[Xerophytic microorganisms multiplying under conditions close to Martian ones]. / O kserofitnykh mikroorganizmakh, razmnozhaiushchikhsia v usloviiakh, blizikh k marsianskim.

The xerophytic cultures Bacillus megaterium and Mycococcus ruber can grow in the imitated Martian conditions. Therefore, they are resistant to the extreme factors of the environment: the composition of atmosphere, low pressure, the maximum hygroscopicity of a substrate, periodic freezing-thawing.

[Physiology of xerophytic microorganisms that grow under very dry conditions]. / Fiziologiia kserofitynykh mikroorganizmov, rastushchikh v ochen' sukhikh usloviiakh.

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.

Physiology of xerophytic micro-organisms growing under Martian conditions.

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.