Time-lapse videomicroscopy of cell (spore) movement in red algae
Bibliographic record
Abstract
The red algae generally are considered to have no motile stages. We have confirmed sporadic reports of motile spores in a few red algae by recording freshly released live spores with time-lapse videomicroscopy. Of the 25+ species investigated, only a few had spores that appeared to be immobile. Cells of unicellular species often displayed active movement although were otherwise indistinguishable from nearby immobile cells, and these may be equivalent to the motile spores released after differentiation in more complex multicellular species. There was considerable variation among members of the Bangiophycidae. Cells of Porphyridium often moved at around 0·66 μm s1 and had conspicuous mucilage tails. Flintiella and Rhodospora showed no cellular movement. Rhodosorus sometimes moved a little and all four strains displayed continuous cytoplasmic rotation within the wall. Glaucosphaera was inert but displayed formation and transport of vesicles from the perinuclear region to the surface where they were discharged. Spores (whether monospores, tetraspores or carpospores) of almost all other species or strains available displayed various forms of motility. Some (e.g. Batrachospermum-Chantransia monospores) showed smooth, directional and continuous gliding (c. 2·2 μm s1) for shorter or longer distances, clearly detectable to the naked eye through the microscope. In others, movement could be almost as fast or slower, non-continuous and undirectional. Certain spores (e.g. monospores of the filamentous Audouinella sp.) were amoeboid, and in some cases (e.g. Sahlingia) cells actively squeezed through the irregular interstices of a crustose colony. The mechanism of movement is unknown; polysaccharide secretion may be involved in some cases. These forms of motility may be significant as dispersal mechanisms, by moving spores out of the stagnant boundary layer, and in settling processes, by allowing spores limited ability to optimize their site of germination.
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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 | 0.000 |
| 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".