Differences in Volatile Profiles of Turnip Plants Subjected to Single and Dual Herbivory Above- and Belowground

Plants attacked by herbivorous insects emit volatile organic compounds that are used by natural enemies to locate their host or prey. The composition of the blend is often complex and specific. It may vary qualitatively and quantitatively according to plant and herbivore species, thus providing specific information for carnivorous arthropods. Most studies have focused on simple interactions that involve one species per trophic level, and typically have investigated the aboveground parts of plants. These investigations need to be extended to more complex networks that involve multiple herbivory above- and belowground. A previous study examined whether the presence of the leaf herbivore Pieris brassicae on turnip plants (Brassica rapa subsp. rapa) influences the response of Trybliographa rapae, a specialist parasitoid of the root feeder Delia radicum. It showed that the parasitoid was not attracted by volatiles emitted by plants under simultaneous attack. Here, we analyzed differences in the herbivore induced plant volatile (HIPV) mixtures that emanate from such infested plants by using Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA). This multivariate model focuses on the differences between odor blends, and highlights the relative importance of each compound in an HIPV blend. Dual infestation resulted in several HIPVs that were present in both isolated infestation types. However, HIPVs collected from simultaneously infested plants were not the simple combination of volatiles from isolated forms of above- and belowground herbivory. Only a few specific compounds characterized the odor blend of each type of damaged plant. Indeed, some compounds were specifically induced by root herbivory (4-methyltridecane and salicylaldehyde) or shoot herbivory (methylsalicylate), whereas hexylacetate, a green leaf volatile, was specifically induced after dual herbivory. It remains to be determined whether or not these minor quantitative variations, within the background of more commonly induced odors, are involved in the reduced attraction of the root feeder’s parasitoid. The mechanisms involved in the specific modification of the odor blends emitted by dual infested turnip plants are discussed in the light of interferences between biosynthetic pathways linked to plant responses to shoot or root herbivory.     

Self-talk and emotional intelligence in university students.

The purpose of this study was to examine self-talk, year of university study, and gender as predictors of emotional intelligence in a diverse sample of 126 undergraduate participants (42 male, 84 female). Self-talk has been discussed in the literature as a means of enhancing self-awareness and self-regulation, both of which are considered important in the construct of emotional intelligence. Participants completed self-report questionnaires on self-talk and emotional intelligence. The results indicated that year of study and self-talk were significant predictors of emotional intelligence and were associated with emotional intelligence in a positive direction. Contrary to expectation, gender was not a significant predictor. The implications of the findings are discussed in terms of potential future research directions for the study of self-talk and emotional intelligence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Co-occurrence of aflatoxin B1, fumonisin B1, ochratoxin A and zearalenone in cereals and peanuts from C?te d'Ivoire.

This survey examined 30 samples of rice (n = 10), maize (n = 10) and peanuts (n = 10) from C?te d'Ivoire for aflatoxin B1, fumonisin B1 and zearalenone using immunoassays, and ochratoxin A using a validated HPLC method with fluorescence detection. In C?te d'Ivoire, as in other countries, several mycotoxins are present in the same commodities. These mycotoxins are from different structural families: aflatoxin B1, fumonisin B1, zearalenone and ochratoxin A, normally produced by fungal species from Aspergillus, Penicillium and Fusarium genera. Some samples contained four mycotoxins (86%). Four peanuts samples did not show ochratoxin A (14%), whereas they contained aflatoxin B1 concentrations above the EU regulatory limits. Concentrations of ochratoxin A, zearalenone and fumonisin B1 were low and may not cause problems per se; however, fears remain that the tolerable daily intake may be exceeded due to eating habits and synergistic effects could be important with the combination of several mycotoxins. Investigations in this direction are underway, together with isolation and characterization of the fungal species involved.     

