1
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Pesek JJ, Matyska MT, Hiltz T, McCall J. Application of a Cholesterol-Based Stationary Phase for the Analysis of Brevetoxins. J Sep Sci 2023; 46:e2200666. [PMID: 36369995 DOI: 10.1002/jssc.202200666] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/20/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
A high-performance liquid chromatography protocol for the analysis of brevetoxins has been developed using a silica hydride-based cholesterol column. Brevetoxins are neurotoxins produced by harmful algae that have additional potential as drugs for a number of illnesses/diseases. To develop the optimum conditions, a number of different experimental approaches were tested. These include isocratic and gradient elution, different organic mobile phase components, and temperature variations. A separate protocol was developed for the compounds brevenal and brevenol, also produced by the same algae that make brevetoxins. Brevenal is a natural product under investigation as a therapy for chronic respiratory diseases, such as cystic fibrosis or asthma. The goal of this study was to provide a protocol for the analysis of these compounds that could be further developed into a validated method depending on a particular laboratory's capabilities and to highlight some of the unique features of the cholesterol stationary phase.
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Affiliation(s)
- Joseph J Pesek
- Department of Chemistry, San Jose State University, San Jose, California, USA
| | - Maria T Matyska
- Department of Chemistry, San Jose State University, San Jose, California, USA
| | - Tanya Hiltz
- MicroSolv Technology Corporation, Leland, North Carolina, USA
| | - Jennifer McCall
- University of North Carolina Wilmington, College of Health and Human Services, Wilmington, North Carolina, USA
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2
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Zhou M, Mathew S, de Bruin B. Thermal and (Thermo-Reversible) Photochemical Cycloisomerization of 1 H-2-Benzo[ c]oxocins: From Synthetic Applications to the Development of a New T-Type Molecular Photoswitch. J Am Chem Soc 2022; 145:645-657. [PMID: 36548378 PMCID: PMC9837851 DOI: 10.1021/jacs.2c11310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A novel T-type molecular photoswitch based on the reversible cyclization of 1H-2-benzo[c]oxocins to dihydro-4H-cyclobuta[c]isochromenes has been developed. The switching mechanism involves a light-triggered ring-contraction of 8-membered 1H-2-benzo[c]oxocins to 4,6-fused O-heterocyclic dihydro-4H-cyclobuta[c]isochromene ring systems, with reversion back to the 1H-2-benzo[c]oxocin state accessible through heating. Both processes are unidirectional and proceed with good efficiency, with switching properties─including reversibility and half-life time─easily adjusted via structural functionalization. Our new molecular-switching platform exhibits independence from solvent polarity, originating from its neutral-charge switching mechanism, a property highly sought-after for biological applications. The photoinduced ring-contraction involves a [2+2] conjugated-diene cyclization that obeys the Woodward-Hoffmann rules. In contrast, the reverse process initiates via a thermal ring-opening (T > 60 °C) to produce the original 8-membered 1H-2-benzo[c]oxocins, which is thermally forbidden according to the Woodward-Hoffmann rules. The thermal ring-opening is likely to proceed via an ortho-quinodimethane (o-QDM) intermediate, and the corresponding switching mechanisms are supported by experimental observations and density functional theory calculations. Other transformations of 1H-2-benzo[c]oxocins were found upon altering reaction conditions: prolonged heating of the 1H-2-benzo[c]oxocins at a significantly elevated temperature (72 h at 120 °C), with the resulting dihydronaphthalenes formed via the o-QDM intermediate. These reactions also proceed with good chemoselectivities, providing new synthetic protocols for motifs found in several bioactive molecules, but are otherwise difficult to access.
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3
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Sakai T, Takenaka R, Koike Y, Hira A, Mori Y. <i>p</i>-Methoxy- and 2,4-Dimethoxybenzyl <i>N</i>-Acetylcarbamate Potassium Salts: Versatile Reagents for <i>N</i>-Alkylacetamide and <i>p</i>-Methoxy- and 2,4-Dimethoxybenzyl Carbamates. Chem Pharm Bull (Tokyo) 2022; 70:650-661. [DOI: 10.1248/cpb.c22-00413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | | | | | | | - Yuji Mori
- Faculty of Pharmacy, Meijo University
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4
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McCall JR, Sausman KT, Keeler DM, Brown AP, Turrise SL. Immune Modulating Brevetoxins: Monocyte Cytotoxicity, Apoptosis, and Activation of M1/M2 Response Elements Is Dependent on Reactive Groups. Mar Drugs 2022; 20:md20040233. [PMID: 35447906 PMCID: PMC9031394 DOI: 10.3390/md20040233] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/24/2022] [Accepted: 03/27/2022] [Indexed: 12/03/2022] Open
Abstract
Brevetoxins are a suite of marine neurotoxins that activate voltage-gated sodium channels (VGSCs) in cell membranes, with toxicity occurring from persistent activation of the channel at high doses. Lower doses, in contrast, have been shown to elicit neuroregeneration. Brevetoxins have thus been proposed as a novel treatment for patients after stroke, when neuron regrowth and repair is critical to recovery. However, findings from environmental exposures indicate that brevetoxins may cause inflammation, thus, there is concern for brevetoxins as a stroke therapy given the potential for neuroinflammation. In this study, we examined the inflammatory properties of several brevetoxin analogs, including those that do and do not bind strongly to VGSCs, as binding has classically indicated toxicity. We found that several analogs are toxic to monocytes, while others are not, and the degree of toxicity is not directly related to VGSC binding. Rather, results indicate that brevetoxins containing aldehyde groups were more likely to cause immunotoxicity, regardless of binding affinity to the VGSC. Our results demonstrate that different brevetoxin family members can elicit a spectrum of apoptosis and necrosis by multiple possible mechanisms of action in monocytes. As such, care should be taken in treating “brevetoxins” as a uniform group, particularly in stroke therapy research.
