Genome of infectious bacterium decoded
Research teams based at Lawrence Livermore and Uppsala University
in Sweden have decoded the complete genomes of separate strains
of Francisella tularensis, a highly infectious human and animal
pathogen. Also participating were researchers at Porton Down
in the United Kingdom, the Swedish Defense Agency, the U.S. Centers
for Disease Control and Prevention, and the Walter Reed Army
Institute of Research.
the genome sequences of the two strains will help us identify
the genes, and their associated proteins, that cause
strain of F. tularensis to be more virulent than another,” says
Livermore biologist Emilio Garcia. Knowledge of the microbe’s
genomic sequence—the precise order of the nucleotide bases
in its DNA—can improve scientific understanding of its fundamental
physiology and metabolism. This knowledge also could help researchers
develop more effective vaccines and better methods for diagnosing
or rabbit fever, is a rare but serious disease normally spread
by insect bites and human contact with rabbits, prairie
dogs, and other small and medium-size animals. The disease can
be treated with antibiotics and is seldom fatal. However, it is
highly infectious—as few as 10 organisms entering the body
can induce a fever—and causes severe, long-lasting pneumonialike
symptoms and various glandular and intestinal disorders. F.
tularensis is also considered a potential bioterrorism agent.
Contact: Emilio Garcia (925) 422-8002 (email@example.com).
bursts expel common elements
20, 2004, issue of Astrophysical
Journal Letters, Jason Pruet, a
Livermore astrophysicist, and Rebecca Surman and Gail McLaughlin
of North Carolina
State University report on their discovery that gamma-ray bursts are important
sources of several common elements. Their findings are based on recent observations
indicating that each gamma-ray burst expels about half a solar mass of readily
visible radioactive nickel. After a few months, this radioactive nickel, which
is moving at 40,000 kilometers per second, decays to iron. Their modeling
calculations show that gamma-ray bursts also produce enormous quantities of such
everyday elements as zinc, titanium, calcium, and scandium.
Gamma-ray bursts are rare—only a small percentage of dying stars produce
them. But, says Pruet, these events may account for as much of some elements
as all other stellar explosions combined.
Contact: Jason Pruet (925) 422-5850 (firstname.lastname@example.org).
Guide star sheds light
on stellar origins
In a university–laboratory collaboration, a team of astrophysicists has
observed for the first time that distant larger stars formed in flattened accretion
disks just as the Sun was formed. Less massive stars, including the Sun, are
believed to be formed in a swirling spherical cloud that collapses into a disk.
Using the laser guide star adaptive-optics system created by Livermore scientists,
the astronomers observed a strongly polarized, biconical nebula 10 arcseconds
in diameter around the star LkHa 198 and a polarized jetlike feature in LkHa
198-IR. The star LkHa 233 featured a narrow, unpolarized dark lane similar to
an optically thick circumstellar disk.
The team included scientists from Lawrence Livermore, the University of California
(UC) at Berkeley, UC Santa Cruz, California Institute of Technology, the National
Science Foundation’s Center for Adaptive Optics, and UC’s Lick Observatory.
Results from this research were published in the February 27, 2004, issue of
Contact: Claire Max (925) 422-5442 (email@example.com).
Prototype containment vessel
Livermore scientists and engineers have successfully tested a prototype composite
containment vessel for explosive experiments. The half-scale prototype vessel,
about the size of a large medicine ball, contained an internal blast from an
8-kilogram (18-pound) soccer-ball–size sphere of C4 explosive in a test
at Livermore’s Site 300. The new vessel is designed to accommodate the
more stringent containment standards that are likely to be developed for future
experiments with explosives, especially those involving nuclear material.
aramid fibers, such as those used in bulletproof vests, make up the vessel’s
outer shell, which provides the primary structural resistance
against the blast forces. An aluminum liner underneath this shell provides
surface and doubles as the winding mandrel for the composite filaments. This
design is stronger than steel, and radiographic measurements can be taken through
the vessel wall—no ports are necessary.
work is part of a joint project with Los Alamos National
Laboratory to develop a full-size (2-meter-diameter) windowless firing vessel
that can completely contain a cased explosive with up to 0.04 metric ton (80
pounds) of TNT equivalent.
Contact: John Pastrnak (925) 422-8403 (firstname.lastname@example.org).