Group Title: Agricultural research (Washington, D.C.)
Title: Agricultural research
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Title: Agricultural research
Uniform Title: Agricultural research (Washington, D.C.)
Physical Description: v. : ill. ; 25-28 cm.
Language: English
Creator: United States -- Science and Education Administration
United States -- Agricultural Research Administration
United States -- Agricultural Research Service
Publisher: Science and Education Administration, U.S. Dept. of Agriculture :
Science and Education Administration, U.S. Dept. of Agriculture :
Supt. of Docs., U.S. G.P.O., distributor
Place of Publication: Washington D.C
Publication Date: March 1998
Frequency: monthly[1989-]
bimonthly[ former jan./feb.-may/june 1953]
monthly[ former july 1953-198]
Subject: Agriculture -- Periodicals   ( lcsh )
Agriculture -- Research -- Periodicals   ( lcsh )
Agriculture -- Periodicals -- United States   ( lcsh )
Agriculture -- Research -- Periodicals -- United States   ( lcsh )
Genre: federal government publication   ( marcgt )
periodical   ( marcgt )
Statement of Responsibility: U.S. Department of Agriculture.
Dates or Sequential Designation: Began with vol. 1, no. 1 (Jan. 1953).
Issuing Body: Vols. for Jan./Feb.-Nov. 1953 issued by: Agricultural Research Administration; Dec. 1953-<Sept. 1976> by: Agricultural Research Service; <June 1979>-June 1981 by: the Science and Education Administration; July 1981- by: the Agricultural Research Service.
General Note: Description based on: Vol. 27, no. 7 (Jan. 1979).
General Note: Latest issue consulted: Vol. 46, no. 8 (Aug. 1998).
 Record Information
Bibliographic ID: UF00074949
Volume ID: VID00015
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - ABP6986
oclc - 01478561
alephbibnum - 000271150
lccn - agr53000137
issn - 0002-161X

Full Text


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Inventions Along-
From Lab to
Typically, inventions progress from
a concept to working model, then ad-
vance through proof-of-concept, and
finally are ready for commercial im-
plementation. This process can be dif-
ficult for even the most promising and
potentially beneficial new ideas. Many
good ideas flounder in the step be-
tween a working laboratory model and
the proof-of-concept stage.
Government labs have historically
developed new technologies only to a
point of readiness for transfer to de-
velopers, while the private sector has
preferred to commercialize only well-
developed ideas with known risk.
Technologies caught somewhere be-
tween are said to be stranded in a sort
of Death Valley that represents a con-
fidence or investment gap.
This gap occurs when the invest-
ment required to complete develop-
ment of a new technology may be
beyond the research mission of the
government laboratory but too early
in the commercialization process for
the private sector to see it as an
acceptable business risk.
However, in the 1980s, the U.S.
Congress began to provide tools to
help government laboratories form
partnerships with the private sector to
bridge this confidence gap. Through
partnering, promising technologies
can receive both a research push from
the government lab and a commercial
pull from the private-sector partner.
Agricultural Research Service lab-
oratories have a long history of tech-
nology development with industry.
But spanning Death Valley has been
all too real a problem for the agency.
So governmentwide technology trans-
fer tools-such as cooperative re-
search and development agreements

and exclusive patent licenses-have
been important bridges.
The cover story in this issue high-
lights the 10th anniversary of one of
ARS' efforts to bridge the gap be-
tween fundamental research and suc-
cessful commercial application.
The Biotechnology Research and
Development Corp. (BRDC) brings
publicly funded basic science together
with industry in a way that maximizes
the chance for successful commercial-
ization of the research results. It was
created to leverage both public and
private resources by supporting fun-
damental research projects with com-
mercial potential identified by
BRDC's member companies.
With early industrial interest and
investment, Death Valley is growing
narrower and shallower and easier to
bridge. BRDC has served its role
well, with several important succes-
ses, and it is, we believe, on the verge
of reaping substantial further succes-
ses from early investments. It has
indeed been a life-sustaining bridge
for numerous young and vulnerable
The U.S. Department of Agricul-
ture has other innovative bridges, in-
cluding the Alternative Agricultural
Research and Commercialization
Corporation (AARC) and the Small
Business Innovation Research (SBIR)
Grant Program.
The AARC is USDA's own ven-
ture capital fund for investment
through loans and equity participation
in companies that are well positioned
to turn environmentally sound tech-
nologies into successful commercial
products. The SBIR program provides
critical research funding to small
companies in the early phases of com-
mercialization of new technologies
that are often derived from public re-
search facilities.
Both USDA initiatives have served
as effective bridges over the laborato-
ry-to-marketplace gap. In fact, several

private companies have already made
good use of these bridges to help de-
velop ARS inventions into successful
Pilot plant facilities in ARS utiliza-
tion centers provide another way for
our scientists and our industrial part-
ners to demonstrate proof-of-concept or
marketability of new ARS discoveries.
To build more bridges, ARS Office
of Technology Transfer and the Na-
tional Program Staff have been estab-
lishing cooperative working arrange-
ments with state economic develop-
ment programs and trade associations
to bring in additional resources to
speed the commercialization of ARS
inventions by our industrial partners.
With these bridges and other tech-
nology transfer tools now available,
we are well positioned to work with
industry to solve agricultural problems
of regional or national significance.
Companies with specific needs can
use various technology transfer tools
to plug into the ARS technology pipe-
line at any of three basic entry points
in the research continuum: cooperative
research early in the conception/dis-
covery of a new technology; during an
emerging-invention phase when intel-
lectual property rights may be gained
through close cooperation and devel-
opment; or via practical application of
existing inventions through patent li-
censing and commercial development.
Together with funding opportunities
or other resources from BRDC,
AARC, or the SBIR program at any of
these stages, Death Valley can be
crossed and successful real-world
solutions to important agricultural
problems achieved, ensuring a suc-
cessful return on the nation's
investment in public research.

Peter B. Johnsen, Director, and
C. Andrew Watkins, Technology
Development Manager, at the
National Center for Agricultural
Utilization Research, Peoria, IL

Agricultural Research/March 1998

March 1998
Vol. 46, No. 3
ISSN 0002-161X

Agricultural Research is published monthly by
the Agricultural Research Service, U.S.
Department of Agriculture, Washington, DC
The Secretary of Agriculture has determined
that this periodical is necessary in the transac-
tion of public business required by law.
Dan Glickman, Secretary
U.S. Department of Agriculture
I. Miley Gonzalez, Under Secretary
Research, Education, and Economics
Floyd P. Horn, Administrator
Agricultural Research Service
Ruth Coy, Acting Director
Information Staff
Editor: Lloyd McLaughlin (301) 344-2514
Assoc. Editor: Linda McElreath (301) 344-2536
Art Director: William Johnson (301) 344-2561
Acting Photo Ed.: Anita Daniels (301) 344-2956
Staff Photographer: Scott Bauer (301) 344-2957
Information in this magazine is public property
and may be reprinted without permission. Non-
copyrighted photos are available to mass media
in color transparencies. Order by photo number
and date of magazine issue.
Subscription requests should be placed with
New Orders, Superintendent of Documents,
P.O. Box 371954, Pittsburgh, PA 15250-7954.
See back cover for order form.
Complimentary 1-year subscriptions are
available to public libraries, schools, employees
of the U.S. Department of Agriculture, and the
news media. Send requests or comments to:
Editor, Agricultural Research Magazine, Room
408, 6303 Ivy Lane, Greenbelt, MD 20770. E-
This magazine may report research involving
pesticides. It does not contain recommendations
for their use, nor does it imply that uses dis-
cussed herein have been registered. All uses of
pesticides must be registered by appropriate
state and/or federal agencies before they can be
Reference to any commercial product or service
is made with the understanding that no discrimi-
nation is intended and no endorsement by the
U.S. Department of Agriculture is implied.
USDA prohibits discrimination in its programs
on the basis of race, color, national origin, sex,
religion, age, disability, political beliefs, and
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(Braille, large print, audiotape, etc.) should
contact USDA's TARGET Center at (202) 720-
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write the Secretary of Agriculture, U.S.
Department of Agriculture, Washington, DC
20250, or call (800,1 245-6340 (voice) or (202)
720-1127 (TDD USDA is an equal opportu-
nity employer.

Agricultural Research

Public-Private Partnership Boosts Public Benefits 4

Harvester Picks Ripe Citrus Faster 8

Pest-Proofing Food Packaging 1 0

Foods, Phytonutrients, and Health 12

Vegetarians, Watch Your Zinc! 1 03

Women May Need More Folate 14

Special Dietary Guidelines for Teenage Mothers 17

Vitrification Keeps Pig Embryos Viable 19

Compression Puts the Squeeze on Hay Pests 21

Tackling Ticks That Spread Lyme Disease 22

Altered Baculovirus Dooms Corn Earworms 25

Insect Salivary Proteins Prevent Blood Clotting 26

Science Update 27

Cover: For more than half a century, scientists at the USDA-ARS National Center
for Agricultural Utilization Research in Peoria, Illinois, have searched for innovative
agricultural products and technologies of interest to processors and consumers. Some
of the research has focused on using injection-molding equipment to shape new
starch-based products. Photo by Keith Weller. (K8005-2)

In the next issue!

0- USDA's Agricultural Research Service is joining in NASA's
Mission to Planet Earth project to study how soil moisture affects the

'0 A new composting center for plant material in Beltsville, Maryland,
takes recycling full circle.

*' Complaints about livestock odors in rural areas have become a
national problem. Now a new mechanical "nose" can quickly identify
more than 200 airborne volatile organic compounds, gases, and particles
from livestock operations.

Agricultural Research/March 1998

Public-Private Partnership Boosts

Public Benefits

I n the early years of the 20th
century, Peoria, Illinois, was a
proving ground for new ideas
and enterprises in the burgeon-
ing entertainment field called
vaudeville-so much so that the
phrase, "How will it play in Peoria?"
became a standard in the American
vernacular. Eventually, the saying
came to apply to everything from
politics to fashion.
More than half a century later, a
group of Peoria businessmen re-
newed the town's proving ground
tradition in a totally different arena.
They sought a way to bridge the gap
between exciting discoveries made in
government laboratories and a
marketplace eager to receive those
discoveries in a commercial form.
The businessmen's goal was to marry
government and academic research
expertise with private industry's solid
marketing know-how.
The resulting union was the
Biotechnology Research and Devel-
opment Corp., or BRDC, formed in
1988 and headquartered at the
National Center for Agricultural
Utilization Research in Peoria.
NCAUR is operated by the Agricul-
tural Research Service, USDA's
chief research agency.
Unlike their neighbors down the
hall at NCAUR, personnel in the
BRDC do not conduct research.
Instead, they concentrate on
"discovering and funding technology
that holds promise to make a signifi-
cant impact on the international
marketplace," says BRDC's president
and chief executive officer, J. Grant
Brewen. Of special interest are
agriculture-based technologies and
new market opportunities for renew-
able agricultural commodities, such
as corn, wheat, and soybeans.

