USDA

Read the magazine story to find out more.

ARS scientists are looking for a way to inhibit microbial growth in cotton socks, T-shirts and other clothes using silver particles ranging from 2 to 6 nanometers in size. Click the image for more information about it.

• Nanotech cotton opens up new possibilities for the fiber-and its fans
   
• Cotton's potential for padding nonwovens
   
• Cotton: a body armor for wounds?

New Treatments Could Reduce Odors in Cotton Fabric By Jan Suszkiw
May 10, 2012

Socks, T-shirts and other garments could become less hospitable to odor-causing bacteria, thanks to new antimicrobial treatments being investigated by U.S. Department of Agriculture (USDA) scientists in New Orleans, La.

In studies at the Southern Regional Research Center operated there by USDA's Agricultural Research Service (ARS), a team of scientists is seeking to inhibit microbial growth in cotton using silver particles ranging from 2 to 6 nanometers in size. ARS is USDA's chief intramural scientific research agency.

Silver nanoparticles have been used previously as antimicrobial agents in products, including clothes, plastic food containers and medical textiles. However, the synthetic methods of producing them have relied on the use of toxic agents and organic solvents, according to ARS team leader Brian Condon.

As an environmentally friendly alternative, his team showed that polyethylene glycol and water worked just as well in generating the silver particles. Moreover, the particles were of the desired size, reported Condon, ARS engineer Sunghyun Nam, and former ARS researcher Dharnidhar Parikh, in a recent issue of the Journal of Nanoparticle Research.

The researchers also devised a method of prompting silver nanoparticles to form directly on cotton fibers, eliminating the handling and storage of the antimicrobial agents prior to application. This should give cotton an advantage over synthetic fabrics, which have not been amendable to silver nanoparticle treatment, notes Condon, who leads the ARS center's Cotton Chemistry and Utilization Research Unit.

In another approach, ARS chemist Vince Edwards, together with Condon, developed a treatment for impregnating nonwoven cotton fabrics with lysozyme, an enzyme that slices open the cell walls of microorganisms, killing them—including those that cause odor or infection. Similar enzymes also have potential use in biodefense applications, such as deactivating nerve agents, adds Condon.

The researchers are seeking commercial partners to help usher the advances into the marketplace, all with an eye towards assuring the viability of American cotton at a time of increasing production costs, dwindling resources and global competition.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

ARS scientists have developed a system using DNA "barcodes" to identify emerging biotypes of Russian wheat aphids, an insect pest that does more than $200 million in damage annually to wheat and other cereal crops in the United States. Click the image for more information about it.

• No mistaking this bug with new insect ID technique
   
• ARS preserves plants and animals for future needs
   
• New barley is bad news for Russian wheat aphids

New Tool for Tracking a Voracious Pest By Dennis O'Brien
May 8, 2012

Since it first appeared in Texas in 1986, the Russian wheat aphid has cost U.S. wheat growers an estimated $200 million each year. But U.S. Department of Agriculture (USDA) scientists have developed a new tool to keep track of this nasty worldwide threat to wheat and barley and to provide guidance to researchers and plant breeders on control strategies.

Gary Puterka, who is with the Agricultural Research Service (ARS) Wheat, Peanut and Other Field Crops Research Unit in Stillwater, Okla., and his colleagues have developed a system that uses DNA "barcodes" to identify emerging biotypes of Russian wheat aphids that threaten wheat and other cereal crops. In DNA barcoding, scientists sequence a designated part of an organism's genome and produce a barcode from it for a systematic comparison with the sequenced DNA of other closely related species.

ARS is USDA's chief intramural scientific research agency, and this research supports the USDA goal of promoting agricultural sustainability.

Russian wheat aphids have been controlled by resistant wheat varieties, but the appearance of a new biotype that overcame resistance in 2003 has forced growers to rely on insecticides while breeders develop new, resistant varieties. Monitoring of Russian wheat aphid populations for the emergence of new biotypes is important because researchers and breeders need to know resistant crops being developed will be effective against emerging biotypes.

Aphid species typically produce eggs in the fall and place them in wheat and wild grass leaves. The eggs of various aphid species are often placed together and that makes locating new biotypes difficult. Puterka and Kevin Shufran, a former ARS scientist who recently retired from the Stillwater unit, have developed a way to tell them apart.

The researchers extracted DNA from the eggs of 10 previously identified species of aphids, including several of the Russian wheat aphid's closest relatives, and sequenced a variable part of the CO1 mitochondrial gene. In a blind experiment, Shufran compared DNA from eggs of species provided by Puterka, who masked their identities. Through genetic analyses, Shufran was able to DNA barcode the different aphid species. This will greatly improve their effort in locating new biotypes. Results were published in Annals of the Entomological Society of America.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

ARS is studying a potential biological control for the kudzu bug, which does feed on the kudzu vine, but also could be a major pest of soybeans, peanuts and other legumes. Click the image for more information about it.

