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PubMed2005

Quantitative determination of Roundup Ready soybean (Glycine max) extracted from highly processed flour.

Roundup Ready soybean powder has been subjected to different amounts of DNA fragmentation to assess the accuracy of real-time PCR on processed food. Certified reference material (CRM) containing 10 g kg(-1) of Roundup Ready soybean (ERM-BF410d) prepared by a dry-mixing processing method was exposed to water at two temperatures, using three different mixing devices, or to baking temperature (250 degrees C) for 30 min. The amount of DNA extracted from the different samples was quantified by fluorimetry. The amount of fragmentation of the extracted DNA was characterised by gel and capillary electrophoresis and the percentage of genetically modified (GM) soybean was determined by a double quantitative real-time PCR method. Measurement of the event GTS 40-3-2 (RUR) was possible in all the treated materials, because small amplicons were amplified. Correct RUR percentages could be measured for intact powders with little or no DNA fragmentation. For samples with a high level of DNA degradation, however, the accuracy of the measurement was found to depend on the method used for DNA extraction. Genomic DNA isolated by use of silica resin resulted in statistically significant overestimation of the amount of GM.

DNA↗

PubMed2005

Baculoviruses-- re-emerging biopesticides.

Biological control of agricultural pests has gained importance in recent years due to increased pressure to reduce the use of agrochemicals and their residues in the environment and food. Viruses of a few families are known to infect insects but only those belonging to the highly specialized family Baculoviridae have been used as biopesticides. They are safe to people and wildlife, their specificity is very narrow. Their application as bioinsecticides was limited until recently because of their slow killing action and technical difficulties for in vitro commercial production. Two approaches for the wider application of baculoviruses as biopesticides will be implemented in future. In countries where use of genetically modified organisms is restricted, the improvements will be mainly at the level of diagnostics, in vitro production and changes in biopesticide formulations. In the second approach, the killing activity of baculoviruses may be augmented by genetic modifications of the baculovirus genome with genes of another natural pathogen. It is expected that the baculoviruses improved by genetic modifications will be gradually introduced in countries which have fewer concerns towards genetically modified organisms.

Animals↗

PubMed2005

Leptin regulates insulin sensitivity via phosphatidylinositol-3-OH kinase signaling in mediobasal hypothalamic neurons.

To investigate whether phosphatidylinositol-3 kinase (PI3K) signaling mediates the metabolic effects of hypothalamic leptin action, adenoviral gene therapy was used to direct expression of leptin receptors to the area of the hypothalamic arcuate nucleus (ARC). This intervention markedly improved insulin sensitivity in genetically obese, leptin-receptor-deficient Koletsky (fa(k)/fa(k)) rats via a mechanism that was not dependent on reduced food intake but was attenuated by approximately 44% by third-ventricular infusion of the PI3K inhibitor LY294002. Conversely, ARC-directed expression of a constitutively active mutant of protein kinase B (PKB/Akt, an enzyme activated by PI3K) mimicked the insulin-sensitizing effect of restored hypothalamic leptin signaling in these animals, despite having no effect on food intake or body weight. These findings suggest that hypothalamic leptin signaling is an important determinant of glucose metabolism and that the underlying neuronal mechanism involves PI3K.

Adenoviridae↗

PubMed2001

Influences of aging and caloric restriction on the transcriptional profile of skeletal muscle from rhesus monkeys.

In laboratory rodents, caloric restriction (CR) retards several age-dependent physiological and biochemical changes in skeletal muscle, including increased steady-state levels of oxidative damage to lipids, DNA, and proteins. We have previously used high-density oligonucleotide arrays to show that CR can prevent or delay most of the major age-related transcriptional alterations in the gastrocnemius muscle of C57BL/6 mice. Here we report the effects of aging and adult-onset CR on the gene expression profile of 7,070 genes in the vastus lateralis muscle from rhesus monkeys. Gene expression analysis of aged rhesus monkeys (mean age of 26 years) was compared with that of young animals (mean age of 8 years). Aging resulted in a selective up-regulation of transcripts involved in inflammation and oxidative stress, and a down-regulation of genes involved in mitochondrial electron transport and oxidative phosphorylation. Middle-aged monkeys (mean age of 20 years) subjected to CR since early adulthood (mean age of 11 years) were studied to determine the gene expression profile induced by CR. CR resulted in an up-regulation of cytoskeletal protein-encoding genes, and also a decrease in the expression of genes involved in mitochondrial bioenergetics. Surprisingly, we did not observe any evidence for an inhibitory effect of adult-onset CR on age-related changes in gene expression. These results indicate that the induction of an oxidative stress-induced transcriptional response may be a common feature of aging in skeletal muscle of rodents and primates, but the extent to which CR modifies these responses may be species-specific.

