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He H, Bertin MJ, Wu S, Wahome PG, Beauchesne KR, Youngs RO, Zimba PV, Moeller PDR, Sauri J, Carter GT. Cyanobufalins: Cardioactive Toxins from Cyanobacterial Blooms. J Nat Prod 2018; 81:2576-2581. [PMID: 30369239 DOI: 10.1021/acs.jnatprod.8b00736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cyanobufalins A-C (1-3), a new series of cardiotoxic steroids, have been discovered from cyanobacterial blooms in Buckeye Lake and Grand Lake St. Marys in Ohio. Compounds 1-3 contain distinctive structural features, including geminal methyl groups at C-4, a 7,8 double bond, and a C-16 chlorine substituent that distinguish them from plant- or animal-derived congeners. Despite these structural differences, the compounds are qualitatively identical to bufalin in their cytotoxic profiles versus cell lines in tissue culture and cardiac activity, as demonstrated in an impedance-based cellular assay conducted with IPSC-derived cardiomyocytes. Cyanobufalins are nonselectively toxic to human cells in the single-digit nanomolar range and show stimulation of contractility in cardiomyocytes at sub-nanomolar concentrations. The estimated combined concentration of 1-3 in the environment is in the same nanomolar range, and consequently more precise quantitative analyses are recommended along with more detailed cardiotoxicity studies. This is the first time that cardioactive steroid toxins have been found associated with microorganisms in an aquatic environment. Several factors point to a microbial biosynthetic origin for the cyanobufalins.
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Affiliation(s)
- Haiyin He
- Biosortia Pharmaceuticals , Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Matthew J Bertin
- Biosortia Pharmaceuticals , Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy , University of Rhode Island , Kingston , Rhode Island 02881 , United States
| | - ShiBiao Wu
- Biosortia Pharmaceuticals , Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Paul G Wahome
- Biosortia Pharmaceuticals , Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Kevin R Beauchesne
- Biosortia Pharmaceuticals , Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Ross O Youngs
- Biosortia Pharmaceuticals , Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Paul V Zimba
- Center for Coastal Studies , Texas A & M University Corpus Christi , 6300 Ocean Drive , Corpus Christi , Texas 78412 , United States
| | - Peter D R Moeller
- National Oceanic and Atmospheric Administration , Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Josep Sauri
- Structure Elucidation, Analytical Research & Development , Merck & Co., Inc. , 126 E. Lincoln Avenue , Rahway , New Jersey 07735 , United States
| | - Guy T Carter
- Biosortia Pharmaceuticals , Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
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He H, Wu S, Wahome PG, Bertin MJ, Pedone AC, Beauchesne KR, Moeller PDR, Carter GT. Microcystins Containing Doubly Homologated Tyrosine Residues from a Microcystis aeruginosa Bloom: Structures and Cytotoxicity. J Nat Prod 2018; 81:1368-1375. [PMID: 29847132 DOI: 10.1021/acs.jnatprod.7b00986] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Four new microcystin congeners are described including the first three examples of microcystins containing the rare doubly homologated tyrosine residue 2-amino-5-(4-hydroxyphenyl)pentanoic acid (Ahppa) (1-4). Large-scale harvesting and biomass processing allowed the isolation of substantial quantities of these compounds, thus enabling complete structure determination by NMR as well as cytotoxicity evaluation against selected cancer cell lines. The new Ahppa-toxins all incorporate Ahppa residues at the 2-position, and one of these also has a second Ahppa at position 4. The two most lipophilic Ahppa-containing microcystins showed 10-fold greater cytotoxic potency against human tumor cell lines (A549 and HCT-116) compared to microcystin-LR (5). The presence of an Ahppa residue in microcystin congeners is difficult to ascertain by MS methods alone, due to the lack of characteristic fragment ions derived from the doubly homologated side chain. Owing to their unexpected cytotoxic potency, the potential impact of the compounds on human health should be further evaluated.
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Affiliation(s)
- Haiyin He
- Biosortia Pharmaceuticals, Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - ShiBiao Wu
- Biosortia Pharmaceuticals, Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Paul G Wahome
- Biosortia Pharmaceuticals, Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Matthew J Bertin
- Biosortia Pharmaceuticals, Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Anna C Pedone
- Biosortia Pharmaceuticals, Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Kevin R Beauchesne
- Biosortia Pharmaceuticals, Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Peter D R Moeller
- National Oceanic and Atmospheric Administration, Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
| | - Guy T Carter
- Biosortia Pharmaceuticals, Hollings Marine Laboratory , 331 Ft. Johnson Road , Charleston , South Carolina 29412 , United States
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Belisle RS, Via CW, Schock TB, Villareal TA, Zimba PV, Beauchesne KR, Moeller PDR, Bertin MJ. Trichothiazole A, a dichlorinated polyketide containing an embedded thiazole isolated from Trichodesmium blooms. Tetrahedron Lett 2017; 58:4066-4068. [PMID: 32189813 PMCID: PMC7079771 DOI: 10.1016/j.tetlet.2017.09.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mass spectrometry-guided isolation of the lipophilic extract of Trichodesmium bloom material led to the isolation and structure characterization of a new thiazole-containing di-chlorinated polyketide (1). The structure of 1 was deduced using 1D and 2D NMR analysis, high-resolution mass spectrometry analysis and complementary spectroscopic procedures. Trichothiazole A possesses interesting structural features, such as a terminal alkyne, two vinyl chlorides and a 2,4-disubstituted thiazole. Trichothiazole A showed moderate cytotoxicity to Neuro-2A cells (EC50: 13.3 ± 1.1 μM).
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Affiliation(s)
- Richard S. Belisle
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, United States
| | - Christopher W. Via
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, United States
| | - Tracey B. Schock
- National Institutes of Standards and Technology, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States
| | - Tracy A. Villareal
- Marine Science Institute, University of Texas at Austin, 750 Channel View Drive, Port Aransas, Texas 78373, United States
| | - Paul V. Zimba
- Center for Coastal Studies and Department of Life Sciences, Texas A&M, Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, United States
| | - Kevin R. Beauchesne
- Emerging Toxins Program, National Ocean Service/NOAA, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States
| | - Peter D. R. Moeller
- Emerging Toxins Program, National Ocean Service/NOAA, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States
| | - Matthew J. Bertin
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, United States
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Work TM, Moeller PDR, Beauchesne KR, Dagenais J, Breeden R, Rameyer R, Walsh WJ, Abecassis M, Kobayashi DR, Conway C, Winton J. Pufferfish mortality associated with novel polar marine toxins in Hawaii. Dis Aquat Organ 2017; 123:87-99. [PMID: 28262632 DOI: 10.3354/dao03096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Fish die-offs are important signals in tropical marine ecosystems. In 2010, a mass mortality of pufferfish in Hawaii (USA) was dominated by Arothron hispidus showing aberrant neurological behaviors. Using pathology, toxinology, and field surveys, we implicated a series of novel, polar, marine toxins as a likely cause of this mass mortality. Our findings are striking in that (1) a marine toxin was associated with a kill of a fish species that is itself toxic; (2) we provide a plausible mechanism to explain clinical signs of affected fish; and (3) this epizootic likely depleted puffer populations. Whilst our data are compelling, we did not synthesize the toxin de novo, and we were unable to categorically prove that the polar toxins caused mortality or that they were metabolites of an undefined parent compound. However, our approach does provide a template for marine fish kill investigations associated with marine toxins and inherent limitations of existing methods. Our study also highlights the need for more rapid and cost-effective tools to identify new marine toxins, particularly small, highly polar molecules.
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Affiliation(s)
- Thierry M Work
- US Geological Survey, National Wildlife Health Center-Honolulu Field Station, Honolulu, HI 96850, USA
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Gummadidala PM, Chen YP, Beauchesne KR, Miller KP, Mitra C, Banaszek N, Velez-Martinez M, Moeller PDR, Ferry JL, Decho AW, Chanda A. Aflatoxin-Exposure of Vibrio gazogenes as a Novel System for the Generation of Aflatoxin Synthesis Inhibitors. Front Microbiol 2016; 7:814. [PMID: 27375561 PMCID: PMC4891353 DOI: 10.3389/fmicb.2016.00814] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [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: 02/23/2016] [Accepted: 05/13/2016] [Indexed: 01/09/2023] Open
Abstract
Aflatoxin is a mycotoxin and a secondary metabolite, and the most potent known liver carcinogen that contaminates several important crops, and represents a significant threat to public health and the economy. Available approaches reported thus far have been insufficient to eliminate this threat, and therefore provide the rational to explore novel methods for preventing aflatoxin accumulation in the environment. Many terrestrial plants and microbes that share ecological niches and encounter the aflatoxin producers have the ability to synthesize compounds that inhibit aflatoxin synthesis. However, reports of natural aflatoxin inhibitors from marine ecosystem components that do not share ecological niches with the aflatoxin producers are rare. Here, we show that a non-pathogenic marine bacterium, Vibrio gazogenes, when exposed to low non-toxic doses of aflatoxin B1, demonstrates a shift in its metabolic output and synthesizes a metabolite fraction that inhibits aflatoxin synthesis without affecting hyphal growth in the model aflatoxin producer, Aspergillus parasiticus. The molecular mass of the predominant metabolite in this fraction was also different from the known prodigiosins, which are the known antifungal secondary metabolites synthesized by this Vibrio. Gene expression analyses using RT-PCR demonstrate that this metabolite fraction inhibits aflatoxin synthesis by down-regulating the expression of early-, middle-, and late- growth stage aflatoxin genes, the aflatoxin pathway regulator, aflR and one global regulator of secondary metabolism, laeA. Our study establishes a novel system for generation of aflatoxin synthesis inhibitors, and emphasizes the potential of the under-explored Vibrio’s silent genome for generating new modulators of fungal secondary metabolism.
