Quantitative detection of Secale cereale by real-time PCR amplification

Fate of transgenic DNA and evaluation of metabolic effects in goats fed genetically modified soybean and in their offsprings

The presence of DNA fragments in blood and milk from goats fed conventional (control) or Roundup Ready® soybean meal solvent extracted (s.e.; treated) was investigated by using a polymerase chain reaction approach. The same investigation was carried out on blood, skeletal muscle and organs from kids of both groups fed only dams' milk until weaning. Moreover, the possible effects on cell metabolism were evaluated by determination of several specific enzymes in serum, heart, skeletal muscle, liver and kidney. Fragments of the multicopy chloroplast (trnL) gene were found in blood and milk samples from goats of both groups. In kids, the chloroplast fragments were found in samples of both groups. In samples, which proved positive for the presence of chloroplast DNA, fragments of the specific soybean single copy gene (lectin) were detected in several blood and milk samples. The same fragment was also found in control and treated groups of kids. Transgenic fragments were not found in those samples, which were found positive for chloroplast fragments of control groups of either goats or kids. On the contrary, in blood and milk of treated goats, fragments both of the 35S promoter and the CP4 epsps gene were detected. These fragments were also found in treated kids with a significant detection of the 35S promoter in liver, kidney and blood, and of the CP4 epsps gene fragment in liver, kidney, heart and muscle. A significant increase in lactic dehydrogenase, mainly concerning the lactic dehydrogenase-1 isoenzyme was found in heart, skeletal muscle and kidney of treated kids, thus suggesting a change in the local production of the enzyme. Finally, no significant differences were detected concerning kid body and organ weight.

Detection of plant species-specific dna (barley and soybean) in blood, muscle tissue, organs and gastrointestinal contents of rabbit

The aim of this study was to detect plant DNA sequences from low copy number genes of barley grain and soybean meal, the latter being subjected to solvent extraction process, in blood, liver, kidney, spleen, muscle tissue and digesta (duodenum, caecum and faeces from rectal ampulla) of rabbits. For fattening, Hyla rabbits (20 males and 20 females) were fed a diet including barley grain (15%) and soybean meal (12%). Animals were slaughtered at 74 d of age (2 ± 0.2 kg live weight) and samples collected from each animal. The quality of each DNA sample was verified using the UNIV P/Q primers used to amplify a mammalian specifi c portion of mtDNA 16S rRNA gene. The presence of plant DNA was subsequently ascertained on the same DNA samples, as well as on barley and soybean (control). Two classes of plant DNA sequences were monitored via real-time PCR, using SYBR® Green I Dye: a high copy number chloroplast gene (trnl) and a low copy number specific for barley (metal-dependent hydrolase-like protein) and soybean (lectin) genes. Melting curve analysis was used to identify the PCR products. The chloroplast fragment detection frequency was higher (P<0.01) in muscle (90%), liver (80%), kidney (80%) and spleen (80%) than in blood (40%) and digesta samples. In the latter, chloroplast DNA was found in 40 and 30% of duodenum and caecum contents respectively, and in 30% of faeces. The specificity of the amplicons obtained was checked by sequencing and annotation. In the samples positive for chloroplast fragments, the frequency of detection of barley specific sequence was higher (P<0.01) in liver (62.5%), kidney (62.5%), spleen (62.5%) and digesta (100%) than in blood (25%) and muscle (22.2%) samples. The soybean lectin gene was not detected in animal samples, although it was seen in plant samples. Results confirm that, except for gastrointestinal tract (GIT), plant single copy genes are more difficult to identify in animal samples.

