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PubMed2000

Biotechnology-based foods: is there a third way between the precaution principle and an overly enthusiastic dissemination of GMO?

The demand for consumer safety with regard to the food-processing industry is becoming, legitimately, more and more urgent. If ingested drugs can carry deleterious effects that exceed the beneficial effect that the research was initially undertaken for, then the same can only be the case for foods that stem from the same new biotechnologies, zero risk being non existent.

Consumer Product Safety↗
PubMed2001

Pest insect control in organically-produced crops of field vegetables.

In the UK, the demand for organic vegetable and salad crops is increasing, mainly as a result of the requirements of the multiple retailers. However, approximately 85% of the organic fruit and vegetable produce sold in the UK is imported. A major constraint to growing field vegetable crops, and particularly organically-produced crops, is the reduction in crop yield and quality caused by pest insects. This paper will consider the control techniques currently available to organic growers and other techniques that may become available in the future. Growing plant varieties with complete or even partial resistance to pest insects can be an effective way of reducing crop damage. There are already varieties of carrot, with resistance to carrot fly, and lettuce, with resistance to certain pest aphid species, which are available commercially. Cultural techniques to exclude, deter or avoid pest insects are also being used by some organic growers. Although isolating new crops from sources of infestation can be a highly effective control strategy, many organic growers cannot use it, as the land converted for organic production is still limited. Various crop covers can be used to prevent pest insects from damaging field crops, but to be effective such covers have to be in place before the pests enter the crop. Several researchers have tried to develop techniques to prevent pest insects from finding their host-plants. No technique involving semiochemicals has been sufficiently successful to be used in field vegetable production in the UK. Other studies have shown that the numbers of pest insects found on crop plants are reduced considerably when the crop is allowed to become weedy, is intercropped with another plant species, or is undersown with a living mulch. Hence, work is now needed to select background plant species that will both reduce pest insect numbers and cause the least reduction in yield to the harvested crop plants. There is also a need to obtain a better understanding of "companion planting", a practice used frequently by organic growers. To date, microbial control is the only biological technique that has been used successfully in field vegetable crops in the UK. However, only the toxicant produced by one microbial agent, the bacterium Bacillus thuringiensis, has so far been registered for use. The use of bacteria, fungi and viruses to control pests of field vegetable crops certainly has possibilities. However, in many cases there are still problems to be overcome to select pathogens that are compatible with, or can still be effective in, the wide fluctuations in temperature, humidity and soil moisture that occur under field conditions. Attempts are now being made to use entomopathogenic nematodes and predatory arthropods to control one major pest insect, the cabbage root fly. Techniques developed to improve the timing of application of various crop protection procedures in systems of conventional vegetable production apply equally well to organic production, despite the choice of control options being more limited. In particular, models to forecast the timing of pest insect attacks could be used to great effect, to indicate the best times to plant, protect and harvest a specific crop to minimise pest insect damage.

Agriculture↗
PubMed2001

Wheat transformation with glutenin gene.

The rheological properties of wheat grains are associated with the composition of the starchy endosperm in high molecular weight (HMW) glutenin proteins. The HMW glutenin 1xDy12 subunit gene was co introduced with the screenable bar and the reporter gus marker genes in the commercial spring wheat Minaret cultivar (cv). The gene of interest and the marker genes were carried by two separated plasmids, the pBS10BH1 and the pAhC25 respectively. Seven days old calli initiated from immature embryos were bombarded by use of the PDS-1000/He device. A number of different bombardment and culture conditions were tested. These parameters were evaluated on the basis of GUS transient expression. Among those a 4 degrees C cold pre-treatment of the spikes before immature embryos were excised, the culture medium incorporating activated charcoal, silver nitrate and glucose yielded higher GUS transient expression rate. The selective agent bialaphos was maintained at various stages during culture from induction of somatic embryogenesis to rooting of regenerated plantlets. 137 bialaphos resistant plants were obtained among which 109 were carried to maturity. Transgenic plants were characterized by PCR, Southern and SDS-PAGE analysis of the glutenin content.

