Abstract
The bacterium Porphyromonas gingivalis is a clinically significant agent in periodontitis, a disease for which there is no definitive cure. Several groups have attempted to kill this bacterium using low levels of light in the absence of a photosensitizer, with conflicting results. We hypothesize that it is not possible to kill P. gingivalis by targeting endogenous porphyrins for a photochemical reaction. We demonstrated that irradiation of P. gingivalis with 455 or 625 nm light emitting diodes did not induce a photochemical killing of the cultures. Controlled temperature experiments indicate that irradiation at either wavelength did not significantly impact the growth of P. gingivalis cultures, as compared to non-irradiated controls. Rather, the irradiation caused a temperature increase in the growth medium, which altered the growth of the cultures. These results indicate that heat-induced killing of P. gingivalis could be the mechanism behind successful irradiation experiments with this bacterium.
Original language | English (US) |
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Pages (from-to) | 63-69 |
Number of pages | 7 |
Journal | Journal of Photochemistry and Photobiology B: Biology |
Volume | 77 |
Issue number | 1-3 |
DOIs | |
State | Published - Dec 2 2004 |
Keywords
- Anaerobic bacterium
- Endogenous porphyrin
- Gram negative
- Heme pathway
- Oxygen
- Photosensitization
- Thermal response
- Thermally labile
ASJC Scopus subject areas
- Radiation
- Radiological and Ultrasound Technology
- Biophysics
- Radiology Nuclear Medicine and imaging