Abstract

One of the persistent problems encountered in performing experiments with biological organisms in the ultraviolet (UV) region of the spectrum, is the availability of radiation sources with sufficient energy to elicit the desired response in a reasonable period of time. Hence, a large portion of UV photobiology has been conducted at wavelengths between 220 nm and 300 nm (1). Here certain important cellular chromophores, such as the genetic material DNA, absorb heavily and can be altered with the use of simple sources such as fluorescent lamps (eg. 254 nm "germicidal" lamps) or by more intense sources fractionated into monochromatic wavelengths (eg. mercury-xenon lamps and tandem grating monochromators). It is not surprising that this limited λ region is the most throughly understood area of UV cellular biology. Progress into the longer UV (300 nm to 400 nm) and the shorter UV (wavelengths less than 200 nm) regions has been hindered by lack of sources with sufficient energy.

© 1988 Optical Society of America