SEARCH · PubMed Health

Results for “Food, Genetically Modified”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,693 records · Page 94Linked to original sources

PubMed2002

Plant toxic proteins with insecticidal properties. A review on their potentialities as bioinsecticides.

To meet the demands for food of the expanding world population, there is need of new ways for protecting plant crops against predators and pathogens while avoiding the use of environmentally aggressive chemicals. A milestone in this field was the introduction into crop plants of genes expressing Bacillus thuringiensis entomotoxic proteins. In spite of the success of this new technology, however, there are difficulties for acceptance of these 'anti-natural' products by the consumers and some concerns about its biosafety in mammals. An alternative could be exploring the plant's own defense mechanisms, by manipulating the expression of their endogenous defense proteins, or introducing an insect control gene derived from another plant. This review deals with the biochemical features and mechanisms of actions of plant proteins supposedly involved in defense mechanisms against insects, including lectins, ribosome-inactivating proteins, enzymes inhibitors, arcelins, chitinases, ureases, and modified storage proteins. The potentialities of genetic engineering of plants with increased resistance to insect predation relying on the repertoire of genes found in plants are also discussed. Several different genes encoding plant entomotoxic proteins have been introduced into crop genomes and many of these insect resistant plants are now being tested in field conditions or awaiting commercialization.

Amino Acid Sequence↗

PubMed2005

Property rights and genetic engineering: developing nations at risk.

Eighty percent of (commercial) genetically engineered seeds (GES) are designed only to resist herbicides. Letting farmers use more chemicals, they cut labor costs. But developing nations say GES cause food shortages, unemployment, resistant weeds, and extinction of native cultivars when "volunteers" drift nearby. While GES patents are reasonable, this paper argues many patent policies are not. The paper surveys GE technology, outlines John Locke's classic account of property rights, and argues that current patent policies must be revised to take account of Lockean ethical constraints. After answering a key objection, it provides concrete suggestions for implementing its ethical conclusions.

Bioethics↗

PubMed2004

Alcohol, nutrition and health maintenance: selected aspects.

In view of the developments in health care relating to the increased prevalence and incidence of chronic diseases and the continuing increase in health-care expenditure, more attention should be paid to health maintenance and disease prevention. Any strategy that can influence health maintenance is of interest, especially lifestyle factors such as nutrition, exercise or stress control. Alcohol has an important place in the daily life of many healthy as well as sick individuals. Alcohol has three major characteristics; it is a nutrient (energy source), a psycho-active drug and a toxin. Each consumer has the choice of which of the characteristics of alcohol he/she wants to utilise. Thus, alcohol represents one of the most important self-implemented disease modifiers in our modern society. The major determinants of the health effects of alcohol are the absolute amount consumed, the consumption frequency, associated lifestyle factors (e.g. smoking, nutrient intake, substrate composition, physical activity pattern) and last, but not least, the genetic background. There are few known disease conditions that have not already been associated positively or negatively with alcohol consumption. The list of diseases includes atherosclerosis, dementia, diabetes, obesity and conditions relating to Zn metabolism. Obesity represents the most important disease modifier in the world and the prevalence rates are increasing rapidly. Evidence suggests that alcohol represents a risk factor for overweight and obesity as a result of specific effects on energy metabolism and substrate metabolism. The potential role of alcohol as an important modulator for the postprandial lipidaemia and its role in the pathogenesis of modern diseases will be discussed.

Alcohol Drinking↗

PubMed2001

Fats and fatty acids as growth factors for Lactobacillus delbrueckii.

The effects of various fats and fatty acids on the growth of Lactobacillus delbrueckii strains have been studied using modified MRS broth without Tween 80 as a basic growth medium. Among the six L. delbrueckii strains studied all except one strain required Tween 80 or Tween 20 as a fatty acid supplement for the growth. Tween 40 and Tween 60, which contain solely medium and long chain saturated fatty acids, inhibited the growth of all L. delbrueckii strains when present as a sole fat supplement in MRS broth. Free oleic acid but not free lauric acid could substitute Tween 80 or Tween 20 supplement suggesting that unsaturated fatty acids are essential growth factors for most L. delbrueckii strains. Among the natural food oils tested, the oils containing the lowest amounts of saturated long chain fatty acids promoted the growth of L. delbrueckii most effectively. Especially cellular C18:1 and C19 cyclopropane fatty acid contents of L. delbrueckii were strongly affected by exogenous fatty acid composition and by strain suggesting genetic diversity and polymorphism among the genes encoding and/or regulating cyclopropane synthase. In addition obviously most if not all L. delbrueckii strains lack particular synthase, desaturase and/or dehydrase activities required for de novo synthesis of long chain unsaturated fatty acids. These biochemical features could be used as informative chemotaxonomic characteristics for L. delbrueckii starter strain identification and selection.

