Chitwood examines the effects of an inhibitor of sterol metabolism on the
nematode Caenorhabditis elegans. Inhibiting the sterol metabolism of
nematodes may be one way of turning their biology against them. Click the
image for more information about it.
story to find out more.
A Search for Nematodes' Biological Soft
Spots By Luis
August 10, 2004
Service scientists are seeking ways to use a nematode's own biology against
Searching for vulnerabilities,
Laboratory researchers in Beltsville, Md., are probing the genes and
proteins, susceptibility to toxins--and even the cholesterol--of the
microscopic worms that cause more than $10 billion in crop losses each year
The focus is on basic processes such as locomotion, egg hatch,
growth and development and molecules that help maintain cell health and
Physiologist Edward Masler, molecular biologist Andrea Skantar
and plant pathologists Lynn Carta and Susan Meyer are exploring whether
heat-shock proteins (HSPs) represent a chink in the worms' armor. As part of
these studies, Skantar was the first to report HSP-90 in soybean cyst
nematodes. This protein regulates other proteins that control normal cell
development and metabolism, and it appears to govern adaptation to
environmental extremes in many organisms.
Skantar, Carta and Meyer inhibited HSP-90 in nematodes by
exposing the worms' eggs to geldanamycin, a bacteria-produced compound. They
now plan to examine these bacteria as biocontrol agents against nematodes.
Masler's work led to the discovery in cyst nematodes of HSP-70,
which helps them respond to stress, and to the first description of the actin
gene in the worms. Actin is a protein active in muscular contraction, cellular
movement and cell shape maintenance. The researchers seek to design
actin-control agents specific to nematodes but harmless to other organisms.
Carta evaluated the nematode-killing properties of toxins found
in Bacillus thuringiensis, a common bacterium that poses no threat to
humans but targets nematodes' gut. She found four toxins that damaged at least
two nematode species.
Meanwhile, ARS zoologist David Chitwood of the Nematology
Laboratory and researchers from
Yonsei University in
Seoul, South Korea, seek to learn exactly how disruption of sterol metabolism
actually kills nematodes. Sterols are chemical compounds found in cells. The
most common of these is cholesterol.
more about this research in the August issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.