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PubMed2003

Molecular interactions between an insect predator and its herbivore prey on transgenic potato expressing a cysteine proteinase inhibitor from rice.

Transgenic plants expressing resistance to herbivorous insects may represent a safe and sustainable pest control alternative if they do not interfere with the natural enemies of target pests. Here we examined interactions between oryzacystatin I (OCI), a proteinase inhibitor from rice genetically engineered into potato (Solanum tuberosum cv. Kennebec, line K52) to increase resistance to insect herbivory, and the insect predator Perillus bioculatus. This stinkbug is a relatively specialized predator of caterpillars and leaf-beetle larvae, and may also include plant sap in its predominantly carnivorous diet. One of its preferred prey is Colorado potato beetle (Leptinotarsa decemlineata), a major target of insect resistance development for potato field crops. Gelatin/sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that a major fraction of proteinase (gelatinase) activity in P. bioculatus extracts is OCI-sensitive. Among five gelatinolytic bands detected, the slowest-moving one (proteinase I) was inhibited strongly by purified OCI expressed in Escherichia coli or by OCI-transgenic potato extracts, while three other proteinases were partly sensitive to these treatments. There was also evidence of slight inhibition of proteinase I by untransformed potato foliage, suggesting the presence of a natural inhibitor related to OCI at low level in potato foliage. Interestingly, only about 50% of the maximum potential activity of proteinase I was recovered in extracts of P. bioculatus feeding on L. decemlineata larval prey on a diet of OCI-potato foliage, indicating that the predator was sensitive to OCI in the midgut of its prey. However, P. bioculatus on OCI-prey survived, grew and developed normally, indicating ability to compensate prey-mediated exposure to the OCI inhibitor. Confinement of P. bioculatus to potato foliage provided no evidence that potato plant-derived nutrition is a viable alternative to predation, restriction to potato foliage in fact being inferior to free water for short-term survival of nonfeeding first-instar larvae. These results support the view that OCI, an effective inhibitor of a substantial fraction of digestive enzymatic potential in P. bioculatus, should not interfere with its predation potential when expressed in potato plants fed to its prey at a maximum level of approximately 0.8% of total soluble proteins in mature foliage.

Animals↗
PubMed2005

Laboratory studies of the effects of reduced prey choice caused by Bt plants on a predatory insect.

Crops transformed to express Bacillus thuringiensis (Bt) toxins can cause close to 100% mortality of certain target pest species. This study assessed the effect of target pest reduction on the predatory insect Chrysoperla carnea (Stephens) in the presence of alternative prey. Numbers of lacewings recovered from Bt oilseed rape (cultivar Oscar, event O52) did not differ significantly from numbers of lacewings recovered from conventional oilseed rape in cage experiments with the target pest Plutella xylostella (Linnaeus) and the non-target pest Myzus persicae (Sulzer) when aphid densities were high. However, significantly fewer lacewings were recovered from Bt plants as aphid densities were lowered. Lacewing weights were not affected by plant type.

Animals↗
PubMed2005

The SYNCAN project: goals, set-up, first results and settings of the human intervention study.

Experimental evidence on the anticancer properties of dietary prebiotics such as chicory inulin and oligofructose and dietary probiotics has accumulated in recent years. Various experimental models ranging from chemoprevention studies, tumour implantation models to genetically modified mice models, etc. have systematically shown the protective effects of these food ingredients. In some studies it appeared that synbiotics (combination of pre- and probiotics) exerted synergistic activity against processes of carcinogenesis. The logical next step in research was to find out if these observations also would be valid for human volunteers. This was the principal goal of the EU-sponsored SYNCAN project (QLK1-1999-346) which involved the integration of an in vitro study to select the most suitable synbiotic preparation, the application of this synbiotic in an in vivo rat model of chemically induced colon cancer, and, as the heart of the project, the investigation of the synbiotic effects in a human intervention study. The in vitro tests consisted of fermentation studies where the interaction of pre- and probiotics was studied. Cell-free supernatants were generated from various synbiotic combinations fermented by faecal slurry, which were then used to optimise a series of bioassays. In the rat study the anticarcinogenic effect of prebiotics and synbiotics but not of probiotics was demonstrated. Using tissue samples generated in this model, attempts were made to gain a better insight into the mechanisms underlying cancer development. The human intervention study consisted of two groups of volunteers. One group was composed of people at high risk (polypectomised subjects) for colon cancer and the other of volunteers (colon cancer subjects) who had previously undergone 'curative resection' for colon cancer but were not currently receiving treatment. The present paper describes the experimental design of the SYNCAN study, and demonstrates a functional effect of the synbiotic preparation (probiotic survival during gastrointestinal transit and modification of the intestinal flora). Detailed experimental outcome of the human intervention study will be reported elsewhere.