Although agricultural commodi-
ties are often in the spotlight at
BRDC, the corporation's creation
was firmly rooted in the depressed
industrial economy of the early
1980s. Among the founding mem-
bers of the new venture was Del
Schneider, who is now retired but
was then chief executive officer of
CILCORP Ventures, Inc., of Peoria,
a subsidiary of CILCORP (Central
Illinois Light Corporation).
Schneider sought a way to spur
economic growth for the Peoria area.


Chemist J.L. Willett prepares a test
specimen for the evaluation of mechanical

"Mr. Schneider put forth the idea
for BRDC with the goal of diversify-
ing the community's industrial base,
which relied heavily on the manufac-
ture of construction equipment,"
recalls Thomas Romanowski, vice
president of finance for CILCO, also
a subsidiary of CILCORP.

Built on Legislative Supports
Important federal legislation
passed in the mid-1980s helped
make BRDC a workable reality-
specifically, the Federal Technology
Transfer Act of 1986 that smoothed
the way for government researchers
and private enterprise to work to-
gether. This legislation allowed
government agencies such as the
Agricultural Research Service to
establish cooperative research and
development agreements
In return for signing on as partners
on a project under a formal CRADA,
industry cooperators are given first
crack at a license to market the re-
sulting technology. This opportunity
makes cooperation with government
researchers much more appealing to
industry. Thus, BRDC was born to
facilitate these collaborations.
Industry has been a crucial player
in BRDC. From the beginning, each
company represented on BRDC's
board of directors paid a $200,000
annual membership fee to help fuel
the corporation. In 1997, this fee was
reduced to $50,000 per year. Other
funding for the enterprise has come
from a one-time $4 million grant
from the Illinois Department of
Agriculture and $2.5 million annual-
ly in federal grant money. In addition
to the company representatives, the
BRDC board includes representa-
tives from ARS and the Agricultural
Research Development Corp., which
administers the federal grant money
to BRDC.
A scientific advisory board
composed of representatives of the
member companies and ARS solicits
projects in targeted research areas at
government and academic laborato-
ries that meet the technology inter-

Agricultural Research/March 1998


Physical science aid
Ashle. Maness and
technician Tim Bond
calibrate a feeder
used to accurately
meter starch into a
twin-screw extruder
for processing of

.d *


Agricultural Research/March 1998


ests of BRDC member companies.
To date, BRDC has provided more
than $30 million in funding that
benefited 140 research projects at 37
institutions and earned more than
$1.5 million in licensing fees, Bre-
wen says.
The real-world effects have been
dramatic: BRDC-funded research has
led to the filing of 230 patent applica-
tions, with 43 patents issued thus far.
BRDC has also entered into 49
license and option agreements for
technologies that have resulted from
public-private collaborations.
BRDC's government-industry
research matchmaking has led to
such diverse benefits as therapeutic
drugs for medical applications,
specifically in the treatment of
human immunodeficiency virus
(HIV), technology to predict swine
litter size, an effective vaccine
against cattle shipping fever, and a
new method of cloning swine that is
now being tested in leading animal
science laboratories.
These results are in keeping with
BRDC's impressive launch, which
included among its initial sharehold-
ers The Dow Chemical Co.; Ameri-
can Cyanamid Co.; Amoco Technol-
ogy Co.; CILCORP Ventures, Inc.;
Hewlett Packard Co.; ECOGEN,
Inc.; and the International Minerals &
Chemicals Corporation (now
Mallinckrodt, Inc.). Original research
institutions were the University of
Illinois and ARS' Northern Regional
Research Center, later renamed the
National Center for Agricultural
Utilization Research.
A decade later, the shareholder
mix has changed only slightly,
Brewen says, but the scope of
technologies being explored and
brought to market has expanded.
Today's BRDC shareholder lineup
includes The Dow Chemical Co.;
Mallinckrodt, Inc.; Alexion Pharma-
ceuticals, Inc.; Dalgety PLC; Mc-

ARS physical science aid Ashley Maness
checks the operation of a starch feeder
before extrusion processing.

Donald's Corp.; American Home
Products Corp.; and Schering
Plough, Inc.

Evaluating the Aftereffects
The impact of the 1986 Technol-
ogy Transfer Act on the focus,
direction, and ultimate marketability
of publicly funded research has been
tremendous, says Richard L. Dunkle,
director of ARS' eight-state Midwest
Area and an ex-officio member of
the BRDC board.
Prior to that legislation, companies
weren't especially interested in
signing on as partners with govern-
ment researchers. Back then, the
ultimate fruits of the research were
readily available to anyone who
cared to market them, with no
particular benefits to the company
that poured its time, money, and
expertise into the joint project. The

lure of marketing rights-as prom-
ised by the Technology Transfer
Act-encouraged public-private
While basic and exploratory
research is vital, it is also time-
consuming and expensive, making it
less attractive to private businesses
to tackle on their own, Dunkle says.
"Private industry couldn't afford
the time or the money for this
fundamental research, whereas the
government has been charged with
developing solutions to problems
through fundamental research."
Ensuring that new technologies
developed in government laborato-
ries are adapted and used is a major
responsibility of federally funded
research programs. However, as
Dunkle points out, "The information
and findings that resulted from the
government research were not being
utilized by private industry to the
fullest extent."

Out of the Laboratory, Into the
NCAUR Director Peter B. John-
sen describes the one-time discon-
nect between government research
and private industry even more
succinctly. He's dubbed it a "Death
"Important technology develop-
ments from government research
often ended without the pull-through
that private industry provides in
converting a concept or invention
into a commercial reality," he says.
The allure of CRADAs has
resulted in emergence of new
technologies from government-
industry partnerships in a matter of
months or a few years, compared
with a decade under the old system.
The new system ensures that the
technology that emerges from a joint
project will actually be born. One
parent, the government research

Agricultural Research/March 1998

Starch can be processed with a variety of
biodegradable resins and injection-molded
into disposable items such as cutlery.
Understanding the materials science of
these blends is critical to advancing the
technology to the marketplace.

entity, conducts the long-term and
sometimes high-risk research. The
industry parent contributes know-
how about adapting the technology
commercially and marketing it.
According to industry insiders, it's a
win-win arrangement for companies
like The Dow Chemical Co. that
have worked with ARS under
CRADAs to develop marketable
"This new relationship between
private and public sectors is very
critical to the continued success of
American business," says Bill
Dowd, Dow's research and develop-
ment director.
"Our membership in BRDC has
been very valuable," he continues.
"It has given us ready access to basic
research and the expertise of ARS
scientists. This means we didn't
have to 'reinvent the wheel' and

duplicate this knowledge in our own
Without the working partnership
facilitated by BRDC, Dowd says, it is
unlikely Dow would have considered
some of the technologies it has
developed and marketed in the past
10 years.
"Frankly, the cost of basic research
in some areas, such as starch and its
use in composite materials, would
have been prohibitive," he says.
"Many technologies simply would
not have gone past the idea stage."
Dowd sees BRDC as a vehicle for
vertical integration of government,
academia, and industry. The three en-
tities share among themselves infor-
mation, research, product develop-
ment, and marketing strategies that
none could afford on its own. That
lowers costs for business and speeds
government research to the market-
place-and the consumer-much
This means taxpayers win, too,
since their tax dollars are put to work
funding relevant basic research in
areas important to their day-to-day
Technologies with a direct link to
the agriculture community include
development of starch-encapsulation
of insecticides and new technologies
for biological control agents.
"We in industry have done a poor
job of defining what is relevant
research," says Dowd. "We need to
be more specific, so the basic science
being done at our public institutions
and government laboratories can be
moved forward. Working with ARS
and universities through BRDC, we
see a greater potential to leverage
everyone's capabilities."
The public wins in the end, Dowd
says, because the resulting technolo-
gies use those renewable resources
produced in the rural economy.

An injection-molding machine is used to
prepare test samples for measurement of
properties like strength and stiffness. Here,
BRDC technician A.J. Thomas checks the
quality of a freshly molded set of

"The best small business people in
the world today are American
farmers," he says. "As we bring more
and more technology to focus on
what the farmer can produce, it helps
Dow grow as a company. And it
helps farmers expand markets for
their basic products."-By Dawn
Lyons-Johnson, ARS.
Peter B. Johnsen directs the
USDA-ARS National Center for
Agricultural Utilization Research,
1815 N. University St., Peoria, IL
61604; phone (309) 681-6542, fax
(309) 681-6682, e-mail
J. Grant Brewen is the chief
executive officer of Biotechnology
Research and Development Corp.,
1815 N. University St., Peoria, IL
61604; phone (309) 688-1188, fax
(309) 688-1292, e-mail *

Agricultural Research/March 1998

A Real Mover and Shaker

Harvester Picks Ripe Citrus Faster

A new mechanical harvester
could revolutionize the
U.S. citrus industry by
making our growers competitive with
Brazilian growers and giving them an
edge on the orange juice market.
Just as large-scale machine produc-
tion wrought dramatic changes during
the Industrial Revolution of 1750-
1850, this new harvester is expected
to forever change the U.S. citrus in-

oped and patented a new shaking con-
cept for harvesting blackberries.
"We used this harvester successful-
ly on blueberries in 1993, prompting
Blueberry Equipment, Inc. (BEI) to li-
cense the technology," says Peterson.
Subsequently, Peterson and BEI, a
company based in South Haven,
Michigan, developed a commercial
mechanical harvester for fresh-market
blueberries. This harvester helps blue-

ARS agricultural engineer Donald Peterson (left) and Galen Brown, harvesting program
administrator for the Florida Department of Citrus, examine fruit harvested by ARS' new
canopy shaker.

dustry. By shaking a citrus tree's foli-
age, it can harvest a 90-pound field
box of citrus for 50 cents-compared
to the $1.50 it now costs. And it can
harvest the 300 to 400 field boxes of
fruit from each orchard acre 15 times
faster than hand laborers.
It all began in 1988 when Donald
L. Peterson, an agricultural engineer
at the Agricultural Research Service's
Appalachian Fruit Research Station in
Kearneysville, West Virginia, devel-

berry growers decrease their reliance
on hand labor for harvesting. Most
fresh-market fruit is hand picked. Not
only is hand labor expensive, but
there is no guarantee that it will be
available when needed.
Most citrus is also harvested by
hand. Although trunk shakers-which
are different from foliage shakers-
are starting to be used, they're only
effective in certain types of groves.

