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PubMed2001

Enhanced levels of the aroma and flavor compound S-linalool by metabolic engineering of the terpenoid pathway in tomato fruits.

The aromas of fruits, vegetables, and flowers are mixtures of volatile metabolites, often present in parts per billion levels or less. We show here that tomato (Lycopersicon esculentum Mill.) plants transgenic for a heterologous Clarkia breweri S-linalool synthase (LIS) gene, under the control of the tomato late-ripening-specific E8 promoter, synthesize and accumulate S-linalool and 8-hydroxylinalool in ripening fruits. Apart from the difference in volatiles, no other phenotypic alterations were noted, including the levels of other terpenoids such as gamma- and alpha-tocopherols, lycopene, beta-carotene, and lutein. Our studies indicate that it is possible to enhance the levels of monoterpenes in ripening fruits by metabolic engineering.

Acyclic Monoterpenes↗
PubMed1988

Obesity, genetics, and ponderal set point.

A significant proportion of the interindividual variance in human fatness is attributable to genetic factors. This fact is indicated (inter alia) by studies of identical twins demonstrating that the degree of efficiency with which the body uses excess dietary energy for fat storage is, to a considerable extent, inherited. Genetic factors also appear to render particular individuals or groups especially vulnerable to pervasive obesity-promoting influences (excess food and too little exercise) in the environment. If, indeed, much human obesity results from an interaction between a genetically determined disposition to store fat efficiently and a food-laden, overmechanized environment, then preventive and therapeutic strategies should be directed toward (a) helping the susceptible individual protect himself from the "calorie pollution" that surrounds him, and (b) finding pharmacologic agents to modify the inherited metabolic factors that favor excessive fat storage.

Energy Metabolism↗
PubMed2003

Expression of mercuric ion reductase in Eastern cottonwood (Populus deltoides) confers mercuric ion reduction and resistance.

Mercury is one of the most hazardous heavy metals and is a particular problem in aquatic ecosystems, where organic mercury is biomagnified in the food chain. Previous studies demonstrated that transgenic model plants expressing a modified mercuric ion reductase gene from bacteria could detoxify mercury by converting the more toxic and reductive ionic form [Hg(II)] to less toxic elemental mercury [Hg(0)]. To further investigate if a genetic engineering approach for mercury phytoremediation can be effective in trees with a greater potential in riparian ecosystems, we generated transgenic Eastern cottonwood (Populus deltoides) trees expressing modified merA9 and merA18 genes. Leaf sections from transgenic plantlets produced adventitious shoots in the presence of 50 microm Hg(II) supplied as HgCl2, which inhibited shoot induction from leaf explants of wild-type plantlets. Transgenic shoots cultured in a medium containing 25 microm Hg(II) showed normal growth and rooted, while wild-type shoots were killed. When the transgenic cottonwood plantlets were exposed to Hg(II), they evolved 2-4-fold the amount of Hg(0) relative to wild-type plantlets. Transgenic merA9 and merA18 plants accumulated significantly higher biomass than control plants on a Georgia Piedmont soil contaminated with 40 p.p.m. Hg(II). Our results indicate that Eastern cottonwood plants expressing the bacterial mercuric ion reductase gene have potential as candidates for in situ remediation of mercury-contaminated soils or wastewater.

Journal Article↗
PubMed2000

Is there a future for GMOs?

Despite strict regulation and a clean safety record, research and development of genetically modified (GM) crops and other organisms has been confronted with tremendous public hostility. Why has this happened, and how can scientists try to guide the debate into more rational channels? The answers may determine the future of GM technology and our ability to provide for a growing world population.

Biotechnology↗
PubMed2003

Nutritional enhancement of plants.

Plants can provide most of the nutrients required in the human diet; however, the major staple crops are often deficient in some of these nutrients. Thus, malnutrition, with respect to micronutrients like vitamin A, iron and zinc, affects >40% of the world's population. Advances in molecular biology are being exploited to produce crops enhanced in these key nutrients. Other nutritional targets include the modification of fatty acid composition and the enhancement of antioxidant levels, particularly carotenoids, such as lycopene, and flavonoids. However, the benefit of these 'biofortified' crops to human nutrition remains to be elucidated.

Agriculture↗
PubMed1995

The pathogenesis and diagnosis of canine hip dysplasia: a review.

