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The potential for biotechnology to improve the nutritional value of cassava.

Cassava, a starch-rich plant that has poor protein content and usually poor vitamin content, feeds about 600 million people each day. When cereals can no longer be grown because of soil fertility problems, it is often still possible to grow cassava. It is the third most important source of dietary calories in the tropics, and reliance on the crop is especially high in West and Central Africa. The International Laboratory for Tropical Agricultural Biotechnology is promoting research to improve cassava productivity and is a leader in developing genetic engineering to improve the quantitative and qualitative traits of this essential food crop.

Developing Countries↗

Carotenoid-rich bananas: a potential food source for alleviating vitamin A deficiency.

This review article points out that bananas are an important food for many people in the world. Thus, banana cultivars rich in provitamin A carotenoids may offer a potential food source for alleviating vitamin A deficiency, particularly in developing countries. Many factors are associated with the presently known food sources of vitamin A that limit their effectiveness in improving vitamin A status. Acceptable carotenoid-rich banana cultivars have been identified in Micronesia, and some carotenoid-rich bananas have been identified elsewhere. Bananas are an ideal food for young children and families for many regions of the world, because of their sweetness, texture, portion size, familiarity, availability, convenience, versatility, and cost. Foods containing high levels of carotenoids have been shown to protect against chronic disease, including certain cancers, cardiovascular disease, and diabetes. Because the coloration of the edible flesh of the banana appears to be a good indicator of likely carotenoid content, it may be possible to develop a simple method for selecting carotenoid-rich banana cultivars in the community. Research is needed on the identification of carotenoid-rich cultivars, targeting those areas of the world where bananas are a major staple food; investigating factors affecting production, consumption, and acceptability; and determining the impact that carotenoid-rich bananas may have on improving vitamin A status. Based on these results, interventions should be undertaken for initiating or increasing homestead and commercial production.

Animal Feed↗

Immunogenic and allergenic potentials of natural and recombinant innocuous proteins.

A new aspect of protein immunogenic and allergenic properties has become important recently, when there is a higher chance that our immune system will be exposed to novel protein antigens and/or familiar protein antigens with an unprecedented high frequency and large amount. These proteins are innocuous, nontoxic, and noninvasive by themselves, and include various natural proteins from the environment and recombinant proteins from industry. The technical term allergenic has been used for such proteins and their abilities to induce specific IgE production and to cross-link IgE/Fc epsilonRI on the surface of mast cells and basophiles have been recognized. As for the environmental proteins, some physicochemical properties (solubility, stability, and permeability across a mucosal epithelium) of the proteins indirectly play important roles in their allergenic potential because they do not originate from invasive pathogens as vehicles. Indeed, several lines of experimental evidences have been accumulated indicating that all proteins are absorbed across mucosal epithelia by transcellular transport and/or through interstitial spaces among the epithelial cells but not at equal levels. Some animal models have been established for natural sensitization to some allergenic proteins by feeding or intragastric administration without an adjuvant and, in a few cases, some symptoms resembling human allergy and even anaphylaxis have been induced by oral challenge with the proteins. Sometimes, even to self-proteins, the immunogenic or allergenic potential is given by post-translational modifications and possibly by unknown structural/conformational alterations, when they are exogenous self-proteins, such as recombinant human proteins for drug use. Despite the accumulation of knowledge and the progress in analytical technology on protein allergenicity, it is still crucial to predict the allergenic potential of novel and unused proteins. However, some animal models are applicable for assessing the relative allergenic potential of processed proteins in comparison with that of native proteins in preclinical studies.

Absorption↗

Genetically engineered crops: their potential use for improvement of human nutrition.

Great success has been achieved in increasing agriculture productivity to fulfill human needs during the second half of the 20th century. However, there will be much greater challenges in the future. Based on the current population growth rate of 1.4% per year, the world's population is forecast to increase from the current level of approximately six billion to nine to twelve billion in 50 years. In addition to continuously increasing demand for agricultural production, there is an urgent need to improve the nutritional quality of human diets for this rapidly growing human population. Malnutrition is still a worldwide health issue. Macronutrient and micronutrient deficiencies are prevalent in developing countries, and over-consumption of certain nutrients in developed countries (e.g., saturated fatty acids) is associated with high incidence of certain chronic diseases. Furthermore, there will be declining natural resources such as arable land and water, and the challenges to humans must be met without further degrading the environment. Biotechnology offers a valuable tool to help achieve these goals. This review focuses on the most recent advances in biotechnology, which promise to improve human nutrition by enhancing the nutrient density of plant foods. Issues relating to the safety of food products from genetically engineered crops are also discussed.

