Agricultural Research Services

Beltsville, MD, United States

Agricultural Research Services

Beltsville, MD, United States
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News Article | February 16, 2017

BINGHAMTON, NY - The ability of small intestine cells to absorb nutrients and act as a barrier to pathogens is "significantly decreased" after chronic exposure to nanoparticles of titanium dioxide, a common food additive found in everything from chewing gum to bread, according to research from Binghamton University, State University of New York. Researchers exposed a small intestinal cell culture model to the physiological equivalent of a meal's worth of titanium oxide nanoparticles--30 nanometers across--over four hours (acute exposure), or three meal's worth over five days (chronic exposure). Acute exposures did not have much effect, but chronic exposure diminished the absorptive projections on the surface of intestinal cells called microvilli. With fewer microvilli, the intestinal barrier was weakened, metabolism slowed and some nutrients--iron, zinc, and fatty acids, specifically--were more difficult to absorb. Enzyme functions were negatively affected, while inflammation signals increased. "Titanium oxide is a common food additive and people have been eating a lot of it for a long time--don't worry, it won't kill you!--but we were interested in some of the subtle effects, and we think people should know about them," said Biomedical Engineering Assistant Professor Gretchen Mahler, one of the authors of the paper. "There has been previous work on how titanium oxide nanoparticles affects microvilli, but we are looking at much lower concentrations," Mahler said. "We also extended previous work to show that these nanoparticles alter intestinal function." Titanium dioxide is generally recognized as safe by the U.S. Food and Drug Administration, and ingestion is nearly unavoidable. The compound is an inert and insoluble material that is commonly used for white pigmentation in paints, paper and plastics. It is also an active ingredient in mineral-based sunscreens for pigmentation to block ultraviolet light. However, it can enter the digestive system through toothpastes, as titanium dioxide is used to create abrasion needed for cleaning. The oxide is also used in some chocolate to give it a smooth texture; in donuts to provide color; and in skimmed milks for a brighter, more opaque appearance which makes the milk more palatable. A 2012 Arizona State University study tested 89 common food products including gum, Twinkies, and mayonnaise and found that they all contained titanium dioxide. About five percent of products in that study contained titanium dioxide as nanoparticles. Dunkin Donuts stopped using powdered sugar with titanium dioxide nanoparticles in 2015 in response to pressure from the advocacy group As You Sow. "To avoid foods rich in titanium oxide nanoparticles you should avoid processed foods, and especially candy. That is where you see a lot of nanoparticles," Mahler said. The paper, "Titanium dioxide nanoparticle ingestion alters nutrient absorption in an in vitro model of the small intestine," was published in NanoImpact. Biomedical Engineering Teaching Assistant and current graduate student Zhongyuan Guo was the lead author of the study, while Nicole J. Martucci '16, current Binghamton graduate student Fabiola Moreno-Olivas, and Elad Tako from the Plant, Soil and Nutrition Laboratory for Agricultural Research Services within the U.S. Department of Agriculture in Ithaca, N.Y. were all co-authors. The research was supported by grants from the Binghamton University Research Foundation, the National Institutes of Health and the CONACYT Fellowship.

