of the ALS patient cohort reported family members with ALS suggesting sporadic ALS. Five of the eight biomarkers previously published were found to significantly discriminate ALS patient samples from control samples. DISCUSSION The methods used in this study provide a repeatable measure of miRNA biomarkers that statistically differentiate ALS patient samples from control samples. The broad inclusion criteria for both the ALS patient cohort and controls along with the collection of blood samples by different investigators suggest that these methods are robust and represent good candidates for further research and development aimed at clinical application.
Collapse
Affiliation(s)
| | | | - Elijah W Stommel
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Paul Mehta
- Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry, National ALS Registry (CDC/ATSDR), Atlanta, GA, USA
| | | |
Collapse
|
6
|
Abstract
We sought to identify a usable biomarker from blood samples to characterize early-stage Alzheimer’s disease (AD) patients, in order to facilitate rapid diagnosis, early therapeutic intervention, and monitoring of clinical trials. We compared metabolites from blood plasma in early-stage Alzheimer’s disease patients with blood plasma from healthy controls using two different analytical platforms: Amino Acid Analyzer and Tandem Mass-Spectrometer. Early-stage Alzheimer’s patient blood samples were obtained during an FDA-approved Phase IIa clinical trial (Clinicaltrial.gov NCT03062449). Participants included 25 early-stage Alzheimer’s patients and 25 healthy controls in the United States. We measured concentrations of 2-aminoethyl dihydrogen phosphate and taurine in blood plasma samples. We found that plasma concentrations of a phospholipid metabolite, 2-aminoethyl dihydrogen phosphate, normalized by taurine concentrations, distinguish blood samples of patients with early-stage AD. This possible new Alzheimer’s biomarker may supplement clinical diagnosis for early detection of the disease.
Collapse
Affiliation(s)
| | - Aleksandra C. Stark
- Dartmouth-Hitchock Medical Center, Lebanon, New Hampshire, United States of America
| | - Paul Alan Cox
- Brain Chemistry Labs, Jackson, Wyoming, United States of America
- * E-mail:
| |
Collapse
|
7
|
Abstract
Glioblastoma multiforme (GBM) is the most aggressive cancer originating in the brain, with a median survival of 12 months. Most patients do not respond to or develop resistance to the only effective chemotherapeutic drug, temozolomide (TMZ), used to treat gliomas. Novel treatment methods are critically needed. Cyclotides are plant peptides that may be promising adjuvants to TMZ chemotherapy. They exhibit antitumor activity and chemosensitize cells to doxorubicin in breast cancer studies. During this research, we optimized cyclotide isolation techniques, and several cyclotides (CyO2, CyO13, kalata B1, and varv peptide A) exhibited dose-dependent cytotoxicity in MTT assays with IC50 values of 2.15-7.92 μM against human brain astrocytoma cells (U-87 MG) and human bone marrow derived neuroblastoma cells (SH-SY5Y). CyO2 and varv peptide A increased TMZ-induced cell death in U-87 MG cultures alone and when coexposed with CyO2 or varv peptide A plus TMZ. Phase contrast microscopy of glioblastoma cells exposed to cyclotides alone and coexposed to TMZ indicated shrunken, granular cells with blebbing, and the most pronounced effects were observed with coexposure treatments of cyclotides and TMZ. Cumulative results provide the proof-of-concept that cyclotides may enhance TMZ chemotherapy, and in vivo pharmacokinetic investigations of cyclotides are warranted with respect to GBM.
Collapse
Affiliation(s)
- Samantha L Gerlach
- Department of Biology, Dillard University, New Orleans, Louisiana 70122, United States
| | - Rachael A Dunlop
- Institute for Ethnomedicine, Brain Chemistry Laboratories, Box 3464, Jackson, Wyoming 83001, United States
| | - James S Metcalf
- Institute for Ethnomedicine, Brain Chemistry Laboratories, Box 3464, Jackson, Wyoming 83001, United States
| | - Sandra A Banack
- Institute for Ethnomedicine, Brain Chemistry Laboratories, Box 3464, Jackson, Wyoming 83001, United States
| | - Paul Alan Cox
- Institute for Ethnomedicine, Brain Chemistry Laboratories, Box 3464, Jackson, Wyoming 83001, United States
| |
Collapse
|
8
|
Davis DA, Garamszegi SP, Banack SA, Dooley PD, Coyne TM, McLean DW, Rotstein DS, Mash DC, Cox PA. BMAA, Methylmercury, and Mechanisms of Neurodegeneration in Dolphins: A Natural Model of Toxin Exposure. Toxins (Basel) 2021; 13:toxins13100697. [PMID: 34678990 PMCID: PMC8540894 DOI: 10.3390/toxins13100697] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/19/2021] [Accepted: 09/22/2021] [Indexed: 01/15/2023] Open
Abstract
Dolphins are well-regarded sentinels for toxin exposure and can bioaccumulate a cyanotoxin called β-N-methylamino-l-alanine (BMAA) that has been linked to human neurodegenerative disease. The same dolphins also possessed hallmarks of Alzheimer’s disease (AD), suggesting a possible association between toxin exposure and neuropathology. However, the mechanisms of neurodegeneration in dolphins and the impact cyanotoxins have on these processes are unknown. Here, we evaluate BMAA exposure by investigating transcription signatures using PCR for dolphin genes homologous to those implicated in AD and related dementias: APP, PSEN1, PSEN2, MAPT, GRN, TARDBP, and C9orf72. Immunohistochemistry and Sevier Münger silver staining were used to validate neuropathology. Methylmercury (MeHg), a synergistic neurotoxicant with BMAA, was also measured using PT-GC-AFS. We report that dolphins have up to a three-fold increase in gene transcription related to Aβ+ plaques, neurofibrillary tangles, neuritic plaques, and TDP-43+ intracytoplasmic inclusions. The upregulation of gene transcription in our dolphin cohort paralleled increasing BMAA concentration. In addition, dolphins with BMAA exposures equivalent to those reported in AD patients displayed up to a 14-fold increase in AD-type neuropathology. MeHg was detected (0.16–0.41 μg/g) and toxicity associated with exposure was also observed in the brain. These results demonstrate that dolphins develop neuropathology associated with AD and exposure to BMAA and MeHg may augment these processes.
Collapse
Affiliation(s)
- David A. Davis
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
- Correspondence:
| | - Susanna P. Garamszegi
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
| | - Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
| | - Patrick D. Dooley
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
| | - Thomas M. Coyne
- Office of the District 21 Medical Examiner, Fort Myers, FL 33907, USA;
| | - Dylan W. McLean
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
| | | | - Deborah C. Mash
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- Dr. Kiran C. Patel College of Allopathic Medicine, Nova Southeastern University, Davie, FL 33328, USA
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
| |
Collapse
|
9
|
Dunlop RA, Banack SA, Cox PA. A comparison of the efficiency of RNA extraction from extracellular vesicles using the Qiagen RNeasy MinElute versus Enzymax LLC RNA Tini Spin columns and qPCR of miRNA. Biol Methods Protoc 2021; 6:bpab015. [PMID: 34423131 PMCID: PMC8344526 DOI: 10.1093/biomethods/bpab015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 12/31/2022] Open
Abstract
One consequence of the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is an interruption to the supply of laboratory consumables, particularly those used for RNA extraction. This category includes column-based RNA extraction kits designed to retain short RNA species (defined as having fewer than 200 nucleotides), from small sample volumes, e.g. exosomes or extracellular vesicles (EVs). Qiagen manufactures several kits for the extraction and enrichment of short RNA species, such as microRNA (miRNA), which contain silica-membrane columns called “RNeasy MinElute Spin Columns.” These kits, which also contain buffers and collection tubes, range in price from USD380 to greater than USD1000 and have been subject to fulfillment delays. Scientists seeking to reduce single-use plastics and costs may wish to order the columns separately; however, Qiagen does not sell the RNeasy MinElute Spin Columns (in reasonable quantities) as an individual item. Thus, we sought an alternative product and found RNA Tini Spin columns from Enzymax LLC. We conducted a systematic comparison of the efficiency of RNA extraction for miRNA quantitative real-time PCR (qPCR) using the Qiagen RNeasy MinElute Spin Columns and Enzymax LLC RNA Tini Spin columns and the Qiagen total RNA extraction protocol that enriches for short RNA species. We compared the efficiency of extraction of five spike-in control miRNAs, six sample signal miRNAs, and nine low- to medium-abundance miRNAs by qPCR. The RNA was extracted from EV preparations purified from human plasma using CD81 immunoprecipitation. We report no statistically significant differences in extraction efficiencies between the two columns for any of the miRNAs examined. Therefore, we conclude that the Enzymax RNA Tini Spin columns are adequate substitutes for the Qiagen RNeasy MinElute Spin Columns for short RNA species enrichment and downstream qPCR from EVs in the miRNAs we examined.
