Degradation of transgenic Cry1Ab DNA and protein in Bt-176 maize during the ensiling process

Scientific Opinion on application EFSA-GMO-BE-2013-117 for authorisation of genetically modified maize MON 87427 × MON 89034 × NK603 and subcombinations independently of their origin, for food and feed uses, import and processing submitted under Regulation (EC) No 1829/2003 by Monsanto Company

In this opinion, the EFSA Panel on Genetically Modified Organisms (GMO Panel) assessed the three-event stack maize MON 87427 × MON 89034 × NK603 and its three subcombinations, independently of their origin. The GMO Panel has previously assessed the three single events combined to produce this three-event stack maize and did not identify safety concerns. No new data on the single events, leading to modification of the original conclusions on their safety, were identified. Based on the molecular, agronomic, phenotypic and compositional characteristics, the combination of the single maize events and of the newly expressed proteins in the three-event stack maize did not give rise to issues regarding food and feed safety or nutrition. In the case of accidental release of viable grains of maize MON 87427 × MON 89034 × NK603 into the environment, the three-event stack maize would not raise environmental safety concerns. The GMO Panel concludes that the three-event stack maize is as safe and as nutritious as the non-GM comparator and the tested non-GM reference varieties in the context of its scope. The GMO Panel considered that its previous conclusions on the two-event stack maize MON 89034 × NK603 remain valid. For the two maize subcombinations for which no experimental data were provided the GMO Panel assessed the likelihood of interactions among the single events, and concluded that their combination would not raise safety concerns. These two subcombinations are therefore expected to be as safe as the single events, the previously assessed maize MON 89034 × NK603 and maize MON 87427 × MON 89034 × NK603. Since the post-market environmental monitoring plan for the three-event stack maize does not include any provisions for the two subcombinations not previously assessed, the GMO Panel recommended the applicant to revise the plan accordingly.

Scientific Opinion on application EFSA-GMO-BE-2013-118 for authorisation of genetically modified maize MON 87427 × MON 89034 × 1507 × MON 88017 × 59122 and subcombinations independently of their origin, for food and feed uses, import and processing submitted under Regulation (EC) No 1829/2003 by Monsanto Company

In this opinion, the GMO Panel assessed the five-event stack maize MON 87427 × MON 89034 ×1507 × MON 88017 × 59122 and its 25 subcombinations, independently of their origin. The GMO Panel has previously assessed the five single events combined to produce this five-event stack maize and 11 subcombinations of these events and did not identify safety concerns. No new data on the single events or their previously assessed subcombinations, leading to modification of the original conclusions were identified. The combination of the single events and of the newly expressed proteins in the five-event stack maize did not give rise to issues - based on the molecular, agronomic/phenotypic or compositional characteristics - regarding food and feed safety and nutrition. Considering the scope of this application, the known biological function of the newly expressed proteins and the data available for the five-event stack maize and its previously assessed maize subcombinations, the GMO Panel considered that different combinations of the single events would not raise environmental concerns. The GMO Panel concludes that the five-event stack maize is as safe and as nutritious as the non-genetically modified (GM) comparator and the tested non-GM reference varieties in the context of its scope. For the 14 maize subcombinations for which no experimental data were provided, the GMO Panel assessed the likelihood of interactions among the single events, and concluded that their combinations would not raise safety concerns. These maize subcombinations are therefore expected to be as safe as the single events, the previously assessed subcombinations and maize MON 87427 ×MON 89034 × 1507 × MON 88017 × 59122. Since the post-market environmental monitoring plan for the five-event stack maize does not include any provisions for the 14 maize subcombinations not previously assessed, the GMO Panel recommended the applicant to revise the plan accordingly.