Effective trunk shaking of Valencia
oranges, with both this year's and next
year's crops on the tree, requires that
a chemical fruit loosener be sprayed
on the trees to loosen mature fruit be-
fore it is shaken. There is no chemical
yet approved for this use. With the
new harvester, no loosening chemicals
are needed.
In 1995, Peterson was approached
by Galen K. Brown, harvesting pro-
gram administrator for Florida's De-
partment of Citrus (DOC). Brown, a
former ARS scientist, was looking
into mechanically harvesting citrus
grown for juice processing. DOC
signed a cooperative research and de-
velopment agreement with ARS to
further investigate the possibility of
mechanically harvesting citrus using
Peterson's technology.
"Between 90 and 95 percent of
Florida's citrus goes for processing,
leaving about 10 percent for fresh and
specialty markets. To harvest this
crop, Florida growers employ about
45,000 seasonal workers during peak
season," Brown reports.
"Although employers have com-
pleted all requirements to hire season-
al migrant workers, immigration regu-
lations could eventually limit hiring
enough laborers to harvest our citrus
crop. Therefore, we must have some
alternative system in place within the
next few years," says Brown.
"We must also become more com-
petitive. Brazilian citrus growers can
now get their fruit off the tree for one-
third of what it costs our growers.
This means that they can put their
juice in our stores at a substantially
lower price and still make a profit. It
now costs us about as much to get the
fruit off the tree and to processors as it
costs to grow it."
The new harvester looks somewhat
like a giant hairbrush, except its nylon
"bristles," or spikes, are about 12 feet
long and rotate as well as shake. It is
pulled by a tractor continuously mov-

Agricultural Research/March 1998

Currently, it costs Florida producers about as much to get
the fruit off the tree and to processors as it does to grow it.

ing between rows of orange trees at
about I to 2 miles per hour.
The spikes go about 5 feet into a
tree's canopy and gently shake it.
Fruit falls onto a conveyor belt that
carries it to the back of the machine
and transfers it to a self-propelled
bulk transport unit that holds about 6
tons. This unit follows the harvester
at a synchronized speed.
Both the harvester and the trans-
port unit have built-in trash removal
systems. Leaves and dirt drop to the
ground on the rod conveyor system,
and there is a brush for removing
Peterson, with help from KEITH WE
technician Scott Wolford,
built a prototype of the har-
vester at Kearneysville and
tested it on Florida citrus
groves in 1996 and 1997.
"We rem ved up to 95
percent of the mature fruit
from trees, and its quality
was as good as hand-har-
vested fruit," Peterson re-
ports. "The machine har-
vested between 7 and 9 trees
per minute, while a conven-
tional trunk shake-catch har-
vester can do 2 to 3 per Twelve
minute. And it is up to 15 citrus t
times more efficient than
hand labor, depending on
the size and yield of the
Agricultural Machines, Inc., an
Avon Park, Florida, company run by
Tom Visser, built handling and haul-
ing equipment compatible with the
harvester. This allows removal of the
fruit from the grove to the roadside,
where it is dumped into tractor trail-
ers for hauling to processors.
Turner Foods of Punta Gorda, a
subsidiary of Florida Power and
Light Group, grows 18,000 acres of
oranges for processing in southern
Florida. Turner also markets pro-
cessed citrus products nationwide to

supermarket chains, like Safeway, and
employs about 1,000 seasonal workers
from October through May.
"We must lower harvesting costs,"
says Maurice Gebhardt, Turner's di-
rector of technical services. He is also
chairman of DOC's Citrus Harvesting
Research Advisory Council.
Gebhardt, a former engineer with
ARS, convinced Turner to become a
partner in commercializing Peterson's
new harvesting technology. "The trial
harvests in 1996 and 1997 were excit-
ing. We learned that the harvester had
great potential but needed modifica-

-foot-long nylon rods rotate and shake foliage along r
rees being machine-harvested in Parrish, Florida.

tion to make it a complete system. So
we began working directly with BEI
to develop a commercial prototype for
the 1997-98 harvest," he says.
Since Blueberry Equipment, Inc., is
the licensed manufacturer of the har-
vester, it built the new machine to spe-
cific modifications Peterson suggested
for the citrus industry.
"We built two machines, so that we
could harvest both sides of the citrus
tree at the same time," says Butch
Greiffendorf, BEI general manager.
Greiffendorf says the machines,
which are simple with few moving

parts, are built rugged to endure the
sand, terrain, and long season of
Florida's citrus groves.
A disadvantage to machine pick-
ing, according to Brown, is that Flor-
ida's citrus plantings are diverse,
with trees of all ages, sizes, and spac-
ings. Although hedging is a common
practice, the groves planted before
the mid-1980s don't have uniformly
flat fruiting walls, which are ideal for
this mechanical harvesting system.
"However, I'd say that 20 percent
of Florida's existing citrus acreage
can be easily adapted to Peterson's
new harvester, and new
plantings may be set spe-
cifically for it," says
S Brown. "And we don't
need any chemicals to
loosen the fruit for this
"Florida orange growers
are definitely interested in
this concept. And grape-
fruits are easier than
oranges to harvest, so
those growers are also
likely to be interested."
"Growers' acceptance
of the citrus harvester will
ows of mean that they can harvest
more cheaply than before,
control when they harvest,
and know that their equip-
ment is dependable,"
Peterson says. "Consumers will ben-
efit, because harvesting costs will be
lowered and plenty of juice will be
available."-By Doris Stanley,
Donald L. Peterson is at the
USDA-ARS Appalachian Fruit Re-
search Station, 45 Wiltshire Rd.,
Kearneysville, WV 25430-9425;
phone (304) 725-3451, extension
324, fax (304) 728-2340, e-mail
dpeterso@usda.afrs.naa.ars. gov *

Agricultural Research/March 1998

Pest-Proing Food Pki

N o one wants to open their
breakfast cereal or pancake
mix and find it infested
with bugs. Even if these occurrences
represent one in a million, they make
a lasting impression.
Manufacturers of food, feed, and
other processed grain products want
to avoid these incidents and provide
consumers with high-quality prod-
ucts. That's why ARS entomologist
Michael A. Mullen at the Grain
Marketing and Production Research
Center in Manhattan, Kansas, has
been working with food and feed
manufacturers since 1989 to help
design insect-proof packaging.
"Packaging should protect the
commodity from the point of manu-
facture to the point of consumption,"
says Mullen. Nine times out of 10, an
insect infestation
isn't the manufac-
turer's fault. Most stoi
Often, insects get
into packages inSects a1
during transporta- entering fc
tion or storage in a package
warehouse. seams ar
Like people
who fall into two
basic personality
types-uptight A
or laidback B-stored product insects
are one of two types. They're either
invaders or penetrators.
"The invaders look for opportuni-
ties to get inside food containers by
searching for cracks, crevices, and
holes," says Mullen. "The penetrators
simply chew holes in the packages."
Invaders include the red flour
beetle, confused flour beetle, saw-
toothed grain beetle, Indianmeal
moth, and almond moth. Penetrators
like the lesser grain borer, cigarette
beetle, warehouse beetle, and rice
moth can bore through one or more
layers of packaging materials.
"There is no perfect package,"
says Mullen. "Packages are usually

tailored to fit the product and de-
signed to last throughout its shelf
life. Often, this means that the
package will have to provide this
protection for more than a year."
Although packages can become
infested anywhere along the market-
ing chain, they are most likely to be-
come infested during long-term stor-
age. Inside warehouses, insects start
by attacking vulnerable packaging
and later jump to sturdier material.
Most stored-product insects are
invaders, entering food and feed
packages through seams and clo-
sures. They lay their eggs in the tight
spaces formed when packages are
folded. These spaces give the newly
hatched larvae an ideal starting spot
to invade. Dry pet foods are usually
packaged in bags like these.

re invaders,
od and feed
3s through
d closures.

bag bottoms were prone to insect
entry and needed reinforcement as
much as top closures. Mullen is
helping one bag manufacturer
expand its customer base from
nonfood agricultural products to
food products.
Another packaging problem
involves smell. Insects are attracted

Mullen has
been working with
several companies
that make dry pet
food and with oth-
ers that produce
paper bags used
for its packaging.
In November
1997, ARS and
Mullen initiated a
cooperative re-

search and development agreement
(CRADA) with International Paper
of Loveland, Ohio, to improve exist-
ing packaging or develop alternative
packaging to protect dry pet foods
from insect damage.
Other companies that Mullen has
had formal CRADAs with include
Ralston Purina in St. Louis, Missou-
ri, and Continental Extrusion Com-
pany in New Jersey.
Seals and closures can often be
improved by changing the type or
pattern of sealant glue. A pattern that
forms a barrier is usually the most
insect resistant. Recently, paper bag
manufacturers discovered through
working with Mullen that closures on

Entomologist Mike Mullen checks seals
for signs of infestation after a 3-month
test of consumer-size packages.

Agricultural Research/March 1998

to packages that allow food odors to
escape. Certain plastic film over-
wraps that fit tightly around a
package can help prevent insects
from smelling its contents. Interior
plastic liners like those used in
breakfast cereal boxes can be
effective, blocking air from carrying
aromas outside to hungry insects.

In 1991, Mullen helped to
develop an odor neutralizer that can
be incorporated into packaging
materials. He devised a laboratory
choice test allowing insects to
choose between a food protected by
the odor neutralizer or by only
untreated packaging. They chose the
food in untreated paper.

Dry pet food is a favorite
food of insect pests such as
these flour beetles.

"There's really no one thing that
makes a package insect proof," says
Mullen. "Each additional improve-
ment added to the package design
helps keep insects out. All packages
provide some protection against
invasion. But tightening up the seals
and adding a repellent adds even
more," he says.
Mullen has developed scientifi-
cally proven methods to evaluate
packaging materials against insects
in the laboratory. He places 32 to 40
of each package type in an environ-
mentally controlled room for about 3
months. These packages are exposed
to five species of insects. Each
month, the researchers examine
packages for holes and flaws in
seams and closures. Finally, they
open the packages and examine the
contents for insect infestations.
Manufacturers rely on these
findings to improve future package
designs or to conduct larger packag-
ing studies. Test results have led to
insect-resistant, pesticide-free
packages for dry pet foods, raisins,
baby cereals, pancake mixes, and
breakfast cereals for domestic
consumption and export. One
company has reported a 75-percent
reduction in consumer complaints
from insect-related problems.
The food industry is facing
increasing restrictions on pesticide
use. Insect-resistant packaging can
help reduce dependence on insecti-
cidal treatments. This research helps
assure consumers of insect-free food
and protects manufacturers against
loss of goodwill arising from insect-
infested packaging.-By Linda
Cooke, ARS.
Michael A. Mullen is in the
USDA-ARS Biological Research
Unit, Grain Marketing and Produc-
tion Research Center, 1515 College
Ave., Manhattan, KS 66502; (785)
776-2782, fax (785) 537-5584, e-
mail mullen *

Agricultural Research/March 1998


_ mm .m.m.