Collapse
Affiliation(s)
| | - Sandra Anne Banack
- Brain Chemistry Labs, Suite 3, 1130 S Highway 89, Jackson, WY 83001, USA
| | - Paul Alan Cox
- Brain Chemistry Labs, Suite 3, 1130 S Highway 89, Jackson, WY 83001, USA
| |
Collapse
|
10
|
Davis DA, Cox PA, Banack SA, Lecusay PD, Garamszegi SP, Hagan MJ, Powell JT, Metcalf JS, Palmour RM, Beierschmitt A, Bradley WG, Mash DC. l-Serine Reduces Spinal Cord Pathology in a Vervet Model of Preclinical ALS/MND. J Neuropathol Exp Neurol 2020; 79:393-406. [PMID: 32077471 PMCID: PMC7092359 DOI: 10.1093/jnen/nlaa002] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/14/2020] [Indexed: 12/11/2022] Open
Abstract
The early neuropathological features of amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) are protein aggregates in motor neurons and microglial activation. Similar pathology characterizes Guamanian ALS/Parkinsonism dementia complex, which may be triggered by the cyanotoxin β-N-methylamino-l-alanine (BMAA). We report here the occurrence of ALS/MND-type pathological changes in vervets (Chlorocebus sabaeus; n = 8) fed oral doses of a dry powder of BMAA HCl salt (210 mg/kg/day) for 140 days. Spinal cords and brains from toxin-exposed vervets were compared to controls fed rice flour (210 mg/kg/day) and to vervets coadministered equal amounts of BMAA and l-serine (210 mg/kg/day). Immunohistochemistry and quantitative image analysis were used to examine markers of ALS/MND and glial activation. UHPLC-MS/MS was used to confirm BMAA exposures in dosed vervets. Motor neuron degeneration was demonstrated in BMAA-dosed vervets by TDP-43+ proteinopathy in anterior horn cells, by reactive astrogliosis, by activated microglia, and by damage to myelinated axons in the lateral corticospinal tracts. Vervets dosed with BMAA + l-serine displayed reduced neuropathological changes. This study demonstrates that chronic dietary exposure to BMAA causes ALS/MND-type pathological changes in the vervet and coadministration of l-serine reduces the amount of reactive gliosis and the number of protein inclusions in motor neurons.
Collapse
Affiliation(s)
- David A Davis
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Paul Alan Cox
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida.,Brain Chemistry Labs, Jackson Hole, Wyoming
| | - Sandra Anne Banack
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida.,Brain Chemistry Labs, Jackson Hole, Wyoming
| | | | | | - Matthew J Hagan
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida
| | | | | | - Roberta M Palmour
- Behavioural Science Foundation, St. Kitts and Nevis, West Indies.,Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Amy Beierschmitt
- Behavioural Science Foundation, St. Kitts and Nevis, West Indies.,Department of Clinical Sciences, Ross University School of Veterinary Medicine, St. Kitts and Nevis, West Indies
| | - Walter G Bradley
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Deborah C Mash
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, Florida.,Dr. Kiran C. Patel College of Allopathic Medicine, Nova Southeastern University, Davie, Florida
| |
Collapse
|
11
|
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
|
12
|
Metcalf JS, Banack SA, Wessel RA, Lester M, Pim JG, Cassani JR, Cox PA. Toxin Analysis of Freshwater Cyanobacterial and Marine Harmful Algal Blooms on the West Coast of Florida and Implications for Estuarine Environments. Neurotox Res 2020; 39:27-35. [PMID: 32683648 PMCID: PMC7904716 DOI: 10.1007/s12640-020-00248-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 06/18/2020] [Accepted: 06/22/2020] [Indexed: 02/07/2023]
Abstract
Recent marine and freshwater algal and cyanobacterial blooms in Florida have increased public concern and awareness of the risks posed by exposure to these organisms. In 2018, Lake Okeechobee and the Caloosahatchee river, on the west coast of Florida, experienced an extended bloom of Microcystis spp. and a bloom of Karenia brevis in the coastal waters of the Gulf of Mexico that coincided in the Fort Myers area. Samples from the Caloosahatchee at Fort Myers into Pine Island Sound and up to Boca Grande were collected by boat. High concentrations of microcystin-LR were detected in the cyanobacterial bloom along with brevetoxins in the marine samples. Furthermore, β-N-methylamino-L-alanine (BMAA) and isomers N-(2-aminoethyl)glycine (AEG) and 2,4-diaminobuytric acid (DAB) were detected in marine diatoms and dinoflagellates, and cyanobacteria of freshwater origin. High freshwater flows pushed the cyanobacterial bloom to barrier island beaches and Microcystis and microcystins could be detected into the marine environment at a salinity of 41 mS/cm. For comparison, in 2019 collections of Dapis (a new generic segregate from Lyngbya) mats from Sarasota showed high concentrations of BMAA, suggesting the possibility of long-term exposure of residents to BMAA. The findings highlight the potential for multiple, potentially toxic blooms to co-exist and the possible implications for human and animal health.
Collapse
Affiliation(s)
- J S Metcalf
- Brain Chemistry Labs, Jackson, WY, 83001, USA.
| | - S A Banack
- Brain Chemistry Labs, Jackson, WY, 83001, USA
| | - R A Wessel
- Sanibel-Captiva Conservation Foundation, Sanibel, FL, 33957, USA
| | - M Lester
- Path of Wellness Holistic Health, Lexington, GA, 30648, USA
| | - J G Pim
- Calusa Waterkeeper, Inc., PO Box 1165, Fort Myers, FL, 33902, USA
| | - J R Cassani
- Calusa Waterkeeper, Inc., PO Box 1165, Fort Myers, FL, 33902, USA
| | - P A Cox
- Brain Chemistry Labs, Jackson, WY, 83001, USA
| |
Collapse
|
13
|
Metcalf JS, Dunlop RA, Banack SA, Souza NR, Cox PA. Cyanotoxin Analysis and Amino Acid Profiles of Cyanobacterial Food Items from Chad. Neurotox Res 2020; 39:72-80. [PMID: 32654083 PMCID: PMC7904724 DOI: 10.1007/s12640-020-00240-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 05/28/2020] [Accepted: 06/10/2020] [Indexed: 11/12/2022]
Abstract
In some parts of the world, cyanobacteria are used as a food in the human diet, due to their ready availability. Lake Chad, has long been a traditional site for the collection of Arthrospira fusiformis which is dried and processed at the lake into thin wafers called Dihé for later consumption or is transported to market for sale. However, Dihé purchased from markets in Chad has not been analyzed for known cyanobacterial toxins or assessed for total amino acid content. Since BMAA in traditional foodstuffs of the indigenous Chamorro people of Guam causes neurodegenerative illness, it is important that Dihé from Chad be analyzed for this neurotoxin. BMAA and its isomer AEG were not detected in our analyses, but a further isomer DAB was detected as both a free and bound amino acid, with an increase in the free concentration after acid hydrolysis of this fraction. Microcystins were present in 6 samples at up to 20 μg/g according to UPLC-PDA, although their presence could not be confirmed using PCR for known microcystin synthetic genes. Amino acid analysis of the cyanobacterial material from Chad showed the presence of large amounts of canonical amino acids, suggesting that this may supplement indigenous people on low protein diets, although regular monitoring of the foodstuffs for the presence of cyanotoxins should be performed.
Collapse
Affiliation(s)
- J S Metcalf
- Brain Chemistry Labs, Box 3464, Jackson, WY, 83001, USA.
| | - R A Dunlop
- Brain Chemistry Labs, Box 3464, Jackson, WY, 83001, USA
| | - S A Banack
- Brain Chemistry Labs, Box 3464, Jackson, WY, 83001, USA
| | - N R Souza
- Brain Chemistry Labs, Box 3464, Jackson, WY, 83001, USA
| | - P A Cox
- Brain Chemistry Labs, Box 3464, Jackson, WY, 83001, USA
| |
Collapse
|
14
|
Banack SA, Dunlop RA, Cox PA. An miRNA fingerprint using neural-enriched extracellular vesicles from blood plasma: towards a biomarker for amyotrophic lateral sclerosis/motor neuron disease. Open Biol 2020; 10:200116. [PMID: 32574550 PMCID: PMC7333885 DOI: 10.1098/rsob.200116] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Biomarkers for amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) are currently not clinically available for disease diagnosis or analysis of disease progression. If identified, biomarkers could improve patient outcomes by enabling early intervention and assist in the determination of treatment efficacy. We hypothesized that neural-enriched extracellular vesicles could provide microRNA (miRNA) fingerprints with unequivocal signatures of neurodegeneration. Using blood plasma from ALS/MND patients and controls, we extracted neural-enriched extracellular vesicle fractions and conducted next-generation sequencing and qPCR of miRNA components of the transcriptome. We here report eight miRNA sequences which significantly distinguish ALS/MND patients from controls in a replicated experiment using a second cohort of patients and controls. miRNA sequences from patient blood samples using neural-enriched extracellular vesicles may yield unique insights into mechanisms of neurodegeneration and assist in early diagnosis of ALS/MND.