• Overseas lab seeks U.S. weed control "recruits"
   
• Trap would help keep stink bugs outdoors
  

Biocontrol Agent Tested to Battle Invasive Kudzu Bug By Jan Suszkiw
May 3, 2012

Don't let its common name fool you: The "kudzu bug" isn't to be trusted.

Sure, it will feed voraciously on the stems of kudzu, the "Vine That Ate the South." But Megacopta cribraria also has a taste for legumes, including soybeans. And in Georgia, where this native of Asia was first discovered in October 2009, there's worry the pest will infest peanuts, endangering the state's $2-billion legume crop.

U.S. Department of Agriculture (USDA) scientists and their collaborators haven't been idle, however. At the Agricultural Research Service (ARS) Stoneville Research Quarantine Facility in Stoneville, Miss., entomologist Walker Jones is evaluating a top natural enemy of the bug, the parasitic wasp Paratelenomus saccharalis. ARS is USDA's principal intramural scientific research agency.

The wasp is nonstinging and harmless to humans, pets and other animals. However, it lays its eggs in those of Megacopta's. Upon hatching, the wasp's maggot-like brood devour the pest's own developing embryos, reducing the size of the next generation.

Megacopta belongs to a unique insect family that doesn't occur anywhere in the Americas. Thus, importing its co-evolved natural enemies isn't expected to endanger native U.S. bug species, explains Walker, who leads the ARS Biological Control of Pests Research Unit in Stoneville. First, however, the wasp must pass muster on a long list of requirements to confirm its host specificity and environmental safety, starting with the quarantine trials.

Toward that end, Walker is screening eggs of native species of related bugs to learn whether the wasp will attack them, and so far it hasn't. The evaluations require a steady supply of bugs representing four families and 15 species sent to Walker by collaborators across the country.

Besides Georgia, Megacopta has also been reported in parts of Alabama, Tennessee, North Carolina, South Carolina and Virginia. A university-led effort is tracking the pest's spread and studying its basic biology, host crop range, economic impact, chemical control and vulnerability to native predators, parasites and pathogens.

Read more about this research in the May/June 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

ARS entomologist Matt Greenstone is using the Colorado potato beetle's barcoded DNA to determine how effective different predator insects are at controlling it. Click the image for more information about it.

• No mistaking this bug with new insect ID technique
   
• Threat to grapevines and gardens now easier to pinpoint
   
• Bacterium curbs several insect pests

Barcoding Insects as a Way to Track and Control Them By Dennis O'Brien
April 30, 2012

Barcodes may bring to mind the sales tags and scanners found in supermarkets and other stores. But U.S. Department of Agriculture (USDA) scientists are using "DNA barcodes" to monitor insects that damage crops as diverse as wheat, barley and potatoes, and to make pest management decisions.

In DNA barcoding, scientists sequence a designated part of an organism's genome and produce a barcode from it for a systematic comparison with the sequenced DNA of other closely related species. DNA barcodes are being developed on a wide range of plants and animals as part of a global effort to catalogue the diversity of life on Earth.

Matthew Greenstone, an Agricultural Research Service (ARS) entomologist at the agency's Invasive Insect Biocontrol and Behavior Laboratory in Beltsville, Md., is using DNA barcodes in an unconventional way: to identify insect predators best equipped to control the Colorado potato beetle, which is the single most damaging insect pest of potatoes in the Eastern United States.

ARS is USDA's chief intramural scientific research agency, and this research supports the USDA goal of promoting agricultural sustainability.

Numerous studies have analyzed the gut contents of predatory insects to evaluate their ability to control pests in a field. But predators digest prey at different rates, so simple gut analysis is insufficient for accurately comparing the effectiveness of different predators. Greenstone has fine-tuned the approach, using barcodes to come up with a way to factor in how quickly different insects digest prey.

He and his colleagues collected four potato beetle predators, fed them lab-raised potato beetles and determined how long the pest's barcoded DNA could be detected in the predators' guts. The results, published in the journal Entomologia Experimentalis et Applicata, show the importance of taking digestive rates into account when evaluating insect predators as biocontrol agents. They also may provide guidance to growers on the most effective control strategies for combating a voracious pest.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

ARS researchers are looking at phytochemical differences between green tea, brewed from leaves, and green tea dietary supplements. Photo courtesy of Microsoft clip art.

• Better analysis methods for vitamin D
   
• Data on food antioxidants aid research
   
• A food's composition, by any preparation method, is not the same

Analyzing Green Tea Leaves and Supplements By Rosalie Marion Bliss
April 27, 2012

Quality control is a key factor in making sure green tea dietary supplement products pack the same antioxidant punch as green tea leaves used for brewing beverages, according to U.S. Department of Agriculture (USDA) scientists.

Green tea-based dietary supplements have gained popularity in the U.S. market in recent years. But when it comes to sipping green tea versus taking the dietary supplement form, the better choice relative to health is unknown.