D discoveries in the nu-
trition and health arenas
A i t h 1 t h*-

ana n


widened our view of what By Carla R. Fjeld, USDA-ARS National
foods do for us-from Program Leader for Human Nutrition
supplying raw energy to
providing the vitamins and
minerals that the body
needs to function. More recently, these sciences have est nutritional values-an
come to recognize that plant foods contain a virtual cornu- tonutrients in forms the bo
copia of compounds-over and above vitamins and miner- This will require more t
als-that potentially enhance human health. engineering. For instance,
Examples include cruciferous vegetables such as broc- the quality of soil affects r
coli and cauliflower that can blunt tumor growth in animal ping, while it has given us
models, phytoestrogens in soybeans that appear to reduce yield the most nutritious p
risk of breast cancer, and plant anthocyanins-or color Similarly, harvesting, st
pigments-that appear to reduce the rate of oxidative dam- affect the nutritional value
age within the human body. ample, harvesting fruit we
These plant, or phyto-, nutrients are not essential for the Americans to purchase un
body's day-to-day operation. But they appear to be in appears that plants synthes
foods for good reason. They may protect DNA and other during the latter stages of
cell parts from oxidation, detoxify environmental pollut- duction. If so, that means t
ants, deactivate carcinogens, boost the immune system, or would be the most healthfi
act in as yet unknown ways to prevent or delay onset of According to recent sur
cancer, heart disease, cataracts, and other diseases related ingly concerned about the
to the foods we eat or don't eat. Together, diet-related dis- question is: Are we willing
eases in the United States cost more than $200 billion for quality and flavor, or would
care and medical treatment each year. out of season? As we have
The discovery of phytonutrients has stimulated much some consumers will seek
excitement among nutrition and health scientists. Now it the taste is improved.
challenges us to translate new findings into a food supply But we have to be care
that enhances health with aging. Traditionally, agricultural food supply that targets he
and nutrition sciences have gone along separate paths- long-range planning, coor
one to produce and deliver whole foods, the other to iden- portantly, a change in min
tify individual nutrients and learn how they work in the the Agricultural Research
body. Now these two sciences will have to work together and workshop this month-
to bring the phytonutrient promise to fruition. Keynote speakers at the
For its part, nutrition research will need to shift its focus Health conference will adc
toward whole foods and diets for reaching optimum dustrial perspectives on p
health, rather than simply toward preventing deficiencies workshops, invited guests
of individual nutrients. industry will discuss how 1
Before we can identify the most beneficial phytonutri- identify research priorities
ents, researchers need to develop better methods of moni- velop partnerships among
touring how these compounds affect human health. For ex- sciences, and the food indt
ample, there's plenty of epidemiological evidence linking also give federal validation
a high fruit and vegetable intake with reduced risk of entists within ARS and un
chronic diseases. But we need early predictors-or bio- neered the discovery of ph
markers-of these diseases to test the ability of foods and Address comments to CG
their components to prevent them. The other partner, agri- 005, 10300 Baltimore Ave.
cultural research, will need to broaden its thinking to make phone (301) 504-6216, fax
human health a key target. It will take the coordinated ef- *

forts of plant physiologists,
breeders, genetic engi-
neers, soil scientists, agri-
cultural engineers, and
food marketing and distri-
bution experts to ensure
that our crops reach the
family table with the high-
I with essential nutrients and phy-
>dy can easily assimilate.
than just plant breeding or genetic
it's becoming more evident that
nutritional value. Intensive crop-
efficient production, may not
storage, and distribution practices
of fruits and vegetables. For ex-
11 before it is ripe has enabled
spoiled produce year round. But it
size many of their phytonutrients
ripening, along with sugar pro-
he produce picked the latest
ul-as well as being the tastiest.
veys, U.S. consumers are increas-
nutrient value of their foods. The
g to pay higher prices for top
ld we forego our favorite fruits
better evidence of health effects,
out these products-especially if

ul to not run ahead of science. A
alth as a top priority requires
dination, and, perhaps most im-
dset. To facilitate this transition,
Service is sponsoring a forum
-National Nutrition Month.
Food, Phytonutrients, and
Iress health, plant science, and in-
hytonutrients and health. In the
from government, academia, and
to fill current gaps in knowledge,
, and look for opportunities to de-
nutrition sciences, agricultural
istry. We hope the gathering will
i to the efforts of individual sci-
iversity programs who have pio-
arla R. Fjeld, Rm. 332A, Bldg.
, Beltsville, MD 20705-2350;
(301) 504-6231, e-mail

Agricultural Research/March 1998

Vegetarians, Watch Your Zinc!

Zinc. This four-letter trace ele-
ment helps the body guard against
infections and repair wounds. It's
essential for growth and brain
development in infants and children.
So ARS nutritionist Janet Hunt
wanted to know if vegetarians-at
least those who consume milk and
eggs-get enough zinc to support
these and the hundreds of other
biological functions in which the
mineral participates.
A recent survey done by the
Vegetarian Resource Group tallied
nearly 2 million lacto-ovo vegetari-
ans in the United States. More
common than vegans, who exclude
all animal products, lacto-ovo
vegetarians include milk and eggs in
their diets.
"But about 44 percent of the zinc
in most U.S. diets comes from meat,
fish, and poultry," says Hunt. "These
are the foods that all vegetarians
She says planning the vegetarian
diet to contain as much zinc as the
typical U.S., or Western, diet used in
the study was challenging.
"It required the daily inclusion of
legumes, such as beans and peas, and
considerable use of whole-grain
products," says Hunt. And it still fell
short-by 14 percent, she says.
Vegetarian diets in the United
States typically contain between 10
and 30 percent less zinc than nonveg-
etarian diets.
And they also contribute a lot of
fiber and phytic acid, which tend to
tie up minerals and make them less
available for absorption. But the net
impact of including high-fiber, high-
phytic-acid foods such as legumes
and whole grains is probably posi-
tive, says Hunt. "Absorbing 8
percent of the 3.5 milligrams (mg) of
zinc in a slice of whole-wheat bread
is still better than absorbing 38
percent of the 0.4 mg of zinc in a
slice of white bread."

Twenty-one women consumed
both the vegetarian diet and the
typical U.S. diet for 8 weeks each
while living at the Grand Forks
Human Nutrition Research Center in
North Dakota. Hunt and colleagues
measured the women's absorption of
zinc and another trace element-
iron-using nonharmful radioactive
isotopes. Although vegetarian diets
supply ample iron, the iron in plant
foods, called non-heme iron, is not as
well absorbed as the iron in animal
The women, indeed,
absorbed less zinc from KEITH WELER
the vegetarian diet-21 (
percent less. Combined III
with the 14 percent
lower zinc content of the
vegetarian diet, the
women absorbed a total
of 35 percent less zinc.
And their blood zinc
levels were 5 percent
lower after 8 weeks on
the vegetarian diet.
"But they absorbed
enough zinc to replace
the amount excreted and
didn't seem to be at any health risk,"
says Hunt.
She concludes that lacto-ovo veg-
etarians, while at greater risk for zinc
deficiency, can meet their require-
ments by eating plenty of whole
grains and legumes. She sees a much
greater risk of zinc deficiency in eco-
nomically disadvantaged countries
where vegetarian diets contain more
phytic acid and less protein, an en-
hancer of zinc absorption.
The women's absorption of non-
heme iron was also lower on the
vegetarian diet-70 percent lower.
And this diet contained none of the
heme iron supplied by the typical
U.S. diet, so total iron absorption
was even lower. But again, the
women showed no signs of iron-poor
blood, based on hemoglobin and

several other measurements. One of
these-serum ferritin-is considered
the most sensitive indicator of iron
stored in the body.
"There's a range where people
can absorb more or less and still not
be at risk of toxicity or deficiency,"
Hunt says. "Although several
surveys indicate that vegetarians
have lower iron stores, blood hemo-
globin remains normal, and there's
no evidence of impaired function."
The researchers also assessed the
women's balance for several miner-
als in addition to
7-8) zinc and iron.
People are said to
be "in balance"
for a given
mineral when
they are consum-
ing as much as
they are losing
through urine,
Sfeces, sweat, or
other bodily
The vegetarian
ks diet contained
about the same
amount of calcium as the Western
diet and a little less phosphorus. But
it supplied 27 and 29 percent more
copper and magnesium, respectively,
and more than twice the manganese.
Still, balance measurements didn't
differ significantly between the two
diets for any of these minerals or for
zinc and iron.
"It shows how well the human
body adapts to changes in both the
amount and form of minerals and
maintains an equilibrium," says
Hunt.-By Judy McBride, ARS.
Janet R. Hunt is at the USDA-ARS
Grand Forks Human Nutrition
Research Center, P.O. Box 9034,
University Station, Grand Forks,
ND, 58202-9034; phone (701) 795-
8328, fax (701) 795-8393, e-mail *

Agricultural Research/March 1998

Women May Need More Folate

:" 1ore evidence that the
i. current Recommended
Dietary Allowance of 180
micrograms a day of the B vitamin
folate (folic acid) for women is
probably too low has resulted from a
new study by ARS researchers and
their colleagues.
Adequate folate intake has been
linked to decreased risk of spina
bifida and other birth defects, as well
as reduced risk of cardiovascular
disease and stroke.
"A very small amount of the
powdered form of folate," says ARS
chemist Robert A. Jacob, "provides
the RDA. It's the quantity of this
nutrient found in 1-3/4 cups of
orange juice or about 4/5 cup cooked
red beans, for example." Other foods
rich in folate include dark-green
leafy vegetables like spinach and
broccoli, peas and beans, nuts and
seeds, eggs, and liver.
Jacob led the folate investigation
of 10 healthy, post-menopausal
volunteers, age 49 to 63. They lived
round-the-clock at the ARS Western
Human Nutrition Research Center in
San Francisco. For 9 weeks, they ate
meals that provided 30 to 60 percent
of the RDA for folate. For a final 3
weeks, they got meals fortified with
extra folate.
The center's dietary staff meticu-
lously prepared and measured the
volunteers' meals. "We tried to
provide familiar foods and to mimic
the eating patterns of women who
don't get enough folate-containing
fruits and vegetables," says Jacob.
To remove about half of the folate
from green beans, carrots, chicken,
turkey, and ham, the dietary staff
boiled these foods three times,
discarding the water each time.
Volunteers ate a standard menu of
low-folate foods throughout the
study, supplementing it at breakfast
and dinner during the last 7 weeks

Chemist Robert Jacob discusses progress of a 12-week folate study with participants Carol
Garnett (right) and Maria Salazar.

with pure, synthetic folic acid mixed
with applesauce.
A typical day's menu might
include applesauce and hash-
browned potatoes or applesauce and
toast with jelly for breakfast; boiled
chicken, noodles, zucchini squash,
and stewed tomatoes for lunch; and
pasta, roast turkey, carrots with
Italian dressing, and applesauce for
dinner. That day's evening snack
would be a light dessert made of
carrots, margarine, sugar, and a
nondairy topping.