Collapse
Affiliation(s)
- Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, PO Box 3464, Jackson, WY 83001, USA
| | - Rachael Anne Dunlop
- Brain Chemistry Labs, Institute for Ethnomedicine, PO Box 3464, Jackson, WY 83001, USA
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, PO Box 3464, Jackson, WY 83001, USA
| |
Collapse
|
15
|
Chatziefthimiou AD, Banack SA, Cox PA. Biocrust-Produced Cyanotoxins Are Found Vertically in the Desert Soil Profile. Neurotox Res 2020; 39:42-48. [PMID: 32557323 DOI: 10.1007/s12640-020-00224-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/01/2020] [Accepted: 05/06/2020] [Indexed: 11/24/2022]
Abstract
The fate and persistence of the neurotoxin β-N-methylamino-L-alanine (BMAA) and its isomers N-(2aminoethyl)glycine (AEG) and 2,4-diaminobuytric acid (DAB) in soil profiles is poorly understood. In desert environments, these cyanotoxins are commonly found in both terrestrial and adjacent marine ecosystems; they accumulate in biocrusts and groundwater catchments, and have been previously shown to persist in soil as deep as 25 cm. To determine the depth that BMAA and its isomers can be found, samples were incrementally collected every 5 cm from bedrock to surface in triplicate soil cores in a biocrust field in the terrestrial desert of Qatar. Biocrust surface samples were also collected from each core priorly. Toxins were extracted from soil sub-samples, derivatized, and analyzed with UPLC-MS/MS. All toxins were detected in all soil cores at all depths. AEG and DAB were within a quantifiable concentration threshold; however, the low concentration of BMAA was considered below the threshold for quantification. This may have environmental health implications if these toxins are able to infiltrate and contaminate the bedrock aquifer, as well as the sand and gravel aquifers. Human and animal health may also be impacted through exposure to contaminated groundwater wells or through inhalation of aerosolized particles of soil, resuspended during construction or recreational activities.
Collapse
Affiliation(s)
| | - Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY, 83001, USA.
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY, 83001, USA
| |
Collapse
|
16
|
Davis DA, Mondo K, Stern E, Annor AK, Murch SJ, Coyne TM, Brand LE, Niemeyer ME, Sharp S, Bradley WG, Cox PA, Mash DC. Cyanobacterial neurotoxin BMAA and brain pathology in stranded dolphins. PLoS One 2019; 14:e0213346. [PMID: 30893348 PMCID: PMC6426197 DOI: 10.1371/journal.pone.0213346] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 02/20/2019] [Indexed: 12/29/2022] Open
Abstract
Dolphin stranding events occur frequently in Florida and Massachusetts. Dolphins are an excellent sentinel species for toxin exposures in the marine environment. In this report we examine whether cyanobacterial neurotoxin, β-methylamino-L-alanine (BMAA), is present in stranded dolphins. BMAA has been shown to bioaccumulate in the marine food web, including in the muscles and fins of sharks. Dietary exposure to BMAA is associated with the occurrence of neurofibrillary tangles and β-amyloid plaques in nonhuman primates. The findings of protein-bound BMAA in brain tissues from patients with Alzheimer’s disease has advanced the hypothesis that BMAA may be linked to dementia. Since dolphins are apex predators and consume prey containing high amounts of BMAA, we examined necropsy specimens to determine if dietary and environmental exposures may result in the accumulation of BMAA in the brains of dolphins. To test this hypothesis, we measured BMAA in a series of brains collected from dolphins stranded in Florida and Massachusetts using two orthogonal analytical methods: 1) high performance liquid chromatography, and 2) ultra-performance liquid chromatography with tandem mass spectrometry. We detected high levels of BMAA (20–748 μg/g) in the brains of 13 of 14 dolphins. To correlate neuropathological changes with toxin exposure, gross and microscopic examinations were performed on cortical brain regions responsible for acoustico-motor navigation. We observed increased numbers of β-amyloid+ plaques and dystrophic neurites in the auditory cortex compared to the visual cortex and brainstem. The presence of BMAA and neuropathological changes in the stranded dolphin brain may help to further our understanding of cyanotoxin exposure and its potential impact on human health.
Collapse
Affiliation(s)
- David A. Davis
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- * E-mail: (DM); (DD)
| | - Kiyo Mondo
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Erica Stern
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Ama K. Annor
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Susan J. Murch
- Department of Chemistry, University of British Columbia, Kelowna, British Columbia, Canada
| | - Thomas M. Coyne
- Office of the District 21 Medical Examiner, Fort Myers, Florida, United States of America
| | - Larry E. Brand
- Divisions of Marine Biology and Fisheries and NSF/NIEHS Oceans and Human Health Center, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, United States of America
| | - Misty E. Niemeyer
- Marine Mammal Rescue and Research, International Fund for Animal Welfare (IFAW), Yarmouth Port, Massachusetts, United States of America
| | - Sarah Sharp
- Marine Mammal Rescue and Research, International Fund for Animal Welfare (IFAW), Yarmouth Port, Massachusetts, United States of America
| | - Walter G. Bradley
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson Hole, Wyoming, United States of America
| | - Deborah C. Mash
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- * E-mail: (DM); (DD)
| |
Collapse
|
17
|
Dunlop RA, Powell J, Guillemin GJ, Cox PA. Mechanisms of L-Serine Neuroprotection in vitro Include ER Proteostasis Regulation. Neurotox Res 2017; 33:123-132. [PMID: 29098664 DOI: 10.1007/s12640-017-9829-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 09/27/2017] [Accepted: 10/06/2017] [Indexed: 01/14/2023]
Abstract
β-N-methylamino-L-alanine (L-BMAA) is a neurotoxic non-protein amino acid produced by cyanobacteria. Recently, chronic dietary exposure to L-BMAA was shown to trigger neuropathology in nonhuman primates consistent with Guamanian ALS/PDC, a paralytic disease that afflicts Chamorro villagers who consume traditional food items contaminated with L-BMAA. However, the addition of the naturally occurring amino acid L-serine to the diet of the nonhuman primates resulted in a significant reduction in ALS/PDC neuropathology. L-serine is a dietary amino acid that plays a crucial role in central nervous system development, neuronal signaling, and synaptic plasticity and has been shown to impart neuroprotection from L-BMAA-induced neurotoxicity both in vitro and in vivo. We have previously shown that L-serine prevents the formation of autofluorescent aggregates and death by apoptosis in human cell lines and primary cells. These effects are likely imparted by L-serine blocking incorporation of L-BMAA into proteins hence preventing proteotoxic stress. However, there are likely other mechanisms for L-serine-mediated neuroprotection. Here, we explore the molecular mechanisms of L-serine neuroprotection using a human unfolded protein response real-time PCR array with genes from the ER stress and UPR pathways, and western blotting. We report that L-serine caused the differential expression of many of the same genes as L-BMAA, even though concentrations of L-serine in the culture medium were ten times lower than that of L-BMAA. We propose that L-serine may be functioning as a small proteostasis regulator, in effect altering the cells to quickly respond to a possible oxidative insult, thus favoring a return to homeostasis.
Collapse
Affiliation(s)
- R A Dunlop
- Brain Chemistry Labs, The Institute for Ethnomedicine, Jackson, WY, USA.,Neuroinflammation Group, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - J Powell
- Brain Chemistry Labs, The Institute for Ethnomedicine, Jackson, WY, USA
| | - G J Guillemin
- Neuroinflammation Group, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - P A Cox
- Brain Chemistry Labs, The Institute for Ethnomedicine, Jackson, WY, USA.
| |
Collapse
|
18
|
Metcalf JS, Dunlop RA, Powell JT, Banack SA, Cox PA. L-Serine: a Naturally-Occurring Amino Acid with Therapeutic Potential. Neurotox Res 2017; 33:213-221. [PMID: 28929385 DOI: 10.1007/s12640-017-9814-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 08/25/2017] [Accepted: 09/05/2017] [Indexed: 01/08/2023]
Abstract
In human neuroblastoma cell cultures, non-human primates and human beings, L-serine is neuroprotective, acting through a variety of biochemical and molecular mechanisms. Although L-serine is generally classified as a non-essential amino acid, it is probably more appropriate to term it as a "conditional non-essential amino acid" since, under certain circumstances, vertebrates cannot synthesize it in sufficient quantities to meet necessary cellular demands. L-serine is biosynthesized in the mammalian central nervous system from 3-phosphoglycerate and serves as a precursor for the synthesis of the amino acids glycine and cysteine. Physiologically, it has a variety of roles, perhaps most importantly as a phosphorylation site in proteins. Mutations in the metabolic enzymes that synthesize L-serine have been implicated in various human diseases. Dosing of animals with L-serine and human clinical trials investigating the therapeutic effects of L-serine support the FDA's determination that L-serine is generally regarded as safe (GRAS); it also appears to be neuroprotective. We here consider the role of L-serine in neurological disorders and its potential as a therapeutic agent.