Agriculture↗

Fit for a king.

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Food Technology↗

Power corrupts.

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Agriculture↗

Sources of uncertainty in the quantification of genetically modified oilseed rape contamination in seed lots.

Testing of seed and grain lots is essential in the enforcement of GM labelling legislation and needs reliable procedures for which associated errors have been identified and minimised. In this paper we consider the testing of oilseed rape seed lots obtained from the harvest of a non-GM crop known to be contaminated by volunteer plants from a GM herbicide tolerant variety. The objective was to identify and quantify the error associated with the testing of these lots from the initial sampling to completion of the real-time PCR assay with which the level of GM contamination was quantified. The results showed that, under the controlled conditions of a single laboratory, the error associated with the real-time PCR assay to be negligible in comparison with sampling error, which was exacerbated by heterogeneity in the distribution of GM seeds, most notably at a small scale, i.e. 25 cm3. Sampling error was reduced by one to two thirds on the application of appropriate homogenisation procedures.

Base Sequence↗

Food-anticipatory activity and liver per1-luc activity in diabetic transgenic rats.

The mammalian Per1 gene is an important component of the core cellular clock mechanism responsible for circadian rhythms. The rodent liver and other tissues rhythmically express Per1 in vitro but typically damp out within a few cycles. In the liver, the peak of this rhythm occurs in the late subjective night in an ad lib-fed rat, but will show a large phase advance in response to restricted availability of food during the day. The relationship between this shift in the liver clock and food-anticipatory activity (FAA), the circadian behavior entrained by daily feeding, is currently unknown. Insulin is released during feeding in mammals and could serve as an entraining signal to the liver. To test the role of insulin in the shift in liver Per1 expression and the generation of FAA, per-luciferase transgenic rats were made diabetic with a single injection of streptozotocine. Following 1 week of restricted feeding and locomotor activity monitoring, liver was collected for per-luc recording. In two separate experiments, FAA emerged and liver Per1 phase-shifted in response to daytime 8-h food restriction. The results rule out insulin as a necessary component of this system.

Animals↗

Evaluation of the potential allergenicity of the enzyme microbial transglutaminase using the 2001 FAO/WHO Decision Tree.

All novel proteins must be assessed for their potential allergenicity before they are introduced into the food market. One method to achieve this is the 2001 FAO/WHO Decision Tree recommended for evaluation of proteins from genetically modified organisms (GMOs). It was the aim of this study to investigate the allergenicity of microbial transglutaminase (m-TG) from Streptoverticillium mobaraense. Amino acid sequence similarity to known allergens, pepsin resistance, and detection of protein binding to specific serum immunoglobulin E (IgE) (RAST) have been evaluated as recommended by the decision tree. Allergenicity in the source material was thought unlikely, since no IgE-mediated allergy to any bacteria has been reported. m-TG is fully degraded after 5 min of pepsin treatment. A database search showed that the enzyme has no homology with known allergens, down to a match of six contiguous amino acids, which meets the requirements of the decision tree. However, there is a match at the five contiguous amino acid level to the major codfish allergen Gad c1. The potential cross reactivity between m-TG and Gad c1 was investigated in RAST using sera from 25 documented cod-allergic patients and an extract of raw codfish. No binding between patient IgE and m-TG was observed. It can be concluded that no safety concerns with regard to the allergenic potential of m-TG were identified.

Animals↗

Gene discovery and product development for grain quality traits.

The composition of oils, proteins, and carbohydrates in seeds of corn, soybean, and other crops has been modified to produce grains with enhanced value. Both plant breeding and molecular technologies have been used to produce plants carrying the desired traits. Genomics-based strategies for gene discovery, coupled with high-throughput transformation processes and miniaturized, automated analytical and functionality assays, have accelerated the identification of product candidates. Molecular marker-based breeding strategies have been used to accelerate the process of moving trait genes into high-yielding germplasm for commercialization. These products are being tested for applications in food, feed, and industrial markets.

