Steroid hormones produced by coral-associated Endozoicomonas prime the coral immune response during thermal stress
Bibliographic record
Abstract
The coral microbiome is believed to play a critical role in sustaining corals and enabling adaptation to thermal stress. A ubiquitous group of coral-associated bacteria, known as Endozoicomonas, are hypothesized to provide essential metabolites to corals, though the exact roles these bacteria play during ambient or thermal stress conditions are largely unknown. We demonstrate that while Endozoicomonas synthesizes the iron-binding siderophore aerobactin in vitro, this trait may be suppressed in hospite. Integrated metagenomics, metabolomics, and lab validations reveal that within the coral holobiont Endozoicomonas is the only microbe capable of metabolizing coral-derived testosterone and converting ubiquitous cholesterol into testosterone and progesterone, important steroids that accumulate within the coral holobiont during thermal stress. Provision of testosterone and progesterone to corals during thermal stress induced transcriptional reprogramming of the coral innate immune response, promoting cellular survival and suggesting active microbial involvement in immune priming and stress resilience. These findings highlight a previously unrecognized mechanism of microbial contribution to coral resilience. Lastly, the capacity of bacteria to synthesize eukaryotic steroids implies deep evolutionary connections between microbial metabolism and the origin of steroid-mediated processes in early eukaryogenesis.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".