Cadmium spurred Microcystis aeruginosa to unleash more toxic metabolites
Bibliographic record
Abstract
Cyanobacterial harmful algal blooms (cHABs), normally dominated by Microcystis aeruginosa , pose a threat to aquatic ecosystems due to the release of various harmful metabolites. Cadmium (Cd), a heavy metal commonly found in surface water and sediments, often coincides with cHABs in eutrophic lakes. However, the ecotoxicological effects of Cd on M. aeruginosa and the potential for combined toxicity are not yet fully understood. In this study, we determined the effective concentrations of cadmium from 10 % (EC 10 ) to 50 % (EC 50 ) for M. aeruginosa based on cell density inhibition. We then conducted a combined analysis focusing on the impact of a low dose Cd (EC 10 , 139 μg/L) on the physiological factors, transcriptome and both intracellular and extracellular metabolites of M. aeruginosa. We found that Cd treatment decreased M. aeruginosa chlorophyll a content by 24.5 %, which coincided with the suppression of genes linked to ribosomal and photosynthesis pathways. However, Cd exposure stimulated the synthesis and extracellular release of cellular compounds by enhancing amino acid and carbohydrate metabolism. This led to elevated extracellular levels of amino acids, organic acids, and secondary metabolites - including peptides, lipids, benzenoids, terpenes, sterols, and glycosides - which could serve as potential toxic metabolites of cyanobacteria. These changes were driven by the activation of osmoregulatory mechanisms, antioxidant-related amino acids, and ATP-binding cassette transport and secretion systems. Our research indicated that low Cd concentrations could stimulate the synthesis and release of toxic metabolites and exacerbate cHAB threats in eutrophic lakes, underscoring the importance of addressing multiple stressors in freshwater environments. • Cd inhibited M. aeruginosa growth by suppressing gene expression in ribosome and photosynthesis. • Cd stimulated compound synthesis/release in M. aeruginosa by activating amino acid and ABC transport. • Cadmium increased ecological risks of M. aeruginosa by releasing more toxic compounds.
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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".