Understanding Type A Clostridium perfringens in Foal Necrotizing Enteritis and Canine Acute Hemorrhagic Diarrhea
Bibliographic record
Abstract
The role of type A Clostridium perfringens in foal necrotizing enteritis and canine acute hemorrhagic diarrhea is poorly understood. However, recently, we described a highly significant association between the presence of novel toxigenic C. perfringens and these specefic enteric diseases. These strains produce three novel putative toxins related to the beta-sheet pore-forming toxin family, which were designated NetE, NetF, and NetG. Our group demonstrated that NetF is likely the major virulence factor in strains responsible for canine acute hemorrhagic diarrhea and foal necrotizing enteritis. This thesis contains three studies aimed at expanding the understanding of netF-positive C. perfringens. In the first study, the genome of two NetF-producing strains, JFP838 and JFP55, which were isolated from cases of canine acute hemorrhagic diarrhea and foal necrotizing enteritis, respectively, were sequenced. Results of this research indicated that NetF and NetE were encoded by the same pathogenicity locus (NetF locus) on a tcp-conjugative plasmid and that NetG was encoded by a second plasmid (pNetG) on a unique pathogenicity locus (NetG locus). In addition, these two isolates shared three plasmids, including the netF/netE plasmid (pNetF), a cpe/cpb2 plasmid (pCPE), and a small bacteriocin-encoding plasmid (pBCN). In the second study, 30 NetF-producing strains were sequenced to determine whether the newly described pathogenicity loci are conserved, and all netF-positive isolates harbour the same plasmid profile. In addition, the genetic relatedness of these isolates were examined by core genome multilocus sequence typing (cgMLST). The bioinformatics analysis showed that in pNetF and pNetG, if present, pathogenicity loci are highly conserved among netF-positive strains. The common plasmid profile (pNetF, pCPE, and pBCN) was found in all NetF-producing strains and these strains were found to belong to two clonal populations. In the third study, pore-forming activity of the NetF toxin and the chemical nature of its receptor was investigated. The results demonstrated for the first time that NetF is able to create large pores on cell membranes and that its binding site is most likely a sialic acid-containing glycoprotein. Overall, this thesis has contributed significantly to the current knowledge of evolution, relationships, and pathogenesis of netF-positive C. perfringens infections.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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 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".