Women of childbearing age were
excluded from the study because of
the link between low folate levels and
increased risk of spina bifida and
other neural tube birth defects, that is,
deformities of the brain or spinal
cord. To help prevent these birth
defects, the U.S. Food and Drug
Administration requires-as of
January 1, 1998-that enriched bread,
flour, cornmeal, rice, pasta, and other
grain products be fortified with folate.
[See "Foods To Be Fortified With
Folic Acid," Agricultural Research,
June 1997, pp. 16-17.]

Another Measure of Folate Status
After the 9-week regimen of low
folate, the researchers found that all
of the women had low levels of
folate in their blood (plasma). And
seven of the women had a larger
number of components called
micronuclei in their white blood
Says Jacob, "An increase in
micronuclei indicates damage to
DNA in chromosomes. DNA is the
genetic blueprint for all cell growth.
Damage and repair to DNA is

always occurring, but chronic DNA
damage may overwhelm repair
mechanisms and increase the risk of
cancer and birth defects.
"The micronucleus test," notes
Jacob, "wasn't used to study folate
nutrition in 1989, when folate RDAs
for adults were lowered from 400
micrograms to 200 micrograms for
men and 180 micrograms for
The idea of raising the folate RDA
isn't new. But the San Francisco test
was apparently
the first to use BRIAN PRECHTEL (K7989-7)
white blood cell
counts in a
controlled study
of moderate
folate deficiency.
The scientists
used a second
technique to
check the body's
DNA. Explains "
Jacob, "The body
uses folate to
supply one-
carbon-units in
many reactions, a
process called
methylation. Technician Janet Ch
That happens amount of B vitamin
during formation dish of applesauce.
of DNA, for
instance. Methyl-
ation of white blood cell DNA
decreased during the low-folate
regimen. Other researchers have seen
that happen in animal tests. But our
experiment was the first to show that
even a mild folate deficiency can
reduce methylation of DNA in
Seven of the 10 volunteers had
elevated levels of an amino acid,
homocysteine, in their blood by the
time they completed the first 9 weeks
of the 3-month study.

ian a

"The body," Jacob says, "has a
folate-based mechanism to keep
homocysteine from getting too high.
It uses a form of folate called methyl-
tetrahydrofolate to convert homocys-
teine into a different amino acid,
methionine. It's another example of
methylation. High homocysteine
levels increase risk of heart attack or
For 2 weeks following the low-
folate stint, volunteers received 160
percent of the RDA. That raised
plasma folate, but
levels remained
high in half of the
Says Jacob,
"This indicated
that the current
RDA may not be
sufficient to
maintain safe
levels in women
Swho consume
low-folate diets
similar to what
was fed in this
During the last
adds a precise week of the study,
ate solution to a when the women
were given nearly
three times the
RDA, homocys-
teine levels decreased to normal, or
near normal, in all but one of the
volunteers, whose level still remained
above normal at the end of the study.
Plasma folate, white blood cell
micronuclei counts, and DNA
methylation also returned to their pre-
study levels.
Jacob did the work with ARS
colleagues Denise Gretz and Peter C.
Taylor at the nutrition center; Marian
E. Swendseid of the University of
California at Los Angeles; S. Jill

Agricultural Research/March 1998 Agricultural Research/March 1998

James of the U.S. Food and Drug
Administration, Jefferson, Arkansas;
Tsunenobu Tamura of the University
of Alabama at Birmingham; and
Nina Titenko-Holland of the Univer-
sity of California at Berkeley.
Folate deficiency has been linked
to increased risk of cancer of the
cervix, intestine, and other parts of
the body that have a lining of epithe-
lial cells. So the team also examined
micronuclei counts in epithelial cells
from the inside of the cheeks. Using
a toothbrush, cells were gently
scraped from the cheeks of each
volunteer. Cheek-cell tests are used
in other nutrition and toxicology
Titenko-Holland found that
cheek-cell micronuclei didn't
increase during the low-folate phase.
But they decreased after the final 3
weeks of higher folate menus.
In an earlier experiment, Jacob
and Swendseid had shown that the
RDA for adult males may not be
adequate. Four of the 10 volunteers
who ate 12 percent of the folate
RDA showed moderately elevated
homocysteine levels. These levels
remained elevated even when the
volunteers received 84 percent of the
"Raising the RDA for men-as
well as women," says Jacob, "would
increase the margin of safety for
maintaining healthy homocysteine
levels. When the folate RDA was set
8 years ago, homocysteine levels
weren't measured. Nor was the
connection of high homocysteine
with heart disease known at that
time."-By Marcia Wood, ARS.
Robert A. Jacob is at the USDA-
ARS Western Human Nutrition
Research Center, P.O. Box 29997,
Presidio of San Francisco, CA
94129; phone (415) 556-3531; fax
(415) 556-1432; e-mail *

A typical meal served in the folate study included pasta, tomato sauce, and triple-boiled
green beans and chicken.

Agricultural Research/March 1998

Special Dietary Guidelines for

Teenage Mothers

here are Recommended
Dietary Allowances, or
RDAs, for teenagers and for
women nursing a baby. But should
there be special nutritional guidelines
for teenage mothers who are nursing?
Some preliminary research suggests it
might be a good idea.
Pediatrician Kathleen Motil, who
is with the ARS Children's Nutrition
Research Center in Houston, Texas,
compared the milk production of 22
mothers-half teens, half adults. The
nutrient compositions were similar,
but the teens produced 37 to 54
percent less milk than adults. Motil's
findings were published last summer
in the Journal of Adolescent Health.
Motil said the differences be-
tween adult and teen milk produc-
tion remained statistically signifi-
cant, even after she adjusted the
data for differences in feeding
time and daily nursing fre-
quency. Why should the milk
volume be different? Motil has
a theory.
"Our preliminary observa-
tions suggest that teenage
mothers are facing a dual
metabolic challenge," said
Motil. "It may be they are
still growing, themselves,
which may cause an extra
nutritional demand."
Motil and her colleagues
wanted to find out more about
teen nutrition during lactation.
They measured body composi-
tion, dietary intakes, and milk
production. The participants:
24 teenage mothers, half of
whom breast-fed their infants.
Eleven additional teens who
had never been pregnant served
as a control group. Barbara
Kertz, patient service coordina-
tor at the nutrition research
center, organized the study.
Preliminary findings suggest
that teenagers who nurse their

infants continue to add muscle mass
to their bodies, indicating ongoing
"We found that nursing teens
consumed more energy (calories),
protein, and vitamin B6 than teen
mothers who bottle-fed or teens who
never had children," says Kertz.
"They were taking in 23 percent
more calories and vitamin B6 and 40
percent more protein." The teens'
intake returned to regular levels after
weaning. This research team also
included nutri-

tionist Corinne Montandon, who
helped the girls keep a food journal to
track the amounts and kinds of foods
they ate. Montandon reviewed the
journals for accuracy and sometimes
provided a little advice. She cautioned
one mother, for example, against
trying to crash diet her way back to a
pre-pregnancy figure.

Encouraging Breast-Feeding
Knowing about teenagers' nutri-
tional demands during breast-feeding
fits into a bigger plan of encouraging
all mothers to breast-feed-regardless
of age. In fact, USDA's Food and
Nutrition Service (FNS) has started a
nationwide campaign to encourage
The number of U.S. teenagers
becoming pregnant has been declin-
ing, but many groups estimate half a
million girls under
20 do give

Sopar Seribuira
(RNi gets to knoi
teen mother
w will
pa te in a
eCamnines l
lactation on thr
young mother's
bod) composition
t- i Au CILLI. ",

Agricultural Research/March 1998

annually. For those who choose to
raise their infants, breast-feeding can
offer advantages such as protection
against a broad range of infections
and enhanced bonding.
Teenagers are less likely to chose
breast-feeding than adults, however.
During an FNS focus group on
breast-feeding, women of all ages
cited embarrassment and lack of
family support as barriers to breast-
But teens face special
problems, according to a
survey by Alain Joffe,
M.D., of the Department I
of Pediatrics at Johns
Hopkins University
Hospital. Joffe has studied
breast-feeding among 250
inner city teens in Baltimore, Mary-
land. Susan Radius, a sociologist at
nearby Towson University, was a co-
The researchers found teenage
mothers who returned to high school
had a hard time working nursing into
their schedule.
Joffe said in his survey the best
indicator of whether a teen would
breast-feed successfully was having a
breast-feeding mentor. That person
could be her mother, aunt, or other
older friend who had breast-fed
successfully and could provide
He added that for teens to accept
breast-feeding they must know the
benefits and feel confident about
ways of dealing with obstacles. Some
high schools, for example, allow new
mothers special time to breast-feed.
Breast-feeding advice and public
acceptance seem a long way from re-
search. But these outside factors can
have very real effects on the science.
If fact, the researchers have to ac-
count for the extent of their teenage
subjects' breast-feeding knowledge.
That's why Kertz, a lactational con-
sultant, met with the girls in their

study from delivery onward, to pro-
vide breast-feeding basics.
Still, the researchers at the Hous-
ton center don't know exactly how
the teens handled their breast-feeding
before their study began. Theresa 0.
Scholl, who is with the University of
Medicine and Dentistry of New
Jersey, read Motil's paper on breast
milk production. Scholl's career has
focused on the effects of teen preg-

nancy and lactation on the health of
girls and their infants.
"The differences between the
growing teens and adult women in
this study are huge. It's really
impressive," says Scholl. "It might
be good to do a follow-up study of
the infants from birth to the first 6
months. That way, you could find out
if the teen mothers were offering to
nurse less often from the start and if
that contributed to a reduction in
milk flow."
Kertz agrees that the study's
findings, like all scientific research,
open the door to new questions.
"Breast-feeding is an issue of
supply and demand," she says. "The
more a mother breast-feeds, the more
milk she'll have and the longer she'll
be able to nurse. Most of the girls
weaned their infants at 3 to 4 months.
Was this an arbitrary decision to stop
nursing, or did the young mothers
lack the nutrients to continue?"
There are bigger questions,
however-the most basic one being
how real is the competition between
growing teens and their infants for
nutrients? Another is: Do the girls
really continue to grow during their

childbearing and nursing? Medical
textbooks once said no; now the
question is being revisited.
Scholl points to her studies of preg-
nant teens that measured growth of the
lower leg only, rather than from head
to foot. Lordosis, a natural bending of
the spine during pregnancy, can cause
errors in a head-to-foot measurement.
These studies suggested strongly that
growth continues during pregnancy.
Does it follow that
continued growth in teens
*could affect breast milk
volume? Scholl points out
that, during pregnancy at
least, nature often favors
the mother during nutrient
stress. Studies on famine
and infant birth weight
have suggested this natural advantage
may have contributed to the survival
of the human species.
"Nature wouldn't allow the mother
to deplete all her resources," says
Scholl. "If it did, she couldn't live to
bear more offspring. Moreover, if the
mother died, what would happen to
her baby?"
More research will need to be done
to say with certainty that teen growth
causes nutrient competition that results
in lower birth weights in newborns
and less milk during lactation. But
Scholl's work on teen births and
Motil's work on teen nursing lend
support to the theory that the body
puts some of its nutrients on reserve to
benefit the teenage mother.
If this proves to be true, physicians
will want to be sure that teenage moth-
ers are getting the extra nutrition they
and their infants need to ensure breast-
feeding success.-By Jill Lee, ARS.
Kathleen Motil is at the USDA-ARS
Children's Nutrition Research Center,
Baylor College of Medicine, 1100
Bates St., Houston, TX 77030; phone
(713) 798-7180, fax (713) 798-7187,
e-mail *

