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Ultrastructural effect of penicillin and cycloheximide on Chlamydia trachomatis strain HAR-13
Abstract:
The effect of cycloheximide and penicillin on the ultrastructural morphology of C. trachomatis strain HAR-13 was examined by electron microscopy. HAR-13 infected McCoy cells were either treated with cycloheximide (1 microgram/ml) or cycloheximide (1 microgram/ml) plus penicillin G (100 U/ml). The studies revealed that cycloheximide alone induced no morphological alterations into the ultrastructure of HAR-13. Both HAR-13 developmental forms, the elementary body and reticulate body, were present inside the treated McCoy cells. The elementary bodies contained the central dense nucleoid and were about 0.3 microns in diameter, while the reticulate bodies were of typical gram negative bacterial morphology and were from 0.5-1.0 microns in diameter. Cycloheximide in combined treatment with pencillin produced giant, swollen reticulate bodies that were 2-4 microns in diameter and in some cases vacuolated. Elementary bodies were noticeably absent. These results indicate that cycloheximide does not alter the morphology of HAR-13. This system is a useful model for studying the ultrastructural morphology of C. trachomatis strain HAR-13.
Insights
Cycloheximide alone does not change Chlamydia trachomatis (C. trachomatis) morphology. However, combined with penicillin, it causes significant swelling of reticulate bodies and eliminates elementary bodies.
Area of Science:
- Microbiology
- Cell Biology
- Infectious Diseases
Background:
- Chlamydia trachomatis (C. trachomatis) is an obligate intracellular bacterium.
- Understanding C. trachomatis developmental cycle and morphology is crucial for developing effective treatments.
- McCoy cells are commonly used for C. trachomatis culture and study.
Purpose of the Study:
- To investigate the ultrastructural effects of cycloheximide and penicillin on C. trachomatis strain HAR-13.
- To evaluate cycloheximide as a standalone agent and in combination with penicillin on C. trachomatis morphology.
Main Methods:
- McCoy cells infected with C. trachomatis strain HAR-13 were treated with cycloheximide alone or with penicillin G.
- Ultrastructural morphology was examined using electron microscopy.
Main Results:
- Cycloheximide alone did not induce morphological alterations in C. trachomatis, with both elementary and reticulate bodies observed.
- Combined treatment with cycloheximide and penicillin resulted in giant, swollen reticulate bodies (2-4 microns) and absence of elementary bodies.
- Reticulate bodies in combined treatment showed vacuolation in some instances.
Conclusions:
- Cycloheximide does not alter the intrinsic ultrastructural morphology of C. trachomatis.
- The combination of cycloheximide and penicillin significantly impacts C. trachomatis reticulate body development.
- This experimental system provides a valuable model for studying C. trachomatis ultrastructural changes.