Geoscience Reference
In-Depth Information
Biological Warfare
Better a Spanish snail in the scissors
than four hundred eggs in your vegetables!
Nils Nyberg
Abstract Microorganisms produce a wealth of chemicals as they fight for space
in the soil. We use some of these as medicine, such as penicillin and streptomy-
cin, but also less well-known varieties such as cyclosporin, which revolutionised
transplant surgery. Resistance to antibiotics is a growing problem in humans, but
in South America there are fungi-cultivating ants which have been using antibiot-
ics for millions of years apparently without encountering such problems. There is
a lot to be learnt here. Many people see biological control as an environmentally
friendly way of dealing with pests—and sometimes it works, such as when the spi-
der mite is combated using predatory mites in tomato cultivation. At other times it
is catastrophic, as when cane toads were introduced to combat beetles in sugarcane
plantations in Australia. A special group of fungi makes short work of nematodes
which cause diseases in both plants and animals, and a great deal of research has
been conducted to get them to function as medicine or biological control agents. But
profound ecological insight is required to get such a construction to work.
The soil is a crowded place and at times organisms may engage in open warfare
as they jostle for space. Some microorganisms, for instance, use antibiotics to stop
other species from getting too close. Sometimes we can harness the attack mecha-
nisms of soil organisms for our own benefit.
How Soil Organisms Can Help Us
Most people have heard the story of how Alexander Fleming discovered penicil-
lin in the 1930s by accident when a mould spore settled in a forgotten Petri dish
containing yellow staphylococcus. Fleming noticed how the bacteria surrounding
the mould colony died. After his death, scientists succeeded in isolating the active
substance, penicillin, which has since been used to fight infections worldwide.
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