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Affiliation(s)
- Phani M Gummadidala
- Department of Environmental Health Science, Arnold School of Public Health, University of South Carolina, Columbia SC, USA
| | - Yung Pin Chen
- Department of Environmental Health Science, Arnold School of Public Health, University of South Carolina, Columbia SC, USA
| | | | - Kristen P Miller
- Department of Environmental Health Science, Arnold School of Public Health, University of South Carolina, Columbia SC, USA
| | - Chandrani Mitra
- Department of Environmental Health Science, Arnold School of Public Health, University of South Carolina, Columbia SC, USA
| | - Nora Banaszek
- Department of Environmental Health Science, Arnold School of Public Health, University of South Carolina, Columbia SC, USA
| | - Michelle Velez-Martinez
- Department of Environmental Health Science, Arnold School of Public Health, University of South Carolina, Columbia SC, USA
| | - Peter D R Moeller
- National Ocean Service, Hollings Marine Laboratory, Charleston SC, USA
| | - John L Ferry
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia SC, USA
| | - Alan W Decho
- Department of Environmental Health Science, Arnold School of Public Health, University of South Carolina, Columbia SC, USA
| | - Anindya Chanda
- Department of Environmental Health Science, Arnold School of Public Health, University of South Carolina, Columbia SC, USA
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Bagwell CE, Abernathy A, Barnwell R, Milliken CE, Noble PA, Dale T, Beauchesne KR, Moeller PDR. Discovery of Bioactive Metabolites in Biofuel Microalgae That Offer Protection against Predatory Bacteria. Front Microbiol 2016; 7:516. [PMID: 27148205 PMCID: PMC4834574 DOI: 10.3389/fmicb.2016.00516] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [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: 01/15/2016] [Accepted: 03/29/2016] [Indexed: 12/19/2022] Open
Abstract
Microalgae could become an important resource for addressing increasing global demand for food, energy, and commodities while helping to reduce atmospheric greenhouse gasses. Even though Chlorophytes are generally regarded safe for human consumption, there is still much we do not understand about the metabolic and biochemical potential of microscopic algae. The aim of this study was to evaluate biofuel candidate strains of Chlorella and Scenedesmus for the potential to produce bioactive metabolites when grown under nutrient depletion regimes intended to stimulate production of triacylglycerides. Strain specific combinations of macro- and micro-nutrient restricted growth media did stimulate neutral lipid accumulation by microalgal cultures. However, cultures that were restricted for iron consistently and reliably tested positive for cytotoxicity by in vivo bioassays. The addition of iron back to these cultures resulted in the disappearance of the bioactive components by LC/MS fingerprinting and loss of cytotoxicity by in vivo bioassay. Incomplete NMR characterization of the most abundant cytotoxic fractions suggested that small molecular weight peptides and glycosides could be responsible for Chlorella cytotoxicity. Experiments were conducted to determine if the bioactive metabolites induced by Fe-limitation in Chlorella sp. cultures would elicit protection against Vampirovibrio chlorellavorus, an obligate predator of Chlorella. Introduction of V. chlorellavorus resulted in a 72% decrease in algal biomass in the experimental controls after 7 days. Conversely, only slight losses of algal biomass were measured for the iron limited Chlorella cultures (0–9%). This study demonstrates a causal linkage between iron bioavailability and bioactive metabolite production in strains of Chlorella and Scenedesmus. Further study of this phenomenon could contribute to the development of new strategies to extend algal production cycles in open, outdoor systems while ensuring the protection of biomass from predatory losses.
