Schneider M.J.,Eastern Regional Research Center |
Mastovska K.,Eastern Regional Research Center |
Solomon M.B.,Beltsville Area Research Center
Journal of Agricultural and Food Chemistry | Year: 2010
The U.S. Food and Drug Administration sets tolerances for veterinary drug residues in muscle but does not specify which type of muscle should be analyzed. To determine if antibiotic residue levels are dependent upon muscle type, seven culled dairy cows were dosed with penicillin G (Pen G) from 1 to 3 days and then sacrificed on day 1, 2, or 5 of withdrawal. A variety (9-15) of muscle samples were collected, along with liver and kidney samples. In addition, corresponding muscle juice samples were prepared. All samples were extracted and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine Pen G levels. Results showed that Pen G residue levels can vary between and within different muscles, although no reproducible pattern was identified between cows or withdrawal times. Muscle juice appeared to be a promising substitute for muscle as a matrix for screening purposes. Because of the potential for variation within muscles, all samples taken need to be large enough to be representative. © This article not subject to U.S. Copyright. Published 2010 by the American Chemical Society.
News Article | December 5, 2016
Raw blueberries, bursting with vitamins and antioxidants, can also harbor the gut-ravaging human norovirus—a leading cause of foodborne illness from fresh produce. Now, scientists think they have found a way to sterilize blueberries without damaging the delicate fruit’s taste or texture: bathing them in purple plumes of plasma—a gas of ions made from just air and electricity. The work is “very promising,” says Peter Bruggeman, a mechanical engineer at the University of Minnesota in Minneapolis who was not involved in the study. Plasma has an advantage over other sterilizing technologies like ultraviolet radiation, he says, because the ionized gas can reach every nook in which norovirus might hide on the surface of the berries. To keep produce germ-free, companies run water-quality tests and try to make sure their equipment is clean. In some cases, workers use chemical washes on fruit, which can leave behind toxic residues and don’t remove some harmful pathogens like norovirus. Just a few infected berries can trigger an outbreak. So researchers turned to plasma. Plasma is the fourth state of matter, created by breaking apart the bonds of gas molecules and making a plume of charged particles—electrons and ions. The plasma created is short-lived and doesn’t create any wastes—the electrons and ions simply recombine. Plasma is all around us: In fluorescent lamps, plasma TVs, lightning bolts; even the sun is made of plasma. But industry also employs it to clean electronic chips and fuse plastics together. In the new study, researchers purchased grocery store blueberries and infected them with two types of norovirus surrogates—noninfectious viruses that behave like the pathogen. (Norovirus is nearly impossible to cultivate in the lab, and it’s safer to use the surrogates.) Then the scientists placed jars of the blueberries under a cylinder that shot out a violet-tinged stream of oxygen and nitrogen plasma—essentially ionized air. The plasma was effective: More than 99.9% of both viruses died within 2 minutes, the team will report in an upcoming issue of . “For viruses that’s really solid performance,” says study author Brendan Niemira, a microbiologist at the U.S. Department of Agriculture’s Eastern Regional Research Center in Wyndmoor, Pennsylvania. Previous research by the team showed the plasma has little effect on the berries’ color, texture, or flavor. Creating plasma makes it hot, so the researchers had to ensure they didn’t end up cooking the blueberries. Nozzles next to some of the jars blew in extra neutral air, cooling the plasma. Plasma in the cooled jars sterilized the fruit just as effectively, the tests showed. “The viruses are still dying, and they’re dying at the same rate they were without this extra air,” Niemira says. This “purple blow torch” is “very reactive and very effective against a wide range of organisms,” says Niemira, referring to the success of previous studies where plasma killed all sorts of bacteria and fungi on produce. Earlier food sterilizing studies have used plasma made from expensive argon and helium gases. It takes more energy to ionize air, but air’s ubiquity makes the approach cheaper overall, Niemira says. The researchers say the purple blow torches require just one-fifth the power needed to run a hair dryer. Niemira says his team is already working to scale up the approach: “We’re making it bigger, we’re making it faster, we’re making it more efficient.” But, scaling up the plasma may pose challenges, cautions Bala Balasubramaniam, a food safety engineer at The Ohio State University in Columbus. For example, uniformly treating hundreds of pounds of berries with plasma could be difficult because the plasma would have to move through many layers of fruit, making it harder to reach every surface where the virus might lurk, he says. For now, scientists don’t quite know how the plasma kills these germs—whether it is the oxygen or nitrogen ions, or other products like ozone or nitrogen oxides that are responsible. “It’s not straightforward,” Bruggeman says. Understanding the mechanism and testing it on the real virus, not just surrogates, he says, would be “the ultimate proof.” By probing the details of plasma kill, scientists hope to move the product to food-processing factories. Niemira guesses it could happen in the next 3 to 5 years. This next step will require working with industrial partners to develop large-scale equipment that will move the process from small jars to massive conveyer belts of berries.
