Morphological aspects of adaptation of the alkalophilic ba cteria Bacillus aequororis to high salinity and alkalinity of the medium

AFM-images were obtained and the morphometric parameters of cells of the facultative alkalophile Bacillus aequororis 5-DB and neutrophilic Bacillus subtilis ATCC 6633 were calculated after incubation in an alkaline medium with a high concentration of sodium chloride. It was shown that adaptation of B. aequororis 5-DB is not accompanied by significant changes in morphometric parameters, while the volume of cells slightly (by 1–1.5 times) decreases and their surface roughness increases. Neutrophilic bacillus, on the contrary, reacts to an increase in salt concentration and pH (50 g/l, pH 11) by significant changes in the cell: the cell volume decreases 2–3 times, and with daily adaptation to 50 g/l salt with pH 8 increases by 2.4 times due to the increase in cell length. Cells of an alkalophilic bacillus, in contrast to those of a neutrophilic bacillus, do not undergo significant changes in morphology with a high mineralization of the environment, both under direct exposure and after daily adaptation.