<i>Burkholderia thailandensis oacA</i> Mutants Facilitate the Expression of <i>Burkholderia mallei</i> -Like O Polysaccharides
Bibliographic record
Abstract
Previous studies have shown that the O polysaccharides (OPS) expressed by Burkholderia mallei are similar to those produced by Burkholderia thailandensis except that they lack the 4-O-acetyl modifications on their 6-deoxy-α-l-talopyranosyl residues. In the present study, we describe the identification and characterization of an open reading frame, designated oacA, expressed by B. thailandensis that accounts for this phenomenon. Utilizing the B. thailandensis and B. mallei lipopolysaccharide (LPS)-specific monoclonal antibodies Pp-PS-W and 3D11, Western immunoblot analyses demonstrated that the LPS antigens expressed by the oacA mutant, B. thailandensis ZT0715, were antigenically similar to those produced by B. mallei ATCC 23344. In addition, immunoblot analyses demonstrated that when B. mallei ATCC 23344 was complemented in trans with oacA, it synthesized B. thailandensis-like LPS antigens. To elucidate the structure of the OPS moieties expressed by ZT0715, purified samples were analyzed via nuclear magnetic resonance spectroscopy. As predicted, these studies demonstrated that the loss of OacA activity influenced the O acetylation phenotype of the OPS moieties. Unexpectedly, however, the results indicated that the O methylation status of the OPS antigens was also affected by the loss of OacA activity. Nonetheless, it was revealed that the LPS moieties expressed by the oacA mutant reacted strongly with the B. mallei LPS-specific protective monoclonal antibody 9C1-2. Based on these findings, it appears that OacA is required for the 4-O acetylation and 2-O methylation of B. thailandensis OPS antigens and that ZT0715 may provide a safe and cost-effective source of B. mallei-like OPS to facilitate the synthesis of glanders subunit vaccine candidates.
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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".