Lewis Thomas[1] was an award winning author and physician who had a way of explaining complex science in simple ways. In his essay, “Seven Wonders[2],” Lewis relates how he was once asked for his list of contemporary “Wonders of the World.” He is careful to say that he thinks it would be impossible to create a new list of the seven wonders of the world before giving a qualified list of naturally occurring wonders.
The “second” of his list (if you read the
entire essay[3]
you will understand why I put “second” in quotations) is a particular species
of bacteria which thrives at extremely high temperatures. Prior to their
discovery in the 1980s, many would have suggested that life as we knew it would
not be possible in the severe environment of deep sea vents where temperatures
exceed 250 degrees centigrade. Yet, these bacteria were found to be living and
contributing to the ecosystem in just such a place. As Thomas says, it was
thought that “Proteins and DNA would fall apart, enzymes would melt away,
anything alive would die instantaneously.” On this basis, “the possibility of
life on Venus . . .” and many other places was long ago ruled out.
Then came the discovery by B. J. A. Baross
and J. W. Deming “of thriving colonies of bacteria in water fished directly
from these deep-sea vents. . . . [that], when brought to the surface, encased
in titanium syringes and sealed in pressurized chambers heated to 250 degrees
centigrade, the bacteria not only survived” but reproduced themselves
enthusiastically. They [could] be killed only by “chilling them down in boiling
water. And yet they look just like ordinary bacteria. Under the electron
microscope they have the same essential structure—cell walls, ribosomes, and
all.”
I was later to learn of the great value of
these bacteria in the work I would do in the Molecular Diagnostic Lab at the
Alberta Children’s Hospital in Calgary. After this discovery by Baross and
Deming, other researchers went on to isolate particular strains of bacteria
from thermal vents. One species, Thermus aquaticus
(abbreviated Taq), contained a DNA polymerase (an enzyme which makes more copies
of a strand of DNA) that could be isolated and used in certain biochemical
reactions to amplify regions of DNA. By the time I joined the lab in 1990, it
was possible to use Taq DNA Polymerase for routine scientific investigation and
molecular genetic testing of clinical disorders. The use of PCR (Polymerase
Chain Reaction) greatly accelerated laboratory practices and led to the rapid
development of clinical testing for molecular DNA mutations. I would echo Lewis
Thomas in his recognition of these bacteria as one of the great wonders of the
world.
[1] “Lewis Thomas,” Wikipedia, https://en.wikipedia.org/wiki/Lewis_Thomas,
accessed 2016-09-12.
[2] Late Night Thoughts on
Listening to Mahler’s Ninth; Lewis Thomas, Viking Penguin, a division of
Penguin Group (USA) Inc., 1983.