Fatty Acids↗

PubMed2005

Inter-population variation of carotenoids in Galápagos land iguanas (Conolophus subcristatus).

Carotenoids have received much attention from biologists because of their ecological and evolutionary implications in vertebrate biology. We sampled Galápagos land iguanas (Conolophus subcristatus) to investigate the types and levels of blood carotenoids and the possible factors affecting inter-population variation. Blood samples were collected from populations from three islands within the species natural range (Santa Cruz, Isabela, and Fernandina) and one translocated population (Venecia). Lutein and zeaxanthin were the predominant carotenoids found in the serum. In addition, two metabolically modified carotenoids (anhydrolutein and 3'-dehydrolutein) were also identified. Differences in the carotenoid types were not related to sex or locality. Instead, carotenoid concentration varied across the localities, it was higher in females, and it was positively correlated to an index of body condition. Our results suggest a possible sex-related physiological role of xanthophylls in land iguanas. The variation in the overall carotenoid concentration between populations seems to be related to the differences in local abundance and type of food within and between islands.

Animals↗

PubMed2006

Results of a 90-day safety assurance study with rats fed grain from corn borer-protected corn.

The results of a 90-day rat feeding study with grain from MON 810 corn (YieldGard Cornborer -- YieldGard Cornborer is a registered trademark of Monsanto Technology, LLC) that is protected against feeding damage from corn and stalk boring lepidopteran insects are presented. Corn borer protection was accomplished through the introduction of cry1Ab coding sequences into the corn genome for in planta production of a bioactive form of Cry1Ab protein. Grain from MON 810 and its near-isogenic control was separately formulated into rodent diets at levels of 11% and 33% (w/w) by Purina Mills, Inc. (PMI). All diets were nutritionally balanced and conformed to PMI specifications for Certified LabDiet (PMI Certified LabDiet 5002 is a registered trademark of Purina Mills, Inc.) 5002. There were a total of 400 rats in the study divided into 10 groups of 20 rats/sex/group. The responses of rats fed diets containing MON 810 were compared to those of rats fed grain from conventional corn varieties. Overall health, body weight, food consumption, clinical pathology parameters (hematology, blood chemistry, urinalysis), organ weights, and gross and microscopic appearance of tissues were comparable between groups fed diets containing MON 810 and conventional corn varieties. This study complements extensive agronomic, compositional and farm animal feeding studies with MON 810 grain, confirming that it is as safe and nutritious as grain from existing commercial corn varieties.

Animals↗

PubMed2006

Food-processing enzymes from recombinant microorganisms--a review.

Enzymes are commonly used in food processing and in the production of food ingredients. Enzymes traditionally isolated from culturable microorganisms, plants, and mammalian tissues are often not well-adapted to the conditions used in modern food production methods. The use of recombinant DNA technology has made it possible to manufacture novel enzymes suitable for specific food-processing conditions. Such enzymes may be discovered by screening microorganisms sampled from diverse environments or developed by modification of known enzymes using modern methods of protein engineering or molecular evolution. As a result, several important food-processing enzymes such as amylases and lipases with properties tailored to particular food applications have become available. Another important achievement is improvement of microbial production strains. For example, several microbial strains recently developed for enzyme production have been engineered to increase enzyme yield by deleting native genes encoding extracellular proteases. Moreover, certain fungal production strains have been modified to reduce or eliminate their potential for production of toxic secondary metabolites. In this article, we discuss the safety of microorganisms used as hosts for enzyme-encoding genes, the construction of recombinant production strains, and methods of improving enzyme properties. We also briefly describe the manufacture and safety assessment of enzyme preparations and summarize options for submitting information on enzyme preparations to the US Food and Drug Administration.

Animals↗

PubMed2005

Familial Parkinson mutant alpha-synuclein causes dopamine neuron dysfunction in transgenic Caenorhabditis elegans.

