Isogenic Maize Research Articles

High-Throughput Sequence-Based Analysis of the Intestinal Microbiota of Weanling Pigs Fed Genetically Modified MON810 Maize Expressing Bacillus thuringiensis Cry1Ab (Bt Maize) for 31 Days

The objective of this study was to investigate if feeding genetically modified (GM) MON810 maize expressing the Bacillus thuringiensis insecticidal protein (Bt maize) had any effects on the porcine intestinal microbiota. Eighteen pigs were weaned at ~28 days and, following a 6-day acclimatization period, were assigned to diets containing either GM (Bt MON810) maize or non-GM isogenic parent line maize for 31 days (n = 9/treatment). Effects on the porcine intestinal microbiota were assessed through culture-dependent and -independent approaches. Fecal, cecal, and ileal counts of total anaerobes, Enterobacteriaceae, and Lactobacillus were not significantly different between pigs fed the isogenic or Bt maize-based diets. Furthermore, high-throughput 16S rRNA gene sequencing revealed few differences in the compositions of the cecal microbiotas. The only differences were that pigs fed the Bt maize diet had higher cecal abundance of Enterococcaceae (0.06 versus 0%; P < 0.05), Erysipelotrichaceae (1.28 versus 1.17%; P < 0.05), and Bifidobacterium (0.04 versus 0%; P < 0.05) and lower abundance of Blautia (0.23 versus 0.40%; P < 0.05) than pigs fed the isogenic maize diet. A lower enzyme-resistant starch content in the Bt maize, which is most likely a result of normal variation and not due to the genetic modification, may account for some of the differences observed within the cecal microbiotas. These results indicate that Bt maize is well tolerated by the porcine intestinal microbiota and provide additional data for safety assessment of Bt maize. Furthermore, these data can potentially be extrapolated to humans, considering the suitability of pigs as a human model.

Effects of an active immunization on the immune response of laying Japanese quail (Coturnix coturnix japonica) fed with or without genetically modified Bacillus thuringiensis-maize

Potentially adverse effects of diets containing transgenic plants are a concern for many consumers, particularly in Europe. For Bacillus thuringiensis-maize, several studies in livestock and poultry showed that the zootechnical data provide no indication for such adverse effects. These studies were all done in homeostatic situations; it remained open whether a deflection of the regulatory physiological systems might yield divergent dynamic responses in B. thuringiensis-maize-fed animals. We therefore tested the effect of an active immunization using BSA as antigen in a feeding regimen with or without B. thuringiensis-maize using quail as a model organism. Newly hatched Japanese quail were randomly allocated to 2 groups (n=120 per group) fed with diets containing either B. thuringiensis-maize or isogenic maize of the same cultivar. The diets did not differ in concentrations of the mycotoxins deoxynivalenol and zearalenone, which were both far below guidance values. After 16 wk on the experimental diets, one-half of each group was immunized against BSA. The remaining birds were injected with saline. Thirty-six hours after the injection, half of the BSA-injected subgroup (n=30) and half of the saline subgroup (n=30) from B. thuringiensis-maize- and isogenic-fed birds were killed and blood samples were collected and analyzed for serum zinc levels, indicative for acute phase response. For determining IgY-mediated immune responses, eggs were collected every other week for 6 wk after the injections from the remaining birds and total IgY concentrations and BSA-specific IgY titers were measured in egg yolk. The BSA injections did not elicit significant decreases of serum zinc concentrations. The serum zinc levels were significantly higher in B. thuringiensis-maize-fed quail. Expectedly, total IgY as well as BSA-specific IgY titers increased with time in the BSA-immunized quail. The response of both variables to the BSA injection did not differ between the feeding groups. Our results indicate that feeding of B. thuringiensis-maize does not impair the immune system of Japanese quail and thus gives no indication for respective concerns.