Aging↗

PubMed2003

Hypericum perforatum CO2 extract and opioid receptor antagonists act synergistically to reduce ethanol intake in alcohol-preferring rats.

BACKGROUND: Hypericum perforatum extracts attenuate ethanol intake in alcohol-preferring rats. The opioid receptor antagonists, naloxone and naltrexone, reduce ethanol intake in rats and humans. The combination of different agents that reduce ethanol intake has been proposed as an approach to the pharmacotherapy of alcoholism. This study evaluated the effect on ethanol intake of the combined administration of a CO2 H. perforatum extract and naloxone or naltrexone in genetically selected Marchigian Sardinian alcohol-preferring rats. METHODS: Ten percent (v/v) ethanol intake was offered 2 hr per day at the beginning of the dark phase of the reverse light-dark cycle. H. perforatum CO2 extract was given intragastrically, 1 hr before access to ethanol. Naloxone or naltrexone was given by intraperitoneal injection 10 min before the extract. RESULTS: H. perforatum CO2 extract reduced ethanol intake at 31 or 125 mg/kg, but not 7 mg/kg. These doses neither modified food or water intake during access to ethanol, nor reduce 0.2% saccharin intake. Naloxone reduced ethanol and food intake at 3 or 5 mg/kg, but not 1 mg/kg. When naloxone 1 mg/kg was combined with the three doses of H. perforatum CO2 extract, the attenuation of ethanol intake was more pronounced than that observed after the administration of the extract alone. Alcohol intake was also significantly reduced by 7 mg/kg of H. perforatum CO2 extract combined with naloxone 1 mg/kg. The combined treatments never modified the rat's locomotor activity nor the simultaneous intake of food, water or 0.2% saccharin. Naltrexone reduced ethanol intake at 1 and 3 mg/kg, but not at 0.5 mg/kg. When naltrexone 0.5 mg/kg was combined with H. perforatum CO2 extract 7 mg/kg, ethanol intake was markedly reduced. CONCLUSIONS: These findings provide evidence that H. perforatum CO2 extract and opiate receptor antagonists act synergistically to induce a pronounced and selective reduction of voluntary ethanol consumption in alcohol-preferring rats.

Alcohol Drinking↗

PubMed2005

The cost of resistance to Bacillus thuringiensis varies with the host plant of Trichoplusia ni.

Selection for resistance to insecticides, diseases and parasitoids is assumed to be costly and often requires tradeoffs with reproductive fitness. The costs of resistance, however, are often difficult to measure. Cabbage looper, Trichoplusia ni, a generalist Lepidopteran herbivore, has become highly resistant following the extensive use of the microbial insecticide, Bacillus thuringiensis kurstaki (Bt) in vegetable greenhouses. We compared the growth rate, pupal size and survival of resistant, susceptible and hybrid T. ni larvae fed on tomato, bell pepper and cucumber. Performance was best on cucumber and worst on pepper, and the magnitude of fitness costs associated with Bt resistance increased with declining host plant suitability. This supports the hypothesis that in this system, resistance costs are condition dependent and are greatest in the most stressful environment. Management strategies that rely on the presence of fitness costs to reduce the frequency of resistance genes must consider this variation and should be more successful on crops that are less suitable food plants. In general, condition dependence should be considered in studies designed to measure the costs of resistance.

Animals↗

PubMed2003

Enhanced food and water intake in renin transgenic rats.