Collapse
Affiliation(s)
- J S Metcalf
- Brain Chemistry Labs, The Institute for Ethnomedicine, Jackson, 83001, WY, USA
| | - R A Dunlop
- Brain Chemistry Labs, The Institute for Ethnomedicine, Jackson, 83001, WY, USA
| | - J T Powell
- Brain Chemistry Labs, The Institute for Ethnomedicine, Jackson, 83001, WY, USA
| | - S A Banack
- Brain Chemistry Labs, The Institute for Ethnomedicine, Jackson, 83001, WY, USA
| | - P A Cox
- Brain Chemistry Labs, The Institute for Ethnomedicine, Jackson, 83001, WY, USA.
| |
Collapse
|
19
|
Kokubo Y, Banack SA, Morimoto S, Murayama S, Togashi T, Metcalf JS, Cox PA, Kuzuhara S. β-N-methylamino-l-alanine analysis in the brains of patients with Kii ALS/PDC. Neurology 2017; 89:1091-1092. [PMID: 28794246 DOI: 10.1212/wnl.0000000000004310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 05/30/2017] [Indexed: 11/15/2022] Open
Affiliation(s)
- Yasumasa Kokubo
- From the Kii ALS/PDC Research Center (Y.K.), Graduate School of Regional Innovation Studies and Department of Oncologic Pathology (S.M.), Mie University, Tsu, Japan; Brain Chemistry Labs (S.A.B., J.S.M., P.A.C.), Institute for Ethnomedicine, Jackson, WY; Tokyo Metropolitan Geriatric Hospital (S.M.); Marine Biosystems Research Center (T.T.), Chiba University; and Suzuka University of Medical Science (S.K.), Japan.
| | - Sandra Anne Banack
- From the Kii ALS/PDC Research Center (Y.K.), Graduate School of Regional Innovation Studies and Department of Oncologic Pathology (S.M.), Mie University, Tsu, Japan; Brain Chemistry Labs (S.A.B., J.S.M., P.A.C.), Institute for Ethnomedicine, Jackson, WY; Tokyo Metropolitan Geriatric Hospital (S.M.); Marine Biosystems Research Center (T.T.), Chiba University; and Suzuka University of Medical Science (S.K.), Japan
| | - Satoru Morimoto
- From the Kii ALS/PDC Research Center (Y.K.), Graduate School of Regional Innovation Studies and Department of Oncologic Pathology (S.M.), Mie University, Tsu, Japan; Brain Chemistry Labs (S.A.B., J.S.M., P.A.C.), Institute for Ethnomedicine, Jackson, WY; Tokyo Metropolitan Geriatric Hospital (S.M.); Marine Biosystems Research Center (T.T.), Chiba University; and Suzuka University of Medical Science (S.K.), Japan
| | - Shigeo Murayama
- From the Kii ALS/PDC Research Center (Y.K.), Graduate School of Regional Innovation Studies and Department of Oncologic Pathology (S.M.), Mie University, Tsu, Japan; Brain Chemistry Labs (S.A.B., J.S.M., P.A.C.), Institute for Ethnomedicine, Jackson, WY; Tokyo Metropolitan Geriatric Hospital (S.M.); Marine Biosystems Research Center (T.T.), Chiba University; and Suzuka University of Medical Science (S.K.), Japan
| | - Tatsuya Togashi
- From the Kii ALS/PDC Research Center (Y.K.), Graduate School of Regional Innovation Studies and Department of Oncologic Pathology (S.M.), Mie University, Tsu, Japan; Brain Chemistry Labs (S.A.B., J.S.M., P.A.C.), Institute for Ethnomedicine, Jackson, WY; Tokyo Metropolitan Geriatric Hospital (S.M.); Marine Biosystems Research Center (T.T.), Chiba University; and Suzuka University of Medical Science (S.K.), Japan
| | - James S Metcalf
- From the Kii ALS/PDC Research Center (Y.K.), Graduate School of Regional Innovation Studies and Department of Oncologic Pathology (S.M.), Mie University, Tsu, Japan; Brain Chemistry Labs (S.A.B., J.S.M., P.A.C.), Institute for Ethnomedicine, Jackson, WY; Tokyo Metropolitan Geriatric Hospital (S.M.); Marine Biosystems Research Center (T.T.), Chiba University; and Suzuka University of Medical Science (S.K.), Japan
| | - Paul Alan Cox
- From the Kii ALS/PDC Research Center (Y.K.), Graduate School of Regional Innovation Studies and Department of Oncologic Pathology (S.M.), Mie University, Tsu, Japan; Brain Chemistry Labs (S.A.B., J.S.M., P.A.C.), Institute for Ethnomedicine, Jackson, WY; Tokyo Metropolitan Geriatric Hospital (S.M.); Marine Biosystems Research Center (T.T.), Chiba University; and Suzuka University of Medical Science (S.K.), Japan
| | - Shigeki Kuzuhara
- From the Kii ALS/PDC Research Center (Y.K.), Graduate School of Regional Innovation Studies and Department of Oncologic Pathology (S.M.), Mie University, Tsu, Japan; Brain Chemistry Labs (S.A.B., J.S.M., P.A.C.), Institute for Ethnomedicine, Jackson, WY; Tokyo Metropolitan Geriatric Hospital (S.M.); Marine Biosystems Research Center (T.T.), Chiba University; and Suzuka University of Medical Science (S.K.), Japan
| |
Collapse
|
20
|
Metcalf JS, Lobner D, Banack SA, Cox GA, Nunn PB, Wyatt PB, Cox PA. Analysis of BMAA enantiomers in cycads, cyanobacteria, and mammals: in vivo formation and toxicity of D-BMAA. Amino Acids 2017. [PMID: 28620737 DOI: 10.1007/s00726-017-2445-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Chronic dietary exposure to the cyanobacterial toxin β-N-methylamino-L-alanine (BMAA) triggers neuropathology in non-human primates, providing support for the theory that BMAA causes a fatal neurodegenerative illness among the indigenous Chamorro people of Guam. However, since there are two stereoisomers of BMAA, it is important to know if both can occur in nature, and if so, what role they might play in disease causation. As a first step, we analysed both BMAA enantiomers in cyanobacteria, cycads, and in mammals orally dosed with L-BMAA, to determine if enantiomeric changes could occur in vivo. BMAA in cyanobacteria and cycads was found only as the L-enantiomer. However, while the L-enantiomer in mammals was little changed after digestion, we detected a small pool of D-BMAA in the liver (12.5%) of mice and in the blood plasma of vervets (3.6%). Chiral analysis of cerebrospinal fluid of vervets and hindbrain of mice showed that the free BMAA in the central nervous system was the D-enantiomer. In vitro toxicity investigations with D-BMAA showed toxicity, mediated through AMPA rather than NMDA receptors. These findings raise important considerations concerning the neurotoxicity of BMAA and its relationship to neurodegenerative disease.
Collapse
Affiliation(s)
- J S Metcalf
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY, 83001, USA.
| | - Doug Lobner
- Department of Biomedical Sciences, College of Health Sciences, Marquette University, Milwaukee, WI, 53201, USA
| | - Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY, 83001, USA
| | | | - Peter B Nunn
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, PD1 2DT, UK
| | - Peter B Wyatt
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY, 83001, USA
| |
Collapse
|
21
|
Abstract
The cyanobacterial toxin β-N-methylamino-L-alanine (BMAA) now appears to be a cause of Guamanian amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC). Its production by cyanobacteria throughout the world combined with multiple mechanisms of BMAA neurotoxicity, particularly to vulnerable subpopulations of motor neurons, has significantly increased interest in investigating exposure to this non-protein amino acid as a possible risk factor for other forms of neurodegenerative illness. We here provide a brief overview of BMAA studies and provide an introduction to this collection of scientific manuscripts in this special issue on BMAA.
