Der1 promotes movement of misfolded proteins through the endoplasmic reticulum membrane

Misfolded proteins of the secretory pathway are extracted from the endoplasmic reticulum (ER), polyubiquitylated by a protein complex termed the Hmg-CoA reductase degradation ligase (HRD ligase) and degraded by cytosolic 26S proteasomes. The movement of these proteins through the lipid bilayer is assumed to occur via a protein-conducting channel of unknown nature. We show that the integral membrane protein Der1 oligomerizes, which relies on its interaction with the scaffolding protein Usa1. Mutations in the transmembrane domains of Der1 block the passage of soluble proteins across the ER membrane. As determined by site-specific photocrosslinking, the ER-luminal exposed parts of Der1 are in spatial proximity to the substrate receptor Hrd3, whereas the membrane-embedded domains reside adjacent to the ubiquitin ligase Hrd1. Intriguingly, both regions also form crosslinks to client proteins. Our data imply that Der1 initiates the export of aberrant polypeptides from the ER lumen by threading such molecules into the ER membrane and routing them to Hrd1 for ubiquitylation

Large scale processing of seismic data in search of regional and global stress patterns

A composite compute program has been devised for a fast reduction of multistation seismic data in the period range 50–500 sec for mantle surface waves and 20–100 sec for body waves. The analysis aims at the reconstruction of the seismic source from the spectrum of its far radiation field and the correlation of its parameters with its depth, size and regional environment. The capability of the computational procedure has been demonstrated in two studies of WWNSS records: one includes a spectral analysis of surface waves from a shallow shock in the Kurile Islands; the other includes a spectral analysis of P waves from 9 shocks in the depth range 550–700 km at Fiji, Mariana, Java, Japan, Peru and Brazil. Other applications of the proposed data processing routine are foreseen; a tsunami warning system and focal depth determination from spectral modal ratios. It is believed that a persistent search for stress patterns, based on the processing of a sufficiently large sample of seismic events, is essential to any future program of earthquake prediction

Ertrag und Wurzelkolonisation mit arbuskulären Mykorrhiza- Pilzen von organisch oder mineralisch gedüngtem Weizen auf trockenem, sandigen Boden

We investigated wheat yield and arbuscular mycorrhiza (AM) fungal root colonization and spore formation in response to fertilization, either with high or low amounts of mineral fertilizer or cattle manure since 27 years. At low rates there was no difference in yield between minerally and organically fertilized plants. High rates of mineral fertilizers reduced yields. Reasons can be that either the high nitrogen availability was less effectively used for grain development of minerally fertilized plants, or the mineral fertilization rendered the plants more sensitive towards drought stress. The extent of AM fungal root colonization appeared to depend on the plant P nutritional status rather than the type of fertilizer applied. The lower fertilization showed higher rates of AM root colonization. The number of AM spores, however, was higher in organically compared with minerally fertilized soil, indicating that organic fertilization increased reproduction of these beneficial microbes under dry soil conditions

Yield and arbuscular myccorhiza fungal root colonization of organically or minerally fertilized wheat grown on a dry, sandy soil

We investigated wheat yield and arbuscular mycorrhiza (AM) fungal root colonization and spore formation in response to long-term mineral or organic soil fertilization. Plots were either fertilized with high or low amounts of mineral fertilizer or cattle manure since 27 years. At low fertilization levels there was no difference in yield between minerally and organically fertilized plants. High levels of mineral fertilizer application reduced wheat yields. Probable reasons can be that either the high nitrogen availability was less effectively used for grain development of minerally fertilized plants, or the mineral fertilization rendered the plants more sensitive towards drought stress. The extent of AM fungal root colonization appeared to depend on the plant P nutritional status rather than the type of fertilizer applied. The low fertilization treatments showed higher rates of AM root colonization. The number of AM spores, however, was higher in organically compared with minerally fertilized soil, indicating that organic fertilization increased reproduction of these beneficial microbes under dry soil conditions

The interplay of Hrd3 and the molecular chaperone system ensures efficient degradation of malfolded secretory proteins

