Evaluation of the potential exposure of butterflies to genetically modified maize pollen in protected areas in Italy

Environmental impacts of genetically modified crops are mandatorily assessed during their premarket phase. One of the areas of concern is the possible impact on nontarget organisms. Crops expressing Cry toxins might affect Lepidoptera larvae living outside cultivated fields, through pollen deposition on wild plants, which constitute their food source. While pollen toxicity varies among different events, possible exposure of nontarget species depends on the agro‐environmental conditions. This study was conducted in two protected areas in Italy, characterized by different climatic conditions, where many Lepidoptera species thrive in proximity to maize cultivations. To estimate the possible exposure in absence of the actual stressor (e.g., Cry1‐expressing maize plants), we conducted a two‐year field survey of butterflies and weeds. Indicator species were selected—Aglais (Inachis) io in the Northern site and Vanessa cardui in the Southern site—and their phenology was investigated. Pollen dispersal from maize fields was measured by collection in Petri dishes. Duration and frequency of exposure was defined by the overlap between pollen emission and presence of larvae on host plants. Different risk scenarios are expected in the two regions: highest exposure is foreseen for A. io in the Northern site, while minimal exposure is estimated for V. cardui in the Southern site. In the latter case, locally grown maize cultivars flower in mid‐summer in coincidence with an aestivation period for several butterfly species due to hot and dry conditions. Moreover, host plants of V. cardui are at the end of their life cycle thus limiting food availability.     

Kinetics of 21-trisomic lymphocytes

Summary Data presented here on the quantitative ³H-thymidine incorporation into DNA, after PHA mitogenic stimulation, show that 21-trisomic lymphocytes are low-responders to PHA compared with the normal-diploid ones. Their responsiveness seems to decrease with the donor's age. Autoradiographic studies clearly demonstrate that the fraction of labeled cells at the 72nd h of incubation is significantly smaller in the 21-trisomic lmphocyte population. The comparison of labeling indexes at different times of incubation (24, 48, 72 h) also indicate, in the same population, a slower increment of the portion of DNA-synthesizing cells. Discussing these data in the light of other's observations and recent progress in the knowledge of factors and mechanisms involved in the lymphocyte response to lectin mitogenic stimulus, it is suggested that differential distribution of T- and B- and/or T-cell sub-populations and a retarded cell induction time to proliferate may be two important factors negatively influencing the responsiveness of 21-trisomic lymphocyte population.     

Involvement of protein kinase C in the response of Neurospora crassa to blue light

As a first step towards understanding the process of blue light perception, and the signal transduction mechanisms involved, in Neurospora crassa we have used a pharmacological approach to screen a wide range of second messengers and chemical compounds known to interfere with the activity of well-known signal transducing molecules in vivo. We tested the influence of these compounds on the induction of the al-3 gene, a key step in light-induced carotenoid biosynthesis. This approach has implicated protein kinase C (PKC) as a component of the light transduction machinery. The conclusion is based on the effects of specific inhibitors (calphostin C and chelerythrine chloride) and activators of PKC (1,2-dihexanoyl-sn-glycerol). During vegetative growth PKC may be responsible for desensitization to light because inhibitors of the enzyme cause an increase in the total amount of mRNA transcribed after illumination. PKC is therefore proposed here to be an important regulator of transduction of the blue light signal, and may act through modification of the protein White Collar-1, which we show to be a substrate for PKC in N. crassa. Received: 4 December 1998 / Accepted: 21 May 1999     

The interplay of light and the circadian clock. Independent dual regulation of clock-controlled gene ccg-2(eas).

Ambient light is the major agent mediating entrainment of circadian rhythms and is also a major factor influencing development and morphogenesis. We show that in Neurospora crassa the expression of clock-controlled gene 2 (ccg-2), a gene under the control of the circadian clock and allelic to the developmental gene easy wettable (eas), is regulated by light in wild-type strains. Light elicits a direct and important physiological effect on ccg-2(eas) expression as demonstrated using several mutant Neurospora strains. In white collar mutants (wc-1 and wc-2) that are "blind" to blue light, ccg-2(eas) mRNA shows no variation following illumination with saturating light. By contrast, ccg-2(eas) mRNA is photoinduced in clock-null strains such as frequency (bd;frq). The results in the clock mutants show that an intact circadian oscillator is not required for light induction of ccg-2(eas). Thus, ccg-2(eas) is subject to a dual regulation that involves separable regulation by light and circadian rhythm.     

Potential impact of Coleomegilla maculata predation on adaptation of Leptinotarsa decemlineata to Bt-transgenic potatoes

The relationship between Leptinotarsa decemlineata Say egg density and Coleomegilla maculata DeGeer predatory behavior was investigated at different spatial scales (plant-to-plant and plot-to-plot). Both adult C. maculata location and daily egg consumption rates were monitored over time in greenhouse and field tests. Despite aggregation in areas of highest prey density by C. maculata, egg consumption was inversely related to egg mass density at the smallest and the largest spatial scales tested. The experimental data on predation rates in high and low density field treatments were included in a mathematical model to simulate impact of natural enemies on the rate of L. decemlineata adaptation to Bt-toxin-expressing transgenic potato plants when Bt-expressing plants are mixed at the plot-to-plot level with normal potato plants. Results showed that C. maculata predatory behavior could decrease the rate at which L. decemlineata adapted to Bt-toxins if plot-to-plot mixed-plantings were used.     

Effect of cisplatin on mitochondrial protein, glutathione, and succinate dehydrogenase in Dalton lymphoma-bearing mice

Cisplatin treatment of tumor-bearing mice resulted a significant decrease of protein in the tissues studied (liver, kidney, and Dalton lymphoma) and also in their mitochondrial fractions. As compared to respective tissues, the protein decrease was noted to be more conspicuous in their mitochondrial fractions. Similarly, mitochondrial glutathione also decreased significantly in the tissues. However, succinate dehydrogenase activity was selectively decreased in the kidney and Dalton lymphoma cells, whereas in liver it remained almost unchanged. An increase in serum urea concentration and kidney mitochondrial lipid peroxidation was also observed after cisplatin treatment. It is suggested that the cisplatin-induced biochemical changes in mitochondria involving mitochondrial protein, glutathione, and succinate dehydrogenase could be the important potent cellular sites contributing to toxicity/cytotoxicity after cisplatin treatment. This revised version was published online in July 2006 with corrections to the Cover Date.