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The ever-increasing production of genetically modified crops generates a demand for high-throughput DNA-based methods for the enforcement of genetically modified organisms (GMO) labelling requirements. The application of standard real-time PCR will become increasingly costly with the growth of the number of GMOs that is potentially present in an individual sample. The present work presents the results of an innovative approach in genetically modified crops analysis by DNA based methods, which is the use of a microfluidic dynamic array as a high throughput multi-detection system. In order to evaluate the system, six test samples with an increasing degree of complexity were prepared, preamplified and subsequently analysed in the Fluidigm system. Twenty-eight assays targeting different DNA elements, GM events and species-specific reference genes were used in the experiment. The large majority of the assays tested presented expected results. The power of low level detection was assessed and elements present at concentrations as low as 0.06 % were successfully detected. The approach proposed in this work presents the Fluidigm system as a suitable and promising platform for GMO multi-detection.

peer-reviewed Background: We aimed to determine the effect of feeding transgenic maize to sows during gestation and lactation on maternal and offspring immunity and to assess the fate of transgenic material. Methodology/Principal Findings: On the day of insemination, sows were assigned to one of two treatments (n = 12/treatment); 1) non-Bt control maize diet or 2) Bt-MON810 maize diet, which were fed for ~143 days throughout gestation and lactation. Immune function was assessed by leukocyte phenotyping, haematology and Cry1Ab-specific antibody presence in blood on days 0, 28 and 110 of gestation and at the end of lactation. Peripheral-blood mononuclear cell cytokine production was investigated on days 28 and 110 of gestation. Haematological analysis was performed on offspring at birth (n = 12/treatment). Presence of the cry1Ab transgene was assessed in sows' blood and faeces on day 110 of gestation and in blood and tissues of offspring at birth. Cry1Ab protein presence was assessed in sows' blood during gestation and lactation and in tissues of offspring at birth. Blood monocyte count and percentage were higher (P

In 2006 and 2007, field trials were performed to study the effects of the two isolation distances indicated by the Dutch Coexistence Committee, i.e., 25 m between GM (genetically modified) and conventional maize, and 250 m between GM and deliberately non-GM (e.g., organic) maize, on pollen-mediated gene flow (PMGF) under representative agricultural conditions in the Netherlands. Each isolation distance was tested at three different locations across the Netherlands in both years. For testing PMGF with the 25 m isolation distance, GM source fields of 100 m × 100 m (1 ha) were surrounded by four equally sized non-GM receptor fields at a distance of 25 m. For testing PGMF with the 250 m isolation distance, 1-ha GM source fields were surrounded by four 50 m × 50 m (0.25 ha) receptor fields in four different directions at 250 m. For the GM source field, the maize variety DKC3421YG containing the MON810 event was used with both distances. A maize variety near-isogenic to the GM variety was grown in the receptor fields to obtain good flowering synchronicity between GM and non-GM maize and thus optimal conditions for PGMF. Levels of the transgene in grain samples from the receptor fields were measured by a validated real-time PCR (polymerase chain reaction) quantification method for the MON810 event. Analyses showed the following levels of grain admixture as a consequence of PMGF, averaged over 12 fields for each isolation distance tested: at 25 m 0.084% (individual field averages ranged from 0.009%t0 0.296%) in 2006 and 0.080% (0.002% to 0.318%) in 2007, respectively, and at 250 m 0.005% (individual field averages ranged from o to 0.040%) in 2006 and 0.007% (0 to 0.037%) in 2007, respectively. Although weather conditions clearly differed between 2006 and 2007 (a hot and dry summer in 2006 vs. a relatively wet one with about-average temperatures in 2007), outcrossing rates did not differ significantly between these years.

To improve the efficacy of the in-house validation of GMO detection methods (DNA isolation and real-time PCR, polymerase chain reaction), a study was performed to gain insight in the contribution of the different steps of the GMO detection method to the repeatability and in-house reproducibility. In the present study, 19 methods for (GM) soy, maize canola and potato were validated in-house of which 14 on the basis of an 8-day validation scheme using eight different samples and five on the basis of a more concise validation protocol. In this way, data was obtained with respect to the detection limit, accuracy and precision. Also, decision limits were calculated for declaring non-conformance (>0.9%) with 95% reliability. In order to estimate the contribution of the different steps in the GMO analysis to the total variation variance components were estimated using REML (residual maximum likelihood method). From these components, relative standard deviations for repeatability and reproducibility (RSDr and RSDR) were calculated. The results showed that not only the PCR reaction but also the factors ‘DNA isolation’ and ‘PCR day’ are important factors for the total variance and should therefore be included in the in-house validation. It is proposed to use a statistical model to estimate these factors from a large dataset of initial validations so that for similar GMO methods in the future, only the PCR step needs to be validated. The resulting data are discussed in the light of agreed European criteria for qualified GMO detection methods. Electronic supplementary material The online version of this article (doi:10.1007/s00216-009-3315-6) contains supplementary material, which is available to authorized users.