In short term experiments angiotensin II (Ang II) is a potent stimulant of thirst, however it is not known whether prolonged activation of the renin-angiotensin system is associated with chronic alteration of water or food intake. Renin transgenic rats TGRmRen(2)27 (TGR) exhibit significant elevation of AngII in the brain regions involved in regulation of body fluid balance. The purpose of the present study was to find out whether TGR rats manifest also different water (WI) and food (FI) intake and renal excretory functions in comparison to their parent Sprague Dawley (SD) strain. To this end 24 h WI and FI as well as urine excretion (Vu) and urinary outputs of solutes (Cosm), sodium (UNaV) and potassium (UKV) were compared under baseline conditions in 16 TGR and 15 SD rats having free access to water and food. In 15 TGR and 17 SD rats effect of 24 h dehydration on water intake was investigated. Under baseline conditions TGR rats consumed significantly greater amount of food and water than SD rats. Vu, UNaV and UKV were not significantly different in both strains. Cumulative water intakes in SD and TGR rats subjected to 24 h dehydration did not differ. The results reveal that under baseline conditions TGR rats manifest greater food and water intakes than SD rats whereas stimulation of thirst by water deprivation is similar in both strains. The results suggest that the ingestive behavior may be chronically altered by upregulation of the renin-angiotensin system.

Animals↗

PubMed2005

Engineering of an oenological Saccharomyces cerevisiae strain with pectinolytic activity and its effect on wine.

A pectinolytic industrial yeast strain of Saccharomyces cerevisiae was generated containing the S. cerevisiae endopolygalacturonase gene (PGU1) constitutively expressed under the control of the 3-phosphoglycerate kinase gene (PGK1) promoter. The new strain contains DNA derived exclusively from yeast and expresses a high polygalacturonic acid hydrolyzing activity. Yeast transformation was carried out by an integrative process targeting a dispensable upstream region of the acetolactate synthase locus (ILV2), which determines sulfometuron methyl resistance. Microvinification assays were performed on white and red musts with the transformed UCLMS-1M strain and with the same strain untransformed. It was found that the changes in the pectic polysaccharide contents did not directly affect the taste or flavor of the wine. From the data reported, it is deduced that the chief advantage of using the modified strain is that it improves the yield of must/wine extraction, while it also positively affects some variables relating to appearance.

DNA, Fungal↗

PubMed2006

Biosecurity and the various types of embryos transferred.

The aim of the present paper was to review some features related to the risk analysis of three types of embryos to be transferred, namely the in vivo derived, the in vitro produced and the cloned ones. For in vivo-collected embryos, a considerable number of experiments and scientific investigations have been performed and hundreds of thousands of embryos are transferred annually with no contamination of associated diseases. Provided that the code of practice such as that published by the International Embryo Transfer Society is strictly followed by the embryo transfer practitioners, the statement made some 17 years ago saying that the in vivo-derived embryo transfer was the safest way of exchanging genes remains entirely true, thanks to the professionalism of the embryo transfer industry. For the in vitro-produced embryos, some particular rules have to be followed because of specific risks for some pathogens to strongly adhere to the zona pellucida of such embryos. There are some means to monitor and control those effects, and the transfer of in vitro-produced embryos can also be a very safe way to exchange genes around the world. The third type of embryos, the cloned ones, is a quite different category and the risk analysis to be soundly made still needs a lot of investigations so as to characterize the potential risks if there are, in terms not only of disease transmission but also in terms of public health, zoonotic risks as well as those related to quality and safety of food. The problem in this regard, is more directly addressed for offspring of clones than to the cloned embryos themselves. Published data on this issue are increasing in numbers so that progress in that area is expected in the few years to come.

Animals↗

PubMed1997

Expression of cholera toxin B subunit oligomers in transgenic potato plants.

