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Full-Text Articles in Physical Sciences and Mathematics
Martian Life Detection With Amino Acid Enantiomers, Ali Jamil, Gaosen Zhang, Henry J. Sun
Martian Life Detection With Amino Acid Enantiomers, Ali Jamil, Gaosen Zhang, Henry J. Sun
Undergraduate Research Opportunities Program (UROP)
The Viking mission showed that Martian soil can degrade a heterotrophic medium to carbon dioxide as if live microorganisms were present. The result is considered inconclusive, however, because abiotic oxidants, such as superoxides, may also exist on Mars and would explain the Viking result. One way to resolve this ambiguity is to repeat the Viking experiment with a isomerically pure medium. The consumption of one isomer, either D or L, would indicate biological activity. Indiscriminate destruction of both isomers would indicate abiotic redox processes. This idea was validated for glucose by REU research last summer (Sun et al. 2009). The …
Researching Nitrite Oxidation At High Temperatures, Dolores A. Huang, Jeremy A. Dodsworth, Brian P. Hedlund
Researching Nitrite Oxidation At High Temperatures, Dolores A. Huang, Jeremy A. Dodsworth, Brian P. Hedlund
Undergraduate Research Opportunities Program (UROP)
15N-nitrate (NO3 -) pool dilution experiments show that ammonia (NH3) is oxidized to nitrate in geothermal springs up to at least 85C; however, nitrite (NO2 -)- oxidizing microorganisms are only known to grow up to 66°C. We hypothesize that thermophilic microorganisms oxidize nitrite to nitrate at high temperatures. Alternatively, it is possible that nitrite is oxidized abiotically. We propose to test these hypotheses by setting up microbial enrichments designed to grow thermophilic nitrite oxidizing bacteria by varying incubation temperature (50, 65, 80°C), oxygen concentration (20% and 5%), and cultivation media. A negative control consisting of filtered spring water (0.1 μm) …