Scientists with USDA's Agricultural Research Service (ARS) in Beltsville, Md., studied the differences between phytochemicals in green tea dietary supplements and green tea leaves used for brewing beverages. ARS is USDA's principal intramural scientific research agency.

Chemist Pei Chen, with the ARS Beltsville Human Nutrition Research Center, headed the study. Chen and colleagues Jianghao Sun and Long-Ze Lin analyzed extractions of 20 commercially available green tea dietary supplement products and eight dry green tea leaf samples. They compared the chemical constituents of the samples using an analytical technique called "HPLC/MS." This technique can separate one chemical constituent from another in a complex matrix. The technique also has the ability to identify and quantify chemical constituents accurately.

The study demonstrated that phytonutrients called flavonol glycosides were degraded and that another phytonutrient called catechin had oxidized during manufacturing and storage for many of the green tea supplement samples studied. They also found some additives in the supplements that were not listed on the labels.

The researchers concluded that although there are fine green tea dietary supplement products, there is no way for the consumer to know the qualities of those products from reading the labels. In addition, the consumer may ingest other botanical extracts unintentionally, and the quality of those green tea products varies significantly. The 2011 study was published in the Journal of AOAC International.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

ARS Food and Nutrition Research Briefs Issued By Kim Kaplan
April 25, 2012

Almonds can be treated with infrared heat and then hot-air roasting so they remain safe from Salmonella. Information on this process, called "SIRHA" (sequential infrared and hot air), is among the new nutrition and health findings noted in the newest issue of the Agricultural Research Service (ARS) Food and Nutrition Research Briefs and its Spanish-language edition (Informe de investigaciones de alimentos y nutrición).

View the English edition here.

The popular online newsletter reports discoveries from researchers at ARS laboratories nationwide.

Other findings in the new issue:

• ARS researchers are providing data on dietary supplement intakes from information in the "What We Eat in America" survey.
  
  
• Even the smallest quantity of Salmonella may, in the future, be easily detected with a technology known as SERS, short for "surface-enhanced Raman scattering."
  
  
• ARS and the Department of Health and Human Services have teamed up to monitor levels of sodium in foods, particularly processed foods and ingredients.

ARS Food and Nutrition Research Briefs is offered with color photos and illustrations on the Web. And by clicking the "subscribe" link on the newsletter's home page, readers can sign up for two e-mail options: They can receive the full text of the newsletter by e-mail, or simply an advisory that a new issue has been posted to the Web.

ARS is the U.S. Department of Agriculture's chief intramural scientific research agency.

Read the magazine story to find out more.

ARS is about to release an updated universal soil loss equation that incorporates more intricate combinations of observation- and process-based science to produce the most accurate soil erosion estimates yet. Click the image for more information about it.

• Modeling erosion of particulate matter
   
• Study shows no-till's benefits for Pacific Northwest wheat growers
   
• A hedge with an edge for erosion control

Soil Erosion Modeling: It's Getting Better All the Time By Ann Perry
April 23 2012

About 50 years ago, scientists at the U.S. Department of Agriculture (USDA) devised the Universal Soil Loss Equation (USLE), a formula farmers could use to estimate losses from soil erosion. Agricultural Research Service (ARS) scientists will soon release a version that integrates models generated by cutting-edge computer technology, an updated soils database, and new findings about erosion processes.

ARS is USDA's chief intramural scientific research agency, and this work supports the USDA priority of promoting international food security.

The original USLE used five factors to estimate the tons of soil lost per acre per year from the impact of raindrops and the flow of runoff water across fields disturbed by plowing and tilling. The formula is now used as the basis for estimating soil erosion wherever land is disturbed by farming or other human activities.

Every conservation plan written by the USDA Natural Resources Conservation Service has been based on soil-erosion calculations derived from USLE or its successors, the Revised Universal Soil Loss Equation (RUSLE) and version 2 (RUSLE2). Now research leader Seth Dabney, who works at the ARS Watershed Physical Processes Research Unit in Oxford, Miss., is putting the finishing touches on an update of RUSLE2, which uses more intricate combinations of observation- and process-based science to produce soil erosion estimates.

New formulas have been added that can generate simulations of pasture plant lifecycles, which in turn can be used to estimate the effects livestock and their different grazing patterns will have on soil erosion. The revised equations can also produce estimates of how much plant residue can be removed from crop and pasture lands for ethanol production without exposing the soil to excessive erosion.

RUSLE2's revised database contains information for the entire United States on climate and soil properties that affect erosion. The database also includes detailed descriptions of management systems that are organized in 75 crop management zones nationally. RUSLE2 can now also be used to predict runoff amounts and to develop a representative runoff event sequence that can be linked with a process-based channel erosion model.

More information about RUSLE2 can be found at http://www.ars.usda.gov/Research/docs.htm?docid=5971.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

ARS scientists have helped create the first-ever, online public catalog of more than 4,000 metabolites that can be found in human blood serum. Click the image for more information about it.

