Do polyamines modulate the Lotus glaber NADPH oxidation activity induced by the herbicide methyl viologen?
Bibliographic record
Abstract
In recent years, there has been a growing interest in NADPH-oxidases which are involved in the active generation of reactive oxygen species (ROS), owing to their role in oxidative burst, signalling and oxidative damage derived from biotic and abiotic stresses. NADPH oxidase activity is enhanced by some environmental cues, such as zinc deficiency and chilling stress, where zinc and polyamines have been suggested to be involved in the modulation of ROS generation. In order to further characterise NADPH oxidation activity during oxidative stress we exposed Lotus glaber Mill. (narrow-leaf trefoil; syn. L. tenuis Waldst. et Kit. ex Wild var. Miller) plants to the herbicide methyl viologen (MV) and evaluated zinc and polyamines as oxidative stress regulatory compounds. For this purpose we conducted in vitro and in vivo experiments, observing that zinc and the higher polyamines spermidine and spermine inhibited the NADPH oxidation activity in vitro while preventing methyl viologen-induced superoxide production in vivo. It is suggested that these substances act through a direct effect on flavin oxidases. However, it was not possible to correlate free polyamine content of L. glaber with their hypothetical inhibitory role during oxidative stress, probably owing to the plant's natural tolerance to the herbicide tested. Therefore, tobacco, a more sensitive species, was tested for methyl viologen toxicity. High concentrations of methyl viologen induced free polyamine levels in crude extracts and intercellular fluids. However, only free polyamine content in the intercellular fluids was increased in plants treated with low methyl viologen concentrations. These results support the notion that polyamine metabolism in the apoplast is involved in the physiological response to oxidative stress.
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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".