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.
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.
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.
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.
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.
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.
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.
For details, contact: Katherine L. Tucker, (617) 556-3351, Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Mass.
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.
For details, contact: Laurence D. Parnell, (617) 556-3089, Nutrition and Genomics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Mass.
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
For details, contact: Simin N. Meydani, (617) 556-3129, Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Mass.
"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."