Natural Products as Drugs - Biotechnology and Your Health: Pharmaceutical Applications - page 28

environmentalists, because this process killed the slow-growing and
scarce yew tree. Researchers eventually succeeded in synthesizing
paclitaxel from a chemical precursor found in the needles of
another yew tree, Taxus baccata , which grows abundantly in Asia
and Europe. The needles could be harvested and the drug made in
a factory without sacrificing trees. Scientists have not yet succeeded
in producing paclitaxel from scratch in the lab or in producing the
drug or a precursor from plant cells grown in large vats.
THE DISCOVERY OF ANTIBIOTICS
Antibiotics have a long history, and represent another highly suc-
cessful application of conventional biotechnology. In China, Egypt,
and among some native South American tribes, molds were used to
treat rashes and severe skin infections, such as boils. The modern
antibiotic era began with British bacteriologist Alexander Fleming's
serendipitous discovery of penicillin in 1928, the first successful
result of a 50-year search for chemicals produced by one micro-
organism that were able to kill another organism, or at least stop
its growth (Figure 2.2). In the struggle to survive in competitive
conditions with limited food sources, molds , fungi , and bacteria
discharge antibiotic substances into the local environment. Many
antibiotics currently in use, including penicillin, were discovered by
observing the ability of a colony of mold or fungus to prevent the
growth of bacteria (Figure 2.3). Cephalosporin, the first of a series
of related and widely used antibiotics, was isolated in 1948 from a
fungus discovered from the sea near Sardinia, an island off the west
coast of Italy. The story is that the sample was taken from the sea
near the outlet from a sewage treatment plant!
Many medically useful antibiotics are first discovered by putting
bacteria in a culture dish with molds or fungi to see whether the mold
or fungus kills the bacteria or slows its growth. But finding dead
bacteria on a lab dish may not necessarily mean that a useful drug
is being produced. Today, most of the clinically useful antibiotics