Present Status of Introductions and Spread Through Europe of Alien Pests Associated with Woody Plants (Abstract)

A recent analysis of a worldwide database of the dates of introduction of more than 17 000 animal and plant species into continents other than their native one shows that, in most groups — in particular insects and other arthropods — establishment of new species is not saturated. With globalisation has brought about an exponential increase in the rate of arrival of new alien species of terrestrial invertebrates in Europe, rising from 7 to nearly 20 per year as between the first half of the last century and today. The increase is mainly due to the arrival of plant-eating invertebrates (11.5/year) whereas the other groups are tending to regress. These plant-eating invertebrates are also significantly more associated with woody plants (8 new species per year) than with herbaceous ones. Just over 480 species, essentially insects plus some mites and nematodes, have become established on woody plants in Europe since 1800. The arrival of so-called emerging species, not known to be invasive elsewhere, is a main feature of the latest period bringing to the fore the need to define identification tools for potential invaders. The pathways and vectors of the invasion have moved to trade in ornamental plants and to a lesser degree wooden packaging, while trade in timber is more limited with just a few species having been introduced via this pathway. Furthermore, Asia has become the main source of these introductions. Another characteristic feature of the current period is the acceleration in the species’ speed of propagation once they are established. The species detected in Europe after 1990 spread approximately 3 to 4 times faster than those that had arrived earlier. The cause of this appears to be the combination of changes in economic policies implemented in Europe with the explosion of the trade in ornamental plants, particularly shrubs. nearly half of these pests confine themselves to their original alien plant, but an analysis of the variation over time in colonisation of the large groups of host woody plants shows up a recent acceleration in new species associated with eucalyptus, palm trees and other woody plants originating from regions with warm climates, suggesting that there is a connection with global warming

Catalysis of the electrochemical reduction of oxygen by bacteria isolated from electro-active biofilms formed in seawater

Biofilmsformed in aerobic seawater on stainless steel are known to be efficient catalysts of the electrochemicalreduction of oxygen. Based on their genomic analysis, seven bacterial isolates were selected and a cyclic voltammetry (CV) procedure was implemented to check their electrocatalytic activity towards oxygenreduction. All isolates exhibited close catalytic characteristics. Comparison between CVs recorded with glassy carbon and pyrolytic graphite electrodes showed that the catalytic effect was not correlated with the surface area covered by the cells. The low catalytic effect obtained with filtered isolates indicated the involvement of released redox compounds, which was confirmed by CVs performed with adsorbed iron–porphyrin. None of the isolates were able to form electro-activebiofilms under constant polarization. The capacity to catalyze oxygenreduction is shown to be a widespread property among bacteria, but the property detected by CV does not necessarily confer the ability to achieve stable oxygenreduction under constant polarization

The stone pine, Pinus pinea L., a new highly rewarding host for the invasive Leptoglossus occidentalis

Research ArticleThe invasive seed bug Leptoglossus occidentalis, a species native to Western North America, is of major concern for the producers of stone pine seeds in the Mediterranean countries. The large size of these edible seeds and their nutritive content may represent a pull factor for the seed bug. Cone and seed traits of three main Mediterranean pine species: P. pinea, P. pinaster, and P. halepensis, were evaluated. Preference trials with cone-bearing branches, individual cones and seeds were conducted to test host preference among the three host species. Considering the kernel size, stone pine seeds provide 4 to 13 times more reward than P. pinaster and P. halepensis seeds, respectively, but also needed a greater effort to be reached as measured by coat thickness. Still, the benefit/cost ratio was higher on P. pinea. Individual seeds and cones of P. pinea were 2 to 3 times more consumed than those of the two other pine species. However, branch preference trials did not reveal any difference in bug visits. Moreover, adults manifested strong group behaviour on branches, frequently dissociating into two persisting groups. The implications of these results for P. pinea producing areas are discussedinfo:eu-repo/semantics/publishedVersio

Catalysis of the electrochemical oxygen reduction reaction (ORR) by animal and human cells

Animal cells from the Vero lineage and MRC5 human cells were checked for their capacity to catalyse the electrochemical oxygen reduction reaction (ORR). The Vero cells needed 72 hours’ incubation to induce ORR catalysis. The cyclic voltammetry curves were clearly modified by the presence of the cells with a shift of ORR of 50 mV towards positive potentials and the appearance of a limiting current (59 μA.cm-2). The MRC5 cells induced considerable ORR catalysis after only 4 h of incubation with a potential shift of 110 mV but with large experimental deviation. A longer incubation time, of 24 h, made the results more reproducible with a potential shift of 90 mV. The presence of carbon nanotubes on the electrode surface or pre-treatment with foetal bovine serum or poly-D-lysine did not change the results. These data are the first demonstrations of the capability of animal and human cells to catalyse electrochemical ORR. The discussion of the possible mechanisms suggests that these pioneering observations could pave the way for electrochemical biosensors able to characterize the protective system of cells against oxidative stress and its sensitivity to external agents