Analysis of the Ketosynthase Genes in Streptomyces and Its Implications for Preventing Reinvestigation of Polyketides with Bioactivities
Bibliographic record
Abstract
Cucumber wilt by Fusarium oxysporium f sp. cucumarinum is one of the most important soil-borne diseases. Among control strategies for plant soil-borne pathogen, biocontrol systems eliminate neither pathogen nor disease but bring them into natural balance. Polyketides form the largest part of the known natural products, and most of them come from actinomycetes especially streptomyces. Analysis for the ketosynthase genes in streptomyces can implicate new polyketides. In the course of the screening for producers of polyketides with antifungal activities, 117 strains were isolated. The screening program was performed by means of PCR amplification using degenerated primers corresponding to type II ketosynthase (KS) genes. Among 117 isolates, 33 isolates showed antifungal activities and 17 isolates showed positive amplification signal. Antagonism of the 17 isolates against Fusarium oxysporium f sp. cucumarinum, Bacillus subtilis and Erwinia carotovora subsp. carotovora in vitro were analyzed. The diversities of KS-II gene from the 17 isolates were abundant based on phylogenetic tree analysis. The 17 isolates were divided into 6 clades based on KS-II gene sequence. The results showed that different isolates which belong to the same species present different antagonism activities and also the different streptomyces species showed different bioactivities. Among 17 isolates, isolates DQ1, DQ23, GAN1, HVG60 and HVG71 have the potential ability to produce new type polyketides. This method may not only prevent reinvestigation to find bioactive molecules described previously, but also alleviate some of the biases introduced by using conventional cultivation techniques.
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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 | 0.001 | 0.001 |
| 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".