• Potential indicators of type 2 diabetes investigated
   
• Luteolin stars in study of healthful plant compounds
   
• Vitamin A suppresses type 1 diabetes in animal study

Researchers Analyze Metabolites in Blood By Marcia Wood
April 20, 2012

Thousands of small molecules, known as metabolites, circulate throughout the human body in blood. Medical and nutrition researchers are eager to discover more about metabolites—amino acids, sugars, fats and more—because the presence and concentrations of some of these compounds can provide meaningful profiles, or "metabolite signatures," for assessing health or disease risks, or perhaps even for creating personalized recommendations about what to eat for optimal health.

To help expand this knowledge, U.S. Department of Agriculture (USDA) chemist John W. Newman and support scientist Theresa L. Pedersen have participated in an international collaboration to document all of the metabolites in human blood.

The scientists, both with the USDA Agricultural Research Service (ARS) Western Human Nutrition Research Center in Davis, Calif., made their findings available through the project's Serum Metabolome database at www.serummetabolome.ca and via a 2011 peer-reviewed article in the scientific journal PLoS ONE.

Though most of the metabolites documented in the database are not new to science, the database is nonetheless a significant resource. According to Newman, it is the first-ever public catalog of more than 4,000 metabolites in human serum, and represents the most comprehensive coverage of serum metabolites ever offered in one convenient, reliable source.

Newman's group, and scientists at five other centers in the United States and Canada, used various analytical techniques to examine blood samples from healthy adult volunteers and from adults with cardiovascular disease.

His team's analyses focused on lipid metabolites involved in regulating biological processes. These metabolites are formed by the body from fats and oils in foods such as nuts, dairy products, meats and fish.

Newman and his group are interested in determining how the kinds and concentrations of lipids in the body are influenced by eating habits, physical activity patterns, and genetic and environmental factors, and the relation of these lipids to obesity and its adverse effects on health.

For the blood metabolites investigation, Newman's team worked with two technologies: gas chromatography-mass spectroscopy, and ultra-performance liquid chromatography-electrospray ionization-tandem mass spectroscopy.

Read more about this research in the April 2012 issue of Agricultural Research magazine. ARS is the USDA's chief intramural scientific research agency.

New Issue of Healthy Animals Now Online By Sandra Avant
April 18, 2012

The Agricultural Research Service (ARS) today posted a new issue of Healthy Animals. This quarterly online newsletter compiles ARS news and expert resources on the health and well-being of agricultural livestock, poultry and fish.

Each quarter, one article in Healthy Animals focuses on a particular element of ARS animal research. The current issue examines research on leptospirosis, a disease that affects livestock, domestic animals and humans.

Other research highlighted in this issue includes:

• A natural selenium co-product lasts longer in sheep than inorganic supplements.
  
  
• Forage kochia may provide a more nutritious winter option for cattle than traditional rangeland vegetation.
  
  
• Research suggests that soy milk fed to piglets may produce better bone development than cow's milk formula or mother's milk.
  

Professionals interested in animal health issues might want to bookmark the site as a resource for locating animal health experts. An index lists ARS research locations covering 70 animal health topics. These range from specific diseases, such as Lyme disease, to broad subjects such as nutrition or parasites.

The site also provides complete contact information for the 25 ARS research groups that conduct studies aimed at protecting and improving farm animal health.

To receive an e-mail alert about each issue's online posting, contact Sandra Avant, ARS Information Staff, or sign up online.

ARS is the principal intramural scientific research agency for the U.S. Department of Agriculture.

Read the magazine story to find out more.

An ARS scientist has demonstrated a better way to speed up breeding of improved crop varieties through a statistical approach known as Genomic Selection, which makes use of more of the data produced by the growing number of studies focused on DNA sequences in plant genomes. Click the image for more information about it.

• Analyzing the sheep genome for parasite resistance
   
• Researchers uncover genetic link to cattle disease
   
• Wheat genotyping: An invaluable service

A New Approach to Molecular Plant Breeding By Dennis O'Brien
April 16, 2012

A U.S. Department of Agriculture (USDA) scientist has shown researchers and plant breeders a better way to handle the massive amounts of data being generated by plant molecular studies, using an approach that should help speed up development of improved crop varieties.

Jean-Luc Jannink, who is with the Agricultural Research Service (ARS) Plant, Soil and Nutrition Research Unit at the agency's Robert W. Holley Center for Agriculture and Health, in Ithaca, N.Y., has demonstrated that by using a statistical approach known as Genomic Selection (GS), scientists can capture and exploit more of the data produced by the growing number of studies focused on DNA sequences found in plant genomes. GS is currently used in cattle breeding.

ARS is the principal intramural scientific research agency in USDA. This research supports the USDA priorities of improving agricultural sustainability and promoting international food security.