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Affiliation(s)
- Jennifer R. McCall
- School of Nursing, College of Health and Human Services, University of North Carolina Wilmington, Wilmington, NC 28403, USA; (K.T.S.); (A.P.B.); (S.L.T.)
- Correspondence:
| | - Kathryn T. Sausman
- School of Nursing, College of Health and Human Services, University of North Carolina Wilmington, Wilmington, NC 28403, USA; (K.T.S.); (A.P.B.); (S.L.T.)
| | | | - Ariel P. Brown
- School of Nursing, College of Health and Human Services, University of North Carolina Wilmington, Wilmington, NC 28403, USA; (K.T.S.); (A.P.B.); (S.L.T.)
| | - Stephanie L. Turrise
- School of Nursing, College of Health and Human Services, University of North Carolina Wilmington, Wilmington, NC 28403, USA; (K.T.S.); (A.P.B.); (S.L.T.)
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5
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Zhou M, Wolzak LA, Li Z, de Zwart FJ, Mathew S, de Bruin B. Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers. J Am Chem Soc 2021; 143:20501-20512. [PMID: 34802239 PMCID: PMC8662738 DOI: 10.1021/jacs.1c10927] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Indexed: 12/30/2022]
Abstract
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
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Affiliation(s)
- Minghui Zhou
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Lukas A. Wolzak
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Zirui Li
- Department
of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333
CC Leiden, The Netherlands
| | - Felix J. de Zwart
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Simon Mathew
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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6
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Hort V, Abadie E, Arnich N, Dechraoui Bottein MY, Amzil Z. Chemodiversity of Brevetoxins and Other Potentially Toxic Metabolites Produced by Karenia spp. and Their Metabolic Products in Marine Organisms. Mar Drugs 2021; 19:656. [PMID: 34940655 PMCID: PMC8709462 DOI: 10.3390/md19120656] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 12/14/2022] Open
Abstract
In recent decades, more than 130 potentially toxic metabolites originating from dinoflagellate species belonging to the genus Karenia or metabolized by marine organisms have been described. These metabolites include the well-known and large group of brevetoxins (BTXs), responsible for foodborne neurotoxic shellfish poisoning (NSP) and airborne respiratory symptoms in humans. Karenia spp. also produce brevenal, brevisamide and metabolites belonging to the hemi-brevetoxin, brevisin, tamulamide, gymnocin, gymnodimine, brevisulcenal and brevisulcatic acid groups. In this review, we summarize the available knowledge in the literature since 1977 on these various identified metabolites, whether they are produced directly by the producer organisms or biotransformed in marine organisms. Their structures and physicochemical properties are presented and discussed. Among future avenues of research, we highlight the need for more toxin occurrence data with analytical techniques, which can specifically determine the analogs present in samples. New metabolites have yet to be fully described, especially the groups of metabolites discovered in the last two decades (e.g tamulamides). Lastly, this work clarifies the different nomenclatures used in the literature and should help to harmonize practices in the future.
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Affiliation(s)
- Vincent Hort
- Laboratory for Food Safety, Pesticides and Marine Biotoxins Unit, ANSES (French Agency for Food, Environmental and Occupational Health and Safety), 94701 Maisons-Alfort, France
| | - Eric Abadie
- MARBEC (MARine Biodiversity, Exploitation and Conservation), Université de Montpellier, CNRS, Ifremer, IRD, 34200 Sète, France;
| | - Nathalie Arnich
- Risk Assessment Directorate, ANSES (French Agency for Food, Environmental and Occupational Health and Safety), 94701 Maisons-Alfort, France;
| | - Marie-Yasmine Dechraoui Bottein
- Université Côte d’Azur, CNRS, UMR 7035 ECOSEAS, 06103 Nice, France;
- Federative Research Institute—Marine Ressources, Université Côte d’Azur, CNRS, 06108 Nice, France
| | - Zouher Amzil
- Ifremer (French Research Institute for Exploitation of the Sea), 44311 Nantes, France
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7
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Shen H, Song X, Zhang Y, Zhang P, Li J, Song W, Yu Z. Profiling of Brevetoxin Metabolites Produced by Karenia brevis 165 Based on Liquid Chromatography-Mass Spectrometry. Toxins (Basel) 2021; 13:toxins13050354. [PMID: 34069292 PMCID: PMC8156667 DOI: 10.3390/toxins13050354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/09/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022] Open
Abstract
In this study, Karenia brevis 165 (K. brevis 165), a Chinese strain, was used to research brevetoxin (BTX) metabolites. The sample pretreatment method for the enrichment of BTX metabolites in an algal culture medium was improved here. The method for screening and identifying intracellular and extracellular BTX metabolites was established based on liquid chromatography-time-of-flight mass spectrometry (LC-ToF-MS) and liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS). The results show that the recovery rates for BTX toxins enriched by a hydrophilic–lipophilic balance (HLB) extraction column were higher than those with a C18 extraction column. This method was used to analyze the profiles of extracellular and intracellular BTX metabolites at different growth stages of K. brevis 165. This is the first time a Chinese strain of K. brevis has been reported that can produce toxic BTX metabolites. Five and eight kinds of BTX toxin metabolites were detected in the cell and culture media of K. brevis 165, respectively. Brevenal, a toxic BTX metabolite antagonist, was found for the first time in the culture media. The toxic BTX metabolites and brevenal in the K. brevis 165 cell and culture media were found to be fully proven in terms of the necessity of establishing a method for screening and identifying toxic BTX metabolites. The results found by qualitatively and quantitatively analyzing BTX metabolites produced by K. brevis 165 at different growth stages show that the total toxic BTX metabolite contents in single cells ranged between 6.78 and 21.53 pg/cell, and the total toxin concentration in culture media ranged between 10.27 and 449.11 μg/L. There were significant differences in the types and contents of toxic BTX metabolites with varying growth stages. Therefore, when harmful algal blooms occur, the accurate determination of BTX metabolite types and concentrations will be helpful to assess the ecological disaster risk in order to avoid hazards and provide appropriate disaster warnings.
