Microbes that help a gutless worm to eat and to process waste have developed unusual metabolic pathways to meet their own needs.

The worm Olavius algarvensis — found in marine sea-grass beds off the coast of the Italian island of Elba — harbours five species of bacteria in its body wall. Manuel Kleiner of the Max Planck Institute for Marine Microbiology in Bremen, Germany, and his colleagues identified and analysed 2,819 proteins and 97 metabolites produced by the worm or its associated bacteria. On the basis of their analyses, the authors propose that the bacteria generate energy for themselves using carbon monoxide and hydrogen from the surrounding sediment, and produce proteins that allow them to recycle waste products from the worm.

Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1121198109 (2012)