New methods for the isolation of skeletal muscle sarcolemma and sarcoplasmic reticulum allowing a comparison between the mammalian and amphibian β<sub>2</sub>‐adrenergic receptors and calcium pumps
Bibliographic record
Abstract
New methods were established for the rapid and simultaneous isolation of multiple sarcolemmal and sarcoplasmic reticular fractions from very small amounts (0.25-2.0 g) of skeletal muscle. Thebeta(2)-adrenergic receptor and calcium transport systems were used as indices of purity and functional integrity as well as being the focal points of the study. These methods were found to be suitable for the special needs of small tissue samples, allowed rapid preparation and were appropriate for skeletal muscle from various species, frogs to mammals. The sarcolemmalbeta(2)-adrenergic receptor was expressed in frogs and mammals at similar levels of expression (336-454 fmol. x mg(-1)). The calcium pump was also present in sarcolemmal and sarcoplasmic reticular fractions in all species but notable species differences were found. In sarcolemmal fractions, while calcium binding was uniformly low (<1 nmol. x mg(-1)), oxalate stimulation was variable: low in frogs ( approximately 1.05-fold) high in mammals (120-450-fold). In sarcoplasmic reticular fractions, calcium binding was low in frogs (4-9 nmol. x mg(-1)) and much higher in mammals (322-383 nmol. x mg(-1)); oxalate stimulated calcium transport to a much greater extent in frogs (<70-fold) than in mammals (1.6-2-fold). It is concluded that thebeta(2)-adrenergic receptor appears to be strongly conserved in skeletal muscle while the use of calcium pumps evolves from reliance in Amphibia on the sarcoplasmic reticular calcium pump to the use in Mammalia of calcium pumps from both the sarcoplasmic reticulum and the plasma membrane.
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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) | 0.000 | 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 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".