Detailed Analysis of the Human Mitochondrial Contact Site Complex Indicate a Hierarchy of Subunits

Mitochondrial inner membrane folds into cristae, which significantly increase its surface and are important for mitochondrial function. The stability of cristae depends on the mitochondrial contact site (MICOS) complex. In human mitochondria, the inner membrane MICOS complex interacts with the outer membrane sorting and assembly machinery (SAM) complex, to form the mitochondrial intermembrane space bridging complex (MIB). We have created knockdown cell lines of most of the MICOS and MIB components and have used them to study the importance of the individual subunits for the cristae formation and complex stability. We show that the most important subunits of the MIB complex in human mitochondria are Mic60/Mitofilin, Mic19/CHCHD3 and an outer membrane component Sam50. We provide additional proof that ApoO indeed is a subunit of the MICOS and MIB complexes and propose the name Mic23 for this protein. According to our results, Mic25/CHCHD6, Mic27/ApoOL and Mic23/ApoO appear to be periphery subunits of the MICOS complex, because their depletion does not affect cristae morphology or stability of other components

Detection of the ADP-ribosyltransferase toxin gene (cdtA) and its activity in Clostridium difficile isolates from Equidae

Clostridium difficile is an antibiotic-associated emerging pathogen of humans and animals. Thus far three toxins of C. difficile have been described: an enterotoxin (ToxA), a cytotoxin (ToxB) and an ADP-ribosyltransferase (CDT). In the present work we describe the first isolation of CDT producing C. difficile from Equidae with gastro-intestinal disease. Out of 17 C. difficile strains isolated from Equidae, 11 were positive for the genes tcdA and tcdB encoding ToxA and ToxB. In addition four of these 11 isolates were positive for the cdtA gene encoding the catalytic subunit of the ADP-ribosyltransferase CDT. Interestingly none of the isolates derived from canines (41 isolates) and felines (4 isolates) harboured the cdtA gene. In C. difficile field isolates which contained the cdtA gene, ADP-ribosyltransferase activity could also be detected in culture supernatants indicating expression and secretion of CDT. All strains were associated with intestinal disorders, but no association was found for the occurrence of toxins with a specific clinical diagnosi

On the economic impact of international sport events: microevidence from survey data at the EURO 2008

Using firm-level data for more than 700 Swiss hotels and restaurants, we evaluate the economic impact of the EURO 2008 soccer championship in Switzerland. Although aggregated macrodata do not reveal any sizable economic impact, we report an overall negative effect based on the surveyed companies. Notably the reported effects of the individual firms are very heterogeneous. For instance, hotels in cities benefitted from the tournament as they were able to raise prices and thereby increase sales. Looking at the long-run impact only a small fraction of companies do believe in a positive effect. Interestingly, this outlook does not depend on realized sales, but on the guest structure. © 2014 © 2014 Taylor & Francis

R-Parity Violation at HERA ?

We examine the possibility that the high-Q^2 events seen at HERA are due to the production and decay of squarks of R-parity violating supersymmetry. The relevant R-parity violating coupling(s) is identified and shown to lie between 0.03 and 0.26. Consequences of such a coupling at other experiments, such as the LEP and Tevatron, are discussed

The GW space-time method for the self-energy of large systems

We present a detailed account of the GW space-time method. The method increases the size of systems whose electronic structure can be studied with a computational implementation of Hedin's GW approximation. At the heart of the method is a representation of the Green function G and the screened Coulomb interaction W in the real-space and imaginary-time domain, which allows a more efficient computation of the self-energy approximation Sigma = iGW. For intermediate steps we freely change between representations in real and reciprocal space on the one hand, and imaginary time and imaginary energy on the other, using fast Fourier transforms. The power of the method is demonstrated using the example of Si with artificially increased unit cell sizes. (C) 1999 Elsevier Science B.V

Gauged flavour symmetry for the light generations

We study the phenomenology of a model where an SU(2)^3 flavour symmetry acting on the first two generation quarks is gauged and Yukawa couplings for the light generations are generated by a see-saw mechanism involving heavy fermions needed to cancel flavour-gauge anomalies. We find that, in constrast to the SU(3)^3 case studied in the literature, most of the constraints related to the third generation, like electroweak precision bounds or B physics observables, can be evaded, while characteristic collider signatures are predicted.Comment: 16 pages, 3 figure

