Design of Bacterial Hosts for lac-Based Expression Vectors
Bibliographic record
Abstract
Since introduction of the first pUC plasmids (1), a great variety of plasmid vectors that use α-complementation and expression from the lac promoter, or its derivatives tac and trc promoters, have been developed (e.g., see refs. 2–14). In order to maximize utilization of these vectors, various Escherichia coli host strains have been designed which contain the lacZΔM15 allele (15) necessary for α-complementation and the lacI q (16,17) gene, which allows for overproduction of the lac repressor that is required for regulated expression from the lac promoter. The development of F episomes (7,14,18) or phages (1,19) containing these components facilitated the construction of various host strains, provided they do not express β-galactosidase (e.g., Δlac strains). However, these systems suffer from several short-comings that restrict their use:
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 | 0.000 | 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) | 0.001 | 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 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".