Electroporation transformation of FITC-dextran into Oxyrrhis marina - an early branching dinoflagellate. v3
Bibliographic record
Abstract
INTRODUCTION Here we describe a protocol for transforming Oxyrrhis marina with FITC-labelled dextran (a DNA analog) by electroporation. This protocol is reproducible, and results in a transformation efficiency of around 1%. We have confirmed the viability of transformed cells by allowing them to recover in the dark (and thus maintain fluorescence intensity) and then by observing fluorescent cells swimming normally, days after transformation (see the videohere). NOTE ON AUTOFLUORESCENCE Although Oxyrrhis is a non-photosynthetic dinoflagellate and therefore lacks plastid autofluorescence, we have observed a small amount of green autofluorescence that is typically isolated in the anterior of the cell (See top panel of Figure 1). The autofluorescence was observed in wildtype cells, cells electroporated without FITC-dextran, and cells that were incubated with FITC-dextran but not electroporated. The autofluorescence was observed in cultures with both Dunaliella tertiolecta or heat-killed E. coli. The brightness and frequency of the autofluorescence also seemed to be dependent on culture conditions. Not all cells had the autofluorescence. ADDITIONAL INFORMATION As of yet we have been unable to demonstrate the actual uptake of plasmid DNA. We have tried using rhodamine labelled plasmids to demonstrate this but the results were inconclusive due to issues with cellular autofluorescence. We have also tried this method with a variety of expression plasmidsencoding different promoters. For example, we tried the MOE promoter fromPerkinsus marinus(a closely related species) and the generic eukaryotic CMV promoter. However no GFP fluorescence was detected in these samples. We have also tried transformingin vitro synthesized GFP encoding mRNA using this protocol. As of yet, no GFP production has been detected, but this may reflect non-cannonical translational systems in dinoflagellates as the same mRNA could be translated in starfish embryos. Although the development of expression systems in dinoflagellates remains a challenge, our results suggest thatO. marina may be amenable to genetic transformation.
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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) | 0.001 | 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 | 0.001 |
| 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".