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Updated: Jul 20, 2026
10:35
Markerless Gene Deletion by Floxed Cassette Allelic Exchange Mutagenesis in Chlamydia trachomatis
Published on: January 30, 2020
The effect of penicillin on Chlamydia trachomatis DNA replication
Paul R Lambden1, Mark A Pickett1, Ian N Clarke1
1Molecular Microbiology Group, University of Southampton Medical School, MP814, Southampton General Hospital, Hampshire SO16 6YD, UK.
Microbiology (Reading, England)
|September 2, 2006
Summary
Penicillin treatment of Chlamydia trachomatis-infected cells halts bacterial development but not DNA replication. Aberrant reticulate bodies (RBs) continue replicating DNA extensively within host cells.
Area of Science:
- Microbiology
- Cell Biology
- Molecular Biology
Background:
- Chlamydia trachomatis is an obligate intracellular bacterium with a complex developmental cycle.
- Understanding the mechanisms regulating Chlamydia replication is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the effects of penicillin on Chlamydia trachomatis L2 replication and development.
- To analyze DNA replication dynamics in the presence of penicillin.
Main Methods:
- Infection of BGMK cells with Chlamydia trachomatis L2 at a multiplicity of infection (m.o.i.) of 1.0.
- Transmission electron microscopy and quantitative PCR (QPCR) for chromosomal and plasmid DNA.
- Addition of penicillin at 20 hours post-infection (p.i.) to assess its impact on the developmental cycle.
Main Results:
- Chlamydia trachomatis DNA replication occurred in two phases: slow (0-18 h) and rapid (18-36 h) with a doubling time of 4.6 h.
- Penicillin blocked binary fission and reticulate body (RB) to elementary body (EB) transition but did not inhibit chromosomal or plasmid DNA replication.
- Aberrant RBs formed large inclusions, continued DNA replication beyond the normal cycle, with up to 16 chromosomal copies per RB at 60 h p.i.
Conclusions:
- Penicillin disrupts Chlamydia trachomatis development by inhibiting cell division and differentiation, not DNA replication.
- Aberrant RBs can sustain extensive DNA replication in the absence of normal development.
- These findings offer insights into Chlamydia's adaptability and potential therapeutic targets.
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