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Affiliation(s)
- Huihui Shen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiuxian Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Correspondence:
| | - Yue Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Peipei Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Weijia Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiming Yu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (H.S.); (Y.Z.); (P.Z.); (J.L.); (W.S.); (Z.Y.)
- Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
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8
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Kelley EH, Jamison TF. Synthesis of the EFG Framework of Tamulamides A and B. Org Lett 2019; 21:8027-8030. [PMID: 31523969 PMCID: PMC6778004 DOI: 10.1021/acs.orglett.9b03015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthesis of the fused polycyclic ether motif comprising the EFG rings of the marine ladder polyethers tamulamides A and B has been achieved via two different etherification strategies. Ultimately, a reductive etherification approach proved most successful due to tolerance of the G ring substitution and provided the EFG 6,7,6 ring system in 58% yield.
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Affiliation(s)
- Elizabeth H Kelley
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Timothy F Jamison
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
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9
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Elustondo F, Chintalapudi V, Clark JS. A Short Sequence for the Iterative Synthesis of Fused Polyethers. Helv Chim Acta 2019. [DOI: 10.1002/hlca.201900161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Frédéric Elustondo
- School of ChemistryUniversity of Nottingham, University Park Nottingham NG7 2RD United Kingdom
| | - Venkaiah Chintalapudi
- School of Chemistry, Joseph Black BuildingUniversity of Glasgow, University Avenue Glasgow G12 8QQ United Kingdom
| | - J. Stephen Clark
- School of Chemistry, Joseph Black BuildingUniversity of Glasgow, University Avenue Glasgow G12 8QQ United Kingdom
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10
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Keeler DM, Grandal MK, McCall JR. Brevenal, a Marine Natural Product, is Anti-Inflammatory and an Immunomodulator of Macrophage and Lung Epithelial Cells. Mar Drugs 2019; 17:md17030184. [PMID: 30897777 PMCID: PMC6470468 DOI: 10.3390/md17030184] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/14/2019] [Accepted: 03/17/2019] [Indexed: 12/13/2022] Open
Abstract
Chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD), cystic fibrosis, and asthma, are some of the leading causes of illness and fatalities worldwide. The search for novel treatments led to the exploration of marine natural products as drug candidates to combat the debilitating effects of mucus accumulation and chronic inflammation. Previous research showed that an alga-derived compound, brevenal, could attenuate the effects of inflammatory agents, but the mechanisms by which it exerted its effects remained unclear. We investigated the effects of brevenal on lipopolysaccharide (LPS) induced cytokine/chemokine production from murine macrophages and human lung epithelial cells. It was found that brevenal reduces proinflammatory mediator secretion while preserving anti-inflammatory secretion from these cells. Furthermore, we found that brevenal does not alter cell surface Toll-like receptor 4 (TLR4) expression, thereby maintaining the cells' ability to respond to bacterial infection. However, brevenal does alter macrophage activation states, as demonstrated by reduced expression of both M1 and M2 phenotype markers, indicating this putative anti-inflammatory drug shifts innate immune cells to a less active state. Such a mechanism of action would be ideal for reducing inflammation in the lung, especially with patients suffering from chronic respiratory diseases, where inflammation can be lethal.
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Affiliation(s)
- Devon M Keeler
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
| | - Meghan K Grandal
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
| | - Jennifer R McCall
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
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11
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Oishi T. Design and Synthesis of Artificial Ladder-Shaped Polyethers for Exploring Biological Functions. HETEROCYCLES 2019. [DOI: 10.3987/rev-18-sr(f)1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Kelley EH, Jamison TF. Synthesis of the ABC framework of tamulamides A and B. Bioorg Med Chem 2018; 26:5327-5335. [PMID: 29729986 DOI: 10.1016/j.bmc.2018.04.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/19/2018] [Accepted: 04/20/2018] [Indexed: 11/29/2022]
Abstract
Synthesis of the fused tetrahydrofuran motif comprising the ABC rings of the marine ladder polyethers tamulamides A and B has been achieved via two different polyepoxide cascade strategies. Investigations into a triepoxide cascade under aqueous conditions revealed the importance of the electronic nature of the cascade end-group with this initial approach. Ultimately, a diepoxide cascade under basic conditions proved most successful, providing the ABC tetrahydropyran triad in 41% yield.
