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PubMed2001

Entrainment of the circadian clock in the liver by feeding.

Circadian rhythms of behavior are driven by oscillators in the brain that are coupled to the environmental light cycle. Circadian rhythms of gene expression occur widely in peripheral organs. It is unclear how these multiple rhythms are coupled together to form a coherent system. To study such coupling, we investigated the effects of cycles of food availability (which exert powerful entraining effects on behavior) on the rhythms of gene expression in the liver, lung, and suprachiasmatic nucleus (SCN). We used a transgenic rat model whose tissues express luciferase in vitro. Although rhythmicity in the SCN remained phase-locked to the light-dark cycle, restricted feeding rapidly entrained the liver, shifting its rhythm by 10 hours within 2 days. Our results demonstrate that feeding cycles can entrain the liver independently of the SCN and the light cycle, and they suggest the need to reexamine the mammalian circadian hierarchy. They also raise the possibility that peripheral circadian oscillators like those in the liver may be coupled to the SCN primarily through rhythmic behavior, such as feeding.

Animals↗
PubMed2004

Microbial detoxification of mycotoxin deoxynivalenol.

Deoxynivalenol (DON) is a trichothecene secondary metabolite produced by Fusarium species infecting cereal crops. As a mycotoxin, DON causes losses in livestock production and poses a health risk to humans consuming contaminated cereal products. DON also acts as a virulence factor, facilitating the colonization of host plants by Fusarium spp. Enzymatic detoxification of mycotoxins in feed additives and genetically modified crops is a promising approach for the reduction of mycotoxin contamination of feeds and food. A prerequisite for the development of biotechnological strategies for DON detoxification is the availability of genes encoding suitable enzymatic activities. With the goal of isolating microbial cultures that can be used as a source of such activities, we screened 1285 microbial cultures from farmland soil, cereal grains, insects and other sources for DON transformation under aerobic conditions. One mixed culture transformed DON into two chromatographically separable products. The main product of the transformation was purified and its structure was elucidated by mass spectroscopy, (1)H-NMR, (13)C-NMR and proton-proton and carbon-proton correlated NMR spectroscopy. The structure of this product was determined to be 3-keto-4-deoxynivalenol. The DON-transforming mixed culture survived and retained its transforming activity during a starvation period of six months at 20 degrees C. Transformation of DON was suppressed by low concentrations of glucose and high concentrations of tryptone and yeast extract. Cell-free supernatants obtained either by filtration through a 0.22 microm membrane filter or by centrifugation did not exert DON-transforming activity. Trichothecenes 15-acetyl-DON, 3-acetyl-DON and fusarenon-X were also transformed.

Aerobiosis↗
PubMed2005

Differential effects of glyphosate and roundup on human placental cells and aromatase.

Roundup is a glyphosate-based herbicide used worldwide, including on most genetically modified plants that have been designed to tolerate it. Its residues may thus enter the food chain, and glyphosate is found as a contaminant in rivers. Some agricultural workers using glyphosate have pregnancy problems, but its mechanism of action in mammals is questioned. Here we show that glyphosate is toxic to human placental JEG3 cells within 18 hr with concentrations lower than those found with agricultural use, and this effect increases with concentration and time or in the presence of Roundup adjuvants. Surprisingly, Roundup is always more toxic than its active ingredient. We tested the effects of glyphosate and Roundup at lower nontoxic concentrations on aromatase, the enzyme responsible for estrogen synthesis. The glyphosate-based herbicide disrupts aromatase activity and mRNA levels and interacts with the active site of the purified enzyme, but the effects of glyphosate are facilitated by the Roundup formulation in microsomes or in cell culture. We conclude that endocrine and toxic effects of Roundup, not just glyphosate, can be observed in mammals. We suggest that the presence of Roundup adjuvants enhances glyphosate bioavailability and/or bioaccumulation.

Adjuvants, Pharmaceutic↗
PubMed1993

The food safety of transgenic animals: implications from traditional breeding.