Collapse
Affiliation(s)
- Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, PO Box 3464, Jackson Hole, WY, 83001, USA.
| | - Richard M Kostrzewa
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, PO Box 70577, Johnson City, TN, 37614, USA
| | - Gilles J Guillemin
- Macquarie University, MND Research Centre, FMHS, 2 Technology Place, Sydney, NSW, 2109, Australia
| |
Collapse
|
22
|
Banack SA, Cox PA. Creating a Simian Model of Guam ALS/PDC Which Reflects Chamorro Lifetime BMAA Exposures. Neurotox Res 2017; 33:24-32. [PMID: 28478528 DOI: 10.1007/s12640-017-9745-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/03/2017] [Accepted: 04/21/2017] [Indexed: 12/26/2022]
Abstract
The theory that β-N-methylamino-L-alanine (BMAA), a cyanobacterial toxin, contaminates traditional food supplies of the Chamorro people of Guam is supported by the recent finding that chronic dietary exposure to L-BMAA in vervets (Chlorocebus sabaeus) triggers the formation of neurofibrillary tangles (NFT) and β-amyloid plaques in the brain. In the first experiment, we found that all four vervets receiving a 210 mg/kg dose for 140 days developed NFT and sparse amyloid deposits. In the second experiment, all eight vervets receiving a 210 mg/kg dose for 140 days developed NFT and amyloid deposits, as well as all eight vervets that received only 21 mg/kg. Based on dietary surveys of the Chamorro people, we estimated lifetime chronic BMAA exposure at a high and a low level: 1) adult male Chamorros eating two flying foxes per month plus one 30 g serving of cycad flour per week; and 2) adult male Chamorros eating one 30 g serving of cycad flour per day combined with the consumption of eight flying foxes per month. The resultant cumulative lifetime Chamorro exposures ranged from 1 to 41 g/kg and are comparable to the total lifetime vervet exposures in our experiments of 2 and 22 g/kg, respectively. Furthermore, measured protein-bound BMAA concentrations of vervets fed L-BMAA powder are comparable to measured protein-bound BMAA concentrations in postmortem brain tissues of Chamorros who died with ALS/PDC.
Collapse
Affiliation(s)
- Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY, 83001, USA.
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY, 83001, USA
| |
Collapse
|
23
|
Cox PA, Metcalf JS. Erratum to: Traditional Food Items in Ogimi, Okinawa: l-Serine Content and the Potential for Neuroprotection. Curr Nutr Rep 2017. [DOI: 10.1007/s13668-017-0192-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
24
|
Abstract
Purpose of Review Ogimi village is renowned for its aging population. We sought to determine if the l-serine content of their diet could account for their neurological health. Recent Findings The most frequently consumed food items, including tofu and seaweeds, are rich in the dietary amino acid l-serine. l-serine content of the Ogimi diet >8 grams/day for Ogimi women significantly exceeds the average American dietary intake of 2.5 grams/day for women >70 years old. Summary Our hypothesis that the high l-serine content of the Ogimi diet is related to the paucity of tangle diseases among villagers is buttressed by in vivo results with non-human primates where dietary l-serine slowed development of neurofibrillary tangles and β-amyloid plaques by up to 85% and a human clinical trial finding that l-serine at 15 grams/day twice daily slows functional decline in ALS patients. Analysis of the Ogimi diet suggests that l-serine should be evaluated for therapeutic potential as a neuroprotective agent.
Collapse
Affiliation(s)
- Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY 83001 USA
| | - James S Metcalf
- Brain Chemistry Labs, Institute for Ethnomedicine, Box 3464, Jackson, WY 83001 USA
| |
Collapse
|
25
|
Cox PA, Davis DA, Mash DC, Metcalf JS, Banack SA. Do vervets and macaques respond differently to BMAA? Neurotoxicology 2016; 57:310-311. [DOI: 10.1016/j.neuro.2016.04.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 04/26/2016] [Accepted: 04/26/2016] [Indexed: 02/06/2023]
|
26
|
Cox PA, Davis DA, Mash DC, Metcalf JS, Banack SA. Dietary exposure to an environmental toxin triggers neurofibrillary tangles and amyloid deposits in the brain. Proc Biol Sci 2016; 283:rspb.2015.2397. [PMID: 26791617 PMCID: PMC4795023 DOI: 10.1098/rspb.2015.2397] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Neurofibrillary tangles (NFT) and β-amyloid plaques are the neurological hallmarks of both Alzheimer's disease and an unusual paralytic illness suffered by Chamorro villagers on the Pacific island of Guam. Many Chamorros with the disease suffer dementia, and in some villages one-quarter of the adults perished from the disease. Like Alzheimer's, the causal factors of Guamanian amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC) are poorly understood. In replicated experiments, we found that chronic dietary exposure to a cyanobacterial toxin present in the traditional Chamorro diet, β-N-methylamino-l-alanine (BMAA), triggers the formation of both NFT and β-amyloid deposits similar in structure and density to those found in brain tissues of Chamorros who died with ALS/PDC. Vervets (Chlorocebus sabaeus) fed for 140 days with BMAA-dosed fruit developed NFT and sparse β-amyloid deposits in the brain. Co-administration of the dietary amino acid l-serine with l-BMAA significantly reduced the density of NFT. These findings indicate that while chronic exposure to the environmental toxin BMAA can trigger neurodegeneration in vulnerable individuals, increasing the amount of l-serine in the diet can reduce the risk.
Collapse
Affiliation(s)
| | - David A Davis
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Deborah C Mash
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | | | | |
Collapse
|
27
|
Banack SA, Caller T, Henegan P, Haney J, Murby A, Metcalf JS, Powell J, Cox PA, Stommel E. Detection of cyanotoxins, β-N-methylamino-L-alanine and microcystins, from a lake surrounded by cases of amyotrophic lateral sclerosis. Toxins (Basel) 2015; 7:322-36. [PMID: 25643180 PMCID: PMC4344626 DOI: 10.3390/toxins7020322] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 12/12/2014] [Accepted: 01/21/2015] [Indexed: 11/16/2022] Open
Abstract
A cluster of amyotrophic lateral sclerosis (ALS) has been previously described to border Lake Mascoma in Enfield, NH, with an incidence of ALS approximating 25 times expected. We hypothesize a possible association with cyanobacterial blooms that can produce β-N-methylamino-L-alanine (BMAA), a neurotoxic amino acid implicated as a possible cause of ALS/PDC in Guam. Muscle, liver, and brain tissue samples from a Lake Mascoma carp, as well as filtered aerosol samples, were analyzed for microcystins (MC), free and protein-bound BMAA, and the BMAA isomers 2,4-diaminobutyric acid (DAB) and N-(2-aminoethyl)glycine (AEG). In carp brain, BMAA and DAB concentrations were 0.043 μg/g ± 0.02 SD and 0.01 μg/g ± 0.002 SD respectively. In carp liver and muscle, the BMAA concentrations were 1.28 μg/g and 1.27 μg/g respectively, and DAB was not detected. BMAA was detected in the air filters, as were the isomers DAB and AEG. These results demonstrate that a putative cause for ALS, BMAA, exists in an environment that has a documented cluster of ALS. Although cause and effect have not been demonstrated, our observations and measurements strengthen the association.
Collapse
Affiliation(s)
| | - Tracie Caller
- Cheyenne Regional Medical Group, Cheyenne, WY 82001, USA.
| | - Patricia Henegan
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.
| | - James Haney
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA.
| | - Amanda Murby
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA.
| | - James S Metcalf
- Institute for Ethnomedicine, PO Box 3464, Jackson, WY 83001, USA.
| | - James Powell
- Institute for Ethnomedicine, PO Box 3464, Jackson, WY 83001, USA.
| | - Paul Alan Cox
- Institute for Ethnomedicine, PO Box 3464, Jackson, WY 83001, USA.
| | - Elijah Stommel
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.
| |
Collapse
|
28
|
Banack SA, Metcalf JS, Bradley WG, Cox PA. Detection of cyanobacterial neurotoxin β-N-methylamino-l-alanine within shellfish in the diet of an ALS patient in Florida. Toxicon 2014; 90:167-73. [PMID: 25123936 DOI: 10.1016/j.toxicon.2014.07.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 05/30/2014] [Accepted: 07/30/2014] [Indexed: 01/13/2023]
Abstract
Cyanobacteria produce the neurotoxic amino acid β-N-methylamino-l-alanine (BMAA), which in contaminated marine waters has been found to accumulate in shellfish. Exposure to BMAA has been associated with an increased risk of neurodegenerative disease. Analysis of blinded samples found BMAA to be present in neuroproteins of individuals who died from ALS and ALS/PDC, but generally not in the brains of patients who died of causes unrelated to neurodegeneration or Huntington's disease, an autosomal dominant neurodegenerative disease. We here report support for a link between a patient with ALS and chronic exposure to the cyanobacterial neurotoxin BMAA via shellfish consumption. The patient had frequently eaten lobsters collected in Florida Bay for approximately 30 years. LC-MS/MS analysis of two lobsters which this ALS patient had placed in his freezer revealed BMAA at concentrations of 27 and 4 μg/g, respectively, as well as the presence of 2,4-diaminobutyric acid (DAB), a BMAA isomer. Two additional lobsters recently collected from Florida Bay also contained the neurotoxins BMAA and DAB. These data suggest that invertebrates collected in water where cyanobacterial blooms are present, if consumed, may result in direct human exposure to these neurotoxic amino acids. The data support the assertion that prolonged exposure to BMAA may have played a role in the etiology of ALS in this patient.