A gene encoding the cholera toxin B subunit protein (CTB), fused to an endoplasmic reticulum (ER) retention signal (SEKDEL) was inserted adjacent to the bi-directional mannopine synthase P2 promoter in a plant expression vector containing a bacterial luciferase AB fusion gene (luxF) linked to the P1 promoter. Potato leaf explants were transformed by Agrobacterium tumefaciens carrying the vector and kanamycin-resistant plants were regenerated. The CTB-SEKDEL fusion gene was identified in the genomic DNA of bioluminescent plants by polymerase chain reaction amplification. Immunoblot analysis indicated that plant-derived CTB protein was antigenically indistinguishable from bacterial CTB protein, and that oligomeric CTB molecules (M(r) approximately 50 kDa) were the dominant molecular species isolated from transgenic potato leaf and tuber tissues. Similar to bacterial CTB, plant-synthesized CTB dissociated into monomers (M(r) approximately 15 kDa) during heat or acid treatment. The maximum amount of CTB protein detected in auxin-induced transgenic potato leaf and tuber tissues was approximately 0.3% of total soluble plant protein. Enzyme-linked immunosorbent assay methods indicated that plant-synthesized CTB protein bound specifically to GM1-ganglioside, the natural membrane receptor of cholera toxin. In the presence of the SEKDEL signal, CTB protein accumulates in potato tissues and is assembled into an oligomeric form that retains native biochemical and immunological properties. The expression of oligomeric CTB protein with immunological and biochemical properties identical to native CTB protein in edible plants opens the way for preparation of inexpensive food plant-based oral vaccines for protection against cholera and other pathogens in endemic areas throughout the world.

Agrobacterium tumefaciens↗

PubMed2001

Exercise, bone and nutrition.

Predisposition to poor skeletal health resulting in osteoporotic fracture is a major public health problem, the future economical impact of which is likely to be phenomenal. Two mechanisms principally determine adult bone health: (1) maximum attainment of peak bone mass (PBM); (2) the rate of bone loss with advancing age. Both aspects are regulated by a combination of endogenous and exogenous factors, and although genetic influences are believed to account for up to 75% of the variation in bone mass, there is still room for modifiable factors to play a vital role. Weight-bearing physical activity is beneficial to the skeleton, but clarification of the exact type, intensity and duration required for optimum bone mass is needed. Excessive levels of exercise, which result in amenorrhoea, are detrimental to skeletal health. The importance of Ca to bone remains controversial. There is evidence that Ca is effective in reducing late post-menopausal bone loss, but more research is required on the long-term benefit of increased Ca intake on PBM attainment. Vitamin D 'insufficiency' appears to be widespread amongst population groups and is an area of considerable public health concern. The role of other micronutrients on bone metabolism remains to be fully quantified, but data from a combination of experimental, clinical and observational studies suggest a positive link between alkaline-forming foods and indices of bone health. The influence of nutrient-gene interactions on the skeleton requires further elucidation, but it may be useful in the future to target nutrition advice at those individuals who are genetically susceptible to osteoporosis.

Aged↗

PubMed1993

Heritabilities of growth curve parameters and age-specific expression of genetic variation under two different feeding regimes in Japanese quail (Coturnix coturnix japonica).

This study investigated genetic variation in growth and final size in relationship to differences in heritabilities under good and poor feeding conditions. Heritabilities of growth and final size were estimated for several traits under ad libitum and restricted feeding conditions. A 30% feed restriction from hatching to 44 days of age in Japanese quail chicks decreased body weight and tarsus length at 44 days of age and the length of the third primary convert feather at 24 days of age relative to controls fed ad libitum. Wing length at 44 days of age was not significantly different for ad libitum fed and restricted quail. Genetic variances for body weight and tarsus length were very large throughout growth which resulted in heritability estimates close to one for these traits. The genetic correlations among feeding treatments were low, indicating that different genes were affecting growth under the two treatments. Growth was described by the components: asymptote, growth period, and shape of the growth curve following the modified Richards growth curve model (Brisbin et al. 1986). Tarsus length, which had high heritability of the parameter 'growth period' of the model, tended to display a higher heritability under the restriction than under ad libitum feeding. Body weight and feather length, which had either no heritable or low heritable 'growth periods' estimates, tended to be more heritable under ad libitum feeding. The shape parameter of the growth curve was not heritable for any trait, except tarsus length under restricted feeding.