Mutations in alpha-synuclein gene cause familial form of Parkinson disease, and deposition of wild-type alpha-synuclein as Lewy bodies occurs as a hallmark lesion of sporadic Parkinson disease and dementia with Lewy bodies, implicating alpha-synuclein in the pathogenesis of Parkinson disease and related neurodegenerative diseases. Dopamine neurons in substantia nigra are the major site of neurodegeneration associated with alpha-synuclein deposition in Parkinson disease. Here we establish transgenic Caenorhabditis elegans (TG worms) that overexpresses wild-type or familial Parkinson mutant human alpha-synuclein in dopamine neurons. The TG worms exhibit accumulation of alpha-synuclein in the cell bodies and neurites of dopamine neurons, and EGFP labeling of dendrites is often diminished in TG worms expressing familial Parkinson disease-linked A30P or A53T mutant alpha-synuclein, without overt loss of neuronal cell bodies. Notably, TG worms expressing A30P or A53T mutant alpha-synuclein show failure in modulation of locomotory rate in response to food, which has been attributed to the function of dopamine neurons. This behavioral abnormality was accompanied by a reduction in neuronal dopamine content and was treatable by administration of dopamine. These phenotypes were not seen upon expression of beta-synuclein. The present TG worms exhibit dopamine neuron-specific dysfunction caused by accumulation of alpha-synuclein, which would be relevant to the genetic and compound screenings aiming at the elucidation of pathological cascade and therapeutic strategies for Parkinson disease.

Animals↗

PubMed1998

Physical activity, genetic, and nutritional considerations in childhood weight management.

Almost one-quarter of U.S. children are now obese, a dramatic increase of over 20% in the past decade. It is intriguing that the increase in prevalence has been occurring while overall fat consumption has been declining. Body mass and composition are influenced by genetic factors, but the actual heritability of juvenile obesity is not known. A low physical activity (PA) is characteristic of obese children and adolescents, and it may be one cause of juvenile obesity. There is little evidence, however, that overall energy expenditure is low among the obese. There is a strong association between the prevalence of obesity and the extent of TV viewing. Enhanced PA can reduce body fat and blood pressure and improve lipoprotein profile in obese individuals. Its effect on body composition, however, is slower than with low-calorie diets. The three main dietary approaches are: protein sparing modified fast, balanced hypocaloric diets, and comprehensive behavioral lifestyle programs. To achieve long-standing control of overweight, one should combine changes in eating and activity patterns, using behavior modification techniques. However, the onus is also on society to reduce incentives for a sedentary lifestyle and over-consumption of food. To address the key issues related to childhood weight management, the American College of Sports Medicine convened a Scientific Roundtable in Indianapolis.

Adolescent↗

PubMed2004

The genetics and properties of cereal ribosome-inactivating proteins.

Plants contain proteins that are capable of inactivating ribosomes, commonly referred to as Ribosome Inactivating Proteins (RIPs). These particular plant proteins have received attention in biological and biomedical research because of their unique biological activities towards animals and human cells as cell-killing agents. Some of the best-characterised RIPs have been isolated from exotic plants, but they have also been found in cereals and other food crops. Cereals contain, in general, RIPs in the endosperm protein pool: they share a high similarity with all the other RIPs retaining, however, characteristic features forming a distinct class which diversified significantly during evolution. They appear to be involved in quite different physiological roles, such as defence against pathogens and/or involved in regulatory and developmental processes. This review aims to provide a critical assessment to work related to cereal RIP with particular emphasis to the maize RIPs.

Edible Grain↗

PubMed2005

An antioxidant system required for host protection against gut infection in Drosophila.

A fundamental question that applies to all organisms is how barrier epithelia efficiently manage continuous contact with microorganisms. Here, we show that in Drosophila an extracellular immune-regulated catalase (IRC) mediates a key host defense system that is needed during host-microbe interaction in the gastrointestinal tract. Strikingly, adult flies with severely reduced IRC expression show high mortality rates even after simple ingestion of microbe-contaminated foods. However, despite the central role that the NF-kappaB pathway plays in eliciting antimicrobial responses, NF-kappaB pathway mutant flies are totally resistant to such infections. These results imply that homeostasis of redox balance by IRC is one of the most critical factors affecting host survival during continuous host-microbe interaction in the gastrointestinal tract.

Animals↗

PubMed2005

Plant-derived vaccines against diarrheal diseases.

Transgenic plants present a novel system for both production and oral delivery of vaccine antigens. Production of protein antigen in food plants is substantially cheaper than production in bacterial, fungal, insect cell, or mammalian cell culture. Edible plants themselves can also serve as the oral vaccine delivery system. Phase-1 studies of raw transgenic potatoes expressing the B subunit of Escherichia coli heat labile enterotoxin (LT-B), potatoes expressing Norwalk virus capsid protein, and defatted corn germ meal expressing LT-B have been conducted. New oral vaccines based on other transgenic plants will soon be evaluated in humans.