Biotechnology↗
PubMed2002

Biotechnology-derived nutritious foods for developing countries: needs, opportunities, and barriers: discussion summary.

Improvements in diet diversification and quality can be facilitated by greater cooperation between the agricultural and the nutrition communities, according to an expert panel that met in early 2002. Encouraged to think innovatively, the panelists agreed that modern technology offers the potential to increase the amount and nutritional content of the food supply in developing countries, especially if the enhancements are made to the highest-yielding indigenous staple crops and if a total food-systems approach is taken. All types of interventions should be evaluated for their cost-effectiveness in preventing nutritional deficiencies in the developing world and for their sustainability.

Agriculture↗
PubMed2004

Influence of cooking and microwave heating on microstructure and mechanical properties of transgenic potatoes.

The transgenic potato clones of cultivar Irga with improved resistance to a necrotic strain of potato virus Y (PVY(N)) were subjected to heat treatment in order to determine their technological quality. The technological quality was determined on the basis of differences between mechanical properties of unmodified potato and transgenic clones during cooking and microwave heating. The compression test was applied in order to evaluate the mechanical resistance of raw, cooked and microwave-treated potatoes. Compression resistance was expressed by fracture stress F (kPa), fracture strain D (mm/mm), and Young modulus E (kPa). The differences in microstructure of potato tubers (unmodified and modified) were investigated using scanning electron microscopy (SEM). The observed differentiation in the mechanical properties of heat-treated potatoes was less connected with genetic modification but most of all with a kind of the process used. The heat processes caused a distinct decrease in mechanical resistance in all the examined tubers. However, the process of microwave heating resulted in more significant changes in mechanical properties of tubers than cooking. Deformation of parenchyma cells during cooking was directly connected with starch, gelatinisation and gel formation. Microwave heating affected significantly cellular water evaporation which resulted in intercellular failure, collapsing of cells, and limitation of starch gelatinisation.

Cooking↗
PubMed2000

Safety assessment of rice genetically modified with soybean glycinin by feeding studies on rats.

Feeding studies on rice genetically modified with soybean glycinin were performed on rats for four weeks. The rats were divided into three groups, each being fed on (I) only a commercial diet, (II) this diet plus control rice and (III) this diet plus rice genetically modified with glycinin. The rats were fed with 10 g/kg-weight of rice every day by oral administration. During the test period, the rats in every group grew well without marked differences in appearance, food intake, body weight, or cumulative body weight gain. There were also no significant differences in the blood count, blood composition or internal organ weights among the rats. Necropsy at the end of the experiment indicated neither pathological symptoms nor histopathological abnormalities in the liver and kidney. Judging from these results, the rice genetically modified with glycinin is considered to have been essentially the same in nutritional and biochemical characteristics as the control rice.

Animal Feed↗
PubMed2001

Dietary diversification/modification strategies to enhance micronutrient content and bioavailability of diets in developing countries.

Both cereal staples and household diets can be manipulated to enhance the content of micronutrients and/or alter the levels of absorption modifiers to improve micronutrient bioavailability. Strategies described range from plant breeding, use of fertilizers and genetic engineering to changes in food preparation and processing methods at the household level involving soaking, fermentation and germination. The impact of five household strategies designed to enhance the content and bioavailability of iron, zinc and calcium in a representative daily menu for rural Malawian preschool children has been calculated using food composition data. In the five strategies, relishes based on small dried fish replaced plant-based relishes, maize-based porridges prepared with maize flour soaked to reduce its hexa (IP-6)- and penta (IP-5)-inositol phosphate content replaced conventional porridges; and a pumpkin-leaf relish replaced sweet potato to increase the retinol content of the daily menu. Comparison of the calculated energy, nutrient, and phytate content, and [phytate]:[zinc] molar ratios of the five modified menus compared with the unmodified menu emphasizes that to ensure that the estimated requirements for iron and zinc are met, the optimal strategy includes dried fish relish twice daily together with porridges prepared using soaked (or fermented) maize flour to reduce their hexa- and penta-inositol phosphate content. Implementation of these household strategies has the potential to increase the bioavailability of iron and zinc in rural Malawian diets from low to high.

