<i>Chlamydia suis</i>displays high transformation capacity with complete cloning vector integration into the chromosomal<i>rrn-nqrF</i>plasticity zone
Bibliographic record
Abstract
ABSTRACT Chlamydia, comprising several human and zoonotic pathogens, is a genus of the conserved bacterial phylum Chlamydiota. Their obligate intracellular niche serves as a barrier for natural genetic exchange via horizontal gene transfer (HGT), and further limits the development and application of genetic tools. To date, the only example for recent inter-phylum HGT among the Chlamydiota is tetracycline resistance in the potentially zoonotic speciesChlamydia suis, a close phylogenetic relative of humanC. trachomatis, which causes bacterial sexually transmitted infections and ocular trachoma. Tetracycline resistance in porcineC. suisstrains has been described worldwide and is always part of a genomic island dividinginvasin(inv), located within a chromosomal region between the rRNA operon (rrn) and thenqrFreductase. Here, we aimed to expand the still modest number of available genetic manipulation systems forChlamydiaby generating allele-replacement and integration vectors forC. suis. These vectors comprised homologousC. suissequences of the chromosomal region of interest, anE. coliorigin of replication (ori) and selection markers but lacked the native chlamydial plasmids or itsori. We first recovered allele-replacement mutants using a vector that targets the tryptophan (trp) operon ofC. suis. The vector was further successfully maintained as a free plasmid inC. trachomatiswithout allele replacement, suggesting complex plasmid dynamics in the absence of a chlamydialori. Moreover, we showed that the hypervariablerrn-nqrFintergenic region ofC. suisis highly susceptible to transformation, resulting in complete vector integration upstream ofnqrFwithout interruption of the targetedinvgene. IMPORTANCE The obligate intracellularChlamydiagenus contains many pathogens with a negative impact on global health and economy. Despite recent progress, there is still a lack of genetic tools limiting our understanding of these complex bacteria. This study provides new insights into genetic manipulation ofChlamydiawith the opportunistic porcine pathogenChlamydia suis, the only chlamydial species naturally harboring an antibiotic resistance gene, originally obtained by horizontal gene transfer.C. suisis transmissible to humans, posing a potential public health concern. We report thatC. suiscan take up vectors that lack the native plasmid, a requirement for most chlamydial transformation systems described to date. Additionally, we show thatC. trachomatis, the most common cause for bacterial sexually transmitted infections and infectious blindness worldwide, can be transformed withC. suisvectors. Finally, the chromosomal region that harbors the resistance gene ofC. suisis highly susceptible to complete vector integration.
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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 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".