Animals↗

PubMed2006

Effect of corn hybrids expressing the coleopteran-specific cry3Bb1 protein for corn rootworm control on aboveground insect predators.

Field and laboratory studies were conducted to determine the effect of transgenic Bacillus thuringiensis (Bt) corn, Zea mays L. (YieldGard Rootworm), expressing the Cry3Bb1 protein on aboveground nontarget insect predators (minute pirate bug, ladybird beetles, and carabids). Visual counts of adult and immature Orius insidiosus (Say), Coleomegilla maculata (DeGeer), Hippodamia convergens Gurin-Meneville, and Scymnus spp. occurring in Bt corn and its non-Bt isoline were made at Manhattan, KS, in 2002 and at Manhattan and Scandia, KS, in 2003. No significant differences were found between the Bt corn and non-Bt isoline plots in the abundance (number per plant) of O. insidiosus, C. maculata, H. convergens, and Scymnus spp. Field predation on Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) egg masses was also observed during the silking stage of corn at Manhattan and Scandia in 2003. No significant differences were observed among treatments in predation rate for predators with chewing versus sucking mouthparts. Two laboratory studies determined the effect of Cry3Bb1 protein expressed in Bt corn pollen on C. maculata and carabids. The larvae of C. maculata were reared on Bt pollen, non-Bt pollen, or greenbugs, Schizaphis graminum (Rondani). The duration of larval and pupal stages, developmental time from egg hatch to adult emergence, percentage of survival, and elytra length were compared among treatments. There were no significant differences in developmental time of larvae fed pollen or greenbugs during their first two instars. However, significantly prolonged development of the third (1 d) and fourth instars (2 d) was observed for larvae fed greenbugs only. Total time for larval development was significantly longer for larvae that fed on greenbugs versus larvae fed on pollen. No significant differences were observed among treatments in the percentage of larvae that pupated or pupal stage duration. Larvae that fed on greenbugs had higher pupal and adult weights compared with pollen-fed larvae. However, pupal and adult weights did not vary between the Bt and non-Bt pollen treatments. No significant differences occurred in longevity and elytra length of beetles among all treatments. Two carabid species, Harpalus caliginosus F. and Harpalus pensylvanicus DeGeer, were reared on moistened dog food sprinkled with Bt or non-Bt corn pollen. No significant differences in mortality of H. caliginosus and H. pensylvanicus were detected among any of the treatments. There was no significant effect of Bt pollen on fecundity and egg viability of H. caliginosus. Our studies showed that YieldGard Rootworm had no effect on the selected coleopteran predators; therefore, this Bt corn hybrid could be used in an integrated pest management system.

Animals↗

PubMed2003

A nutrient sensor mechanism controls Drosophila growth.

Organisms modulate their growth according to nutrient availability. Although individual cells in a multicellular animal may respond directly to nutrient levels, growth of the entire organism needs to be coordinated. Here, we provide evidence that in Drosophila, coordination of organismal growth originates from the fat body, an insect organ that retains endocrine and storage functions of the vertebrate liver. In a genetic screen for growth modifiers, we identified slimfast, a gene that encodes an amino acid transporter. Remarkably, downregulation of slimfast specifically within the fat body causes a global growth defect similar to that seen in Drosophila raised under poor nutritional conditions. This involves TSC/TOR signaling in the fat body, and a remote inhibition of organismal growth via local repression of PI3-kinase signaling in peripheral tissues. Our results demonstrate that the fat body functions as a nutrient sensor that restricts global growth through a humoral mechanism.

Amino Acid Transport Systems↗

PubMed1998

Natural variation in a neuropeptide Y receptor homolog modifies social behavior and food response in C. elegans.

Natural isolates of C. elegans exhibit either solitary or social feeding behavior. Solitary foragers move slowly on a bacterial lawn and disperse across it, while social foragers move rapidly on bacteria and aggregate together. A loss-of-function mutation in the npr-1 gene, which encodes a predicted G protein-coupled receptor similar to neuropeptide Y receptors, causes a solitary strain to take on social behavior. Two isoforms of NPR-1 that differ at a single residue occur in the wild. One isoform, NPR-1 215F, is found exclusively in social strains, while the other isoform, NPR-1 215V, is found exclusively in solitary strains. An NPR-1 215V transgene can induce solitary feeding behavior in a wild social strain. Thus, isoforms of a putative neuropeptide receptor generate natural variation in C. elegans feeding behavior.

