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Brown MO, Olagunju BO, Giner JL, Welander PV. Sterol methyltransferases in uncultured bacteria complicate eukaryotic biomarker interpretations. Nat Commun 2023; 14:1859. [PMID: 37012227 PMCID: PMC10070321 DOI: 10.1038/s41467-023-37552-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 03/22/2023] [Indexed: 04/05/2023] Open
Abstract
Sterane molecular fossils are broadly interpreted as eukaryotic biomarkers, although diverse bacteria also produce sterols. Steranes with side-chain methylations can act as more specific biomarkers if their sterol precursors are limited to particular eukaryotes and are absent in bacteria. One such sterane, 24-isopropylcholestane, has been attributed to demosponges and potentially represents the earliest evidence for animals on Earth, but enzymes that methylate sterols to give the 24-isopropyl side-chain remain undiscovered. Here, we show that sterol methyltransferases from both sponges and yet-uncultured bacteria function in vitro and identify three methyltransferases from symbiotic bacteria each capable of sequential methylations resulting in the 24-isopropyl sterol side-chain. We demonstrate that bacteria have the genomic capacity to synthesize side-chain alkylated sterols, and that bacterial symbionts may contribute to 24-isopropyl sterol biosynthesis in demosponges. Together, our results suggest bacteria should not be dismissed as potential contributing sources of side-chain alkylated sterane biomarkers in the rock record.
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Affiliation(s)
- Malory O Brown
- Department of Earth System Science, Stanford University, Stanford, CA, 94305, USA
| | - Babatunde O Olagunju
- Department of Chemistry, State University of New York-Environmental Science and Forestry, Syracuse, NY, 13210, USA
| | - José-Luis Giner
- Department of Chemistry, State University of New York-Environmental Science and Forestry, Syracuse, NY, 13210, USA
| | - Paula V Welander
- Department of Earth System Science, Stanford University, Stanford, CA, 94305, USA.
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Dagorn F, Couzinet-Mossion A, Kendel M, Beninger PG, Rabesaotra V, Barnathan G, Wielgosz-Collin G. Exploitable Lipids and Fatty Acids in the Invasive Oyster Crassostrea gigas on the French Atlantic Coast. Mar Drugs 2016; 14:md14060104. [PMID: 27231919 PMCID: PMC4926063 DOI: 10.3390/md14060104] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 12/16/2022] Open
Abstract
Economic exploitation is one means to offset the cost of controlling invasive species, such as the introduced Pacific oyster (Crassostrea gigas Thunberg) on the French Atlantic coast. Total lipid and phospholipid (PL) fatty acids (FAs) and sterols were examined in an invasive population of C. gigas in Bourgneuf Bay, France, over four successive seasons, with a view to identify possible sources of exploitable substances. The total lipid level (% dry weight) varied from 7.1% (winter) to 8.6% (spring). Of this, PLs accounted for 28.1% (spring) to 50.4% (winter). Phosphatidylcholine was the dominant PL throughout the year (up to 74% of total PLs in winter). Plasmalogens were identified throughout the year as a series of eleven dimethylacetals (DMAs) with chain lengths between C16 and C20 (up to 14.5% of PL FAs + DMAs in winter). Thirty-seven FAs were identified in the PL FAs. Eicosapentaenoic acid (20:5n-3 EPA/7.53% to 14.5%) and docosahexaenoic acid (22:6n-3 DHA/5.51% to 9.5%) were the dominant polyunsaturated FAs in all seasons. Two non-methylene-interrupted dienoic (NMID) FAs were identified in all seasons: 7,13-docosadienoic and 7,15-docosadienoic acids, the latter being present at relatively high levels (up to 9.6% in winter). Twenty free sterols were identified, including cholesterol at 29.9% of the sterol mixture and about 33% of phytosterols. C. gigas tissues thus contained exploitable lipids for health benefits or as a potential source of high-quality commercial lecithin.
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Affiliation(s)
- Flore Dagorn
- Faculté des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR3473 CNRS, 9 rue Bias, BP 53508, F-44035 Nantes Cedex 1, France.
| | - Aurélie Couzinet-Mossion
- Faculté des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR3473 CNRS, 9 rue Bias, BP 53508, F-44035 Nantes Cedex 1, France.
| | - Melha Kendel
- Faculté des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR3473 CNRS, 9 rue Bias, BP 53508, F-44035 Nantes Cedex 1, France.
| | - Peter G Beninger
- Faculté des Sciences et des Techniques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR34473 CNRS, 2 rue de La Houssinière BP 92208, F-44322 Nantes Cedex 3, France.
| | - Vony Rabesaotra
- Faculté des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR3473 CNRS, 9 rue Bias, BP 53508, F-44035 Nantes Cedex 1, France.
| | - Gilles Barnathan
- Faculté des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR3473 CNRS, 9 rue Bias, BP 53508, F-44035 Nantes Cedex 1, France.
| | - Gaëtane Wielgosz-Collin
- Faculté des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR3473 CNRS, 9 rue Bias, BP 53508, F-44035 Nantes Cedex 1, France.
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Multiple beneficial lipids including lecithin detected in the edible invasive mollusk Crepidula fornicata from the French Northeastern Atlantic coast. Mar Drugs 2014; 12:6254-68. [PMID: 25532566 PMCID: PMC4278228 DOI: 10.3390/md12126254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/08/2014] [Accepted: 12/10/2014] [Indexed: 12/14/2022] Open
Abstract
The invasive mollusk Crepidula fornicata, occurring in large amounts in bays along the French Northeastern Atlantic coasts, may have huge environmental effects in highly productive ecosystems where shellfish are exploited. The present study aims at determining the potential economic value of this marine species in terms of exploitable substances with high added value. Lipid content and phospholipid (PL) composition of this mollusk collected on the Bourgneuf Bay were studied through four seasons. Winter specimens contained the highest lipid levels (5.3% dry weight), including 69% of PLs. Phosphatidylcholine (PC) was the major PL class all year, accounting for 63.9% to 88.9% of total PLs. Consequently, the winter specimens were then investigated for PL fatty acids (FAs), and free sterols. Dimethylacetals (DMAs) were present (10.7% of PL FA + DMA mixture) revealing the occurrence of plasmalogens. More than forty FAs were identified, including 20:5n-3 (9.4%) and 22:6n-3 (7.3%) acids. Fourteen free sterols were present, including cholesterol at 31.3% of the sterol mixture and about 40% of phytosterols. These data on lipids of C. fornicata demonstrate their positive attributes for human nutrition and health. The PL mixture, rich in PC and polyunsaturated FAs, offers an interesting alternative source of high value-added marine lecithin.
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