Biotechnology↗

Proteomics as a tool to improve investigation of substantial equivalence in genetically modified organisms: the case of a virus-resistant tomato.

At present, the so-called "substantial equivalence" is the only widely accepted criterion for deciding whether or not a transgenic food is, from an alimentary point of view, to be considered totally correspondent to the "traditional" one from which it derives. Although never exactly defined, it deals with a comparison between the chemical composition of the two foods. A more in-depth analysis can be performed by one of the most suitable methods that allows for the simultaneous screening of many components without prior identification, the analysis of the proteome. As a model for testing this kind of approach, we compared protein expression of two types of tomato plants, having the same genetic background, except for a virus resistance trait introduced by genetic engineering. When proteins extracted from seedlings of the two types were analyzed by two-dimensional electrophoresis, no significant differences, either qualitative or quantitative, were detected, indicating that in this case the expression of major proteins was unmodified by the genetic manipulation. Fifteen proteins were identified by peptide mass fingerprinting.

Solanum lycopersicum↗

Allergy assessment of foods or ingredients derived from biotechnology, gene-modified organisms, or novel foods.

The introduction of novel proteins into foods carries a risk of eliciting allergic reactions in individuals sensitive to the introduced protein and a risk of sensitizing susceptible individuals. No single predictive test exists to perform a hazard assessment in relation to allergenic properties of newly expressed proteins in gene-modified organisms (GMOs). Instead, performance of a weighted risk analysis based on the decision tree approach has been suggested. The individual steps of this analysis comprise sequence homology to known allergens, specific or targeted serum screens for immunoglobulin E (IgE) cross-reactions to known allergens, digestability studies of the proteins in simulated gastric and/or intestinal fluids, and animal studies. These steps are discussed and five examples of risk evaluation of GMOs or novel foods are presented. These include ice-structuring protein derived from fish, microbial transglutaminase, GMO-soybeans, amylase and the Nangai nut.

Allergens↗

Effects of pair-feeding and growth hormone treatment on obese transgenic rats.

BACKGROUND: It has been shown that GH-deficient subjects tend to have fat accumulation. We have produced human GH (hGH) transgenic rats that exhibit low circulating hGH levels and hyperphagia. These rats are also characterized by severe obesity, hyperinsulinemia and hyperlipidemia. OBJECTIVE: The present study was conducted in order to elucidate how excess caloric intake and impaired GH secretion account for fat accumulation and metabolic abnormalities in the transgenic rats. DESIGN AND METHODS: The transgenic rats were subjected to either pair-feeding with non-transgenic controls or hGH treatment from 4 to 12 weeks of age, and the effects on fat accumulation and some metabolic parameters were assessed. RESULTS: At the age of 12 weeks, body weight and food intake were greater in transgenic than in control rats by 10% and 27% respectively. The ratio of epididymal white adipose tissue weight to body weight (WAT/BW) was more than three times greater in transgenic than in control rats. Although pair-feeding for 8 weeks decreased body weight, it did not affect the WAT/BW ratio. Treatment with hGH affected neither body weight nor food intake, while it reduced the WAT/BW ratio by 30%. Serum concentrations of triglyceride, free fatty acid, insulin and leptin were all significantly higher in the transgenic than in the control rats. Pair-feeding decreased serum triglyceride, insulin and leptin levels, but not serum free fatty acid levels. On the other hand, hGH treatment decreased only serum leptin concentrations. CONCLUSIONS: These results suggest that severe fat accumulation in the transgenic rats mainly resulted from the decreased lipolytic action of GH, while metabolic abnormalities mainly resulted from excess caloric intake.

Adipose Tissue↗

Mass spectrometric detection of CP4 EPSPS in genetically modified soya and maize.