Age Factors↗

PubMed1990

Characterization of transgenic livestock production.

The objective of transgenic livestock improvement projects is to develop and bring to market superior breeding stock, as well as germplasm for the artificial insemination and embryo transfer industries. Livestock animal biotechnology programs hold the promise of achieving, in a single generation, improvements in commercially important livestock species previously possible only through long-term traditional selective breeding practices or by chance mutation. Transgenic farm animals harboring growth hormone or metabolically related structural genes have been created. Studies of these animals demonstrate the effects of inadequate regulation of transgene expression. Research continues to explore the intricacies of developmental regulation of such genes and phenotypic consequences of mammalian gene transfer. Ultimately, genetically engineered livestock will provide producers with the benefit of increased production efficiencies while the consumer will have healthier animal food products. Conceivably, products will be produced with lower levels of fat, cholesterol, feed additives and pharmaceutical residues from animals with altered carcass composition that will result in greater nutritional benefit for the consumer.

Animals↗

PubMedDate not supplied

[Environmental factors in the etiopathology of inflammatory bowel syndrome].

Inflammatory bowel syndrome (IBS) mainly includes ulcerative colitis (UC) and Crohn's disease (CD). UC and CD are chronic and recurrent conditions, with a tendency to exacerbations and remissions. The incidence of diseases worldwide has increased over the last years. Although the etiology of inflammatory bowel syndrome has been studied intensively it still remains unclear. The development and persistence of inflammation is an effect of numerous factors: proinflammatory (aggressive), regulating bowel mucosa homeostasis and protective factors. Proinflammatory factors include intestinal bacteria, bile acids, digestive enzymes, lipopolysaccharides and peptidoglycans. Protective mechanisms are impermeability of mucosa barrier, presence of intestinal mucus, activity of secretive immunoglobulins, some prostaglandins and interleukins, glutamine, somatostatin, cortisol and short-chain fatty acids. Factors modifying intestinal mucosa homeostasis consist of genetically determined immunoregulators and activity of intestinal mucosa barrier and some environmental factors (diet, smoking, infections, stress, antibiotics and others). Environmental factors are jointly responsible for IBS occurrence in case of genetically determined dysregulation leading to proinflammatory cytokines overproduction or disturbances in synthesis of cytokines regulating intestinal mucosa homeostasis.

Colitis, Ulcerative↗

PubMed2004

Molecular and biologic characteristics of Toxoplasma gondii isolates from wildlife in the United States.

Toxoplasma gondii isolates can be grouped into 3 genetic lineages. Type I isolates are considered more virulent in outbred mice and have been isolated predominantly from clinical cases of human toxoplasmosis, whereas types II and III isolates are considered less virulent for mice and are found in humans and food animals. Little is known of genotypes of T. gondii isolates from wild animals. In the present report, genotypes of isolates of T. gondii from wildlife in the United States are described. Sera from wildlife were tested for antibodies to T. gondii with the modified agglutination test, and tissues from animals with titers of 1:25 (seropositive) were bioassayed in mice. Toxoplasma gondii was isolated from the hearts of 21 of 34 seropositive white-tailed deer (Odocoileus virginianus) from Mississippi and from 7 of 29 raccoons (Procyon lotor); 5 of 6 bobcats (Lynx rufus); and the gray fox (Urocyon cinereoargenteus), red fox (Vulpes vulpes), and coyote (Canis latrans) from Georgia. Toxoplasma gondii was also isolated from 7 of 10 seropositive black bears (Ursus americanus) from Pennsylvania by bioassay in cats. All 3 genotypes of T. gondii based on the SAG2 locus were circulating among wildlife.

Animals↗

PubMed2002

Increased production of nutriments by genetically engineered crops.