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Affiliation(s)
- Christopher E Bagwell
- Environmental Sciences and Biotechnology, Savannah River National Laboratory, Aiken SC, USA
| | - Amanda Abernathy
- Environmental Sciences and Biotechnology, Savannah River National Laboratory, Aiken SC, USA
| | - Remy Barnwell
- Environmental Sciences and Biotechnology, Savannah River National Laboratory, Aiken SC, USA
| | - Charles E Milliken
- Environmental Sciences and Biotechnology, Savannah River National Laboratory, Aiken SC, USA
| | - Peter A Noble
- Department of Biological Sciences, Alabama State University, Montgomery AL, USA
| | - Taraka Dale
- Bioscience Division, Los Alamos National Laboratory, Los Alamos NM, USA
| | - Kevin R Beauchesne
- National Oceanic and Atmospheric Administration/National Centers for Coastal Ocean Science's Center for Human Health Research Hollings Marine Laboratory, Charleston SC, USA
| | - Peter D R Moeller
- National Oceanic and Atmospheric Administration/National Centers for Coastal Ocean Science's Center for Human Health Research Hollings Marine Laboratory, Charleston SC, USA
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Schock TB, Huncik K, Beauchesne KR, Villareal TA, Moeller PDR. Identification of trichotoxin, a novel chlorinated compound associated with the bloom forming Cyanobacterium, Trichodesmium thiebautii. Environ Sci Technol 2011; 45:7503-7509. [PMID: 21740025 DOI: 10.1021/es201034r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Trichodesmium is a suspected toxin-producing nonheterocystous cyanobacteria ubiquitous in tropical, subtropical, and temperate seas. The genus is known for its ability to fix nitrogen and form massive blooms. In oligotrophic seas, it can dominate the biomass and be a major component of oceanic primary production and global nitrogen cycling. Numerous reports suggest Trichodesmium-derived toxins are a cause of death of fish, crabs, and bivalves. Laboratory studies have demonstrated neurotoxic effects in T. thiebautii cell extracts and field reports suggest respiratory distress and contact dermatitis of humans at collection sites. However, Trichodesmium toxins have not been identified and characterized. Here, we report the extraction of a lipophilic toxin from field-collected T. thiebautii using a purification method of several chromatographic techniques, nuclear magnetic resonance (NMR), mass spectroscopy (MS), and Fourier transformed-infrared spectroscopy (FT-IR). Trichotoxin has a molecular formula of C(20)H(27)ClO and a mass of 318 m/z and possesses cytotoxic activity against GH(4)C(1) rat pituitary and Neuro-2a mouse neuroblastoma cells. A detection method using liquid chromatography/mass spectrometry (LC/MS) was developed. This compound is the first reported cytotoxic natural product isolated and fully characterized from a Trichodesmium species.
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Affiliation(s)
- Tracey B Schock
- Department of Marine Biomedicine and Environmental Sciences, Medical University of South Carolina, Charleston, South Carolina 29425, United States
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Moeller PDR, Beauchesne KR, Huncik KM, Davis WC, Christopher SJ, Riggs-Gelasco P, Gelasco AK. Metal complexes and free radical toxins produced by Pfiesteria piscicida. Environ Sci Technol 2007; 41:1166-72. [PMID: 17598275 DOI: 10.1021/es0617993] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Metal-containing organic toxins produced by Pfiesteria piscicida were characterized, for the first time, by corroborating data obtained from five distinct instrumental methods: nuclear magnetic resonance spectroscopy (NMR), inductively coupled plasma mass spectrometry (ICP-MS), liquid chromatography particle beam glow discharge mass spectrometry (LC/PB-G DMS), electron paramagnetic resonance spectroscopy (EPR), and X-ray absorption spectroscopy (XAS). The high toxicity of the metal-containing toxins is due to metal-mediated free radical production. This mode of activity explains the toxicity of Pfiesteria, as well as previously reported difficulty in observing the molecular target, due to the ephemeral nature of radical species. The toxins are highly labile in purified form, maintaining activity for only 2-5 days before all activity is lost. The multiple toxin congeners in active extracts are also susceptible to decomposition in the presence of white light, pH variations, and prolonged heat. These findings represent the first formal isolation and characterization of a radical forming toxic organic-ligated metal complex isolated from estuarine/marine dinoflagellates. These findings add to an increased understanding regarding the active role of metals interacting with biological systems in the estuarine environment, as well as their links and implications to human health.
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Affiliation(s)
- Peter D R Moeller
- Center for Coastal Environmental Health and Biomolecular Research, National Oceanic and Atmospheric Administration National Ocean Service, Hollings Marine Laboratory, Charleston, South Carolina 29412, USA.
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