Amino Acid Sequence↗

PubMed1990

Enhancement of immune status by high levels of dietary vitamin B-6 without growth inhibition of human malignant melanoma in athymic nude mice.

The effects of dietary vitamin B-6 supplementation on the development of human malignant melanoma (M21-HPB) xenografts and on in vitro responses of leukocytes were examined. Male athymic nude mice, five weeks old, were divided into two groups of 48 each and fed 20% casein diets containing pyridoxine (PN) at 4.1 (control diet) and 61.6 mg/kg diet for 10 weeks. After four weeks of dietary treatment, 20 animals from each dietary group were injected subcutaneously with 3 x 10(7) melanoma cells. After 4, 8, and 10 weeks of dietary regimen, animals from each group were killed and blood, liver, and spleen samples were obtained. Food consumption and mouse body weights were similar between groups, and no difference was noted in tumor incidence or volume. Noninjected and tumor-bearing mice given the PN 61.6 diet generally exhibited greater oxygen radical production by phagocytic cells from blood and spleen than did animals fed the PN 4.1 diet. Spleen and blood B lymphocyte proliferation in response to lipopolysaccharide (LPS) was enhanced (10 and 30%) in the noninjected animals given the PN 61.6 diet. In addition, tumor-bearing mice fed the PN 61.6 diet had significantly greater LPS-induced spleen cell proliferation at eight weeks when compared with mice consuming the PN 4.1 diet. Despite immune enhancement, tumor incidence and progression was not modified by a high level of dietary vitamin B-6. Therefore, it is tempting to speculate that tumor inhibition by high dietary vitamin B-6 may be mediated by T lymphocyte-dependent mechanisms that are lacking in these genetically immuno-deficient mice.

Animals↗

PubMed2000

Diet effects on weight gain and body composition in high growth (hg/hg) mice.

Nongenetic factors such as nutrition modulate the effects of genes responsible for overgrowth in animals. The goal of this study was to examine the importance of genotype x diet interactions on the effects of a major locus that regulates growth in the mouse. We have examined the phenotype of high growth (hg), a partially recessive autosomal locus that increases growth rate and mature body size. C57BL/6J (C57) and congenic C57BL/6J-hg/hg (HG) mice were fed three experimental diets differing in protein and energy content from 3 to 12 wk of age. HG mice grew faster and were, on average, 51% heavier than C57 at 12 wk of age. Feed intake was higher in HG mice but proportional to the increase in body weight. The magnitude of the differences in body size and composition between lines depended on the interaction between genotype and the protein/energy ratio of the diet. In C57, the diets modified the level of fatness without changing adult lean mass. However, in HG the diets differentially affected both linear growth and body composition. In general, HG had higher plasma levels of insulin-like growth factor I at 3 and 12 wk than C57. Plasma insulin did not differ between lines, but leptin was higher for C57 mice fed a high-energy diet. These results show that the effects of hg on growth are modulated by diet composition. Therefore, this mutation could be a valuable model with which to study the genetic and nutritional aspects of overgrowth disorders.

Animals↗

PubMed2002

Regulated disruption of inositol 1,4,5-trisphosphate signaling in Caenorhabditis elegans reveals new functions in feeding and embryogenesis.

Inositol 1,4,5-trisphosphate (IP(3)) is an important second messenger in animal cells and is central to a wide range of cellular responses. The major intracellular activity of IP(3) is to regulate release of Ca(2+) from intracellular stores through IP(3) receptors (IP(3)Rs). We describe a system for the transient disruption of IP(3) signaling in the model organism Caenorhabditis elegans. The IP(3) binding domain of the C. elegans IP(3)R, ITR-1, was expressed from heat shock-induced promoters in live animals. This results in a dominant-negative effect caused by the overexpressed IP(3) binding domain acting as an IP(3) "sponge." Disruption of IP(3) signaling resulted in disrupted defecation, a phenotype predicted by previous genetic studies. This approach also identified two new IP(3)-mediated processes. First, the up-regulation of pharyngeal pumping in response to food is dependent on IP(3) signaling. RNA-mediated interference studies and analysis of itr-1 mutants show that this process is also IP(3)R dependent. Second, the tissue-specific expression of the dominant-negative construct enabled us to circumvent the sterility associated with loss of IP(3) signaling through the IP(3)R and thus determine that IP(3)-mediated signaling is required for multiple steps in embryogenesis, including cytokinesis and gastrulation.

Animals↗