Ixodes ricinus L.: mast cells, basophils and eosinophils in the sequence of cellular events in the skin of infested or re-infested rabbits

Some information on acquired resistance of rabbits against Ixodes ricinus ticks has been obtained by comparing tissue changes and cellular infiltration during 2 successive infestations, with particular emphasis on the cells involved in immediate type hypersensitivity reactions: mast cells, basophils and eosinophils. More degranulated mast cells were observed in tick lesions 2 h after the beginning of re-infestation than in the first infestation and more degranulated basophils were present on the 5th day of re-infestation. Numerous eosinophils infiltrated the dermis, especially on the 5th day of the second infestatio

Reversible intracellular translocation of KRas but not HRas in hippocampal neurons regulated by Ca2+/calmodulin

The Ras/MAPK pathway regulates synaptic plasticity and cell survival in neurons of the central nervous system. Here, we show that KRas, but not HRas, acutely translocates from the plasma membrane (PM) to the Golgi complex and early/recycling endosomes in response to neuronal activity. Translocation is reversible and mediated by the polybasic-prenyl membrane targeting motif of KRas. We provide evidence that KRas translocation occurs through sequestration of the polybasic-prenyl motif by Ca2+/calmodulin (Ca2+/CaM) and subsequent release of KRas from the PM, in a process reminiscent of GDP dissociation inhibitor–mediated membrane recycling of Rab and Rho GTPases. KRas translocation was accompanied by partial intracellular redistribution of its activity. We conclude that the polybasic-prenyl motif acts as a Ca2+/CaM-regulated molecular switch that controls PM concentration of KRas and redistributes its activity to internal sites. Our data thus define a novel signaling mechanism that differentially regulates KRas and HRas localization and activity in neurons

Book Reviews

Book Review 1Book Title: Developments in Numerical EcologyBook Authors: Edited by P. Legendre & L. LegendreSpringer-Verlag, Berlin, 1987. 585 pp., 107 figures.Book Review 2Book Title: Parasitic ProtozoaBook Authors: J.P. Kreier & J.R. BakerAllen and Unwin, Boston. 241 pages

Impact of voting advice applications on voters's decision-making

So-called online Voting Advice Applications (VAAs) have become very popular all over Europe. Millions of voters are using them as an assistance to make up their minds for which party they should vote. Despite this popularity there are only very few studies about the impact of these tools on individual electoral choice. On the basis of the Swiss VAA smartvote we present some first findings about the question whether VAAs do have a direct impact on the actual vote of their users. In deed, we find strong evidence that Swiss voters were affected by smartvote. However, our findings are somewhat contrary to the results of previous studies from other countries. Furthermore, the quality of available data for such studies needs to be improved. Future studies should pay attention to both: the improvement of the available data, as well as the explanation of the large variance of findings between the specific European countries

Are Voting Advice Applications (VVAs) more than Toys ? : First findings on Impact and Accountability of VAAs

To what extent do Voting Advice Applications (VAA) have an influence on voting behaviour and to what extent should providers be hold accountable for such tools? This paper puts forward some empirical evidence from the Swiss VAA smartvote. The enormous popularity of smartvote in the last national elections in 2007 and the feedback of users and candidates let us come to the conclusion that smartvote is more than a toy and likely to have an influence on the voting decisions. Since Swiss citizens not only vote for parties but also for candidates, and the voting recommendation of smartvote is based on the political positions of the candidates, smartvote turns out to be particularly helpful. Political scientists must not keep their hands off such tools. Scientific research is needed to understand their functioning and possibilities to manipulate elections. On the bases of a legal study we come to the conclusion, that a science driven way of setting up such tools is essential for their legitimacy. However, we do not believe that there is a single best way of setting up such a tool and rather support a market like solution with different competing tools, provided they meet minimal standards like transparency and equal access for all parties and candidates. Once the process of selecting candidates and parties are directly linked to the act of voting, all these questions will become even more salient

Die Positionierung der Nationalratskandidierenden 2007 : eine explorative Analyse der Antworten auf die Fragen der Online-Wahlhilfe smartvote

Die Studie präsentiert erste explorative Auswertungen zu den Antworten von über 2600 Kandidierenden im Rahmen der Nationalratswahlen 2007 auf den umfangreichen Fragenkatalog der Online-Wahlhilfeplattform « smartvote ». Untersucht wird, wie die Fragen von der Gesamtheit der Kandidierenden beantwortet wurden, welche Themen umstritten waren und wie sich die Kandidierenden von den Gewählten unterscheiden. Schwergewichtig beschäftigt sich die Analyse mit den Kandidierenden der vier grössten Parteien SVP, FDP, CVP und SP sowie der Grünen. Welche Positionen nehmen sie ein ? Wie geschlossen präsentieren sie sich in den einzelnen Fragen ? Wo bestehen grosse Gemeinsamkeiten, wo erheblicheUnterscheide und wie sind die Möglichkeiten der einzelnen Parteien einzuschätzen, sich politisch zu profilieren ? Schliesslich wird überprüft, wie gut die Kandidierenden zu ihrer eigenen Partei passen und welche Aussagen sich über die Zusammenhänge zwischen der Abweichung von der Parteilinie und der Herkunft von erhofften Panaschierstimmen machen lassen. Lors des élections au Conseil national en octobre 2007, plus de 2600 candidats ont répondu au questionnaire concernant l'outil de soutien au vote en ligne « smartvote ». Ce cahier de l'IDHEAP présente les résultats d'une première étude exploratoire, basée sur les réponses des candidats au questionnaire de « smartvote ». Les auteurs analysent les questions et les thèmes controversés. Ils se sont également intéressés aux différences de prises de position entre les élus et les candidats. L'accent est mis sur les candidats des grands partis, soit l'UDC, le PRD, le PDC, le PS et les Verts. Quelles sont leurs positions politiques ? Quelles sont les questions qui divisent les candidats d'un parti ? Sur quels sujets sont-ils du même avis ? Où se trouvent les points communs entre les différents partis ? Quels sont les blocs politiques qui se forment ? Sur quels thèmes les partis politiques peuvent-ils se profiler ? A l'aide d'une analyse multivariée, l'étude tente aussi d'établir si les candidats sont membres du parti politique qui représente le mieux leurs convictions. Le chapitre final discute l'influence du vote par panachage sur le positionnement politique des candidats