Agricultural Research/March 1998

Vitrification Keeps Pig Embryos Viable

A confocal microscope enables animal physiologist John Dobrinsky (right) and research
associate Charles Long to examine enlarged images of cryopreserved pig embryos on

C consumers want high-quality
food at lower prices, so
producers are scurrying to
meet price and quality demands of
the marketplace. And interest in
foods with enhanced qualities such
as leaner, more tender meat is
forcing livestock producers to look
to science, particularly genetics, for
Fortunately, Agricultural Re-
search Service scientists at the
Germplasm and Gamete Physiology
Laboratory in Beltsville, Maryland,
are helping to meet the challenge.
"In order to produce a better
product for the consumer, we must
develop strategies for maximizing
the genetic potential of our domestic
animals," says John R. Dobrinsky,
an animal physiologist at the lab.
"Maintaining genetic diversity is
the key to maintaining the most
valuable genetic traits in animal

populations that will provide the
foundation for meeting the needs of
future generations," he says.
Dobrinsky and his colleagues are
working to develop technologies for
preserving germplasm and embryos
from today's genetically and eco-
nomically superior animals. They
are developing methods to preserve
pig embryos indefinitely in liquid ni-
trogen at -320oF (-1960C). Preserved
in this way, the embryos' biological
activity all but ceases. After removal
from storage and transplant into a
surrogate mother, the embryos re-
sume normal development.
Since the mid-1980s, the meat
animal industry has been routinely
cryopreserving embryos of several
livestock species, especially cattle.
However, the $11 billion a year
swine industry has not had this
technology available. Now that
could change.

Scientists at the Beltsville lab are
using a technique they call vitrifica-
tion. They cool a liquid medium so
fast that ice crystals can't form and
then store pig embryos in it. For a
solution to vitrify, it must be instan-
taneously cooled in liquid nitrogen.
Rapid cooling prevents ice
crystals from forming in or around
the embryos, and this is key to their
safe storage and later development,
Dobrinsky says. "Pig embryos are
extremely sensitive to slow cooling
below normal room temperatures-
about 59"F (15"C). This type of slow
cooling is required during conven-
tional embryo freezing methods, and
this is why pig embryo survival after
cooling or cryopreservation has been
so poor," says Dobrinsky.
The problem, he explains, is that
embryos suffer physiological and
structural changes when going from
normal body temperatures to cooler
temperatures. "Hypothermic condi-
tions can change normal cell func-
tion and skeletal structure, making
the embryo incapable of normal
Rapid cooling during vitrification
is thought to outrace damaging
effects evident during slow cooling.
With vitrification, Dobrinsky and his
colleagues achieved modest success
rates-that is, about 40 percent of
the embryos survived. But that was
not good enough.
Dobrinsky wanted to know
exactly how the embryos' cell
structures were being damaged
during cryopreservation. "We
focused on the embryonic cytoskele-
ton," he says. The cytoskeleton is a
network of microfilaments and
microtubules that gives embryonic
cells their shape and support-just as
the human skeleton shapes and
supports the body.
With a confocal microscope,
which uses lasers, Dobrinsky took a
closer look inside embryos during

Agricultural Research/March 1998

and after cryopreservation. The
microscope produces a digital recon-
struction of all cells in the embryo.
"We could see the cell plasma
membranes, and the microfilaments
were being disrupted. We wanted to
prevent these membrane disruptions,"
he says.
"Our hypothesis was this: If we
dismantled the microfilaments in an
orderly way before cryopreservation,
they might reform normally and
support the plasma membrane after
cryopreservation. To do this," says
Dobrinsky, "we placed from 10 to 20
embryos into small straws in a
solution containing a compound
called a microfilament inhibitor. We
vitrified and stored those straws in a
sealed canister filled with liquid
"We learned that they can be
stored this way indefinitely," he says.
"And once they are warmed, the
embryos can then be further cultured
or transferred to surrogate mothers,
where the microfilament network will
reform and normal cell development
will resume."
Dobrinsky has found his system
increases the survival rate to more
than 80 percent in the laboratory.
"From the laboratory to the barn,
we warmed vitrified embryos and
transferred them to surrogate moth-
ers, producing the first live offspring
from vitrified/warmed pig embry-
os," says Dobrinsky. "This is a
first for maternal genetics. Until
now, the swine industry could only
preserve sperm from select males
through semen cryopreservation-
processes that were developed at
Beltsville in the 1970s."
This high-tech cryopreservation
approach is more than just a
scientific advancement: Both
swine producers and consumers
will benefit. It could bring a major
increase in the efficiency of 3
making pigs with important a

Cryopreserved pig embryos can be stored
indefinitely inside special straws
submerged in liquid nitrogen.

genetic traits available to breeders
worldwide. Today, many pigs are
transported by air freight from
countries with breeder herds to those
where new breeding herds are being
"The chance for global expansion
of the swine industry is another
potential advantage," says Dobrin-
sky. "Keeping separate breeding
herds would be costly for producers.
This technology will allow us to

nis sow's lve pigs aevelopea irom cryopreservea
nd surgically transferred embryos.

import and export valuable breeding
stocks and unique germplasm-
without the worry of shipping live
animals. It has the potential for
changing the way we produce future
generations by minimizing risk of
disease transmission or loss of
valuable animals during transport."
Costs of caring for breeding herds
and transporting animals are ex-
tremely high, because of health tests
and other requirements. Shipping
embryos could considerably reduce
these costs and associated con-
straints, since embryos cost very
little to maintain while in liquid
nitrogen storage.
Embryo cryopreservation also
allows easier regeneration of existing
genetic lines or expansion of new
ones. Should a disease or catastrophe
wipe out an entire herd of superior or
valuable pigs, a producer could
regenerate a reproducing herd within
2 years.
What does this mean for the
"It will enable production of the
most genetically superior swine stock
that our technology and science will
allow, ensuring a safe, wholesome,
and healthy pork product for the
consumer at reduced costs," says
Dobrinsky. "We will also have
permanent stocks of genetically
superior animals to meet future
consumer demands. This technolo-
gy could revolutionize the swine
industry by opening global sources
of genetic stocks."-By Tara
Weaver, ARS.
John R. Dobrinsky is at the
USDA-ARS Germplasm and
Gamete Physiology Laboratory,
Bldg. 200, 10300 Baltimore Ave.,
Beltsville, MD 20705-2350; phone
(301) 504-8134, fax (301) 504-
5123, e-mail *

Agricultural Research/March 1998

Compression Puts the Squeeze on Hay Pests

T lightly compressed bales of
freshly harvested hay
destined for dairy cows,
beef cattle, or racehorses in Japan
can now move swiftly through
agricultural inspections there, thanks
to studies by Agricultural Research
Service scientists. U.S. growers
export about $240 million worth of
hay to Japan every year.
Tests conducted for the past 6
years by entomologist Victoria Y.
Yokoyama with ARS at Fresno,
California, showed that compressing
standard bales, then fumigating them
with hydrogen phosphide for 7
days at 680F, kills any Hessian BRI,
flies that might be hiding inside.
Japan has recently approved
this safe, practical quarantine
procedure, ensuring that Hes-
sian fly can't sneak into the
country in baled hay. The new
procedure applies to compressed
bales of American-grown
timothy, alfalfa, oat, bermuda-
grass, and sudangrass.
In the past, any unfumigated
compressed bales with even a
wisp of wheat-a Hessian fly
favorite-or perhaps a stray
stem of a weed species known
to harbor the fly-would be
rejected by Japanese agricultural
inspectors to safeguard Japan's
farms from this pest. Inspectors
could send back-at the Ameri-
can shipper's expense-the
entire container load.
Hessian fly is one of the
worst insect enemies of wheat.
It's believed the pesky insect
hitchhiked to North America
during the Revolutionary War, E
traveling inside straw mattresses co
used by Hessian mercenaries.
Yokoyama's tests with West
Coast hay were the first to show that

merely compressing the bales at
1,136 pounds of pressure per square
inch killed a large proportion of the
test insects concealed within the
bales. For her experiments, Yokoya-
ma and colleagues reared more than
630,000 Hessian flies. She did the
work with Gina T. Miller and
Preston L. Hartsell (now retired) at
Fresno and Jim H. Hatchett, an ARS
entomologist at Manhattan, Kansas.
Hydrogen phosphide fumigation
provides an extra measure of pest
control. The fumigation takes place
inside cargo containers, after which

itomologist Victoria Yokoyama (left) and technician
na Miller inspect wheat used to rear Hessian flies for
impressed hay experiments.

American agricultural inspectors
affix a sticker indicating that the
containers' contents have been
properly treated. Compressed bales
shipped in containers that don't bear
this "phytosanitary" certification are
subject to time-consuming dockside
inspections in Japan and run a high
risk of rejection.
The idea of fumigating bales to
rid them of insect stowaways is not
new. Work at Manhattan by Hatchett
and Charles L. Storey (now retired),
for example, won Japan's approval
in 1978 for phosphine fumigation of
standard-size timothy hay bales.
But Yokoyama's tests are the
First to provide the extensive
documentation needed to garner
Japan's okay of a combined
compression and fumigation
technique for the increasingly
popular compressed bales.
Only one-third the size of
conventional bales, compressed
bales are neat, compact, and
easier to handle. They save
storage and shipping costs
because more of them can be
squeezed into a barn, ware-
house, or shipping container.
The National Hay Associa-
tion, California Department of
Food and Agriculture, and the
Organization of Kittitas County
Timothy Hay Growers and
Shippers in Washington helped
fund Yokoyama's research.-
By Marcia Wood, ARS.
Victoria Y. Yokoyama is in
the USDA-ARS Commodity
Protection and Quarantine
Insect Research Unit, Horticul-
tural Crops Research Laborato-
ry, 2021 S. Peach Ave., Fresno,
CA 93727; phone (209) 453-
3026, fax (209) 453-3126, e-mail *

Agricultural Research/March 1998

Tackling Ticks That Spread

Lyme Disease

Adult deer tick, Ixodes
scapularis. About 5x.

