The production of 4-adminobutyrate in response to treatments reducing cytosolic pH and the regulation of intracellular pH
Bibliographic record
Abstract
GABA (4-aminobutyrate) is synthesized through the decarboxylation of LGlu- \n(L-Glu-+ H+ ---> GABA + C02), and compared to many free amino acids is \npresent in high concentrations in plant cells. GABA levels rise rapidly and \ndramatically in response to varied stress conditions including anaerobiosis. \nRecent papers suggest that GABA production and associated H+ consumption are \nparts of a metabolic pH-stat mechanism which ameliorates the intracellular pH \ndecline associated with anaerobiosis or other treatments. To test this hypothesis \nGABA production and efflux have been measured in isolated Asparagus sprengeri \ncells in response to three treatments which potentially cause intracellular \nacidification. Acid loads were imposed using 60 min of (i) anaerobiosis, (ii) H+/LGlu- \ncotransport, and (iii) treatment with permeant weak acids (butyric, acetic and \npropionic). Both intra- and extracellular GABA concentrations increased more than \n100% after anaerobiosis, almost 1000% after H+/L-Glu- cotransport (light or dark) \nand almost 5000/0 after addition of 5 mM butyric acid at pH 5.0. HPLC analysis of \namino acids indicates that as GABA concentrations increased in response to \nbutyric acid addition, glutamate concentrations decreased. Time-course studies \ndemonstrated that added butyric acid stimulates GABA production by 2800/0 within \n15 seconds. A fluorescent determination of cytosolic pH indicates that addition of \nbutyric or other weak acids resulted in a rapid reduction in cytosolic pH of 0.6 pH \nunits. The half time for the response to butyric acid addition is 2.1 seconds, \nindicating that the decline in cytosolic pH is rapid enough to account for the rapid \nstimulation of GABA production. The acid load in response to butyric acid addition \nwas assayed by measurements of 14C-butyric acid uptake. Calculations indicate \nthat GABA production accounted for 45% of the imposed acid load. The biological \nsignificance of GABA efflux is not yet understood. The results support the original \nhypothesis suggesting a role for GABA production in cellular pH regulation.
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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 | 0.001 |
| 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".