A review on comparative data concerning Fusarium mycotoxins in Bt maize and non-Bt isogenic maize

The European corn borer reportedly promotes the infection of maize by Fusarium spp. Stalk and ear rots caused by Fusarium spp. are often related to mycotoxin accumulation in maize kernels. As a result, food and animal feed from maize are more severely contaminated with Fusarium mycotoxins: e.g. fumonisins (FUM), deoxynivalenol (DON) and zearalenone (ZEA). Bt maize is primarily an important potential tool for insect pest protection, both in the European Union and in other countries. Bt maize carrying the Bt genes is highly resistant to European corn borer larval feeding due to Bt toxin (δ toxin) production. Effective measures to combat pests therefore often have a positive side-effect in that they also reduce mycotoxin levels. Comparative analysis was used to the evaluation of the studies dealing with the reduction of Fusarium mycotoxins in Bt maize. Nineteen out of 23 studies on Bt maize came to the conclusion that Bt maize is less contaminated with mycotoxins (FUM, DON, ZEA) than the conventional control variety in each case.

Rove beetle (Coleoptera: Staphylinidae) communities in transgenic Bt (MON810) and near isogenic maize

Field experiments were conducted to investigate the mechanism of the underlying patterns (abundance, species richness, diversity and similarity) of rove beetles in transgenic Bt (MON810) and in near isogenic maize stands in Hungary. During the three-year (2001–2003) survey, 1538 individuals and 21 species were sampled with pitfall traps. The Cry1Ab protein expressed by the MON810 maize hybrid did not influence the overall community structure. After grouping staphylinids into guilds we found no significant differences for non-aphidophagous predators and parasitoids, whereas there were significantly and marginally significantly higher abundances for predators with aphids in their diet in isogenic maize stands in 2002 and 2003 respectively. The abundance of the prey Rhopalosiphum padi (L.) showed a high fluctuation between stands and years and was numerically higher only in isogenic stands in the second half of the maize-growing season. The abundance of predatory guilds including aphids in their diet did not correlate with the total annual number of R. padi in the same year, but there was a linear correlation in successive years.

Effect of Bt-176 maize pollen on first instar larvae of the Peacock butterfly (Inachis io) (Lepidoptera; Nymphalidae)

More than 10 years after registration of the first Bt maize cultivar in Europe, there still exists a remarkable lack of data on effects on Lepidoptera which would be necessary for a complete and comprehensive environmental risk assessment. So far only very few European butterfly species have been tested in this aspect. In our study the effect of transgenic Bacillus thuringiensis (Bt) maize pollen (event Bt-176) on the development and survival of neonate larvae of the Peacock butterfly, Inachis io (L.) was for the first time shown. The results of our study suggest that the Peacock butterfly may serve as a model organism for assessing potential side effects of new developed transgenic Bt crops on non-target butterflies in a GMO environmental risk assessment. The study was done under laboratory conditions by exposing larvae of the Peacock butterfly to various pollen doses of transgenic maize event Bt-176 (cv. PACTOL CB) or the conventional isogenic maize (cv. PACTOL) using a no-choice test. Larvae feeding for 48 h on nettle plants (Urtica dioica) that were contaminated with higher pollen concentrations from Bt-176 maize (205 and 388 applied pollen.cm⁻²) suffered a significantly higher mortality rate (68 and 85% respectively) compared to larvae feeding on leaves with no pollen (11%), or feeding on leaves with pollen from conventional maize (6 to 25%). At lower Bt maize pollen doses (23-104 applied pollen.cm⁻²),mortality ranged from 11-25% and there were no apparent differences among treatments. The corresponding LC₅₀-and LC₉₀-values for neonate larvae of the Peacock butterfly were 187 and 448 applied pollen grains.cm⁻² of Bt-176, respectively.Weight of larvae surviving consumption of Bt-176 maize pollen declined between 10 and 81% with increased pollen doses (r = -0.95). The highest weight reduction (81%) corresponded to the highest pollen concentration (388 pollen grains applied.cm⁻²). Ingestion of pollen from the conventional maize hybrid did not have negative effects on larval weight gain or survival rate.