Animals↗
PubMed2003

Engineering plants for animal feed for improved nutritional value.

Feed formulation to meet nutritional requirements of livestock is becoming increasingly challenging. Regulations have banned the use of traditional high-quality protein supplements such as meat-and-bone meal, pollution from animal excreta of N and P is an issue and antibiotics are no longer available as insurance against the impact of enteric infection and feed anti-nutritional factors. The improved genetic potential of livestock is increasing daily requirement for energy and protein (essential amino acids). To benefit from the enhanced growth potential of livestock diets with high nutrient density are needed that can be formulated from crops without increased cost. Genetic modification of commodity crops used to manufacture animal feed in order to improve the density and quality of available nutrients is a potential solution to some of these problems. Furthermore, crops may be used as biofactories to produce molecules and products used in animal feed with considerable reductions in manufacturing fixed costs. Nevertheless, there are considerable not insurmountable challenges, such as the creation of sufficient economic value to deliver benefit to all members in the feed production chain, which is an essential element of identity preserving and delivering the technology to livestock producers. Individual output traits in the major commodity crops may not provide sufficient value to adequately compensate all the members of the feed production chain. Successful adoption of output traits may rely on inserting combinations of agronomic input traits with specific quality traits or increasing the value proposition by inserting combinations of output traits.

Animal Feed↗
PubMed1996

Recombinant human milk proteins - an opportunity and a challenge.

Several human milk proteins have physiologic functions in infants. These proteins are involved in defense against infectious agents and in the optimization of nutrient uptake from milk. Therefore, interest in producing recombinant human milk proteins to use in infant formula has been growing. Microorganisms and transgenic animals can now be used for the production of bioactive proteins. However, the benefits of each protein must be evaluated in cells, animal models, and infants before claims can be made that adding them to formula improves the health or nutrition of infants. Once benefits are shown, proper manufacturing conditions must be developed for introducing the protein or proteins into formula. Processing conditions must be evaluated to ensure that biologic activity is maintained. Dry blending, aseptic processing, sterile filtration, and other techniques will likely be necessary for introducing proteins that require specific tertiary structure for activity. The importance of posttranslational modifications must also be considered: some proteins may require proper glycosylation or phosphorylation for physiologic activity.

Animals↗
PubMed2000

A Caenorhabditis elegans MAP kinase kinase, MEK-1, is involved in stress responses.

The c-Jun N-terminal kinase (JNK), a member of the mitogen-activated protein kinase (MAPK) family, was shown to be involved in the response to various stresses in cultured cells. However, there is little in vivo evidence indicating a role for a JNK pathway in the stress response of an organism. We identified the Caenorhabditis elegans mek-1 gene, which encodes a 347 amino acid protein highly homologous to mammalian MKK7, an activator of JNK. Mek-1 reporter fusion proteins are expressed in pharyngeal muscle, uterus, a portion of intestine, and neurons. A mek-1 deletion mutant is hypersensitive to copper and cadmium ions and to starvation. A wild-type mek-1 transgene rescued the hypersensitivity to the metal ions. Double mutants of mek-1 with an eat-5, eat-11 or eat-18 mutation, which are characterized by a limited feeding defect, showed distinct growth defects under normal conditions. Expression of an activated form of MEK-1 in the whole animal or specifically in the pharynx inhibited pharyngeal pumping. These results suggest a role for mek-1 in stress responses, with a focus in the pharynx and/or intestine.

