The effect of ensiling on PCR-based detection of genetically modified Bt maize

Hupfer, Christine; Mayer, J. B.; Hotzel, Helmut; Sachse, Konrad; Engel, Karl‐Heinz

doi:10.1007/s002170050498

Cited by 41 publications

(27 citation statements)

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“…This response suggests that DNA fragments decrease in size during fermentation as a result of endonucleotic enzyme activity. These results confirm recent observations (Hupfer et al 1999;Lutz et al 2006) that plant DNA is rapidly degraded to smaller fragments during the ensiling process and as a result likely loses functional properties.…”

Section: Resultssupporting

confidence: 92%

“…Some research showed that the ensiling of forages had no detectable effect on DNA fragmentation (Beever and Kemp 2000;Beever and Phipps 2001) and that DNA can be extracted from corn silages Chiter et al 2000). Other reports, however, found that only small fragments of the cry1A(b) gene could be detected in corn silage and that the presence of intact and functional genes after an extended period of ensiling was unlikely (Hupfer et al 1999;Lutz et al 2006;Wiedemann et al 2006). The Bt protein appears equally sensitive to degradation; the concentration of cry1A(b) protein in ensiled Bt corn was only 10% that of whole-plant corn or even undetectable (Fearing et al 1997).…”

Section: Mots Clé S: Maı¨s Transge´nique Ensilage Traitement Des Grmentioning

confidence: 99%

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Outcome of Bt transgenes and protein in corn silage, processed grains, and rumen content

Tremblay¹,

Laberge²,

Castonguay³

et al. 2008

Can. J. Anim. Sci.

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2008. Outcome of Bt transgenes and protein in corn silage, processed grains, and rumen content. Can. J. Anim. Sci. 88: 85Á95. The environmental impact of transgenic plants has been questioned due to the potential persistence of proteins encoded by transgenes and horizontal gene transfer from the plant to gut microbes. The outcome of the encoded Bt [cry1A(b)] protein and transgene fragments cry1A(b), bar, and bla) was monitored in silage and processed grains of two commercial Bt11 (NK N44-P4 Bt LL and NK N27-M3 Bt LL) and one Bt176 (Elite N09-K9 Bt) corn hybrids. The three Bt-corn hybrids with their non-Bt isolines were field-grown in four replicates. Seven 1.4-kg capacity mini-silos were prepared per plot and then opened after 1, 2, 4, 8, 16, 32, and 64 d. For each hybrid, two 500-kg plastic bag silos were also prepared, sampled after 30 and 198 d, and used in a feeding trial. In the mini-silos, the transgene fragments could no longer be amplified 32 d after ensiling. In the 500-kg plastic bag silos, the transgene fragments were still detectable in the three Bt hybrid silages 30 and 198 d after ensiling. At ensiling, the Bt protein concentration was 2.69, 4.11, and 0.83 mg g(1 DM for the Bt hybrids N44-P4, N27-M3, and N09-K9, respectively. After 64 d of fermentation in the mini-silos, the concentration was 4, 2, and 1% of the initial concentration, respectively, but was 16, 9, and 9% after 198 d in the 500-kg silos. After stringent processing treatments, transgene fragments, except the bla gene fragment, could still be amplified from corn grains. The Bt protein concentration in corn grain of the three Bt hybrids (initially 61, 239, and 21 ng g Á1 DM, respectively) decreased by 35, 74, and 67%, respectively, after micronization, by 92, 98, and 89% after extrusion, and by 100% after flaking. After 7 d of feeding Bt corn silage to six dairy cows, Bt protein increased in ruminal digesta with higher concentrations for Bt11 hybrids than the Bt176 hybrid; in all cases, however, concentrations were very low in forage digesta and below detection levels in rumen fluid.