Cry1Ab toxin production of MON 810 transgenic maize

Levels of Cry1Ab toxin were detected in genetically modified maize of genetic event MON 810 against near isogenic maize as negative control by two commercial immunoassays. The immunoassays were characterized for their cross-reactivity (CR) between Cry1Ab protoxin and activated toxin, and were compared with each other for toxin detection in a reference plant sample. Cry1Ab toxin levels, corrected for active toxin content using the CR values obtained, were monitored in maize DK-440 BTY through the entire vegetation period. The toxin concentration was found to show a rapid rise in the leaves to 17.15 +/- 1.66 microg/g by the end of the fifth week of cultivation, followed by a gradual decline to 9.61 +/- 2.07 microg/g by the 16th week and a slight increase again to 13.51 +/- 1.96 microg/g during the last 2 weeks due to partial desiccation. Similar but lesser fluctuation of toxin levels was seen in the roots between 5.32 +/- 0.49 microg/g at the less differentiated V1 stage and 2.25 +/- 0.30 microg/g during plant development. In contrast, Cry1Ab toxin levels appeared to be stably 1.36 +/- 0.45, 4.98 +/- 0.31, 0.47 +/- 0.03, and 0.83 +/- 0.15 microg/g in the stem, anther wall, pollen, and grain, respectively. Toxin concentrations produced at the VT-R4 phenological stages under actual cultivation conditions were compared with each other in three different years within an 8-year period.

Demographic responses of Daphnia magna fed transgenic Bt-maize

The food/feed quality of a variety of genetically modified (GM) maize expressing Cry1Ab Bt-toxin was tested over the life-cycle of Daphnia magna, an arthropod commonly used as model organism in ecotoxicological studies. Demographic responses were compared between animals fed GM or unmodified (UM) near isogenic maize, with and without the addition of predator smell. Age-specific data on survival and birth rates were integrated and analysed using life tables and Leslie matrices. Survival, fecundity and population growth rate (PGR) data generally disfavoured transgenic Bt-maize as feed for D. magna compared to animals fed the unmodified (UM) near isogenic line of maize. Decomposition of age-specific effects revealed that the most important contributions to a reduced PGR in the GM-fed group came from both fecundity and survival differences early in life. We conclude that juvenile and young adult stages are the most sensitive experimental units and should be prioritized in future research. These stages are often omitted in toxicological/ecotoxicological studies and in feeding trials.

Evaluating Precision and Accuracy When Quantifying Different Endogenous Control Reference Genes in Maize Using Real-Time PCR

The agricultural biotechnology industry routinely utilizes real-time quantitative PCR (RT-qPCR) for the detection of biotechnology-derived traits in plant material, particularly for meeting the requirements of legislative mandates that rely upon the trace detection of DNA. Quantification via real-time RT-qPCR in plant species involves the measurement of the copy number of a taxon-specific, endogenous control gene exposed to the same manipulations as the target gene prior to amplification. The International Organization for Standardization (ISO 21570:2005) specifies that the copy number of an endogenous reference gene be used for normalizing the concentration (expressed as a % w/w) of a trait-specific target gene when using RT-qPCR. For this purpose, the copy number of a constitutively expressed endogenous reference gene in the same sample is routinely monitored. Real-time qPCR was employed to evaluate the predictability and performance of commonly used endogenous control genes (starch synthase, SSIIb-2, SSIIb-3; alcohol dehydrogenase, ADH; high-mobility group, HMG; zein; and invertase, IVR) used to detect biotechnology-derived traits in maize. The data revealed relatively accurate and precise amplification efficiencies when isogenic maize was compared to certified reference standards, but highly variable results when 23 nonisogenic maize cultivars were compared to an IRMM Bt-11 reference standard. Identifying the most suitable endogenous control gene, one that amplifies consistently and predictably across different maize cultivars, and implementing this as an internationally recognized standard would contribute toward harmonized testing of biotechnology-derived traits in maize.

