ABSTRACT
The object of this work was to study the effect of vacuum on Endomyces magnusii, Serratia marcescens, Escherichia coli and Mycobacterium luteum. The zone of tolerance to the water activity was determined for the intact cells of E. magnusii and for the cells subjected to vacuum. Suspensions of the above cells were studied by UV spectroscopy with the aim of detecting changes in the permeability of cell membrane after the action of vacuum.
Subject(s)
Ascomycota/physiology , Atmospheric Pressure , Escherichia coli/physiology , Mycobacterium/physiology , Saccharomycetales/physiology , Serratia marcescens/physiology , Vacuum , Carbon Dioxide/metabolism , Cell Membrane Permeability , Escherichia coli/analysis , Mycobacterium/analysis , Saccharomycetales/analysis , Serratia marcescens/analysis , Spectrophotometry, UltravioletABSTRACT
The biology of xerophytic microorganisms surviving and growing under conditions imitating Martian ones was studied, as well as the zone of tolerance of several microorganisms towards the activity of water. The xerophytic nature of microorganisms is suggested to be evaluated by means of quantitative determination, using gas chromatography, of carbon dioxide which is evolved when microorganisms are cultivated on media with different values of aw.
Subject(s)
Bacterial Physiological Phenomena , Fungi/physiology , Aspergillus/physiology , Bacillus/physiology , Bacillus megaterium/physiology , Culture Media , Desert Climate , Extraterrestrial Environment , Mycobacteriaceae/physiology , Spirillum/physiologyABSTRACT
The main factor limiting growth of terrestrial organisms under Martian conditions is the low humidity; therefore the biology of xerophytic micro-organisms has been studied. We found earlier that Bacillus megaterium var. halotolerant and Mycococcus ruber could survive and grow under Martian conditions. In this work, we studied the zone of tolerance of these and some other micro-organisms towards various levels of water activity, and the toxicity of substances which were used to control this activity. A technique for quantitative evaluation of the xerophytic nature of micro-organisms is proposed. The technique is based on quantitative evaluation by gas chromatography of carbon dioxide evolved in the course of growth of micro-organisms on media with different values of water activity.