Pathogens, toxins, and lipid rafts

Summary: The plasma membrane is not a uniform two-dimensional space but includes various types of specialized regions containing specific lipids and proteins. These include clathrin-coated pits and caveolae. The existence of other cholesterol- and glycosphingolipid-rich microdomains has also been proposed. The aim of this review is to illustrate that these latter domains, also called lipid rafts, may be the preferential interaction sites between a variety of toxins, bacteria, and viruses and the target cell. These pathogens and toxins have hijacked components that are preferentially found in rafts, such as glycosylphosphatidylinositol-anchored proteins, sphingomyelin, and cholesterol. These molecules not only allow binding of the pathogen or toxin to the proper target cell but also appear to potentiate the toxic action. We briefly review the structure and proposed functions of cholesterol- and glycosphingolipid-rich microdomains and then describe the toxins and pathogens that interact with them. When possible the advantage conferred by the interaction with microdomains will be discusse

Editorial: Imaging synapse structure and function

These are the glory days for imaging synapse structure and function. Thanks to recent advances in both optical and electron microscopy, it is now possible to image individual synapses with unprecedented spatial and temporal resolution. The parallel development of a wide range of genetically-encoded synaptic reporters enables all-optical recording of synaptic activity in genetically-defined neuronal populations. These engineering breakthroughs allow neuroscientists to interrogate the brain in ways that were inconceivable just a few years ago. The ability to image synaptic structure and activity in large functional circuits is beginning to yield key insights into how the brain stores, processes, and computes information. This research topic consists of eleven articles (methods, primary research papers, and reviews) that provide an overview of the latest developments in synapse imaging. Rather than attempting an exhaustive list of synaptic reporters and microscopy techniques, our collection emphasizes approaches that merge technical advances from diverse areas to extract a rich palette of novel information from individual synapses. Watanabe presents a method that combines optogenetics and rapid freezing (Flash-and-Freeze) to visualize the synaptic vesicle (SV) cycle at the ultrastructural level with millisecond resolution Watanabe. This revolutionary approach revealed ultra-fast endocytosis of SVs at central synapses and neuromuscular junctions (Watanabe et al., 2013a,b) and promises to uncover many new kinetic aspects of synapse dynamics. Begemann and Galic review recent efforts to image neuronal preparations with both light and electron microscopy, with a series of hybrid techniques referred to as Correlative Light Electron Microscopy (CLEM). Jackson and Burrone describe the first genetically-encoded fluorescent reporter (sypHy-RGECO) that enables concurrent monitoring of calcium dynamics and SV fusion. sypHy-RGECO will undoubtedly be a powerful means of examining calcium triggering of SV exocytosis at the level of individual presynaptic boutons. Using similar probes, Tang et al. show that the mental disease gene DISC1 (Disrupted-In-Schizophrenia-1) accelerates SV exocytosis by facilitating calcium influx through N-type voltage-gated Ca2+ channels. Calcium transients at synapses are also shaped by both mobilization and sequestration of calcium by intracellular stores. Kwon et al. report on the latest advances in organelle-specific calcium sensors and review the contribution of the endoplasmic reticulum and mitochondria to calcium dynamics and synaptic transmission/plasticity. Until recently, one major impediment to imaging of synaptic activity has been our inability to directly measure membrane potential with adequate signal/noise ratio. This is rapidly changing with the recent improvement of a wide range of genetically-encoded voltage indicators (GEVIs) that now are capable of monitoring both single action potentials and even subthreshold synaptic potentials, both in vitro and in vivo Nakajima et al. Three papers describe recent advances on the localization, dynamics and function of postsynaptic receptors and scaffolds. Using a combination of single-molecule tracking (uPAINT) and photoactivated localization microscopy (PALM), Li and Blanpied assess the diffusion properties of membrane proteins within the postsynaptic density (PSD). The same authors recently used localization microscopy to demonstrate the existence of transsynaptic nanocolumns that align the neurotransmitter release machinery to postsynaptic receptors (Tang et al., 2016a). Dosemeci et al. review a series of EM studies that reveal the presence of a dense lamina—the “pallium”—just beneath the core layer of the PSD, and discuss how translocation of signaling proteins and scaffolds in and out of the pallium may shape activity-induced changes in dendritic spines. In keeping with the theme of postsynaptic signaling, Dore et al. discuss evidence for metabotropic functions of NMDARs, based on time-resolved FRET and other imaging approaches. Finally, at the level of synaptic circuits, two reviews describe the use of genetically-encoded synaptic labels to trace neural circuits in a variety of different model systems, ranging from C. elegans to mammals (Hong and Park; Lee et al.). Overall, we hope that the fine collection of papers contained within this research topic highlights a useful synapse imaging toolkit for the neuroscience community. The next big challenge in brain imaging will be to scale up these synaptic measurements to large ensembles of neurons to comprehend how circuits compute. This will require synaptic reporters that operate in a synaptically-relevant time scale (milliseconds), along with improved genetic targeting strategies, further advances in automated high-speed microscopy, and refined bioinformatics tools for analysis of the resulting large datasets