Molecular species composition of polar lipids from two microalgae Nitzschia palea and Scenedesmus costatus using HPLC-ESI-MS/MS
Bibliographic record
Abstract
This work reports the polar lipid profiles of two freshwater algae: the diatom Nitzschia palea, widespread alga that typically inhabits freshwater ponds and rivers, and the Scenedesmus costatus, a common green alga. HILIC-ESI-MS/MS analysis was used to determine and quantify the major phospholipids and glycolipids, and their relative molecular species, extracted from the two microalgal cultures. Glycolipids were eluted first, followed by phospholipids partially co-eluting with the sulfoglycolipids. We also studied the fragmentation pattern in the negative ionization mode for galactolipids. The most intense daughter ion corresponded to the fatty acyl chain located at the sn-2 position, which allowed us to determine the stereospecific distribution of the following fatty acids on the glycerol backbone. For green algae, 18:3 fatty acid was frequently occurring in both phospholipids and galactolipids. We also found 16:4 in some molecular species of mono- and digalactosyldiacylglycerol (MGDG and DGDG). The most abundant and characteristic molecular species of MGDG in green algae exhibited the combination (18:3/16:4), whereas DGDG was more saturated than MGDG and contained mainly 18:1, 18:2, or 18:3 at sn-1 and shorter fragments 16:0, 16:1, 16:2, and 16:3 at sn-2. It is also remarkable that in the diatom, the phospholipids contained mainly molecular species with saturated or monounsaturated fatty acids such as 16:0, 16:1 and 18:1. In contrast, MGDG and DGDG contained a higher proportion of polyunsaturated fatty acids, such as the unique and abundant MGDG (20:5/20:2).
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| 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 teacher head, 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".