The genetic events associated with traditional selection have implications for the food safety of transgenic animals. Selection has been empirical, relying on the use of the best animals for breeding. Molecular techniques are now being used to identify the genes selected and to describe the differences between alleles that are important in selection to improve quantitative traits. The results of such analyses provide background details of the genetic and physiological effects of the traditional selection of animal lines. Examples of the kinds of genes that may be subject to selection are those coding for peptide hormones, steroid metabolic enzymes, the calcium-channel gating protein, and genes of the major histocompatibility complex. Unselected genes, sometimes with undesirable alleles, may be carried along as "hitchhikers" if they are closely linked to the selected gene. In spite of this potential for physiologically dangerous genetic changes in selected animals, hereditary food toxicity has never been associated with a selected line of the common food animals. This is probably because the allowable physiological range of results of selection is limited by the requirement for healthy, productive animals. Based on these limitations, foods from healthy transgenic animals produced for the purpose of herd improvement are likely to be as safe as the foods from the untransformed parental line. Animals are important indicators of their own food safety.

Animals↗
PubMed1997

Agronomic problems related to provitamin A carotenoid-rich plants.

OBJECTIVES: Review how agricultural systems might be changed to increase the vitamin A density of diets in developing countries to provide sustainable solutions to vitamin A deficiency globally. DESIGN: Develop agricultural systems that not only assure calorie adequacy for people, but also address vitamin A density in diets. SETTINGS: Agricultural systems could be modified in some developing nations in ways that would provide adequate dietary amounts of provitamin A carotenoids from plant food sources. SUBJECTS: Infants and children of low-income families are most at risk of developing vitamin A deficiency in developing countries. INTERVENTIONS: Cropping systems could be modified to include more vegetable and fruit crops containing higher bioavailable amounts of provitamin A carotenoids in some countries. Additionally, cultural practices could be modified through education, agricultural extension and/or social marketing to insure that the bioavailable provitamin A carotenoid levels in food crops are optimized. Staple food crops could be improved as sources of provitamin A carotenoids by traditional plant breeding and/or by genetic engineering efforts. RESULTS: Currently, many techniques are available to increase the vitamin A content of diets through sustainable food-based approaches. Agricultural approaches should be examined closely to finding sustainable food-based system solutions to vitamin A deficiency globally. CONCLUSIONS: The world community should strive to find food-based system approaches to eliminating vitamin A deficiency. Modifying agricultural systems in ways that will not only maximizing food production, but also insure nutritional adequacy of vitamin A is a desirable goal for many developing countries.

Agriculture↗
PubMed2006

Review: Genetically modified plants for the promotion of human health.

Plants are attractive biological resources because of their ability to produce a huge variety of chemical compounds, and the familiarity of production in even the most rural settings. Genetic engineering gives plants additional characteristics and value for cultivation and post-harvest. Genetically modified (GM) plants of the "first generation" were conferred with traits beneficial to producers, whereas GM plants in subsequent "generations" are intended to provide beneficial traits for consumers. Golden Rice is a promising example of a GM plant in the second generation, and has overcome a number of obstacles for practical use. Furthermore, consumer-acceptable plants with health-promoting properties that are genetically modified using native genes are being developed. The emerging technology of metabolomics will also support the commercial realization of GM plants by providing comprehensive analyzes of plant biochemical components.

Carotenoids↗
PubMedDate not supplied

Are genetically modified plants useful and safe?

So far, plants have been genetically modified essentially to achieve resistance to herbicides, or to pathogens (mainly insects, or viruses), but resistance to abiotic stresses (such as cold, heat, drought, or salt) is also being studied. Genetically modified (GM) plants with improved nutritional qualities have more recently been developed, such as plants containing higher proportions of unsaturated fatty acids (omega-3 and omega-6) in their oil (to prevent cardio-vascular diseases), or containing beta-carotene as in the golden rice (to prevent vitamin A deficiency). Possible risks for human health (such as the production of allergenic proteins), or for the environment (such as the appearance of superweeds as a result from gene flow), should be carefully studied, and a science-based assessment of benefits vs. risks should be made on a case by case basis, both for GM plants and for plants obtained by conventional breeding methods.