Optimization of the dynamic wavefront control of a pulsed kilojoule/nanosecond-petawatt laser facility

The wavefront aberrations in a large-scale, flash-lamp-pumped, high-energy, high-power glass laser system can degrade considerably the quality of the final focal spot, and limit severely the repetition rate. The various aberrations induced on the Laboratoire pour l'Utilisation des Lasers Intenses (LULI), laser facility (LULI2000) throughout the amplification are identified and analyzed in detail. Based on these analyses, an optimized procedure for dynamic wavefront control is then designed and implemented. The lower-order Zernike aberrations can be effectively reduced by combining an adaptive-optics setup, comprising a bimorph deformable mirror and a four-wave lateral shearing interferometer, with a precise alignment system. This enables the laser chain to produce a reproducible focal spot close to the diffraction limit (Strehl ratio approximately 0.7). This allows also to increase the repetition rate, initially limited by the recovery time of the laser amplifiers, by a factor of 2 (one shot per hour). The proposed procedure provides an attractive alternative for dynamic correction of the wavefront aberrations of a laser facility as complex as the LULI2000.     

Identification of a Widespread Monomolecular Odor Differentially Attractive to Several <Emphasis Type="Italic">Delia Radicum</Emphasis> Ground-dwelling Predators in the Field

Dimethyl disulfide (DMDS) was identified as a major volatile constituent of Brassica napus roots heavily infested by Delia radicum, the cabbage root fly. Attractiveness of this widespread compound was tested in the field in a naturally complex odorous environment. By using an original setup especially designed for ground dwelling beetles, different concentrations of the pure molecule as well as attractiveness of the natural blend emitted by the rotten part of infested roots were tested simultaneously. The use of general linear model (GLM) statistics permitted us to finely discriminate the responses among the different treatments. The main predators of D. radicum (i.e., two staphylinids Aleochara bilineata and Aleochara bipustulata and carabid beetles of the genus Bembidion) were significantly attracted by DMDS, but responded in different ways to the natural blend and to the different concentrations tested. The dose–response curves were similar for the two staphylinids. However, whereas A. bilineata was more attracted by the natural volatile blend than by its preferred DMDS concentration, A. bipustulata was attracted as much by the natural blend as by its preferred DMDS concentration. Carabid beetles exhibited a different response. They were not attracted by the natural blend, but responded to a wider range of DMDS concentrations that included low concentrations that did not attract the staphylinid beetles. These results are discussed according to the potential resources searched by each taxon studied and their specificity for the resources. The possible use of DMDS for enhancing biological control of D. radicum is mentioned.     

A spatial model of urban winter woodsmoke concentrations

In many urban areas, residential wood burning is a significant wintertime source of PM2.5. In this study, we used a combination of fixed and mobile monitoring along with a novel spatial buffering procedure to estimate the spatial patterns of woodsmoke. Two-week average PM2.5 and levoglucosan (a marker for wood smoke) concentrations were concurrently measured at upto seven sites in the study region. In addition, pre-selected routes spanning the major population areas in and around Vancouver, B.C. were traversed during 19 cold, clear winter evenings from November, 2004 to March, 2005 by a vehicle equipped with GPS receiver and a nephelometer. Fifteen-second-average values of light scattering coefficient (bsp) were adjusted for variations between evenings and then combined into a single, highly resolved map of nighttime winter bsp levels. A relatively simple but robust (R(2) = 0.64) land use regression model was developed using selected spatial covariates to predict these temporally adjusted bsp values. The bsp values predicted by this model were also correlated with the measured average levoglucosan concentrations at our fixed site locations (R(2) = 0.66). This model, the first application of land use regression for woodsmoke, enabled the identification and prediction of previously unrecognized high woodsmoke regions within an urban airshed.     

