Bibliographic record
Abstract
Ergosterol and fatty acids for biomass estimation of mycorrhizal fungi are discussed in a New Phytologist article by Olsson et al. (2003). The findings indicate that arbuscular mycorrhizal fungi (AMF) do not contain ergosterol and thus cannot be assessed using an ergosterol assay. This speaks directly to a recent study in which we used ergosterol analysis to estimate living AMF biomass in the root and soil (Hart & Reader, 2002a,b). The results of Olsson et al. suggest that our results do not reflect AMF colonization but rather colonization by nonglomalean fungi. We feel that our results do reflect AMF activity for the following reasons. First, our ergosterol measurements were extremely low in nonAMF treatments, thus it is unlikely that there was a high degree of contamination solely in AMF treatments. Second, our ergosterol measurements were almost perfectly correlated with measures of per cent root length colonization (using uniquely AMF structures) and soil hyphal length (Hart & Reader, 2002b). Finally, because our results showed high ergosterol in roots for the Glomaceae and high ergosterol in soil for the Gigasporaceae, the results of Olsson et al. would suggest that contamination in our study mirrored the pattern of AMF colonization. If this were the case, and contaminating fungi were so closely associated with AMF, then ergosterol would still provide a good, if indirect, estimate of AMF activity. Olsson et al. have shown that, in vitro, two AMF isolates contain little ergosterol. In the future, it will be important to examine more isolates and more species. It remains to be seen how ergosterol production is affected by edaphic conditions because monoxenic cultures do not reflect the way in which AMF behave under natural conditions. More work needs to be done to discover the true origin of ergosterol in such studies. Is the ergosterol contaminant in origin and, if so, how is it so closely linked to AMF colonization? Or do AMF in soil behave very differently to monoxenic cultures?
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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 | 0.011 | 0.006 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.002 |
| Bibliometrics | 0.004 | 0.003 |
| Science and technology studies | 0.001 | 0.007 |
| Scholarly communication | 0.007 | 0.033 |
| Open science | 0.003 | 0.006 |
| Research integrity | 0.014 | 0.018 |
| Insufficient payload (model declined to judge) | 0.009 | 0.006 |
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".