Synthesis of pyrrolidine C-nucleosides via Heck reaction

A novel method for the synthesis of pyrrolidine C-nucleosides has been developed. The key step of the synthesis is the palladium(0)-mediated coupling of a disubstituted N-protected 2-pyrroline and 5-iodouracil. C-Nucleoside 14 and its N-methyl derivative 15 can easily be converted to the corresponding phosphoramidite building blocks for DNA synthesis

Timing of retreat of the Reuss Glacier (Switzerland) at the end of the Last Glacial Maximum

We used cosmogenic 10Be and 36Cl to establish the timing of the onset of deglaciation after the Last Glacial Maximum of the Reuss Glacier, one of the piedmont lobes of the Alpine ice cap that reached the northern Alpine foreland in Switzerland. In this study, we sampled erratic boulders both at the frontal position in the foreland (Lenzburg and Wohlen, canton Aargau) and at the lateral Alpine border position (Seeboden moraine, Rigi, canton Schwyz). The minimum age for the beginning of retreat is 22.2 ± 1.0 ka at the frontal (terminal) position and 20.4 ± 1.0 ka at the lateral position. These ages are directly comparable with exposure ages from the other piedmont lobes in the northern Alpine foreland. Our data from the mountain called Rigi, do not support the hypothesis that boulders located external to the Seeboden moraine were deposited prior to the last glacial cycle. We present a first exposure age from an erratic boulder in a retreat position in the Alpine foreland. The Reuss Glacier was approximately 12 km behind the maximal extent no later than at 18.6 ± 0.9 ka.

Chronology of Lateglacial ice flow reorganization and deglaciation in the Gotthard Pass area, Central Swiss Alps, based on cosmogenic 10Be and in situ 14C

We reconstruct the timing of ice flow reconfiguration and deglaciation of the Central Alpine Gotthard Pass, Switzerland, using cosmogenic 10Be and in situ14C surface exposure dating. Combined with mapping of glacial erosional markers, exposure ages of bedrock surfaces reveal progressive glacier downwasting from the maximum LGM ice volume and a gradual reorganization of the paleoflow pattern with a southward migration of the ice divide. Exposure ages of ∼16–14 ka (snow corrected) give evidence for continuous early Lateglacial ice cover and indicate that the first deglaciation was contemporaneous with the decay of the large Gschnitz glacier system. In agreement with published ages from other Alpine passes, these data support the concept of large transection glaciers that persisted in the high Alps after the breakdown of the LGM ice masses in the foreland and possibly decayed as late as the onset of the Bølling warming. A younger group of ages around ∼12–13 ka records the timing of deglaciation following local glacier readvance during the Egesen stadial. Glacial erosional features and the distribution of exposure ages consistently imply that Egesen glaciers were of comparatively small volume and were following a topographically controlled paleoflow pattern. Dating of a boulder close to the pass elevation gives a minimum age of 11.1 ± 0.4 ka for final deglaciation by the end of the Younger Dryas. In situ14C data are overall in good agreement with the 10Be ages and confirm continuous exposure throughout the Holocene. However, in situ14C demonstrates that partial surface shielding, e.g. by snow, has to be incorporated in the exposure age calculations and the model of deglaciation.

Weather and War – Economic and social vulnerability in Switzerland at the end of the First World War

Neutral Switzerland – not embedded in the fighting forces – yet was involved in the Great War mainly in economical terms. Since Switzerland is a landlocked country especially agriculture became an important topic of war economy in regard to food security. Until 1916 national food supply was limited but could be maintained through barter trade. In 1916 a crisis on both supply and production level occurred and led to a decline in food availability and to immense price risings causing social turmoil. This paper aims to outline the factors of vulnerability in respect of food in Switzerland during the First World War and further it will show different coping strategies that were undertaken during that time. The paper takes the work of Mario Aeby and Christian Pfister (University of Bern) into consideration that pointed out to weather anomalies during the years 1916 and 1917 aggravating the already tense food situation. Arguing for an overlap of supply and production crisis the paper focuses on agricultural and economic history including environmental impacts. Further the paper addresses the question of what makes a food system resilient to such unforeseen impacts.

Effect of glucose on assimilatory sulphate reduction in Arabidopsis thaliana roots

