Sunday, September 12, 2010

Cockroach Antibiotic

Drug-resistant bacterial infections have become a major problem of the current decade.  Increasingly powerful antibiotics are frequently variants of current drugs and bacteria can develop resistance to them within a few years.  So where do you look for a completely new antibiotic to attack them?  Why not try a cockroach brain?

LiveScience.com reports that researchers have found at least 9 compounds in the brain and nervous system of cockroaches and locusts which fight drug resistant strains of E. coli and Staphylococcus aureus.  Since cockroaches can carry over two dozen human pathogens, it was logical to look at why they weren't susceptible to them.  The article doesn't discuss how you dissect out a cockroach brain.  I would guess that first you hire this really tiny little neurosurgeon.
Why a cockroach?  Well for one thing, they are about the oldest creature that you can see moving with the naked eye. Fossils of cockroach-like creatures date between 354–295 million years ago and the species has survived and evolved through the last three mass extinctions.  The modern cockroach has existed since at least the early Cretaceous Period which wiped out the dinosaurs.
For a species to survive that long, you have to be one tough cookie.  You may recall the recent blog describing a woman stepping on a living cockroach and having a horsehair worm crawl out of it. Cockroaches live in areas where they are exposed to all the bacteria in animal waste and presumably have developed their own resistance to them.
For such an antique animal, their behavior can be relatively sophisticated.  They can leave a pheromone trail which other cockroaches can follow to food sources or swarming for shelter and mating  They also can teach us humans something about developing group dynamics, as described in Wikipedia.
"Research has shown that group-based decision-making is responsible for complex behavior such as resource allocation. In a study where 50 cockroaches were placed in a dish with three shelters with a capacity for 40 insects in each, the insects arranged themselves in two shelters with 25 insects in each, leaving the third shelter empty. When the capacity of the shelters was increased to more than 50 insects per shelter, all of the cockroaches arranged themselves in one shelter. Researchers found a balance between cooperation and competition exists in group decision-making behavior found in cockroaches. The models used in this research can also explain the group dynamics of other insects and animals."
It is said that cockroaches will inherit the earth long after humans are extinct.  Like many other insects, they can withstand ten times the dose of radiation which is lethal to humans.  Radiation is lethal to cells when they divide.  Unlike mammals whose cells are constantly dividing, a cockroach's cells divide all at once during their molting period.  A blast of radiation will kill some but doesn't affect the others who are between molts.
So, will cockroaches inherit the planet?  Well, they have a good chance.  They can live in a wide variety of climates, survive underwater for half an hour, remain active for a month without food and "survive on limited resources like the glue from the back of postage stamps."    They may run short of food as we convert to e-mail, but they probably won't get Staphylococcal meningitis.

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