Enterocyte proliferation and apoptosis in the caudal small intestine is influenced by the composition of colonizing commensal bacteria in the neonatal gnotobiotic pig
Bibliographic record
Abstract
We previously reported marked differences in small intestinal morphology, including changes in crypt depth and villous height, after inoculation of germ-free pigs with different bacterial species. In an attempt to identify the mechanisms governing changes in villous morphology associated with bacterial colonization, 2 gnotobiotic experiments were performed. In each experiment, 16 piglets were allocated to 4 treatment groups including germ-free (GF), monoassociation with Lactobacillus fermentum (LF) or Escherichia coli (EC), or conventionalized with sow feces (SF). Piglets were reared under gnotobiotic conditions until 14 d of age, at which time whole intestinal tissue and enterocytes were collected for histological, gene expression, and protein analysis. Proliferating cell nuclear antigen, tumor necrosis factor alpha (TNFalpha), Fas ligand (FasL), CD3epsilon, caspase 3 (casp3), and toll-like receptors (TLR)2, 4, and 9 expression were measured by quantitative PCR. Activated casp3 was measured by Western blot. Increased abundance of activated casp3 and transcripts encoding proliferating cell nuclear antigen, TNFalpha, CD3epsilon, and FasL was observed in SF and EC treatment groups compared with GF and LF. Expression of TLR2 was increased (P < 0.05) in the SF treatment and tended to be greater (P < 0.08) in EC relative to LF and GF. Results indicate that conventional bacteria and E. coli but not L. fermentum increase overall cell turnover by stimulating increased apoptosis through the expression of FasL and TNFalpha and by increasing cell proliferation. The differential regulation of TLR expression indicates that microbially induced changes may be mediated in part by these receptors. Induction of inflammatory responses and activation of apoptosis through death receptors appears to play a significant role in enterocyte turnover mediated by commensal bacteria.
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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 | 0.001 |
| 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".