WALNUT CREEK, CA--Researchers have now characterized the unique lifestyle of a gutless worm that commutes through marine sediments powered by a community of symbiotic microbial specialists harbored just under its skin, obviating the need for digestive and excretory systems.
From a species of marine oligochaete worm isolated off of the coast of Elba, the Mediterranean island of Napoleon's exile, scientists from the U.S. Department of Energy's Joint Genome Institute (DOE JGI) have described this complex worm/microbe quid pro quo revealed by DNA sequencing and other diagnostic techniques. Their results are published in the September 17 edition of the journal Nature (http://www.nature.com/nature/journal/vaop/ncurrent/abs/nature05192.html).
The worm, Olavius algarvensis, has no mouth to take in food, but does not go hungry, thanks to the goodwill of its hardworking bacterial tenants. In the transaction, the worm shuttles the bacteria to optimal energy sources it encounters wending its way between the upper oxygen-rich and the lower oxygen-depleted coastal sediments. In exchange, fixed carbon, all required amino acids and vitamins are synthesized by the subcuticular communities of microbial symbionts, providing their host with ample nutrition.
On the other end of the digestive equation, such waste products as ammonium and urea, generated by the worm's metabolism, are taken up by these symbionts--not only aiding the host in the removal of these toxic waste products, but also conserving valuable nitrogen, further maintaining the microbial community.
"It's an excellent example of outsourcing energy and waste management, where this worm and the microbes living under its skin are enjoying a mutually beneficial relationship," said Eddy Rubin, DOE JGI Director. The work was conducted by postdoctoral fellow Tanja Woyke and colleagues from the Rubin lab at
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Contact: David Gilbert
gilbert21@llnl.gov
925-296-5643
DOE/Joint Genome Institute
18-Sep-2006