Presence of the Hmq system and production of 4-hydroxy-3-methyl-2-alkylquinolines is heterogeneously distributed between <i>Burkholderia cepacia</i> complex species and more prevalent among environmental than clinical isolates
Bibliographic record
Abstract
Abstract Some Burkholderia cepacia complex (Bcc) strains have been reported to produce 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), analogous to the 4-hydroxy-2-alkylquinolines of Pseudomonas aeruginosa . Using in silico analyses, we previously showed that the hmqABCDEFG operon, which encodes enzymes involved in the biosynthesis of HMAQs, is carried by about one-third of Bcc strains, with considerable inter- and intra-species variability. In the present study, we investigated by PCR, using consensus primers, the distribution of hmqABCDEFG in a collection of 313 Bcc strains (222 of clinical and 91 of environmental origins) - belonging to 18 Bcc species. We confirmed that the distribution is species-specific, although not all strains within a species carry the hmqABCDEFG operon. Among the 30% of strains bearing the hmqABCDEFG operon, we measured the total HMAQs production and showed that 90% of environmental isolates and 68% of clinically isolated Bcc produce detectable levels of HMAQs when cultured in TSB medium. For the strains having the hmqABCDEFG operon but not producing HMAQs, we studied the transcription and showed that none expressed the hmqA gene under the specified culture conditions. Interestingly, the hmqABCDEFG operon is more prevalent among plant root environment species (e.g. B. ambifaria, B. cepacia ) and absent in species commonly found in chronically colonized individuals with cystic fibrosis (e.g. B. cenocepacia, B. multivorans ), suggesting that the Hmq system could play a role in niche adaptation by influencing rhizosphere microbial community and could have been lost through evolution. Understanding the Hmq system and its regulation will provide clues concerning the production of HMAQs and their functions in Bcc.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".