Misfolded proteins of the secretory pathway are extracted from the endoplasmic reticulum (ER), polyubiquitylated by a protein complex termed the Hmg-CoA reductase degradation ligase (HRD-ligase) and degraded by cytosolic 26S proteasomes. This process is termed ER-associated protein degradation (ERAD). We previously showed that the membrane protein Der1, which is a subunit of the HRD-ligase, is involved in the export of aberrant polypeptides from the ER. Unexpectedly, we also uncovered a close spatial proximity of Der1 and the substrate receptor Hrd3 in the ER lumen. We report here on a mutant Hrd3KR, which is selectively defective for ERAD of soluble proteins. Hrd3KR displays subtle structural changes that affect its positioning toward Der1. Furthermore, increased quantities of the ER-resident Hsp70 type chaperone Kar2 and the Hsp40 type cochaperone Scj1 bind to Hrd3KR. Noteworthy, deletion of SCJ1 impairs ERAD of model substrates and causes the accumulation of client proteins at Hrd3. Our data imply a function of Scj1 in the removal of malfolded proteins from the receptor Hrd3, which facilitates their delivery to downstream acting components like Der1

A numerical model for meltwater channel evolution in glaciers

Meltwater channels form an integral part of the hydrological system of a glacier. Better understanding of how meltwater channels develop and evolve is required to fully comprehend supraglacial and englacial meltwater drainage. Incision of supraglacial stream channels and subsequent roof closure by ice deformation has been proposed in recent literature as a possible englacial conduit formation process. Field evidence for supraglacial stream incision has been found in Svalbard and Nepal. In Iceland, where volcanic activity provides meltwater with temperatures above 0 °C, rapid enlargement of supraglacial channels has been observed. Supraglacial channels provide meltwater through englacial passages to the subglacial hydrological systems of big ice sheets, which in turn affects ice sheet motion and their contribution to eustatic sea level change. By coupling, for the first time, a numerical ice dynamic model to a hydraulic model which includes heat transfer, we investigate the evolution of meltwater channels and their incision behaviour. We present results for different, constant meltwater fluxes, different channel slopes, different meltwater temperatures, different melt rate distributions in the channel as well as temporal variations in meltwater flux. The key parameters governing incision rate and depth are channel slope, meltwater temperature loss to the ice and meltwater flux. Channel width and geometry are controlled by melt rate distribution along the channel wall. Calculated Nusselt numbers suggest that turbulent mixing is the main heat transfer mechanism in the meltwater channels studied

Der Vorteil von Stallmist gegenüber pflanzlichem organischem Dünger für den Ertrag von Rotklee und den Humusgehalt des Bodens

Die Wirkung pflanzlicher organischer Dünger (meist Leguminosenschrot) wurde bislang vorwiegend im Jahr der Anwendung, aber nicht als Langzeiteffekt auf Erträge und Bodenentwicklung untersucht. Ein direkter Vergleich mit Stallmist unter Feldbedingungen findet in der Regel nicht statt. Deshalb haben wir in einem Langzeitversuch (seit 1996) Stallmistdüngung, organische Dünger pflanzlicher Herkunft (meist Ackerbohnenschrot) und Mineraldüngung miteinander verglichen. In allen drei Schnitten brachte die Nachwirkung der pflanzlichen Dünger niedrigere Frisch- und Trockenmasse-Erträge als die N-gleichen Stallmistvarianten. Der Ertrag nach Mineraldüngung lag zwischen den beiden anderen Düngerarten, kam aber der Mistvariante meist näher als der Ackerbohnenvariante. Den insgesamt höchsten Ertrag lieferte Rotklee nach Stallmist in höherer Aufwandmenge. Die gleiche Differenzierung zeigten zuvor schon die Humusgehalte. Auch hier lag die pflanzliche organische Düngung mit 0,74 % Corg statistisch auf dem Niveau der Mineraldüngung

Characterization of Residual Chlorinated Organic Compounds in the Soil and Sediment at the Wilson`s Corner Site

Depth discrete bulk sediment samples were collected from 15 different location at the Wilson`s Corner site on the Kennedy Space Center during August 1996

Delivery of stable ultra-thin liquid sheets in vacuum for biochemical spectroscopy

The development of ultra-thin flat liquid sheets capable of running in vacuum has provided an exciting new target for X-ray absorption spectroscopy in the liquid and solution phases. Several methods have become available for delivering in-vacuum sheet jets using different nozzle designs. We compare the sheets produced by two different types of nozzle; a commercially available borosillicate glass chip using microfluidic channels to deliver colliding jets, and an in-house fabricated fan spray nozzle which compresses the liquid on an axis out of a slit to achieve collision conditions. We find in our tests that both nozzles are suitable for use in X-ray absorption spectroscopy with the fan spray nozzle producing thicker but more stable jets than the commercial nozzle. We also provide practical details of how to run these nozzles in vacuum