A “dock, lock, and latch” Structural Model for a Staphylococcal Adhesin Binding to Fibrinogen

AbstractGram-positive pathogens such as staphylococci contain multiple cell wall-anchored proteins that serve as an interface between the microbe and its environment. Some of these proteins act as adhesins and mediate bacterial attachment to host tissues. SdrG is a cell wall-anchored adhesin from Staphylococcus epidermidis that binds to the Bβ chain of human fibrinogen (Fg) and is necessary and sufficient for bacterial attachment to Fg-coated biomaterials. Here, we present the crystal structures of the ligand binding region of SdrG as an apoprotein and in complex with a synthetic peptide analogous to its binding site in Fg. Analysis of the crystal structures, along with mutational studies of both the protein and of the peptide, reveals that SdrG binds to its ligand with a dynamic “dock, lock, and latch” mechanism. We propose that this mechanism represents a general mode of ligand binding for structurally related cell wall-anchored proteins of gram-positive bacteria

A decreasing glacier mass balance gradient from the edge of the Upper Tarim Basin to the Karakoram during 2000-2014

In contrast to the glacier mass losses observed at other locations around the world, some glaciers in the High Mountains of Asia appear to have gained mass in recent decades. However, changes in digital elevation models indicate that glaciers in Karakoram and Pamir have gained mass, while recent laser altimetry data indicate mass gain centred on West Kunlun. Here, we obtain results that are essentially consistent with those from altimetry, but with two-dimensional observations and higher resolution. We produced elevation models using radar interferometry applied to bistatic data gathered between 2011 and 2014 and compared them to a model produced from bistatic data collected in 2000. The glaciers in West Kunlun, Eastern Pamir and the northern part of Karakoram experienced a clear mass gain of 0.043 ± 0.078~0.363 ± 0.065 m w.e. yr−1. The Karakoram showed a near-stable mass balance in its western part (−0.020 ± 0.064 m w.e. yr−1), while the Eastern Karakoram showed mass loss (−0.101 ± 0.058 m w.e. yr−1). Significant positive glacier mass balances are noted along the edge of the Upper Tarim Basin and indicate a decreasing gradient from northeast to southwest

Northern Eurasia Future Initiative (NEFI): facing the challenges and pathways of global change in the 21st century

During the past several decades, the Earth system has changed significantly, especially across Northern Eurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted in a variety of regional environmental changes that can have global consequences. The Northern Eurasia Future Initiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth Science Partnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoing environmental change, to inform societies and, thus, to better prepare societies for future developments. A key principle of NEFI is that these developments must now be secured through science-based strategies co-designed with regional decision makers to lead their societies to prosperity in the face of environmental and institutional challenges. NEESPI scientific research, data, and models have created a solid knowledge base to support the NEFI program. This paper presents the NEFI research vision consensus based on that knowledge. It provides the reader with samples of recent accomplishments in regional studies and formulates new NEFI science questions. To address these questions, nine research foci are identified and their selections are briefly justified. These foci include: warming of the Arctic; changing frequency, pattern, and intensity of extreme and inclement environmental conditions; retreat of the cryosphere; changes in terrestrial water cycles; changes in the biosphere; pressures on land-use; changes in infrastructure; societal actions in response to environmental change; and quantification of Northern Eurasia's role in the global Earth system. Powerful feedbacks between the Earth and human systems in Northern Eurasia (e.g., mega-fires, droughts, depletion of the cryosphere essential for water supply, retreat of sea ice) result from past and current human activities (e.g., large scale water withdrawals, land use and governance change) and potentially restrict or provide new opportunities for future human activities. Therefore, we propose that Integrated Assessment Models are needed as the final stage of global change assessment. The overarching goal of this NEFI modeling effort will enable evaluation of economic decisions in response to changing environmental conditions and justification of mitigation and adaptation efforts

Study of surface phenomena in flotation: new methods and reagents Final report

Available from TIB Hannover: DtF QN1(47,48) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Optische Rotationssensoren 2: Kompakte optische Gyroskope mit faser- und integriert-optischen Systemkomponenten Schlussbericht

The research is directed to improvement of parameters (sensitivity, bias and scale factor stability), development of wideband light sources, more robust and simpler types for civilian applications. Goals of the project: Breadboarding gyros of low volumes using fiber optic depolarizers, common fibers, highly birefringent fibers, and integrated optic chips, application of novel modulation and calibration methods. Therefore fiber optic devices of excellent performance parameters (polarizers, depolarizers, phase modulators) and integrated optic chips (LiNbO_3:PE) have been developed and four different gyroscope types were investigated. The parameters correspond to the calculated ones (e.g. bias stability with polarization maintaining fibers <0,2 deg/h (all-fiber) and <2 deg/h (IO-chip), sensitivity (#DELTA#f=0,12 Hz)#<=#0,18 deg/h and 1,2 deg/h, respectively. The results are usable for further improvement of medium performance types. The fiber and integrated optic devices are applicable for sensing and communication technique, the modulation and calibration methods for optical measurement technique, too. (orig.)Die Forschung ist auf weitere Parameterverbesserung (Empfindlichkeit, Nullpunkt- und Skalenfaktorstabilitaet), Entwicklung breitbandiger Lichtquellen, robustere und einfachere Typen fuer zivile Anwendungen konzentriert. Ziele des Projektes: Realisierung von Labormustern mit geringem Volumen unter Nutzung faseroptischer Depolarisatoren, normaler LLF, hochdoppelbrechender Fasern und integriert-optischer Chips, Anwendung neuer Modulations- und Kalibrationstechniken. Dazu wurden faseroptische Bauelemente mit sehr guten Eigenschaften (Polarisatoren, Depolarisatoren, Phasenmodulatoren) und integriert-optische Chips (LiNbO_3:PE) entwickelt und 4 verschiedene Gyroskoptypen untersucht. Die Parameter entsprechen den berechneten (z.B. Nullpunktstabilitaet mit polarisationserhaltenden Fasern <0,2 grd/h (Allfaser) bzw. <2 grd/h (IO-Chip), Empfindlichkeit (#DELTA#f=0,12 Hz)#<=#0,18 grd/h bzw. 1,2 grd/h). Die Ergebnisse koennen zur Weiterentwicklung von medium performance-Typen genutzt werden. Die faser- und integriert optischen Bauelemente sind auch fuer Sensorik und Kommunikationstechnik, die Modulations-und Kalibrationsverfahren fuer die optische Messtechnik einsetzbar. (orig.)SIGLEAvailable from TIB Hannover: F93B114+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman