The finding of a viable bacteria spore trapped within an ancient rock crystal, has caused scientists to question whether some bacteria are immortal. In a letter published in the October 2000 issue of the journal _Nature_, scientists announced the finding of a bacteria spore within a brine inclusion in a salt crystal which was dated at 250 million years old or older. In an accompanying "News and Views" commentary entitled, "Microbiology: A case of bacterial immortality?" author R John Parks of the University of Bristol asked, "If bacteria can survive for this length of time, why should they die at all?"
Spores are resistant structures formed by bacteria that are known to survive for long periods. Although researchers have found and cultured live spores from ancient rocks and coal, the possibility of contamination of the sample with bacteria from an outside source has rendered these results questionable. In the 1990s, scientists found bacteria inside a bee preserved in amber that was between 25 and 40 million years old. The surface of the amber was sterilized prior to removing the spores to eliminate the possibility of outside contamination. The spores were subsequently cultured and found to be viable.
In this latest finding, the bacteria push back the age of the longest-lived organism on earth to ten times that of the previous discovery. Researcher Russell H Vreeland and colleagues utilized stringent sterilization procedures on the surface of the sample and on the drill apparatus, and drilled into the fluid inclusion. The bacteria (of the genus Bacillus) was inoculated into a growth medium, where it then grew. Because of the extent of sterilization procedures used, Vreeland estimates the chance of contamination as one in one billion.
In the _Nature_ commentary,
replication of these results is urged to ensure their full acceptance.
However, the author admits that the implications of the finding are profound.
The discovery of a 250 million year old life form has prompted the speculation
that immortality could be possible for at least one species. It remains
for researchers to discover what it is that enables them to survive.