Molecular investigation of larval development and metamorphosis in the American Lobster, Homarus americanus
Bibliographic record
Abstract
The American lobster, Homarus americanus, is a marine decapod crustacean that\noccurs naturally in the coastal waters o f eastern North America. High concentrations of\nlobster in the Gulf of Maine to the Gulf of St. Lawrence support a significant fishing\nindustry in Atlantic Canada and the northeastern United States. A hard exoskeleton\ncovers and protects H. americanus, which they periodically moult to facilitate growth. H.\namericanus has a complex life history, including a pelagic larval phase and a benthic\nadult phase. The larval phase is divided into three morphologically distinct stages,\nfollowed by metamorphosis to the postlarval phase. Larvae must moult to progress\nthrough each developmental stage. Previous studies have described several\nmorphological, physiological, biochemical and behavioural changes associated with\nmoult, growth and development o f H. americanus. However, the mechanisms that\nregulate these changes are not fully elucidated. This was the first study to use a 14,592 feature, spotted oligonucleotide microarray, to investigate global gene expression changes during H. americanus larval\ndevelopment. Public molecular databases were used to functionally annotate -40% o f\nthe EST sequences. A reference design was used to compare stage specific gene\nexpression profiles of larvae and postlarvae from two year classes. A two-way ANOVA\nwas used to determine significant differences in gene expression levels among the stages\nand year classes. This study found that the expression of 1,851 genes was significantly\ndifferent among larval stages, although 771 genes had significant interaction between\nyear classes and larval stages. Among the differentially expressed genes, functional\nannotations indicated that several genes were involved with the immune system, energy regulation and development. Ten target genes of interest were selected, based on functional annotations, for expression verification using a complementary measurement method, reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Genes\nwith functional annotations related to immunity, energy regulation, gene expression,\ntranslation and neural or basement membrane remodeling were selected. Two\nPhosphoenolpyruvate carboxykinases, Argonaute 2, Ecdysone inducible protein 75 and\nProcollagen-lysine 2-oxoglutarate 5-dioxygenase 3, were significantly different (P <\n0.05) genes of interest among stages when assayed using RT-qPCR. These genes are\ninvolved with processes that may greatly impact development such as, translation\nregulation, gene expression, morphological development and energy metabolism.\nWith increasing interest in the sustainability of the American lobster fishery, this\nstudy has provided an important foundation for future investigations of processes\nregarding signaling, morphological re-modeling, energy metabolism, and the immune\nsystem as they pertain to larval development. Understanding the mechanisms that\nregulate larval development may give insight into the effects factors such as climate\nchange and anthropomorphic environmental impacts have on early life stages of H.\namericanus.
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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".