[Effect of shielding as a cause of UV-action spectra shift in mammalian cells]

UV absorption at different wavelengths from 250 to 313 nm was measured in various sites of single SPEV cells in monolayer during the stage of the best cell flattening. At the 260 nm, transmittancy of nuclear regions was less than 50%. The absorption by nucleolar regions was twice as much as by cytoplasmic ones. The influence of self-shielding on the action spectra shape was estimated. It has been shown that the well-known difference between the peaks of the action spectra for mammalian and bacteria cells killing may be the result of the cell self-shielding at short wavelengths but not the sequence of the difference in the active chromophore of these cells.