News Article | November 13, 2015

Easy to identify with their lime-green coloration and single darker green stripe running down the back, greenbugs are prolific breeders. Like most aphids, males and females are required for mating and reproduction in some geographical areas, while only females are necessary in others. In the South, populations consist of female clones, but above about the 35th parallel, populations comprise both sexes, which mate and produce overwintering eggs. Credit: Richard Grantham. Aptly named for their bright lime color, greenbugs (Schizaphis graminum) have been a major vexation for growers of wheat and sorghum for more than half a century, especially in the Great Plains. As decades of research into the little aphids have accumulated, the time has come for an overview of the little aphid and a summary of control methods, according to Dr. Tom Royer, professor and IPM coordinator at Oklahoma State University. He is the lead author of a new paper on these insects in the open-access Journal of Integrated Pest Management. "This was a good opportunity to summarize the literature, and just keep things up to date on this pest," he explained. One of the interesting aspects of the greenbug is its wide host range and how it manages to do so well in spite of different control measures, Royer said, noting that the aphid will attack not only winter wheat and sorghum, but also other small grains and some turfgrasses. Originally, scientists thought that greenbugs evolved adaptations to newly developed resistant plants or pesticides. The greenbugs that could not overcome the new resistances or pesticides would perish, while the remainder would survive and thrive, passing their superior characteristics on to the next generations, making them harder and harder to control over time. That is not, however, what is actually happening, according to Dr. Royer. "A lot of research now supports the idea that greenbugs are so-called pre-adapted opportunists, which means they already have a lot of different genetic diversity within the species—the variety of characteristics is already there—so based on what we're planting in the field at the time, certain populations simply take the opportunity to succeed," he explained. In other words, greenbug populations rotate, with different populations flourishing when their particular genetic characteristics give them the edge. Another characteristic of this formidable pest is the damage it inflicts on plants while it feeds. Something in its saliva imparts visible injury to a plant, leaving behind noticeably yellowed leaves. "We've always thought that it probably has some kind of toxic interaction with the plant," Royer said. So far, however, researchers still aren't sure exactly what is going on, so that work is continuing. Control of greenbugs remains a challenge, but growers can take steps to keep the insects in check. One method is to plant wheat a little later in the year to avoid early greenbug colonization, but the best approach is to monitor the wheat fields to determine when pesticides make sense, according to Royer. To do that, he advocates the use of Oklahoma State's Glance n' Go system, which he helped to develop over the past decade. The Glance n' Go system typically requires no more than 15 minutes of surveying plants for greenbugs that are either alive or "mummified." Mummified greenbugs signify the presence of their natural enemy, a parasitoid wasp known as Lysiphlebus testaceipes. Growers upload information on their location, time of year, current price of wheat, and control costs into the Glance n' Go system's website, which analyzes the data and calculates a treatment threshold. They can then print a scouting form and take it into the field to determine which areas need to be sprayed. "That means producers treat only those fields that need it," Royer said. While scanning the literature for the JIPM article, Royer was as impressed with the people behind the research as he was with the biology and the tenacity of the greenbug itself. "I saw the work of all of these people that I very much admired, including entomologists like George Teetes, who was president of the Entomological Society of America; Don Peters and Kris Giles here at OSU; some of my colleagues, including Bonnie Pendleton, who was a student of Dr. Teetes; Norm Elliott and other members of the USDA's Agricultural Research Services lab in Oklahoma; and entomologists at Kansas State, Texas A&M, and OSU. The researchers who did the work are people who I'd almost call legends in entomology, so it was really humbling for me to write the article." Explore further: New tool for tracking a voracious pest More information: T. A. Royer et al. Greenbug (Hemiptera: Aphididae) Biology, Ecology, and Management in Wheat and Sorghum, Journal of Integrated Pest Management (2015). DOI: 10.1093/jipm/pmv018

News Article | March 8, 2016

Spinach plants are shown four weeks after treatments in which they were deprived of nitrogen, phosphorous, or potassium. The study recommended ways to improve the nutritional value of spinach. Credit: Chenping Xu. Salinity and nutrient-depleted soil are two major constraints in crop production, especially for vegetable crops. In the January 2016 issue of the Journal of the American Society for Horticultural Science, researchers Chenping Xu and Beiquan Mou from the U.S. Department of Agriculture, Agricultural Research Services, report on a study in which they assessed the effects of salinity and single nutrient (nitrogen, phosphorous, or potassium) deficiency on spinach growth, physiology, and nutritional value. Their results suggest that producers could employ cultural practices that impose either low fertilizer levels or slight salt stress to improve spinach nutritional values and experience only "moderately or slightly reduced" yield. Spinach plants (cultivar 'Crocodile') in the study were watered daily with Hoagland nutrition solution, deprived of nitrogen, phosphorous, or potassium for nutrient deficiency, either with or without 20/10 mM sodium chloride/calcium chloride for salinity treatment. Results showed that salinity "greatly inhibited" plant growth, as indicated by reduced shoot fresh weight and dry weight. The researchers also analyzed the effects of the treatments on nutritional values of the spinach. Among other findings, they determined that salt stress increased carotenoid content under complete nutrient treatment. Nitrogen deficiency greatly reduced carotenoid content either with (by 45%) or without (by 50%) salt stress, while phosphorous and potassium deficiencies increased carotenoid content without salt stress. Anthocyanin content was greatly enhanced under nitrogen deficiency (by 145% and 88% under no-salt controls and under salt stress, respectively), but neither salt stress nor phosphorous or potassium deficiency influenced anthocyanin content. Spinach plants' total antioxidant capacity increased under no-salt treatments with nitrogen or potassium deficiency. "These results suggest that the nutritional value of spinach could be improved with only moderately or slightly reduced yield through cultural practices that impose either low fertilizer levels or slight salt stress," the authors concluded. More information: The complete study and abstract are available on the ASHS J. Amer. Soc. Hort. Sci. electronic journal web site:

