old star-treky like me stands in awe when I ponder the world of
microbiology. The humanbody has some 10**13 (i.e., 10 million times
1 million) cells, a number pretty hard to comprehend. Within our
bodies, however, are 10 times as many bacteria. Many of these bacteria
are those we have evolved alongside, and some provide benefits to
our bodily functions (if you don't buy this, just take a good regimen
of potent antibiotic, and see what happens to your digestive track).
Although the mammalian gut is packed with microorganisms, inflammatory
responses are rare, again because we evolved in tandem with many
of these microorganisms.
on and everywhere around us, too small to see is a separate universe,
that we explore with microscope and DNA sequencers rather than warp
engines. Bacteria, fungi, viruses, protozoa are as abundant as they
are ubiquitous on earth, and on balance, life as we know it is highly
dependent on their functions. For example they produce some 1/2
of the Earth's atmosphere, and form the foundation of the critical
food chain. Symbiosis with higher animals abounds.
bodies contain 10**14 bacteria, many species, and all of these undergo
at rapid rate, natural selection. Their relatively simple genomes
enable fast replication, and thus fast adaptation to environmental
threats, such as the threat of man-made antibiotics. In fact, these
microscopic organisms dating to almost 4 billion years ago, prepared
the early genomic templates that led to all other life on Earth
- perhaps they are, the final frontier.
is hard to be interested in life and evolution, and ignore the little
bacteria. I call your attention to a special issue of Science Magazine,
and Evolution of Infection" dated May 11, 2001 (most libraries
have this prestigious journal). Science has also compiled a web
supplement and provides links
to related web information.