Is the German suspension of MON810 maize cultivation scientifically justified?

We examined the justifications invoked by the German government in April 2009 to suspend the cultivation of the genetically modified maize varieties containing the Bt insect-resistance trait MON810. We have carried out a critical examination of the alleged new data on a potential environmental impact of these varieties, namely two scientific papers describing laboratory force-feeding trials on ladybirds and daphnia, and previous data on Lepidoptera, aquatic and soil organisms. We demonstrate that the suspension is based on an incomplete list of references, ignores the widely admitted case-by-case approach, and confuses potential hazard and proven risk in the scientific procedure of risk assessment. Furthermore, we did not find any justification for this suspension in our extensive survey of the scientific literature regarding possible effects under natural field conditions on non-target animals. The vast majority of the 41 articles published in 2008 and 2009 indicate no impact on these organisms and only two articles indicate a minor effect, which is either inconsistent during the planting season or represents an indirect effect. Publications from 1996 to 2008 (376 publications) and recent meta-analyses do not allow to conclude on consistent effects either. The lower abundance of some insects concerns mainly specialized enemies of the target pest (an expected consequence of its control by Bt maize). On the contrary, Bt maize have generally a lower impact than insecticide treatment. The present review demonstrates that the available meta-knowledge on Cry1Ab expressing maize was ignored by the German government which instead used selected individual studies.     

Quantifying and Exploring Strategic Regional Priorities for Managing Natural Capital and Ecosystem Services Given Multiple Stakeholder Perspectives

A ubiquitous problem for community-based regional environmental agencies is to set strategic management priorities among a myriad of issues and multiple stakeholder perspectives. Here, we quantify the strategic management priorities for natural capital and ecosystem services using multicriteria decision analysis (MCDA) in a case study of the South Australian Murray-Darling Basin Natural Resources Management Board (the Board) region. A natural capital and ecosystem services framework was tailored to present decision-makers with a range of potential issues for strategic consideration as goal hierarchies in MCDA. Priorities were elicited from the Board and its four regionally based consultative groups using the Analytical Hierarchy Process and swing weights. Centered log ratio transformed weights were analyzed using multiple pairwise ANOVA comparisons (Dunnett’s T3) and hierarchical cluster analysis. Substantial variation in priorities occurred between decision-makers. Nonetheless, analysis of priorities for assets and services robustly demonstrated that water was the highest priority, followed by land, then biota, with atmosphere the lowest priority. Decision-makers also considered that environmental management should not impact negatively on built or social capital. Few significant differences in priorities were found between decision-maker groups. However, clusters of manager types were found which represent distinct alternative management strategies, notably the prioritization of either intermediate or final ecosystem services. The results have implications for regional environmental decision-making and suggest that embracing variation in perspectives may be a better way forward for multistakeholder MCDA. The study operationalizes natural capital and ecosystem services by providing strategic priorities for targeting management and policy within the context of community-based, regional environmental management.     

Regulatory networks for virulence and persistence of Bacillus anthracis

Bacillus anthracis, the etiological agent of anthrax, is a Gram-positive sporulating bacterium. Its life-cycle can be divided schematically into two phases: multiplication in the mammalian host and persistence in the soil. A central regulator AtxA interferes with expression of more than 70 genes in vitro and an undefined number ex vivo. The exact molecular mechanism of action of AtxA is unknown, but the involvement of cascades of relay regulators has been described. Other regulators have also been implicated in the regulatory networks; these are mainly transition state regulators, which have been studied in other Bacillus species. They contribute to the regulation of expression of virulence- and persistence-factor genes, and to the regulation of atxA itself.     

Formation of the ascidian epidermal sensory neurons: insights into the origin of the chordate peripheral nervous system

The vertebrate peripheral nervous system (PNS) originates from neural crest and placodes. While its developmental origin is the object of intense studies, little is known concerning its evolutionary history. To address this question, we analyzed the formation of the larval tail PNS in the ascidian Ciona intestinalis. The tail PNS of Ciona is made of sensory neurons located within the epidermis midlines and extending processes in the overlying tunic median fin. We show that each midline corresponds to a single longitudinal row of epidermal cells and neurons sharing common progenitors. This simple organization is observed throughout the tail epidermis, which is made of only eight single-cell rows, each expressing a specific genetic program. We next demonstrate that the epidermal neurons are specified in two consecutive steps. During cleavage and gastrula stages, the dorsal and ventral midlines are independently induced by FGF9/16/20 and the BMP ligand ADMP, respectively. Subsequently, Delta/Notch–mediated lateral inhibition controls the number of neurons formed within these neurogenic regions. These results provide a comprehensive overview of PNS formation in ascidian and uncover surprising similarities between the fate maps and embryological mechanisms underlying formation of ascidian neurogenic epidermis midlines and the vertebrate median fin.     

Human receptors patched and smoothened partially transduce hedgehog signal when expressed in Drosophila cells

In humans, dysfunctions of the Hedgehog receptors Patched and Smoothened are responsible for numerous pathologies. However, signaling mechanisms involving these receptors are less well characterized in mammals than in Drosophila. To obtain structure-function relationship information on human Patched and Smoothened, we expressed these human receptors in Drosophila Schneider 2 cells. We show here that, as its Drosophila counterpart, human Patched is able to repress the signaling pathway in the absence of Hedgehog ligand. In response to Hedgehog, human Patched is able to release Drosophila Smoothened inhibition, suggesting that human Patched is expressed in a functional state in Drosophila cells. We also provide experiments showing that human Smo, when expressed in Schneider cells, is able to bind the alkaloid cyclopamine, suggesting that it is expressed in a native conformational state. Furthermore, contrary to Drosophila Smoothened, human Smoothened does not interact with the kinesin Costal 2 and thus is unable to transduce the Hedgehog signal. Moreover, cell surface fluorescent labeling suggest that human Smoothened is enriched at the Schneider 2 plasma membrane in response to Hedgehog. These results suggest that human Smoothened is expressed in a functional state in Drosophila cells, where it undergoes a regulation of its localization comparable with its Drosophila homologue. Thus, we propose that the upstream part of the Hedgehog pathway involving Hedgehog interaction with Patched, regulation of Smoothened by Patched, and Smoothened enrichment at the plasma membrane is highly conserved between Drosophila and humans; in contrast, signaling downstream of Smoothened is different.     

An Integrative Eco-Epidemiological Analysis of West Nile Virus Transmission

West Nile disease, caused by the West Nile virus (WNV), is a mosquito-borne zoonotic disease affecting humans and horses that involves wild birds as amplifying hosts. The mechanisms of WNV transmission remain unclear in Europe where the occurrence of outbreaks has dramatically increased in recent years. We used a dataset on the competence, distribution, abundance, diversity and dispersal of wild bird hosts and mosquito vectors to test alternative hypotheses concerning the transmission of WNV in Southern France. We modelled the successive processes of introduction, amplification, dispersal and spillover of WNV to incidental hosts based on host–vector contact rates on various land cover types and over four seasons. We evaluated the relative importance of the mechanisms tested using two independent serological datasets of WNV antibodies collected in wild birds and horses. We found that the same transmission processes (seasonal virus introduction by migratory birds, Culex modestus mosquitoes as amplifying vectors, heterogeneity in avian host competence, absence of ‘dilution effect’) best explain the spatial variations in WNV seroprevalence in the two serological datasets. Our results provide new insights on the pathways of WNV introduction, amplification and spillover and the contribution of bird and mosquito species to WNV transmission in Southern France.