Collapse
Affiliation(s)
| | - James S Metcalf
- Institute for Ethnomedicine, Box 3464, Jackson Hole, WY 83001, USA.
| | - Walter G Bradley
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA.
| | - Paul Alan Cox
- Institute for Ethnomedicine, Box 3464, Jackson Hole, WY 83001, USA.
| |
Collapse
|
29
|
Dunlop RA, Cox PA, Banack SA, Rodgers KJ. The non-protein amino acid BMAA is misincorporated into human proteins in place of L-serine causing protein misfolding and aggregation. PLoS One 2013; 8:e75376. [PMID: 24086518 PMCID: PMC3783393 DOI: 10.1371/journal.pone.0075376] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 07/17/2013] [Indexed: 12/25/2022] Open
Abstract
Mechanisms of protein misfolding are of increasing interest in the aetiology of neurodegenerative diseases characterized by protein aggregation and tangles including Amyotrophic Lateral Sclerosis (ALS), Alzheimer’s disease (AD), Parkinson’s disease (PD), Lewy Body Dementia (LBD), and Progressive Supranuclear Palsy (PSP). Some forms of neurodegenerative illness are associated with mutations in genes which control assembly of disease related proteins. For example, the mouse sticky mutation sti, which results in undetected mischarging of tRNAAla with serine resulting in the substitution of serine for alanine in proteins causes cerebellar Purkinje cell loss and ataxia in laboratory animals. Replacement of serine 422 with glutamic acid in tau increases the propensity of tau aggregation associated with neurodegeneration. However, the possibility that environmental factors can trigger abnormal folding in proteins remains relatively unexplored. We here report that a non-protein amino acid, β-N-methylamino-L-alanine (BMAA), can be misincorporated in place of l-serine into human proteins. We also report that this misincorporation can be inhibited by l-serine. Misincorporation of BMAA into human neuroproteins may shed light on putative associations between human exposure to BMAA produced by cyanobacteria and an increased incidence of ALS.
Collapse
Affiliation(s)
- Rachael Anne Dunlop
- Cell Biology Group, School of Medical and Molecular Biosciences, University of Technology Sydney, Ultimo, New South Wales, Australia
| | - Paul Alan Cox
- Institute for Ethnomedicine, Jackson Hole, Wyoming, United States of America
| | - Sandra Anne Banack
- Institute for Ethnomedicine, Jackson Hole, Wyoming, United States of America
| | - Kenneth John Rodgers
- Cell Biology Group, School of Medical and Molecular Biosciences, University of Technology Sydney, Ultimo, New South Wales, Australia
- * E-mail:
| |
Collapse
|
30
|
Bradley WG, Borenstein AR, Nelson LM, Codd GA, Rosen BH, Stommel EW, Cox PA. Is exposure to cyanobacteria an environmental risk factor for amyotrophic lateral sclerosis and other neurodegenerative diseases? Amyotroph Lateral Scler Frontotemporal Degener 2013; 14:325-33. [PMID: 23286757 DOI: 10.3109/21678421.2012.750364] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
There is a broad scientific consensus that amyotrophic lateral sclerosis (ALS) is caused by gene-environment interactions. Mutations in genes underlying familial ALS (fALS) have been discovered in only 5-10% of the total population of ALS patients. Relatively little attention has been paid to environmental and lifestyle factors that may trigger the cascade of motor neuron death leading to the syndrome of ALS, although exposure to chemicals including lead and pesticides, and to agricultural environments, smoking, certain sports, and trauma have all been identified with an increased risk of ALS. There is a need for research to quantify the relative roles of each of the identified risk factors for ALS. Recent evidence has strengthened the theory that chronic environmental exposure to the neurotoxic amino acid β-N-methylamino-L-alanine (BMAA) produced by cyanobacteria may be an environmental risk factor for ALS. Here we describe methods that may be used to assess exposure to cyanobacteria, and hence potentially to BMAA, namely an epidemiologic questionnaire and direct and indirect methods for estimating the cyanobacterial load in ecosystems. Rigorous epidemiologic studies could determine the risks associated with exposure to cyanobacteria, and if combined with genetic analysis of ALS cases and controls could reveal etiologically important gene-environment interactions in genetically vulnerable individuals.
Collapse
Affiliation(s)
- Walter G Bradley
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA.
| | | | | | | | | | | | | |
Collapse
|
31
|
Banack SA, Metcalf JS, Jiang L, Craighead D, Ilag LL, Cox PA. Cyanobacteria produce N-(2-aminoethyl)glycine, a backbone for peptide nucleic acids which may have been the first genetic molecules for life on Earth. PLoS One 2012; 7:e49043. [PMID: 23145061 PMCID: PMC3492184 DOI: 10.1371/journal.pone.0049043] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 10/05/2012] [Indexed: 11/18/2022] Open
Abstract
Prior to the evolution of DNA-based organisms on earth over 3.5 billion years ago it is hypothesized that RNA was the primary genetic molecule. Before RNA-based organisms arose, peptide nucleic acids may have been used to transmit genetic information by the earliest forms of life on earth. We discovered that cyanobacteria produce N-(2-aminoethyl)glycine (AEG), a backbone for peptide nucleic acids. We detected AEG in axenic strains of cyanobacteria with an average concentration of 1 µg/g. We also detected AEG in environmental samples of cyanobacteria as both a free or weakly bound molecule and a tightly bound form released by acid hydrolysis, at concentrations ranging from not detected to 34 µg/g. The production of AEG by diverse taxa of cyanobacteria suggests that AEG may be a primitive feature which arose early in the evolution of life on earth.
Collapse
Affiliation(s)
| | - James S. Metcalf
- Institute for Ethnomedicine, Jackson, Wyoming, United States of America
| | - Liying Jiang
- Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Derek Craighead
- Craighead Beringia South, Kelly, Wyoming, United States of America
| | - Leopold L. Ilag
- Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Paul Alan Cox
- Institute for Ethnomedicine, Jackson, Wyoming, United States of America
- * E-mail:
| |
Collapse
|
32
|
Togashi T, Bartelt JL, Yoshimura J, Tainaka KI, Cox PA. Evolutionary trajectories explain the diversified evolution of isogamy and anisogamy in marine green algae. Proc Natl Acad Sci U S A 2012; 109:13692-7. [PMID: 22869736 PMCID: PMC3427103 DOI: 10.1073/pnas.1203495109] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The evolution of anisogamy (the production of gametes of different size) is the first step in the establishment of sexual dimorphism, and it is a fundamental phenomenon underlying sexual selection. It is believed that anisogamy originated from isogamy (production of gametes of equal size), which is considered by most theorists to be the ancestral condition. Although nearly all plant and animal species are anisogamous, extant species of marine green algae exhibit a diversity of mating systems including both isogamy and anisogamy. Isogamy in marine green algae is of two forms: isogamy with extremely small gametes and isogamy with larger gametes. Based on disruptive selection for fertilization success and zygote survival (theory of Parker, Baker, and Smith), we explored how environmental changes can contribute to the evolution of such complex mating systems by analyzing the stochastic process in the invasion simulations of populations of differing gamete sizes. We find that both forms of isogamy can evolve from other isogamous ancestors through anisogamy. The resulting dimensionless analysis accounts for the evolutionary stability of all types of mating systems in marine green algae, even in the same environment. These results imply that evolutionary trajectories as well as the optimality of gametes/zygotes played an important role in the evolution of gamete size.
Collapse
Affiliation(s)
- Tatsuya Togashi
- Marine Biosystems Research Center, Chiba University, Kamogawa 299-5502, Japan.
| | | | | | | | | |
Collapse
|
33
|
Metcalf JS, Richer R, Cox PA, Codd GA. Cyanotoxins in desert environments may present a risk to human health. Sci Total Environ 2012; 421-422:118-23. [PMID: 22369867 DOI: 10.1016/j.scitotenv.2012.01.053] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 01/26/2012] [Accepted: 01/26/2012] [Indexed: 04/15/2023]
Abstract
There have been few studies concerning cyanotoxins in desert environments, compared with the multitude of studies of cyanotoxins in aquatic environments. However, cyanobacteria are important primary producers in desert environments, where after seasonal rains they can grow rapidly both stabilising and fertilising arid habitats. Samples of cyanobacteria from wadis - dry, ephemeral river beds - and sabkha - supertidal salt flats - in Qatar were analysed for the presence of microcystins, nodularin, anatoxin-a, cylindrospermopsin and anatoxin-a(S). Microcystins were detected by HPLC-PDA and ELISA at concentrations between 1.5 and 53.7ngg(-1) dry wt of crust. PCR products for the mycD gene for microcystin biosynthesis were detected after amplification of DNA from desert crust samples at two out of three sample sites. The presence of anatoxin-a(S) was also indicated by acetylcholine esterase inhibition assay. As a function of area of desert crust, microcystin concentrations were between 3 and 56μgm(-2). Based on the concentration of microcystins detected in crust, with reference to the published inhalation NOAEL and LOAEL values via nasal spray inhalation of purified microcystin-LR in aqueous solution, and the amount of dust potentially inhaled by a person from these dried crusts, the dose of microcystins could exceed a calculated TDI value of 1-2ngkg(-1)day(-1) for an average adult. The presence of microcystins, and potentially of anatoxin-a(S), in desert crusts has important implications for human health. Further studies are required to monitor desert dust storms for the presence of cyanotoxins. An understanding of the risks of inhaling particles containing cyanotoxins is also warranted.