Lead in bottled waters: contamination from glass and comparison with pristine groundwater

Using clean lab methods and protocols developed for measuring lead (Pb) in polar snow and ice, we report the abundance of Pb in 125 brands of bottled water from 28 countries. Comparison of six samples of each of three brands of water available in both glass and polyethyelene terephthalate (PET(E)) showed that the waters bottled in glass contained approximately 57, 30, and 26 times more Pb due to leaching from the containers. Excluding the bottled waters in glass, the median Pb concentration in all bottled waters was found to be 8.5 ng/L (n=185), with a range from <1 to 761 ng/L Pb. Our study includes 25 brands of bottled water from Canada, and the median Pb concentration in these samples was 15.9 ng/L (n=25), with a range from 2.1 to 268 ng/L. For comparison with the bottled waters, pristine groundwater from six artesian flows in southern Ontario, Canada, where some of the bottled waters originate, yielded a median concentration of 5.1 ng/L Pb (n=18). The median Pb concentrations reported here for bottled waters from Canada are 32-588 times less than those presented in recently published studies. In fact, all of the waters tested were well below the maximum allowable concentration established by the EU, Health Canada, and the WHO for Pb in drinking water (10 microg/L).     

Isothermal and Dynamic Microcalorimetry for Quantifying the Crystallization of an Amorphous Drug during Interactive Powder Mixing

ABSTRACT

This study reports the crystallization of amorphous nifedipine during an interactive mixing process quantified by using isothermal and dynamic microcalorimetry. Interactive mixtures of amorphous nifedipine and uniform glass beads were prepared by mixing in a Turbula® mixer. The difference in the extent of crystallization of amorphous nifedipine during mixing was characterized by the time it took for the crystallization of a known amount of amorphous nifedipine in isothermal calorimetry and the change in the height of the crystallization peak at 65°C in dynamic calorimetry. It was found that both isothermal and dynamic microcalorimetry are useful techniques for quantifying the physical transition of amorphous nifedipine during interactive mixing. The rate and extent of crystallization of amorphous nifedipine depended on both mixing time and speed, but mixing time played a more dominant role because the transformation of amorphous to crystalline nifedipine was greater after 3180 revolutions (9.7%) than after 405 revolutions (0.9%) at 27 rpm. The same trend was observed at 109 rpm, but the percentage of crystalline nifedipine after 3180 revolutions was only 5.2%. This meant that an increase in mixing time rather than speed increased the rate of amorphous to crystalline transformation. The greatest cause for crystal transformation during interactive mixing was the presence of crystal seeds of the thermodynamically stable nifedipine Modification I because the amount of amorphous to crystalline transformation increased from 2.6% for a completely amorphous mixture to 6.6% for a 92:8 mixture of amorphous and crystalline nifedipine when mixed for 30 minutes at 106 rpm.     

Enzyme-triggered radical reactions: another approach for tin-free radical chemistry

The system laccase/mediator/dioxygen is able to trigger radical reactions with radical precursors which are not natural substrates of this enzyme. The radical generation has been accomplished by single electron transfer oxidation of a 1,3-dicarbonyl precursor. The process is exemplified with a radical cascade.     

Grain accumulation of selenium species in rice (Oryza sativa L.)

Efficient Se biofortification programs require a thorough understanding of the accumulation and distribution of Se species within the rice grain. Therefore, the translocation of Se species to the filling grain and their spatial unloading were investigated. Se species were supplied via cut flag leaves of intact plants and excised panicle stems subjected to a ± stem-girdling treatment during grain fill. Total Se concentrations in the flag leaves and grain were quantified by inductively coupled plasma mass spectrometry. Spatial accumulation was investigated using synchrotron X-ray fluorescence microtomography. Selenomethionine (SeMet) and selenomethylcysteine (SeMeSeCys) were transported to the grain more efficiently than selenite and selenate. SeMet and SeMeSeCys were translocated exclusively via the phloem, while inorganic Se was transported via both the phloem and xylem. For SeMet- and SeMeSeCys-fed grain, Se dispersed throughout the external grain layers and into the endosperm and, for SeMeSeCys, into the embryo. Selenite was retained at the point of grain entry. These results demonstrate that the organic Se species SeMet and SeMeSeCys are rapidly loaded into the phloem and transported to the grain far more efficiently than inorganic species. Organic Se species are distributed more readily, and extensively, throughout the grain than selenite.