News Article | March 10, 2016
The shrub willow plantation is part of a broader five-year program called NEWBio, which is aimed at investigating and promoting sustainable production of woody biomass and warmseason grasses for energy in the Northeast. Planted in 2012 on land formerly owned by the State Correctional Institution at Rockview, the biomass crop will regrow and will be harvested every three years from now on. NEWBio, a regional consortium of institutions lead by Penn State and funded by the U.S. Department of Agriculture's National Institute of Food and Agriculture, is one of seven regional projects across the United States. Other consortium partners are Cornell University, SUNY College of Environmental Science and Forestry, West Virginia University, Delaware State University, Ohio State University, Rutgers University, USDA's Eastern Regional Research Center, and the U.S. Department of Energy's Oak Ridge National Laboratory and Idaho National Laboratory. Researchers involved in the project include plant scientists, agricultural and biological engineers, agricultural safety and health specialists, agronomists, agricultural and forest economists, rural sociologists, supply-chain and business-development experts, and extension educators. "The shrub willow stand at Rockview can continue producing biomass for more than 20 years, and we hope to use it both as a source of renewable energy and as a platform for sustainability research," said Armen Kemanian, associate professor of production systems and modeling in the Department of Plant Science, one of the lead researchers in the project. "This is an excellent site to investigate impacts on soil and water quality, biodiversity, avoided carbon dioxide emissions, and the potential for growing a regional bio-based economy," he said. "Students from our college visit the site and have a firsthand and close-up view of this new crop for the region." Why shrub willow? Because the woody perennial likes to be cut, explained Kemanian. He noted that visitors to Grand Teton National Park in Wyoming may remember the "willow flats," grazed to a uniform height by moose and elk. "At the Rockview site we don't have moose, but we do take advantage of shrub willow's vigorous regrowth to harvest for multiple cycles," he said. "As perennial plants, they establish a root system that stabilizes the soil and stores substantial amounts of carbon that otherwise would be lost to the atmosphere." Perennial biomass crops shrub willow, switchgrass and miscanthus—all of which are being investigated at other experimental sites around the Northeast—also store and recycle nutrients, so they do not require much fertilizer and can improve water quality in streams, rivers and estuaries, such as the Chesapeake Bay. Increasing perennial vegetation is a critical component of Pennsylvania's water quality strategy, and these biomass crops allow vulnerable parts of the landscape to remain economically productive while protecting water quality. Shrub willow can produce the same amount of biomass as a corn crop with only a third of the nitrogen fertilizer, Kemanian pointed out. When the plants grow, they take carbon dioxide from the atmosphere. After harvest, when the biomass is combusted either as wood chips or as a liquid biofuel, the carbon dioxide returns to the atmosphere to complete the cycle. Felipe Montes, a research associate in the Department of Plant Science, established an array of sensors to measure carbon dioxide and water vapor fluxes, which are giving a vivid picture of the growth potential in the region. Shrub willow is one the first plants to leaf out in early spring and dies back late in the fall, and this long growing season makes it extremely efficient in converting sunlight and nutrients to a bioenergy feedstock. "We estimate that we can harvest 20 to 30 units of energy per unit of fossil energy invested in producing the crop, leading to fuel with a very low carbon footprint," Montes said. "The fact that this biomass can be converted to liquid fuel is one of the main advantages of shrub willow and other biomass crops. Low carbon liquid fuels are especially important for long distance transportation, shipping and aviation, where electric vehicles are not practical." Biomass energy could provide the social, economic and ecological drivers for a sustainable rural renaissance in the Northeast, according to NEWBio project leader Tom Richard, professor of agricultural and biological engineering and director of the Penn State Institutes of Energy and the