Otkin J.A.,University of Wisconsin - Madison | Anderson M.C.,Agricultural Research Services | Hain C.,University of Maryland College Park | Mladenova I.E.,Agricultural Research Services | And 2 more authors.
Journal of Hydrometeorology | Year: 2013

Reliable indicators of rapid drought onset can help to improve the effectiveness of drought early warning systems. In this study, the evaporative stress index (ESI), which uses remotely sensed thermal infrared imagery to estimate evapotranspiration (ET), is compared to drought classifications in the U.S. Drought Monitor (USDM) and standard precipitation-based drought indicators for several cases of rapid drought development that have occurred across the United States in recent years. Analysis of meteorological time series from the North American Regional Reanalysis indicates that these events are typically characterized by warm air temperature and low cloud cover anomalies, often with high winds and dewpoint depressions that serve to hasten evaporative depletion of soil moisture reserves. Standardized change anomalies depicting the rate at which various multiweek ESI composites changed over different time intervals are computed to more easily identify areas experiencing rapid changes in ET. Overall, the results demonstrate that ESI change anomalies can provide early warning of incipient drought impacts on agricultural systems, as indicated in crop condition reports collected by the National Agricultural Statistics Service. In each case examined, large negative change anomalies indicative of rapidly drying conditions were either coincident with the introduction of drought in theUSDM or lead the USDM drought depiction by several weeks, depending on which ESI composite and time-differencing interval was used. Incorporation of the ESI as a data layer used in the construction of the USDM may improve timely depictions of moisture conditions and vegetation stress associated with flash drought events. © 2013 American Meteorological Society.

Boddicker N.J.,Iowa State University | Garrick D.J.,Iowa State University | Garrick D.J.,Massey University | Rowland R.R.R.,Kansas State University | And 3 more authors.
Animal Genetics | Year: 2014

Infectious diseases are costly to the swine industry; porcine reproductive and respiratory syndrome (PRRS) is the most devastating. In earlier work, a quantitative trait locus associated with resistance/susceptibility to PRRS virus was identified on Sus scrofa chromosome 4 using approximately 560 experimentally infected animals from a commercial cross. The favorable genotype was associated with decreased virus load and increased weight gain (WG). The objective here was to validate and further characterize the association of the chromosome 4 region with PRRS resistance using data from two unrelated commercial crossbred populations. The validation populations consisted of two trials each of approximately 200 pigs sourced from different breeding companies that were infected with PRRS virus and followed for 42 days post-infection. Across all five trials, heritability estimates were 0.39 and 0.34 for viral load (VL; area under the curve of log-transformed viremia from 0 to 21 days post-infection) and WG to 42 days post-infection respectively. Effect estimates of SNP WUR10000125 in the chromosome 4 region were in the same directions and of similar magnitudes in the two new trials as had been observed in the first three trials. Across all five trials, the 1-Mb region on chromosome 4 explained 15 percent of genetic variance for VL and 11 percent for WG. The effect of the favorable minor allele at SNP WUR10000125 was dominant. Ordered genotypes for SNP WUR10000125 showed that the effect was present irrespective of whether the favorable allele was paternally or maternally inherited. These results demonstrate that selection for host response to PRRS virus infection could reduce the economic impact of PRRS. © 2013 Stichting International Foundation for Animal Genetics.