An evaluation of methods for assessing the impacts of Bt‐maize MON810 cultivation and pyrethroid insecticide use on Auchenorrhyncha (planthoppers and leafhoppers)

Abstract1 Auchenorrhyncha (Planthoppers and Leafhoppers) are not only pests of many crops, but they are also nontarget organisms with respect to Bt‐protein expressing genetically modified plants. As herbivorous arthropods, planthoppers and leafhoppers ingest Cry proteins depending on their feeding behaviour. Consequently, they are directly exposed to these entomotoxic proteins and can also serve as a source of Cry protein exposure to predatory arthropods. Therefore, it is reasonable to use Auchenorrhyncha in the risk assessment of genetically modified crops.2 During a 2‐year field study, we evaluated four different methods in terms of their feasibility to assess the impacts of plant‐incorporated protectants from Bt‐maize and of insecticide use on this group of arthropods. Visual assessment of plants, sweep netting, yellow traps and custom made sticky traps were utilized in field plots of Bt‐maize MON810, untreated near‐isogenic maize and insecticide‐treated near‐isogenic maize and were compared with respect to their capability to reflect the diversity and abundance of Auchenorrhyncha species.3 Zyginidia scutellaris (Herrich‐Schäffer) (Cicadomorpha: Cicadellidae) represented more than 94% of all captured individuals in both years. The analysis of Z. scutellaris data showed no consistent differences between Bt‐maize MON810 and the untreated near isogenic hybrid, demonstrating no negative impact of MON810 on this species. Insecticide treatment, on the other hand, was not equivalent to the isogenic maize in terms of Z. scutellaris densities. Based on the collected data and on practical considerations, we recommend the combined use of transect‐wise sweep netting and sticky traps for the sampling of Auchenorrhyncha in maize.

Fate of genetically modified maize and conventional rapeseed, and endozoochory in wild boar ( Sus scrofa)

Feeding experiments were carried out to investigate the digestive fate of transgenic DNA and novel protein in wild boar applying polymerase chain reaction (PCR) and immunodiagnostic techniques. Furthermore, the dispersal of viable maize and rapeseed (endozoochory) was studied. A diet containing conventional rapeseed, and either genetically modified (GM) maize expressing Cry1Ab protein (Bt176) or non-GM isogenic maize was offered. By conventional and quantitative PCR both chloroplast-specific plant DNA ( rubisco) and cry1Ab gene fragments were detected only in gastrointestinal content. Using an enzyme-linked immunosorbent assay (ELISA) positive signals of immunoactive Cry1Ab protein were detected in digesta samples. Analysis of endozoochory showed that excreted maize seeds retain their germination capacity only in extremely rare cases and no intact rapeseed was found in faeces. A possible dispersal of viable seeds by wild boars is highly unlikely.

Reduced Fitness of Daphnia magna Fed a Bt-Transgenic Maize Variety

Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects on survival, growth, and reproduction of the water flea Daphnia magna, a crustacean arthropod commonly used as a model organism in ecotoxicological studies. In three repeated experiments, D. magna were fed 100% ground maize in suspension, using either GM or isogenic unmodified (UM) maize. D. magna fed GM-maize showed a significantly reduced fitness performance: The mortality was higher, a lower proportion of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed UM isogenic maize. We conclude that the tested variety of Bt-maize and its UM counterpart do not have the same quality as food sources for this widely used model organism. The combination of a reduced fitness performance combined with earlier onset of reproduction of D. magna fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GM-maize.

Effect of Transgenic Maize Mon 810 on Selected Non-Target Organisms: The Bird Cherry-Oat Aphid (Rhopalosiphum padi L.) and its Predator - Green Lacewing (Chrysoperla carnea Steph.)

