Beltsville Agricultural Research Center

Baltimore Highlands, MD, United States

Beltsville Agricultural Research Center

Baltimore Highlands, MD, United States

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Home > Press > News from Quorum: The Agricultural Research Service of the USDA uses a Quorum Cryo-SEM preparation system for the study of mites, ticks and other soft bodied organisms Abstract: Quorum Technologies, market and technology leaders in electron microscopy coating and cryogenic preparation products, report on the work of the Agricultural Research Service of the US Department of Agriculture where their PP2000 Cryo-SEM preparation system is in use to prepare soft bodied organisms including mites & ticks for study using cryo-SEM Dr Gary Bauchan is the Director of the Electron and Confocal Microscopy Unit at the Agricultural Research Service (ARS), the principal in-house research agency of the United States Department of Agriculture. The Unit is a core facility with the responsibility of providing collaborative assistance to scientists from ARS, Northeast Area and Beltsville Agricultural Research Center (BARC) who have microscopy applications that require high resolution imaging. Dr Bauchan’s team have produced images using electron microscopes of bacteria, fungi, mites, insects, nematodes and parasites along with plant and animal tissues both healthy and diseased. One of his major collaborations is with Dr Ron Ochoa, the world's expert on plant feeding mites. Biological specimens require special treatment due to the high water content of the samples. Many of the specimens are in liquid cultures or are very soft-bodied and by using classical preparative techniques will either destroy the specimen or distort the specimen producing artefacts. A cryo-prep system is an ultra-fast method to ready the specimens for observation in a SEM especially a high resolution field emission SEM. Thus, specimens are frozen in time to allow for observation of feeding behaviour, mating behaviour, host/parasite interactions, etc. It preserves the natural orientation of ultrafine structures such as setae, antenna, legs, skin texture, sensory organs, waxy coatings and eggs. Asked about his experience using a Quorum PP2000 Cryo-SEM preparation system on the Hitachi S-4700 field emission scanning electron microscope, Dr Bauchan said “The Quorum system is easy to use, the set-up for imaging is logical, durable, reliable, and maintains ultra-low temperatures for a long period of time. Holders containing pre-frozen samples are transferred into the cryo-prep chamber where they are etched to remove any surface contamination (condensed water vapour) by raising the temperature of the stage from -130 ºC to -90 °C for 10-15 minutes. Following etching, the temperature inside the chamber was lowered below -130 °C, and the specimens were coated with a 10 nm layer of platinum using a magnetron sputter head equipped with a platinum target. The specimens were transferred to a pre-cooled (-130 °C) cryo-stage in the SEM for observation.” The system has been used in multiple projects by the Unit, many of which have been published with the generation of stunning, colourful images. The use of low temperature SEM has been shown time and again to be the best method for the examination of microscopic biological specimens and their ultrastructure. The work in conjunction with Dr Ochoa has been particularly productive with five papers published this year to date. These have focused on the field of acarology, a branch of zoology dealing with the study of mites and ticks. The PP2000 is one of Quorum's highly automated, easy-to-use, column-mounted, gas-cooled cryo-SEM preparation systems suitable for most makes and models of SEM, FE-SEM and FIB/SEM. To obtain full details of the latest cryo-SEM preparation systems and other products available from Quorum Technologies, please visit Note to editors from USDA-ARS: “Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA.” About Quorum Technologies Limited Quorum Technologies are market and technology leaders in electron microscopy (EM) coating and cryogenic preparation. The company was founded in 2001 after the acquisition of the long-established Polaron brand and its range of EM products from Thermo Instruments. In 2005, Quorum acquired the Emitech company allowing the extension of their product range and further growth of the business. Since the start, Quorum has responding to industry requests and requirements for new instruments and techniques. This first culminated in the introduction of the market-leading Q Series of vacuum coaters and PP3010T cryo preparation system for SEM and FIB/SEM - true ground-up redesigns that have truly set the standard within the specimen preparation field. Further impetus and investment came with the acquisition of Quorum by Judges Scientific plc and a move to purpose-built factory and offices close to the South Downs National Park at Laughton, East Sussex in the South East of England. In 2014 Quorum were proud winners of the Queen's Award for Enterprise for International Trade. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bevacqua C.E.,University of Maryland College Park | Rice C.P.,Beltsville Agricultural Research Center | Torrents A.,University of Maryland College Park | Ramirez M.,District of Columbia Water and Sewer Authority
Science of the Total Environment | Year: 2011

