title: Resistance of the protozoan Colpoda maupasi to Martian conditions of atmospheric pressure and low partial pressure of oxygen.
abstract: Among the most important factors limiting the active life of animal organisms in Martian conditions are low atmospheric pressure and insignificant amounts of oxygen in the atmosphere (no more than 0.15% of the Earth's atmosphere). The experiments with aerobic protozoon C. maupasi have shown that in conditions of hermetically sealed chambers, for instance in 2.5 liter anaerostats, the protozoon can survive for a long time and reproduce in an atmosphere of air or nitrogen containing 1 or 0.0005% oxygen at a pressure from 15 mm Hg and higher. At the atmospheric pressure 10 mm Hg we observed a considerable decrease in the survival percentage and no reproduction. The exposure to 5 mm Hg resulted in a 100 per cent mortality of the protozoon. In a specially-constructed chamber "Photostat", in which current atmosphere pressure were automatically maintained during an experiment of many days, the reaction of the infusoria was somewhat different: they reproduced and existed not only at the pressure of 10-15 mm Hg, but also at 5 mm Hg, in an atmosphere of both air and nitrogen containing from 1 to 0.0005% O2. This indicates not only low-oxygen consumption of unicellular animals but also the capability of cells to extract some traces of this gas from the atmosphere. Low pressure and some traces of oxygen in the Martian atmosphere are not an impediment for the existence of some of the Earth's animals, such as the protozoon C. maupasi for example.
authors.affiliation: USSR.
authors.forename: L K
authors.initials: LK
authors.lastname: Lozina-Lozinsky
authors.forename: V N
authors.initials: VN
authors.lastname: Bychenkova
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001272:Atmosphere / Q000032:analysis; D001274:Atmospheric Pressure; D056890:Eukaryota / Q000254:growth & development*; D005118:Extraterrestrial Environment; D018535:Mars; D009584:Nitrogen / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*
chemical_list: D009584:Nitrogen; D010100:Oxygen