Animals↗
PubMed2002

[Transgenes and their medical applications].

Transgenesis consists of introducing stably a foreign genetic information into the genome of a multicellular organism. These techniques used for the first time in 1980 for the animals and 1983 for plants have multiple applications of which many are directly or not related to medicine. Transgenesis has become one of the essential tools to study the role of genes in the control of biological functions. This approach is logically accompanied by the generation of transgenic animal lines for the study of human diseases and the test of new pharmaceuticals. Milk from transgenic animals as well as leaves and seeds from transgenic plants are ready to become an essential source of proteins having essential therapeutical effects. Genetically modified pigs are expected to be resistant to rejection mechanisms to become the source of organs or cells for patients. The application of transgenesis in agriculture and breeding is still in infancy. It may contribute quite significantly to provide human communities with food in sufficient amount, having improved nutritional properties and produced using a milder and less polluting methods.

Agriculture↗
PubMed2004

Safe and acceptable strategies for producing foreign molecules in plants.

The ability to express foreign genes using transgenic technologies has opened up options for producing large quantities of commercially important industrial or pharmaceutical products in plants. These technologies have made it possible to use well-developed systems of commercial agriculture that were developed principally to produce raw material for large-scale food, feed or processing applications for the production of foreign molecules. The possibility of the novel industrial or pharmaceutical molecules produced in such plants, or components derived from them, contaminating the environment and food chains has become especially controversial. This potential contamination has prompted detailed consideration of how such crops and the molecules that they produce can be effectively isolated and contained. First, the crop can be completely isolated physically from its food or feed counterpart during every aspect of its development and commercialization. Second, genetic isolation systems or genetic barriers that prevent normal reproduction can be used to reduce the likelihood of the industrial or pharmaceutical crop entering the food chain.

Biotechnology↗
PubMed2001

Metal-binding proteins and peptides in bioremediation and phytoremediation of heavy metals.

The expression of metal-binding proteins or peptides in microorganisms and plants in order to enhance heavy metal accumulation and/or tolerance has great potential. Several different peptides and proteins have been explored. This review focuses on cadmium (Cd) because of the significant importance of this metal and because of its global presence in many food materials.

Metals, Heavy↗
PubMed2006

Production and processing of milk from transgenic goats expressing human lysozyme in the mammary gland.

The potential for applying biotechnology to benefit animal agriculture and food production has long been speculated. The addition of human milk components with intrinsic antimicrobial activity and positive charge to livestock milk by genetic engineering has the potential to benefit animal health, as well as food safety and production. We generated one line of transgenic goats as a model for the dairy cow designed to express human lysozyme in the mammary gland. Here we report the characterization of the milk from 5 transgenic females of this line expressing human lysozyme in their milk at 270 microg/mL or 68% of the level found in human milk. Milk from transgenic animals had a lower somatic cell count, but the overall component composition of the milk and milk production were not different from controls. Milk from transgenic animals had a shorter rennet clotting time and increased curd strength. Milk of such nature may be of benefit to the producer by influencing udder health and milk processing.

Animals↗
PubMed1995

Genetic engineering of foods to reduce the risk of heart disease and cancer.