Effect of Transgenic Maize Mon 810 on Selected Non-Target Organisms: The Bird Cherry-Oat Aphid (Rhopalosiphum padi L.) and its Predator - Green Lacewing (Chrysoperla carnea Steph.) The maize variety MON 810 resistant on lepidopteran pests is one of the most common and longest grown transgenic variety. It was modified to constantly produce in its tissues Cry1Ab protein derived from common bacteria Bacillus thuringensis. The Cry1Ab protein is lethally-toxic for European corn borer (Ostrinia nubilalis), significant maize pest. A study was carried out to evaluate the influence of MON 810 maize on development of two non-target species - the bird cherry-oat aphid (Rhopalosiphum padi L.) and its predator - green lacewing (Chrysoperla carnea Steph.). During comparison analysis there were no significant differences between transgenic maize vs. non-transgenic isogenic maize influence on non-target organisms.

High susceptibility of Bt maize to aphids enhances the performance of parasitoids of lepidopteran pests.

Concerns about possible undesired environmental effects of transgenic crops have prompted numerous evaluations of such crops. So-called Bt crops receive particular attention because they carry bacteria-derived genes coding for insecticidal proteins that might negatively affect non-target arthropods. Here we show a remarkable positive effect of Bt maize on the performance of the corn leaf aphid Rhopalosiphum maidis, which in turn enhanced the performance of parasitic wasps that feed on aphid honeydew. Within five out of six pairs that were evaluated, transgenic maize lines were significantly more susceptible to aphids than their near-isogenic equivalents, with the remaining pair being equally susceptible. The aphids feed from the phloem sieve element content and analyses of this sap in selected maize lines revealed marginally, but significantly higher amino acid levels in Bt maize, which might partially explain the observed increased aphid performance. Larger colony densities of aphids on Bt plants resulted in an increased production of honeydew that can be used as food by beneficial insects. Indeed, Cotesia marginiventris, a parasitoid of lepidopteran pests, lived longer and parasitized more pest caterpillars in the presence of aphid-infested Bt maize than in the presence of aphid-infested isogenic maize. Hence, depending on aphid pest thresholds, the observed increased susceptibility of Bt maize to aphids may be either a welcome or an undesirable side effect.

Activity density, diversity and seasonal dynamics of ground beetles (Coleoptera: Carabidae) in &lt;i&gt;Bt&lt;/i&gt;- (MON810) and in isogenic maize stands

To compare carabid assemblages from transgenic Bt- and isogenic maize in Hungary, we used pitfall traps in an experiment (30x30 m plots, arranged alternately in 6 replications), during the growing season of maize during 2001—2003. We captured altogether 44,103 individuals of 58 species. The most common species in our sampling were Calatlzus ambiguus, Doliclzus halensis, Harpalus distinguendus, H rufipes, Poecilus sericeus and Treclius quadristriatus. The same species dominated both in the Bt- and in the isogenic maize plots. Under our test conditions (plot size and 3 years of sampling), no significant differences were found either in the structural characteristics (number of individuals, number of species and diversity), activity density or seasonal activity patterns ofthe dominant species.

Arthropods on Maize Ears for Detecting Impacts ofBtMaize on Nontarget Organisms

A 3-yr study (2001–2003) was conducted to determine if the cultivation of Bt maize (Mon810, cultivar Novelis), compared with an isogenic maize line (cultivar Nobilis) with and without an insecticide treatment, has unintended effects on nontarget organisms of the arthropod community in maize fields. Furthermore, suitable monitoring organisms and appropriate methods should be selected. Maize ear samples were taken in Bt maize, an isogenic maize variety, and an isogenic maize variety with insecticide treatment. The community of arthropods was monitored and evaluated. In the first year of the study, the abundance of the mycetophagous/saprophagous beetle species Cortinicara gibbosa was significantly higher in Bt maize than in the isogenic control. These differences in arthropod communities between Bt maize and the isogenic control were not reproducible in the following years. No other significant differences in arthropod communities between Bt maize and the control were observed. Several significant differences between the insecticide-treated plots and the other treatments were detected. The abundance of the aphid Rhopalosiphum padi was significantly higher in the insecticide-treated plots than in the Bt maize or control plots over all 3 yr. The same was observed for the ladybird Coccinella septempunctata in 2003. Thrips populations were influenced negatively by the application of insecticide in 2002 and 2003. Sampling of maize ears is a suitable method in detecting changes of arthropod abundance on the community level.

