Galactose Metabolism and Capsule Formation in a Recombinant Strain of Streptococcus thermophilus with a Galactose-Fermenting Phenotype
Bibliographic record
Abstract
The capsule-producing, galactose-negative Streptococcus thermophilus MR-1C strain was first transformed with a low-copy plasmid containing a functional galK gene from Streptococcus salivarius to generate a recombinant galactose-fermenting Strep. thermophilus strain named MR-AAC. Then, we compared the functional properties of Strep. thermophilus MR-AAC with those of the parent MR-1C strain when used as starter for fermented products and cheese. In lactose-supplemented laboratory medium, MR-AAC metabolized galactose, but only when the amount of lactose was less than 0.1% (wt/vol). After 7 h of fermentation, the medium was almost depleted of galactose. The parent strain, MR-1C, showed the same pattern, except that the concentration of galactose decreased by only 25% during the same period. It was found that, during milk fermentation and Mozzarella cheese production, the galactose-fermenting phenotype was not expressed by MR-AAC and this strain expelled galactose into the medium at a level similar to the parent MR-1C strain. In milk and in lactose-supplemented medium, capsular exopolysaccharide production occurred mainly during the late exponential phase and the stationary growth phase with similar kinetics between MR-1C and MR-AAC.
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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 | 0.000 | 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 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".