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Affiliation(s)
- Elizabeth H Kelley
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, United States
| | - Timothy F Jamison
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, United States.
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13
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Van Dolah FM, Kohli GS, Morey JS, Murray SA. Both modular and single-domain Type I polyketide synthases are expressed in the brevetoxin-producing dinoflagellate, Karenia brevis (Dinophyceae). JOURNAL OF PHYCOLOGY 2017; 53:1325-1339. [PMID: 28949419 PMCID: PMC5725682 DOI: 10.1111/jpy.12586] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 09/14/2017] [Indexed: 05/09/2023]
Abstract
Dinoflagellates are prolific producers of polyketide compounds, many of which are potent toxins with adverse impacts on human and marine animal health. To identify polyketide synthase (PKS) genes in the brevetoxin-producing dinoflagellate, Karenia brevis, we assembled a transcriptome from 595 million Illumina reads, sampled under different growth conditions. The assembly included 125,687 transcripts greater than 300 nt in length, with over half having >100× coverage. We found 121 transcripts encoding Type I ketosynthase (KS) domains, of which 99 encoded single KS domains, while 22 contained multiple KS domains arranged in 1-3 protein modules. Phylogenetic analysis placed all single domain and a majority of multidomain KSs within a monophyletic clade of protist PKSs. In contrast with the highly amplified single-domain KSs, only eight single-domain ketoreductase transcripts were found in the assembly, suggesting that they are more evolutionarily conserved. The multidomain PKSs were dominated by trans-acyltransferase architectures, which were recently shown to be prevalent in other algal protists. Karenia brevis also expressed several hybrid nonribosomal peptide synthetase (NRPS)/PKS sequences, including a burA-like sequence previously reported in a wide variety of dinoflagellates. This contrasts with a similarly deep transcriptome of Gambierdiscus polynesiensis, which lacked NRPS/PKS other than the burA-like transcript, and may reflect the presence of amide-containing polyketides in K. brevis and their absence from G. polynesiensis. In concert with other recent transcriptome analyses, this study provides evidence for both single domain and multidomain PKSs in the synthesis of polyketide compounds in dinoflagellates.
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Affiliation(s)
- Frances M. Van Dolah
- College of CharlestonSchool of Sciences and Mathematics66 George St.CharlestonSouth Carolina29424USA
- Hollings Marine Laboratory331 Fort Johnson Rd.CharlestonSouth Carolina29412USA
| | - Gurjeet S. Kohli
- Climate Change ClusterUniversity of Technology Sydney15 Broadway, UltimoSydneyNew South Wales2007Australia
- Singapore Centre for Environmental Life Sciences EngineeringNanyang Technological UniversitySingapore689528
| | - Jeanine S. Morey
- Hollings Marine Laboratory331 Fort Johnson Rd.CharlestonSouth Carolina29412USA
- JHT Incorporated2710 Discovery Dr.OrlandoFlorida32826USA
| | - Shauna A. Murray
- Climate Change ClusterUniversity of Technology Sydney15 Broadway, UltimoSydneyNew South Wales2007Australia
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14
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Sakai T, Fukuta A, Nakamura K, Nakano M, Mori Y. Total Synthesis of Brevisamide Using an Oxiranyl Anion Strategy. J Org Chem 2016; 81:3799-808. [PMID: 27057586 DOI: 10.1021/acs.joc.6b00484] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A total synthesis of brevisamide, a marine monocyclic ether amide isolated from the dinoflagellate Karenia brevis, has been achieved in 18 steps starting from 4-(benzyloxy)butanol. The synthesis involves oxiranyl anion coupling between an epoxy sulfone and a triflate, intramolecular etherification of a hydroxy-bromoketone, diastereoselective introduction of the axial methyl group by hydroxyl-directed hydrogenation of an exocyclic olefin, and installation of an acetamide side chain by nucleophilic substitution of an N-acetyl carbamate. The dienal side chain is assembled using a Horner-Wadsworth-Emmons reaction to complete the synthesis.
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Affiliation(s)
- Takeo Sakai
- Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Ayumi Fukuta
- Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Kumiko Nakamura
- Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Masato Nakano
- Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Yuji Mori
- Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
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15
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Friesen JB, McAlpine JB, Chen SN, Pauli GF. Countercurrent Separation of Natural Products: An Update. JOURNAL OF NATURAL PRODUCTS 2015; 78:1765-96. [PMID: 26177360 PMCID: PMC4517501 DOI: 10.1021/np501065h] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Indexed: 05/02/2023]
Abstract
This work assesses the current instrumentation, method development, and applications in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CCS). The article provides a critical review of the CCS literature from 2007 since our last review (J. Nat. Prod. 2008, 71, 1489-1508), with a special emphasis on the applications of CCS in natural products research. The current state of CCS is reviewed in regard to three continuing topics (instrumentation, solvent system development, theory) and three new topics (optimization of parameters, workflow, bioactivity applications). The goals of this review are to deliver the necessary background with references for an up-to-date perspective of CCS, to point out its potential for the natural product scientist, and thereby to induce new applications in natural product chemistry, metabolome, and drug discovery research involving organisms from terrestrial and marine sources.