Nitrate-Dependent Iron Oxidation: A Potential Mars Metabolism

This work considers the hypothetical viability of microbial nitrate-dependent Fe2+ oxidation (NDFO) for supporting simple life in the context of the early Mars environment. This draws on knowledge built up over several decades of remote and in situ observation, as well as recent discoveries that have shaped current understanding of early Mars. Our current understanding is that certain early martian environments fulfill several of the key requirements for microbes with NDFO metabolism. First, abundant Fe2+ has been identified on Mars and provides evidence of an accessible electron donor; evidence of anoxia suggests that abiotic Fe2+ oxidation by molecular oxygen would not have interfered and competed with microbial iron metabolism in these environments. Second, nitrate, which can be used by some iron oxidizing microorganisms as an electron acceptor, has also been confirmed in modern aeolian and ancient sediment deposits on Mars. In addition to redox substrates, reservoirs of both organic and inorganic carbon are available for biosynthesis, and geochemical evidence suggests that lacustrine systems during the hydrologically active Noachian period (4.1–3.7 Ga) match the circumneutral pH requirements of nitrate-dependent iron-oxidizing microorganisms. As well as potentially acting as a primary producer in early martian lakes and fluvial systems, the light-independent nature of NDFO suggests that such microbes could have persisted in sub-surface aquifers long after the desiccation of the surface, provided that adequate carbon and nitrates sources were prevalent. Traces of NDFO microorganisms may be preserved in the rock record by biomineralization and cellular encrustation in zones of high Fe2+ concentrations. These processes could produce morphological biosignatures, preserve distinctive Fe-isotope variation patterns, and enhance preservation of biological organic compounds. Such biosignatures could be detectable by future missions to Mars with appropriate instrumentation

Implementation strategies for climate change adaptation measures in Dutch social housing

Housing managers are constantly confronted with the changing demands and requirements that their building stock must meet. One aspect of this is the changing climate, which is caused primarily by greenhouse gases produced by human activities. Even if the emissions of all these gases could now somehow be put on hold, the process of climate change could not be, and the effects of climate change would most probably continue to be felt for many more years. In urban areas, these effects include drought, flooding caused by extreme precipitation and heat stress caused by the urban heat island effect. In addition to threatening the building stock, climate change is also threatening the quality of life of people in urban environments. In the Netherlands, housing associations are responsible for managing the social housing stock and maintaining the quality of life of those that live there. However, research has shown that they are not yet sufficiently aware of the challenge that lies ahead in adapting their dwellings to a changing climate. In view of the focus on the physical adaptations of the building stock, it was chosen to discuss in this paper the effectiveness of three types of conceptual approaches for governance that housing associations could apply directly in their maintenance processes. The conceptual approaches are hypothesised based on the results of earlier research on the implementation of climate change adaptations in social housing. The conceptual approaches are: CA1) incorporate climate adaptation into the policy that guides the overall management of their stock; CA2) involve actors that traditionally do not play a role in the construction process, such as insurance companies and water boards; CA3) emphasise performance-based procurement to encourage the execution of projects using a partnering approach. The effectiveness of these conceptual approaches was tested using a SWOT analysis for each approach, which was discussed with practitioners. The results are five implementation strategies, based on the combinations of conceptual approaches that are potentially feasible for the implementation of climate change adaptation measures in the Dutch social housing stock. One crucial factor in these implementation strategies is collaboration, because these days no housing association is financially able to assume responsibility for climate-proofing its housing stock on its own

Assessment of the likelihood of implementation strategies for climate change adaptation measures in Dutch social housing

Housing providers have to keep adapting their building stock to keep pace with the dynamic changes in the urban environment. One of the main drivers of adaptation is climate change, caused primarily by man-made greenhouse gases. Climate change is impacting on urban areas largely through drought, flooding from extreme precipitation, and heat stress. Climate change not only threatens the building stock, but also the quality of life of people living and working in urban environments. In the Netherlands, housing associations have strong interests in and responsibilities for managing the social housing stock and maintaining quality of life, but they seem scarcely aware of the challenge that lies ahead in terms of adapting their stock to the impacts of climate change. This paper focuses on physical adaptations to the housing stock and discusses the likelihood of the adoption of five implementation strategies for climate adaptation measures as assessed by decision-makers in Dutch housing associations in an online survey. The strategies combine conceptual approaches in policymaking, involvement of external players, and the execution of construction projects in a partnering approach, with the addition of one extra strategy that assigns a central position to the tenants. There was no strategy that stood out clearly as the one most likely to guide the implementation of measures. Many housing associations do, however, see opportunities in this area and might be persuaded to take action if they were provided with a wide palette of implementation strategies from which they could select the most suitable combination