Steroid hormones can act as potent endocrine disruptors when released into the environment. The main sources of these chemicals are thought to be wastewater treatment plant discharges and waste from animal feeding operations. While these compounds have frequently been found in wastewater effluents, few studies have investigated biosolids or manure, which are routinely land applied, as potential sources. This study assessed the potential environmental contribution of steroid hormones from biosolids and chicken litter. Hormone concentrations in samples of limed biosolids collected at a waste treatment plant over a four year period ranged from < 2.5 to 21.7. ng/g dry weight for estrone (E1) and < 2.5 to 470. ng/g dry weight for progesterone. Chicken litter from 12 mid-Atlantic farms had averages of 41.4. ng/g dry weight E1, 63.4. ng/g dry weight progesterone, and 19.2. ng/g dry weight E1-sulfate (E1-S). Other analytes studied were 17β-estradiol (E2), estriol (E3), 17β-ethinylestradiol (EE2), testosterone, E2-3-sulfate (E2-3-S), and E2-17-sulfate (E2-17-3). © 2011 Elsevier B.V.

Shwab E.K.,University of Tennessee at Knoxville | Jiang T.,University of Tennessee at Knoxville | Pena H.F.J.,University of Sao Paulo | Gennari S.M.,University of Sao Paulo | And 2 more authors.
International Journal for Parasitology | Year: 2016

The protozoan parasite Toxoplasma gondii is one of the most successful known eukaryotic pathogens on Earth. Virulence of T. gondii strains varies greatly in mice, and mounting evidence suggests that such variations may be relevant to the manifestation of human toxoplasmosis. Polymorphic rhoptry-secreted kinases and pseudokinases (ROP) have been demonstrated to account for murine virulence among the archetypal clonal parasite lineages that dominate the populations of North America and Europe. However, the distribution of virulence gene alleles in natural populations and the broad influence of these allele combinations on T. gondii virulence have not been examined in depth. In the present study, we performed PCR-RFLP genotyping analysis on a diverse array of globally distributed T. gondii strains at four ROP gene loci including ROP18, ROP5, ROP16 and ROP17 that were previously implicated in influencing T. gondii virulence and pathogenesis. We demonstrated through correlation with published virulence data that the combination of ROP18 and ROP5 allele types is highly predictive of T. gondii virulence across a broad range of global T. gondii isolates. These findings indicate that the importance of ROP18 and ROP5 in determining strain virulence is not limited to the North American/European archetypal lineages most commonly used in molecular studies, but also appears to apply to diverse isolates from South/central America and Asia. Restriction fragment length polymorphism analysis of these loci may thus serve as a valuable tool in determining the potential virulence of uncharacterized T. gondii strains in future studies. © 2015 .

Delwiche S.R.,U.S. Department of Agriculture | Kim M.S.,Beltsville Agricultural Research Center | Dong Y.,University of Minnesota
Sensing and Instrumentation for Food Quality and Safety | Year: 2011

Fusarium head blight is a fungal disease that affects the world's small grains, such as wheat and barley. Attacking the spikelets during development, the fungus causes a reduction of yield and grain of poorer processing quality. Secondary metabolites that often accompany the fungus, such as deoxynivalenol (DON), are health concerns to humans and livestock. Conventional grain inspection procedures for Fusarium damage are heavily reliant on human visual analysis. As an inspection alternative, a near-infrared (NIR) hyperspectral image system (1000-1700 nm) was fabricated and applied to Fusarium-damaged kernel recognition. An existing extended visible (400-1000 nm) system was similarly used. Exhaustive searches were performed on the 144 and 125 wavelength pair images that, respectively, comprised the NIR and visible systems to determine accuracy of classification using a linear discriminant analysis (LDA) classifier. On a limited set of wheat samples the best wavelength pairs, either with visible or NIR wavelengths, were able to discriminate Fusarium-damaged kernels from sound kernels, both based on visual assessment, at an average accuracy of approximately 95%. Accuracy dropped off substantially when the visual contrast between the two kernel conditions became imperceptible. The NIR region was slightly better than the visible region in its broader array of acceptable wavelength pairs. Further, the region of interest (ROI) defined as the whole kernel was slightly better than ROIs limited to either a portion of the endosperm or the germ tip. For the NIR region, the spectral absorption near 1200 nm, attributed to ergosterol (a primary constituent in fungi cell membranes), was shown to be useful in spectral recognition of Fusarium damage. © 2011 Springer Science+Business Media, LLC.