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Affiliation(s)
- J. Brent Friesen
- Department
of Medicinal Chemistry and Pharmacognosy and Institute for Tuberculosis Research,
College of Pharmacy, University of Illinois
at Chicago, Chicago, Illinois 60612, United
States
- Physical
Sciences Department, Rosary College of Arts and Sciences, Dominican University, River Forest, Illinois 60305, United States
| | - James B. McAlpine
- Department
of Medicinal Chemistry and Pharmacognosy and Institute for Tuberculosis Research,
College of Pharmacy, University of Illinois
at Chicago, Chicago, Illinois 60612, United
States
| | - Shao-Nong Chen
- Department
of Medicinal Chemistry and Pharmacognosy and Institute for Tuberculosis Research,
College of Pharmacy, University of Illinois
at Chicago, Chicago, Illinois 60612, United
States
| | - Guido F. Pauli
- Department
of Medicinal Chemistry and Pharmacognosy and Institute for Tuberculosis Research,
College of Pharmacy, University of Illinois
at Chicago, Chicago, Illinois 60612, United
States
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16
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Fowler N, Tomas C, Baden D, Campbell L, Bourdelais A. Chemical analysis of Karenia papilionacea. Toxicon 2015; 101:85-91. [PMID: 25981346 DOI: 10.1016/j.toxicon.2015.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 11/16/2022]
Abstract
One of the most widely studied organisms responsible for Harmful Algal Blooms (HABs) is the marine dinoflagellate Karenia brevis. This organism produces neurotoxic compounds known as brevetoxins. A related dinoflagellate, Karenia papilionacea, has been reported to occasionally co-bloom with K. brevis but has received little attention as a possible toxin producing species. Therefore, our aim was to investigate the toxin profile for K. papilionacea. A toxic fraction was identified using a cell based cytotoxicity assay and the toxin was isolated and identified as the ladder frame polyether brevetoxin-2 (PbTx-2) using mass spectrometry (MS) and nuclear magnetic resonance (NMR). Toxin production in K. papilionacea increased in response to hypoosmotic stress, as previously observed in K. brevis.
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Affiliation(s)
- Nicholas Fowler
- University of North Carolina, Center of Marine Science, Wilmington, NC, 28409, USA.
| | - Carmelo Tomas
- University of North Carolina, Center of Marine Science, Wilmington, NC, 28409, USA.
| | - Daniel Baden
- University of North Carolina, Center of Marine Science, Wilmington, NC, 28409, USA.
| | - Lisa Campbell
- Texas A&M Univ, Dept Biol, College Stn, TX, 77843, USA.
| | - Andrea Bourdelais
- University of North Carolina, Center of Marine Science, Wilmington, NC, 28409, USA.
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17
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McCall JR, Goodman AJ, Jacocks HM, Thompson A, Baden DG, Bourdelais AJ. Development of a fluorescence assay for the characterization of brevenal binding to rat brain synaptosomes. JOURNAL OF NATURAL PRODUCTS 2014; 77:2014-20. [PMID: 25226846 PMCID: PMC4176390 DOI: 10.1021/np500118p] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Indexed: 06/03/2023]
Abstract
The marine dinoflagellate Karenia brevis produces a family of neurotoxins known as brevetoxins. Brevetoxins elicit their effects by binding to and activating voltage-sensitive sodium channels (VSSCs) in cell membranes. K. brevis also produces brevenal, a brevetoxin antagonist, which is able to inhibit and/or negate many of the detrimental effects of brevetoxins. Brevenal binding to VSSCs has yet to be fully characterized, in part due to the difficulty and expense of current techniques. In this study, we have developed a novel fluorescence binding assay for the brevenal binding site. Several fluorescent compounds were conjugated to brevenal to assess their effects on brevenal binding. The assay was validated against the radioligand assay for the brevenal binding site and yielded comparable equilibrium inhibition constants. The fluorescence-based assay was shown to be quicker and far less expensive and did not generate radioactive waste or need facilities for handling radioactive materials. In-depth studies using the brevenal conjugates showed that, while brevenal conjugates do bind to a binding site in the VSSC protein complex, they are not displaced by known VSSC site specific ligands. As such, brevenal elicits its action through a novel mechanism and/or currently unknown receptor site on VSSCs.
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Affiliation(s)
- Jennifer R. McCall
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Allan J. Goodman
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Henry M. Jacocks
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Alysha
M. Thompson
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Daniel G. Baden
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
| | - Andrea J. Bourdelais
- Center
for Marine Science, University of North
Carolina at Wilmington, Wilmington, North Carolina 28409, United States
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18
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McCall JR, Elliott EA, Bourdelais AJ. A new cytotoxicity assay for brevetoxins using fluorescence microscopy. Mar Drugs 2014; 12:4868-82. [PMID: 25251033 PMCID: PMC4178485 DOI: 10.3390/md12094868] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/01/2014] [Accepted: 09/04/2014] [Indexed: 11/16/2022] Open
Abstract
Brevetoxins are a family of ladder-framed polyether toxins produced during blooms of the marine dinoflagellate, Karenia brevis. Consumption of shellfish or finfish exposed to brevetoxins can lead to the development of neurotoxic shellfish poisoning. The toxic effects of brevetoxins are believed to be due to the activation of voltage-sensitive sodium channels in cell membranes. The traditional cytotoxicity assay for detection of brevetoxins uses the Neuro-2A cell line, which must first be treated with the neurotoxins, ouabain and veratridine, in order to become sensitive to brevetoxins. In this study, we demonstrate several drawbacks of the Neuro-2A assay, which include variability for the EC50 values for brevetoxin and non-linear triphasic dose response curves. Ouabain/veratridine-treated Neuro-2A cells do not show a typical sigmoidal dose response curve in response to brevetoxin, but rather, have a polynomial shaped curve, which makes calculating EC50 values highly variable. We describe a new fluorescence live cell imaging model, which allows for accurate calculation of cytotoxicity via nuclear staining and additional measurement of other viability parameters depending on which aspect of the cell is stained. In addition, the SJCRH30 cell line shows promise as an alternative to Neuro-2A cells for testing brevetoxins without the need for ouabain and veratridine.
