Аннотация:Survival of living organisms in constantly changing environmental conditions is possible due to universal hereditary strategies of adaptation to various types of stress, based on structural, biochemical and genetic rearrangements. One of the strategies implemented in bacterial cells is related to the protection of the nucleoid from unfavourable environmental conditions by binding of DNA to specific histone-like proteins, the main one being the protein Dps (DNA binding protein from starved cells), and condensation of DNA with DPS in nanocrystalline complex which was recently discovered in gram-negative bacteria. A series of diffraction experiments to study structural response to stress or stress-induced biocrystallization in bacteria E. coli, spore -forming bacteria Bacillus cereus, in cells and spores of mycelial fungus Umbelopsis ramanniana was performed for the first time. Zones of increased intensity at resolution 90 A and 44 A indicate an ordered organization (most likely nanocrystalline) of bacterial nucleoid in E. coli cells. For the starving bacteria Bacillus cereus peak at a resolution of 45 A, apparently, also associated with the presence of nanocrystalline complexes of DNA with histone-like proteins. The spores of the fungus Umbelopsis ramanniana BKM F-582, as well as the spores of Bacillus cereus create ordered sets of DNA molecules with DNA condensing acid - soluble proteins SASPs. Starving, dehydrated mycelial cells of the fungus Umbelopsis ramanniana, form ordered structures at resolutions of 27 A to 55A. The series of peaks reflects the formation of a number of orderly protein formations with continuously changing characteristic size of the interplanar spacings. This work was supported within frameworks of the state task for ICP RAS 0082-2014- 0001. State registration # AAAA-A17-117040610310-6.