Collapse
Affiliation(s)
- J S Metcalf
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 4HN, UK.
| | | | | | | |
Collapse
|
34
|
Togashi T, Sakakibara K, Nozawa M, Cox PA. Sexual fusion of protoplasts in a marine green alga, Bryopsis plumosa. Sex Plant Reprod 2012; 25:71-6. [PMID: 22228469 DOI: 10.1007/s00497-011-0180-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 12/25/2011] [Indexed: 11/30/2022]
Abstract
We isolated protoplasts from male and female gametophytes of a strictly dioecious strain of the coenocytic marine green alga Bryopsis plumosa. The protoplasts successfully developed into macrothalli. These in turn produced swimming cells, which appeared similar to biflagellated gametes even when the mixed protoplasts were comprised of protoplasm from male and female gametophytes. We found that swimming cell sizes depended on the male/female protoplasm ratio; macrothalli successfully produced swimming cells with male/female protoplasm ratios of 10:0; 9:1; 7:3; 5:5; 1:9; and 0:10. In male/female protoplasm ratios ranging from equal to strongly female biased (5:5; 3:7; 1:9), swimming cells exhibited normal behaviors of gametes and resultant zygotes, displaying positive and negative phototaxis, respectively. Negatively phototactic swimming cells were quadriflagellated and had two nuclei, apparently as a result of fusion, but never developed into microthalli. Thus, these swimming cells might lack functionality essential for normal gametes. Our findings suggested that natural monoecy observed in this genus did not originate from hybridization of protoplasm between the sexes.
Collapse
Affiliation(s)
- Tatsuya Togashi
- Marine Biosystems Research Center, Chiba University, Kamogawa 299-5502, Japan.
| | | | | | | |
Collapse
|
35
|
Banack SA, Metcalf JS, Spáčil Z, Downing TG, Downing S, Long A, Nunn PB, Cox PA. Distinguishing the cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) from other diamino acids. Toxicon 2011; 57:730-8. [PMID: 21329717 DOI: 10.1016/j.toxicon.2011.02.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 02/08/2011] [Indexed: 11/18/2022]
Abstract
β-N-methylamino-L-alanine (BMAA) is produced by diverse taxa of cyanobacteria, and has been detected by many investigators who have searched for it in cyanobacterial blooms, cultures and collections. Although BMAA is distinguishable from proteinogenic amino acids and its isomer 2,4-DAB using standard chromatographic and mass spectroscopy techniques routinely used for the analysis of amino acids, we studied whether BMAA could be reliably distinguished from other diamino acids, particularly 2,6-diaminopimelic acid which has been isolated from the cell walls of many bacterial species. We used HPLC-FD, UHPLC-UV, UHPLC-MS, and triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) to differentiate BMAA from the diamino acids 2,6-diaminopimelic acid, N-2(amino)ethylglycine, lysine, ornithine, 2,4-diaminosuccinic acid, homocystine, cystine, tryptophan, as well as other amino acids including asparagine, glutamine, and methionine methylsulfonium.
Collapse
Affiliation(s)
- S A Banack
- Institute for Ethnomedicine, Box 3464, Jackson, WY 83001, USA
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Cox PA, Richer R, Metcalf JS, Banack SA, Codd GA, Bradley WG. Cyanobacteria and BMAA exposure from desert dust: a possible link to sporadic ALS among Gulf War veterans. ACTA ACUST UNITED AC 2010; 10 Suppl 2:109-17. [PMID: 19929742 DOI: 10.3109/17482960903286066] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Veterans of the 1990-1991 Gulf War have been reported to have an increased incidence of amyotrophic lateral sclerosis (ALS) compared to personnel who were not deployed. An excess of ALS cases was diagnosed in Gulf War veterans younger than 45 years of age. Increased ALS among Gulf War veterans appears to be an outbreak time-limited to the decade following the Gulf War. Seeking to identify biologically plausible environmental exposures, we have focused on inhalation of cyanobacteria and cyanotoxins carried by dust in the Gulf region, particularly Qatar. Cyanobacterial crusts and mats are widespread in the deserts of Qatar, occupying up to 56% of the available area in some microhabitats. These cyanobacterial crusts, which help bind the desert sands, are dormant throughout most of the year, but during brief spring rains actively photosynthesize. When disturbed by vehicular traffic or other military activities, the dried crusts and mats can produce significant dust. Using HPLC/FD, an amino acid analyzer, UPLC/MS, and triple quadrupole LC/MS/MS we find that the dried crusts and mats contain neurotoxic cyanobacterial toxins, including beta-N-methylamino-L-alanine (BMAA) and 2,4 diaminobutyric acid (DAB). If dust containing cyanobacteria is inhaled, significant exposure to BMAA and other cyanotoxins may occur. We suggest that inhalation of BMAA, DAB, and other aerosolized cyanotoxins may constitute a significant risk factor for the development of ALS and other neurodegenerative diseases.
Collapse
Affiliation(s)
- Paul Alan Cox
- Institute for Ethnomedicine, Jackson Hole, Wyoming 83001-3464, USA.
| | | | | | | | | | | |
Collapse
|
37
|
|
38
|
Roney BR, Renhui L, Banack SA, Murch S, Honegger R, Cox PA. Consumption offa cai Nostocsoup: A Potential for BMAA exposure fromNostoccyanobacteria in China? ACTA ACUST UNITED AC 2009; 10 Suppl 2:44-9. [DOI: 10.3109/17482960903273031] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
39
|
|
40
|
Abstract
OBJECTIVE The aim of this study was to screen for and quantify the neurotoxic amino acid beta-N-methylamino-L-alanine (BMAA) in a cohort of autopsy specimens taken from Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and non-neurological controls. BMAA is produced by cyanobacteria found in a variety of freshwater, marine, and terrestrial habitats. The possibility of geographically broad human exposure to BMAA had been suggested by the discovery of BMAA in brain tissues of Chamorro patients with ALS/Parkinsonism dementia complex from Guam and more recently in AD patients from North America. These observations warranted an independent study of possible BMAA exposures outside of the Guam ecosystem. METHODS Postmortem brain specimens were taken from neuropathologically confirmed cases of 13 ALS, 12 AD, 8 HD patients, and 12 age-matched non-neurological controls. BMAA was quantified using a validated fluorescent HPLC method previously used to detect BMAA in patients from Guam. Tandem mass spectrometric (MS) analysis was carried out to confirm the identification of BMAA in neurological specimens. RESULTS We detected and quantified BMAA in neuroproteins from postmortem brain tissue of patients from the United States who died with sporadic AD and ALS but not HD. Incidental detections observed in two out of the 24 regions were analyzed from the controls. The concentrations of BMAA were below what had been reported previously in Chamarro ALS/ Parkinsonism dementia complex patients, but demonstrated a twofold range across disease and regional brain area comparisons. The presence of BMAA in these patients was confirmed by triple quadrupole liquid chromatography/mass spectrometry/mass spectrometry. CONCLUSIONS The occurrence of BMAA in North American ALS and AD patients suggests the possibility of a gene/environment interaction, with BMAA triggering neurodegeneration in vulnerable individuals.
Collapse
Affiliation(s)
- J Pablo
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Bradley WG, Banack SA, Cox PA. The ALS/PDC syndrome of Guam and the cycad hypothesis. Neurology 2009; 72:473-476. [PMID: 19195084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
|
42
|
Roney HC, Booth GM, Cox PA. Competitive exclusion of Cyanobacterial species in the Great Salt Lake. Extremophiles 2009; 13:355-61. [PMID: 19129967 DOI: 10.1007/s00792-008-0223-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 12/16/2008] [Indexed: 11/28/2022]
Abstract
The Great Salt Lake is separated into different salinity regimes by rail and vehicular causeways. Cyanobacterial distributions map salinity, with Aphanothece halophytica proliferating in the highly saline northern arm (27% saline), while Nodularia spumigena occurs in the less saline south (6-10%). We sought to test if cyanobacterial species abundant in the north are competitively excluded from the south, and if southern species are excluded by the high salinity of the north. Autoclaved samples from the north and south sides of each causeway were inoculated with water from each area. Aphanothece, Oscillatoria, Phormidium, and Nodularia were identified in the culture flasks using comparative differential interference contrast, fluorescence, and scanning electron microscopy. Aphanothece halophytica occurred in all inocula, but is suppressed in the presence of Nodularia spumigena. N. spumigena was found only in inocula from the less saline waters in the south, and apparently cannot survive the extremely hypersaline waters of the northern arm. These data suggest that both biotic and abiotic factors influence cyanobacterial distributions in the Great Salt Lake.