Hip dysplasia is a common developmental problem affecting the canine population. Despite extensive research into the condition, many questions remain unanswered and numerous misconceptions are present among the general public. The purpose of this paper is to review the current knowledge on the development of hip dysplasia, factors modifying its development, and current diagnostic techniques.A computerized literature search was conducted for the period of January 1983 to April 1985 using the MEDLINE and CAB databases, and the keywords hip dysplasia, hip, dog, and canine. Other articles,wherever possible original research articles, published before 1983 were also reviewed. Animals affected by hip dysplasia are born with normal hips, but quickly develop subluxation of the femoral head. Degenerative joint disease follows. Hip dysplasia is a complex, inherited, polygenic trait. Selective breeding of only normal dogs with normal littermates, parents, and grandparents is there commended method of reducing the incidence in the general population.Gene expression in affected individuals may be modified by a number of environmental factors. These factors do not cause hip dysplasia, but they alter manifestations of the trait and its severity. Nutrition is a major environmental factor. Excess energy consumption increases the frequency and severity of hip dysplasia in genetically predisposed dogs. Food intake should be regulated to maintain a slender figure with the ribs and dorsal vertebral spines easily palpable, but not visible. Excess dietary calcium and vitamin D contribute to hip dysplasia in genetically predisposed individuals and should be avoided. High dose vitamin C supplementation ingrowing puppies does not prevent hip dysplasia, and this practice should be discontinued. Animals must be 2 years old before they can be certified as normal, but the disease may be diagnosed earlier. Earlier diagnosis of the condition would be very useful for the selection of breeding stock, but palpation techniques and the standard extended view radiographs have unacceptably high rates of error in young puppies. Stress radiography techniques may improve the accuracy of early diagnosis in the future.

Animals↗
PubMed1994

Accumulation of fructose polymers in transgenic tobacco.

Fructan, a polyfructose molecule, is a storage compound in a limited number of plant species. Usually these species accumulate fructan with a low degree of polymerization (DP) and most of these plants have properties which preclude their use as a fructan source. With the eventual aim of allowing the accumulation of high DP fructans in non-fructan storing plants, we have investigated whether carbohydrate flow in the plant cell can be directed to produce this polymer. For this purpose the SacB gene from Bacillus subtilis, which encodes levansucrase, was modified and introduced into tobacco plants. Transgenic plants containing the sacB gene accumulate fructans. The size and properties of this fructan are similar to fructan produced by Bacillus subtilis, and is stable in plants. Although the level of fructan accumulation in the transgenic tobacco plants ranged from 3-8 percent of the dry weight, no levansucrase mRNA or protein could be detected in these plants. Extension of this work should permit the production of this high molecular weight biopolymer in crop plants for applications in food and non-food products.

Bacillus subtilis↗
PubMed2004

Metabolic adaptations of three inbred strains of mice (C57BL/6, DBA/2, and 129T2) in response to a high-fat diet.

Although it is now becoming more evident that the strain of mouse used to generate genetically modified models for the study of endocrine disorders contributes to the ensuing phenotype, metabolic characterization of these common strains used to produce genetically altered mice has been limited. The aim of this study therefore was to measure various metabolic parameters in C57BL/6, DBA/2, and 129T2 mice fed a control or a high-fat diet. Mice were fed either a control (7 g/100 g) or a high-fat (60 g/100 g) diet for 6 wk. During wk 6, spontaneous and voluntary physical activity and resting energy expenditure were determined. DBA/2 mice that consumed the control diet gained more weight and had larger regional fat pad depots than either C57BL/6 or 129T2 mice (P < 0.05). Spontaneous and voluntary activity was lower in 129T2 mice compared with DBA/2 or C57BL/6 mice (P < 0.05). Resting energy expenditure (corrected for body weight) was greater in C57BL/6 mice than in DBA/2 or 129T2 mice (P < 0.05), whereas glucose and fat oxidation did not differ among the 3 strains of mice. Plasma glucose concentrations in food-deprived mice were higher and insulin concentrations lower in 129T2 compared with C57BL/6 mice (P < 0.05), but were not affected by the high-fat diet in any of the 3 strains tested. This study shows that these 3 commonly used inbred strains of mice have different inherent metabolic characteristics. It further highlights that the background strain used to produce genetically modified mice is critical to the resultant phenotype.

Adaptation, Physiological↗
PubMed2004

Growth enhancement and food conversion efficiency of transgenic fish Labeo rohita.

Three family lines of fast growing transgenic rohu Labeo rohita (rohu) were generated by electroporated-sperm-mediated transfer of the vectors harboring CMV promoter or grass carp beta-actin promoter fused to endogenous rohu GH (rGH) cDNA. The gene transfer efficiency was 25%. The transgenic rohu (family line 1) with CMV promoter showed a growth enhancement of four times normal size, whereas those (family lines 2 and 3) generated with beta-actin promoter grew 4.5 and 5.8 times faster than their respective control siblings. Southern analysis confirmed the transgene extrachromosomal (Te) persistence until the 60th week in family 1. The individuals of family lines 2 and 3, however, showed integration (Ti), as well as persistence as extrachromosomal copies (Te) until the age of 30 weeks. Mosaicism of the transgene was shown at the levels of its presence and expression. The ectopic expression of rGH mRNA was confirmed by RT-PCR. Feeding experiments revealed that the transgenic rohu ate food at a lower rate but grew more efficiently than their control siblings.

