Ultrastructural Analysis of Differentiation in <i>Legionella pneumophila</i>
Why this work is in the frame
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Bibliographic record
Abstract
Legionella pneumophila is an adaptive pathogen that replicates in the intracellular environment of fundamentally divergent hosts (freshwater protozoa and mammalian cells) and is capable of surviving long periods of starvation in water when between hosts. Physiological adaptation to these quite diverse environments seems to be accompanied by morphological changes (Garduño et al., p. 82-85, in Marre et al., ed., Legionella, 2001) and conceivably involves developmental differentiation. In following the fine-structural pathway of L. pneumophila through both in vitro and in vivo growth cycles, we have now discovered that this bacterium displays an unprecedented number of morphological forms, as revealed in ultrathin sections and freeze-fracture replicas for transmission electron microscopy. Many of the forms were identified by the obvious ultrastructural properties of their cell envelope, which included changes in the relative opaqueness of membrane leaflets, vesiculation, and/or profuse invagination of the inner membrane. These changes were best documented with image analysis software to obtain intensity tracings of the envelope in cross sections. Also prominent were changes in the distribution of intramembranous particles (clearly revealed in replicas of freeze-fractured specimens) and the formation of cytoplasmic inclusions. Our results confirm that L. pneumophila is a highly pleomorphic bacterium and clarify some early observations suggesting sporogenic differentiation in L. pneumophila. Since morphological changes occurred in a conserved sequence within the growth cycle, our results also provide strong evidence for the existence of a developmental cycle in L. pneumophila that is likely accompanied by profound physiological alterations and stage-specific patterns of gene expression.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 it