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Affiliation(s)
- Jennifer R McCall
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
| | - Elizabeth A Elliott
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
| | - Andrea J Bourdelais
- UNCW Center for Marine Science, 5600 Marvin K Moss Lane, Wilmington, NC 28409, USA.
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19
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Calabro K, Guigonis JM, Teyssié JL, Oberhänsli F, Goudour JP, Warnau M, Bottein MYD, Thomas OP. Further insights into brevetoxin metabolism by de novo radiolabeling. Toxins (Basel) 2014; 6:1785-98. [PMID: 24918358 PMCID: PMC4073129 DOI: 10.3390/toxins6061785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Revised: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 11/16/2022] Open
Abstract
The toxic dinoflagellate Karenia brevis, responsible for early harmful algal blooms in the Gulf of Mexico, produces many secondary metabolites, including potent neurotoxins called brevetoxins (PbTx). These compounds have been identified as toxic agents for humans, and they are also responsible for the deaths of several marine organisms. The overall biosynthesis of these highly complex metabolites has not been fully ascertained, even if there is little doubt on a polyketide origin. In addition to gaining some insights into the metabolic events involved in the biosynthesis of these compounds, feeding studies with labeled precursors helps to discriminate between the de novo biosynthesis of toxins and conversion of stored intermediates into final toxic products in the response to environmental stresses. In this context, the use of radiolabeled precursors is well suited as it allows working with the highest sensitive techniques and consequently with a minor amount of cultured dinoflagellates. We were then able to incorporate [U-¹⁴C]-acetate, the renowned precursor of the polyketide pathway, in several PbTx produced by K. brevis. The specific activities of PbTx-1, -2, -3, and -7, identified by High-Resolution Electrospray Ionization Mass Spectrometer (HRESIMS), were assessed by HPLC-UV and highly sensitive Radio-TLC counting. We demonstrated that working at close to natural concentrations of acetate is a requirement for biosynthetic studies, highlighting the importance of highly sensitive radiolabeling feeding experiments. Quantification of the specific activity of the four, targeted toxins led us to propose that PbTx-1 and PbTx-2 aldehydes originate from oxidation of the primary alcohols of PbTx-7 and PbTx-3, respectively. This approach will open the way for a better comprehension of the metabolic pathways leading to PbTx but also to a better understanding of their regulation by environmental factors.
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Affiliation(s)
- Kevin Calabro
- Institut de Chimie de Nice-PCRE (Processus Chimiques et Radiochimiques dans l'Environnement), UMR 7272 CNRS, Université de Nice Sophia-Antipolis, Faculté des Sciences, Parc Valrose Nice 06108, France.
| | - Jean-Marie Guigonis
- Plateforme "Bernard Rossi"-Laboratoire TIRO (Transporteur en Imagerie Radiothérapie et Oncologie), UMR E 4320 CEA /iBEB /SBTN-CAL, Université de Nice Sophia Antipolis, Faculté de Médecine, 28 Avenue de Valombrose, Nice 06107, France.
| | - Jean-Louis Teyssié
- Radioecology Laboratory, International Atomic Energy Agency-Environment Laboratories, MC 98012, Monaco.
| | - François Oberhänsli
- Radioecology Laboratory, International Atomic Energy Agency-Environment Laboratories, MC 98012, Monaco.
| | - Jean-Pierre Goudour
- Geoazur Laboratory, Université de Nice-Sophia-Antipolis, UMR 7329 CNRS, UR 082 IRD, Campus Azur CNRS Bât. 1, 250 rue Albert Einstein, Sophia Antipolis Valbonne 06560, France.
| | - Michel Warnau
- Radioecology Laboratory, International Atomic Energy Agency-Environment Laboratories, MC 98012, Monaco.
| | | | - Olivier P Thomas
- Institut de Chimie de Nice-PCRE (Processus Chimiques et Radiochimiques dans l'Environnement), UMR 7272 CNRS, Université de Nice Sophia-Antipolis, Faculté des Sciences, Parc Valrose Nice 06108, France.
