Beating anoxia: mitochondrial plasticity in the turtle heart
Bibliographic record
Abstract
Freshwater turtles can survive without oxygen for several months. The cellular mechanisms that allow the turtle heart to survive without oxygen have remained almost totally unexplored. In particular, it is not known how the turtle heart avoids anoxic damage to the mitochondria. The objective of this study was to make a comprehensive analysis of mitochondrial function in chronically and acutely anoxic mitochondria from the heart of Trachemys scripta . Turtles were acclimated to 5°C under either normoxic or anoxic (2 weeks) conditions. Mitochondrial respiration, electron transport chain (ETC) activities, ADP affinity, enzyme activities, proton leak and membrane potential were measured in permeabilized cardiac fibres and isolated mitochondria. 2 weeks of anoxia led to a decrease in aerobic capacity and an increase in proton conductance (proton leak) of the mitochondrial membrane. The mechanism behind this plasticity was a downregulation of Complex V in the ETC. This strategy serves two purposes; to conserve ATP when energy is limited and to reduce the production of reactive oxygen species. Turtle heart mitochondria endured 20 min of simulated anoxia followed by reperfusion without any impact on subsequent ADP stimulated oxygen consumption, State IV respiration or respiratory control ratio. Thus, turtle mitochondria are robust and intrinsically tolerant to anoxia/reoxygenation.
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 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".