Animals↗
PubMed2000

Temporal and spatial adaptation to food restriction in mice under naturalistic conditions.

Free-living female laboratory mice, adapted to outdoor life in large pens providing a naturalistic environment, were tested for their ability to modify their foraging habits to controlled food supply. An automatic feeder box delivered a small portion of the daily quantity of seeds to each individual mouse. Eight such boxes were placed into an outdoor pen. Each day, mice had to visit all boxes to gather the daily amount of food and were rewarded only at the first visit to each box. Mice were individually recognised by an implanted microchip. Throughout a 16-day period, feeding activity concentrated in an interval time around the beginning of the daily session. During the same period, the number of different feeders visited every day by mice increased irrespective of variation in exploratory activity. The experimental set-up allowed detecting temporal and spatial adaptations to the food restriction, as well as behavioural differences due to territorial and social factors. These data permit the design of novel tests assessing behavioural changes, memory and learning in normal and genetically modified mice, both in the laboratory and in naturalistic settings.

Adaptation, Psychological↗
PubMed2004

Method for the detection of synthetic cry3A in transgenic potatoes.

All transgenic cultivars of potatoes registered in Canada and the United States have been modified to express a synthetic cry3A gene as a means of conferring resistance against the Colorado potato beetle, an important economic pest of potatoes. A PCR method was developed to amplify a 499 bp region of the synthetic cry3A gene. Using this method, synthetic cry3A could be detected in six different transgenic cultivars. Positive results could be confirmed with PvuII restriction digestion of the PCR-generated amplicon, which resulted in two fragments that were 283 and 216 bp in size. Of the 52 tuber extracts tested with this method, no false positive or false negative results were obtained, suggesting the method could be used with a high degree of accuracy. The absolute limit of detection was the number of cry3A copies present in one or perhaps two haploid copies of the potato genome. The practical limit of detection in tubers on a fresh weight basis was 0.02% for the NL 10-SUP and 0.01% for the remaining cultivars. Synthetic cry3A could also be detected in processed food products such as potato chips, shoestring potatoes, and frozen French fries. The method was suitable for screening potato tuber lots and some processed foods for the presence of synthetic cry3A.

Animals↗
PubMed2001

A Gr receptor is required for response to the sugar trehalose in taste neurons of Drosophila.

We recently identified from the Drosophila genome database a large family of G protein-coupled receptor genes, the Gr genes, and predicted that they encode taste receptors on the basis of their structure and specificity of expression. The expression of Gr genes in gustatory neurons has subsequently been confirmed and 56 family members have been reported. Here we provide functional evidence that one Gr gene, Gr5a, encodes a taste receptor required for response to the sugar trehalose. In two different mutants that carry deletions in Gr5a, electrophysiological and behavioral responses to trehalose were diminished but the response to sucrose was unaffected. Transgenic rescue experiments showed that Gr5a confers response to trehalose. The results correlate a particular taste ligand with a Gr receptor and indicate a role for G protein-mediated signaling in the transduction of sweet taste in Drosophila.

Action Potentials↗
PubMed2005

[Confinement and consumption of cloned and transgenic animals].

Reproduction by cloning can eliminate some of the problems inherent to sexual reproduction, but it creates others. The genetic heritage of nucleus donor cells and the genetic status of clones are not precisely known. Furthermore, reprogramming of the genome of nucleus donor cells by the ovocyte cytoplasm is often incomplete. Animals obtained through cloning are thus essentially genetically identical to their genitors, but they are often epigenetically modified, with unpredictable effects. Transgenesis results in most cases from the addition to a genome of one or more known genes. The direct and indirect effects of transgenesis cannot all be predicted. Specific confinement measures make it possible to raise animals in high-security conditions, preventing their dissemination in the human food chain, in animal feed or in the environment. The toxicity, allergenicity and infectiousness of cloned ortransgenic animals can be evaluated by means of tests.

Animals↗
PubMed2006

Novel foods to treat food allergy and gastrointestinal infection.

