Screening fungi isolated from historic Discovery Hut on Ross Island, Antarctica for cellulose degradation

To survive in Antarctica, early explorers of Antarctica's Heroic Age erected wooden buildings and brought in large quantities of supplies. The introduction of wood and other organic materials may have provided new nutrient sources for fungi that were indigenous to Antarctica or were brought in with the materials. From 30 samples taken from Discovery Hut, 156 filamentous fungi were isolated on selective media. Of these, 108 were screened for hydrolytic activity on carboxymethyl cellulose, of which 29 demonstrated activities. Endo-1, 4-β-glucanase activity was confirmed in the extracellular supernatant from seven isolates when grown at 4°C, and also when they were grown at 15°C. Cladosporium oxysporum and Geomyces sp. were shown to grow on a variety of synthetic cellulose substrates and to use cellulose as a nutrient source at temperate and cold temperatures. The research findings from the present study demonstrate that Antarctic filamentous fungi isolated from a variety of substrates (wood, straw, and food stuffs) are capable of cellulose degradation and can grow well at low temperatures

Additional Exploratory Photoelastic Studies in Stress Wave Propagation

In a previous report to the sponsor, the design and description of a high speed framing camera was presented along with several film strips representing the results of a series of qualitative investigations of dynamic stress wave phenomena. These studies included crack propagation, layered media, compressed bars and beams, and cross sections of rocket heads. As part of a continuing study in these and related fields, a final report is submitted covering (1) exploratory experimental studies of shock wave propagation initiated by explosive caps and by nitrogen shock wave impingement, and (2) theoretical studies of a series of dynamic stress wave problems carried out in conjunction with the overall problem

Spatially Localized Synthesis and Structural Characterization of Platinum Nanocrystals Obtained Using UV Light

Platinum nanocrystals with a fine control of the crystal domain size in the range 1.0–2.2 nm are produced by tuning the NaOH concentration during the UV-induced reduction of H$_2$PtCl$_6$ in surfactant-free alkaline ethylene glycol. The colloidal solutions obtained are characterized by transmission electron microscopy and pair distribution function analysis, allowing analysis of both atomic and nanoscale structures. The obtained nanoparticles exhibit a face-centered cubic crystal structure even for the smallest nanoparticles, and the cubic unit cell parameter is significantly reduced with decreasing crystallite size. It is further demonstrated how the “UV-approach” can be used to achieve spatial control of the nucleation and growth of the platinum nanocrystals, which is not possible by thermal reduction

Present-day surface deformation of the Alpine region inferred from geodetic techniques

