Bt-toxin Cry1Ab as produced in MON810 and Bt11: some very basic questions

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1 Bt-toxin Cry1Ab as produced in MON810 and Bt11: some very basic questions Dr. Christoph Then Andreas Bauer-Panskus

2 About Testbiotech Testbiotech was founded in 2008 by a group of experts and registered as a nonprofit organisation to promote independent research and public debate on the impacts of biotechnology. Testbiotech conducts its own studies or commissions research projects from other institutions and uses the relevant findings to raise broader public awareness.

3 Risk reloaded... report risk reloaded dealing with basic concepts of risk assessment, and general problems in independent risk research: current concepts starting with substantial equivalence and familarity are not adequate conventional breeding and genetic engineering are substantially different

4 Some basic questions How much Bt toxin do genetically engineered MON810 maize plants actually produce? How about selectivity and efficacy of Bt toxins?

5 Products on the EU market for cultivation producing Cry1Ab MON810 (Monsanto), Bt maize not allowed in Germany, France, Austria u.a. Bt11 (Syngenta), Maize 1507 (Pioneer): authorisation in 2010? Withdrawn: Bt176 Stacked events around the corner...

6 How much Bt toxin do genetically engineered MON810 maize plants actually produce? No standardised method / test protocol is available developed by ring trials involving several independent laboratories Results of ELISA depends on specific protocol

7 How much Bt toxin do genetically engineered MON810 maize plants actually produce? Then&Lorch (2008)

8 How much Bt toxin do genetically engineered MON810 maize plants actually produce? Lorch&Then (2007)

9 Statement from EU Commission Recent studies indicate that there is both a high variation of toxin concentration between plants on a field as well as statistically significant differences between different locations in Germany, where the studies have been conducted. The reasons for such differences in the plants and in the locations as well as the range of variation are not yet identified and may lead to unpredicted interactions with the environment that could cause adverse effects. EU Commission, 2007, Draft decision. Concerning the placing on the market, in accordance with Directive 2001/18/EC of the European Parliament and of the Council, of a maize product (Zea mays L., line Bt11) genetically modified for resistance to certain lepidopteran pests and for tolerance to the herbicide glufosinate-ammonium.

10 How about selectivity and efficacy? Then (2009)

11 How about selectivity and efficacy? Crickmore (2005): "Nonetheless, convincing evidence now exists for the involvement of two proteins (... ) and a set of glycolipids as receptors of Bt toxins. Circumstancial evidence, based on binding studies, also exists for the involvement of many other membrane proteins. With so many potential binding sites, the question arises as to their relative importance."

12 How about selectivity and efficacy? Pigott und Ellar (2007) Even the general view that toxin monomers bind to midgut-receptors, oligomerize, and insert into the membrane to form lytic pores has recently been challenged.

13 How about selectivity and efficacy? Broderick (2006) For decades, the mechanism of insect killing has been assumed to be toxin-mediated lysis of the gut epithelial cells, which leads to starvation, or B.thuringiensis septicemia. Here, we report that B. thuringiensis does not kill larvae of the gypsy moth in the absence of indigenous midgut bacteria. Elimination of the gut microbial community by oral administration of antibiotics abolished B. thuringiensis insecticidal activity, and reestablishment of an Enterobacter sp. that normally resides in the midgut microbial community restored B.thuringiensis-mediated killing.

14 Case study: honey bees Co-factors and Bt-Toxin causing higher mortality in bees Kaatz, 2005

15 Effects on non target organisms: Time to reassess selectivity Some species affected besides Lepidoptera: Adalia bipunctata (Schmidt et al 2008), Chrysoperla carnea (Hilbeck et al, 1998 and 1999), Daphnia magna (Bøhn et al 2008), Trichopteran, (Lepidostoma liba, Rosi-Marshall et al 2007) Honey bees (Apis mellifera, Ramirez-Romero et al 2008) Snails (Kramarz 2007)

16 Effects on non target organisms: Time to reassess selectivity Cry-toxins and toxic effects relevant for mammals: Nematodes (mechanisms observed being relevant in mammals): Huffmann et al (2004) Cytocidal activity on human cancer cells: Ito et al (2004)

17 Conclusions Market authorisation of genetically engineered crops such as MON810 has to be put in question: Basic questions related to selectivity, efficacy of the Bt-toxin can not be answered. The actual concentration of the Bt-toxin in the plants under changing environmental conditions is not known. Thank you very much for your attention!