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Haq S, Oyler BL, Williams E, Khan MM, Goodlett DR, Bachvaroff T, Place AR. Investigating A Multi-Domain Polyketide Synthase in Amphidinium carterae. Mar Drugs 2023; 21:425. [PMID: 37623706 PMCID: PMC10455422 DOI: 10.3390/md21080425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/14/2023] [Accepted: 07/25/2023] [Indexed: 08/26/2023] Open
Abstract
Dinoflagellates are unicellular organisms that are implicated in harmful algal blooms (HABs) caused by potent toxins that are produced through polyketide synthase (PKS) pathways. However, the exact mechanisms of toxin synthesis are unknown due to a lack of genomic segregation of fat, toxins, and other PKS-based pathways. To better understand the underlying mechanisms, the actions and expression of the PKS proteins were investigated using the toxic dinoflagellate Amphidinium carterae as a model. Cerulenin, a known ketosynthase inhibitor, was shown to reduce acetate incorporation into all fat classes with the toxins amphidinol and sulpho-amphidinol. The mass spectrometry analysis of cerulenin-reacted synthetic peptides derived from ketosynthase domains of A. carterae multimodular PKS transcripts demonstrated a strong covalent bond that could be localized using collision-induced dissociation. One multi-modular PKS sequence present in all dinoflagellates surveyed to date was found to lack an AT domain in toxin-producing species, indicating trans-acting domains, and was shown by Western blotting to be post-transcriptionally processed. These results demonstrate how toxin synthesis in dinoflagellates can be differentiated from fat synthesis despite common underlying pathway.
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Affiliation(s)
- Saddef Haq
- Institute for Marine and Environmental Technologies, University of Maryland Center for Environmental Science, 701 East Pratt St., Baltimore, MD 21202, USA; (S.H.); (E.W.); (T.B.)
| | - Benjamin L. Oyler
- University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, USA; (B.L.O.); (M.M.K.)
| | - Ernest Williams
- Institute for Marine and Environmental Technologies, University of Maryland Center for Environmental Science, 701 East Pratt St., Baltimore, MD 21202, USA; (S.H.); (E.W.); (T.B.)
| | - Mohd M. Khan
- University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, USA; (B.L.O.); (M.M.K.)
| | - David R. Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8S 1P7, Canada;
| | - Tsvetan Bachvaroff
- Institute for Marine and Environmental Technologies, University of Maryland Center for Environmental Science, 701 East Pratt St., Baltimore, MD 21202, USA; (S.H.); (E.W.); (T.B.)
| | - Allen R. Place
- Institute for Marine and Environmental Technologies, University of Maryland Center for Environmental Science, 701 East Pratt St., Baltimore, MD 21202, USA; (S.H.); (E.W.); (T.B.)
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Marzonie M, Flores F, Sadoun N, Thomas MC, Valada-Mennuni A, Kaserzon S, Mueller JF, Negri AP. Toxicity thresholds of nine herbicides to coral symbionts (Symbiodiniaceae). Sci Rep 2021; 11:21636. [PMID: 34737333 PMCID: PMC8568975 DOI: 10.1038/s41598-021-00921-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/14/2021] [Indexed: 01/22/2023] Open
Abstract
Over 30 herbicides have been detected in catchments and waters of the Great Barrier Reef (GBR) and their toxicity to key tropical species, including the coral endosymbiotic algae Symbiodiniaceae, is not generally considered in current water quality guideline values (WQGVs). Mutualistic symbionts of the family Symbiodiniaceae are essential for the survival of scleractinian corals. We tested the effects of nine GBR-relevant herbicides on photosynthetic efficiency (ΔF/Fm′) and specific growth rate (SGR) over 14 days of cultured coral endosymbiont Cladocopium goreaui (formerly Symbiodinium clade C1). All seven Photosystem II (PSII) herbicides tested inhibited ΔF/Fm′ and SGR, with toxicity thresholds for SGR ranging between 2.75 and 320 µg L−1 (no effect concentration) and 2.54–257 µg L−1 (EC10). There was a strong correlation between EC50s for ΔF/Fm′ and SGR for all PSII herbicides indicating that inhibition of ΔF/Fm′ can be considered a biologically relevant toxicity endpoint for PSII herbicides to this species. The non-PSII herbicides haloxyfop and imazapic did not affect ΔF/Fm′ or SGR at the highest concentrations tested. The inclusion of this toxicity data for Symbiodiniaceae will contribute to improving WQGVs to adequately inform risk assessments and the management of herbicides in tropical marine ecosystems.
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Affiliation(s)
- Magena Marzonie
- Australian Institute of Marine Science, PMB No. 3, Townsville, QLD, 4810, Australia.,AIMS@JCU: Australian Institute of Marine Science and College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia
| | - Florita Flores
- Australian Institute of Marine Science, PMB No. 3, Townsville, QLD, 4810, Australia. .,AIMS@JCU: Australian Institute of Marine Science and College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia.
| | - Nora Sadoun
- Australian Institute of Marine Science, PMB No. 3, Townsville, QLD, 4810, Australia
| | - Marie C Thomas
- Australian Institute of Marine Science, PMB No. 3, Townsville, QLD, 4810, Australia
| | - Anais Valada-Mennuni
- Australian Institute of Marine Science, PMB No. 3, Townsville, QLD, 4810, Australia
| | - Sarit Kaserzon
- Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - Jochen F Mueller
- Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - Andrew P Negri
- Australian Institute of Marine Science, PMB No. 3, Townsville, QLD, 4810, Australia.,AIMS@JCU: Australian Institute of Marine Science and College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia
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Li-Beisson Y, Thelen JJ, Fedosejevs E, Harwood JL. The lipid biochemistry of eukaryotic algae. Prog Lipid Res 2019; 74:31-68. [PMID: 30703388 DOI: 10.1016/j.plipres.2019.01.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 02/06/2023]
Abstract
Algal lipid metabolism fascinates both scientists and entrepreneurs due to the large diversity of fatty acyl structures that algae produce. Algae have therefore long been studied as sources of genes for novel fatty acids; and, due to their superior biomass productivity, algae are also considered a potential feedstock for biofuels. However, a major issue in a commercially viable "algal oil-to-biofuel" industry is the high production cost, because most algal species only produce large amounts of oils after being exposed to stress conditions. Recent studies have therefore focused on the identification of factors involved in TAG metabolism, on the subcellular organization of lipid pathways, and on interactions between organelles. This has been accompanied by the development of genetic/genomic and synthetic biological tools not only for the reference green alga Chlamydomonas reinhardtii but also for Nannochloropsis spp. and Phaeodactylum tricornutum. Advances in our understanding of enzymes and regulatory proteins of acyl lipid biosynthesis and turnover are described herein with a focus on carbon and energetic aspects. We also summarize how changes in environmental factors can impact lipid metabolism and describe present and potential industrial uses of algal lipids.
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Affiliation(s)
- Yonghua Li-Beisson
- Aix-Marseille Univ, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F-13108, France.
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - Eric Fedosejevs
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.
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