With the aim of analysing the relative importance of sugar supply and nitrogen nutrition for the regulation of sulphate assimilation, the regulation of adenosine 5′‐phosphosulphate reductase (APR), a key enzyme of sulphate reduction in plants, was studied. Glucose feeding experiments with Arabidopsis thaliana cultivated with and without a nitrogen source were performed. After a 38 h dark period, APR mRNA, protein, and enzymatic activity levels decreased dramatically in roots. The addition of 0.5% (w/v) glucose to the culture medium resulted in an increase of APR levels in roots (mRNA, protein and activity), comparable to those of plants kept under normal light conditions. Treatment of roots with D‐sorbitol or D‐mannitol did not increase APR activity, indicating that osmotic stress was not involved in APR regulation. The addition of O‐acetyl‐L‐serine (OAS) also quickly and transiently increased APR levels (mRNA, protein, and activity). Feeding plants with a combination of glucose and OAS resulted in a more than additive induction of APR activity. Contrary to nitrate reductase, APR was also increased by glucose in N‐deficient plants, indicating that this effect was independent of nitrate assimilation. [35S]‐sulphate feeding experiments showed that the addition of glucose to dark‐treated roots resulted in an increased incorporation of [35S] into thiols and proteins, which corresponded to the increased levels of APR activity. Under N‐deficient conditions, glucose also increased thiol labelling, but did not increase the incorporation of label into proteins. These results demonstrate that (i) exogenously supplied glucose can replace the function of photoassimilates in roots; (ii) APR is subject to co‐ordinated metabolic control by carbon metabolism; (iii) positive sugar signalling overrides negative signalling from nitrate assimilation in APR regulation. Furthermore, signals originating from nitrogen and carbon metabolism regulate APR synergistically.

Interaction of sulfate assimilation with carbon and nitrogen metabolism in Lemna minor

Cysteine synthesis from sulfide andO-acetyl-L-serine (OAS) is a reaction interconnecting sulfate, nitrogen, and carbon assimilation. UsingLemna minor, we analyzed the effects of omission of CO2 from the atmosphere and simultaneous application of alternative carbon sources on adenosine 5′-phosphosulfate reductase (APR) and nitrate reductase (NR), the key enzymes of sulfate and nitrate assimilation, respectively. Incubation in air without CO2 led to severe decrease in APR and NR activities and mRNA levels, but ribulose-1,5-bisphosphate carboxylase/oxygenase was not considerably affected. Simultaneous addition of sucrose (Suc) prevented the reduction in enzyme activities, but not in mRNA levels. OAS, a known regulator of sulfate assimilation, could also attenuate the effect of missing CO2 on APR, but did not affect NR. When the plants were subjected to normal air after a 24-h pretreatment in air without CO2, APR and NR activities and mRNA levels recovered within the next 24 h. The addition of Suc and glucose in air without CO2 also recovered both enzyme activities, with OAS again influenced only APR.35SO4 2− feeding showed that treatment in air without CO2 severely inhibited sulfate uptake and the flux through sulfate assimilation. After a resupply of normal air or the addition of Suc, incorporation of 35S into proteins and glutathione greatly increased. OAS treatment resulted in high labeling of cysteine; the incorporation of 35S in proteins and glutathione was much less increased compared with treatment with normal air or Suc. These results corroborate the tight interconnection of sulfate, nitrate, and carbon assimilation.

Inhibition of glutathione synthesis reduces chilling tolerance in maize

The role of glutathione (GSH) in protecting plants from chilling injury was analyzed in seedlings of a chilling-tolerant maize (Zea mays L.) genotype using buthionine sulfoximine (BSO), a specific inhibitor of gamma-glutamylcysteine (gamma EC) synthetase, the first enzyme of GSH synthesis. At 25 degrees C, 1 mM BSO significantly increased cysteine and reduced GSH content and GSH reductase (GR: EC 1.6.4.2) activity, but interestingly affected neither fresh weight nor dry weight nor relative injury. Application of BSO up to 1 mM during chilling at 5 degrees C reduced the fresh and dry weights of shoots and roots and increased relative injury from 10 to almost 40%. Buthionine sulfoximine also induced a decrease in GR activity of 90 and 40% in roots and shoots, respectively. Addition of GSH or gamma EC together with BSO to the nutrient solution protected the seedlings from the BSO effect by increasing the levels of GSH and GR activity in roots and shoots. During chilling, the level of abscisic acid increased both in controls and BSO-treated seedlings and decreased after chilling in roots and shoots of the controls and in the roots of BSO-treated seedlings, but increased in their shoots. Taken together, our results show that BSO did not reduce chilling tolerance of the maize genotype analyzed by inhibiting abscisic acid accumulation but by establishing a low level of GSH. which also induced a decrease in GR activity.

Renewal of Religious Leadership According to an Ancient Model. Bishop Joseph Hubert Reinkens and Bishop Martin of Tours

Im Jahr 1866 verfasste der damals in Breslau lehrende römisch-katholische Kirchenhistoriker Joseph Hubert Reinkens eine der ersten historisch-kritischen Studien in deutscher Sprache über Martin von Tours, in der er sich u.a. mit Martins bischöflichem Leitungsdienst befasste. Nach dem Ersten Vatikanischen Konzil (1870) wurde Reinkens 1873 der erste Bischof für die Alt-Katholiken im Deutschen Reich. Der Beitrag beschreibt den Einfluss, den Reinkens' Martin-Rezeption auf sein theologisches und praktisches Verständnis des Bischofsamts hatte.