Identification and Characterization of a Membrane Permease Involved in Iron-Hydroxamate Transport in <i>Staphylococcus aureus</i>
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Staphylococcus aureus was shown to transport iron complexed to a variety of hydroxamate type siderophores, including ferrichrome, aerobactin, and desferrioxamine. An S. aureus mutant defective in the ability to transport ferric hydroxamate complexes was isolated from a Tn917-LTV1 transposon insertion library after selection on iron-limited media containing aerobactin and streptonigrin. Chromosomal DNA flanking the Tn917-LTV1 insertion was identified by sequencing of chromosomal DNA isolated from the mutant. This information localized the transposon insertion to a gene whose predicted product shares significant similarity with FhuG of Bacillus subtilis. DNA sequence information was then used to clone a larger fragment of DNA surrounding the fhuG gene, and this resulted in the identification of an operon of three genes, fhuCBG, all of which show significant similarities to ferric hydroxamate uptake (fhu) genes in B. subtilis. FhuB and FhuG are highly hydrophobic, suggesting that they are embedded within the cytoplasmic membrane, while FhuC shares significant homology with ATP-binding proteins. Given this, the S. aureus FhuCBG proteins were predicted to be part of a binding protein-dependent transport system for ferric hydroxamates. Exogenous iron levels were shown to regulate ferric hydroxamate uptake in S. aureus. This regulation is attributable to Fur in S. aureus because a strain containing an insertionally inactivated fur gene showed maximal levels of ferric hydroxamate uptake even when the cells were grown under iron-replete conditions. By using the Fur titration assay, it was shown that the Fur box sequences upstream of fhuCBG are recognized by the Escherichia coli Fur protein.
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.
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 | 0.000 | 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 it