Novel Sulfonolipid in the Extremely Halophilic Bacterium <i>Salinibacter ruber</i>
Bibliographic record
Abstract
Salinibacter ruber is an extremely halophilic bacterium, phylogenetically affiliated with the Flavobacterium/Cytophaga branch of the domain Bacteria. Electrospray mass analyses (negative ion) of the total lipid extract of a pure culture of S. ruber shows a characteristic peak at m/z 660 as the most prominent peak in the high-mass range of the spectrum. A novel sulfonolipid, giving rise to the molecular ion [M-H]- of m/z 660, has been identified. The sulfonolipid isolated and purified by thin-layer chromatography was shown by chemical degradation, mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance analysis to have the structure 2-carboxy-2-amino-3-O-(13'-methyltetradecanoyl)-4-hydroxy-18-methylnonadec-5-ene-1-sulfonic acid. This lipid represents about 10% of total cellular lipids, and it appears to be a structural variant of the sulfonolipids found as main components of the cell envelope of gliding bacteria of the genus Cytophaga and closely related genera (W. Godchaux and E. R. Leadbetter, J. Bacteriol. 153:1238-1246, 1983) and of diatoms (R. Anderson, M. Kates, and B. E. Volcani, Biochim. Biophys. Acta 528:89-106, 1978). Since this sulfonolipid has never been observed in any other extreme halophilic microorganism, we consider the peak at m/z 660 the lipid signature of Salinibacter. This study suggests that this novel sulfonolipid may be used as a chemotaxonomic marker for the detection of Salinibacter within the halophilic microbial community in saltern crystallizer ponds and other hypersaline environments.
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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".