UpDate - Vol. 15, No. 31, Page 9
May 9, 1996
Hot vent worms may provide novel biocatalysts

     Lurking around the steaming chimneys that form in the deep sea
hydrothermal vents off the west coast of Mexico are small tube worms
that may be the most heat-tolerant species on Earth.
     Craig Cary, University marine biologist, is collecting and
characterizing these 4-inch-long Pompeii worms, whose very tolerance
to hot and cold extremes may make them valuable to the chemical and
pharmaceutical industries.
     "What makes the worm exciting," Cary says, "is that it carries a
unique bacterial community on its back, and their symbiotic
relationship may be what makes it possible for the worm to live in
this very extreme environment."
     Hot fluids laden with hydrogen sulfide and heavy metals
constantly move through the tubes in which these worms live. In
addition, the Pompeii worm lives within the broadest temperature range
(from 10 C to 80 C) of any organism on the planet, Cary says.
     On the Celsius temperature scale, 0 C represents the freezing
point of water and 100 C is the boiling point.
     Cary looks at molecular aspects of unique bacterial symbioses
with marine invertebrates. He collects the Pompeii worm from
hydrothermal vents at several locations along the East Pacific Rise-an
area of the sea floor where crustal plates are moving apart and new
crusts are forming.
     Over the last 10 years, Cary, a molecular physiologist, has made
eight trips to these sites.
     His most recent cruise last November was to the Axial Summit
Caldrea, located nine degrees north of the equator on the East Pacific
Rise and the site of a recent volcanic eruption and lava flow. During
this cruise, he made two dives in the research submersible, DSV Alvin,
to a location about 1-1/2 miles below the ocean surface.
     Although the temperature at the top of the hydrothermal vent
chimneys may reach more than 400 C, the Pompeii worms live along the
chimney sides where the flow of water is more diffuse. Using a
sensitive temperature recorder, Cary has measured the water flowing
through the tubes of the Pompeii worm at 80 C while the water outside
is a chilly 2 C.
     Although French researchers originally described this worm in the
early 1980s, Cary says an international collaborative effort is now
being made to examine in more depth the bacteria that cover the worm
host with hair-like strands.
     Cary's laboratory is studying the metabolic links between the
worm and these bacteria, which he suspects have allowed the obscure
organism to adapt to live in such an incredibly harsh environment on
the sea floor.
     "If the bacteria on the Pompeii worm utilize eurythermal enzymes
[enzymes that operate efficiently over a wide range of temperatures],
this research will be appealing to industry, which wants more
aggressive enzymes or biocatalysts that work over a broader
temperature span," Cary says. "These protein-based catalysts also are
sought by other industries where chemical processes work better at
higher temperatures, such as pharmaceutical production, agriculture,
food and beverage, pulp and paper and textiles."
     Cary collaborates in this NSF-
     funded research project with a former graduate school colleague,
Jeff Stein of Recombinant Biocatalysis Inc. Based in La Jolla and
Philadelphia, the newly formed company (RBI) is dedicated to the
discovery and development of new protein-based catalysts. Cary says
their two linked proposals demonstrate how basic science and industry
can benefit from collaboration.
     "The analytical power and enthusiasm of RBI takes us years ahead
in our studies," he says.
     One goal of RBI is to collect thermally stable biocatalysts from
such hostile environments as volcanoes, hot springs and hydrothermal
vents, Cary says. "The general idea is to collect the bacteria,
stabilize the nucleic acids (DNA and RNA) and then head back home to
create libraries of pieces of this genetic material. RBI is now
screening the Pompeii worm's DNA for novel enzymes that could break
down fats, proteins, DNA and even wood products more efficiently."
                                                        -Cornelia Weil