A new bacterial genome sequenced by a team led by the Department
of Energy’s Oak Ridge National Laboratory could help researchers
solve a mystery as to how microorganisms produce a highly toxic
form of mercury. Image right: A bacterium called Desulfovibrio
desulfuricans strain ND132 can transform elemental mercury into
methylmercury, a human neurotoxin. (Oak Ridge National
Laboratory) Methylmercury, a potent human and animal neurotoxin,
appears in the environment when certain naturally occurring
bacteria transform inorganic mercury into its more toxic cousin.
Few bacterial species are capable of this conversion, and
exactly how the transformation takes place has been a matter of
debate for decades. Methylmercury sticks to proteins in living
organisms and accumulates in the food chain. “What is not known
are the genes or the proteins that allow these bacteria to
mediate the transformation,” said ORNL’s Steven Brown, who led a
research team to sequence the genome of a bacterium in the
Desulfovibrio genus that i