I f just thinking about ticks
makes you squeamish, then
you'll want to stay away from
Dolores Hill's lab in Beltsville,
Maryland. There, in tiny glass vials
and Styrofoam containers, Hill keeps
several hundred blacklegged deer
ticks, scientifically known as Ixodes
A parasitologist for USDA's
Agricultural Research Service, Hill
collects the blood-sucking ticks as
part of a 5-year project to biologically
control the pests with microscopic
roundworms, called nematodes.
Hill's goal is to formulate the
worms into a product that could be
sprayed in residential areas, like
backyards, where homeowners can be
bitten by ticks infected with Borrelia
burgdorferi, the bacterium that causes
Lyme disease. In 1996, the Centers
for Disease Control in Atlanta,
Georgia, received more than 16,000
reports of the tickborne disease.
Ninety percent came from the north-

Chemist Patricia Allen examines a fungal
isolate before applying it to a live tick, to
see if it can penetrate the tick's outer

eastern United States, where I.
scapularis is most prevalent.
Humans aren't the tick's first
choice of hosts. But suburban sprawl
into wooded habitat has placed
people in closer contact with white-
tailed deer, the adult ticks' natural
host and chief transportation source.
"If deer are feeding on azalea
bushes at the back of your yard,
that's where a female tick may drop
off and lay her eggs. So that's also
where you'd want to spray the
nematodes," explains Hill, who is
with the ARS Parasite Biology and
Epidemiology Laboratory.
Her top tick-fighting recruits
include nine strains of the nematode
species Steinernema and four strains
of Heterorhabditis. Both are well
known to science, she says. While
harmless to higher vertebrates
(humans and livestock, for instance),
the nematodes are renowned for
attacking many insects pests.
"But few people have really
looked closely at whether these
nematodes will infect and kill ticks,"
says Hill. Ticks aren't insects, but
arachnids-like mites, scorpions,
and spiders.
Her studies show the worms may
be most effective against adult
female ticks, which lay as many
2,000 eggs. "If you find an engorged
adult deer tick on you," says Hill,
"it's most likely a female taking a
blood meal so she can reproduce."
But tiny tick offspring are as
much of a menace as grown adults.
This is especially true of the
nymphs, a juvenile stage about the
size of a pepper flake. They are
more likely than adult ticks to
transmit Lyme disease to humans,
says Hill. Their tiny size allows
nymphs to feed longer without being
detected, giving them enough time
to pass the Lyme bacterium into
their host's bloodstream.

One tick-fighting strategy is to
spray an infested area with an
appropriate insecticide or acaricide.
"But many people don't want to
have those chemicals sprayed in
their backyards," notes Hill.
Many of the tick-killing chemi-
cals are toxic, and their use may
have adverse environmental effects.
They may also require repeat
applications as new ticks are brought
in by deer and other animals search-
ing for food.
The nematodes could offer the
advantage of sticking around longer,
taking up residence in soil, leaf
litter, or other places ticks seek
shelter. "This may offer a new way
of controlling these tick populations
without affecting the environment,"
says Hill.
Her approach targets adult female
ticks, to curb the size of the next
generation of offspring. "We've
studied nymphs, larvae, flat (unfed)

In an isolated test plot seeded with
engorged adult female ticks, parasitologist
Dolores Hill sprays infective juvenile
Steinernema nematodes as a biological

Agricultural Research/March 1998

adult ticks, and engorged (fed)
females," says Hill. "So far, the only
stage that is susceptible to the
nematodes is the engorged adult

Getting the Wherewithal for
For her research, Hill must first
rear large numbers of the nematodes
inside the bodies of greater wax
moth larvae. She keeps these host
insects in a sealed plastic container
with oatmeal and other high-fiber
cereals for food.
To extract the worms, researchers
place the infected larvae in two petri
dishes-one inside the other. After
feeding inside their hosts, the worms
crawl out of the larvae into the first
petri dish and then into the second,
which is filled with water. Hill then
drains the water into another contain-
er and stores it at room temperature.
To test their ability to infect ticks,
Hill adds either 500, 1,000, or 1,500
of the test nematodes to a petri dish
containing five ticks. She uses the
procedure with each tick growth
Her tests show that adult females
that have fed on blood are most
vulnerable to nematode attack because
feeding expands natural body open-
ings. And the nematodes aren't picky
about where they enter: It can be the
tick's breathing holes spiracless),
mouth, anus, or genital pore.
The Steinernema nematodes, more
so than the Heterorhabditis, rely on
these openings. The latter species
sports a short, sharp tooth it can use
to gnaw through a tick's hard outer
cuticle. This may give the toothy
worm a slight advantage over
Steinernema--especially in trying to
penetrate the flat bodies of unfed
Hill has viewed Steinernema's
unsuccessful attempts under a

microscope. The unfed ticks, she
says, "bat away the nematodes that
are trying to get into them."
But engorged female ticks aren't
so lucky. Once infected, death comes
quickly. "Less than 50 nematodes
will cause the death of fed females in
24 hours," notes Hill.
Interestingly, it's not the worms
that kill the ticks. Rather, it's a
species of symbiotic bacteria of the
genus Xenorhabdus that the nema-
todes carry in their gut. Once inside
a tick, the worms release the bacte-
ria, which in turn liquefy the tick's
fat bodies and other tissues.
The nematodes then feed on this
nutritious soup and mate, giving rise
to tens of thousands of offspring,
called infective juveniles. Once the
nutrition source is exhausted, these
juveniles leave the tick's body in
search of a new host to infect.
Though successful in the lab, the
true test of the nematodes' tick-

killing prowess will come with
outdoor studies. Hill is now planning
several small experiments to that end
at ARS' Beltsville (Maryland)
Agricultural Research Center. Such
tests will help in compiling data on
where, when, and how best to apply
the nematodes-and at what concen-
She also hopes to identify cold-
hardy strains that can withstand
fluctuating temperatures that charac-
terize much of the East's fall, winter,
and spring months. "Female ticks are
abundant in the late fall and early
spring," she says, "so you want to
have nematodes capable of with-
standing temperature extremes at
those times of the year."

Plotting a Fungal Demise
Hill's colleague, ARS chemist
Patricia C. Allen, is pursuing another
form of biological tick control. Her
approach calls on naturally occurring

Entomologist John Carroll sweeps grass and brush areas for adult ticks to use in laboratory

Agricultural Research/March 1998

fungi that infect adult ticks-as well
as nymphs, larvae, and eggs. Allen
has already isolated several fungi
from ticks that have died of natural
causes in the Beltsville area and
nearby Patuxent Wildlife Center.
Allen tests each new fungal isolate
for production of a protease enzyme.
This protein-degrading enzyme is
essential to a fungus' penetration of a
tick's outer protective cuticle.
To test the infectivity of a promis-
ing candidate fungus, the researcher
dips healthy, live ticks into a prepara-
tion containing 100,000 to
1,000,000,000 fungal spores. She may
also place the ticks in small plastic
tubes with spore-treated paper wedges
at the bottom. She maintains the tubes
at room temperature with 100 percent
humidity and observes the ticks daily
for signs of fungal activity.
Allen and ARS colleague Gary
Samuels have tentatively identified
one of the most promising fungi as
Gliocladium roseum. In one experi-
ment, the microbe killed 70 percent of
unfed ticks, compared to 100 percent
killed by a well-known fungus-
Metarhizium anisopliae-that Allen
uses in her studies as a kind of
benchmark to help gauge the infectiv-
ity of new isolates. Her research lays
the groundwork for building an
arsenal of tick-fighting microbes that
could perhaps be deployed under
varying environmental conditions.
"The ultimate aim of this research,
however," says Allen, "is to develop a
practical method of applying patho-
genic fungi to the Lyme disease tick."
One possibility is to formulate
fungal spores into a preparation that
could be sprayed onto leaf litter,
shrubs, or other vegetation where
ticks wait for a passing host.
But first, says Allen, any new
fungus with biocontrol potential
would have to undergo toxicity tests
to ensure human, animal, and environ-
mental safety.

On another front, deer could bring
ticks to their doom in a new, ARS-led
experiment to fight Lyme disease.
ARS and collaborating university
scientists began the 5-year, USDA
Northeast Regional Tick Control
Project last fall at test sites in Con-
necticut, Rhode Island, New York,
and New Jersey. Maryland's partici-
pation in the project begins this
spring, says entomologist John F.
Carroll of ARS' Parasite Biology and
Epidemiology Laboratory in
Carroll will coordinate the installa-
tion and use of 25 experimental deer-
feeding stations on a 2-square-mile


Fungi grown on petri dishes were taken
from ticks assumed to have died in nature
from the fungi. The isolate on the right is
Metarhizium anisopliae, the bottom one is
Gliocladium roseum, and the other two are
unknown pathogens.

test site along Maryland's Baltimore-
Washington corridor. The site will
include residential areas, says Carroll,
"because they typify situations where
people are at risk of Lyme disease."
The stations, called four-posters,
treat deer with amitraz, a chemical
that kills ticks but doesn't harm the
animals. Each station has a bin of
corn and four upright rollers coated
with amitraz. To get to the corn, deer
must brush their head, neck, and ears
against one of the rollers at the
station's four corners.

