CHANGES IN POLYPEPTIDE DISTRIBUTION STIMULATED BY DIFFERENT LEVELS OF ELECTROMAGNETIC AND THERMAL-STRESS

The distribution patterns of proteins synthesized by Sciara salivary gland cells in response to weak low frequency electromagnetic (EM) fields strongly resemble those following ''heat shock'' (HS). With increasing stimulus intensity of 60 Hz EM fields from 0.8 to 800 mu T and HS temperatures from 25.5 to 45 degrees C, there is also a similar sequence of changes. Two of the features in the molecular weight distribution, the %mass in the 30 kDa and 70 kDa ranges, show a similar alternating zigzag pattern in plots of the %mass with increasing stimulus intensity. The small differences between the responses to EM and HS appear to be due to the effects of the elevated temperatures in HS. The biosynthetic response to both EM and HS, when the two stimuli are given simultaneously or sequentially, is indistinguishable from the response to a single stimulus and is not additive. The responding cellular apparatus appears to be the same for both stimuli and to go through the same sequence of changes with increasing energy, even though the energies of the two stimuli differ by many orders of magnitude.