Scientists and plant breeders increasingly use molecular tools to develop improved crop varieties. By identifying genes associated with desirable traits, they don't have to wait to observe crops grown from seeds.

But molecular tools require analyzing massive amounts of data, and important traits like drought tolerance and yield are the result of the combined actions of multiple genes, each with a small effect. These genes are called quantitative trait loci (QTLs), and the conventional Marker-Assisted Selection (MAS) approach to handling molecular data has limited power to detect small-effect QTLs and estimate their effects.

Jannink's recommended GS approach exploits more data by including all of the small-effect QTLs and estimating the effects of all of the known genetic markers in a plant population.

Jannink and his colleagues recently constructed statistical models, using both GS and MAS approaches, and compared how well they could predict values associated with 13 agronomic traits in crosses made from a "training population" assembled for the study. They gauged the model's accuracy by comparing their predictions with field observations of 374 lines of wheat.

The results showed the GS approach was more accurate at predicting trait values. Jannink had similar success in a study using oats. Both studies were published in The Plant Genome. The work is expected to speed up molecular breeding efforts and should prove extremely useful, given the pace of advances in DNA technology.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.
Coating a cotton fiber with clay nanoparticles (left) could someday mean environmentally friendly, flame-retardant cotton apparel and durable goods. Click the image for more information about it.

Closer view of the clay nanoparticle coating of the cotton fiber. Click the image for more information about it.

• Cotton's potential for padding nonwovens
   
• Inside look at cellulose provides insight into cotton crystals
   
• Nanotechnology may be used for food safety

Nanotech Cotton Opens Up New Possibilities for the Fiber—and its Fans By Jan Suszkiw
April 13, 2012

Cotton is going high-tech in New Orleans, La., where a team of U.S. Department of Agriculture (USDA) scientists is continuing a long tradition of innovative research on the prized natural fiber.

Starting in the 1950s, chemist Ruth Benerito and her colleagues at the Agricultural Research Service (ARS) Southern Regional Research Center in New Orleans conducted groundbreaking studies that gave rise to easy-care, permanent-press clothing and other consumer-friendly improvements that helped cotton better compete with synthetic fibers, like polyester. Today, under the leadership of Brian Condon, the ARS cotton researchers in New Orleans are leveraging the latest developments in nanotechnology to bring cotton fully into the 21st century.

ARS is the chief intramural scientific research agency of USDA.

In one ongoing project, the researchers have teamed with Texas A&M University scientists to evaluate a first-of-its-kind, environmentally friendly flame-retardant for cotton apparel and durable goods. Halogenated flame retardants have been among the most widely used chemical treatments, but there's been a push to find alternatives that are more benign and that won't cause treated fabric to stiffen, according to Condon.

Made of water-soluble polymers, 50- to 100-nanometer clay particles and other "green" ingredients, the experimental fabric treatment reacts to open flame by rapidly forming a swollen charred surface layer. This stops the flame from reaching underlying or adjacent fibers in a process known as "intumescence," notes Condon, co-author of a May 2010 ACS Nano paper.

Early trials of the nanocoating using standard flame-resistance tests have been promising. In one case, 95 percent of treated cotton fabric remained intact after exposure to flame versus complete destruction of untreated fabric used for comparison.

In another project, the ARS scientists are generating ultrasonic fields of mechanical energy to improve enzyme-based processing of raw ("greige") cotton to strip away waxes and other fiber components that can hinder subsequent dying procedures and diminish product quality.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

Salmonella or other pathogens in food and beverage samples might be more easily detected if polymer spheres, coated with silver nanoparticles, are used in SERS (surface-enhanced Raman scattering) assays, according ARS studies. Click the image for more information about it.

• Hyperspectral imaging speeds detection of Campylobacter
   
• ARS system to detect poultry contamination passes first commercial test
   
• Nanotechnology may be used for food safety

High-tech Tactic May Expose Stealthy Salmonella By Marcia Wood
April 9, 2012

Even the smallest quantity of Salmonella may, in the future, be easily detected with a technology known as SERS, short for "surface-enhanced Raman scattering." U.S. Department of Agriculture (USDA) scientist Bosoon Park at Athens, Ga., is leading exploratory studies of this analytical technique's potential for quick, easy and reliable detection of Salmonella and other foodborne pathogens.

According to the U.S. Centers for Disease Control and Prevention, Salmonella causes more than one million cases of illness in the United States every year.

If SERS proves successful for cornering Salmonella, the technique might be used at public health laboratories around the nation to rapidly identify this or other pathogens responsible for outbreaks of foodborne illness, according to Park, an agricultural engineer with USDA's Agricultural Research Service (ARS). What's more, tomorrow's foodmakers might use SERS at their in-house quality control labs.

ARS is USDA's chief intramural scientific research agency. Park's research supports the USDA priority of enhancing food safety.

