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Food & Nutrition Research Briefs
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Precise details of how six natural compounds in plants—luteolin, quercetin, chrysin, eriodicytol, hesperetin, and naringenin—apparently act as anti-inflammatory agents in the human body are being teased out in studies led by Agricultural Research Service (ARS) scientists. Luteolin is found in celery, thyme, green peppers and chamomile tea. Foods rich in quercetin include capers, apples, and onions. Chrysin is from the fruit of blue passionflower, a tropical vine. Oranges, grapefruit, lemons, and other citrus fruits are good sources of eriodicytol, hesperetin and naringenin. The ARS scientists showed, for the first time, that all six plant compounds target an enzyme known as TBK1. Each compound inhibits, to a greater or lesser extent, TBK1's ability to activate a specific biochemical signal. If unimpeded, the signal would lead to formation of gene products known to trigger inflammation in the body.
Details
For details, contact: Daniel Hwang, (530) 754-4838, Immunity and Disease Prevention Research Unit, ARS Western Human Nutrition Research Center, Davis, Calif.
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Studies led by ARS
molecular biologist Daniel H. Hwang are providing new information about
phytochemicals that inhibit TBK1, a signaling enzyme associated with
inflammation in the body
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Studies by scientists such as epidemiologist Chung-Jung Chiu (left) and biochemist Allen Taylor are showing that regularly eating a combination of protective nutrients and a low-glycemic-index diet may protect people from vision loss due to age-related macular degeneration.
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Agricultural Research Service (ARS)-funded scientists are finding that healthy eating not only can reduce health care costs, but also can mitigate vision loss due to age-related macular degeneration (AMD) and other sight-robbing diseases. One study indicated that regularly consuming a combination of protective nutrients and a low-glycemic-index, or "slow carb," diet provided an AMD-protective effect. The nutrients that were found to be most protective in combination with the low-glycemic-index diet were vitamins C and E, zinc, lutein, zeaxanthin, and the omega-3 fatty acids known as DHA and EPA.
Details
For details, contact: Allen Taylor, (617) 556-3156, Laboratory for Nutrition and Vision Research, Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Mass. |
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Using an advanced genetic screening technique, Agricultural Research Service (ARS) scientists and cooperators have detected, for the first time, more than 700 genes that give microbes like Salmonella and E. coli the ability to resist antibiotics and other antimicrobial compounds. The researchers used what is called DNA microarray technology to find the resistance genes in a wide variety of bacteria such as Salmonella, E. coli, Campylobacter, Listeria, and Enterococcus, among others. These organisms can cause food poisoning and are thus a major public health concern. Researchers are concerned that some of these organisms have acquired genetic resistance to the antibiotics used to kill them. Finding the genes that confer resistance is an important step for scientists looking for new ways to control these organisms. The ARS scientists selected about 1,000 unique genes from among 5,000 genes found in GenBank that included the words "antimicrobial resistance" in their description. Then they designed a microarray of more than 700 DNA probes to detect the resistance genes.
Details
For details, contact: Jonathan Frye, (706) 546-3677, Bacterial Epidemiology and Antimicrobial Resistance Research Unit, ARS Richard B. Russell Agricultural Research Center, Athens, Ga. |
ARS scientists and cooperators have detected more
than 700 genes that give microbes like Salmonella—shown
here—and E. coli the ability to resist antibiotics.
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ARS scientists have profiled the phytonutrient
contents of several hundred different potatoes, showing that the tubers can
vary widely in the level of various healthful compounds.
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New analytical procedures for rapidly detecting and measuring phytonutrient concentrations in potatoes have recently been devised by Agricultural Research Service (ARS) researchers and their colleagues. Using the new analytic methods, the researchers profiled the phytonutrient contents of several hundred lines of wild and cultivated potato. For example, their analysis of phytonutrients known as phenolics showed concentrations that ranged from 100 to more than 1,500 milligrams per 100 grams dry weight in the potatoes.
Details
For details, contact: Roy Navarre, (509) 786-9261, ARS Vegetable and Forage Crop Research Unit, Prosser, Wash. |
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Agricultural Research Service (ARS) scientists and their colleagues have developed a preliminary model that predicts an individual's vitamin D requirements. To develop the preliminary model, the scientists worked with 72 young adult volunteers who provided intermittent records of what they ate and, for 7- to 8-week stints, wore photosensitive badges from 7 a.m. to 7 p.m. so the scientists could determine their level of sun exposure. Data from the volunteers—either African-American or of European ancestry—who had relatively low amounts of sun exposure suggest that they may need additional vitamin D to reach a target blood level of 75 nanomoles of vitamin D per liter of plasma. However, the scientists cautioned that some vitamin D levels indicated by the model exceed the level currently considered safe. More research, with a larger number of volunteers, may refine the predictive power of the model.
Details
For details, contact: Charles B. Stephensen, (530) 754-9266, Immunity and Disease Prevention Research Unit, ARS Western Human Nutrition Research Center, Davis, Calif.
