Incorporation of omega-3 polyunsaturated fatty acids into glycerolipids in microalga <i>Emiliania huxleyi</i> : radiochemical analysis of glycerolipid biosynthesis
Bibliographic record
Abstract
ABSTRACT Marine microalgae are primary producers of nutritionally important ω-3 polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA, 22:6n-3), and octadecapentaenoic acid (OPA, 18:5n-3). However, how these fatty acids, after synthesis, are incorporated into glycerolipids in microalgae remains largely unknown. To investigate the assembly of fatty acids and glycerol into different glycerolipids, 14 C-acetate and 14 C-glycerol were used to trace their flux into glycolipids (GL) and phospholipids (PL) in the microalga Emiliania huxleyi . 14 C-acetate labeling showed that freshly synthesized fatty acids were predominantly incorporated into phosphatidylethanolamine (PE) and phosphatidylcholine (PC) over monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), with the more efficient incorporation into the sn-2 position of PL. A similar flux pattern of glycerol backbone to glycerolipids was also observed in 14 C-glycerol labeling. Simultaneous decrease of both acyl and backbone fluxes to PE alongside the corresponding increase in PC over the labeling courses revealed the conversion of PE to PC through head group methylation. Positional analysis of labeled glycerolipids showed that saturated fatty acids (SFA) were initially found exclusively at the sn-2 position of MGDG, while OPA, not DHA, emerged in MGDG with preference at the sn-1 position. In contrast, DHA, not OPA, was incorporated into PC with preference at the sn-2 position. These results indicate that the two ω-3 fatty acids are incorporated through completely separate pathways in E. huxleyi . The knowledge about the biosynthesis and assembly of ω-3 PUFAs at the stereospecific positions of glycerolipids is highly valuable for developing targeted strategies in the metabolic engineering of these fatty acids in microalgae. IMPORTANCE Marine microalgae are primary producers of nutritionally important ω-3 long-chain polyunsaturated fatty acids (PUFAs). However, how these fatty acids, after synthesis, are incorporated into glycerolipids in microalgae remains largely unknown. To investigate the assembly of fatty acids and glycerol into different glycerolipids, 14 C-acetate and 14 C-glycerol were used to trace their flux into glycolipids and phospholipids with two different protocols, steady-state labeling and pulse-chase labeling in Emiliania huxleyi, a cosmopolitan microalga that can produce a high level of docosahexaenoic acid (DHA, 22:6n-3) and octadecapentaenoic acid (OPA, 18:5n-3). Results indicate that the two ω-3 fatty acids are incorporated through completely separate pathways with high stereospecificity in E. huxleyi . Knowledge gained from the research is highly valuable for developing targeted strategies for the optimized production and metabolic engineering of these fatty acids in microalgae and heterologous systems.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".