“…Nonetheless, they cannot simply be extrapolated to describe the potential ecological impacts of Cry proteins in the field, but have to be complemented with experiments under ecologically more realistic conditions (Lang et al 2007).…”
Section: Discussionmentioning
confidence: 99%
“…(Mendelsohn et al 2003;Andow and Hilbeck 2004). While this approach to risk assessment has attracted criticism with regard to the applied protocols stemming largely from the ecotoxicity testing schemes of chemicals (Andow and Hilbeck 2004;Andow et al 2006;Lang et al 2007), this type of testing currently still constitutes the main part of nontarget testing in transgenic plants. Therefore, we aimed at improving the existing protocols by using activated toxins, which is what transgenic plants are supposed to produce, and larvae of nontarget organisms instead of adults, as those are supposed to be more susceptible.…”
Insect-active Bacillus thuringiensis (Bt) proteins are expressed by several transgenic crop plants to control certain pests, but nontarget organisms such as ladybirds also can be exposed to these proteins in the field. We developed an improved ecotoxicity testing protocol and conducted feeding trials in a laboratory setting to test for possible adverse effects of different concentrations of microbially produced trypsin-activated Cry1Ab and Cry3Bb toxins on the coccinellid Adalia bipunctata. Larval/pupal mortality, development time, and overall body mass accumulation were recorded. Even at the lowest concentration (5 lg/ml), A. bipunctata larvae fed with the lepidopteran-active Cry1Ab toxin exhibited significantly higher mortality than the control group. In experiments with the coleopteran-active Cry3Bb, only a concentration of 25 lg/ml resulted in a marginally significantly higher mortality compared to the control. Both experiments revealed a slight decline in mortality at the highest concentration of 50 lg/ml, though this was statistically significant only in the Cry1Ab treatment. No differences were detected for development time and body mass of newly emerged adults. Dilutions of the expression vector pBD10-used as a control to exclude effects of the toxin production method-at concentrations between 10 and 100 lg/ml revealed no significant effects on either of the studied parameters. This suggests that the increased mortality of larvae in the toxin feeding trials was caused directly by the activated Bt toxins and raises questions regarding their commonly postulated specificity and their mode of action in A. bipunctata. Implications of the reported results for ladybird populations and their biological pest control functions in transgenic crop ecosystems are discussed.
“…Nonetheless, they cannot simply be extrapolated to describe the potential ecological impacts of Cry proteins in the field, but have to be complemented with experiments under ecologically more realistic conditions (Lang et al 2007).…”
Section: Discussionmentioning
confidence: 99%
“…(Mendelsohn et al 2003;Andow and Hilbeck 2004). While this approach to risk assessment has attracted criticism with regard to the applied protocols stemming largely from the ecotoxicity testing schemes of chemicals (Andow and Hilbeck 2004;Andow et al 2006;Lang et al 2007), this type of testing currently still constitutes the main part of nontarget testing in transgenic plants. Therefore, we aimed at improving the existing protocols by using activated toxins, which is what transgenic plants are supposed to produce, and larvae of nontarget organisms instead of adults, as those are supposed to be more susceptible.…”
Insect-active Bacillus thuringiensis (Bt) proteins are expressed by several transgenic crop plants to control certain pests, but nontarget organisms such as ladybirds also can be exposed to these proteins in the field. We developed an improved ecotoxicity testing protocol and conducted feeding trials in a laboratory setting to test for possible adverse effects of different concentrations of microbially produced trypsin-activated Cry1Ab and Cry3Bb toxins on the coccinellid Adalia bipunctata. Larval/pupal mortality, development time, and overall body mass accumulation were recorded. Even at the lowest concentration (5 lg/ml), A. bipunctata larvae fed with the lepidopteran-active Cry1Ab toxin exhibited significantly higher mortality than the control group. In experiments with the coleopteran-active Cry3Bb, only a concentration of 25 lg/ml resulted in a marginally significantly higher mortality compared to the control. Both experiments revealed a slight decline in mortality at the highest concentration of 50 lg/ml, though this was statistically significant only in the Cry1Ab treatment. No differences were detected for development time and body mass of newly emerged adults. Dilutions of the expression vector pBD10-used as a control to exclude effects of the toxin production method-at concentrations between 10 and 100 lg/ml revealed no significant effects on either of the studied parameters. This suggests that the increased mortality of larvae in the toxin feeding trials was caused directly by the activated Bt toxins and raises questions regarding their commonly postulated specificity and their mode of action in A. bipunctata. Implications of the reported results for ladybird populations and their biological pest control functions in transgenic crop ecosystems are discussed.
