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Abstract:
The effect of repeated illumination by ultraviolet or visible light on slide cultures of Trichophyton ajelloi and Microporum cookei was studied. Under UV light, germination was inhibited, spores were damaged and destroyed, growth was suppressed and the hyphae were killed. Inhibition was dependent on exposure time and wavelength. Lethal doses for the far UV range were as high as 1 300-1 700 mW sec/cm2 for T. ajelloi and 2 300 mW sec/cm2 for M. cookei. The same effect was caused by the complete UV region but the far UV range was most effective. One exposure, however long, was not sufficient to kill the inoculum but this was effected by smaller doses when repeated 4 times at daily intervals. Under visible light, germination of the spores and growth of the young hyphae were inhibited. Depending on the exposure time and wavelength used, inhibition of 8 to 76% of controls grown in darkness were noted. The inhibition degree was increased up to lethality when the mycelium was sensitized by means of eosin. The coefficient of variation increased regularly up to very high values following exposures to sublethal doses of light...
Insights
Ultraviolet (UV) and visible light inhibit fungal growth, damaging spores and hyphae of Trichophyton ajelloi and Microporum cookei. Repeated light exposure, especially UV, proved more effective in killing fungal cultures than single doses.
Area of Science:
- Photobiology
- Mycology
- Antimicrobial Studies
Background:
- Fungal infections pose significant health challenges.
- Understanding the effects of light on fungi is crucial for developing novel control strategies.
Purpose of the Study:
- To investigate the impact of ultraviolet (UV) and visible light on the growth and survival of Trichophyton ajelloi and Microporum cookei.
- To determine the influence of exposure time, wavelength, and light repetition on fungal inhibition.
Main Methods:
- Slide cultures of T. ajelloi and M. cookei were subjected to controlled exposures of UV and visible light.
- Germination, spore viability, and hyphal growth were assessed.
- Experiments included varying exposure durations, wavelengths, and repeated light applications.
- Visible light studies involved eosin sensitization to assess enhanced inhibition.
Main Results:
- UV light significantly inhibited germination, damaged spores, suppressed growth, and killed hyphae.
- Inhibition by UV light was dependent on exposure time and wavelength, with the far-UV range being most effective.
- Repeated UV exposures were more lethal than single prolonged exposures.
- Visible light also inhibited spore germination and hyphal growth, with inhibition ranging from 8% to 76% compared to controls.
- Eosin sensitization enhanced the lethality of visible light.
Conclusions:
- Both UV and visible light exhibit antimicrobial properties against T. ajelloi and M. cookei.
- UV light, particularly the far-UV spectrum, is a potent agent for fungal inactivation.
- Repeated light exposure protocols can enhance fungicidal efficacy.
- Visible light's inhibitory effects can be potentiated, suggesting potential applications in combination therapies.