Role of antioxidant defenses during estivation and anoxia exposure in the freshwater snail<i>Biomphalaria tenagophila</i>(Orbigny, 1835)
Bibliographic record
Abstract
The effects of 24 h of exposure to underwater anoxia and 15 days of estivation (at 2627°C) on the enzymatic antioxidant system of the hepatopancreas of the freshwater snail Biomphalaria tenagophila (Planorbidae) are described. The effect of 24 h of recovery was also investigated. Catalase activity dropped by 31% during 24 h of anoxia, and superoxide dismutase (SOD) activity was reduced by 43% during the 15 days of estivation. This is consistent with the overall decrease in metabolic rate during estivation or anoxia. Indeed, the heartbeat diminished by 2836% during estivation (determination was possible for only 4 days) and by 66% after 24 h of anoxia. On the other hand, selenium-dependent glutathione peroxidase (Se-GPX) activity increased during anoxia (from 10 to 14 mU/mg protein) and estivation (by 14%). Glutathione S-transferase (GST) and glutathione reductase activities remained unchanged during estivation and anoxia. Glucose 6-phosphate dehydrogenase activity was unchanged during estivation and recovery. Recovery restored SOD activity. Catalase, Se-GPX, and GST activities during recovery were significantly lower than those of the respective controls. Lipid peroxidation, determined as the level of thiobarbituric acid-reactive substances, was unchanged in the hepatopancreas after 15 days of estivation and 26 h of recovery from estivation. It is possible that the increase in Se-GPX activity during anoxia and estivation, and the maintenance of GST activity, are relevant in minimizing the effects of reactive oxygen species that can be formed upon resumption of aerobic metabolism. Thus, B. tenagophila may have a biochemical strategy of preparation for oxidative stress such as that observed in several other species of anoxia/hypoxia-tolerant animals.
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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) | 0.001 | 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".