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20
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Satake M, Shirai T, Takimoto Y, Kuranaga T, Tachibana K, G. Baden D, L. C. Wright J. Synthesis and Cyclization of a Proposed Biosynthetic Epoxy Intermediate of a Marine Monocyclic Ether Amide, Brevisamide. HETEROCYCLES 2014. [DOI: 10.3987/com-13-12880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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21
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Van Dolah FM, Zippay ML, Pezzolesi L, Rein KS, Johnson JG, Morey JS, Wang Z, Pistocchi R. Subcellular localization of dinoflagellate polyketide synthases and fatty acid synthase activity. JOURNAL OF PHYCOLOGY 2013; 49:1118-1127. [PMID: 27007632 DOI: 10.1111/jpy.12120] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/25/2013] [Indexed: 06/05/2023]
Abstract
Dinoflagellates are prolific producers of polyketide secondary metabolites. Dinoflagellate polyketide synthases (PKSs) have sequence similarity to Type I PKSs, megasynthases that encode all catalytic domains on a single polypeptide. However, in dinoflagellate PKSs identified to date, each catalytic domain resides on a separate transcript, suggesting multiprotein complexes similar to Type II PKSs. Here, we provide evidence through coimmunoprecipitation that single-domain ketosynthase and ketoreductase proteins interact, suggesting a predicted multiprotein complex. In Karenia brevis (C.C. Davis) Gert Hansen & Ø. Moestrup, previously observed chloroplast localization of PKSs suggested that brevetoxin biosynthesis may take place in the chloroplast. Here, we report that PKSs are present in both cytosol and chloroplast. Furthermore, brevetoxin is not present in isolated chloroplasts, raising the question of what chloroplast-localized PKS enzymes might be doing. Antibodies to K. brevis PKSs recognize cytosolic and chloroplast proteins in Ostreopsis cf. ovata Fukuyo, and Coolia monotis Meunier, which produce different suites of polyketide toxins, suggesting that these PKSs may share common pathways. Since PKSs are closely related to fatty acid synthases (FAS), we sought to determine if fatty acid biosynthesis colocalizes with either chloroplast or cytosolic PKSs. [(3) H]acetate labeling showed fatty acids are synthesized in the cytosol, with little incorporation in chloroplasts, consistent with a Type I FAS system. However, although 29 sequences in a K. brevis expressed sequence tag database have similarity (BLASTx e-value <10(-10) ) to PKSs, no transcripts for either Type I (cytosolic) or Type II (chloroplast) FAS are present. Further characterization of the FAS complexes may help to elucidate the functions of the PKS enzymes identified in dinoflagellates.
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Affiliation(s)
- Frances M Van Dolah
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
- Marine Biomedical and Environmental Sciences, Medical University of South Carolina, Charleston, South Carolina, 29412, USA
| | - Mackenzie L Zippay
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
- Marine Biomedical and Environmental Sciences, Medical University of South Carolina, Charleston, South Carolina, 29412, USA
| | - Laura Pezzolesi
- Interdepartmental Research Centre for Environmental Science (CIRSA), University of Bologna, Ravenna, 48123, Italy
| | - Kathleen S Rein
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
| | - Jillian G Johnson
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
- Marine Biomedical and Environmental Sciences, Medical University of South Carolina, Charleston, South Carolina, 29412, USA
| | - Jeanine S Morey
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
| | - Zhihong Wang
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
| | - Rossella Pistocchi
- Interdepartmental Research Centre for Environmental Science (CIRSA), University of Bologna, Ravenna, 48123, Italy
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22
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Mayer AMS, Rodríguez AD, Taglialatela-Scafati O, Fusetani N. Marine pharmacology in 2009-2011: marine compounds with antibacterial, antidiabetic, antifungal, anti-inflammatory, antiprotozoal, antituberculosis, and antiviral activities; affecting the immune and nervous systems, and other miscellaneous mechanisms of action. Mar Drugs 2013; 11:2510-73. [PMID: 23880931 PMCID: PMC3736438 DOI: 10.3390/md11072510] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/04/2013] [Accepted: 06/14/2013] [Indexed: 12/13/2022] Open
Abstract
The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.
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Affiliation(s)
- Alejandro M. S. Mayer
- Department of Pharmacology, Chicago College of Osteopathic Medicine, Midwestern University, 555 31st Street, Downers Grove, Illinois 60515, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-630-515-6951; Fax: +1-630-971-6414
| | - Abimael D. Rodríguez
- Department of Chemistry, University of Puerto Rico, San Juan, Puerto Rico 00931, USA; E-Mail:
| | - Orazio Taglialatela-Scafati
- Department of Pharmacy, University of Naples “Federico II”, Via D. Montesano 49, I-80131 Napoli, Italy; E-Mail:
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23
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Gold EP, Jacocks HM, Bourdelais AJ, Baden DG. Brevenal, a brevetoxin antagonist from Karenia brevis, binds to a previously unreported site on mammalian sodium channels. HARMFUL ALGAE 2013; 26:12-19. [PMID: 23789024 PMCID: PMC3684244 DOI: 10.1016/j.hal.2013.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Brevetoxins are a family of ladder-frame polyether toxins produced by the marine dinoflagellate Karenia brevis. During blooms of K. brevis, inhalation of brevetoxins aerosolized by wind and wave action can lead to asthma-like symptoms in persons at the beach. Consumption of either shellfish or finfish contaminated by K. brevis blooms can lead to the development of neurotoxic shellfish poisoning. The toxic effects of brevetoxins are due to binding at a defined site on, and subsequent activation of, voltage-sensitive sodium channels (VSSCs) in cell membranes (site 5). In addition to brevetoxins, K. brevis produces several other ladder-frame compounds. One of these compounds, brevenal, has been shown to antagonize the effects of brevetoxin. In an effort to further characterize to effects of brevenal, a radioactive analog ([3H]-brevenol) was produced by reducing the side-chain terminal aldehyde moiety of brevenal to an alcohol using tritiated sodium borohydride. A KD of 67 nM and Bmax of 7.1 pmol/mg protein were obtained for [3H]-brevenol in rat brain synaptosomes, suggesting a 1:1 matching with VSSCs. Brevenal and brevenol competed for [3H]-brevenol binding with Ki values of 75 nM and 56 nM, respectively. However, although both brevenal and brevenol can inhibit brevetoxin binding, brevetoxin was completely ineffective at competition for [3H]-brevenol binding. After examining other site-specific compounds, it was determined that [3H]-brevenol binds to a site that is distinct from the other known sites including the brevetoxin site (site 5) although some interaction with site 5 is apparent.
