Ultra-high vacuum and microorganisms.

Experimental study of the space environment effect on living organisms is one of the most important tasks of exobiology. However location of the living organisms under study outside space vehicles and sputniks is combined with technical difficulties. Therefore it is much more suitable to reproduce conditions found in space in laboratory and to study its effect on living cells. It was proved that low temperatures, even those approaching absolute zero do not kill microorganisms. The fact of microorganisms surviving radiation of some million roentgen suggests that they would not be killed by ionizing radiation in space. UV rays should be considered as the most active sterilizing agent. The ability of microorganisms to resist high vacuum is studied much worse. Under the action of high vacuum at 10(-8)-10(-9) mm Hg during 72 hours all studied seven species of spore-forming bacilli remained viable. As for nonsporeforming bacteria under conditions mentioned, cells of some species perished (correction of parished) completely while other species retained viable cells. Conidia of fungi and parts of mycelium of fungi which do not form conidia, sustained high vacuum well.