Toxicological Evaluation of Brassica napus Extract Containing Vanadium, Nutricultured in Jeju Water.

This study evaluated the mutagenicity and acute toxicity of the juice extract of nutricultured Brassica napus containing vanadium (BECV). The BECV was prepared by nutriculture for 7 days in Jeju water containing vanadium. The mutagenic effects of BECV were investigated using the bacterial reverse mutation test, chromosome aberration test, and micronucleus test. Based on the results of the mutagenicity test, we propose that BECV is not a mutagenicity-inducing agent. In the acute oral toxicity study, male and female Sprague-Dawley rats were administered a single limiting dose of 0.014, 0.14, or 1.4 µg BECV/kg body weight; the rats were then observed for 7 days. No acute lethal effect was observed at the maximal dose of 1.4 µg BECV/kg body weight. In the subacute study, male and female rats were administered once daily, by oral gavage, a dose of 0.028, 0.14, and 0.7 µg/kg body weight of BECV for 28 days. No significant toxicity was observed not only hematological, biochemical, and pathological parameters but also the body and organ weights when compared to controls. The level of BECV with no observed adverse effects in male and female rats was 0.7 µg/kg body weight (concentration of vanadium in BECV) in the subacute toxicity study.

Bt-toxin uptake by the non-target herbivore, Myzus persicae (Hemiptera: Aphididae), feeding on transgenic oilseed rape in laboratory conditions.

The potential non-target effects of genetically modified crops are some of the more debated topics within applied biotechnologies in agriculture and environmental risk assessment. The objective of the present research was to study the potential Bt-toxin uptake by the non-target herbivore Myzus persicae Sulzer (Hemiptera: Aphididae) feeding on transgenic oilseed rape plants (Brassica napus cv. 'Westar' lines GT 2-4) expressing the Cry1Ac endotoxin. A specific aim was to replicate our previous experiment in controlled laboratory conditions to avoid or minimize the risk of contamination leading to potential false positive results. The toxin levels in vernalized (V) and not-vernalized (not-V) transgenic oilseed rape plants was also monitored to better clarify the role of physiological processes on Bt-toxin expression. Cry1Ac expression in not-V plants (mean concentration±SE=167.8±5.7 µg kg-1 FW) showed a pattern of large variability, in comparison with V plants whose expression (mean concentration±SE=227.7±1.9 µg kg-1 FW) was significantly more stable. Cry1Ac toxin was detected in three aphid samples reared on V plants with a mean toxin concentration±SE of 4.8±0.6 µg Kg-1 FW and in three out of six samples of aphids reared on not-V plants (mean toxin concentration±SE=7.1±1.2 µg kg-1 FW). The mean Bt-toxin concentration of all the positive aphid samples was 5.9±1.0 µg kg-1 FW. Our results confirmed the findings of our previous experiment and highlighted the potential for Cry1Ac toxin uptake by aphids feeding on transgenic oilseed rape plants.

Hazard mitigation or mitigation hazard?

BACKGROUND, AIM AND SCOPE: Transgenic oilseed rape (Brassica napus L.; OSR) is estimated to be environmentally and economically problematic because volunteers and ferals occur frequently and because of its hybridisation potential with several wild and weedy species. A proposed mitigation strategy aims to reduce survival, in particular in conventional OSR crops, by coupling the transgenic target modification with a dwarfing gene to reduce competitive fitness. Our study allowed us to access potential ecological implications of this strategy. MATERIALS AND METHODS: On a large scale (>500 km(2)), we recorded phenological and population parameters of oilseed rape plants for several years in rural and urban areas of Northern Germany (Bremen and surroundings). The characterising parameter were analysed for differences between wild and cultivated plants. RESULTS: In rural areas, occurrences of feral and volunteer OSR together had an average density of 1.19 populations per square kilometre, in contrast to urban areas where we found 1.68 feral populations per square kilometre on average. Throughout the survey, the vegetation cover at the locations with feral OSR ranged from less than 10% to 100%. Our investigations gave clear empirical evidence that feral OSR was, on average, at least 41% smaller than cultivated OSR, independent of phenological state after onset of flowering. DISCUSSION: The findings can be interpreted as phenotypic adaptation of feral OSR plants. Therefore, it must be asked whether dwarfing could be interpreted as an improvement of pre-adaptation to feral environments. In most of the sites where feral plants occurred, germination and establishment were in locations with disturbed vegetation cover, allowing initial growth without competition. Unless feral establishment of genetically modified dwarfed traits are specifically studied, it would not be safe to assume that the mitigation strategy of dwarfing also reduces dispersal in feral environments. CONCLUSIONS AND RECOMMENDATIONS: With respect to OSR, we argue that the proposed mitigation approach could increase escape and persistence of transgene varieties rather than reducing them. We conclude that the development of effective hazard mitigation measures in the risk evaluation of genetically modified organisms requires thorough theoretical and empirical ecological analyses rather than assumptions about abstract fitness categories that apply only in parts of the environment where the plant can occur.