Environment. He believes perennial energy crops are particularly well suited for the region, where forests and pasture long have dominated the landscape. Rocky and sloped soils are more compatible with perennial crops, while perennial root systems better tolerate wet springs and occasional summer drought, Richard said. Northeast biomass production has high water-use efficiency (biomass produced per unit of water transpired by plants) owing to the region's moderate temperatures and relatively high humidity. These perennial crops also increase organic matter in the soil, and coupled with efficient refining and manufacturing processes can produce carbon-negative energy and materials. "Concerns about energy, environmental and human health, rural economic development, and the need to diversify agricultural products and markets have made the development of sustainably produced biomass feedstocks for biofuels, bioproducts and bioenergy a critical national priority," said Richard. "Perennial bioenergy systems, such as the shrub willow demonstrated at Penn State, appear to hold an important key to future economic development for our region. But to unlock that future, we need to learn how to economically handle the harvesting, transportation and storage of massive volumes, which constitutes 40 to 60 percent of the cost of biomass. This project is providing the knowledge and experience needed for a regional bioeconomy to achieve commercial success." Explore further: Bioenergy crops could store more carbon in soil
Zhou X.,Cornell University |
Cooke P.,Eastern Regional Research Center |
Li L.,Cornell University
Journal of Experimental Botany | Year: 2010
Germination and early seedling development are coordinately regulated by glucose and phytohormones such as ABA, GA, and ethylene. However, the molecules that affect plant responses to glucose and phytohormones remain to be fully elucidated. Eukaryotic release factor 1 (eRF1) is responsible for the recognition of the stop codons in mRNAs during protein synthesis. Accumulating evidence indicates that eRF1 functions in other processes in addition to translation termination. The physiological role of eRF1-2, a member of the eRF1 family, in Arabidopsis was examined here. The eRF1-2 gene was found to be specifically induced by glucose. Arabidopsis plants overexpressing eRF1-2 were hypersensitive to glucose during germination and early seedling development. Such hypersensitivity to glucose was accompanied by a dramatic reduction of the expression of glucose-regulated genes, chlorophyll a/b binding protein and plastocyanin. The hypersensitive response was not due to the enhanced accumulation of ABA. In addition, the eRF1-2 overexpressing plants showed increased sensitivity to paclobutrazol, an inhibitor of GA biosynthesis, and exogenous GA restored their normal growth. By contrast, the loss-of-function erf1-2 mutant exhibited resistance to paclobutrazol, suggesting that eRF1-2 may exert a negative effect on the GA signalling pathway. Collectively, these data provide evidence in support of a novel role of eRF1-2 in affecting glucose and phytohormone responses in modulating plant growth and development.
Farris S.,University of Milan |
Schaich K.M.,Rutgers University |
Liu L.,Eastern Regional Research Center |
Cooke P.H.,Eastern Regional Research Center |
And 2 more authors.
Food Hydrocolloids | Year: 2011
Preparation and properties of composite films from gelatin and low-methoxyl pectin from simultaneous reversible and permanent polyion-complex hydrogels are presented. Ionic interactions between positively charged gelatin and negatively charged pectin produce reversible physical hydrogels with homogeneous molecular arrangement that improve both mechanical and water resistance but do not alter thermal stability relative to single polymer gels. Subsequent addition of 0.3 weight percent (wt.%) glutaraldehyde crosslinks gelatin heterogeneously, due to the presence of domains with non-uniform crosslinking, as revealed by the structural analysis. Resulting interspersed permanent chemical hydrogel showed a decreased swelling attitude by nearly 10 fold relative to films from gelatin alone and further improved mechanical performance (tensile strength and elongation at break). Results demonstrate that simultaneously exploiting the specific reactivity provided by the functional groups of both biopolymers can be used to create unique new structures with improved properties and offer potential for tailoring these to a wide range of targeted applications. © 2010 Elsevier Ltd.
