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United States Department of Agriculture

Agricultural Research Service

Food & Nutrition Research Briefs

Table place setting with apple. Title: Food and Nutrition Research Briefs. Link to FNRB home page

October 2010


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Contents

Luteolin Stars in Study of Healthful Plant Compounds

Vitamin D and Mental Agility in Elders

Nutrition's Potential to Save Sight

Molecular Biology Provides Clues to Health Benefits of Olive Oil

Genetic Screening Technique Can Detect More Than 700 Antimicrobial-Resistance Genes

Researchers Study Benefits of White Button Mushrooms

New Methods Developed to Detect and Measure Potato Phytonutrients

ARS Scientists and Their Cooperators Find Genes Involved in Yellow Perch Growth

Model Predicts Individual's Vitamin D Needs

Bright New Dry Bean for Salads and Other Foods

 

 


Luteolin Stars in Study of Healthful Plant Compounds

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.

Photo: ARS molecular biologist Daniel H. Hwang studies scans of receptors involved in inflammation. Link to photo information
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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Photo: Epidemiologist Chung-Jung Chiu (left) and biochemist Allen Taylor review a close up image of the retina of a patient with macular degeneration. Link to photo information
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.

Nutrition's Potential to Save Sight

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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Genetic Screening Technique Can Detect More Than 700 Antimicrobial-Resistance Genes

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.

Photo: Salmonella bacteria colony. Link to photo information
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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Photo: Different kinds of potatoes. Link to photo information
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.

New Methods Developed to Detect and Measure Potato Phytonutrients

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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Model Predicts Individual's Vitamin D Needs

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.

Photo: A group of five young adults.
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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Photo: Two older men at a table.
A study by ARS-funded researchers has found that senior citizens with sufficient levels of vitamin D also had better cognitive performance on tests.

Vitamin D and Mental Agility in Elders

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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Molecular Biology Provides Clues to Health Benefits of Olive Oil

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.

Photo: Olive oil.
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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Photo: ARS nutritional immunologists Simin Meydani (left) and Dayong Wu review data generated from a gamma counter. Link to photo information
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.

Researchers Study Benefits of White Button Mushrooms

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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ARS Scientists and Their Cooperators Find Genes Involved in Yellow Perch Growth


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.

Photo: Two yellow perch swimming.
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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Photo: ARS geneticist Phil Miklas exams bean plants.Link to photo information
ARS geneticist Phil Miklas has developed a new cranberry dry bean cultivar called Crimson that offers viral disease resistance and a high yield.

Bright New Dry Bean for Salads and Other Foods

"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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Last Modified: 1/26/2011