X-Message-Number: 20700 From: "Ben Best" <> Subject: Scientists bring 2,800 year old frozen bacteria to life Date: 23 Dec 2002 15:54:42 -0800 Bill Faloon asked me to post this to CryoNet -- Ben Best Life Extension Weekly Update Exclusive Scientists bring 2,800 year old frozen bacteria to life In an article published in the Proceedings of the National Academy of Sciences online, a team of scientists reported reviving frozen microbes that are at least 2,800 years old found in an ice-sealed lake in Antarctica. Coauthor John C Priscu, of Montana State University stated, "These life forms may possess novel ice-active substances such as antifreezes and ice nucleation inhibitors that allow the organisms to survive the freeze-thaw cycles and come back to life when exposed to liquid water. Importantly, the cold temperatures preserve DNA extremely well making them perfect 'ice museums' for the study of ancient DNA." The researchers took samples from the frozen lake and thawed them to approximately 4 degrees Celsius. The bacteria were administered radioactive-labeled carbon dioxide and thymidine, which are involved in photosynthesis and DNA formation, respectively. After incubation with the tracers, the amount of radioactivity incorporated into the cell bodies was determined. This process demonstrated the microbes' viability and allowed their potential growth rates to be assessed. Dr Priscu told Life Extension Weekly Update, "Results from our experiments told us that the microbes can resume active metabolism once they 'see' liquid water. There is always the possibility that the cells may have been metabolizing slowly in the 'solid ice', something we did not test for. It is know that for purely physical reasons, liquid water exists between the boundaries of ice crystals and between the ice-sediment boundaries. My laboratory is actively examining the possibility of metabolism occurring at these interfaces in 'solid ice', but we have yet to show it unequivocally. Given what we have learned over the past 10 years about life in icy environments, I strongly believe that microbes do metabolize in solid ice-we just have to prove it! It will be a major scientific breakthrough if and when we do show that life does actively grow in solid ice. " He added, "Several of the microbes we have isolated so far appear to produce some type of ice active substance (IAS) that inhibits ice nucleation in their membranes. Some of these IAS's resemble dimethyl sulfoxide (DMSO), which was used routinely by athletes as a liniment for joint pain. These IAS's allow the cells to live through repeated freeze-thaw cycles without membrane damage. Try freezing and thawing your finger several times in your freezer and you will see that humans do not have this capability (tissue in your finger will die and the finger will self amputate). So, these secondary metabolic products allow the microbes to survive extreme cold and may someday provide humans with a natural product to help maintain cell integrity under extremely cold conditions." Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=20700