Detection of dietary DNA, protein, and glyphosate in meat, milk, and eggs

Products such as meat, milk, and eggs from animals that have consumed genetically engineered (GE) feed are not currently subject to mandatory GE labeling requirements. Some voluntary "non-genetically modified organism" labeling has been associated with such products, indicating that the animals were not fed GE crops, as there are no commercialized GE food animals. This review summarizes the available scientific literature on the detection of dietary DNA and protein in animal products and briefly discusses the implications of mandatory GE labeling for products from animals that have consumed GE feed. Because glyphosate is used on some GE crops, the available studies on glyphosate residues in animal products are also reviewed. In GE crops, recombinant DNA (rDNA) makes up a small percentage of the plant's total DNA. The final amount of DNA in food/feed depends on many factors including the variable number and density of cells in the edible parts, the DNA-containing matrix, environmental conditions, and the specific transgenic event. Processing treatments and animals' digestive systems degrade DNA into small fragments. Available reports conclude that endogenous DNA and rDNA are processed in exactly the same way in the gastrointestinal tract and that they account for a very small proportion of food intake by weight. Small pieces of high copy number endogenous plant genes have occasionally been detected in meat and milk. Similarly sized pieces of rDNA have also been identified in meat, primarily fish, although detection is inconsistent. Dietary rDNA fragments have not been detected in chicken or quail eggs or in fresh milk from cows or goats. Collectively, studies have failed to identify full-length endogenous or rDNA transcripts or recombinant proteins in meat, milk, or eggs. Similarly, because mammals do not bioaccumulate glyphosate and it is rapidly excreted, negligible levels of glyphosate in cattle, pig and poultry meat, milk, and eggs have been reported. Despite consumer concern about the presence of trace concentrations of glyphosate that might have been applied to feed crops and/or the presence of rDNA or recombinant proteins in meat, milk, and eggs, the available data do not provide evidence to suggest that products from animals that have consumed approved GE feed crops differ in any distinguishable way from those derived from animals fed conventional feed or that products from animals fed GE feedstuffs pose novel health risks.

Degradation of endogenous and exogenous genes of genetically modified rice with Cry1Ab during food processing

In order to assess the degradation of endogenous and exogenous genes during food processing, genetically modified rice with Cry1Ab was used as raw material to produce 4 processed foods: steamed rice, rice noodles, rice crackers, and sweet rice wine. The results showed various processing procedures caused different degrees of degradation of both endogenous and exogenous genes. During the processing of steamed rice and rice noodles, the procedures were so mild that only genes larger than 1500 bp were degraded, and no degradation of NOS terminator and Hpt gene was detected. For rice crackers, frying was the most severe procedure, followed by microwaving, baking, boiling, 1st drying, and 2nd drying. For sweet rice wine, fermentation had more impact on degradation of genes than the other processing procedures. All procedures in this study did not lead to degradation of genes to below 200 bp, except for NOS terminator. In the case of stability of the genes studied during processing of rice crackers and sweet rice wine, SPS gene was the most, followed by the Cry1Ab gene, Hpt gene, Pubi promoter, and NOS terminator.

PRACTICAL APPLICATION

In our study, we gained some information about the degradation of endogenous and exogenous genes during 4 foods processing, compared the different stabilities between endogenous and exogenous genes, and analyzed different effects of procedure on degradation of genes. In addition, the fragments of endogenous and exogenous genes about 200 bp could be detected in final products, except NOS terminator. As a result, we provided some base information about risk assessment of genetically modified (GM) food and appropriate length of fragment to detect GM component in processed foods.

Fate of Cry1Ab protein in agricultural systems under slurry management of cows fed genetically modified maize (Zea mays L.) MON810: a quantitative assessment

The objective of the study was to track the fate of recombinant Cry1Ab protein in a liquid manure field trial when feeding GM maize MON810 to dairy cows. A validated ELISA was applied for quantification of Cry1Ab in the agricultural chain from GM maize plants, feed, liquid manure and soil to crops grown on manured fields. Starting with 23.7 μg of Cry1Ab g(-1) dry weight GM maize material, a rapid decline of Cry1Ab levels was observed as 2.6% and 0.9% of Cry1Ab from the GM plant were detected in feed and liquid manure, respectively. Half of this residual Cry1Ab persisted during slurry storage for 25 weeks. After application to experimental fields, final degradation of Cry1Ab to below detectable levels in soil was reported. Cry1Ab exhibited a higher rate of degradation compared to total protein in the agricultural processes. Immunoblotting revealed a degradation of the 65 kDa Cry1Ab into immunoreactive fragments of lower size in all analyzed materials.

Degradation of Cry1Ab protein from genetically modified maize (MON810) in relation to total dietary feed proteins in dairy cow digestion

