Abstract
The addition of 0.5% glucose solutions to 12 different air-dried soils always resulted in increased electrical conductivity and water-soluble Ca and Mg in the soil solutions. The kinetics and magnitude of these changes for at least two and usually all three of these parameters over a 14-day period were clearly distinguishable from the changes in heat-sterilized controls or unsterilized controls without added glucose. In general, maximal values were achieved more rapidly under aerobic than anaerobic incubation. Some soils (less than half) also showed significant increases in water-soluble Na or K when compared with the controls. The 12 different soils studied represented four general soil groups: I, leached acid upland soils; II, saline alkaline soils; III, nonsaline neutral soils; and IV, high organic soils. Viable counts ranged from 104 to 107 per cm3 of air-dried soil. Glucose metabolism by the indigenous soil microbiota was always accompanied by a significant decrease in the pH of soil solutions, but not necessarily by an increase in the viable count. The feasibility of using electrical conductivity and water-soluble Ca and Mg measurements to detect metabolic activity, either alone or in conjunction with other life detection techniques, is discussed.
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Selected References
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- Merek E. L., Oyama V. I. Analysis of methods for growth detection in the search for extraterrestrial life. Appl Microbiol. 1968 May;16(5):724–731. doi: 10.1128/am.16.5.724-731.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ponnamperuma C., Klein H. P. The coming search for life on Mars. Q Rev Biol. 1970 Sep;45(3):235–258. doi: 10.1086/406590. [DOI] [PubMed] [Google Scholar]
- Radmer R., Kok B. A unified procedure for the detection of life on Mars. Science. 1971 Oct 15;174(4006):233–239. doi: 10.1126/science.174.4006.233. [DOI] [PubMed] [Google Scholar]