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Affiliation(s)
- Elena P. Gold
- Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409
| | - Henry M. Jacocks
- Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409
| | - Andrea J. Bourdelais
- Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409
| | - Daniel G. Baden
- Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409
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24
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McCall JR, Jacocks HM, Baden DG, Bourdelais AJ. Development of a competitive fluorescence-based synaptosome binding assay for brevetoxins. HARMFUL ALGAE 2012; 19:85-91. [PMID: 22984362 PMCID: PMC3440185 DOI: 10.1016/j.hal.2012.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Brevetoxins are a family of ladder-frame polyether toxins produced during blooms of the marine dinoflagellate Karenia brevis. Inhalation of brevetoxins aerosolized by wind and wave action can lead to asthma-like symptoms in beach goers. Consumption of either shellfish or finfish exposed to K. brevis blooms can lead to the development of neurotoxic shellfish poisoning. The toxic effects of brevetoxins are due to activation of voltage-sensitive sodium channels (VSSCs) in cell membranes. Binding of brevetoxin analogs and competitors to site 5 on these channels has historically been measured using a radioligand competition assay that is fraught with difficulty, including slow analysis time, production of radioactive waste, and cumbersome and expensive methods associated with the generation of radioactive labeled ligands. In this study, we describe the development of a novel fluorescent synaptosome binding assay for the brevetoxin receptor. BODIPY(®)-conjugated to PbTx-2 was used as the labeled ligand. The BODIPY(®)-PbTx-2 conjugate was found to displace [(3)H]-PbTx-3 from its binding site on VSSCs on rat brain synaptosomes with an equilibrium inhibition constant of 0.11 nM. We have shown that brevetoxin A and B analogs are all able to compete for binding with the fluorescent ligand. Most importantly, this assay was validated against the current site 5 receptor binding assay standard, the radioligand receptor assay for the brevetoxin receptor using [(3)H]-PbTx-3 as the labeled ligand. The fluorescence based assay yielded equilibrium inhibition constants comparable to the radioligand assay for all brevetoxin analogs. The fluorescence based assay was quicker, far less expensive, and did not generate radioactive waste or need radioactive facilities. As such, this fluorescence-based assay can be used to replace the current radioligand assay for site 5 on voltage-sensitive sodium channels and will be a vital tool for future experiments examining the binding affinity of various ligands for site 5 on sodium channels.
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Affiliation(s)
- Jennifer R. McCall
- Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409
- Corresponding Author, Tel: 910-962-2081, FAX: 910-962-2410,
| | - Henry M. Jacocks
- Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409
| | - Daniel G. Baden
- Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409
| | - Andrea J. Bourdelais
- Center for Marine Science, University of North Carolina at Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409
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25
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Abstract
Covering: 2010. Previous review: Nat. Prod. Rep., 2011, 28, 196. This review covers the literature published in 2010 for marine natural products, with 895 citations (590 for the period January to December 2010) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1003 for 2010), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.
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Affiliation(s)
- John W Blunt
- Department of Chemistry, University of Canterbury, Christchurch, New Zealand.
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26
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Redshaw CH, Sutter D, Myers TL, Naar J, Kubanek J. Tracking losses of brevetoxins on exposure to phytoplankton competitors: Mechanistic insights. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 100:365-372. [PMID: 20863581 DOI: 10.1016/j.aquatox.2010.08.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Revised: 08/24/2010] [Accepted: 08/26/2010] [Indexed: 05/29/2023]
Abstract
The increasing frequency of devastating blooms of the harmful dinoflagellate Karenia brevis has motivated investigations into understanding bloom dynamics and the potential for mitigation. Previous findings indicate that waterborne concentrations of the most abundant brevetoxin (brevetoxin B or PbTx-2) associated with these blooms decrease in the presence of other phytoplankton species. The current study explores the mechanism of brevetoxin removal from seawater upon exposure to phytoplankton competitors. Live phytoplankton removed waterborne brevetoxins more rapidly than lysates, but phytoplankton did not need to be in a state of active metabolism. Biomolecules, probably proteins, exuded from phytoplankton appeared to be responsible for the loss of brevetoxins, either by irreversible complexation or by degradation. Selective removal of PbTx-2 and -1, but not PbTx-3, -9 or BTX-B5, by cultured phytoplankton revealed that brevetoxin removal is dependent upon the presence of an α,β-unsaturated aldehyde functionality. The mechanism of biotransformation appears to be common among phytoplankton, since members of various taxonomic groups including diatoms, dinoflagellates, and a cryptophyte each caused 75-90% decrease in PbTx-2 concentration, as did a generic protein (bovine serum albumin) added to seawater at high concentration. These findings support the concept of potentially using competitor phytoplankton species or compounds derived from phytoplankton as biocontrol agents for waterborne toxins associated with red tide.
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