Gene manipulation techniques can be used to increase, decrease, or add specific proteins to the edible parts of transgenic crop plants. With some basic understanding of plant biosynthetic pathways, then, the targeting of genes encoding specific enzymes allows the direct modification of the biochemical composition of foods. At Calgene, we have engineered the chemical composition of canola vegetable oils. Transgenic canola which are otherwise exactly like regular canola plants produce seed with oils a) that are modified in average fatty acid carbon chain length, b) that are modified in content of saturated fatty acids (both lower and higher), or c) that contain structured lipids. In principle, although the gene target may not be obvious, the relative amount of lipids compared to other nutrients can be decreased or increased in foods like peanut or soybean. The oil content of some food products might be modified to enhance levels of medium chain triglycerides or to contain "fish oil" fatty acids--without the cost or olfactory disadvantages. On a broader scope, the amino acid composition of proteins in basic grains is being pursued by several groups. Specific vitamin contents such as Vitamin A or E might be enhanced in basic foodstuffs; type and content of fiber may eventually be manipulated. Specific components such as caffeine or phytic acid conceivably can be eliminated in the source plant, negating the need for processing steps that add cost and that lessen flavor and nutrition. Clearly, the biochemical compositions of foods is complex and varied. Moreover, tailoring foods to better meet our needs is an expensive and lengthy process. The best possible understanding of how nutrition promotes good health is necessary to direct and prioritize our efforts to improve plants as food sources.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Mice lacking dopamine D1 receptors express normal lithium chloride-induced conditioned taste aversion for salt but not sucrose.

Conditioned taste aversion (CTA), is a form of Pavlovian learning wherein a novel flavour is powerfully associated with subsequent feelings of illness, and is afterwards avoided. In rats, pharmacological blockade of dopamine D1 receptors has been reported to prevent the expression of a CTA to the sweet taste of sucrose or saccharine. We used genetically modified mice to determine whether dopamine D1 receptors are necessary for the expression of a CTA. Food-deprived mice lacking the dopamine D1 receptor (D1r-/-) did not express a LiCl-induced (125 or 254 mg/kg) CTA to the sweet taste of 0.5 m sucrose, in agreement with previous pharmacological studies. However, water-deprived D1r-/- mice did express normal LiCl-induced (40, 150 and 254 mg/kg) CTA to a salty taste (0.2 m NaCl). Our results suggest that activation of D1 receptors might contribute to the strength of an aversive gustatory association, but might not be required for the formation of a CTA in general.

Animals↗
PubMed2000

Attitudes of the public and scientists to biotechnology in Japan at the start of 2000.

This survey on biotechnology and bioethics was carried out on national random samples of the public and scientists in November 2000-January 2000 [sic]throughout Japan, and attendees at the Novartis Life Science Forum held on 29 September 1999 in Tokyo. The sample size was 297, 370, and 74 respectively. While there is a better awareness of GMOs in 2000 compared to 1991; the trend shows an increase in the perceived risks of GMOs followed by growing resistance in Japan. While a majority of persons believed genetic engineering would make life better over the next twenty years (57%), the proportion of respondents who thought genetic engineering would make life worse over the next twenty years doubled from 1997 to 2000 (from 12% to 25%). Respondents were asked whether they had heard about applications in several areas and the order of familiarity (high-low) was: pest-resistant crops, human genes in bacteria, mouse to develop cancer, food and drinks, pigs with human hearts and pre-implantation diagnosis. A divide of opinion can be seen when the results on benefit, risk and moral acceptability of applications of biotechnology by the public are compared to the forum and scientist samples. A significant change in the acceptance of the public occurred in 2000 where only 22% agreed on the moral acceptability of GM food compared to 41% in 1997. In 2000 fewer people said they are willing (20%) to buy genetically modified fruits that taste better compared to 1997 (36%). The results show less public support for use of gene therapy than 1993 and twice as many scientists rejected gene therapy than they did in 1991. When asked who is best placed to regulate modern biotechnology, the respondents were overwhelmingly in favor of international regulatory bodies, such as the United Nations and the World Health Organization (72%), rather than national bodies. The comparison between scientists and public is interesting, however the more enthusiastic sample were participants from the Novaritis Life Science Forum with its mixed occupations.

Biotechnology↗
PubMed2001

Evaluating the safety of microbial enzyme preparations used in food processing: update for a new century.

