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Project Progress

Biochemistry of psychrophilic organism (dm)

Our objective is to study the diversity and properties of psychrophilic (cold-loving) microorganisms that can serve as models for the possible origin, evolution, and survival of psychrophiles from other cold, non-terrestrial sources. Our isolation and examination of bacteria belonging to new species and genera will shed light on the potential diversity of life elsewhere and provide clues to avenues for their cultivation.

Our work includes the isolation of numerous psychrophiles and the cloning of genes encoding glycosyl hydrolase genes. One isolate of particular interest was obtained from a hypersaline pond in Antarctica. We have shown that the isolate is a member of the Planococcus genus and that it is both psychrophilic and halotolerant (grows at low temperatures and high salt). Additional isolates from Antarctic samples have physiological traits and 16S rRNA gene sequences that differ from those found for other bacteria and may represent organisms belonging to a new genus.

In addition, we have developed procedures for obtaining and examining possible chemoautotrophic psychrophilic anaerobes from a Greenland Ice Core. A first step was the development of aseptic techniques for obtaining portions of the ice core as inocula without contaminating the sample. Samples from the center of the ice core were inoculated into a basal autotrophic medium and incubated at temperatures from 0°C to 15°C. We have demonstrated reproducible turbidity of cultures following repeated dilutions into new anaerobic media and incubation at 0°C over the course of several months. Microscopic examination demonstrates that there are several cell shapes and sizes in the mixed population. We are in the process of developing procedures for isolating the specific organisms in these cultures. In addition, we have attempted numerous cell lysis procedures in order to obtain sufficient DNA to allow amplification and cloning of the 16S rRNA genes.