“…3), thereby accounting for differences in environmental effects of the same GMO in different regions, e.g. due to large-scale land-use changes [20] or because of interactions with GM plants that are already cultivated in a specific region [3]. This may be achieved by modifying the according to individual conservation priorities of EU Member States resulting in a regionally adapted damage threshold (the LoC regional ).Fig.…”
BackgroundThe European Food Safety Authority (EFSA) has introduced a concept for the environmental risk assessment of genetically modified (GM) plants which foresees the definition of ecological threshold values defining acceptable adverse effects of the GM plant on the environment (Limits of Concern, LoC).MethodsWe analysed the LoC concept by scrutinising its feasibility with regard to important aspects of the environmental risk assessment. We then considered its relationship with protection goals, the comparative safety assessment and the stepwise testing approach. We finally discussed its usefulness for assessing long-term effects, effects on non-target organisms and species of conservation concern.ResultsThe LoC concept is a possible approach to introduce ecological thresholds into environmental risk assessment in order to evaluate environmental harm. However, the concept leaves many important aspects open. Thresholds for environmental harm for protection goals need spatial and temporal differentiation from LoCs used for ERA indicators. Regionalisation of LoCs must be provided for as biodiversity levels and protection goals vary across the EU. Further guidance is needed with respect to the consequences, in case LoCs are exceeded and a link needs to be established between environmentally relevant results from the comparative safety assessment and the LoC concept. LoCs for long-term effects have to be evaluated by long-term monitoring. LoCs for non-target organisms need to be discriminated according to the species and parameters assessed.ConclusionsThe overall LoC concept is considered useful if LoCs are further specified and differentiated. Although LoCs will finally be determined by political decisions, they should be based on scientific grounds in order to increase confidence in the conclusions on the safety of GM plants.
“…However, again, controversy exists over whether the evidence for 'reason for concern' should be experimental (i.e. new original data produced) or could be extrapolated from theory and experience in related fields of science [8,9,[56][57][58]. Secondly, whether or not an absence of a 'reason for concern' (i.e.…”
Section: Effect Determination -Doing the Testing And Generating The Datamentioning
confidence: 99%
“…Secondly, whether or not an absence of a 'reason for concern' (i.e. evidence) constitutes evidence for safety to the effect that no more testing at higher levels is required [12,58] is subject to debate. Here, we briefly outline the basic concept of our vision for hierarchical testing of GM plants depicted in Figure 3.…”
Section: Effect Determination -Doing the Testing And Generating The Datamentioning
Background and purpose: In Europe, the EU Directive 2001/18/EC lays out the main provisions of environmental risk assessment (ERA) of genetically modified (GM) organisms that are interpreted very differently by different stakeholders. The purpose of this paper is to: (a) describe the current implementation of ERA of GM plants in the EU and its scientific shortcomings, (b) present an improved ERA concept through the integration of a previously developed selection procedure for identification of non-target testing organisms into the ERA framework as laid out in the EU Directive 2001/18/EC and its supplement material (Commission Decision 2002/623/EC), (c) describe the activities to be carried out in each component of the ERA and (d) propose a hierarchical testing scheme. Lastly, we illustrate the outcomes for three different crop case examples. Main features: Implementation of the current ERA concept of GM crops in the EU is based on an interpretation of the EU regulations that focuses almost exclusively on the isolated bacteria-produced novel proteins with little consideration of the whole plant. Therefore, testing procedures for the effect assessment of GM plants on non-target organisms largely follow the ecotoxicological testing strategy developed for pesticides. This presumes that any potential adverse effect of the whole GM plant and the plant-produced novel compound can be extrapolated from testing of the isolated bacteriaproduced novel compound or can be detected in agronomic field trials. This has led to persisting scientific criticism. Results: Based on the EU ERA framework, we present an improved ERA concept that is system oriented with the GM plant at the centre and integrates a procedure for selection of testing organisms that do occur in the receiving environment. We also propose a hierarchical testing scheme from laboratory studies to field trials and we illustrate the outcomes for three different crop case examples. Conclusions and recommendations: Our proposed concept can alleviate a number of deficits identified in the current approach to ERA of GM plants. It allows the ERA to be tailored to the GM plant case and the receiving environment.
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