In a SERS analysis, a specimen is placed on a surface, such as a stainless steel plate, that has been "enhanced" or changed from smooth to rough. For some of their research, Park's team enhanced the surface of stainless steel plates by coating them with tiny spheres, made up of a biopolymer encapsulated with nanoparticles of silver.

Rough surfaces, and colloidal metals such as silver, can enhance the scattering of light that occurs when a specimen, placed on this "nanosubstrate," is scanned with the Raman spectrometer's laser beam.

The scattered light that comes back to the spectroscope forms a distinct spectral pattern known as a Raman spectral signature, or Raman scattered signal. Researchers expect to prove the concept that all molecules, such as those that make up Salmonella, have their own unique Raman spectral signature.

The idea of using a substrate of silver nanoparticles for Raman spectroscopy is not new. But in SERS studies to detect foodborne pathogens, the use of a surface—enhanced with biopolymers coated with silver nanoparticles—is apparently novel.

In work with comparatively large concentrations of two different kinds, or serotypes, of Salmonella enterica—Enteritidis and Typhimurium—Park's tests showed, apparently for the first time, that SERS can differentiate these two serotypes. With further research, SERS may prove superior for finding very small quantities of bacteria in a complex, real-world background, such as a food or beverage sample, Park notes.

He collaborated in the research with Arthur Hinton, Jr., Kurt C. Lawrence, Jaya Sundaram, William R. Windham, and Seung Chul Yoon, all with ARS at the agency's Richard B. Russell Research Center in Athens; Yao-Wen Huang and Yiping Zhao of the University of Georgia-Athens; Yongkuk Kwon of South Korea's Animal, Plant, and Fisheries Quarantine and Inspection Agency; and others.

Read more about the research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

Salmonella or other pathogens in food and beverage samples might be more easily detected if polymer spheres, coated with silver nanoparticles, are used in SERS (surface-enhanced Raman scattering) assays, according ARS studies. Click the image for more information about it.

• Hyperspectral imaging speeds detection of Campylobacter
   
• ARS system to detect poultry contamination passes first commercial test
   
• Nanotechnology may be used for food safety

High-tech Tactic May Expose Stealthy Salmonella By Marcia Wood
April 9, 2012

Even the smallest quantity of Salmonella may, in the future, be easily detected with a technology known as SERS, short for "surface-enhanced Raman scattering." U.S. Department of Agriculture (USDA) scientist Bosoon Park at Athens, Ga., is leading exploratory studies of this analytical technique's potential for quick, easy and reliable detection of Salmonella and other foodborne pathogens.

According to the U.S. Centers for Disease Control and Prevention, Salmonella causes more than one million cases of illness in the United States every year.

If SERS proves successful for cornering Salmonella, the technique might be used at public health laboratories around the nation to rapidly identify this or other pathogens responsible for outbreaks of foodborne illness, according to Park, an agricultural engineer with USDA's Agricultural Research Service (ARS). What's more, tomorrow's foodmakers might use SERS at their in-house quality control labs.

ARS is USDA's chief intramural scientific research agency. Park's research supports the USDA priority of enhancing food safety.

In a SERS analysis, a specimen is placed on a surface, such as a stainless steel plate, that has been "enhanced" or changed from smooth to rough. For some of their research, Park's team enhanced the surface of stainless steel plates by coating them with tiny spheres, made up of a biopolymer encapsulated with nanoparticles of silver.

Rough surfaces, and colloidal metals such as silver, can enhance the scattering of light that occurs when a specimen, placed on this "nanosubstrate," is scanned with the Raman spectrometer's laser beam.

The scattered light that comes back to the spectroscope forms a distinct spectral pattern known as a Raman spectral signature, or Raman scattered signal. Researchers expect to prove the concept that all molecules, such as those that make up Salmonella, have their own unique Raman spectral signature.

The idea of using a substrate of silver nanoparticles for Raman spectroscopy is not new. But in SERS studies to detect foodborne pathogens, the use of a surface—enhanced with biopolymers coated with silver nanoparticles—is apparently novel.

In work with comparatively large concentrations of two different kinds, or serotypes, of Salmonella enterica—Enteritidis and Typhimurium—Park's tests showed, apparently for the first time, that SERS can differentiate these two serotypes. With further research, SERS may prove superior for finding very small quantities of bacteria in a complex, real-world background, such as a food or beverage sample, Park notes.

He collaborated in the research with Arthur Hinton, Jr., Kurt C. Lawrence, Jaya Sundaram, William R. Windham, and Seung Chul Yoon, all with ARS at the agency's Richard B. Russell Research Center in Athens; Yao-Wen Huang and Yiping Zhao of the University of Georgia-Athens; Yongkuk Kwon of South Korea's Animal, Plant, and Fisheries Quarantine and Inspection Agency; and others.

Read more about the research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

ARS scientists are using a new technique with gold nanoparticles to design field diagnostic tests for viruses like those that can cause West Nile fever and Rift Valley fever. Click the image for more information about it.