Actins↗
PubMedDate not supplied

Effects of Hypericum perforatum extraction on alcohol intake in Marchigian Sardinian alcohol-preferring rats.

The present study investigated the effect of acute intragastric (i.g.) administration of dry Hypericum perforatum extract (HPE), containing 0.3% hypericin, on ethanol intake in genetically selected Marchigian Sardinian alcohol-preferring (msP) rats. The i.g. administration of HPE, 125 or 250 mg/kg, induced a 30-40% reduction in ethanol intake in rats offered 10% (v/v) ethanol for 2 h/day. The effect of these doses was selective, since they modified neither food intake nor food-associated drinking; neither did the same doses modify the rat's gross behaviour in the open-field test. A dose of 500 mg/kg frequently induced immobility and a general suppression of ingestive behaviour. In rats offered 10% ethanol for 12 h/day, ethanol intake following treatment with 250 mg/kg HPE was significantly lower than that of controls for up to 10 h. The effect on ethanol intake was not related to the antidepressant-like effect of HPE revealed in the forced swimming test. In this regard, the effect on ethanol intake was observed after a single administration of 125 mg/kg, whereas the antidepressant effect was observed only after repeated treatment with doses higher than 125 mg/kg HPE. The i.g. administration of HPE, 250 mg/kg, did not affect blood-alcohol levels following i.g. treatment with 0.7 g/kg ethanol, the amount usually ingested in a single drinking episode; thus, the effect is not related to changes in the pharmacokinetics of ethanol. The present study shows that HPE markedly reduces ethanol intake in msP rats, without significantly modifying food intake.

Alcohol Deterrents↗
PubMed1975

Diet and atherosclerosis.

Diet and atherosclerosis are closely linked, both aetiologically and therapeutically. The aetiological association can be demonstrated most satisfactorily in animal experiments. In human beings the evidence must necessarily be more indirect and is largely based on dietary trials and epidemiological surveys linking the intake of cholesterol and saturated fat with morbidity and mortality from coronary disease. A modifying influence which has gained increasing recognition over recent years is the individual response to a given diet. This variability appears to be largely genetically determined, certainly in the defined primary hyperlipidaemic states, and possibly within the normal ranges of serum cholesterol levels. A change in food habits should be fully utilized therapeutically in any form of hyperlipidaemia, whether as a primary preventive measure before clinical diseases of atherosclerotic origin become manifest or in secondary prevention to delay further morbidity and mortality. With good dietary adherence, lipid levels may return to normal and there may be additional favourable effects on intravascular thrombosis. Many problems remain to be solved on the public health issue of advising changes in the national diet. A number of countries in which an atherogenic diet is habitually eaten have decided in favour of such a recommendation. Public education, identification of persons at risk and provision of readily available skilled medical and dietary counselling should constitute a national health project with rewarding long-term results.

Adult↗
PubMed2006

Novel soybean oils with different fatty acid profiles alter cardiovascular disease risk factors in moderately hyperlipidemic subjects.

BACKGROUND: A variety of soybean oils were developed with improved oxidative stability and functional characteristics for use as alternatives to partially hydrogenated fat. OBJECTIVE: The objective was to assess the effect of selectively bred and genetically modified soybean oils with altered fatty acid profiles, relative to common soybean and partially hydrogenated soybean oils, on cardiovascular disease risk factors. DESIGN: Thirty subjects (16 women and 14 men) aged >50 y with LDL-cholesterol concentrations >130 mg/dL at screening consumed 5 experimental diets in random order for 35 d each. Diets contained the same foods and provided 30% of energy as fat, of which two-thirds was either soybean oil (SO), low-saturated fatty acid soybean oil (LoSFA-SO), high-oleic acid soybean oil (HiOleic-SO), low-alpha-linolenic acid soybean oil (LoALA-SO), or partially hydrogenated soybean oil (Hydrog-SO). RESULTS: Plasma phospholipid patterns reflected the predominant fat in the diet. LDL-cholesterol concentrations were 3.66 +/- 0.67(b), 3.53 +/- 0.77(b), 3.70 +/- 0.66(b), 3.71 +/- 0.64(a,b), and 3.92 +/- 0.70(a) mol/L; HDL-cholesterol concentrations were 1.32 +/- 0.32(a,b), 1.32 +/- 0.35(b), 1.36 +/- 0.33(a), 1.32 +/- 0.33(b), and 1.32 +/- 0.32(a,b) mol/L for the SO, LoSFA-SO, HiOleic-SO, LoALA-SO, and Hydrog-SO diets, respectively (values with different superscript letters are significantly different, P < 0.05). No significant effects were observed on VLDL-cholesterol, triacylglycerol, lipoprotein(a), and C-reactive protein concentrations or on ratios of LDL cholesterol to apolipoprotein B (apo B) and HDL cholesterol to apo A-I. Total cholesterol:HDL cholesterol was lower after subjects consumed the unhydrogenated soybean oils than after they consumed the Hydrog-SO diet. CONCLUSIONS: All varieties of soybean oils resulted in more favorable lipoprotein profiles than did the partially hydrogenated form. These soybean oils may provide a viable option for reformulation of products to reduce the content of trans fatty acids.

