Interference image analysis of heat-shocked HeLa cells

HeLa cells were studied with the interference microscope 1 h after heat shock at temperatures of 40 degrees C and 43 degrees C and also under conditions of recovery from the shock. The aim was to investigate changes in patterns of cellular dry mass distribution with the heat shock, based on variation of interference colours in interphase cells. A change in concentration and distribution of a partly high-salt-resistant material in the nuclear and perinuclear regions of the cells was found to be induced by the heat shock at 43 degrees C, a situation which reverted to control under recovery conditions. A similar interference image response was obtained for the heat shock assay at 40 degrees C, but it was detected only during the 4 h recovery period, suggesting that it could have been elicited later. The material induced by the heat shock and visualized by the analysis of interference images is assumed to be a part of the nuclear matrix-intermediate filament cell fraction.