ARS entomologist Mat Pound,
engineer Allen Miller, and biological
lab technician Craig LeMeilleur
developed, tested, and patented the
four-poster technology. They are at
ARS' Knipling-Bushland U.S. Live-
stock Insects Research Laboratory in
Kerrville, Texas.
In studies there, use of the four-
posters controlled up to 97 percent of
lone star ticks, which plague cattle
and humans. [See "Ticked Off!" Agri-
cultural Research, April 1994, p. 4.]
Carroll and other scientists partici-
pating in the Northeast project hope
for similar success against 1. scapu-
laris. The project's goal: to reduce up
to 90 percent of the tick population,
especially nymphs, at each state's test
site by August 2000.
Despite the use of insecticides,
repellents, protective clothing, and
other measures, blacklegged deer ticks
continue to pose a serious public
health concern-particularly in
midwestern and northeastern states.
Hiking, hunting, and other outdoor
recreational activities during spring
and summer months also place
humans at greater risk of contracting
Lyme disease from infected nymphs.
"The nymphs are out there at a time
when people are engaged in activities
that heighten their risk of exposure to
ticks," says Carroll.
If the Northeast project is success-
ful, the scientists will transfer the
four-poster technology to public
health officials, pest control experts,
and others in Lyme-plagued commu-
nities.-By Jan Suszkiw, ARS.
Dolores E. Hill, Patricia C. Allen,
and John F. Carroll are at the USDA-
ARS Parasite Biology and Epidemiol-
ogy Laboratory, Bldg. 1040, 10300
Baltimore Ave., Beltsville, MD 20705-
2350; phone (301) 504-8300, fax
(301) 504-5306, e-mail *

Agricultural Research/March 1998

A micro-
saboteur may
deprive corn
earworms of their
greatest pleas-
ure-feasting on
corn plants at
farmers' expense.
The saboteur is
a natural insect
pathogen called a
baculovirus. In
nature, the virus
infects the ear- corn
worm in order to ea w- lav
multiply and ( d '
spread. But the o |'
pest may not die lered
right away, buv
instead continuing i a m
to chew on plants,
says Ashok K.
An entomolo-
gist with the
Research Ser- EniomologiIs
vice's Insect -shok Raina
Biocontrol Labo- places corn
fearu~orni larwae
ratory in Belts- on a tornato
ville, Maryland, plant alter
Raina's solution is It-eding Iheni
tor 48 hours on
to genetically alter a diel including
the baculovirus so a recombinant
it overwhelms the haculo iru-.
earworm with an
overdose of an
appetite-stopping hormone
In the South, crop-htmIngr corn
earworms cost farmer, ain cir.uttedL
$1.5 billion annually in los-e, and
chemical controls. S\\eet corn
growers loathe this pc't and ma\
spray up to 20 times a ,.ason Itc
ensure unblemished Cars But this
can endanger the enx ironmnent and
beneficial insects.
Raina's approach should letter a
safer alternative. For one. the

baculovirus dooms
the earworm from
within. And outside
the insect, the virus
eventually breaks
down under the
sun's ultraviolet
light. It's also
harmless to hu-
mans, livestock,
and plants.
The hormone,
called helicokinin-
II (Hez-HK-II),
actually comes
from the corn
earworm, not from
the baculovirus.
Raina discovered it
in earlier studies of
the pest's nervous
system. He later
pinpointed the
S specific gene
responsible for
Making the hor-
mone, cloned it,
and inserted it into
the baculovirus. He
has filed for a
Patent on the gene.
In its natural
owner--the corn
earworm-the Hez-
HK-II hormone
helps regulate
procese,. enabling the insect to
gro\ fromni caterpillar to adult moth.
But Raina showed that inserting the
He -HK-II Lene into the virus and
then teedil ng or injecting the altered
iruL into [the earworm leads to
hormonal sabotage.
Once ine4eted, the virus quickly
replicate inside the earworm's gut
cell In the process, it churns out
the Hez-HK-lI hormone, adding to
that tlreuid\ present.

Agricultural Research/March 1998

"The hormone is naturally present
in the insect, but only at certain
times," Raina explains. "Here, we're
flooding the insect with it." As a
result, the pest soon stops eating and
excretes much of its water.
But why not just spray the hor-
mone directly onto plants?
Because, says Raina, the hormone
is made of a type of small protein
called a peptide. Peptides are expen-
sive to produce, and they degrade
quickly. Also, you can't spray them
onto a crop like you do an insecti-
cide, and they don't penetrate the
But the baculovirus can get inside
the earworm, making it an ideal
delivery mechanism for the peptide
hormone. Also, the technology exists
for growing baculoviruses in special
industrial vats. This could expedite
the virus' development as a biopesti-
cide product that growers could
spray onto crops.
In lab studies, at a temperature of
23C, hatchling corn earworms
infected with the virus typically
stopped eating after about 48 hours.
By 20 days, only 3 percent had
survived and pupated-compared to
100 percent of the virus-free worms.
The true test will come with field
trials, Raina notes. There, the altered
baculovirus will face wild corn
earworms, which are more robust
than those kept in captivity.
Raina is now conducting green-
house experiments. "Within 6
months to a year," he says, "we
should be able to pass the technology
on to a commercial company inter-
ested in pursuing field studies."-By
Jan Suszkiw, ARS.
Ashok K. Raina is at the USDA-
ARS Insect Biocontrol Laboratory,
Bldg. 467, 10300 Baltimore Ave.,
Beltsville, MD 20705-2350; phone
(301) 504-9296, fax (301) 504-8190,
e-mail *

Insect Salivary Proteins Prevent Blood Clotting

Every summer, both people and livestock face pesky mosquitoes, gnats, and
other biting flies.
The resultant itching and discomfort come from the immune system reacting
to proteins in the insects' salivary glands. These proteins help victims' blood to
flow so the insects can feed easier. They may also aid the transmission of
insect-borne pathogens that can cause diseases.
Scientists at the ARS Arthropod-borne Animal Diseases Research Labora-
tory in Laramie, Wyoming, have identified several such proteins in a small
biting midge called Culicoides variipennis.
This pest is the principal carrier of the viruses that cause bluetongue in
North American cattle. When an infected midge feeds, it can simultaneously
release the viruses into the animal's bloodstream. Bluetongue costs $100
million in lost trade annually, because countries without the disease won't
accept some U.S. livestock exports.
ARS entomologists Walter J. Tabachnick and Adalberto Perez de Leon have
found that the midges secrete several proteins during feeding.
"Some of the proteins cause blood vessel dilation, another acts as an anti-
clotting agent, and one inhibits blood platelets from aggregating and helping in
clotting," Tabachnick says.
Still other salivary proteins inhibit pathogen-fighting cells like macrophages
and lymphocytes, weakening an animal's ability to fight off the viruses. "The
insect creates a very conducive environment in the host," says Tabachnick.
The next step, he says, is to develop vaccines against these insect proteins,
to reduce the spread of bluetongue viruses.
Surprisingly, though, there may also be some beneficial uses for the pro-
teins. "We see great potential that these proteins might serve as pharmaceuti-
cals for humans and livestock-such as anticlotting factors, vasodilators to
widen blood vessels, or immunosuppressives to depress natural immune
responses," says Tabachnick.
The researchers are also studying the role of insect salivary gland proteins
from biting flies in spreading another important livestock disease, vesicular
stomatitis. Preliminary results indicate that, like the midges, other biting flies
release substances into an animal's blood that reduce its ability to fight off the
disease-causing virus.-By Dennis Senft, formerly with ARS.
Walter J. Tabachnick and Adalberto Perez de Leon are at the USDA-ARS
Arthropod-borne Animal Diseases Research Laboratory, P.O. Box 3965,
University Station, Laramie, WY 82071-3945; phone (307) 766-3600, fax (307)
766-3500, e-mail *

Agricultural Research/March 1998

Spice May Be Nice for Controlling
a Chicken Parasite
Adding oil or spice to chick diets can
help stave off parasites that cause
coccidiosis. The disease costs U.S.
poultry producers $350 million a year
in losses and antibiotics. One-celled
Eimeria protozoa cause the disease.
They infect a chick's intestines and
cause lesions that hamper the bird's
ability to absorb nutrients-slowing
its growth or killing it. New
alternatives for Eimeria control are
needed. The microbe is becoming
resistant to available drugs, and
developing new drugs is costly. As
new, natural feed additives, ARS
researchers have tested high-fatty-
acid oils from flaxseed and linseed
plants. The oils don't kill Eimeria.
They trigger oxidative stress, a
natural, biochemical response in
chicks. The stress results in byproduct
compounds that doom Eimeria hiding
in the cecum, part of the bird's small
intestine. Mixed into commercial feed
given to newborn chicks for 4 weeks,
flaxseed oil cut by 54 percent the
number of cecal lesions caused by E.
tenella. Linseed oil in the diet
reduced lesions 64 percent. Also of
interest: cucurmin, an antioxidant
from turmeric, a cooking spice in
curries and other foods. The cucurmin
targets protozoa in the mid-gut.
Compared to untreated birds,
turmeric-fed chicks had 58 percent
fewer lesions from E. maxima and
weighed 35 percent more. E. tenella
and E. maxima are two of seven
Eimeria species researchers hope to
fight with the new strategy. Patricia
Allen, USDA-ARS Parasite Biology
and Epidemiology Laboratory,
Beltsville, Maryland; phone (301)
504-8772, e-mail
pallen @ggpl.

Microscopic Ally Fights Fruit Rot
Grapefruit, oranges, lemons, and
limes could get a new ally to resist
microbes. Scientists with ARS and
Texas A&M University have discov-
ered and patented a beneficial fungus
that fought green mold on citrus in
lab tests. The easy-to-grow fungus
might someday reduce or eliminate
the need for certain postharvest
fungicides. It's a beneficial strain of
Geotrichum candidum. In nature,
wild or virulent G. candidum causes
a fruit disease called sour rot. Dip-
ping, spraying, or dusting fruit with a
beneficial microbe is not a new anti-
rot strategy. But ARS and Texas
A&M researchers were first to
discover and test the avirulent G.
candidum. They suspect it could
protect fruits other than citrus, such
as apples, pears, and strawberries.
Cynthia C. Eayre, USDA-ARS
Horticultural Crops Research
Laboratory, Fresno, California;
phone (209) 453-3162, e-mail

often related, culprits are at work:
infections spread by inadequate water
and sewer sanitation. Poor sanitation
facilities can spread flu and bacterial
and other infections that alone may
reduce transferring. The finding comes
from a joint study by the ARS-funded
Children's Nutrition Research Center
and the University of the West Indies
in Jamaica. The scientists examined
infected and severely malnourished
children at the university's Tropical
Metabolism Research Unit in King-
ston, Jamaica. The finding is impor-
tant for agencies serving America's
poor, as well as for international
relief agencies. Many children suffer
from protein-energy malnutrition, or
PEM. They get enough calories to
survive, but their diets are low in
protein. Infections can reduce the
appetites of these children. And some
of the calories they consume are used
to fight infection rather than support
growth and well-being. As repeated,
undiagnosed infections use up the
child's stored nutrients, he or she
may develop classic hunger symp-
toms-including low transferring. But
according to the researchers, transfer-
rin levels now used are not a good
indicator of protein nutritional status.
Farook Jahoor, USDA-ARS Children
Nutrition Research Center, Houston,
Texas; phone (713) 798-7084, e-mail
fjahoor@ bcm. tmc. edu/

Grapefruit infected with green mold.

Low Blood Protein May Mean
Infection, Not Malnutrition
Doctors generally interpret a low
level of transferring, a blood protein,
to mean a child or elderly person
suffers from malnutrition. Recent
findings suggest different, though

Agricultural Research/March 1998

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