The gastrointestinal tract communicates directly with the external environment. Necessary nutrients must be absorbed and commensal bacteria tolerated, and foreign proteins, antigens, and pathogens must be simultaneously excluded or destroyed. Immaturity or disruption of the mucosal immune defenses increases vulnerability to food allergy, intolerance, and infectious disease. Diseases resulting from ingested foreign proteins and organisms are increasing and cause morbidity and mortality worldwide. There is no specific treatment for food allergy other than avoidance. Vaccination for infectious disease is limited by the cost and logistics of distribution and administration, particularly in developing countries. Novel strategies are being explored to modulate the gut mucosal immune system by altering protein expression in food. Crops are being developed to remove deleterious allergens to prevent immunogenic exposure while preserving nutritional quality. Local food plants that express protein fragments of pathogens might provide an effective means to stimulate gut mucosal immunity while increasing vaccine accessibility.

Food Hypersensitivity↗
PubMed1985

Genetic toxicology in the food industry.

In vitro testing of food products for mutagenic activity presents particular problems, especially in connection with the administration of the test material to the assay system, the possible interference of food components with the genetic end-point used for the assay, the presence in foods of various factors that may modify mutagenic activity, the identification of appropriate negative or positive controls and the avoidance of artefactual mutagen formation during the preparation of test samples. Ideally mutagenicity testing requires in vivo studies (although these too have particular problems when applied to foods) but, at present, in vitro tests provide the only practical means of screening large numbers of food samples or modifying factors and of assessing food-processing techniques. The tests can be carried out on model systems (e.g. amino acid/sugar mixtures), on isolated and purified constituents of foods, on fractionated solvent extracts or on whole-food homogenates subjected to digestion procedures. However, to determine genotoxic risk from foodstuffs, quantitative data from mammalian in vivo tests and from human consumption and metabolism studies are also required.

Animals↗
PubMed2006

The cyanogenic glucoside composition of Zygaena filipendulae (Lepidoptera: Zygaenidae) as effected by feeding on wild-type and transgenic lotus populations with variable cyanogenic glucoside profiles.

Zygaena larvae sequester the cyanogenic glucosides linamarin and lotaustralin from their food plants (Fabaceae) as well as carry out de novo biosynthesis of these compounds. In this study, Zygaena filipendulae were reared on wild-type Lotus corniculatus and wild-type and transgenic L. japonicus plants with differing content and ratios of the cyanogenic glucosides linamarin and lotaustralin and of the cyanoalkenyl glucosides rhodiocyanoside A and D. LC-MS analyses, free choice feeding experiments and developmental studies were used to examine the effect of varying content and ratios of these secondary metabolites on the feeding preferences, growth and development of Z. filipendulae. Larvae reared on cyanogenic L. corniculatus developed faster compared to larvae reared on L. japonicus although free choice feeding trials demonstrated that the latter plant source was the preferred food plant. Larvae reared on acyanogenic L. corniculatus showed decelerated development. Analysis of different life stages and tissues demonstrate that Z. filipendulae strive to maintain certain threshold content and ratios of cyanogenic glucosides regardless of the composition of the food plants. Despite this, the ratios of cyanogenic glucosides in Z. filipendulae remain partly affected by the ratio of the food plant due to the high proportion of sequestering that takes place.

Animals↗
PubMed1999

Potato hash.

Explore the source record for details and available documents.

Animals↗
PubMed2006

Improving potato storage and processing characteristics through all-native DNA transformation.

The dominant potato (Solanum tuberosum) variety for French fry production in the United States is the 131-year-old Russet Burbank. Market penetration of the higher yielding and more uniform Ranger Russet variety is limited to about one-fifth of that of the Russet Burbank because of two storage deficits: black spot bruise sensitivity and high levels of cold-induced sweetening. Here, these trait weaknesses are turned into strengths by simultaneously lowering the expression of Ranger Russet's tuber-expressed polyphenol oxidase (Ppo), starch-associated R1, and phosphorylase-L (PhL) genes. This genetic modification was accomplished without inserting any foreign DNA into the plant genome. French fries from the intragenic potatoes also contained reduced amounts of the antinutritional compound acrylamide while, unexpectedly, displaying enhanced sensory characteristics.

DNA, Plant↗