Collapse
Affiliation(s)
- Hillary C Roney
- Institute for Ethnomedicine, Box 3464, Jackson Hole, WY 83001, USA
| | | | | |
Collapse
|
43
|
Johnson HE, Banack SA, Cox PA. Variability in content of the anti-AIDS drug candidate prostratin in Samoan populations of Homalanthus nutans. J Nat Prod 2008; 71:2041-2044. [PMID: 19007283 PMCID: PMC2663895 DOI: 10.1021/np800295m] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Indexed: 05/27/2023]
Abstract
Homalanthus nutans, used by Samoan healers to treat hepatitis, produces the antiviral compound 12-deoxyphorbol 13-acetate, prostratin (1). Prostratin is being developed as an adjuvant therapy to clear latent viral reservoirs, the major obstacle to eradication of HIV-AIDS within the human body. A validated reversed-phase HPLC method was developed to assay concentrations of 1 in H. nutans. A survey of four distinct populations on two different Samoan islands revealed significant variability in content. The stem tissue (range 0.2-52.6 microg/g 1), used by healers in indigenous therapies,gave a higher median concentration of prostratin (3.5 microg/g) than root or leaf tissues (2.9 and 2.5 microg/g, respectively).The high variability and skewness of these data indicate that cultivar selection for drug production will be important for this species. The reversed-phase HPLC assay will allow plants to be selected for agricultural development and genetic analysis by identifying those individuals above and below a 95% confidence interval for the median concentration.
Collapse
Affiliation(s)
| | | | - Paul Alan Cox
- Corresponding author. Tel: (307) 734-1680. Fax: (307) 734-1810. E-mail:
| |
Collapse
|
44
|
|
45
|
Johnson HE, King SR, Banack SA, Webster C, Callanaupa WJ, Cox PA. Cyanobacteria (Nostoc commune) used as a dietary item in the Peruvian highlands produce the neurotoxic amino acid BMAA. J Ethnopharmacol 2008; 118:159-65. [PMID: 18495396 DOI: 10.1016/j.jep.2008.04.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 03/21/2008] [Accepted: 04/04/2008] [Indexed: 05/03/2023]
Abstract
In the mountains of Peru, globular colonies of Nostoc commune (Nostocales) are collected in the highland lakes by the indigenous people, who call them llullucha. They are consumed locally, traded for maize, or sold, eventually entering the folk markets of Cusco and other neighboring cities. Throughout highland Peru, Nostoc commune is highly salient as a seasonal dietary item, being eaten alone, or in picante -- a local stew -- and is said to be highly nutritious. Nostoc commune has been known to produce unusual amino acids, including those of the mycosporine group, which possibly function to prevent UV damage. We analyzed 21 different Nostoc commune spherical colonies from 7 different market collections in the Cusco area for the presence of beta-N-methylamino-L-alanine (BMAA), a neurotoxic amino acid produced by diverse taxa of cyanobacteria, using four different analytical techniques (HPLC-FD, UPLC-UV, UPLC/MS, LC/MS/MS). We found using all four techniques that BMAA was present in the samples purchased in the Peruvian markets. Since BMAA has been putatively linked to neurodegenerative illness, it would be of interest to know if the occurrence of ALS, Alzheimer's, or Parkinson's Disease is greater among individuals who consume llullucha in Peru.
Collapse
|
46
|
Abstract
By finding some important culture conditions as below, we succeeded in experimentally controlling the whole life history of a dioecious marine green alga, Bryopsis plumosa (Hudson) C. Agardh. In this study, we focused on the primary and secondary sex ratios (i.e. at inception and maturity) using these culture techniques. Gametogenesis was induced by culturing haploid gametophytes with Provasoli's enriched seawater (PES) medium under a 14:10 h light:dark cycle at 14 degrees C. Formed zygotes grew into diploid sporophytes, which were cultured for 3 months with PES medium under a 14:10 h light:nbsp;dark cycle at 18 degrees C. Then they were transferred into Schreiber medium and cultured under a 10:14 h light:dark cycle at 22 degrees C. Within 1 week, zoosporogenesis was observed. Zoospores were released within a couple of days. Each zoospore soon germinated and grew into a unisexual gametophyte. The primary sex ratio was examined in gametophytes that originated from a single sporophyte. The secondary sex ratio was studied in the field. Both were estimated as 1:1. Synchronized meiotic cell divisions might occur during zoosporogenesis dividing each sex-determining factor evenly among zoospores. Given the equal sex ratio at maturity, there seems to be no environmental factor that differentially affects the survival of male or female gametophytes in nature.
Collapse
Affiliation(s)
- Tatsuya Togashi
- Marine Biosystems Research Center, Chiba University, Kamogawa 299-5502, Japan.
| | | |
Collapse
|
47
|
Metcalf JS, Banack SA, Lindsay J, Morrison LF, Cox PA, Codd GA. Co-occurrence of β-N-methylamino-l-alanine, a neurotoxic amino acid with other cyanobacterial toxins in British waterbodies, 1990–2004. Environ Microbiol 2008; 10:702-8. [PMID: 18237305 DOI: 10.1111/j.1462-2920.2007.01492.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- James S Metcalf
- Division of Molecular and Environmental Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 4HN, UK.
| | | | | | | | | | | |
Collapse
|
48
|
Abstract
Diverse species of cyanobacteria have recently been discovered to produce the neurotoxic non-protein amino acid β-methylamino-L-alanine (BMAA). In Guam, BMAA has been studied as a possible environmental toxin in the diets of indigenous Chamorro people known to have high levels of Amyotrophic Lateral Sclerosis/ Parkinsonism Dementia Complex (ALS/PDC). BMAA has been found to accumulate in brain tissues of patients with progressive neurodegenerative illness in North America. In Guam, BMAA was found to be produced by endosymbiotic cyanobacteria of the genus Nostoc which live in specialized cycad roots. We here report detection of BMAA in laboratory cultures of a free-living marine species of Nostoc. We successfully detected BMAA in this marine species of Nostoc with five different methods: HPLC-FD, UPLC-UV, Amino Acid Analyzer, LC/MS, and Triple Quadrupole LC/MS/MS. This consensus of five different analytical methods unequivocally demonstrates the presence of BMAA in this marine cyanobacterium. Since protein-associated BMAA can accumulate in increasing levels within food chains, it is possible that biomagnification of BMAA could occur in marine ecosystems similar to the biomagnification of BMAA in terrestrial ecosystems. Production of BMAA by marine cyanobacteria may represent another route of human exposure to BMAA. Since BMAA at low concentrations causes the death of motor neurons, low levels of BMAA exposure may trigger motor neuron disease in genetically vulnerable individuals.
Collapse
Affiliation(s)
- Sandra Anne Banack
- Institute for Ethnomedicine, Box 3464, Jackson Hole, Wyoming 83001, USA; E-mails:
(Sandra Anne Banack);
(Holly E. Johnson);
(Ran Cheng)
- Department of Biological Science, California State University, Fullerton, California 92834, USA
| | - Holly E. Johnson
- Institute for Ethnomedicine, Box 3464, Jackson Hole, Wyoming 83001, USA; E-mails:
(Sandra Anne Banack);
(Holly E. Johnson);
(Ran Cheng)
| | - Ran Cheng
- Institute for Ethnomedicine, Box 3464, Jackson Hole, Wyoming 83001, USA; E-mails:
(Sandra Anne Banack);
(Holly E. Johnson);
(Ran Cheng)
| | - Paul Alan Cox
- Institute for Ethnomedicine, Box 3464, Jackson Hole, Wyoming 83001, USA; E-mails:
(Sandra Anne Banack);
(Holly E. Johnson);
(Ran Cheng)
- * Author to whom correspondence should be addressed; E-mail:
| |
Collapse
|
49
|
|
50
|
Togashi T, Cox PA, Bartelt JL. Underwater fertilization dynamics of marine green algae. Math Biosci 2007; 209:205-21. [PMID: 17331549 DOI: 10.1016/j.mbs.2006.08.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Revised: 03/20/2006] [Accepted: 08/29/2006] [Indexed: 10/24/2022]
Abstract
We studied the fertilization dynamics of marine green algae with both analytical methods and numerical simulations. In this study, we focused on a new factor, gametic investment per unit volume of the space in which gametes searched for their partners, and compared the numbers of zygotes formed at lower investments with those at higher investments. As a function of the gametic investment for various anisogamy ratios, we found there was generally a crossover region for each series where, for gametic investments larger than the crossover region, isogamy prevailed with the highest number of zygotes formed, while for gametic investments smaller than the crossover region, anisogamy dominated. These results may explain both the stable maintenance of isogamy in shallow water and the distribution of anisogamous species in deep water, since in shallow water the gametic investments typically exceed this crossover region and vice versa. Comparisons of field data from marine green algae are consistent with this hypothesis. Also, we showed that the cost of sex was approximately twofold in zygote formation when comparing isogamous species with mating types to those without mating types.
Collapse
Affiliation(s)
- Tatsuya Togashi
- Marine Biosystems Research Center, Chiba University, Kamogawa 299-5502, Japan.
| | | | | |
Collapse
|