Smith J.L.,Eastern Regional Research Center |
Fratamico P.M.,Eastern Regional Research Center |
Yan X.,Eastern Regional Research Center
Foodborne Pathogens and Disease | Year: 2011
Many gram-negative bacteria utilize N-acyl-L-homoserine lactones (AHLs) to bind to transcriptional regulators leading to activation or repression of target genes. Escherichia coli and Salmonella enterica do not synthesize AHLs but do contain the AHL receptor, SdiA. Studies reveal that SdiA can bind AHLs produced by other bacterial species and thereby allow E. coli and S. enterica to regulate gene transcription. The Salmonella sdiA gene regulates the rck gene, which mediates Salmonella adhesion and invasion of epithelial cells and the resistance of the organism to complement. In E. coli, there is some evidence that SdiA may regulate genes associated with acid resistance, virulence, motility, biofilm formation, and autoinducer-2 transport and processing. However, there is a lack of information concerning the role of SdiA in regulating growth and survival of E. coli and Salmonella in food environments, and therefore studies in this area are needed. © Copyright 2011, Mary Ann Liebert, Inc. 2011.
Renye Jr. J.A.,Eastern Regional Research Center |
Somkuti G.A.,Eastern Regional Research Center
Biotechnology Letters | Year: 2013
Streptococcus thermophilus B59671 produces a bacteriocin with anti-pediococcal activity, but genes required for its production are not characterized. Genome sequencing of S. thermophilus has identified a genetic locus encoding a quorum sensing (QS) system that regulates production of class II bacteriocins. However, in strains possessing this gene cluster, production of bacteriocin like peptides (Blp) was only observed when excess pheromone was provided. PCR analysis revealed this strain possessed blpC, which encodes the 30-mer QS pheromone. To investigate if BlpC regulates bacteriocin production in S. thermophilus B59671, an integrative vector was used to replace blpC with a gene encoding for kanamycin resistance and the resulting mutant did not inhibit the growth of Pediococcus acidilactici. Constitutive expression of blpC from a shuttle vector restored the bacteriocin production, confirming the blp gene cluster is essential for bacteriocin activity in S. thermophilus B59671. © 2012 Springer Science+Business Media Dordrecht (outside the USA).
Renye Jr. J.A.,Eastern Regional Research Center |
Somkuti G.A.,Eastern Regional Research Center
Biotechnology Letters | Year: 2012
The integrative vector, pINTRS, was used to transfer glutamate decarboxylase (GAD) activity to Streptococcus thermophilus ST128 thereby allowing for the production of γ-aminobutyric acid (GABA). In pINTRS, the gene encoding glutamate decarboxylase, gadB, was flanked by DNA fragments homologous to a S. thermophilus pseudogene to allow for integration at a non-essential locus on the chromosome. Screening techniques confirmed the insertion of gadB with either its endogenous promoter or the S. thermophilus P2201 promoter, resulting in the generation of recombinant strains, ST128/gadB or ST128/P2201-gadB. Following the integration event unwanted plasmid DNA, specifically the erythromycin resistance gene, was eliminated from the recombinant strains. Based on the production of GABA, activities of GAD for ST128/gadB and ST128/P2201-gadB were 30. 6 ± 6 and 27. 9 ± 7. 2 μM/mg dry cell wt, respectively. © 2011 Springer Science+Business Media B.V. (outside the USA).