Farnham M.W.,U.S. Department of Agriculture | Lester G.E.,Beltsville Agricultural Research Center | Hassell R.,Clemson University
Journal of Food Composition and Analysis | Year: 2012

Leaf green Brassica crops: collard (Brassica oleracea L.), mustard (Brassica juncea L.) and turnip (Brassica rapa L.) greens are important commercial and culinary vegetables, especially in the southern United States. However, almost no information on essential human-health vitamins [ascorbic acid (vitamin C), folate (vitamin B 9), phylloquinone (vitamin K 1) and the carotenoids lutein and β-carotene (provitamin A)] is available. Leafy green Brassicas (15 collard, 2 mustard and 2 turnip greens) were harvested at peak whole-plant maturity, separated into younger (top-canopy) or older (bottom-canopy) leaves and assayed for the aforementioned vitamins and carotenoids. On a 100g fresh mass basis, percent dry mass (14.7g versus 13.2g), total (132.7mg versus 109.1mg) and free (58.7mg versus 52.8mg) ascorbic acid, folate (183μg versus 112μg) and lutein (9790μg versus 8950μg) concentrations were significantly higher in younger versus older leaves. Phylloquinone (435μg versus 459μg) and β-carotene (11,130μg versus 11,619μg) were equally concentrated in younger and older leaves. On a fresh mass basis, all vitamins were found to be highly concentrated in all nineteen leafy green Brassica genotypes, with particular genotypes within each Brassica species having exceptionally high concentrations. Findings from this study revealed that leafy green Brassica genotypes are nutritionally dense in essential human-health vitamins C, B 9, K, provitamin A (β-carotene) and lutein. Concentration differences in the examined nutritional components among the genotypes (e.g. significant differences in lutein concentrations from 5120 to 15,360μg/100gfm) reveal potential differences that might be exploited in genetic improvement through plant selection and breeding. © 2012.

Crook D.J.,U.S. Department of Agriculture | Khrimian A.,Beltsville Agricultural Research Center | Cosse A.,National United University | Fraser I.,Ford Motor Company | Mastro V.C.,U.S. Department of Agriculture
Journal of Economic Entomology | Year: 2012

Field trapping assays were conducted in 2009 and 2010 throughout western Michigan, to evaluate lures for adult emerald ash borer, A. planipennis Fairmaire (Coleoptera: Buprestidae). Several ash tree volatiles were tested on purple prism traps in 2009, and a dark green prism trap in 2010. In 2009, six bark oil distillate lure treatments were tested against manuka oil lures (used in 2008 by USDA APHIS PPQ emerald ash borer cooperative program). Purple traps baited with 80/20 (manuka/phoebe oil) significantly increased beetle catch compared with traps baited with manuka oil alone. In 2010 we monitored emerald ash borer attraction to dark green traps baited with six lure combinations of 80/20 (manuka/phoebe), manuka oil, and (3Z)-hexenol. Traps baited with manuka oil and (3Z)-hexenol caught significantly more male and total count insects than traps baited with manuka oil alone. Traps baited with manuka oil and (3Z)-hexenol did not catch more beetles when compared with traps baited with (3Z)-hexenol alone. When compared with unbaited green traps our results show that (3Z)-hexenol improved male catch significantly in only one of three field experiments using dark green traps. Dark green traps caught a high number of A. planipennis when unbaited while (3Z)-hexenol was seen to have a minimal (nonsignificant) trap catch effect at several different release rates. We hypothesize that the previously reported kairomonal attractancy of (3Z)-hexenol (for males) on light green traps is not as obvious here because of improved male attractancy to the darker green trap. © 2012 Entomological Society of America.

Kim E.-S.,Beltsville Agricultural Research Center | Kim E.-S.,Iowa State University | Sonstegard T.S.,Beltsville Agricultural Research Center | Rothschild M.F.,Iowa State University
BMC Genomics | Year: 2015

Background: Genome signatures of artificial selection in U.S. Jersey cattle were identified by examining changes in haplotype homozygosity for a resource population of animals born between 1953 and 2007. Genetic merit of this population changed dramatically during this period for a number of traits, especially milk yield. The intense selection underlying these changes was achieved through extensive use of artificial insemination (AI), which also increased consanguinity of the population to a few superior Jersey bulls. As a result, allele frequencies are shifted for many contemporary animals, and in numerous cases to a homozygous state for specific genomic regions. The goal of this study was to identify those selection signatures that occurred after extensive use of AI since the 1960, using analyses of shared haplotype segments or Runs of Homozygosity. When combined with animal birth year information, signatures of selection associated with economically important traits were identified and compared to results from an extended haplotype homozygosity analysis. Results: Overall, our results reveal that more recent selection increased autozygosity across the entire genome, but some specific regions increased more than others. A genome-wide scan identified more than 15 regions with a substantial change in autozygosity. Haplotypes found to be associated with increased milk, fat and protein yield in U.S. Jersey cattle also consistently increased in frequency. Conclusions: The analyses used in this study was able to detect directional selection over the last few decades when individual production records for Jersey animals were available. © Kim et al.; licensee BioMed Central.