• International partnerships focus on preventing animal diseases
   
• Grasshoppers can transmit virus to livestock
   
• Model successfully predicts Rift Valley fever outbreak

New Technology Sheds Light on Viruses By Sandra Avant
April 6, 2012

Diagnostic tests that rapidly detect disease-causing viruses in animals and humans are being developed by U.S. Department of Agriculture (USDA) scientists using a new technology called "surface-enhanced Raman scattering," or SERS.

With SERS, molecules give off their own unique signals or wavelengths that can be detected with a spectroscope. Viral molecules are labeled with a dye that makes them detectable when a laser is shone on them. Moving a metal such as gold or silver close to the labeled molecules greatly enhances the detection signal.

Microbiologist William Wilson at the Agricultural Research Service (ARS) Center for Grain and Animal Health Research in Manhattan, Kan., used this technology to identify viruses that can cause West Nile fever and Rift Valley fever, both of which are spread by infected mosquitoes. ARS is USDA's chief intramural scientific research agency.

Wilson and his collaborators at the University of Wyoming designed a nucleic acid diagnostic assay to bring molecules close to gold nanoparticles in solution. The gold nanoparticles boost the spectroscopic signal from the indicator molecule, making it easier to detect viral nucleic acid from infected cells. They also developed an immunoassay that rapidly detects antibody responses to viruses.

Scientists hope to eventually adapt the assay to field-based bedside or pen-side diagnostic tools. For example, an instrument similar to a dipstick could be used to rapidly determine areas where a disease outbreak is occurring. Veterinarians could take blood samples from animals on farms, put the samples in small vials and read them with a hand-held device to determine if a virus is present.

Another advantage of the assay is that it can be used to test for multiple pathogens, whereas current pen-side tests are generally agent-specific. The sensitivity of the new diagnostic assay is also greater than the current pen-side system and potentially as good as widely used polymerase chain reaction-based tests.

Findings from this research were published in Biosensors and Bioelectronics and Analytical Chemistry.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

ARS scientists have found a way to differentiate between aphids that can spread viruses to crops and virus-free aphids using protein biomarkers, research that could someday help cut pesticide use. Click the image for more information about it.

• Using a pest's chemical signals to control it
   
• ARS scientists, colleagues sequence genome of major agricultural pest
   
• New barley is bad news for Russian wheat aphid

Reducing Insecticide Use by Identifying Disease-Carrying Aphids By Dennis O'Brien
April 2, 2012

In work that could cut back on insecticide use, U.S. Department of Agriculture (USDA) scientists have found a way to distinguish aphids that spread plant viruses from those that do not.

The researchers used protein biomarkers to differentiate between virus-spreading and virus-free aphids. The findings mark the first time that protein biomarkers have been linked to an insect's ability to transmit viruses.

Aphid-transmitted viruses decrease crop yields and reduce the quality and quantity of fresh foods. Spraying insecticides can control aphids and reduce the incidence of some viruses, but not all aphids transmit viruses, and spraying is expensive and can harm the environment, people and animals.

Agricultural Research Service (ARS) scientists Michelle Cilia and Stewart Gray have found they can identify disease-carrying aphids by examining the types of proteins in their cells. Cilia and Gray work in the Biological Integrated Pest Management Unit at the ARS Robert W. Holley Center for Agriculture and Health in Ithaca, N.Y.

ARS is USDA's chief intramural scientific research agency, and this research supports the USDA priorities of improving agricultural sustainability and promoting international food security.

The researchers knew from previous work that for aphids to pick up and transmit viruses, the virus must be able to interact with specific aphid proteins that direct movement of the virus through the insect and back into a plant during feeding. By studying greenbug aphids in the laboratory, they discovered that the lab-raised insects' ability to transmit yellow dwarf viruses was linked to the presence or absence of nine biomarker proteins found in the insect cells.

They then analyzed greenbug aphids collected from cereal crops and non-cultivated fields and found the aphids consistently transmitted yellow dwarf virus only when they carried most, if not all, of the nine proteins. Field samples were collected by ARS colleagues John Burd and Melissa Burrows at the agency's Wheat, Peanut and Other Field Crops Research Unit in Stillwater, Okla. The aphid does not need all nine proteins to spread the virus, but there are some that are essential.

The discovery in the lab was published in the Journal of Virology, and the field population study was reported in Proteomics. The findings are expected to lead to development of a test to identify potential disease vectors. Cilia and Gray also are collaborating on an expanded effort to test whether biomarker-predictor proteins can be found in other insects.

Read more about this research in the April 2012 issue of Agricultural Research magazine.

Read the magazine story to find out more.

ARS chemist Craig Byrdwell has developed a combination of testing methods that more precisely analyze food samples for vitamin D content. Photo, ARS

• ARS nutrient data available via phone apps and interactive websites
   
• Snacking associated with increased calories, decreased nutrients
   
• Monitoring the population's food and supplement intakes

Better Analysis Methods for Vitamin D By Rosalie Marion Bliss
March 26, 2012

U.S. Department of Agriculture (USDA) researchers with the Beltsville Human Nutrition Research Center in Beltsville, Md., design, develop and improve analytical methods for measuring nutritional components in the food supply. The Beltsville center is part of the Agricultural Research Service (ARS), USDA's principal intramural scientific research agency.