The potential of protein fractionation hyphenated to mass spectrometry (MS) to detect and characterize the transgenic protein present in Roundup Ready soya and maize has been investigated. Genetically modified (GM) soya and maize contain the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene from Agrobacterium tumefaciens CP4, which confers resistance to the herbicide glyphosate. The GM soya and maize proteomes were fractionated by gel filtration, anion-exchange chromatography and sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) prior to MS. This facilitated detection of a tryptic peptide map of CP4 EPSPS by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS and nanoelectrospray ionization quadrupole time-of-flight (nanoESI-QTOF) MS. Subsequently, sequence information from the CP4 EPSPS tryptic peptides was obtained by nanoESI-QTOF MS/MS. The identification was accomplished in 0.9% GM soya seeds, which is the current EU threshold for food-labeling requirements.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗

Digestibility of allergens extracted from natural rubber latex and vegetable foods.

BACKGROUND: Several cross-reactive allergens are now known to be involved in the defense responses of higher plants. Such proteins are drawing the attention of plant breeders because of their antimicrobial or stress-alleviating activities. Plants genetically modified to express defense-related proteins are being developed. The current concern is focused on the allergenicity of these intentionally expressed proteins. OBJECTIVE: It is believed that food allergens are proteins resistant to digestion. Digestibility tests have been accepted as an appropriate method for evaluating the allergenicity of newly introduced proteins. In this study we investigated the usefulness of this method for detecting allergens from natural rubber latex and vegetable foods. METHODS: Proteins were extracted from rubber latex, potato, and 5 kinds of fruits. Simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were used for the digestibility test. An aliquot of each digest was periodically withdrawn and analyzed. Allergens were detected with pooled sera from individuals with latex allergy or patients given a diagnosis of oral allergy syndrome. RESULTS: Most latex and vegetable food proteins were digested by the SGF within 4 minutes. Numerous allergens were also decomposed by the SGF within 8 minutes. Although vegetable food allergens were relatively stable in the SIF, kiwi allergens were substantially degraded by the SIF within 16 hours. CONCLUSION: The pronounced lability of the plant-derived allergens was thought to reflect the discrete sensitization and elicitation processes of patients with latex-fruit syndrome or oral allergy syndrome. These results indicate that the allergenicity of a newly expressed protein should be carefully evaluated according to not only its digestibility but also other important properties.

Allergens↗

Blockade of pre- and post-synaptic 5-HT1A receptors does not modify the effect of fluoxetine or 5-hydroxytryptophan on ethanol and food intake in rats.

Selective serotonin reuptake inhibitors (SSRIs) or serotonin precursors inhibit ethanol and food intake by increasing the synaptic availability of 5-HT in the central nervous system. However, these agents can also increase 5-HT levels at somatodendritic 5-HT1A autoreceptors, with negative effects on serotonergic transmission. (+)WAY100135 [N-ter-butyl 3-4-(2-methoxy-phenyl) piperazin-1-yl-2-phenylpropanamide dihydrochloride] is a selective antagonist both at pre- and post-synaptic 5-HT1A receptors. The present study investigated the effect on ethanol and food intake of (+)WAY100135, given alone or coadministered with the SSRI fluoxetine or the 5-HT precursor 5-hydroxytryptophan (5-HTP) in genetically selected alcohol-preferring rats. Blockade of presynaptic 5-HT1A receptors after injection of (+)WAY100135, 0.1 or 1 microgram/rat, into the dorsal raphe did not significantly modify ethanol, food or total fluid intake. The same doses of (+)WAY100135 did not modify the inhibition of ethanol and food intake induced by intraperitoneal (i.p.) injection of fluoxetine, 5 mg/kg. Subcutaneous (s.c.) administration of (+)WAY100135 (1 or 10 mg/kg) did not affect the 3-h, or the overnight intake of ethanol, food or total fluids. Given together with i.p. fluoxetine (5 mg/kg) or s.c. 5-HTP (100 mg/kg plus carbidopa. 12.5 mg/kg), the same s.c. doses of (+)WAY100135 did not modify their inhibitory effect on ethanol and food consumption. Present findings suggest that blockade either of pre- or of pre- and postsynaptic 5-HT1A receptors does not potentiate the inhibitory effect of fluoxetine or 5-HTP on ethanol and food intake.

5-Hydroxytryptophan↗