We provide a present-day surface-kinematics model for the Alpine region and surroundings based on a high-level data analysis of about 300 geodetic stations continuously operating over more than 12 years. This model includes a deformation model, a continuous surface-kinematic (velocity) field, and a strain field consistently assessed for the entire Alpine mountain belt. Special care is given to the use of the newest Global Navigation Satellite Systems (GNSS) processing standards to determine high-precision 3-D station coordinates. The coordinate solution refers to the reference frame IGb08, epoch 2010.0. The mean precision of the station positions at the reference epoch is ±1.1&thinsp;mm in N and E and ±2.3&thinsp;mm in height. The mean precision of the station velocities is ±0.2&thinsp;mm&thinsp;a−1 in N and E and ±0.4&thinsp;mm&thinsp;a−1 in height. The deformation model is derived from the point-wise station velocities using a geodetic least-squares collocation (LSC) approach with empirically determined covariance functions. According to our results, no significant horizontal deformation is detected in the Western Alps, while across the Southern and Eastern Alps the deformation vectors describe a progressive eastward rotation towards Pannonia. This kinematic pattern also makes evident an increasing magnitude of the deformation from 0.1&thinsp;mm&thinsp;a−1 in the western part of Switzerland up to about 1.3&thinsp;mm&thinsp;a−1 in the Austrian Alps. The largest shortening is observed along the southern front of the Eastern Alps (in the northern area of the Venetian-Friuli Basin) and in the northern part of the Apennine Peninsula, where rates reach 2 and 3&thinsp;mm&thinsp;a−1, respectively. The average accuracy of the horizontal deformation model is ±0.2&thinsp;mm&thinsp;a−1. Regarding the vertical kinematics, our results clearly show an ongoing average uplift rate of 1.8&thinsp;mm&thinsp;a−1 of the entire mountain chain, with the exception of the southern part of the Western Alps, where no significant uplift (less than 0.5&thinsp;mm&thinsp;a−1) is detected. The fastest uplift rates (more than 2&thinsp;mm&thinsp;a−1) occur in the central area of the Western Alps, in the Swiss Alps, and in the Southern Alps in the boundary region between Switzerland, Austria, and Italy. The general uplift observed across the Alpine mountain chain decreases towards the outer regions to stable values between 0.0 and 0.5&thinsp;mm&thinsp;a−1 and, in some cases, to subsidence like in the Liguro-Provençal and Vienna basins, where vertical rates of −0.8 and −0.3&thinsp;mm&thinsp;a−1 are observed, respectively. In the surrounding region, three regional subsidence regimes are identified: the Rhône-Bresse Graben with −0.8&thinsp;mm&thinsp;a−1, the Rhine Graben with −1.3&thinsp;mm&thinsp;a−1, and the Venetian-Friuli Basin with −1.5&thinsp;mm&thinsp;a−1. The estimated uncertainty of our vertical motion model across the Alpine mountain belt is about ±0.3&thinsp;mm&thinsp;a−1. The strain field inferred from the deformation model shows two main contrasting strain regimes: (i) shortening across the south-eastern front of the Alps and the northern part of the Dinarides and (ii) extension in the Apennines. The pattern of the principal strain axes indicates that the compression directions are more or less perpendicular to the thrust belt fronts, reaching maximum values of 20×10−9&thinsp;a−1 in the Venetian-Friuli and Po basins. Across the Alpine mountain belt, we observe a slight dilatation regime in the Western Alps, which smoothly changes to a contraction regime in western Austria and southern Germany, reaching maximum shortening values of 6×10−9&thinsp;a−1 in north-eastern Austria. The numerical results of this study are available at https://doi.pangaea.de/10.1594/PANGAEA.886889.</p

Structural and mechanistic basis for translation inhibition by macrolide and ketolide antibiotics

Macrolides and ketolides comprise a family of clinically important antibiotics that inhibit protein synthesis by binding within the exit tunnel of the bacterial ribosome. While these antibiotics are known to interrupt translation at specific sequence motifs, with ketolides predominantly stalling at Arg/Lys-X-Arg/Lys motifs and macrolides displaying a broader specificity, a structural basis for their context-specific action has been lacking. Here, we present structures of ribosomes arrested during the synthesis of an Arg-Leu-Arg sequence by the macrolide erythromycin (ERY) and the ketolide telithromycin (TEL). Together with deep mutagenesis and molecular dynamics simulations, the structures reveal how ERY and TEL interplay with the Arg-Leu-Arg motif to induce translational arrest and illuminate the basis for the less stringent sequence-specific action of ERY over TEL. Because programmed stalling at the Arg/Lys-X-Arg/Lys motifs is used to activate expression of antibiotic resistance genes, our study also provides important insights for future development of improved macrolide antibiotics

Frozen and Invariant Quantum Discord under Local Dephasing Noise

In this chapter, we intend to explore and review some remarkable dynamical properties of quantum discord under various different open quantum system models. Specifically, our discussion will include several concepts connected to the phenomena of time invariant and frozen quantum discord. Furthermore, we will elaborate on the relation of these two phenomena to the non-Markovian features of the open system dynamics and to the usage of dynamical decoupling protocols.Comment: 29 pages, 8 figure