Control of archaellation in <i>Sulfolobus acidocaldarius</i>: unravelling of the regulation of surface structure biosynthesis in Archaea begins
Bibliographic record
Abstract
Archaea have a variety of surface appendages including archaella (archaeal flagella), pili, hami and cannulae. While expected to be energetically expensive to express, studies focused on the regulation of such structures are nevertheless lacking. In the current issue of Molecular Microbiology, Reimann et al. (2012) identified a two-partner system called ArnA and ArnB in Sulfolobus acidocaldarius that interact strongly with each other and are repressors of archaella expression while also having an enhancing effect on the appearance of type IV pili. ArnA is a forkhead-associated domain-containing protein while ArnB is a von Willebrand domain-containing protein. Both proteins can be phosphorylated in vitro by S. acidocaldarius protein kinases. The repression of archaella expression is dependent on dephosphorylation of the Arn proteins. Deletions of arnA or arnB resulted in increased levels of archaella operon proteins and cells that were hypermotile due to increased archaellation. Direct effects of ArnA/ArnB on transcription from fla promoters were demonstrated using arnA and arnB deletion strains but only a modest increase in transcription was demonstrated in each mutant suggesting that the repression effect observed may be due to protein-protein interactions. This paper represents a significant step forward in our understanding of archaeal surface structure biogenesis.
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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 | 0.001 | 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".