Plants are the basis of human nutrition and have been selected and improved to assure this purpose. Nowadays, new technologies such as genetic engineering and genomics approaches allow further improvement of plants. We describe here three examples for which these techniques have been employed. We introduced the first enzyme involved in fructan synthesis, the sucrose sucrose fructosyltransferase (isolated from Jerusalem artichoke), into sugar beet. The transgenic sugar beet showed a dramatic change in the nature of the accumulated sugar, 90% of the sucrose being converted into fructan. The use of transgenic sugar beet for the production and isolation of fructans will result in a more efficient plant production system of fructans and should promote their use in human food. The second example shows how the over-expression of the key enzyme of flavonoid biosynthesis could increase anti-oxidant levels in tomato. Introduction of a highly expressed chalcone isomerase led to a seventyfold increase of the amount of quercetin glucoside, which is a strong anti-oxidant in tomato. We were also able to modify the essential amino acid content of potato in order to increase its nutritional value. The introduction of a feedback insensitive bacterial gene involved in biosynthesis of aspartate family amino acids led to a sixfold increase of the lysine content. Because the use of a bacterial gene could appear to be controversial, we also introduced a mutated form of the plant key enzyme of lysine biosynthesis (dihydrodipicolinate synthase) in potato. This modification led to a 15 times increase of the lysine content of potato. This increase of the essential amino acid lysine influences the nutritional value of potato, which normally has low levels of several essential amino acids. These three examples show how the metabolism of primary constituents of the plant cell such as sugar or amino acids, but also of secondary metabolites such as flavonoids, can be modified by genetic engineering. Producing fructan, a soluble fiber, increasing the level of flavonoids, an antioxidant, in tomato or increasing the level of essential amino acids in potato are all clear examples of plant genetic modifications with possible positive effects on human nutrition.

Crops, Agricultural↗

PubMed2004

Bollgard II cotton: compositional analysis and feeding studies of cottonseed from insect-protected cotton (Gossypium hirsutum L.) producing the Cry1Ac and Cry2Ab2 proteins.

Bollgard II cotton event 15985 producing the Cry1Ac and Cry2Ab2 proteins has been developed by genetic modification to broaden the spectrum of insects to which the plant is tolerant and to provide an insect resistance management tool to impede the onset of resistance. The purpose of this study was to evaluate the composition and nutrition of Bollgard II cotton, relative to the use for food and animal feed, compared to that of conventional cotton varieties. Compositional analyses were conducted to measure proximate, fiber, amino acid, fatty acid, gossypol, and mineral contents of cottonseed from a total of 14 U.S. field sites over two years. Compositional analysis results showed that the cottonseed and cottonseed oil from Bollgard II cotton were comparable in their composition to those of the conventional control cotton line and other commercial varieties. The composition data are supported by nutritional safety studies conducted with dairy cows, catfish, and quail. Results from these studies showed that Bollgard II performed similarly to the conventional control cotton varieties. These data demonstrate that Bollgard II cotton is compositionally and nutritionally equivalent to conventional cotton varieties. These data support the conclusion that Bollgard II cotton is as safe and nutritious as conventional cotton for food and feed use.

Amino Acids↗

PubMed2005

Determination of flavonoids in cultivated sugarcane leaves, bagasse, juice and in transgenic sugarcane by liquid chromatography-UV detection.

A high-performance liquid chromatography (HPLC) method with photo-diode array (DAD) detection was developed to separate and quantify flavonoids in sugarcane leaves and bagasse (= the crushed sugarcane refuse from juice extraction), and in sugarcane juice. Sugarcane flavonoids consist of a complex mixture of aglycones and glycosides (including flavonolignan glycosides), and the HPLC-UV method herein proposed is suitable for their quantification as total flavonoids. This method was applied to analyze samples of cultivated sugarcane, commercial juice and transgenic sugarcane leaves. Sugarcane leaves proved a promising source of flavonoids: an average of 1.10 mg of total flavonoids/g plant material was found in fresh leaves. Moreover, the flavonoid content of sugarcane juice (0.6 mg/mL) is comparable to other food sources of flavonoids previously reported. Transgenic sugarcane leaves ("Bowman-Birk" and "Kunitz") were compared with non-modified ("control") plant samples using the proposed HPLC-UV method, which indicated that the content of total flavonoids in transgenic plants is different from that in non-modified sugarcane.

Cellulose↗