To investigate the relative degradation and fragmentation pattern of the recombinant Cry1Ab protein from genetically modified (GM) maize MON810 throughout the gastrointestinal tract (GIT) of dairy cows, a 25 months GM maize feeding study was conducted on 36 lactating Bavarian Fleckvieh cows allocated into two groups (18 cows per group) fed diets containing either GM maize MON810 or nearly isogenic non-GM maize as the respective diet components. All cows were fed a partial total mixed ration (pTMR). During the feeding trial, 8 feed (4 transgenic (T) and 4 non-transgenic (NT) pTMR) and 42 feces (26 T and 18 NT) samples from the subset of cows fed T and NT diets, and at the end of the feeding trial, digesta contents of rumen, abomasum, small intestine, large intestine and cecum were collected after the slaughter of six cows of each feeding group. Samples were analyzed for Cry1Ab protein and total protein using Cry1Ab specific ELISA and bicinchoninic acid assay, respectively. Immunoblot analyses were performed to evaluate the integrity of Cry1Ab protein in feed, digesta and feces samples. A decrease to 44% in Cry1Ab protein concentration from T pTMR to the voided feces (9.40 versus 4.18 mug/g of total proteins) was recorded. Concentrations of Cry1Ab protein in GIT digesta of cows fed T diets varied between the lowest 0.38 mug/g of total proteins in abomasum to the highest 3.84 mug/g of total proteins in rumen. Immunoblot analysis revealed the extensive degradation of recombinant Cry1Ab protein into a smaller fragment of around 34 kDa in GIT. The results of the present study indicate that the recombinant Cry1Ab protein from MON810 is increasingly degraded into a small fragment during dairy cow digestion.

From milk to diet: feed recognition for milk authenticity

The presence of plastidial DNA fragments of plant origin in animal milk samples has been confirmed. An experimental plan was arranged with 4 groups of goats, each provided with a different monophytic diet: 3 fresh forages (oats, ryegrass, and X-triticosecale) and one 2-wk-old silage (X-triticosecale). Feed-derived rubisco (ribulose bisphosphate carboxylase, rbcL) DNA fragments were detected in 100% of the analyzed goat milk samples, and the nucleotide sequence of the PCR-amplified fragments was found to be 100% identical to the corresponding fragments amplified from the plant species consumed in the diet. Two additional chloroplast-based molecular markers were used to set up an assay for distinctiveness, conveniently based on a simple PCR. In one case, differences in single nucleotides occurring within the gene encoding for plant maturase K (matK) were exploited. In the other, plant species recognition was based on the difference in the length of the intron present within the transfer RNA leucine (trnL) gene. The presence of plastidial plant DNA, ascertained by the PCR-based amplification of the rbcL fragment, was also assessed in raw cow milk samples collected directly from stock farms or taken from milk sold on the commercial market. In this case, the nucleotide sequence of the amplified DNA fragments reflected the multiple forages present in the diet fed to the animals.

Testing for genetically modified organisms (GMOs): Past, present and future perspectives

This paper presents an overview of GMO testing methodologies and how these have evolved and may evolve in the next decade. Challenges and limitations for the application of the test methods as well as to the interpretation of results produced with the methods are highlighted and discussed, bearing in mind the various interests and competences of the involved stakeholders. To better understand the suitability and limitations of detection methodologies the evolution of transformation processes for creation of GMOs is briefly reviewed.

Persistence of plant DNA sequences in the blood of dairy cows fed with genetically modified (Bt176) and conventional corn silage

To determine whether plant sequences, including transgenic sequences, are present in animal blood, we tested blood samples from Holstein cows fed with either Bt176 genetically modified corn or conventional corn. We used previously described sensitive real-time PCR assays targeting transgenic sequences (35S promoter and Bt176 specific junction sequence), a monocopy maize-specific sequence (ADH promoter), and two multicopy sequences from plant nucleus (26S rRNA gene) and chloroplast (psaB gene). The presence of Cry1A(b) protein in bovine blood samples was also tested using a sandwich ELISA kit. Our study shows the ability of plant nuclear and/or chloroplast DNA fragments to enter bovine blood circulation. However, maize nuclear DNA, both mono- and multicopy sequences, was less detected than chloroplast DNA, probably because the higher number of chloroplast copies and also possibly because nuclear DNA might be less protected by the nuclear membrane. Despite our data confirm the ability of small (ca.150 bp) plant DNA fragments to cross the intestinal barrier, we were unable to demonstrate clearly the presence of transgenic DNA or proteins in bovine blood. No sample tested positive with the two real-time PCR assays targeting transgenic sequences (35S promoter and Bt176 specific junction sequence). Only faint punctual positive results occurred randomly and were probably due to postsample collection or laboratory contamination or can be considered as artifact as they have never been confirmed. Our data highlight the difficulties to detect transgenic sequences in blood of dairy cows fed genetically modified corn (Bt176) silage. Those results show that in order to meet the consumers' demand of animals fed with GM products there is currently no cost-effective analytical procedure to replace documentary traceability.

Effect of feeding cows genetically modified maize on the bacterial community in the bovine rumen

Rumen-cannulated cows (n = 4) were fed successively silage made from either conventional or genetically modified (GM) maize. Results revealed no effects of GM maize on the dynamics of six ruminal bacterial strains (investigated by real-time PCR) compared to the conventional maize silage.