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ARS researchers have developed a preliminary model
that predicts an individual's vitamin D requirements based on diet, sun
exposure, and skin tone.
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A study by ARS-funded researchers has found that
senior citizens with sufficient levels of vitamin D also had better cognitive
performance on tests.
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Scientists funded by the Agricultural Research Service (ARS) have now contributed to the limited but growing body of evidence of a link between vitamin D and cognitive function. This study involved more than 1,000 participants receiving home care. The researchers evaluated associations between measured vitamin D blood concentrations and neuropsychological test results. Elders requiring home care have a higher risk of not getting enough vitamin D because of limited sunlight exposure and other factors. The participants, ages 65 to 99 years, were grouped by their vitamin D status, which was categorized as deficient, insufficient, or sufficient. Only 35 percent had sufficient vitamin D blood levels. Those participants had better cognitive performance on the tests than the participants in the vitamin D-deficient and insufficient categories, particularly on measures of "executive performance," such as cognitive flexibility, perceptual complexity, and reasoning. The associations persisted after taking into consideration other variables that could also affect cognitive performance.
Details
For details, contact: Katherine L. Tucker, (617) 556-3351, Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Mass. |
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A team of researchers, including one with the Agricultural Research Service (ARS), has found that phenolic components in olive oil actually modify genes that are involved in the inflammatory response. Volunteers were fed breakfasts containing virgin olive oil with either high-content phenolic compounds (398 parts per million) or low-content phenolic compounds (70 parts per million). The researchers tracked the expression of more than 15,000 human genes in blood cells during the after-meal period. The results indicated that 79 genes are turned down and 19 are turned up by the high-phenolic-content olive oil. Many of those genes have been linked to obesity, high blood-fat levels, type 2 diabetes and heart disease. Importantly, several of the turned-down genes are known promoters of inflammation, so those genes may be involved in "cooling off" inflammation that often accompanies metabolic syndrome. The researchers concluded that the results shed light on a molecular basis for reduced heart disease risk among people living in Mediterranean countries where virgin olive oil is the main source of dietary fats.
Details
For details, contact: Laurence D. Parnell, (617) 556-3089, Nutrition and Genomics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Mass. |
Phenolic compounds in olive oil were found to
positively modify genes involved in the inflammatory response, a team of
researchers, including one with ARS, reported.
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White button mushrooms were shown by nutritional immunologists Simin Meydani (left) and Dayong Wu to enhance the activity of critical cells in the body's immune system.
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Scientists funded by the Agricultural Research Service (ARS) have conducted an animal-model and cell-culture study showing that white button mushrooms enhanced the activity of critical cells in the body's immune system. In the United States, white button mushrooms represent 90 percent of the total mushrooms consumed. The study's cell-culture phase showed that white button mushrooms enhanced the maturity of immune system cells called "dendritic cells," from bone marrow. Dendritic cells can make T cells, which are important white blood cells that can recognize and eventually deactivate or destroy antigens on invading microbes. When immune system cells are exposed to disease-causing pathogens such as bacteria, the body begins to increase the number and function of immune system cells
Details
For details, contact: Simin N. Meydani, (617) 556-3129, Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Mass. |
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Twenty-eight genes that are involved in bulking up yellow perch—an important aquaculture fish in the Great Lakes region—have been discovered by Agricultural Research Service (ARS) scientists and their university colleagues. Usually, female perch grow faster than their male counterparts, a disparity that causes productivity losses because farmers have to sort out the smaller males. Also, the smaller males still need to be maintained on feed until they reach market size, delaying harvest and increasing production costs. In an indoor tank study, the researchers discovered the growth-linked genes by feeding perch standard diets supplemented with estrogen. Estrogen is not fed to fish in commercial production; the researchers only used it to trigger genes that control growth. After three months, the perch were much larger. Researchers then sequenced genes from the fish livers to better understand the actual molecular mechanisms by which estrogen promotes growth in males versus females.
Details
For details, contact: Brian Shepherd, (414) 382-1767, ARS Dairy Forage and Aquaculture Research Unit, Madison, Wis. |
ARS and university researchers have identified 28
genes that control how fast yellow perch, which are commercially farmed, put on
weight. Photo, USDA.
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ARS geneticist Phil Miklas has developed a new cranberry dry bean cultivar called Crimson that offers viral disease resistance and a high yield.
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"Crimson," a new cranberry dry bean cultivar, is now available for production in the form of foundation seed that could give rise to a new bumper crop of the colorful legume for 2010. "Crimson" was developed by Agricultural Research Service (ARS) scientists from a cross between the commercial cultivar "Cardinal" and the dry bean breeding line PS98-302-5-5. The combination of the two "parents" has endowed "Crimson" with viral disease resistance and a high yield of shapely, maroon-speckled seed. The seeds of "Crimson" are also beautiful on the inside: The new variety lacks a common but commercially unacceptable blemish called "black heart."
Details
For details, contact: Phillip N. Miklas, (509) 786-9258, ARS Vegetable and Forage Crop Research Unit, Prosser, Wash.
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