Amino Acid Sequence↗
PubMed1993

Commercialization of genetically engineered crops.

More abundant harvests from insect- and disease-resistant crops, vine-ripened tomatoes, or less oily potato chips or french fries are some of the benefits that will result from single gene improvements under development today. These single gene traits will be combined with the best new varieties produced by traditional plant breeding and will accelerate the pace and the scope of our ability to develop even better and more productive crops in the future. The initial group of genetic improvements were first field tested in 1987, improved upon over the past 6 years, and are finally approaching the first commercial sales over the next 3 to 4 years. The key hurdles from discovery of a promising lead to a commercial product trait include: (i) gene cloning and expression; (ii) product development; (iii) field testing; (iv) breeding into multiple elite varieties; (v) product characterization and regulatory review; (vi) public acceptance; and (vii) marketing. The expense and risk to bring transformed crops to market successfully is significantly higher than for traditionally developed new varieties. The high value of some single gene targets and the possibility for patent protection of the processes and final products provide the incentive for private investment in this area. The value to farmers, consumers, the environment and society in general is very high because the problems being solved are those that have resisted previous attempts through conventional means. Public investment in basic plant science research and private investment in product development is a powerful combination for continual improvement in lowering the cost and improving the quality of the world's food supply.

Agriculture↗
PubMed2005

Uptake of Bt endotoxins by nontarget herbivores and higher order arthropod predators: molecular evidence from a transgenic corn agroecosystem.

The planting of transgenic crops expressing Bacillus thuringiensis endotoxins is widespread throughout the world; the prolific increase in their application exposes nontarget organisms to toxins designed to control pests. To date, studies have focused upon the effects of Bt endotoxins on specific herbivores and detritivores, without consideration of their persistence within arthropod food webs. Here, we report the first quantitative field evaluation of levels of Bt endotoxin within nontarget herbivores and the uptake by higher order arthropods. Antibody-based assays indicated significant quantities of detectable Cry1Ab endotoxin within nontarget herbivores which feed on transgenic corn (including the corn flea beetle, Chaetocnema pulicaria, Japanese beetle, Popillia japonica and southern corn rootworm, Diabrotica undecimpunctata howardi). Furthermore, arthropod predators (Coccinellidae, Araneae, and Nabidae) collected from these agroecosystems also contained significant quantities of Cry1Ab endotoxin indicating its movement into higher trophic levels. This uptake by predators is likely to have occurred by direct feeding on plant material (in predators which are facultatively phytophagous) or the consumption of arthropod prey which contained these proteins. These data indicate that long-term exposure to insecticidal toxins occurs in the field. These levels of exposure should therefore be considered during future risk assessments of transgenic crops to nontarget herbivores and arthropod predators.

Agriculture↗
PubMed2002

Food biotechnology and nutrition in Africa: a case for Kenya.

Household food consumption surveys indicate that the diet in Kenya is ill balanced and that many families cannot afford nutrient-rich foods such as meat and fruits. In this regard, rural populations-the majority of the Kenyan population-are much worse off than urban populations. Agriculture, the most important sector in the Kenyan economy, contributes 27% of the gross domestic product and generates 65% of the country's export earnings. Food-enhancing biotechnologies thus could increase national food yields and fill nutrition gaps by contributing to household and national food security and poverty reduction in Kenya. To overcome barriers to adopting biotechnology to improve food crops in Kenya and elsewhere in Africa, policy makers must create a receptive environment for, increase public understanding of, and stimulate investment in the new technology.

Agriculture↗
PubMed2003

Safety assessment of foods produced through agricultural biotechnology.

Often the main criticism of foods derived from biotechnology is concerns about food safety. Whereas most present-day biotechnology-derived foods are approximately 99% similar to their non-biotechnology counterparts, the scientific community must ensure the safety of the novel aspects of these foods. The three phases of safety assessment are discussed and the concept of substantial equivalence is explained.

Agriculture↗
PubMedDate not supplied

[Implications of transgenics for environmental and agricultural sustainability].

