Two Harvard Biologists Find Animal With Bacteria-Free Gut
Two Harvard biologists have found a genus of marine animals which has no bacteria in its digestive tract.
Paul J. Boyle, a graduate student in the Faculty, and Ralph Mitchell, professor of Applied Micro-Biology, discovered the phenomenon in Mitchell's laboratory at the Harvard Laboratory of Microbiological Ecology.
Boyle said he knows of no other animals that have a bacteria-free gut as a normal condition.
Boyle and Mitchell thought they had made a mistake when they originally discovered the phenomenon last summer. They were convinced all animals have micro-organisms in their digestive tracts, Boyle said.
"Essentially what we know is that the animal ingests bacteria and has no bacteria in its gut, so it must have a system for killing bacteria", Boyle added.
The animals are small marine wood-borer isopod crustaceans called Limnoria spp. There is one species of terrestial wood-borer crustaceans which also has a bacteria-free digestive tract.
The animals, sometimes called gribbles, produce a chemical that kills bacteria more powerfully than any other animal-made substance. They use the chemical to destroy all the microorganisms in the wood they eat.
The animals cause a fair amount of damage to wood in coastal zones, Boyle said.
"If we understand how the animal keeps its gut bacteria-free we may be able to interrupt that system and make the animal sick," he said, adding, "It might give us the ability to control its wood-boring activities."
They are studying the interactions between micro-organisms and marine invertebrates in order to find non-toxic means to control marine organisms which damage boats and docks, Boyle said.
The animal may have important implications for the Medical area because researchers need animals with bacteria-free guts in order to study colonization of digestive tracts by micro-organisms.
Mitchell and Boyle submitted a paper to the journal "Science," which will be published in June.