Effect of Bt-maize on epigeic spiders (Araneae) and harvestmen (Opiliones)

The effect of two strategies, used to control &lt;i&gt;Ostrinia nubialis&lt;/i&gt;, on the abundance and diversity of epigeic spiders and harvestmen in maize was monitored. The two strategies were (1) transgenic insect-resistant maize, and (2) biological control by &lt;i&gt;Trichogramma&lt;/i&gt; wasps on an isogenic maize hybrid. They were compared with a conventional system (isogenic maize hybrid), which was taken as the control. The investigation was performed at two localities (Ivanovice na Hané and Prague) in the Czech Republic from 2002 to 2004. Spiders (Araneae) and harvestmen (Opiliones) were collected by means of pitfall traps. We found that the annual abundance and diversity of arachnids on plots with the two strategies were not significantly different from a conventional system. The overall abundance of spiders decreased over three years in all systems. There was no difference in the family and guild (hunters versus web-builders) composition between strategies and the conventional system. A displacement of linyphiid spiders with lycosids on all plots over time was observed. This change is attributed to the existence of a sparse weed cover of maize fields as a result of consecutive monocultural planting.

Foliage-dwelling arthropods in Bt-transgenic and isogenic maize: a comparison through spider web analysis

Theridion impressum is one of the dominant foliage dwelling spider species of maize fields in Hungary. Spider webs were collected from Bt and isogenic maize plots in three successive years. Captured insects in the web were identified. The most frequent prey items were aphids, plant hoppers and beetles. Although the number of captured insects in web samples from isogenic maize was slightly higher than those from Bt maize in the case of almost each insect order, except for two samples (Sternorrhyncha, 2001; Neuroptera, 2002), the differences between Bt and isogenic samples were not significant.

Transgenic Bt maize and Rhopalosiphum padi (Hom., Aphididae) performance

Abstract. 1. The population abundance and age structure of Rhopalosiphum padi, one of the most common maize aphid species, on transgenic Bt (expressing the Cry1Ab protein) and non‐Bt isogenic maize was studied in commercial plots during three crop seasons.2. A higher density of aphids, particularly alates and young nymphs, occurred in Bt plots at very young maize development stages, corresponding to the settlement period, in the 3 years studied. Possible causes are discussed. After this period, there were no differences between Bt and non‐Bt maize.3. Mortality, development, and reproduction of the offspring of alate forms of R. padi and the offspring of different generations of apterous forms fed with Bt maize were evaluated in the laboratory under controlled conditions.4. The developmental and pre‐reproductive times of the offspring of the first generation of alatae were shorter and the intrinsic rate of natural increase (rm) higher when aphids fed on Bt maize. The opposite occurs with the offspring of the first generation of apterous mothers, which have lower nymphal and adult mortality, shorter developmental and pre‐reproductive times, a higher effective fecundity rate, and greater rm, when fed on non‐Bt maize. The differences in aphid development on the two cultivars may be linked to changes in host‐plant quality due to pleiotropic effects of the genetic modification.5. No differences on aphid mortality, developmental and pre‐reproductive times, fecundity, and rm were found between the offspring of apterous aphids maintained on Bt or non‐Bt maize for several generations.