Apolipoproteins↗
PubMed2006

Expression of masu salmon delta5-desaturase-like gene elevated EPA and DHA biosynthesis in zebrafish.

Farmed fish could substitute for marine capture fish as a source of fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) beneficial for human health; however, they require these compounds in their diets. In the present study on a model fish species, we modified the EPA/DHA biosynthesis pathway by overexpression of masu salmon Delta5-desaturase-like gene in zebrafish to increase its ability to synthesize EPA and DHA. Expression of this gene in transgenic fish fed a commercial diet and Artemia helped to improve their EPA content by 1.21-fold and DHA by 1.24-fold. In similar fish that were fed only Artemia the increments were 1.14-fold for EPA and 1.13-fold for DHA, compared with nontransgenic fish. In contrast, eicosatetraenoic acid content decreased, as it is a substrate of Delta5-desaturase, while the total lipid remained constant. The results demonstrated that masu salmon Delta5-desaturase is functional in zebrafish and can modify its fatty acid metabolic pathway. The technique could be applied to farmed fish to generate a nutritionally richer product for human consumption.

Actins↗
PubMed2004

Enzymes for transgenic biosynthesis of long-chain polyunsaturated fatty acids.

Polyunsaturated fatty acids (PUFAs) are important for the normal development and function of all organisms, and are essential in maintaining human health. Impaired PUFA metabolism is thought to be associated with pathogenesis of many chronic diseases. Dietary supplementation of PUFAs, such as gamma-linolenic acid, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid, which bypass the defective or dysfunctional steps of the biosynthetic pathway has been found to significantly alleviate the symptoms of the disease. These findings have drawn a great deal of interest from general public and food manufacturers. As the demand of these beneficial PUFAs has drastically increased in recent years, there are also increasing efforts in finding the alternate sources of PUFAs that are more economical and sustainable. One option is to modify the oil-seed crops to produce PUFAs through genetic engineering technique. This review examines the isolation, identification and expression of genes encoding the enzymes required for the biosynthesis of the above mentioned PUFAs in plants.

Acetyltransferases↗
PubMed2006

Control of energy homeostasis: role of enzymes and intermediates of fatty acid metabolism in the central nervous system.

The regulation of energy homeostasis is critical for normal physiology and survival. Energy flux must be rigorously monitored and adjusted to ensure that fuel intake and expenditure remain within acceptable limits. The central nervous system (CNS) is, in large part, responsible for conducting this energy-monitoring function and for integrating the numerous inputs. It has become evident that neurons of the CNS monitor and respond to levels of metabolic intermediates that reflect peripheral energy status. Intermediates in the fatty acid biosynthetic pathway have been implicated as hypothalamic signaling mediators that sense and respond to changes in circulating fuels. Genetic and pharmacologic manipulation of the enzymes of fatty acid metabolism have led to the hypothesis that neuronal metabolic intermediates affect neural outputs that modify both feeding behavior and energy expenditure. This review focuses on the regulatory roles of these enzymes and intermediates in the regulation of food intake and energy balance.

Central Nervous System↗
PubMed2003

A novel approach to the use of genetically modified herbicide tolerant crops for environmental benefit.

The proposed introduction of genetically modified herbicide tolerant (GMHT) crops, with claims of improved weed control, has prompted fears about possible environmental impacts of their widespread adoption, particularly on arable weeds, insects and associated farmland birds. In response to this, we have developed a novel weed-management system for GMHT sugar beet, based on band spraying, which exploits the flexibility offered by the broad-spectrum partner herbicides. Here, we show the results from two series of field experiments which, taken together, demonstrate that, by using this system, crops can be managed for enhanced weed and insect biomass without compromising yield, thus potentially offering food and shelter to farmland birds and other wildlife. These results could be applicable widely to other row crops, and indicate that creative use of GMHT technology could be a powerful tool for developing more sustainable farming systems in the future.

Animals↗