The potential risks of GMOs, their impact on human and animal health, and on the environment, as well as their socioeconomic effects, have generated a worldwide discussion which is far from drawing to a close for lack of sufficient information. Part of this information supports risk-hypotheses previously put forward. Thus the presence of transgenic plant genes in other plants and in other organisms has been confirmed in several occasions. Therefore, gene dissemination to plants of the same species as well as to widely different species is already regarded as an actual risk. The principle of substantial equivalence has opened the way for the liberation of transgenic plants for commercial crops, despite short-term tests, which are quantitatively and qualitatively insufficient to certify that the foods deriving from those plants are healthy and safe. Thus, the adoption of the so-called precautionary principle (PP) has turned out to be the most adequate safety measure to date, or else until scientific data should be able to demonstrate the actual impact of transgenic plants on human and animal health, and on the environment.

Agriculture↗
PubMed2001

[A detection method for recombinant DNA from genetically modified maize CBH351].

A method using polymerase chain reaction (PCR) was designed for the detection of genetically modified maize CBH351, which has not authorized as safe for use in foods and feeds in Japan yet. We analyzed a recombinant DNA (r-DNA) sequence introduced into CBH351 maize and designed specific primer pairs to amplify a segment including part of the r-DNA. The PCR products obtained by using the designed primer pairs are specific for CBH351 and should prevent false positive results caused by other maizes and other main cereal crops. The r-DNA introduced into CBH351 could be detected from maize samples containing 0.05-0.1% CBH351 maize. This sensitivity is theoretically equivalent to a level of several genome copies and so this technique is a very efficient means to detect CBH351 maize.

DNA Primers↗
PubMed2003

Identification and quantification of carotenoids, tocopherols and chlorophylls in commonly consumed fruits and vegetables.

The carotenoid, tocopherol and chlorophyll metabolic profiles and content of a selection of fruits and vegetables found commonly in the diet, have been determined using a rapid RP-HPLC technique with on-line PDA detection. Information gathered from the screening of secondary plant metabolites is vital for the accurate determination of the dietary intake of these micro-nutrients, and in the development of comprehensive food tables. Determination of basal levels is also necessary for the rational engineering of health-promoting phytochemicals in food crops. In addition this approach can also be applied to the routine screening of products to determine metabolic differences between varieties and cultivars, as well as between genetically modified and the corresponding non-genetically modified tissue.

Carotenoids↗
PubMed2001

Electrochemical biosensors for evaluation of contaminants in food.

This paper describes the application of electrochemical disposable biosensors in food analysis, which have recently been developed in our laboratory. Disposable biosensors, based on acetylcholinesterase inhibition activity, were exploited for testing the presence of organophosphorus and carbamate pesticides in water, fruit, and vegetable samples. The paper further describes preliminary tests for the detection of genetically modified organisms and hybridisation by coupling the DNA biosensors with the polymerase chain reaction.

Biosensing Techniques↗
PubMed2004

Detection of genetically modified soybean using peptide nucleic acids (PNAs) and microarray technology.

Peptide nucleic acid (PNA) microarrays for the detection of Roundup Ready soybeans in food have been prepared. PNA probes are known to be more efficient and selective in binding DNA sequences than the analogous oligonucleotides and are very suitable to be used for diagnostics in food. PNAs of different lengths were carefully designed and synthesized by solid-phase synthesis on an automatic synthesizer adopting the BOC strategy. PNAs were purified by HPLC and characterized by HPLC/MS. The probes were spotted on a functionalized surface to produce a microarray to be hybridized with PCR products. DNA extracted from reference material was amplified using Cy3- and Cy5-labeled primers, and the fluorescent PCR products obtained were hybridized on the microarray. Two protocols were adopted: the hybridization with dsDNA or with ssDNA obtained by digestion with the enzyme lambda exonuclease. The best results were obtained using a 15-mer PNA probe in combination with the ssPCR product derived from enzymatic digestion. The method was applied to the analysis of a sample of certified transgenic soybean flour.

DNA, Plant↗