Boddicker N.J.,Iowa State University | Bjorkquist A.,Iowa State University | Rowland R.R.,Kansas State University | Lunney J.K.,Agricultural Research Services | And 2 more authors.
Genetics Selection Evolution | Year: 2014

Background: Host genetics has been shown to play a role in porcine reproductive and respiratory syndrome (PRRS), which is the most economically important disease in the swine industry. A region on Sus scrofa chromosome (SSC) 4 has been previously reported to have a strong association with serum viremia and weight gain in pigs experimentally infected with the PRRS virus (PRRSV). The objective here was to identify haplotypes associated with the favorable phenotype, investigate additional genomic regions associated with host response to PRRSV, and to determine the predictive ability of genomic estimated breeding values (GEBV) based on the SSC4 region and based on the rest of the genome. Phenotypic data and 60 K SNP genotypes from eight trials of ∼200 pigs from different commercial crosses were used to address these objectives. Results: Across the eight trials, heritability estimates were 0.44 and 0.29 for viral load (VL, area under the curve of log-transformed serum viremia from 0 to 21 days post infection) and weight gain to 42 days post infection (WG), respectively. Genomic regions associated with VL were identified on chromosomes 4, X, and 1. Genomic regions associated with WG were identified on chromosomes 4, 5, and 7. Apart from the SSC4 region, the regions associated with these two traits each explained less than 3% of the genetic variance. Due to the strong linkage disequilibrium in the SSC4 region, only 19 unique haplotypes were identified across all populations, of which four were associated with the favorable phenotype. Through cross-validation, accuracies of EBV based on the SSC4 region were high (0.55), while the rest of the genome had little predictive ability across populations (0.09). Conclusions: Traits associated with response to PRRSV infection in growing pigs are largely controlled by genomic regions with relatively small effects, with the exception of SSC4. Accuracies of EBV based on the SSC4 region were high compared to the rest of the genome. These results show that selection for the SSC4 region could potentially reduce the effects of PRRS in growing pigs, ultimately reducing the economic impact of this disease. © 2014 Boddicker et al.; licensee BioMed Central Ltd.

Truong A.D.,Chung - Ang University | Hong Y.H.,Chung - Ang University | Lillehoj H.S.,Agricultural Research Services
Veterinary Immunology and Immunopathology | Year: 2015

We investigated the necrotic enteritis (NE)-induced transcripts of immune-related genes in the intestinal mucosa of two highly inbred White Leghorn chicken lines, line 6.3 and line 7.2, which share the same MHC haplotype and show different levels of NE susceptibility using high-throughput RNA sequencing (RNA-Seq) technology. NE was induced by the previously described co-infection model using Eimeria maxima and Clostridium perfringens. The RNA-Seq generated over 38 million sequence reads for Marek's disease (MD)-resistant line 6.3 and over 40 million reads for the MD-susceptible line 7.2. Alignment of these sequences with the Gallus gallus genome database revealed the expression of over 29,900 gene transcripts induced by NE in these two lines, among which 7,841 genes were significantly upregulated and 2,919 genes were downregulated in line 6.3 chickens and 6,043 genes were significantly upregulated and 2,764 genes were downregulated in NE-induced line 7.2 compared with their uninfected controls. Analysis of 560 differentially expressed genes (DEGs) using the gene ontology database revealed annotations for 246 biological processes, 215 molecular functions, and 81 cellular components. Among the 53 cytokines and 96 cytokine receptors, 15 cytokines and 29 cytokine receptors were highly expressed in line 6.3, whereas the expression of 15 cytokines and 15 cytokine receptors was higher in line 7.2 than in line 6.3 (fold change. ≥. 2, p<. 0.01). In a hierarchical cluster analysis of novel mRNAs, the novel mRNA transcriptome showed higher expression in line 6.3 than in line 7.2, which is consistent with the expression profile of immune-related target genes.In qRT-PCR and RNA-Seq analysis, all the genes examined showed similar responses to NE (correlation coefficient R=. 0.85-0.89, p<. 0.01) in both lines 6.3 and 7.2. This study is the first report describing NE-induced DEGs and novel transcriptomes using RNA-seq data from two inbred chicken lines showing different levels of NE susceptibility. These findings provide important insights into our current knowledge of host-pathogen interaction and the nature of host genes that can serve as NE resistance markers for molecular breeding. © 2015 Elsevier B.V.