Microfluorimeter with disposable polymer chip for detection of coeliac disease toxic gliadin

Coeliac disease is an inflammatory disease of the upper small intestine and results from gluten ingestion in genetically susceptible individuals, and is the only life-long nutrient-induced enteropathy. The only treatment is a strict gluten-free diet and the longer the individual fails to adhere to this diet, the greater the chance of developing malnutrition and other complications. The existence of reliable gluten free food is crucial to the well-being of the population. Here we report on a microfluorimeter device for the in situ detection of gliadin in foodstuffs, which could be used for a rapid control of raw materials in food processing, as well as for process control of gliadin contamination. The microfluorimeter is based on a reflector that is used inside a microfluidic chip, exploiting various strategically placed reflective or totally metallised mirrors for efficient collection of the fluorescent light emitted in a large solid angle. The chip is capable of executing five assays in parallel and has been demonstrated to possess detection sensitivity applicable to fluoroimmunoassays. Various immunoassay formats exploiting fluorescence detection, using enzyme/fluorophore labels were developed and compared in terms of sensitivity, ease of assay, assay time and compatibility with buffer used to extract gliadin from raw and cooked foodstuffs, with the best performance observed with an indirect competition assay using a fluorophore-labelled anti-mouse antibody. This assay was exploited within the microfluorimeter device, and a very low detection limit of 4.1 ng/mL was obtained. The system was observed to be highly reproducible, with an RSD of 5.9%, for a concentration of 50 ng/mL of gliadin applied to each of the five channels of the microfluorimeter. Biofunctionalised disposable strips incorporated into the microfluorimeter were subjected to accelerated Arrhenius thermal stability studies and it was demonstrated that strips pre-coated with gliadin could be stored for approximately 2 years at 4 degrees C, with no discernable loss in sensitivity or detectability of the assay. Finally, the microfluorimeter was applied to the analysis of commercial gluten-free food samples, and an excellent correlation with routine ELISA measurements was obtained. The developed microfluorimeter should find widespread application for on-site execution of fluoroimmunoassays.

Real-time PCR for quantitative detection of bovine tissues in food and feed

A real-time PCR approach with the SYBR Green detection system has been developed for the quantitative detection of bovine tissues in food and feedstuffs. The method combines the use of bovine-specific primers, which amplify an 84-bp fragment of the mitochondrial 12S rRNA gene, and universal primers, which amplify a 140-bp fragment of the nuclear 18S rRNA gene from eukaryotic DNA. The 18S rRNA primers are used as endogenous controls for the total content of PCR-amplifiable DNA in the sample. The specificity of the primers was tested against 18 animal species, including mammals, birds, and fish, as well as 6 plant species. Analysis of experimental bovine tissues-oats mixtures demonstrated the suitability of the assay for the detection of bovine DNA in mixtures containing as low as 0.1% of bovine tissues. The performance of the method is not affected by severe heat treatment (up to 133 degrees C for 20 min at 300 kPa). The reported PCR assay could be very useful for detecting bovine-derived ingredients in raw and heat-treated food and feedstuffs.

Genetically modified soya bean in rabbit feeding: detection of DNA fragments and evaluation of metabolic effects by enzymatic analysis

The presence of DNA fragments in tissues from rabbits given genetically modified (GM) soya-bean meal (solvent extracted) was investigated by using the polymerase chain reaction (PCR) approach. Moreover, the possible effects on cell metabolism were evaluated by determination of several specific enzymes in serum, heart, skeletal muscle, liver and kidney. The chloroplast sequence for tRNA Leu by using the Clor1/Clor2 primers designed on chloroplast trnL sequence was clearly detected. On the contrary, two couples of species specific primers for conventional (Le1-5/Le 1-3 which amplifies the soya bean lectin gene) and genetically modified (35S1/35S2 which amplifies the 35S CMV promoter that is present in the genomic structure of GM soya bean) soya bean were not found in all samples. No differences in enzyme levels were detected in serum, but a significant increase of lactic dehydrogenase, mainly concerning the LDH1 isoenzyme was found in particular in kidney and heart but not in the muscle, thus suggesting a potential alteration in the local production of the enzyme. Finally, no significant differences were detected concerning body weight, fresh organ weights and no sexual differences were detected.