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Section: Resultssupporting

confidence: 92%

Section: Mots Clé S: Maı¨s Transge´nique Ensilage Traitement Des Grmentioning

confidence: 99%

Outcome of Bt transgenes and protein in corn silage, processed grains, and rumen content

Tremblay¹,

Laberge²,

Castonguay³

et al. 2008

Can. J. Anim. Sci.

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“…Survival of DNA in silage and maize grains fed to sheep A PCR strategy previously used for the detection of a chromosomally integrated transgene, cry1A(b ), in foods derived from GM maize and in GM maize silage (Hupfer et al 1999) was employed to investigate the stability of the transgene in GM maize silage and grain fed to sheep. Before starting the feeding trials, tests were performed to determine whether PCR-amplifiable DNA could be isolated from maize tissues in the presence of rumen fluid.…”

Section: Resultsmentioning

confidence: 99%

“…1. PCR amplification of a 226-bp maize-specific region of the invertase gene ivr1 was performed using primers ivr1-F and ivr-R, described by Ehlers et al (Hupfer et al 1999). Amplification of a 214-bp fragment of pCRY6 was carried out using T7 universal primer and the previously described Cry04 primer (Hupfer et al 1998).…”

Section: Oligonucleotide Primers and Polymerase Chain Reactionmentioning

confidence: 99%

Fate of genetically modified maize DNA in the oral cavity and rumen of sheep

2003

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The polymerase chain reaction (PCR) technique was used to investigate the fate of a transgene in the rumen of sheep fed silage and maize grains from an insect-resistant maize line. A 1914-bp DNA fragment containing the entire coding region of the synthetic cryIA(b ) gene was still amplifiable from rumen fluid sampled 5 h after feeding maize grains. The same target sequence, however, could not be amplified from rumen fluid sampled from sheep fed silage prepared from the genetically modified maize line. PCR amplification of a shorter (211-bp), yet still highly specific, target sequence was possible with rumen fluid sampled up to 3 and 24 h after feeding silage and maize grains, respectively. These findings indicate that intact transgenes from silage are unlikely to survive significantly in the rumen since a DNA sequence 211-bp long is very unlikely to transmit genetic information. By contrast, DNA in maize grains persists for a significant time and may, therefore, provide a source of transforming DNA in the rumen. In addition, we have examined the biological activity of plasmid DNA that had previously been exposed to the ovine oral cavity. Plasmid extracted from saliva sampled after incubation for 8 min was still capable of transforming competent Escherichia coli to kanamycin resistance, implying that DNA released from the diet within the mouth may retain sufficient biological activity for the transformation of competent oral bacteria.

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“…In a recent review, Jonas et al (2001) noted that studies conducted by Hupfer et al (1999) indicate that, while the origin of the silage made from GM crops could be confirmed, it showed that the ensiling process resulted in major fragmentation of the transgenic DNA (tDNA) and that the presence of intact, functional genes after an extended time of ensiling was highly unlikely.…”

Section: Conservation and Processing Of Gm Feedsmentioning

confidence: 99%

Environmental Impact of Genetically Modified Crops

Ferry¹,

Gatehouse²

2009

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This book, containing 20 chapters, addresses the major concerns of scientists, policy makers, environmental lobby groups and the general public regarding the controversial issue on environmental impact (e.g. on soil and water ecology and nontarget organisms) of transgenic crops, from an editorially neutral standpoint. While the main focus is on environmental impact, food safety issues for both humans and animals are also considered. Some chapters discuss issues on resistance management. The book concludes with a discussion on the future of agricultural biotechnology in the context of sustainability, natural resource management and future global population and food supply.

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The effect of ensiling on PCR-based detection of genetically modified Bt maize

Cited by 41 publications

References 1 publication

Outcome of Bt transgenes and protein in corn silage, processed grains, and rumen content

Outcome of Bt transgenes and protein in corn silage, processed grains, and rumen content

Fate of genetically modified maize DNA in the oral cavity and rumen of sheep

Environmental Impact of Genetically Modified Crops

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