Landscape context modulates alien plant invasion in Mediterranean forest edges

Natural habitats in human-altered landscapes are especially vulnerable to biological invasions, especially in their edges. We aim to understand the influence of landscape and local characteristics on biological invasions by exploring the level of plant invasion and alien species traits in forest edges in highly urbanized landscapes. We identified all plant species in 73 paired plots in the edge and 50 m towards the interior of the forest. We explored the association between alien species richness and similarity in species composition between edge and interior plots with landscape and local variables, using generalized linear models and variance partitioning techniques. Then, we performed Fourth-corner analyses to explore the association between alien plant traits and local and landscape variables. In contrast to native species richness, alien species richness was more affected by the surrounding landscape than by the local characteristics of the edge. Road proximity was positively associated with alien species richness and proportion and was its most important correlate, whereas disturbance was negatively associated with native species richness and was its most influential factor. Alien plant traits were also primarily associated with landscape characteristics. For instance, species of Mediterranean origin and introduced for agriculture were associated with higher agriculture use in the landscape. Our findings suggest that risk analyses of habitat vulnerability to invasion must consider the landscape context in order to successfully predict highly invaded areas and identify potentially successful invaders.     

Assessment of Real-time PCR Based Methods for Quantification of Pollen-mediated Gene Flow from GM to Conventional Maize in a Field Study

Maize is one of the main crops worldwide and an increasing number of genetically modified (GM) maize varieties are cultivated and commercialized in many countries in parallel to conventional crops. Given the labeling rules established e.g. in the European Union and the necessary coexistence between GM and non-GM crops, it is important to determine the extent of pollen dissemination from transgenic maize to other cultivars under field conditions. The most widely used methods for quantitative detection of GMO are based on real-time PCR, which implies the results are expressed in genome percentages (in contrast to seed or grain percentages). Our objective was to assess the accuracy of real-time PCR based assays to accurately quantify the contents of transgenic grains in non-GM fields in comparison with the real cross-fertilization rate as determined by phenotypical analysis. We performed this study in a region where both GM and conventional maize are normally cultivated and used the predominant transgenic maize Mon810 in combination with a conventional maize variety which displays the characteristic of white grains (therefore allowing cross-pollination quantification as percentage of yellow grains). Our results indicated an excellent correlation between real-time PCR results and number of cross-fertilized grains at Mon810 levels of 0.1–10%. In contrast, Mon810 percentage estimated by weight of grains produced less accurate results. Finally, we present and discuss the pattern of pollen-mediated gene flow from GM to conventional maize in an example case under field conditions.     

The freshwater planarian Dugesia (G.) tigrina contains a great diversity of homeobox genes

To identify potential pattern control and cell determination and/or differentiation genes in the freshwater planarian Dugesial (G.) tigrina, we searched for homeobox genes of different types in the genome of this primitive metazoan. We applied two basic approaches: 1) Screening the cDNA library with degenerate oligonucleotides corresponding to the most conserved amino acid sequence from helix-3 of the homeodomain of each family; and 2) PCR amplification of genomic DNA or cDNA, using two sets of degenerated oligonucleotides corresponding to helices 1 and 3 of the homeodomain or two specific domains of the POU family. Using the first strategy we have identified and characterized two tissue-specific cell determination and/or differentiation NK-type homeobox genes. Using the second strategy we have identified several homeobox genes that belong to the HOM/Hox, paired (prd) or POU families.     

Lipolysis drives expression of the constitutively active receptor GPR3 to induce adipose thermogenesis

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Multiple stressors on biotic interactions: how climate change and alien species interact to affect pollination

Global change may substantially affect biodiversity and ecosystem functioning but little is known about its effects on essential biotic interactions. Since different environmental drivers rarely act in isolation it is important to consider interactive effects. Here, we focus on how two key drivers of anthropogenic environmental change, climate change and the introduction of alien species, affect plant–pollinator interactions. Based on a literature survey we identify climatically sensitive aspects of species interactions, assess potential effects of climate change on these mechanisms, and derive hypotheses that may form the basis of future research. We find that both climate change and alien species will ultimately lead to the creation of novel communities. In these communities certain interactions may no longer occur while there will also be potential for the emergence of new relationships. Alien species can both partly compensate for the often negative effects of climate change but also amplify them in some cases. Since potential positive effects are often restricted to generalist interactions among species, climate change and alien species in combination can result in significant threats to more specialist interactions involving native species.     

Spectroscopic studies on cadmium (II)- and cobalt(II)-substituted metallothionein from the crab Cancer pagurus. Evidence for one additional low-affinity metal-binding site

The binding of diamagnetic Cd(II) and paramagnetic Co(II) ions to the metal-free form of crab, Cancer pagurus, metallothionein (MT) was studied by various spectroscopic techniques. Both reconstituted and native Cd(II)-MT containing 6 mol Cd(II)/mol protein display electronic absorption, circular dichroism (CD) and magnetic circular dichroism (MCD) spectra which were indistinguishable. The stoichiometric replacement of Cd(II) ions in native Cd(II)6-MT by paramagnetic Co(II) ions enabled the geometry of the metal-binding sites to be probed. The electronic absorption and MCD spectra of Co(II)6-MT revealed features characteristic of distorted tetrahedral tetrathiolate Co(II) coordination for all six metal-binding sites. The stepwise incorporation of Cd(II) and Co(II) ions into this protein was monitored by electronic absorption and CD, and by electronic absorption and EPR spectroscopy, respectively. The results indicate that the metal-thiolate cluster structure is generated when more than four metal ions are bound. Below this titration point separate tetrahedral tetrathiolate complexes exist. This suggests that the cluster formation occurs in a two-step process. Furthermore, the spectroscopic features in both Cd(II)- and Co(II)-metal derivatives above the full metal occupancy of six suggest the existence of one additional metal-binding site. The subsequent loss of one Cd(II) ion from crab Cancer Cd(II)7-MT in the gel filtration studies demonstrate the low metal-binding affinity of the latter site. While the spectroscopic properties indicate an exclusively tetrahedral type of metal-thiolate sulfur coordination for the binding of the first six metal ions, they suggest that the seventh metal ion is coordinated in a different fashion.     

Bio-catalyzed coloration of cellulose fibers

Cotton fabrics were dyed with dyes generated in situ by laccase-catalyzed oxidative coupling of the colorless 2,5-diaminobenzenesulfonic acid (2,5-DABSA) and 1-hydroxyphenol (catechol). The enzymatic oxidation of the dye intermediates led to cross-coupling reaction products when the reaction was conducted with an excess of catechol. At least fourfold excess of catechol was necessary to achieve satisfactory dye fixation on cotton. Formation of the same colored product using either an equimolar ratio of the reagents or tenfold excess of catechol was observed. Most probably, homo-molecular reactions predominate over the cross-coupling at equimolar ratio of the precursors, while with an excess of catechol, the cross-coupling occurs in higher yield. The reaction was followed using UV-Vis spectroscopy, HPLC, FTIR and MALDI-TOF MS. A reaction pathway for laccase-induced cross-coupling of catechol and 2,5-DABSA yielding a major colored product was proposed.