Discovery of glycerol phosphate and an immunogenic glycan motif in rhamnose-rich polysaccharides of Streptococcus uberis
Bibliographic record
Abstract
Streptococcus uberis is a causative pathogen of bovine mastitis with high genetic diversity. Rhamnose-rich polysaccharides (RPS) are abundant surface structures covalently anchored to peptidoglycan and represent promising vaccine candidates for several streptococcal pathogens. It was previously reported that the RPS of S. uberis strain 233 is composed of a repeating → 2)-α-L-Rhap-(1 → 3)-α-L-Rhap-(1 → disaccharide backbone decorated with α-D-Glcp side-chains. In this study, we identified a hitherto unknown glycerol phosphate (GroP) modification at the 6-OH of the Glc residue in S. uberis 233 RPS using nuclear magnetic resonance analysis. Comparative genomic analysis of 592 S. uberis genomes revealed significant diversity in the RPS biosynthesis gene cluster with six major RPS genotypes. RPS genotypes 1-4, representing 97.5% of the analyzed strains, all contained the rhamnan backbone biosynthesis genes shared between several streptococcal species, as well as a putative GroP transferase gene. Using rhamnan-reactive immune serum, we further demonstrated that rhamnan is a conserved and accessible glycan motif in S. uberis RPS genotype 1 and 2 strains, but this motif is inferred to be shielded by side-chains in genotype 4 strains. Importantly, experiments with sera from cattle, challenged intramammarily with S. uberis, revealed that the rhamnan backbone of S. uberis RPS is an immunogenic glycan motif and remained accessible to bovine IgG antibodies in the presence of single residue RPS side-chains. Overall, this study suggests that S. uberis RPS are modified with GroP and reports that RPS in most strains contain a conserved, immunogenic and antibody accessible rhamnan glycan motif.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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 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".