Amino acid digestibility and nitrogen utilization of high oil, high lysine, and waxy maize fed to growing pigs

Two experiments were conducted to determine the amino acid (AA) digestibility and nitrogen (N) utilization of three maize hybrids, i.e. high oil (HO), waxy (WX), and high lysine (HL) as compared to isogenic high oil (IHO), isogenic waxy (IWX), and a yellow dent (YD1) maize variety near-isogenic to HL. One yellow dent maize of unrelated genetics (YD2) was included as an additional control and to serve as a common treatment for cross-square comparison. In exp. 1, four castrates (initial BW: 52.8±1.7 kg) were equipped with T-cannulas in the distal ileum and used in two consecutive 4×4 Latin squares to determine AA digestibility. In exp. 2, eight castrates (initial BW: 19.11±0.49 kg) were arranged in two 4×4 Latin squares and used in a N balance experiment. Diets consisted of 966.2 g test maize/kg and 33.8 g vitamins, minerals, and salt/kg. In exp.1, apparent ileal digestibility coefficients (CAID) for HO and WX were not different ( P>0.05) compared to their respective isogenic maize or YD2. High lysine maize had lower ( P<0.05) CAID for isoleucine, leucine, methionine, phenylalanine, threonine, and valine when compared to YD1, its near-isogenic maize, and lower ( P<0.05) CAID for isoleucine, leucine, and phenylalanine when compared to YD2. Mean CAID for HO, WX, HL, and YD2 were 0.65±0.05, 0.70±0.05, 0.53±0.05, and 0.60±0.03, respectively. True ileal digestibility coefficients (CTID) for the indispensable AA did not differ when HO and WX maize were compared to their respective isogenic maize, but HL maize had lower ( P<0.05) CTID for the majority of indispensable AA except for arginine and histidine than YD1. Mean CTID for HO, WX, HL, and YD2 were 0.78±0.04, 0.84±0.04, 0.67±0.04, and 0.77±0.03, respectively. Nitrogen retained, urinary N, fecal N, N digestibility, and N utilization for HO, WX, and HL were not different ( P>0.05) compared to their genetically similar maize. Nitrogen absorbed and DM digestibility were higher ( P<0.05) for HO than for IHO. Nitrogen digestibility was similar ( P>0.05) for WX compared to YD 2 and greater ( P>0.05) for HO and HL compared to YD 2. In conclusion, AA CAID and CTID, were similar for HO and WX maize compared to their isogenic maize, however, AA CAID and CTID for HL maize was lower than its near-isogenic maize. Nitrogen utilization for HO, WX, and HL were similar to that of their respective genetically similar maize.

Editorial. The human side of GMO biosafety research

As you will have noticed from this issue of EBR, our cover photo contest was a success. To our surprise, we had several excellent entries that are quite different from the usual journal cover photo, since rather than presenting results, they show people working in GMO biosafety. Those of us involved in selecting the cover thought that some of these human interest photos would be worth publishing. One of the issues in the area of commercial use of transgenic plants expressing a Bt endotoxin gene is the potential for unintended effects on non-target insects. Figure 1, which was submitted by Detlef Bartsch (Berlin, Germany), shows three members of his team (Andreas Toschki, Markus Tepner, and Rene Mause) setting up pitfall traps and cages for catching soil-inhabiting arthropods, in a field study of the potential impact of Bt maize on non-target insects. The experiment consists of several 0.5 ha plots (six replications each) with three treatments: Bt-maize (expressing a Cry1Ab gene), isogenic maize sprayed with chemical insecticides, and isogenic maize without insecticides as a control. The aim is to make a complete inventory of arthropods living in the different plots over a three year period. If differences in species abundance between the treatments are observed, more in-depth studies with single species or species combinations may follow. One final goal is to identify keystone species for long-term monitoring of environmental effects. Meanwhile, Detlef Bartsch is now working in governmental regulation, and has handed over the project to Martina Ross-Nickoll and Achim Gathmann at the University of Aachen.