Renye Jr. J.A.,Eastern Regional Research Center |
Somkuti G.A.,Eastern Regional Research Center
Journal of Applied Microbiology | Year: 2010
Aims: To test whether a single vector, nisin-controlled expression (NICE) system could be used to regulate expression of the pediocin operon in Streptococcus thermophilus, Lactococcus lactis subsp. lactis and Lactobacillus casei. Methods and Results: The intact pediocin operon was cloned immediately into pMSP3535 downstream of the nisA promoter (PnisA). The resulting vector, pRSNPed, was electrotransformed into Strep. thermophilus ST128, L. lactis subsp. lactis ML3 and Lact. casei C2. Presence of the intact vector was confirmed by PCR, resulting in the amplification of a 0·8-kb DNA fragment, and inhibition zones were observed for all lactic acid bacteria (LAB) transformants following induction with 50 ng ml-1 nisin, when Listeria monocytogenes Scott A was used as the target bacterium. Using L. monocytogenes NR30 as target, the L. lactis transformants produced hazy zones of inhibition, while the Lact. casei transformants produced clear zones of inhibition. Zones of inhibition were not observed when the Strep. thermophilus transformants were tested against NR30. Conclusions: The LAB hosts were able to produce enough pediocin to inhibit the growth of L. monocytogenes Scott A; the growth of L. monocytogenes NR30 was effectively inhibited only by the Lact. casei transformants. Significance and Impact of the Study: This is the first time that the NICE system has been used to express the intact pediocin operon in these LAB hosts. This system could allow for the in situ production of pediocin in fermented dairy foods supplemented with nisin to prevent listeria contamination. © 2009 The Society for Applied Microbiology. No claim to US Government works.
News Article | January 15, 2016
Now, a team of Agricultural Research Service scientists in Wyndmoor, Pennsylvania, has made key advances in a process that produces a crude liquid called "bio-oil" from agricultural waste. The crude bio-oil is produced by pyrolysis, a process that involves chemical decomposition of plant and other organic matter using very high heat. The modified technique is called "tail-gas reactive pyrolysis" (TGRP). It holds promise for processing and improving the bio-oil, which is ultimately processed into finished biofuel. The Energy Independence and Security Act of 2007 calls for a minimum of 36 billion gallons of advanced biofuels to be produced in the U.S. by the year 2022. This effort will require, in part, the development of a new industry that produces 21 billion gallons of new biofuels based on non-food sources. "Ideally, the biofuels added to gasoline would be identical to fuels produced at petroleum refineries," says chemical engineer Yaseen Elkasabi. The research team, which includes Elkasabi, is headed by chemical engineer Akwasi Boateng with chemist Charles Mullen, and engineers Neil Goldberg and Mark Schaffer, in the Sustainable Biofuels and Coproducts Unit at the ARS Eastern Regional Research Center. Raw material called "biomass" is the basis for producing biofuel, and it includes non-food-grade plant matter procured from agricultural or household waste. "We are using crop and forestry residue, such as wood and switchgrass, and also animal manures to produce bio-oils at an accelerated rate using a new high-output, mobile processing unit," says Mullen. "Rather than shipping large amounts of agricultural waste to a refinery plant at a cost, the mobile reactor allows us to convert the biomass into a more energy-dense bio-oil right on the farm." The goal of using TGRP on the farm is to yield a higher quality bio-oil that is more marketable to biofuel producers than bio-oil made from traditional pyrolysis methods. Construction of the mobile unit was funded by a Biomass Research and Development Initiative grant from USDA's National Institute of Food and Agriculture. At petroleum refineries, distillation is a process used for preparing crude oils into finished fuels. But traditional petroleum refineries are not equipped to distill crude pyrolysis oil because it is highly acidic and has high oxygen content, making it corrosive and thermally unstable. Petroleum is naturally deoxygenated. While crude bio-oil can be deoxygenated by adding a catalyst, that approach is expensive and complex. The ARS team's studies have shown that the new TGRP process provides bio-oils that are similar in composition and properties to those produced by adding the catalyst. "The quality of TGRP deoxygenated liquids is equal to or better than the bio-oil produced by catalytic pyrolysis," says Elkasabi. "TGRP is an important step toward the ultimate goal of producing cleaner bio-oils that can be distilled at existing petroleum refineries."