Microbial enzymes used in food processing are typically sold as enzyme preparations that contain not only a desired enzyme activity but also other metabolites of the production strain, as well as added materials such as preservatives and stabilizers. The added materials must be food grade and meet applicable regulatory standards. The purpose of this report is to present guidelines that can be used to evaluate the safety of the metabolites of the production strain that are also present in the enzyme preparation, including of course, but not limited to, the desired enzyme activity itself. This discussion builds on previously published decision tree mechanisms and includes consideration of new genetic modification technologies, for example, modifying the primary structure of enzymes to enhance specific properties that are commercially useful. The safety of the production strain remains the primary consideration in evaluating enzyme safety, in particular, the toxigenic potential of the production strain. Thoroughly characterized nonpathogenic, nontoxigenic microbial strains, particularly those with a history of safe use in food enzyme manufacture, are logical candidates for generating a safe strain lineage, through which improved strains may be derived via genetic modification by using either traditional/classical or rDNA strain improvement strategies. The elements needed to establish a safe strain lineage include thoroughly characterizing the host organism, determining the safety of all new DNA that has been introduced into the host organism, and ensuring that the procedure(s) that have been used to modify the host organism are appropriate for food use. Enzyme function may be changed by intentionally altering the amino acid sequence (e.g., protein engineering). It may be asked if such modifications might also affect the safety of an otherwise safe enzyme. We consider this question in light of what is known about the natural variation in enzyme structure and function and conclude that it is unlikely that changes which improve upon desired enzyme function will result in the creation of a toxic protein. It is prudent to assess such very small theoretical risks by conducting limited toxicological tests on engineered enzymes. The centerpiece of this report is a decision tree mechanism that updates previous enzyme safety evaluation mechanisms to accommodate advances in enzymology. We have concluded that separate mutagenicity testing is not needed if this decision tree is used to evaluate enzyme safety. Under the criteria of the decision tree, no new food enzyme can enter the market without critical evaluation of its safety.

Animals↗
PubMed1991

Biological membrane deterioration and associated quality losses in food tissues.

Biological membranes are rarely considered by food scientists when the deteriorative reactions that take place during the processing or storage of food tissues are studied. Yet, membranes and their deterioration play a major but underestimated role in food losses, and recent biochemical information indicates that at least some of these reactions can be controlled by procedures suited to food materials. Much of the present information available on membrane degradation in food systems is incomplete and speculative. It is known, however, that in order to accomplish their many indispensable functions in cells, membranes are constituted mainly of phospholipids, protein, and some carbohydrates arranged in thin, bimolecular sheet-like structures that serve to compartmentalize cells and their organelles. Membranes have embedded in their asymmetric surfaces complements of catalytic and cytoskeletal proteins that serve permeability and structural functions. Membrane surfaces exhibit fluidity, due partially to the continuous lateral diffusion of lipids and some proteins. Two important consequences of fluidity are the ability of membrane phospholipids to exist in different interconvertible conformational phase structures and the formation of heterogenous lipid domains on the membrane surface. Cellular death leads unavoidably to the initiation of membrane deterioration. While the time course of this series of reactions differs in animal and plant tissue, they are damaged by generally similar mechanisms. These include an initial peroxidative attack on polyunsaturated fatty acids, with the concomitant production of free radicals. Many biological agents can act as accelerating agents in these reactions, including transition metal ions, heme compounds, radiation, illuminated chlorophyll, calcium, and ethylene. Once formed, free radicals catalyze further reactions that can affect all aspects of membrane function and cellular metabolism, and lead ultimately to significant losses in food quality through defects such as chilling injury and cold shortening. These are aggravated by many food-processing steps, especially those that involve tissue disruption. Control of membrane breakdown by exogenous chemical intervention has been practiced, but, at best, this only slows the rate of these reactions. Newer approaches to this problem include dietary treatment of meat animals, modified storage and packaging conditions, and genetic interventions. This review advances the proposition that membrane deterioration can be considered a "universal mechanism" that leads to significant quality losses in food. Perhaps because the study of biological membranes and the biochemical and physiological properties has only begun recently, not much progress has been made in finding practical control mechanisms for these reactions in food systems.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