Dinh H.,Chung - Ang University | Hong Y.H.,Chung - Ang University | Lillehoj H.S.,Agricultural Research Services
Veterinary Immunology and Immunopathology | Year: 2014

MicroRNAs (miRNA) play a critical role in post-transcriptional regulation by influencing the 3'-UTR of target genes. Using two inbred White Leghorn chicken lines, line 6.3 and line 7.2 showing Marek's disease-resistant and -susceptible phenotypes, respectively, we used small RNA high-throughput sequencing (HTS) to investigate whether miRNAs are differently expressed in these two chicken lines after inducing necrotic enteritis (NE). The 12 miRNAs, selected from the most down-regulated or up-regulated miRNAs following NE induction, were confirmed by their expressions in real-time PCR. Among these miRNAs, miR-215, miR-217, miR-194, miR-200a, miR-200b, miR-216a, miR-216b, and miR-429 were highly expressed in intestine derived from line 7.2, whereas, miR-1782 and miR-499 were down-regulated. In spleen, miR-34b and miR-1684 were the most up-regulated miRNAs in line 6.3. Notably, five out of six target genes, CXCR5, BCL2, GJA1, TCF12, and TAB3 were differentially expressed between line 6.3 and line 7.2, and showed suppression in the MD-susceptible chicken line. Their expression levels were conversely correlated with those of miRNA obtained from both HTS and quantitative real-time PCR.These results suggest that some miRNAs are differentially altered in response to NE and they modulate the expression of their target genes in the two inbred lines. Collectively, HTS analysis of intestinal miRNAs from NE-afflicted inbred chickens showing different disease phenotypes led to the identification of host immunity genes regulated by miRNA. Future studies of the function of these miRNAs and their target genes in the host will lead to enhanced understanding of molecular mechanisms controlling host-pathogen interaction in NE. © 2014 Elsevier B.V.

Chung S.-Y.,Agricultural Research Services | Reed S.,Agricultural Research Services
Food Chemistry | Year: 2015

The objective of this study was to determine if d-amino acids (d-aas) bind and inhibit immunoglobulin E (IgE) binding to peanut allergens. d-aas such as d-Asp (aspartic acid), d-Glu (glutamic acid), combined d-[Asp/Glu] and others were each prepared in a cocktail of 9 other d-aas, along with l-amino acids (l-aas) and controls. Each sample was mixed with a pooled plasma from peanut-allergic donors, and tested by ELISA (enzyme-linked immunosorbent assay) and Western blots for IgE binding to peanut allergens. Results showed that d-[Asp/Glu] (4 mg/ml) inhibited IgE binding (75%) while d-Glu, d-Asp and other d-aas had no inhibitory effect. A higher inhibition was seen with d-[Asp/Glu] than with l-[Asp/Glu]. We concluded that IgE was specific for d-[Asp/Glu], not d-Asp or d-Glu, and that d-[Asp/Glu] was more reactive than was l-[Asp/Glu] in IgE inhibition. The finding indicates that d-[Asp/Glu] may have the potential for removing IgE or reducing IgE binding to peanut allergens in vitro.

Chang H.-X.,Urbana University | Miller L.A.,Urbana University | Hartman G.L.,Urbana University | Hartman G.L.,Agricultural Research Services
Phytopathology | Year: 2014

Appressoria of some plant-pathogenic fungi accumulate turgor pressure that produces a mechanical force enabling the direct penetration of hyphae through the epidermis. Melanin functions as an impermeable barrier to osmolytes, which allows appressoria to accumulate high turgor pressure. Deficiency of melanin in appressoria reduces turgor pressure and compromises the infection process. In Phakopsora pachyrhizi, the soybean rust pathogen, the appressoria are hyaline. Our objective was to ensure the absence of a melanin layer specifically between the appressorial cell wall and plasma membrane, as well as to determine the turgor pressure of P. pachyrhizi appressoria. We demonstrated that two melanin biosynthesis inhibitors neither reduced turgor pressure nor compromised the infection process. Transmission electron microscopy also showed the absence of a melanin layer between the appressorial cell wall and plasma membrane. In addition, the turgor pressure of P. pachyrhizi appressoria was 5 to 6 MPa, based on extracellular osmolytes used to simulate different osmotic pressures. This is the first report showing that turgor pressure accumulation of P. pachyrhizi appressoria was independent of melanin.

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