Postnikova O.A.,Beltsville Agricultural Research Center | Shao J.,Beltsville Agricultural Research Center | Nemchinov L.G.,Beltsville Agricultural Research Center
Molecular Genetics and Genomics | Year: 2014

Transcription factors (TFs) are proteins that govern organismal development and response to the environment by regulating gene expression. Information on the amount and diversity of TFs within individual plant species is critical for understanding of their biological roles and evolutionary history across the plant kingdom. Currently, only scattered information on separate TFs is available for alfalfa, the most extensively cultivated forage legume in the world. In the meantime, several large transcriptomic resources that can be used to identify and characterize alfalfa TF genes are freely accessible online. In this study, we have performed an in silico analysis of transcriptome data generated in our laboratory and publicly acquirable from other sources to reveal and systematize alfalfa transcription factors. Transcriptome-wide mining enabled prediction of 983 TFs along with their sequence features and putative phylogenies of the largest families. All data were assembled into a simple open-access database named AlfalfaTFDB ( alfalfatfdb.html ). Transcriptomic analysis used in this work represents an effective approach for the identification of TF genes in plants with incomplete genomes, such as alfalfa. Integrated TF repertoires of Medicago sativa will provide an important tool for studying regulation of gene expression in other complex non-model species of agricultural significance. © 2014 Springer-Verlag.

Yang T.,Beltsville Agricultural Research Center | Peng H.,Beltsville Agricultural Research Center | Whitaker B.D.,Beltsville Agricultural Research Center | Jurick W.M.,Beltsville Agricultural Research Center
Physiologia Plantarum | Year: 2013

Calcium has been shown to enhance stress tolerance, maintain firmness and reduce decay in fruits. Previously we reported that seven tomato SlSRs encode calcium/calmodulin-regulated proteins, and that their expressions are developmentally regulated during fruit development and ripening, and are also responsive to ethylene. To study their expressions in response to stresses encountered during postharvest handling, tomato fruit at the mature-green stage was subjected to chilling and wounding injuries, infected with Botrytis cinerea and treated with salicylic acid or methyl jasmonate. Gene expression studies revealed that the seven SlSRs differentially respond to different stress signals. SlSR2 was the only gene upregulated by all the treatments. SlSR4 acted as a late pathogen-induced gene; it was upregulated by salicylic acid and methyl jasmonate, but downregulated by cold treatment. SlSR3L was cold- and wound-responsive and was also induced by salicylic acid. SlSR1 and SlSR1L were repressed by cold, wounding and pathogen infection, but were upregulated by salicylic acid and methyl jasmonate. Overall, results of these expression studies indicate that individual SlSRs have distinct roles in responses to the specific stress signals, and SlSRs may act as a coordinator(s) connecting calcium-mediated signaling with other stress signal transduction pathways during fruit ripening and storage. © 2013 Scandinavian Plant Physiology Society.

Metabolites and stress related transcripts were measured in Arabidopsis thaliana in response to chilling temperatures. Rates of carbon assimilation increased 17% on average in response to cold treatment. Sucrose, glucose and fructose accumulation consumed 42% of the carbon from A but leaf starch only could synthesize ∼10% of observed changes in soluble sugars. Carbohydrates were the only major class of metabolites that accumulated during the first 24. h of cold treatment. Except maltose and raffinose, carbohydrate accumulation was abolished when cold treatments were in darkness. Starch hydrolysis was correlated with maltose accumulation and increased expression of BAM3, which encodes a β-amylase necessary for starch mobilization. Hexose accumulation was delayed 6. h and raffinose accumulation was not observed in a starchless (pgm1) mutant. Changes of expression of five stress-induced transcripts in response to cold were similar in the wild type and in the pgm1 mutant. Three of five stress related transcripts had decreased expression when cold treatments were performed in the dark compared to the light. Therefore, starch hydrolysis may augment hexose and raffinose accumulations during the first 24. h after a cold shock and a partial cold stress response was observed in Arabidopsis during cold treatments in the dark. © 2011.

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