Mycoplasma bovis-generated reactive oxygen species and induced apoptosis in bovine mammary epithelial cell cultures
Bibliographic record
Abstract
Mycoplasma bovis is an important cause of bovine mastitis in China and worldwide. We hypothesized that M. bovis damages bovine mammary epithelial cells (bMEC), with the degree of damage varying among field isolates. Our objective was to evaluate 2 novel sequence type (ST) field strains of M. bovis (ST172 and ST173) for their ability to induce oxidative stress, cytotoxicity, pathomorphological changes, and apoptosis in bMEC, as a model for pathogenesis of M. bovis-induced bovine mastitis. Cytotoxicity (as indicated by release of lactate dehydrogenase, LDH) from bMEC depended on multiplicity of infection (MOI), with a high MOI (1:1,000) being required to induce cytotoxicity. Morphological changes in bMEC, including shrinkage, loss of cell integrity, and heavy staining (hematoxylin and eosin) of cytoplasm were apparent 24 h after infection with ST172 or ST173 M. bovis, with more severe changes being induced by the latter strain. Adhesion and invasion assays both had curvilinear patterns, peaking 12 h after infection with MOI of 1:1,000. Both production of reactive oxygen species (ROS) and proportion of apoptotic cells increased with time after infection. Increased Bax/Bcl-2 ratios and activation of caspase-3 implied involvement of mitochondria-dependent pathways of apoptosis. Furthermore, intracellular ROS generation, apoptosis, and cleaved caspase-3 were mitigated by N-acetyl-l-cysteine, a ROS scavenger. Both interleukin (IL)-1β and IL-6 were significantly upregulated by ST172 and ST173 M. bovis, with little change in expression of tumor necrosis factor-α. One ST173 M. bovis isolate had the greatest cytotoxicity of all of our field isolates, with the highest LDH release, adhesion, invasion, ROS production, and apoptosis. In conclusion, our hypothesis was supported: M. bovis damaged bMEC by generating ROS and initiating a mitochondria-dependent pathway of apoptosis, with the degree of damage varying among field isolates. This study provided new knowledge regarding pathogenesis of M. bovis-induced bovine mastitis.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 teacher head, 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".