As featured in a three-part series in the March 2012 issue of Agricultural Research magazine, the Beltsville center's Food Composition and Methods Development Laboratory is using new spectrometry methods to discover compounds in foods that have never before been documented.

Accurate data on the amount of vitamins and minerals in the U.S. food supply is critical to accurately assessing the intakes of these nutrients in the U.S. population. At the Beltsville center, chemist Craig Byrdwell has pioneered new, highly precise methods for analyzing vitamin D in foods and dietary supplements.

Byrdwell found that there are many ways in which multiple instruments that measure molecules can be used in parallel to provide much more information about food samples than single instruments used alone. These molecular mass-measuring instruments are called "mass spectrometers." One of Byrdwell's techniques is "triple-parallel mass spectrometry," in which three mass spectrometers, operating in different modes, are used in parallel.

Byrdwell's experiments also have shown that two systems for separating molecules (liquid chromatographs) can be used in combination to analyze complex food samples for vitamin D and its metabolites. Byrdwell authored a book chapter describing his vitamin D analysis methods, which appears in "Extreme Chromatography," published by AOCS Press in Champaign, Ill. Byrdwell is also a coeditor of the book, which was published in May 2011.

Read more about the ARS national program for human nutrition monitoring in Agricultural Research magazine's March 2012 issue.

Helen Taft, a new flowering cherry tree, is being released by ARS to celebrate the 100th anniversary of the Japanese gift of cherry blossoms to the country.

• Wanted: trees for urban landscapes
   
• 100th anniversary of Washington's cherry blossoms celebrated
   
• Historic cherry trees from Japan given new life

Listen to podcast New Cherry Tree Highlights 100th Anniversary of Japanese Gift By Kim Kaplan
March 22, 2012

WASHINGTON, March 22, 2012--The U.S. Department of Agriculture (USDA) has released a new cherry tree variety named for former First Lady Helen Taft to commemorate the 100th anniversary of the Japanese gift of cherry trees that now are a celebrated landmark of the nation's capital.

Helen Herron Taft and Viscountess Iwa Chinda, wife of the Japanese ambassador, planted the first two of the cherry trees at the Tidal Basin in a ceremony on March 27, 1912.

The "Helen Taft" variety is part of a series of flowering cherry tree varieties being developed by the U.S. National Arboretum in Washington and named in honor of first ladies. The new variety was created by crossing a Yoshino cherry (Prunus × yedoensis) with a Taiwan cherry tree (Prunus campanulata). The Yoshino parent, currently growing at the arboretum, is a clone of a tree originally planted by Chinda.

The arboretum is part of the Agricultural Research Service (ARS), USDA's principal intramural scientific research agency.

Growing to as much as 35 feet tall and 35 feet wide over 30 years, "Helen Taft" has large, pale pink single flowers that turn darker in the center as the flowers mature. While most Yoshino flowering trees' blossoms are white or fade to white, the "Helen Taft" flowers retain their pink color.

"Helen Taft is an invaluable addition to the cadre of ornamental cherry trees," said U.S. National Arboretum Director Colien Hefferan. "Unfortunately, cherry trees have a narrow genetic base, especially in this country. That can make them vulnerable to attack by a single insect, disease or environmental stress."

Ornamental cherry trees have a beauty and range of sizes and habits that serve urban gardeners well. Superior urban trees help provide energy savings, cleaner air, better storm water management, and higher property values for home owners. Landscape plants, including ornamental trees, are a $14.3 billion-a-year industry in the United States.

"That's what makes the arboretum's research—expanding the genetic base by creating hybrids with species not often grown here—so important," said geneticist Margaret Pooler, who runs the cherry tree breeding program at the U.S. National Arboretum. "Stronger, well-adapted cherries also require less fertilizer and pesticides, making them even more functional in the landscape. The arboretum fulfills an important role with its long-term breeding program to improve ornamental cherry trees."

With 76 different varieties, the U.S. National Arboretum is home to the Washington area's most diverse array of ornamental cherry trees.

The U.S. National Arboretum has also helped preserve the genetic lineage of the surviving Yoshino cherry trees from the original 1912 gift by propagating 500 trees from them. The new trees were presented to the National Park Service in 1999.

"Helen Taft" is the second variety in the First Lady series. The initial, a 25-foot-tall, upright tree with dark pink, single, semi-pendulous flowers, was released in 2003 and is named "First Lady."

Historical materials documenting Japan's gift of cherry trees to the city of Washington, D.C., are available in the Special Collections of the National Agricultural Library and online at http://riley.nal.usda.gov/cherrytrees.html.